To do its job without sinking or shifting, a footing must rest on stable, undisturbed
soil. A footing beneath a foundation wall also must have adequate drainage to
avoid damage from hydraulic. To make sure you've planned for the demands of
your particular climate and soil conditions, consult with your local building
department.
o Install batter boards. Lay out the job, driving in stakes to mark the wall's
outside corners. Place batter boards about 3 feet beyond these stakes by
driving in 1x4 or 2x4 stakes and attaching 3- to 5-foot-long horizontal pieces
to them. Fasten with drywall screws. (Nailing will loosen the stakes.)
o Lay out the site. Attach mason's lines to the batter boards and the house.
Transfer the line marking the outside of the wall to the batter boards by
having someone dangle a plumb bob over the outer edge of each perimeter
stake while you stretch the mason's line. When the lines intersect over the
stake, mark the points where the mason’s lines cross the batter boards.
Now that you have marked for the outside of the wall (B), measure over on
the batter board and mark for the inside edge of the footing (A), the outside
edge of the footing (C), and the outer excavation line (D). The dimensions
shown in the inset above are for an 8-inch-wide wall and, thus, a 16-inch-
wide footing.
o Dig trench and lay out footing. It may not be necessary to build forms for
your footings. Depending on your local codes and the nature of your project,
simply digging a trench for the footing may suffice. Check with your local
building department.
Digging a hole as big and as deep as needed for a wall footing can be a
slow, back-breaking job, so consider hiring an excavator or renting a small
backhoe or trench digger. Dig the trench to the top of the footing or to about
3 inches below the top of the footing if you will be building a form.
Use a plumb bob to locate the outside corners of the footing. Partially drive
in the stakes that line up with the outside edges of your forming lumber.
Follow the same procedure to position the form stakes for the inside edge of
the footing form.
o Level tops of stakes. If there is a footing on the existing structure, drive in
form stakes so the tops of the stakes are at the same level as that footing.
Or, drive a stake so its top is at the correct depth of the footing top. Then
drive the outside corner stakes so they are level with those next to the
building. Check for level with a line level or carpenter's level resting on a
straight board.
• Working with Mortar. Laying bricks in mortar is a skill that requires practice
before you become proficient. You probably will never be able to throw mortar and
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lay bricks as quickly as a journeyman, but with patience you can learn to make
straight walls with clean joints.
Professional masons take their mortar seriously. Mortar must be just the right
consistency, neither soupy nor dry. It must have the correct ratio of sand, lime, and
cement. Otherwise, laying bricks will be a struggle and it will be difficult to keep the
courses even. For small jobs and repair work, use premixed mortar that contains
sand. For larger jobs, you may be able to save money by buying the sand and the
cement separately and mixing them yourself.
o Mix the mortar. Consult your supplier for the best mix for your area and
your project. In most cases, a good ratio is 4 parts sand, 1/2 part lime, and 1
part mason's cement. Adding lime and sand weakens the mortar. Measure
by shovelfuls. Mix small batches in a wheelbarrow; for larger jobs use a
mortar box. Shovel in half the sand, then all the mortar and lime, then the
rest of the sand. Mix the dry materials thoroughly, then carefully mix in clean
water a little bit at a time.
o Test the mortar. Pick up a small amount of mortar with your trowel and
quickly turn the trowel upside down. If the mortar sticks to the trowel, it is
the correct consistency. If the mortar stiffens before you use it all, add water
and remix. But if it stiffens a second time, throw it out and make a new
batch.
o Pick up the mortar. Drop a shovelful of mortar onto the mortarboard. Place
the mortarboard close to your work and keep it at a comfortable height so it
will be easy to move mortar onto the wall. Simply getting the mortar on your
brick trowel in the correct position takes some practice. Slice off a gob and
shape it so it is about the size and shape of your trowel. Scoop it up with a
smooth sweep, giving a slight upward jerk with your wrist to make the
mortar stick firmly to the trowel. Take the time to practice this essential
technique.
o Throw the mortar. Bricklayers talk of "throwing" mortar for a reason. Don't
try to carefully place it. In one motion, flick your wrist and pull the trowel
toward you. Plopping the mortar onto the bricks helps it adhere better.
Using a standard-size brick trowel with the correct amount of mortar, you
can throw enough mortar for two bricks.
o Furrow the mortar. Spread the mortar to an even thickness if necessary.
Lightly draw the point of the trowel across the length of the mortar to make a
furrow down its middle. Don't make the furrow too deep or you may form an
air pocket.
o Butter the brick end. Some bricks stick better if they are dampened. Ask
your supplier if this is recommended. After the corner brick is laid, butter
one end of the other bricks using a scraping motion with the trowel.
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o Place the brick, remove excess. Place each brick so you have to slide it
only slightly into place. Push it firmly up against the preceding brick.
Immediately slice off the excess mortar oozing from the sides; use this
excess as part of your next trowel load.
• Curing Concrete. Proper curing can make or break a concrete project. Hydration,
the chemical process that hardens cement, stops after the concrete first sets,
unless you keep it moist and fairly warm. Without adequate hydration, the concrete
will be weak.
Whether you choose to cover or periodically spray the concrete, keep it damp or
wet for several days after pouring it. If the weather is cold, insulate the concrete
during curing by spreading straw over the top of it.
o Cover with burlap or plastic. The most effective curing method is to cover
the concrete surface with burlap or old blankets and keep these wet with
frequent watering. Be sure the fabric is clean so you won't stain the
concrete. Place the covering on the concrete as soon as it is hard enough to
resist surface damage. Weight down the covering with scraps of lumber. If
you cannot wet the surface periodically, cover it with plastic sheeting. This
traps moisture and works as well as wet cloth.
o Keep a sprinkler running. Frequent wetting with a lawn sprinkler, especially
during daylight hours in the summer, also provides the moisture concrete
needs to cure slowly. Before spraying the water, make sure the concrete is
set hard enough so the spray will not damage the surface. If you apply too
much water before the concrete is set, it could cause spalling or chipping at
a later date, which can ruin the job.
o Cover with straw. If cold weather strikes after the pour, spread 6 to 12
inches of dry straw or hay over the concrete, then cover the straw with
canvas or plastic sheeting. Be especially careful to cover the edges and
corners of slabs.
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JOB SHEET # 3-1
Title Hands-on activities on constructing a marine finfish
Purpose hatchery
To enable the participants to gain hands-on learning on
constructing a marine finfish hatchery
Equipment, Tools and Materials Mixer, cement, nails, site and construction plan,
Precautions Observe personal safety practices in hatchery
construction
Procedures:
Hands On Exercise #1. Drawing up a construction timetable
Construction Timetable. A review has to be undertaken to determine the logical
construction sequence. The optimum time for each construction phase is estimated by
carefully analyzing all the activities needed to be performed. Since construction time is
also highly influenced by the number of workers assigned to the task, an iterative
procedure with manpower planning is essential. The end product of this exercise is a
time-series chart where the different phases of construction are laid out in time-based
logical and sequential order. Time “floats” are normally built into the estimates to reckon
with possible delays due to uncertainties. The construction timetable will provide:
The earliest and latest project completion dates;
The earliest and latest start and finish of each construction phase;
and,
The logical sequence or inter-dependence of the various construction
phases.
Hands On Exercise #2. Measuring and Leveling.
There's a good reason why the first rule of carpentry is, "Measure twice, cut once." Small
mistakes add up, producing sloppy results. If you don't catch the error, you may throw the
whole deck out of whack and have to dismantle it and rebuild.
All carpentry projects require that you understand how to establish level references. The
art of finding level isn't just for the purpose of creating flat surfaces; it is also necessary
for ensuring accurate measurements. A tape measure works only along two dimensions.
If you are not measuring along a level surface, the measurement is compromised. For
example, if you lay out your deck by measuring from the house along a sloping yard,
rather than along a level plane, you could wind up with dimensions several inches, or
even several feet, wrong.
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o Using a tape measure. The hook at the end of a tape measure slides back
and forth slightly to compensate for its own thickness. This means that
whether you hook the tape on a board end for an outside measurement or
push it against a flat surface for an inside measurement, the reading is still
accurate. The first few inches of many tape measures are divided into 1/32-
inch increments for detailed measurements.
o Extending the level with a board. To establish level between posts, place a
carpenter's level on the edge of a straight board. Sight down the board to
make sure it is straight. If necessary, use tape to keep the level centered on
the board. With a carpenter's level, you know you have a level surface when
the bubble in the horizontal vial centers between the two lines.
o Using a water level for large spans. Used properly, a water level is an
unerringly accurate tool for finding level. Although not necessary on smaller
decks, it may be indispensable for large decks or for checking level around
corners. You can make a water level with plastic tubing filled with water, or
you can buy a commercial model like the one shown.
o Estimating with a line level. Inexpensive line levels are handy for making
rough estimates, but they are not as accurate as a carpenter's level or a
water level. Clip the level on a mason's line, then adjust the line until the
level's bubble is centered. The line must be as taut as possible, and there
should be little if any wind affecting the mason's line.
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SELF CHECK #3-1
1. Enumerate the principal pre-construction activities.
2. What is the role of management in the construction proper?
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ANSWER KEY #3-1
1. Enumerate the principal pre-construction activities.
Answer:
• Pre-Construction Activities. The initial move to get the construction under way
is for the Project Manager to convene a pre-construction forum to gather and
analyze all relevant documents (e.g. Construction Plans, Site Plan, etc.) and
information (e.g. owner’s preferences, resources availability, etc.) for the purpose
of determining:
o Construction Timetable. The construction timetable will provide:
The earliest and latest project completion dates;
The earliest and latest start and finish of each construction phase;
and,
The logical sequence or inter-dependence of the various construction
phases.
o Manpower Requirement. A Manpower Plan showing the following
information is developed:
The numbers and skills of workers needed for specified durations of
time, and for specific construction phases;
A contingency factor is often reflected to indicate the additional
number of workers that will be needed if work duration is needed to
be hastened or compressed.
