Activated Sludge Production Parameters and Nutrient Content of Organic Sludge Components

Abstract

An important part of biological treatment system design is quantifying the sludge production and the nutrient removal capacity. Influent wastewater COD fractionation, biomass growth and endogenous respiration directly impacts the composition of the mixed liquor solids in activated sludge systems. The objectives of this project were to determine the model kinetic and stoichiometric parameters associated with activated sludge production and the nutrient content (N and P) of unbiodegradable organic matter components. A complete sludge retention experiment was conducted over 70 days in a pilot-scale membrane bioreactor fed with a real municipal wastewater, and operated with alternating growth and famine periods. Experimental results were simulated and compared using the default values from two well-accepted model parameter sets. The General ASDM parameter set was found to better fit the experimental data than the Metcalf and Eddy parameter set, mainly to characterize endogenous respiration and the heterotrophic biomass concentration. An influent unbiodegradable organic particulate fraction (fXU,Inf) value of 0.16 g COD/g COD was determined by calibration of the accumulated sludge total COD, suspended solids and heterotrophic biomass concentrations. The nutrient content of the accumulated endogenous residue (XE) and influent unbiodegradable organic particulate (XU,Inf) components were calibrated to 0.030 and 0.100 g N/g COD and 0.035 and 0.008 g P/g COD, respectively. These values are in the range of those reported in the literature except for the high P content found in the endogenous residue, possibly due to the presence of coagulants added for P removal in the accumulated sludge. These results were consistent under the wide range of dynamic conditions tested and could improve model prediction of sludge production and composition.

Characterization of Wastewater Quality and Denitrification Potential of Domestic Wastewater

“…A difference in OUR (ΔOUR) for the injected substrate concentration was calculated by subtracting the background OUR from the total OUR. The biomass content in COD (1.48 mg COD/mg VSS ×VSS) (Labelle et al, 2017;Torretta et al, 2014) was used to derive the specific ΔOUR (rresp, OX). Equation ( 8) was used to get the growth rate.…”

Modeling, Instrumentation, Automation, and Optimization of Water Resource Recovery Facilities

“…The membrane aerated biofilm reactor (MABR) was modelled using GPS-X during a 500 days pilot scale operation (Peeters et al, 2017). The General Activated Sludge and Digestion Model (ASDM) parameter set was better than the Metcalf and Eddy parameter set in fitting the experimental data generated from sludge retention over 70 days in a membrane bioreactor operated with alternating growth and famine periods (Labelle et al, 2017).…”