ONSITE TREATMENT Flashcards
It is buried, watertight receptacles designed and constructed to receive wastewater from the structure to be served.
Septic Tanks
It separates solids from the liquid, provides limited digestion of organic matter, stores solids, allows the clarified liquid to discharge.
Septic Tanks
What are the three products of septic tanks?
Scum
Sludge
Effluent
It is called the “sinkable” solids (soil, grit, bones, unconsumed particles) settle to the bottom of the tank. Anaerobic bacteria works.
Sludge
It is called the substances lighter than water (oil, grease, fats) float to the top.
Scum
It is called the clarified wastewater left over after the scum has floated to the top and the sludge has settled to the bottom.
Effluent
It flows through the septic tank outlet into the drain field.
Effluent
It is one of the parameters of septic tanks that refers to the liquid volume in the clear space between the scum and sludge layers.
Effective Volume
It is one of the parameters of septic tanks that refers to the time the water spends in the tank, on its way from inlet to outlet.
Retention Time
It is one of the parameters of septic tanks that refers to the function of the effective volume and the daily household wastewater flowrate.
Retention Time
What is the formula of retention time?
Retention Time (days) = Effective Volume (gal)/Flow Rate (gal/day)
A common design rule is for a tank to provide a minimum retention time of at least ____ hours, during which one-half to two-thirds of the tank volume is taken up by sludge and scum.
24
Under ordinary conditions (i.e., with routine maintenance pumping) a tank should be able to provide ___________ of retention time.
2 to 3 days
It refers to an artificially created water bodies.
Constructed Wetlands
It is typically a long, narrow trenches or channels to promote the occurrence of plug flow conditions.
Constructed Wetlands
It is typically a 1-m deep basin which is sealed with clay or some other form of lining to prevent percolation into groundwater.
Constructed Wetlands
It is filled with soil in which reeds are then planted.
Constructed Wetlands
It can significantly remove BOD, TSS, nitrogen and phosphorus, as well as metals, trace organics and pathogens.
Constructed Wetlands
What are the two main operational conditions of constructed wetlands?
Mosquito Control and Plant Harvesting
It is a primary settling basin or an anaerobic reactor commonly precedes constructed wetlands for sewage treatment.
Septic Tank
What are the two systems of constructed wetlands?
- Free water surface systems with shallow water depths.
- Subsurface flow systems with water flowing laterally through the sand or gravel.
How many galloons per acre per day is considered for the maximum hydraulic design loading flow through rate on the artificial wetlands?
25000 galloons per acre per day.
What is the range (in days) for the minimum recommended detention time for treatment in the artificial wetland system?
7-14 days (Note: Most desirable ang 14 days)
What is the recommended depth of flow in the wetland system? What about the recommended optimum depth?
6-24 inches
9 inches
What configuration for constructed wetlands is recommended to enhance treatment efficiency in the system with a length to width ratio of between 5 and 10 to 1.
Rectangular configuration
________________ should be considered to prevent aging of the wetland. Harvesting or burning are two options available.
Detritus removal
To provide the greatest potential for wildlife enhancement, about how many percent of the artificial wetland surface should be open water with a depth no greater than five feet?
25 to 35 percent
The emergent vegetation should comprise about how many percent of the available surface area with a water depth of less than two feet deep?
65 to 75 percent
It is with the addition of algal population.
Lagoons
It is where oxygen is supplied by natural reaeration from the atmosphere and algal photosynthesis.
Lagoons
It is where the degradation by bacteria releases carbon dioxide and nutrients used by algae.
Lagoons
It is where higher life forms such as rotifers and protozoa primarily as polishers of the effluent.
Lagoons
It is where the temperature has a significant effect on aerobic pond operation.
Lagoons
What are the five major factors of lagoons?
Organic loading, pH, nutrients, sunlight, and degree of mixing
The total organic loading for the total surface area shall not exceed to how many pounds of BOD5 per acre per day?
20 pounds
For lagoons, the design average flow rate shall be used to determine the volume required to provide a minimum liquid retention of how many days?
180 days
The minimum depth for lagoons must be ___ feet. The maximum normal liquid depth should not exceed ___ feet.
2,6
Oxygen requirements generally will depend on the ___________, the ___________________ and the ______________________________ to be maintained.
BOD loading, degree of treatment, concentration of suspended solids
Aeration equipment shall be capable of maintaining a minimum dissolved oxygen level of ___ mg/l in the ponds at all times.
2