Manpower costs are determined based on prevailing industry and
market rates.
o Materials and Equipment Requirements and Deadlines. Based likewise on
the Construction Timetable, all the materials and equipment rentals or
acquisitions are determined.
o Financial Requirements. The financial implications of the Manpower Plan
and the Materials and Equipment Plan are summarized in a Financial Plan
which is comprised of:
The total cost of the construction project: divided by phase, type of
activity, and nature of expenditure; and,
Cash Flows that signals the amounts of financial resources at
specific time intervals needed to support the on-going construction.
o Management Team. To oversee all these plans, a construction
management team is formed. The Project Manager is identified, as well as
the Project Engineer, and all other key construction staff: Logistics Officer,
Safety Officer, Field Supervisor, Foreman, etc. Their specific roles, duties
and responsibilities are determined. The chain of command is clearly
established.
o Use of Contractors. Unless the construction is very small or limited,
construction jobs are usually contracted out to qualified contractors for two
(2) major reasons:
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They have access to a ready pool of skills and crafts which otherwise
will normally create big problems if the construction is managed in-
house; and,
They are more technically qualified and competent to assure
availability of technical know-how to ensure quality control in
construction.
2. What is the role of management in the construction proper?
Answer:
• Implementation Stage. Even with a contractor, management has to effectively
intervene in the following manner:
o Work Monitoring. Progress of the work has to be monitored regularly.
Actual accomplishments must be plotted against the Construction
Timetable. Delays must be analyzed whether:
They can be accommodated by the “slacks” or buffer time estimates;
or
They will cause delays in the completion of the whole project.
Risks of project delays must be given serious attention. How will it impact
on costs? How will it adversely affect operations and the overall financial
targets of the project?
o Site Management. While the contractor is responsible for getting the
construction jobs done, it is the responsibility of management to ensure that
safety, discipline, and order is maintained at the job site.
o Financial Management. Definitely, financial management is a principal
concern of management. The project must be accomplished within budget.
Wastages must be minimized. Cost-effectiveness must be promoted by
improving processes and procedures in construction.
o Procurement and Materials Management. Contractor services are normally
limited to the provision of services. The procurement, stocking, and
issuance of materials and equipment are usually retained by management.
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QUALIFICATION : AQUACULTURE NC III
UNIT OF COMPETENCY
MODULE TITLE : OPERATE MARINE FINFISH HATCHERY
LEARNING OUTCOME #4 : Designing, Lay-outing, and Construction of a Marine
Finfish hatchery
: Install life support
ASSESSMENT CRITERIA
1. Life support system are identified and explained
2. Installation of life support system is explained and demonstrated
3. Personal safety is observed
RESOURCES Tools and Instruments Supplies and Materials
1. Electrical materials
Equipment and Facilities 1. PVC/G.I. pipe
2. Regulating valve
1. Water pump 3. Electrical tools
2. Aerators/blowers 4. Hand tools
5. Safety shoes
6. Gloves
REFERENCES
De la Pena, M. R., Fermin, A. C., and Lojera, D. P. 1995. The use of brackishwater
cladoceran, Diaphanosoma celebenesis (Stingelin), as partial replacement for
Artemia in the hatchery rearing of sea bass, Lates Calcarifer (Bloch) fry.
Presented at the Fourth Asian Fisheries Forum: Beijing, China; 16-20 October
1995.
Dhert, P., Duray, M. Lavens, P. and Sorgeloos, P. 1990. Optimized feeding strategies in
the larviculture of the asian sea bass (Lates Calcarifer). In: Hirano, R., and Hanyo,
I. (eds) The Second Asian Fisheries Forum: Proceedings of the Second Asian
Fisheries Forum; 17-22 April 1989; Tokyo, Japan. Pp. 319-323.
Doi, M. M., bin, Hj., Nawi, N., Razali bin Nik Lah and bin Talib, Z. 1991. Artificial
propagation of the grouper Epinephelus suillus at the marine hatchery in Tanjong
Demong, Tereggana, Malaysia Dept. of Fishery, Ministry of Agriculture, Malaysia.
41pp.
Code No. Designing, Lay-outing and Constructing of a Date: Date Page #
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Duray, M. and Juario, J. V. 1988. Broodstock Management and Seed Production of the
rabbitfish, Siganus guttatus (bloch) and sea bass, Lates Calcarifer (Bloch). In:
Juario, J. V. and Benitez, L. V. (eds) Perspective in Aquaculture Development in
Southeast Asia and Japan: Proceedings of the Seminar on Aquaculture
Development in Southeast Asian, 8-12 September 1987, SEAFDEC/AQD, Iloilo
City, Philippines, pp. 195-210.
Guanzon, Nicolas G, de Castro-Mallare, Teresa R & Lorque, Felizardo M (2004)
Polyculture of milkfish Chanos chanos (Forsskal) and the red seaweed
Gracilariopsis bailinae (Zhang et Xia) in brackish water earthen ponds.
Aquaculture Research 35 (5), 423-431.
Kungvankij, P., Tiro, L. B., Pudadera, B. J., and Potestas, I. O. 1988. Biology and culture
of sea bass (Lates Calcarifer). NACA Training Manual Series No. 3, Reprinted by
SEAFDEC/AQD, Tigbauan, Iloilo, Philippines. 70pp.
National Institute of Coastal Aquaculture. 1986. Technical manual for seed production of
sea bass. March 1986. Kao Seng, Songkhla, Thailand. 49pp.
Ruangpanit, N., Bunliptanon, P., Pechmanee, T., Arkayanont, P. and Vanakovat, J. 1986.
Popagation of grouper, Epinephelus malabaricus at National Institute of Coastal
Aquaculture, Songkhla, Technical Paper No. 5/1988, National Institute of Coastal
Aquaculture, Songkhla, Thailand. 16pp.
Sakares, V. and Sukbanaung, S. 1987. Experimental on net cage culture of grouper
Epinephelus tauvina using different stocking density. In: Proceeding of meeting
on “Reconsidering or results of research on grouper propagation at National
Institute of Coastal Aquaculture, Songkhla 23-25February 1987, pp. 165-177.
Sumagaysay, N. S., Hilomen-Garcia, G. V., and Garcia, L. M. B. 1999. Growth and
production of deformed and non-deformed hatchery-bred milkfish (chanos chanos)
in brackishwater ponds. The Israeli Journal of Aquaculture – Bamidgeh 51 (3):
106-113
Sumagaysay, N.; Baliao, D.; Rodriguez, E.; Coloso, R.M.; Lückstädt, C.:
AQD recommends semi-intensive milkfish culture.
In: SEAFDEC Asian Aquaculture, Band 20, Heft 2, 1998, S. 28-29
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Learning Outcome # 4: Install life support
LEARNING ACTIVITIES SPECIAL INSTRUCTIONS
Read and learn on topics relating in
1. Read and study carefully the following installing life support system for the
sheets: marine finfish hatchery.
• Information sheet # 4-1: “The piping Please refer to Job Sheet #4-1 for more
system” details and follow the instructions.
• Information sheet # 4-2:”Determining
the type of aerator systems”
• Information sheet # 4-3: “Filtration
and biofiltration systems”
• Information # 4-4: “Determining
pump capacities”
• Information sheet # 4-5: “Powering
life support systems”
• Information sheet # 4-6: “Personal
safety in basic electrical and
plumbing works”
• Information sheet # 4-7: “Basic
electricity”
• Information sheet # 4-8: “Basic
plumbing”
2. Perform job sheet # 4- 1: “Installing the
identified life support system”
3. Answer Self-Check # 4-1. Read Self-Check # 4-1 questions and
4. Check your answers. write down your answers.
Refer to Answer Key # 4-1 and check if
you got the right answers.
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INFORMATION SHEET # 4-1
THE PIPING SYSTEM
Whether you are pumping water to fill a pond or to aerate, it pays to do it as economically
as possible. A key to economical operation is to minimize the work you have to do and to
match your pump to the requirements. Both depend upon the piping system you move
your water through. A suitable piping system for your operation can be determined by
considering the three components that make up the total resistance to water movement in
the pipe. This resistance, called the total dynamic head (TDH), determines the amount
of work required to move each gallon of water. The total dynamic head is the sum of the
lift, the velocity head and the friction head.
TDH = Lift + Velocity Head + Friction Head
• Lift. Lift is the vertical distance between the level of supply water’s surface and
point of discharge at the end of the pipe while the pump is running. It is the only
component of the total dynamic head which is not directly affected by the piping
system.
• Velocity Head. The energy contained in a stream of water due to its velocity. This
energy is lost when the water is discharged. The amount of work required to
produce this velocity is equivalent to picking up the water high enough so that it
would obtain the required velocity in falling. This height is called a “head” and is
commonly measured in feet of water (the height the water has to be picked up).
Numerically, it is equal to the square of the velocity (in feet per second) divided by
64.
Most losses, and the work required to move the water in the pipe, vary with the
velocity head. For a given flow rate, the velocity head is very sensitive to the size
of the pipe. The velocity head depends upon the fourth power of the pipe diameter.
• Friction Head. The friction head is the pressure loss (in feet of water) caused by
friction resistance when water flows through pipe, fittings, valves, etc. This loss is
directly dependent on the length of the pipe and the number of fittings. A pipe twice
as long as another pipe of the same diameter with the same water flow would have
twice the friction loss and require twice the power to overcome the loss. The
friction losses vary approximately as the velocity squared. Thus, like the velocity
head they are very dependent on pipe diameter – the smaller the pipe the more
losses (pressure drop) and the more pumping power required to move the same
amount of water. Friction losses for pipe are quite often given as the loss in feet of
water at a given flow rate for a 100 foot length of pipe. The following tables list
head loss at various flow rates of water for 100 feet of several diameters of pipes.
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The velocity head (in feet) and friction loss (in feet, for 100 ft PVC pipe) for various
diameter pipes and flow rates are given below as reference for computational work:
GPM VELOCITY HEAD (in feet) FRICTION LOSS (in ft; for 100 ft PVC)
flow 4” 6” 8” 10” 12” 4” 6” 8” 10” 12”
0.10 0.02 0.01 0.00 0.00 0.66 0.09 0.02 0.01 0.00
100 0.41 0.08 0.03 0.01 0.01 2.39 0.33 0.08 0.03 0.01
200 1.62 0.32 0.10 0.04 0.02 8.63 1.20 0.30 0.10 0.04
400 3.65 0.72 0.23 0.09 0.05 18.28 2.55 0.63 0.21 0.09
600 6.48 1.28 0.41 0.17 0.08 31.12 4.34 1.07 0.36 0.15
800 10.13 2.00 0.63 0.26 0.13 47.03 6.55 1.62 0.55 0.23
1,000 22.80 4.50 1.42 0.58 0.28 99.57 13.88 3.43 1.16 0.48
1,500 40.53 8.01 2.53 1.04 0.50
2,000 63.32 12.51 3.96 1.62 0.78 169.53 23.63 5.84 1.97 0.81
2,500 91.19 18.01 5.70 2.33 1.13 256.18 35.71 8.82 2.98 1.23
3,000 162.11 32.02 10.13 4.15 2.00 358.94 50.03 12.36 4.18 1.72
4,000 253.29 50.03 15.83 6.48 3.13 611.17 85.18 21.05 7.11 2.93
5,000 569.91 112.57 35.62 14.59 7.04 932.52 128.72 31.80 10.75 4.43
7,500 1013.17 200.13 63.32 25.94 12.51 1955.31 272.53 67.33 22.76 9.38
10,000 3329.29 464.03 114.64 38.76 15.98
A piping system or segments of a piping system may be arranged in series or parallel:
Æ Series pipe means that all the water will have to flow through each section of pipe,
one after the other. The total pressure drop in a series is found by adding the
pressure drop in each section.
