_O & M MANUAL - WEST LANE MOBILE HOME PARK

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To Convert to lbs/day: (influent flow mgd) x (weight of water lbs/gallon) x (MLSS mg/1) =lbs/day of MLSS Given a BOD of 120 mg/ Given Influent flow of 54,000 gpd or .0540 mgd (.0540 rngd) x (8.34 lbs/gal) x (3,600 mg/1) = 1,621 lbs/day of MLSS Quantity of Microorganisms—Mixed Liquor Volatile Suspended Solids Mixed Liquor Volatile Suspended Solids (MLVSS) is composed mostly of microorganisms and some organic material. Thus, it is approximately equal to the amount of microorganisms in the wastewater and can be used to see if there are enough microorganisms available for the food in the system. MLVSS is determined by igniting a sample of dried MLSS in a furnace. The portion that burns is considered to be the microorganisms and therefore the remaining amount is inorganic material. The portion that burns is the MLVSS and is what eats the incoming food.At Wildwings,the MLVSS is done at an outside lab. MLVSS is typically 70%to 80% of the MLSS. if the MLVSS number is not available,then use the MLSS to get an estimate of the bacteria available. The quantity of microorganisms that are available for treatment are calculated by multiplying the volume of the aeration tank in millions of gallons by the weight of a gallon of water (8.34 lbs/gal) times the MLVSS in mg/I.The volume of the aeration tank is 0.128 mg at the Wildwings facility. Quantity of Bacteria Formula— MLVSS lbs (aeration tank volume Mg) x (weight of water lbs/gal) x (MLVSS mg/1) = Pounds of MLVSS Example: Given aeration tank volurne of 0.128 million gallons Given MLVSS of 2520 mg/I ❖ (0.128 rng) x (8.34 lbs/gal) x (2520 mg/1) = 2690 pounds of microorganisms (MLVSS) Sludge Volume Index-SVI Sludge Volume Index (SVI) describes how well the sludge from the aeration tank settles and compacts. Trending the SVI can help indicate changes happening, and prevent settling problems before they occur. To Increase SVI, increase the wasting rate and to decrease SVI, reduce the wasting rate. • An SVI of 80 or less usually indicates a sludge that is dense and has rapid settling characteristics. • SVI of 100 to 200 usually produces a high-quality effluent. The 5ludge typically 5ettles slower and traps more particulate matters and forms a uniform blanket before settling.