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23 Cards in this Set
- Front
- Back
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Difference between a stabilization pond and a facultative lagoon |
A stabilization pond is designed to be aerobic throughout its depth and a facultative lagoon will be anaerobic at the bottom and aerobic at the top. |
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What must come before a stabilization pond? |
A Primary clarifier or Imhoff Tank |
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Three requirements of most states for pond operation |
Multiple ponds in series, detention times of 30 days or more, and a clay or artificial liner |
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One surface acre will provide treatment for approximately ______ people |
300-400 |
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Amount of freeboard required for periods of heavy rainfall |
2-3' |
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Slope of the embankment |
1 to 3 feet vertical to horizontal |
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Typical length to width ratio |
3 to 1 |
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Protection of the banks against erosion |
Special type of glass or rip rap |
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Way of preventing short circuiting |
Multiple submerged inlets and outlets |
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Typical pond loading rate |
30-50 lbs BOD per acre per day |
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Average depth of a stabilization pond |
3-5 feet |
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Average depth of a facultative lagoon |
5-8 feet |
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Why are facultative lagoons deeper than stabilization ponds? |
They do not require primary treatment and added depth is needed to handle the increase solids loadings. |
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Describe the activity at the bottom of a facultative pond |
It provides a storage area where anaerobic and facultative bacteria slowly stabilize the organic material. |
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Parameters of a typical pond permit (discharge and monitoring) |
30 BOD, 90 TSS. Monitor BOD, TSS, flow, DO, and pH |
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Typical setup and order of ponds |
First a facultative pond with a depth of around 10 feet, then stabilization ponds |
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Describe the O2/CO2 cycle in a pond |
Pond systems stabilize organic material through natural processes involving sunlight, water, nutrients, algae, atmospheric oxygen and bacterial action. Organic matter in the wastewater is broken down by aerobic bacteria and oxygen found in the pond. This process releases carbon dioxide which is used by the algae to produce simple sugars through a process known as photosynthesis. Oxygen is the by-product of this reaction which is used by other aerobic bacteria to stabilize more organic matter. This becomes a continuous cycle. |
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List four organisms involved in a pond treatment process |
Bacteria Algae Protozoa Insects |
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What two other things do ponds do a great job of reducing? |
Fecal coliform and ammonia |
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What organism tends to dominate the pond environment in the summer and under what conditions? |
Blue green algae dominates under high organic loadings because the nitrogen in wastewater stimulates the growth. |
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Sign of a large blue-green algae bloom |
An obnoxious pig-pen odor. Bad smell but good at reducing ammonia concentrations. |
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% BOD reduction typical of a well operated pond |
80-90% |
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Downside of a pond system |
The amount of land required |