Æ A parallel arrangement means that the water may flow in two or more paths. In a
parallel arrangement, the water will divide the total flow so that the total pressure
drop in each path will be the same. The total pressure drop in a parallel
arrangement is found by following one path and adding up all the pressure drops in
that path.
Finding the pressure drop in a parallel path may require a trial and error approach.
A flow rate in each path is assumed so that the total flow in all paths equals the
total flow rate. The pressure drop in each path is then determined. If the pressure
drop in each path is not the same, a new guess for the flow in each path is made
and the pressure drops determined. This procedure is continued until agreement is
reached.
Usually, in aquaculture systems, series analysis can be used since all the water is likely
to be directed to one exit at some time during the operation and this will result in pipe
sizing that is satisfactory under other flow conditions. The following procedure should be
used to analyze your piping system or a piping system you are considering:
1. Determine the required flow rate in gallons per minute (gpm). You may want to
add a safety factor, say 10 percent, to take care of pump wear and pipe aging.
2. Determine the lift in feet.
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3. Choose the diameter of the pipe.
4. Determine the total equivalent length of the pipe. This is equal to the length of the
pipe plus the equivalent length of all fittings.
5. Use the velocity head table and diameter of the pipe at the discharge to
determine the velocity head. (It will not help much to suddenly enlarge the pipe
here because of the losses the enlargement will cause.)
6. Use the friction loss tables to determine the friction loss.
7. If the diameter of the pipe changes, treat each section of pipe of different
diameters separately and then add the total friction losses.
8. Add up the lift, the friction losses and the velocity head. The result is the total
head in feet that the pump will have to supply. The pressure (in psi) the pump
must supply is equal to the total head divided by 2.3.
9. The power a perfect pump (100 percent efficient) would require is called the
water horsepower and is computed as the sum of GPM multiplied by the Total
Head (in feet) divided by 3,960:
Water Horsepower = GPM x Total Head (in feet)
3,960
10. Examine the pressure and power requirements of the piping system. If the
performance is not suitable, try a different design and repeat the steps.
11. Determine the suction required of the pump. The suction required is the sum of
the lift to the pump, the friction head loss from the water source to the pump and
the velocity head. Choose a suitable pump. If no suitable pump can be found,
redesign the piping system.
To illustrate how the analysis of a piping system is done, let’s take the following sample
situation:
It is required to pump 2,000 gpm of water from a source 5 feet
below and 400 feet from the discharge. Three ells and 20
couplings are required in the pipe run. Choose the size of pipe
to use. There is a quantity of 6-inch plastic pipe available.
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Computational Steps 1st Iteration (6” pipes) 2nd Iteration (12”
Determine the required pipes)
GPM; may add 10% 2,000 GPM (No Safety
safety factor Factor) 2,000 GPM (No Safety
Determine Lift in feet Factor)
Choose Pipe Diameter
Determine total equiv 5 ft 5 ft
length of the pipe:
Length of Pipe + Equiv 6” since it is available 12”
Length of all Fittings
Vertical run =5 Vertical run =5
Determine Velocity Head
(refer to Table) ft ft
Determine Friction Loss Horizontal run = Horizontal run =
(refer to Table)
400 ft 400 ft
Provision for diameter
change 3 ells Equiv Length = 3 ells Equiv Length =
Add up the lift, velocity
head, and friction loss to 45 ft 90 ft
get TDH
(3X30X6/12 = 45) (3X30X12/12 = 90)
Determine Water HP
20 couplings = 20 couplings =
Determine PSI
(PSI=TDH/2.3) and 15 ft 30 ft
evaluate in conjunction
with HP requirement. If (20x1.5x6/12 = 15) (20x1.5x12/12 = 30)
not acceptable, try other
options. Total Pipe Length = Total Pipe Length =
Determine Pump Suction
requirement= Lift to 465 ft 525 ft
pump + Friction
From table, Velocity From table, Velocity
Head for 2000GPM for 6” Head for 2000GPM for
= 8.01 ft 12” = 0.50 ft
From table, Friction Loss From table, Friction Loss
for every 100 ft at 2000 for every 100 ft at 2000
GPM for 6” is GPM for 12” is
= 23.63 ft Therefore, for = 0.81 ft Therefore, for
465 ft= 109.9 ft [23.63 x 525 ft= 4.25 ft [0.81 x
(465/100)] (525/100)]
No change No change
Total Lift = 5.00 Total Lift = 5.00
ft Velocity Head = ft Velocity Head =
8.01 ft Friction Loss 0.50 ft Friction Loss
= 109.90 ft Tot Dynamic = 4.25 ft Tot Dynamic
Head = 122.91 ft Head = 9.75 ft
GPMxTDH = 2000 x GPMxTDH = 2000 x
122.91 Product is divide 9.75 Product is divide
by: 3,960 Water HP by: 3,960 Water HP
= 62.1 HP = 4.9 HP
PSI = (122.91/2.3) = 53.4 PSI = (9.75/2.3) = 4.2
psi HP Requirement = psi HP Requirement =
62.1 HP 4.9 HP
TOO LARGE!!! REASONABLE
VALUES
Not Applicable Lift to Pump =
100 ft (Assumed well
depth)
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Loss(water to pump)+ FrictionLoss(12”;100’)=
Velocity Head 0.81 Velocity Head
= 0.50 Pump Suction
Rqmt= 101.31ft
This seems to be a reasonable value, although you may want to try a few more sizes of
pipe and compare the results. Step 11 depends upon the location of the pump, and will
not be considered until a candidate pump is chosen.
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INFORMATION SHEET # 4-2
DETERMINING THE TYPE OF AERATOR SYSTEMS
No one should attempt to be a commercial fish farmer without having aeration devices
and the knowledge of when and how to use them. Aerators can be used exclusively for
emergencies, continuously at night, or all day and night. Aerators work by increasing the
area of contact between air and water. Aerators also circulate water so fish can find
areas with higher oxygen concentrations. Circulation reduces water layering from
stratification and increases oxygen Transfer efficiency by moving oxygenated water away
from the aerator. Many units are electrical, so wiring should be properly protected and
installed to avoid any hazards from an electrical shock.
Aeration and Water Exchange
• How to evaluate an aerator. Aerators are tested to determine the rate at which
they transfer oxygen into water. These tests are conducted in large tanks under
standard conditions with clean tap water at 68° F and no initial dissolved oxygen.
Two terms are commonly used to compare the aerator performance:
o The standard oxygen transfer rate (SOTR) is the amount of oxygen that the
aerator adds to the water per hour under standard conditions and is
reported as lb O2/hr. Ratings for tractor-powered aerators are generally
given as standard oxygen transfer ratings (SOTR).
o The standard aeration efficiency (SAE) is the standard oxygen transfer rate
divided by the amount of power required and is expressed as lbs O2/hr per
horsepower (hp) or lbs O2/hp-hr. Smaller aerators are normally given
standard aeration efficiency ratings (SAE).
Efficiency ratings are based on the horsepower applied to the aerator shaft and not
the horsepower of the power source. Most commercial aerators have ratings
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between 1 and 5 lbs O2/hp-hr. Test results of different aerators can be compared
in selecting an effective and energy-efficient unit. Some manufacturers test their
own equipment. When comparing test results, it is important to know if test
conditions were standardized. Also, an aerator may have a high oxygen transfer
rate with low efficiency rating. Cost of operation should be less for a more efficient
aerator.
• Types of aerators. Fish farmers have used emergency aerators powered by
tractor power takeoffs (PTOS) for many years. With production intensification and
the increasing need for aeration, these PTO aerators can be quite expensive
because each aerator requires a tractor. Therefore, more electric aerators are
being used than ever before. Large tractor-powered aerators are still used as
back-ups during severe oxygen depletions, equipment failure, or power outages.
Each producer decides which aeration device should be purchased or built. This
decision is important and should be made with the specific application and
associated costs of energy and equipment in mind. Several types of aeration
devices have been evaluated for use in commercial fish ponds. Most aerators are
in one of the following categories:
o Surface spray or vertical pump. Surface spray aerators have a submersible
motor which rotates an impeller to pump surface water into the air as a
spray. They float, are lightweight, portable and electrically powered. Units
of 1 to 5 hp with pumping rates of 500 to 2,000 gpm are available.
They are designed to be operated continuously during nighttime, cloudy
weather, or when low dissolved oxygen concentrations are expected.
Surface spray aerators have prevented fish kills when used at 1.5 to 2
hp/acre. They are usually of little use in large ponds, because of relatively
low oxygen transfer rates and their inability to create an adequately large
area of oxygenated water.
o Pump sprayer. Pump sprayer aerators are found on many fish farms. Most
are powered by a tractor power takeoff or electricity. Some units are engine
driven and require mounting on a trailer frame for transport. Pump sprayer
aerators are equipped with either an impeller suction pump, an impeller lift
pump, or a turbine pump. Some have a capped sprayer pipe or “bonnet”
with outlet slits attached to the pump discharge. Others discharge directly
through a manifold which has discharge slits on top and outlets at each end.
Water is sprayed vertically through the discharge slits and from each end of
the manifold. This type is commonly referred to as a T-pump or bank-
washer and directs oxygenated water along a pond bank where distressed
fish often go. Pump sprayers typically have no gear reduction which
reduces mechanical failure and maintenance. These units do not erode the
pond bottom, and minimum operating depth is reached when the intake is
covered with water.
o Paddlewheel aerators. Paddlewheel aerators have been used on catfish
farms for many years. Farm-made paddlewheels are usually made from 3/4
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ton truck differentials and vary with drum size and configuration, shape,
number and length of paddles. Units are powered by power takeoffs or
driven by self-contained diesel engines. The self-contained units are usually
on floats and attached to the pond bank or held in place by steel bars
secured in the bank or pond bottom.
