Solids retention time

BSRT Biomass solids retention time NSPS New source performance standards... 

Clara M, Kreuzinger N, Strenn B, Gans O, Kroiss H (2005) The solids retention time a suitable design parameter to evaluate the capacity of wastewater treatment plants to remove micropollutants. Water Res 39 97-106... 

WWTP7). On the other hand, solids retention times are between 3 and 4 days (WWTP5, WWTP6) and 19 days (WWTP7). 

The removal rate of pharmaceuticals by WWTPs depends on factors such as reactor configuration, redox conditions, temperature, hydraulic retention time (HRT) and solid retention time (SRT). SRT is the average retention time of sludge... 

Solids retention time (SRT), 25 900 Solids separation, in solid-liquid separation, 11 342, 344 Solids suspension(s), 7 272t, 16 692-696 degrees of, 16 693 occurrences of, 7 273t Solid-state hydrogen, 13 850 Solid-state crossed Cannizzaro reactionp, 16 574... 

There is an apparent upper limit to the strength of waste a biological system ean handle in a liquid system. In some cases the constraint is oxygen transfer. In other eases it is the solids concentration in the mixed liquor and the shear whieh is neeessary to keep it in suspension. Recent work with membranes replaeing the elarifiers have indicated that the upper limit to solids is between 2% and 4% total solids, but not all of that is active biomass. The solids retention time in the system is often well over 40 days. The apparent upper limit on waste expressed as BOD is about 600mg/l -800 mg/1. Stronger wastes ean be treated, but they comprise a portion of the total flow and in effect are diluted. 

Melcer and Bedford (1988) studied the fate of pentachlorophenol in municipal activated sludge reactor systems that were operated at solids retention times of 10 to 20 d and hydraulic retention times of 120 d. Under these conditions, pentachlorophenol concentrations decreased from 0.1 and 12 mg/L to <10 pg/L. At solids retention times of 5 d or less, pentachlorophenol degradation was incomplete. 

Estimate the food-microorganism ratio (F/M) and sludge age (solid retention time) of an activated sludge process designed to reduce the BOD5 of the spent stream generated from a biological production plant from 1500 mg/L to 50 mg/L. The wastewater flow is Q = 15,000 GPD, aeration tank volume = 45 m, MLVSS = 3000 mg/L, and net biomass yield coefficient (Tn) = 0.28 kg/kg. Also compute the performance efficiency of the plant. 

A) Determine the size of the aerated lagoon based on 9 (solid retention time) ... 

Determine the F/M ratio and solid retention time of an extended aeration system designed for the treatment of 33,800 GPD of pharmaceutical wastewater. The BOD5 of the raw wastewater and treated effluent are 5000 mg/L and 560 mg/L, respectively. Assume the following data and conditions are applicable ... 

Involves a sample being vaporized and injected into the head space of the chromatographic column. The sample is transported through the column by the flow of an inert gas (mobile phase). The column itself contains a liquid stationary phase which is adsorbed onto the surface of an inert solid. Retention time with detection techniques (spectrophotometer, mass spectrometry, fluorescence) identifies the compound. 

Kim, S., P. Eichhom, J.N. Jensen, et al. 2005. Removal of antibiotics in wastewater Effect of hydraulic and solid retention times on the fate of tetracycline in the activated sludge process. Environ. Sci. Technol. 39 5816-5823. 

In addition to the usual reactor design parameters, height of the fluidized bed is controlled by the gas contact time, solids retention time, bubble size, particle size, and bubble velocity. 

Fixed-biofilm processes offer the advantage of high concentrations of biomass in relatively small reactors, as little biomass is lost in the effluent. The result is a long solids retention time (necessary to foster slow-growing microorganisms) and the possibility of degrading hazardous contaminants or wastes with low concentrations of organics. 

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