Speed and Depth. Studies have demonstrated that increasing either
the speed of the drum rotation (rpm) or paddle depth generally
increases aeration capacity. Paddle depth affects oxygen transfer
rates more than does the speed of rotation. This increase in capacity
is not cost free, because horsepower requirements increase and
oxygen transfer efficiency may decrease. The maximum rotational
speed of a tractor-powered paddlewheel aerator for extended
operation is limited by the tractor, its recommended power takeoff
speed under load, and the gear reduction of the paddlewheel.
Shape of Paddles. The shape of the paddles is also important; for
example, U, V, or cup shapes are more efficient designs than flat
paddles. Paddlewheels create vibrations that can be reduced when
paddles are arranged in a spiral pattern. The oxygen transfer rate
and power requirement increase with paddle immersion depth and
the diameter of the paddlewheel drum. The size of the spray pattern
likewise increases. The power required to operate a paddlewheel
aerator at any given speed and paddle depth is constant. Fuel
consumption and operating costs depend on the power source.
o Electric paddlewheel. Electric paddlewheel units are 4 to 12 feet long with
paddles of triangular cross section and a total drum diameter of about 28 to
36 inches. Paddlewheel speed is usually 80 to 90 rpm with a paddle depth
of about 4 inches, enough to load the motor. The correct paddle depth can
be determined in the field as the depth needed to draw the rated amperes of
the motor. To extend the service life of the motor, the motor should draw
only 90 percent of full load amperes rating, unless the manufacturer
recommends differently. Motor sizes range from 1/2 hp to 19 hp and larger.
Motors operating on single or three-phase current are available.
Methods used to reduce the motor speed to the desired aerator shaft speed
include v-belts and pulleys, chain drive and gears and gearboxes. Shafts of
most electric motors run at 1,750 rpm and most units are mounted on floats.
o Diffused air systems. Diffuser aerators operated by low pressure air
blowers or compressors forcing air through weighted aeration lines or
diffuser stones release air bubbles at the pond bottom or several feet below
the water surface. Efficiency of oxygen transfer is related to the size of air
bubbles released and water depth. The smaller the bubble and the deeper it
is released, the more efficient this type aerator becomes. When tested at
normal catfish pond depths, these aerators were found to be inefficient
compared to other devices.
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Limited studies in commercial catfish ponds showed no improvement in fish
production when a diffused aeration system was used. One of the biggest
problems with diffused-air systems is clogging of the air lines and diffusers
so that periodic cleaning is required. Also, the air lines interfere with
harvesting.
o Propeller-aspirator pump. These aerators consist of a rotating, hollow shaft
attached to a motor shaft. The submerged end of the rotating, hollow shaft
is fitted with an impeller which accelerates the water to a velocity high
enough to cause a drop in pressure over the diffusing surface which pulls
air down the hollow shaft. Air passes through a diffuser and enters the water
as fine bubbles that are mixed into the pond water by the turbulence created
by the propeller. They are electrically powered, and models range from
0.125 to 25 hp.
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INFORMATION SHEET # 4-3
FILTRATION AND BIOFILTRATION SYSTEMS
While aeration can compensate for the water exchange in providing adequate DO, it does
very little in eliminating harmful elements and particles in the water that is caused by
excretions and natural growth and decay processes in the water. Because of this, the
use of filtrations and biofiltrations in a re-circulating system is becoming very popular in
aquaculture.
In aquaculture, filtration and biofiltration are very distinct and separate entities and they
must be treated as such.. There are three (3) forms of aquaculture wastes:
Æ Solid waste is typically categorized by its size and specific gravity.
Settleable solids are those solids which have a relatively high specific
gravity compared to the water in which they exist. They will settle to the
bottom.
Æ Suspended solids are those in a category which have a specific gravity the
same as or slightly higher than the water. They tend to stay in suspension
and will only "drop-out" over a long period of time. Dissolved solids are
those which actually become a part of the water.
Æ The dissolved solids are eliminated by reverse osmosis, anion and cation
resins, activated carbon, etc.
• Filtration. Filtration is the removal of solid and suspended wastes. The methods
of filtration ranges from sedimentation tanks, screen mesh to sieve particles, to the
use of materials that “statically” attracts suspended particles.
o One method of removing solid waste from a round fish tank is to use a
double drain. It will direct the settled solids to a separate area from the
suspended solids. The settled solids can be directed into a small clarifier,
much smaller than one which had to be sized to handle the entire flow of
re-circulating water. The other drain takes the suspended solids along with
the nitrogenous waste.
o Suspended solids can be removed by several methods. One is the affinity
bead filter which incorporates the use of small polyethylene beads that have
an electrostatic charge. These beads have an affinity for the negatively
charged suspended solids. As the particles pass these beads, they are
"statically" drawn to them. When the beads are loaded with solids, it is time
to backwash them. (Too often, backwashing is not done frequently enough.)
Suspended solids can also be removed by mechanical means such as bag
filters, drum filters and vegetable filters.
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• Biofiltration. Biofiltration is the aerobic (with oxygen) breakdown of dissolved
nitrogenous fish waste (ammonia). Fish will excrete about 14 grams of ammonia
for each pound of food eaten (at 35% protein). The nitrification of ammonia is
accomplished by two strains of autotrophic bacteria. These bacteria are naturally
occurring and will ultimately colonize the bio-media in your biofilter as well as the
tank walls etc. The speed of this process is dependent on temperature, pH,
salinity surface area, flow rate, etc.
Biolfiltation makes use of biofilter media. These media are merely masses of
surfaces serving as the attachment basis for micro-organisms. The spacing
between these surfaces is important, both for the passage of water and to provide
sufficient room for bacterial growth. Balls, Bio Strata, Bio-Fill, scrub pads, and
even sand can be used as biofilter media. It is recommended that you use
approximately 300 sq. ft. of surface area per 100 lbs. of fish in a warm water
recirculating system. To give a general idea, these manufactured media range
from 26-370 square feet of surface area per every cubic foot of media. Another
general rule of thumb is having the volume of the biofilter to be around 15% of the
total volume of the system.
• Stages of Filtration Systems. Regardless of which type of filtering equipment
you decide to use, the important thing to keep in mind is to always stage your
filtration. It is an all too common mistake to design a system that relies too heavily
on a single filtering device to provide all of the filtering demands that a re-
circulating system has. By staging your filtration, you will find your system
performing at or near its peak.
o Sedimentation - removal of solid wastes from the water:
1. Do whatever is possible to allow fish feces to drop intact into the
waste collection area or self cleaning bottom with minimal damage.
Minimize the use of pumps, aerators and air diffusers wherever feces
are present.
2. Do not pump the waste prior to separation. Design for gravity flow (or
siphon) into a sedimentation tank or basin. Splashing and turbulence
can attach air bubbles and break apart solids. Feces and food
particles smaller than 40 microns may not settle without chemical
flocculants.
3. Always locate your biofilter after the solids removal system. Solids
provide carbon for heterotrophic bacteria which can foul a biofilter
and/or reduce its performance.
4. Clean both the settling area and filters at least once a day even if
they contain little waste.
5. If further filtration is required after sedimentation, pump the water to
an affinity bead clarifier or particulate filter.
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o Mechanical entrapments or beads. Mechanical entrapments act like a net
or a filter cloth that allows the liquid to pass but not the solids. On the other
hand, bead filtration utilizes an electrostatic attraction to draw particles out
of the water.
Even as biofilter media can be incorporated at any point in the system,
many practitioners locate this biofiltration material as part of the mechanical
entrapment filters. Biofilters are merely "surfaces" which are "fed" water
containing ammonia. The "surfaces" include the inside surfaces of the water
pipes and fish tanks and the biofilter media, the beads in the bead filter, a
sand filter and a fluidized bed filter. After a period of time, the surface will
develop a slimy layer of nitrosomonas and nitrobacter bacteria. The
population of these bacteria will continue to multiply until their population
becomes proportional to their food supply: ammonia and nitrite.
o Degassing - removal of dangerous gasses from the water:
Degassing is a process which is used to remove undesirable gasses, that
are present in greater concentrations in the water than would otherwise
naturally be found. When they are in this state, such gasses are called
supersaturated gasses. When exposed to an interface between air and
water, supersaturated gas has a natural tendency to escape out of the
water and into the surrounding air. The main function of a degasser is to
create a large interface between the water and the air. This is achieved in a
variety of ways. One way is by heavy aeration, where the surface area of
the bubbles creates a large interface as they rise through the water.
Aeration also creates a lot of turbulence, bringing water to the surface
where the gas can escape directly to the atmosphere. Another degassing
method is letting the water fall over weirs and cascades, where it is broken
up into droplets, thereby increasing the interface. Also commonly used are
packed columns, which are vessels filled with a type of media over which
the water runs.
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INFORMATION SHEET # 4-4
DETERMINING PUMP CAPACITIES
In order to obtain a pumping system that will meet your requirements, and meet them in
an efficient manner, you must match the pump to the piping system and required flow
rate. A cost analysis of pumping will consider initial cost of capital investment, annual
fixed cost and operating cost. All three costs are somewhat dependent on each other.
The type of pumping equipment, size of pipelines, size of pumps and type of water supply
affect not only the initial cost but also the fixed cost as well as the operating cost. For
example, piping systems using large pipes may cost more but could allow the use of
smaller horsepower pumps which cost less, require smaller power sources and cost less
to operate than a piping system with small diameter pipe. The lowest priced system is
not always the best buy, especially if the lower price means less efficient pumps. To get
the most efficient pump, an analysis should be made of all pumping requirements.
• Cetrifugal Pumps. Pumps used in aquaculture often are a form of the centrifugal
pump. Two basic types of centrifugal pumps are horizontal and vertical. As the
name implies, centrifugal pumps use centrifugal force to move water from one
point to another and to overcome resistance to its flow. In its simplest form, this
pump consists of an impeller fixed on a rotating shaft within a volute-type (spiral)
casing. Water enters at the center of the impeller and is forced to the outer edge at
a high velocity by the rotating impeller. The water is discharged by centrifugal force
into the casing where the high velocity head is converted to pressure head.
o Horizontal centrifugal pumps (for surface supply and shallow wells).
Horizontal centrifugal pumps are frequently used if the source of water is a
surface supply, such as a lake, stream, canal or pond, or a shallow well. A
shallow well, as opposed to a deep well, is one in which the water level in
the well is high enough to permit the vacuum at the pump to lift the water
and keep it flowing at an acceptable rate. As the name implies, horizontal
centrifugal pumps normally have a horizontal shaft.
This type of pump is usually subdivided into two groups, single suction (end
suction) and double suction (often called split case). Either of these may be
single or multistage; that is, they may have only one impeller or they may
have two or more impellers. These impellers are so constructed that the
water, in passing through the pump, is conducted from the discharge of one
impeller to the suction of the second; thus, the total head is that developed
by a single impeller multiplied by the number of impellers in the pump. The
most common pump and the lowest in cost is the end suction, single stage.
Jet pumps. A jet pump is often used for very low capacity
requirements (5 to 20 gpm), such as a home water system. This
pump consists of a small centrifugal pump located at ground level
connected to a jet installed below the water level in the well (Figure
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4). By circulating part of the water from the pump back through the
jet, water is forced up to the impeller in the pump, and a continuous
flow at reasonable pressure is provided. Shallow-well jet pumps
operate on the recirculation principle, but the jet is installed above
ground and the allowable lift is limited to about 22 feet. Deep-well jet
pumps, however, have a maximum lift of about 65 feet. Jet pumps
are designed for home water systems, and their capacities are
seldom adequate for aqua-cultural purposes. Also, the jet pump
requires about twice the horsepower that a submersible requires to
deliver the same amount of water from the same depth.
Axial flow propeller pumps. Axial flow propeller pumps are designed
to operate efficiently for aquacultural, irrigation or drainage pumping
at low head and high volume (more than 500 gpm). Their efficiency is
high, especially when the total head is in the range of 8 to 20 feet.
The pumping element of an axial flow propeller pump consists mainly
of a revolving propeller in a stationary bowl which contains vanes
above and below the propeller. Water enters the pump through the
intake bell. It is discharged into the distributor section and then out
the discharge elbow. Flowing in essentially a straight line along the
pump axis keeps friction and turbulence to a minimum. The propeller
of an axial flow pump must be submerged in the source of water.
One of the advantages of this pump is that it will handle some debris.
o Deep well vertical turbine pumps. For a deep well, the most widely used
pump is a vertical centrifugal, commonly referred to as a “deep well turbine.”
Basically, this is a centrifugal pump designed to be installed in a well. It will
not handle debris.
Because of the limited diameter of its impellers, each impeller develops a
rather low head, and it is necessary in the average application to stack
several impellers in series one above the other with each in its own bowl or
diffuser housing. This is called staging. Thus, a four-stage bowl assembly
contains four impellers, all attached to a common shaft through the separate
housing or bowls. The bowl shaft is attached to the line shaft through the
center of the pump column pipe and must be long enough to locate the bowl
assembly below the level of the water in the well when pumping at required
capacity.
Water/Oil Lubricated Turbine Pumps. Water-lubricated turbine
pumps are simpler, cheaper and more commonly used. If more than
four or five of the rubber shaft bearings are above the water level and
become dry when the pump is not operating, some means of pre-
lubrication, such as a small pre-lub tank from which water can be
spilled over the bearings before starting the pump (Figure 6), is
required. With smaller pumps, a foot valve can be installed below
the bowl assembly to keep the column pipe full of water. Because of
friction loss, it is impractical to use a foot valve for applications
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requiring large flows.
When the water level is very deep, oil lubrication is normally used.
Although there is no definite point at which it becomes necessary, it
is usually recommended for depths of more than 150 to 200 feet.
Submersible Pumps. The submersible pump consists of a multistage
vertical turbine pump connected directly to an electric motor
designed to operate under water. Both the pump and motor are
suspended in the well below the water level by a pipe that conducts
the water to the surface. This type is available in a wide range of
capacities for 4-inch wells and larger. Most submersible pumps used
for aquaculture require three-phase electrical service.
• Basic Considerations in Selecting Pumps. If you must lift water, reducing the
lift will improve the overall efficiency of operation. Surface sources of water usually
require much less lift than pumping from wells. Two common types of pumps
designed primarily for low-lift operations are the propeller axial flow pump and the
horizontal PTO-driven centrifugal pump. Axial flow propeller pumps have very high
efficiencies and are capable of pumping large volumes. Horizontal centrifugal
PTO-driven pumps are less efficient but still maintain the capability of pumping
large volumes of water. They also are portable and often fit into a flexible
management plan for aquaculture production.
o Pump efficiency. Selecting a correct pumping plant not only will conserve
valuable energy supplies but also will reduce total annual pumping costs.
Inefficient pumping plants can increase costs dramatically. The efficiency of
a pump is a measure of the degree of its hydraulic and mechanical
perfection. Pump efficiency is the ratio of the output water horsepower to
the input shaft horsepower expressed as a percentage: A horsepower is
defined as the power required to raise a weight of 33,000 pounds a vertical
distance of 1 foot in 1 minute. The rate of work performed by a pump (in
horsepower) is proportional to the weight of the water it delivers per minute
multiplied by the total equivalent vertical distance in feet through which it is
moved.
o Well size and capacity limits. There are definite capacity limitations for a
given diameter of well casing. To obtain this limit, the pump must have
sufficient capacity. The capacity of a centrifugal pump varies directly with
its speed of operation. It may be necessary to increase the pump speed to
get maximum capacity from a given well size. Maximum permissible speed
depends upon a number of factors, but for 4-inch, 6-inch and even 8-inch
pumps, a speed of 3,600 rpm is not uncommon. For larger sizes, however,
this speed is not advisable. Since nominal electric motor speeds used in
pumping are either 1,760 rpm or 3,450 rpm, intermediate speeds may be
achieved with right-angle gears of suitable ratio or with belt and pulley
drives.
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o Pumping from a well. Changes in pumping heads because of different
operating systems usually require a change in the pumps to maintain
greatest efficiency.
Does your pump surge? If you observe a surge in the discharge, the pump
may be having difficulty getting enough water. Assuming that adequate
water is available to flow into the well and that encrusted wells are not the
problem, then the surge is normally caused by the pump not being
submerged enough to provide water for intake. Where the pump is located
some distance from the bottom of the well, it is often possible to lower the
pump and reduce the amount of surging. This can require more power
since full water flow may be obtained along with higher head. This may
overload the existing motor. In some instances you may have to add
another stage and change the motor to one of greater horsepower.
When the pump is set near the bottom of the well and it is impossible to
lower the pump to minimize surging, consider other alternatives. Long-term
solutions resulting in higher efficiency include pulling the pump and trimming
the impeller or replacing the pump with a different pump of a smaller
capacity. It might also be possible to decrease the pump speed and thus
decrease the amount of water which is pumped, but this could result in a
sizable decrease in efficiency. These short-term solutions for a single
pumping season will result in a decrease in efficiency; adjustment of the
impellers upward, throttling of the discharge by closing a valve on the
discharge side, and, for belt-driven pumps, the exchange of pulleys in such
a way to decrease rpm.
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INFORMATION SHEET # 4-5
POWERING LIFE SUPPORT SYSTEMS
The choice of a power source for aqua-cultural production is a choice between electric
motors and internal combustion engines. In some instances a combination of electric
motors and generators powered by internal combustion engines may be used. Each
power source has its advantages and disadvantages, many of which are site and
application dependent. Which type of power plant you use will depend upon your
particular situation and preferences; however, you should consider the following factors
before making your decision:
Æ Ability to do the job;
Æ Reliability of power source and fuel supply;
Æ Initial cost of equipment and installation;
Æ Expected useful life;
Æ Convenience of operation and ease of maintenance;
Æ Procurement, current operating, and future costs; and
Æ Safety.
• Internal Combustion Engines. Internal combustion engines supply a significant
percentage of power for aquaculture operations. This is largely due to the
scattered nature of power needs which may make a low-cost electric power source
(electric service) unattainable. Diesel, gasoline, and LPG engines can be supplied
with fuel from storage tanks which allows considerable freedom in locating the
power plant.
The speed of internal combustion engines may be adjusted if needed (although
efficiency may suffer), giving them more flexibility in this respect than electric
motors. On the other hand, internal combustion engines are sensitive to their duty
cycle. Cycles of short duration with lengthy off cycles are particularly detrimental to
their performance and longevity because of substantial running time under cold-
engine conditions. In general, internal combustion engines are best suited to
higher horsepower applications with high annual hours of use. Fuel efficiency is
usually better for higher horsepower engines (properly matched to load), and the
higher fixed cost can be spread over more operating hours.
Hereunder are some bases for selecting the right type of engine:
o Continuous Service Rating. Base your selection of an engine as a power
source for pumping or similar applications requiring long run times on the
continuous service rating rather than on the maximum brake horsepower
(bhp) rating. Be aware that many engines are tested without components
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such as alternators, radiator fans or water pumps.
o Engine Sized for the Load. An engine may show substandard performance
if it is not loaded properly. Diesel, gasoline and propane engines should be
sized to the load, whether the load is a generator or an aerator. Properly
sizing the power source can improve fuel efficiency.
o Proper Maintenance. The engine should be maintained in good operating
condition. Ignition, timing and carburetion should be adjusted on spark-
ignited engines. Diesel engines require fuel injection timing. Have a
qualified specialist make adjustments to ensure the greatest efficiency
under the operating conditions. An additional consideration for diesel,
gasoline and LPG engines is fuel storage. Storage tanks should be
designed to prevent pollution and, if a leak or spill occurs, to permit cleaning
up the fuel.
• Electric Motors. There are obvious advantages of electric motors if the energy
and standby charges are not prohibitive. The electric motor provides ease of
operation (flip a switch to start), and long life, requires minimal maintenance and
maintains its performance level year after year. In addition, initial costs are usually
less than the cost of internal combustion engines. Reliability of electric motors is
higher than that of internal combustion engines; however, they can be shut down
by the loss of electrical power. This may be a deciding factor if you live in an area
that has frequent power losses or you cannot tolerate a loss of power.
The amount of power needed is one of the first points to consider. Motors of five
horsepower or less can be powered from the usual 220 volt single-phase current
supply. Larger motors usually require three-phase, 220 or 440 volt current. As a
rule, electric motors need not be rated from the horsepower indicated on the
nameplate. An electric motor should be selected to operate at nearly full load
since the motor efficiency is lower when under-loaded (particularly at 50 percent or
smaller load). Standby and energy costs are also higher than necessary when the
motor is under-loaded. However, you should not overload the motor. If motor
requirements fall between motor sizes, select the larger motor. For example, if
power required is 34 hp, choose the 40 hp motor rather than the 30 hp one.
Electric motors vary in efficiency of converting electric energy to mechanical
energy. Motors in the 15 to 40 hp range average about 86 percent efficiency; in the
50 to 150 hp range, they average about 90 percent efficiency.
• Important Considerations in choosing the power plant:
o Fuel costs. One of the biggest costs of a power plant that operates many
hours is the cost of the fuel. In order to estimate this cost, the performance
of the power plant must be known. Manufacturers have performance data
for their products. The fuel economy can be expressed in several ways.
Electric motors and some internal combustion engines use efficiency. For
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other internal combustion engines, fuel economy is expressed in terms of
power and amount of fuel used. For example, gallons per hp hour and
pounds of fuel per hp hour may be used to express an engine’s fuel
economy. This method is often denoted as Brake Specific Fuel
Consumption (BSFC).
o Maintenance costs. Maintenance costs are considerably higher for internal
combustion engines than for electric motors. The exact costs are difficult to
pin down as they depend on duty cycle, cost of labor and degree of
maintenance. However, a rough rule of thumb is to assess internal
combustion engines a one cent per horsepower-hour maintenance cost
penalty in comparison with electric motors.
o Safety. Your first priority should be safe working conditions and safe
working practices. Safety is important. Make certain all safety guards are
in place and in good condition, especially on PTO shafts and stub gear.
Perform any inspection or service only after equipment is shut down. Refuel
only when engine is not operating and is cooled down. Make sure that
tractor operators are experienced, especially when equipment is used on
levees and around ponds. When using tractors to relocate or place aeration
equipment, set brakes securely and block wheels.
Handle fuel with caution. Do not smoke around fuel. Use a vent on your fuel
storage tank and make sure the tank is grounded. For electrical safety, do
not drive over wires. This can damage the wire’s insulation. Make sure that
power is shut off and locked out at the control box before any maintenance
work is done.
Use qualified electricians to install wiring and avoid a jury-rigged job. Use
only approved wiring and follow applicable electrical codes. Your local
electrical inspector, supply house, electrician or power supplier may be able
to advise you. To prevent rodents from damaging any wiring, place exposed
wiring in conduits.
Electric Blower Pressure Blower
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INFORMATION SHEET # 4-6
PERSONAL SAFETY IN BASIC ELECTRICAL AND PLUMBING WORKS
Safety is of utmost importance when working with electricity. Develop safe work habits
and stick to them. Be very careful with electricity. It may be invisible, but it can be
dangerous if not understood and respected.
Safety glasses or goggles should be worn whenever power tools are used,
especially if you wear contact lenses.
Make sure the power is off at the breaker box before doing any electrical work
Always work in a dean, dry area free from anything wet.
Wires should only be connected at accessible junction boxes. Never splice wires
together and conceal them within a wall without a junction box.
Never attempt to strip wires with a knife. Aside from endangering your fingers, you
will nick the wire metal, which will create an electrical hazard.
Ground fault circuit interrupter out- lets should be used under damp conditions
(basements, bathrooms, out- doors, etc.), as required by the National Electric
Code.
Don't create fire hazards by over- loading an outlet or an extension cord.
Avoid electrical shock by mapping and marking your switch and outlet boxes. Put
the map on the door of the main power service panel.
Leave a warning message that you are working on the circuit at the service panel,
and tape the circuit breaker in the off position. With a fuse box, take the fuse out
Never change the size of a fuse or breaker in a circuit.
Be certain your connector is CO/ALR rated when you splice aluminum wire. If it is
marked CU/ALR, use only copper wire. Do not use aluminum wire with push
terminals; use only copper or copper-dad aluminum wire.
Always correct the problem that caused a fuse or circuit breaker to blow before
replacing the fuse or circuit breaker.
Replace wiring that shows signs of fraying or deterioration.
Avoid breaking your knuckles by bracing the powerful right-angle drill so that it
cannot spin around if it gets stuck while drilling.
Before working with wires or electrical connections, check them with a voltage
tester to be sure they are dead.
Plumbing and gas pipes are often used to ground electrical systems. Never touch
them while working with electricity.
Don't use metal ladders with over- head electricity.
Use the proper protection, take precautions, and plan ahead. Never by-pass safety
to save money or to rush a project
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INFORMATION SHEET # 4-7
BASIC ELECTRICITY
Electricity can be an intimidating concept for many because of the potential danger. You
can virtually eliminate that danger with a little knowledge and proper safety practices.
However, regardless of how much knowledge you have, never become lax in dealing with
an electrical system, or it can be deadly.
The information in this section is meant to give you an understanding of several common
electrical situations that you might encounter. Because of the many options and variations
in this area, it is not intended to be a complete guide to electrical work. Never take
chances with electrical work If you feel you need more information, consult an electrician
or a more detailed reference book if you plan any extensive electrical work, it is
recommend that you seek a professional.
• Useful Terms. Here are some useful terms in electricity:
o Ampere. Measures the number of electrically charged particles that flow
past a given point on a circuit (per second).
o Breaker box (breaker panel). Houses the circuit breakers or fuses,
distributes power to various parts of your house.
o Circuit. All wiring controlled by one fuse or circuit breaker.
o Circuit breaker. Protective device for each circuit, which automatically cuts
off power from the main breaker in the event of an overload or short. Only a
regulated amount of current can pass through the breaker before it will
"trip."
o Main breaker. Turns the power entering your home through the breaker box
on or off. This is sometimes found in the breaker box, or it may be in a
separate box and at another location.
o Roughing-in. Placement of outlets, switches and lights prior to actual
electrical hook-up.
o Volt. Measures the current pressure at receptacles and lights. Average
household voltage is 120.
o Watt. The rate at which an electrical device (light bulb, appliance, etc.)
consumes energy Watts=volts x amps.
• Common Tools Used. There are some special (although inexpensive) tools
required for use with electricity.
o Long-nose (needle-nose) pliers
o Wire cutters
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o Electric drill
o Screw drivers
o Cable stripper
o Wire stripper
o Colored tape
o Voltage tester
o Continuity tester
o Right-angle drill, which can be rented.
o Other tools from your household toolbox that may include tape measures,
hammer, hacksaw, utility knife, etc.
• Permits and Codes. Always consult the office of your local building inspector to
determine what permits or special provisions must be met. All electrical work
must pass local codes, no matter how small the job. Be sure to get the proper
permits, and be certain that you are dear on how to do your work so that it will
pass code. Local codes may differ; check with your local building inspector.
Some of the work may need to be done by a licensed electrical contractor. Never
are inspectors more fearful of unqualified people doing their own work than with
electrical systems. The chances for electrocution, or a structural fire resulting from
faulty wiring, are great inspectors check electrical work very carefully. And they
should. So be sure all work is done neatly, to code, and in the manner inspectors
are used to seeing it done.
• Design. A successful wiring project requires a plan so that you know exactly
where you want your outlets, switches, and fixtures to be placed.
Whether you are adding a room or rewiring an old one, don't skimp on the
receptacles. Aside from it being dangerous to overload outlets with extension
cords and adapters, it can be just plain frustrating to have dark corners where you
most need the light. Code usually requires 12' or less between outlets on the same
wall In this way, 6' cord on an appliance or lamp can always reach an outlet
without an extension cord. It will look better if you plan your outlets all to be at the
same height Again, this may be determined by local code.
If there are two entrances to the room, plan for a light switch at both doors. Place
switches on the unhinged side of the door. Determine the most direct route for
fixtures, and route them accordingly. Draw a rough floor plan and note the location
of all receptacles, switches, and fixtures. Such a plan will assist you in making up
your materials list and in calculating the amount of cable you will need.
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• Most Common Mistakes. While it is easy to make mistakes when working with
electricity, it is just as easy to avoid them. The single most important mistake to
avoid is neglecting to turn off the power before beginning. Other mistakes include:
o Not making a plan for the work being done.
o Overloading circuits by plugging too many appliances into an outlet, or by
using an inadequate extension cord.
o Not using UL approved materials.
o Routing the wiring in an inefficient manner.
o Mounting outlets and switches without assuring that they are flush with the
final wall covering.
o Not using the correct junction box for the wiring to be installed.
o Not using weatherproof boxes for outdoor fixtures.
o Neglecting to seal around holes drilled through exterior walls.
o Forgetting to add nail guards where needed.
o Not having your work inspected at critical points
o Neglecting to follow local code.
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INFORMATION SHEET # 4-8
BASIC PLUMBING
• Common Tools. Among the commonly used tools in plumbing jobs are:
o Pipe Wrenches. Usually used in pairs, these large adjustable-end
wrenches specialize in assembling and disassembling round metal
materials such as pipes. For general plumbing repairs, 10- and 18-inch
sizes are good choices.
o Tubing Cutter. An alternative to using a hacksaw, a tubing cutter
progressively scores copper tubing to make clean cuts without squashing or
squeezing. It also includes a reaming blade for removing potentially leak-
causing burrs from the inside edges of the cut pipe.
o Hacksaw. This fine-toothed saw with a replaceable blade will cut a variety
of materials, but its specialty is metal. Mount the blade in the adjustable
holder so the teeth slant forward to cut on the push stroke.
o Miter Box. A miter box is a saw guide that lets you make accurate cuts at a
variety of angles. Simple wooden miter boxes have slotted saw guides at
90- and 45-degree angles. More elaborate metal miter boxes are adjustable
to cut at any angle and often include a miter saw.
o Utility Knife. A toolbox staple, this tool cuts ceiling tiles, vinyl flooring, and a
host of other materials. Specialty replacement blades are available for other
cutting tasks. For safety's sake, buy a knife with a retractable blade.
o Tape Measure. A tape measure consists of a flexible metal blade that
retracts into a compact case. Available in lengths up to 50 feet, some
models include a window in the top of the case that facilitates taking
readings for inside measurements.
o Emery Cloth. Available in coarsenesses of fine, medium, coarse, and extra-
coarse, emery cloth is a durable abrasive used to clean, roughen, and
polish metals.
• Choosing the Type of Pipe. For supply lines -- the pipes that carry pressurized
water to your fixtures -- the usual choices are galvanized iron and plastic. When
making final connections to a fixture or a faucet, usually it is easiest to install a
flexible supply line. Use copper or plastic flexible tubing. Be careful to avoid kinks.
Plastic pipe -- either PVC or ABS -- is now used almost exclusively for supply lines
and drains. If you have old cast-iron, galvanized, or copper drain pipes, make the
transition to plastic. It is much easier to install and less expensive.
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o Working with threaded Galvanized Steel Pipes. Because it is cumbersome
to work with and tends to build up lime deposits that constrict water flow, it
is not used widely anymore. It takes expensive equipment to cut and thread
it, so you must buy pre-cut pieces from your supplier. If you have a good
selection of shorter pieces on hand, you can cut down on trips to the
supplier.
Assembling the parts. This typical installation combines standard-
length pipes with joints and nipples to end up exactly at the right
location. (For background on measuring pipe accurately, see
Measuring Pipes and Fittings, Related Projects.) Many plumbing
suppliers have ready-cut galvanized pipe in standard sizes -- 12
inches, 48 inches, and so on -- for less cost and delay than having
pieces custom-cut. Try to use these pieces; if you make a mistake in
measuring, you may not be allowed to return a custom-cut piece.
Joining the pieces. Before you thread a pipe and fitting together,
seal the pipe threads using pipe joint compound or Teflon tape.
Assemble the pipes and fittings one at a time, tightening each as you
go. If your assembly requires a union, work from each end toward the
union. The union is installed last. Support runs of threaded pipe at
least every 6 feet.
o Working with Plastic PVC Pipes. Plastic plumbing is popular because it is
inexpensive and easy to work with. Plastic pipe cuts with an ordinary
hacksaw, and goes together without special tools or techniques. You simply
clean the burrs from the cut, prime, and glue the parts together. Still,
installing plastic pipe requires attention to detail, planning ahead, and doing
things in the right order. If you make a mistake, the parts cannot be
disassembled. You'll have to cut out the faulty section, throw it out, and start
again.
Measure and cut. When measuring pipe for cutting, take the socket
depth of the fitting into account (see Measuring Pipes and Fittings,
Related Projects). Cut with any fine-tooth saw, using a miter box.
Avoid diagonal cuts because they reduce the bonding area at the
deepest part of the fitting's socket -- the most critical part of the joint.
Remove burrs from the cut end. After you've made the cut, use a
knife or file to remove any burrs from the inside and outside of the cut
end. Burrs can scrape away cement when the pipe is pushed into the
fitting, seriously weakening the bond.
Test the fitting. Dry-fit the connection. You should be able to push it
in at least one-third of the way. If the pipe bottoms out and feels
loose, try another fitting. Unlike copper components, plastic systems
are designed with tapered walls on the inside of the socket so that
the pipe makes contact well before the pipe reaches the socket
shoulder.
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Mark for alignment. When gluing the pieces together, you will have
less than a minute to correctly position the pipe and fitting before the
glue sets. Draw an alignment mark across the pipe and fitting of each
joint. When you fit the pieces together, the mark will indicate exactly
how to position the pipe and fitting.
Mark for alignment. When gluing the pieces together, you will have
less than a minute to correctly position the pipe and fitting before the
glue sets. Draw an alignment mark across the pipe and fitting of each
joint. When you fit the pieces together, the mark will indicate exactly
how to position the pipe and fitting.
Clean and prime. Wipe the inside of the fitting and the outside of the
pipe end with a clean cloth. If you are working with PVC or CPVC
(but not ABS), coat the outside of the pipe end with a special primer.
Many inspectors require purple-colored primer so they can easily see
that joints have been primed.
Apply cement to pipe. Use the cement designed for the material
you're working with. Immediately after you've primed, swab a smooth
coating of cement onto the pipe end.
Prime and cement fitting. Repeat the process on the inside of the
fitting socket. Apply cement liberally, but don't let it puddle inside the
fitting. Reapply a coating of cement to the pipe end.
Twist and hold. Forcefully push the two together to ensure the pipe
moves fully into the socket. Twist a quarter turn as you push to help
spread the cement evenly. Complete the twist until your alignment
marks come together. Hold the pipe and fitting together for about 20
seconds while they fuse into a single piece. Wipe away excess
cement.
Cut off any incorrect joints. If you misalign a connection, saw it off,
making sure to cut squarely. Install a new fitting with a spacer and
slip coupling as shown. Cemented joints are strong enough to handle
after 15 minutes, but don't run water in the line for about two hours.
• Measuring Pipes and Fittings. Beginning plumbers often spend more time
running back and forth to their supplier than they spend doing the actual work
because it takes practice and experience to be able to figure out everything you
need ahead of time. The first step in becoming an efficient plumber is to learn to
correctly identify the pipes and fittings a job requires.
Plumbing dimensions aren't always what they appear to be. A plastic pipe with a
7/8-inch outside diameter, for instance, is actually called a 1/2-inch pipe because it
has a 1/2-inch inside diameter and pipes are usually sized according to their inside
diameter (ID). This dimension is also referred to as the nominal size, the size you
ask for at a plumbing supplier.
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If you are at all unsure about getting the right material, make things perfectly clear
by specifying ID for most pipes. In a minority of cases -- flexible copper lines, for
example -- pipe is ordered by using the outside diameter (OD).
If you can measure the inside dimension, you're home free. However, often you
won't have a way of measuring the inside of the pipe. Holding a ruler against a
pipe will give you only a rough idea of the outside diameter. Instead, use a string or
a set of calipers for a more exact measurement. Once you find the outside
dimension, use the chart on the last page to find the nominal size.
Fittings can be just as confusing. Their inside diameters must be large enough to
fit over the pipe's outside diameter so that a half-inch plastic elbow, for example,
has an outside diameter of about 1-1/4 inches.
As a rule of thumb, the OD of copper is 1/8 inch greater than its ID, the nominal
size. For plastic pipe, measure the OD and subtract 3/8 inch. For threaded and
cast-iron, subtract 1/4 inch.
Another mathematical pitfall for a beginning plumber is measuring the length of a
pipe running from one fitting to the next. Pipes must fully extend into fixture and
fitting sockets, or the joint could leak. Socket depths vary from one pipe size and
material to another, so you must account for the depth of each fitting's socket in
the total length of pipe needed between fittings.
The only times you don't have to take socket depth into account are when you are
using no-hub cast-iron pipes (see Tapping Into Cast-Iron Drain Lines, Related
Projects) or slip couplings with copper or plastic pipe (see Winterizing a House,
Related Projects).
o Inside measuring. If you have a pipe with an exposed end, simply measure
the pipe's inside diameter, and round off to the nearest 1/8 inch. Some
manufacturers indicate the size on the fittings.
o Outside measuring. You also can determine pipe size by measuring its
outside circumference. Wrap a string around the pipe, straighten it out, and
measure it. Use the chart below to find the nominal size you'll need to order.
o Add the socket depths. To figure the length of a pipe, first measure from
face to face, as shown above. Next, check the chart on the last page for the
socket depth of the material you're working with. Because pipes have
fittings on both ends, multiply by 2, and add the face-to-face length.
o Measuring copper or plastic in place. When working with copper or plastic -
- materials you can cut on the job -- often the most accurate way of
measuring is to insert the pipe into one fitting and mark the other end, rather
than using a tape measure.
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Title JOB SHEET # 4-1
Purpose Installing the identified life support system
Equipment, Tools & To enable the participants to gain knowledge and skills
Materials on installing a life support system
Precautions PVC/G.I. pipe, Regulating valve, Electrical tools, Hand
tools, Safety shoes, Gloves, Electrical materials
None
Procedures
STEP #1 Analyzing your piping system
The following procedure should be used to analyze your piping system or a piping system
you are considering:
1. Determine the required flow rate in gallons per minute (gpm). You may want to add
a safety factor, say 10 percent, to take care of pump wear and pipe aging.
2. Determine the lift in feet.
3. Choose the diameter of the pipe.
4. Determine the total equivalent length of the pipe. This is equal to the length of the
pipe plus the equivalent length of all fittings.
5. Use the velocity head table and diameter of the pipe at the discharge to determine
the velocity head. (It will not help much to suddenly enlarge the pipe here because
of the losses the enlargement will cause.)
6. Use the friction loss tables to determine the friction loss.
7. If the diameter of the pipe changes, treat each section of pipe of different
diameters separately and then add the total friction losses.
8. Add up the lift, the friction losses and the velocity head. The result is the total
head in feet that the pump will have to supply. The pressure (in psi) the pump must
supply is equal to the total head divided by 2.3.
9. The power a perfect pump (100 percent efficient) would require is called the water
horsepower and is computed as the sum of GPM multiplied by the Total Head (in
feet) divided by 3,960:
Water Horsepower = GPM x Total Head (in feet)
3,960
10. Examine the pressure and power requirements of the piping system. If the
performance is not suitable, try a different design and repeat the steps.
11. Determine the suction required of the pump. The suction required is the sum of the
lift to the pump, the friction head loss from the water source to the pump and the
velocity head. Choose a suitable pump. If no suitable pump can be found, redesign
the piping system.
STEP #2. How to evaluate an aerator.
Aerators are tested to determine the rate at which they transfer oxygen into water. These
tests are conducted in large tanks under standard conditions with clean tap water at 68° F
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and no initial dissolved oxygen. Two terms are commonly used to compare the aerator
performance:
o The standard oxygen transfer rate (SOTR) is the amount of oxygen that the
aerator adds to the water per hour under standard conditions and is
reported as lb O2/hr. Ratings for tractor-powered aerators are generally
given as standard oxygen transfer ratings (SOTR).
o The standard aeration efficiency (SAE) is the standard oxygen transfer rate
divided by the amount of power required and is expressed as lbs O2/hr per
horsepower (hp) or lbs O2/hp-hr. Smaller aerators are normally given
standard aeration efficiency ratings (SAE).
Efficiency ratings are based on the horsepower applied to the aerator shaft and not the
horsepower of the power source. Most commercial aerators have ratings between 1 and
5 lbs O2/hp-hr. Test results of different aerators can be compared in selecting an
effective and energy-efficient unit. Some manufacturers test their own equipment. When
comparing test results, it is important to know if test conditions were standardized. Also,
an aerator may have a high oxygen transfer rate with low efficiency rating. Cost of
operation should be less for a more efficient aerator.
STEP #3. Always stage your filtration.
Regardless of which type of filtering equipment you decide to use, the important thing to
keep in mind is to always stage your filtration. It is an all too common mistake to design a
system that relies too heavily on a single filtering device to provide all of the filtering
demands that a re-circulating system has. By staging your filtration, you will find your
system performing at or near its peak.
o Sedimentation - removal of solid wastes from the water:
6. Do whatever is possible to allow fish feces to drop intact into the
waste collection area or self cleaning bottom with minimal damage.
Minimize the use of pumps, aerators and air diffusers wherever feces
are present.
7. Do not pump the waste prior to separation. Design for gravity flow (or
siphon) into a sedimentation tank or basin. Splashing and turbulence
can attach air bubbles and break apart solids. Feces and food
particles smaller than 40 microns may not settle without chemical
flocculants.
8. Always locate your biofilter after the solids removal system. Solids
provide carbon for heterotrophic bacteria which can foul a biofilter
and/or reduce its performance.
9. Clean both the settling area and filters at least once a day even if
they contain little waste.
10. If further filtration is required after sedimentation, pump the water to
an affinity bead clarifier or particulate filter.
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o Mechanical entrapments or beads. Mechanical entrapments act like a net
or a filter cloth that allows the liquid to pass but not the solids. On the other
hand, bead filtration utilizes an electrostatic attraction to draw particles out
of the water.
Even as biofilter media can be incorporated at any point in the system,
many practitioners locate this biofiltration material as part of the mechanical
entrapment filters. Biofilters are merely "surfaces" which are "fed" water
containing ammonia. The "surfaces" include the inside surfaces of the water
pipes and fish tanks and the biofilter media, the beads in the bead filter, a
sand filter and a fluidized bed filter. After a period of time, the surface will
develop a slimy layer of nitrosomonas and nitrobacter bacteria. The
population of these bacteria will continue to multiply until their population
becomes proportional to their food supply: ammonia and nitrite.
o Degassing - removal of dangerous gasses from the water:
Degassing is a process which is used to remove undesirable gasses, that
are present in greater concentrations in the water than would otherwise
naturally be found. When they are in this state, such gasses are called
supersaturated gasses. When exposed to an interface between air and
water, supersaturated gas has a natural tendency to escape out of the
water and into the surrounding air. The main function of a degasser is to
create a large interface between the water and the air. This is achieved in a
variety of ways. One way is by heavy aeration, where the surface area of
the bubbles creates a large interface as they rise through the water.
Aeration also creates a lot of turbulence, bringing water to the surface
where the gas can escape directly to the atmosphere. Another degassing
method is letting the water fall over weirs and cascades, where it is broken
up into droplets, thereby increasing the interface. Also commonly used are
packed columns, which are vessels filled with a type of media over which
the water runs.
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SELF CHECK #4-1
1. Discuss the process determining the appropriate aerator system for the hatchery.
2. Do you know the difference between filtration and bio-filtration systems?
3. Describe how to determine the appropriate pump and pump capacity.
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ANSWER KEY #4-1
1. Discuss the process determining the appropriate aerator system for the
hatchery.
Answer:
• How to evaluate an aerator. Aerators are tested to determine the rate at which
they transfer oxygen into water. These tests are conducted in large tanks under
standard conditions with clean tap water at 68° F and no initial dissolved oxygen.
Two terms are commonly used to compare the aerator performance:
o The standard oxygen transfer rate (SOTR) is the amount of oxygen that the
aerator adds to the water per hour under standard conditions and is
reported as lb O2/hr. Ratings for tractor-powered aerators are generally
given as standard oxygen transfer ratings (SOTR).
o The standard aeration efficiency (SAE) is the standard oxygen transfer rate
divided by the amount of power required and is expressed as lbs O2/hr per
horsepower (hp) or lbs O2/hp-hr. Smaller aerators are normally given
standard aeration efficiency ratings (SAE).
Efficiency ratings are based on the horsepower applied to the aerator shaft and not
the horsepower of the power source. Most commercial aerators have ratings
between 1 and 5 lbs O2/hp-hr.
2. Do you know the difference between filtration and bio-filtration systems?
Answer:
• Filtration. Filtration is the removal of solid and suspended wastes. The methods
of filtration ranges from sedimentation tanks, screen mesh to sieve particles, to the
use of materials that “statically” attracts suspended particles.
• Biofiltration. Biofiltration is the aerobic (with oxygen) breakdown of dissolved
nitrogenous fish waste (ammonia). Fish will excrete about 14 grams of ammonia
for each pound of food eaten (at 35% protein). The nitrification of ammonia is
accomplished by two strains of autotrophic bacteria. These bacteria are naturally
occurring and will ultimately colonize the bio-media in your biofilter as well as the
tank walls etc. The speed of this process is dependent on temperature, pH,
salinity surface area, flow rate, etc.
3. Describe how to determine the appropriate pump and pump capacity.
Answer:
• Basic Considerations in Selecting Pumps.
o Pump efficiency. Selecting a correct pumping plant not only will conserve
valuable energy supplies but also will reduce total annual pumping costs.
o Well size and capacity limits. There are definite capacity limitations for a
given diameter of well casing. To obtain this limit, the pump must have
sufficient capacity. Maximum permissible speed depends upon a number of
factors, but for 4-inch, 6-inch and even 8-inch pumps, a speed of 3,600 rpm
Code No. Designing, Lay-outing and Constructing of a Date: Date Page #
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is not uncommon.
o Pumping from a well. If you observe a surge in the discharge, the pump
may be having difficulty getting enough water. Assuming that adequate
water is available to flow into the well and that encrusted wells are not the
problem, then the surge is normally caused by the pump not being
submerged enough to provide water for intake. Where the pump is located
some distance from the bottom of the well, it is often possible to lower the
pump and reduce the amount of surging. This can require more power
since full water flow may be obtained along with higher head.
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Performance Assessment
EVIDENCE PLAN
Sector: AGRI-FISHERY
Unit of Competency: Operate Marine Finfish Hatchery
Module Title: Designing, Lay-outing and Construction of Marine Finfish Hatchery
Ways in which evidences will be collected: Interview
Demonstration
(tick the column) with Questioning
Observation with
The evidence must show that the candidate … Questioning
Written Test
Presentation of
Final Product
Third Party Report
Portfolio
1. Will be able to select suitable sites, complying with X X
national laws/rules X X
X
2. Identify and determine basic components and design X
parameters of marine finfish hatchery. X X
X X
3. Prepare a site plan. X
4. Prepare the layout design of the hatchery.
5. Prepare the Bill of Materials and Summary Cost
Estimates.
6. Make a canvass of the pumps that are available in
your locality and list down their respective features.
7. Make a checklist of the documents needed to be
gathered and analyzed during the pre-construction
activities.
8. Select the best protective equipment from your list of
available equipment in the market by using
procedure on ensuring safety at the workplace.
9. Prepare and fill up index cards for recording the
features of each piping system to be used in the
hatchery.
10. Make a checklist of the different features and
essential points of different aerators.
11. Make a list of your options and select your best
choice for powering life support systems for a marine
finfish hatchery.
Note: *Critical aspects of competency
Prepared by: Date:
Instructor
Date:
Supervisor
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PERFORMANCE TEST
Learner’s Name: Date:
Competency: Operate Marine Finfish Hatchery
Test Attempt
1st 2nd 3rd
Directions: OVERALL EVALUATION
Level
CALL INSTRUCTOR. Ask Achieved PERFORMANCE LEVELS
instructor to assess your 4 – Can perform this skill without supervision
performance in the following and with initiative and adaptability to
critical task and performance problem situations.
criteria below. 3 – Can perform this skill satisfactorily without
You will be rate based on the assistance or supervision.
overall evaluation on the
right side. 2 – Can perform this skill satisfactorily but
requires some assistance and/or
supervision.
1 – Can perform parts of this skill satisfactorily,
but requires considerable assistance and/or
supervision.
Instructor will initial the level achieved.
PERFORMANCE STANDARDS Yes No N/A
For acceptable achievement, all items should receive a “Yes”
or “N/A” response.
1. Did you identify the basic components and design of a marine finfish
hatchery?
2. Have you laid out or drawn different parts of marine finfish hatchery?
3. Have you properly identified and prepared different materials to be used in
marine finfish hatchery?
4. Have you selected and prepared equipment required in marine finfish
hatchery construction?
5. Have you selected and prepared required materials for marine finfish hatchery
construction?
6. Did you properly identify and construct marine finfish hatchery facilities
according to plan?
7. Did you follow the procedure for identifying and preparing life support
systems?
8. Have you identified and prepared different parts of life support systems?
9. Did you properly follow the procedure for installing life support systems?
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Assessment Instruments
DEMONSTRATION WITH QUESTIONING
Candidate’s name Operate Marine Finfish Hatchery
Assessor’s name Aquaculture NCIII
Competency Assessment Title
Qualification
Date of Assessment
Time of Assessment
Instructions for Demonstration
Given the following materials tools and equipment, the candidate must be able to
Operate a Marine Finfish Hatchery
a. Writing pad d. Aerator g. Plumbing tools j. Mats
b. Writing instruments e. Incubator h. Hoses k. Baskets
c. Calculator f. Electrical tools I. Air stones
OBSERVATION Tick (/) to show if evidence is
Demonstrated.
During the demonstration of skills, did the Yes No Actual
5.0
candidate: 1.0-3.0
1. Layout and draw the basic design of a
marine finfish hatchery.
2. Select and prepare equipment to be
used
3. Select and prepare required materials in
setting up a marine finfish hatchery
4. Construct hatchery facilities according to
plan
5. Prepare the different parts of life support
systems.
6. Observe procedure for ensuring safety in
the workplace.
7. Install life support systems.
The candidate’s demonstration was :
Rating ________
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DEMONSTRATION (continued)
Questions Satisfactory Response
The candidate should answer the following Yes No
questions:
1. What are the critical considerations in site
selection?
2. List down the basic consideration in designing a
hatchery
3. What is the role of management in the
construction proper?
4. Do you know the difference between filtration
and bio-filtration systems?.
5. What are the basic considerations in selecting a
pump?.
The candidate’s underpinning knowledge was:
Rating_______
Feedback to candidate
The candidate’s overall performance was: Date:
Rating:__________ Date:
Candidate’s signature
Assessor’s signature:
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Record of Achievement
Module 1 Designing, Lay-outing and Construction of a Marine Finfish Hatchery
Learning Outcome # 1: Draw and set up a complete facility for a marine finfish
hatchery
Performance Criteria
1. Marine fish hatchery facilities are identified
2. Size, shape and design are determined
3. Marine fish hatchery lay-out is drawn
Comments
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Learner has satisfied the above performance criteria.
Learner’s signature …………………………………….
Trainer’s signature………………………………………
Date ……………………………………………………...
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Record of Achievement
Module 1 Designing, Lay-outing and Construction of a Marine Finfish Hatchery
Learning Outcome # 2: Identify tank / pond materials to be used
Performance Criteria
1. Components of hatchery are identified and described
2. Appropriate materials are listed
Comments
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Learner has satisfied the above performance criteria.
Learner’s signature …………………………………….
Trainer’s signature………………………………………
Date ……………………………………………………...
Code No. Designing, Lay-outing and Constructing of a Date: Date Page #
Marine Finfish Hatchery Developed Revised: 149
10/24/ 2004 10/20/ 2005
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