Heterotroph anoxic yield in anoxic aerobic activated sludge systems treating municipal wastewater

2003 ◽  
Vol 37 (10) ◽  
pp. 2435-2441 ◽  
Author(s):  
A. Muller ◽  
M.C. Wentzel ◽  
R.E. Loewenthal ◽  
G.A. Ekama
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Activated Sludge Systems

Virus elimination in activated sludge systems: from batch tests to mathematical modeling

2014 ◽  
Vol 70 (6) ◽  
pp. 1115-1121 ◽  
Author(s):  
Emma Haun ◽  
Katharina Ulbricht ◽  
Regina Nogueira ◽  
Karl-Heinz Rosenwinkel
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Virus Concentration ◽  
Extended Model ◽  
Municipal Wastewater Treatment ◽  
Virus Elimination ◽  
Somatic Coliphages ◽  
Batch Tests ◽  
Activated Sludge Systems

A virus tool based on Activated Sludge Model No. 3 for modeling virus elimination in activated sludge systems was developed and calibrated with the results from laboratory-scale batch tests and from measurements in a municipal wastewater treatment plant (WWTP). The somatic coliphages were used as an indicator for human pathogenic enteric viruses. The extended model was used to simulate the virus concentration in batch tests and in a municipal full-scale WWTP under steady-state and dynamic conditions. The experimental and modeling results suggest that both adsorption and inactivation processes, modeled as reversible first-order reactions, contribute to virus elimination in activated sludge systems. The model should be a useful tool to estimate the number of viruses entering water bodies from the discharge of treated effluents.

scholarly journals Coke oven wastewater treatment by two activated sludge systems

2013 ◽  
Vol 8 (1) ◽  
pp. 16-22
Keyword(s):  
Organic Matter ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Coke Oven ◽  
Synthetic Wastewater ◽  
Removal Efficiencies ◽  
Activated Sludge Systems

In this study two bench scale activated sludge systems were used, a CSTR and an SBR for the treatment of coke – oven wastewater. Both reactors were inoculated with activated sludge from a municipal wastewater treatment plant. At the first stages of operation, reactors were feed by a mixture of municipal wastewater and synthetic wastewater. Full acclimatization of the microorganisms to synthetic wastewater was achieved in 60 days. The operation of the reactors was divided into three distinct periods. The first period was characterized by the treatment of high organic but non-toxic synthetic wastewater. During this period COD and BOD5 removal efficiencies reached 95 and 98% respectively, in both reactors. Nutrient removal was better in the SBR reactor rather than in the CSTR. In the second period phenol was added in concentrations up to 300 mg l-1. Degradation of phenol started about the 20th day after its introduction to the reactors. In this period no effects of phenol to nutrient removal were observed, whereas the removal efficiency of organic matter in both reactors was slightly decreased. During the third period phenol concentrations of the influent were gradually increased to 1000 mg l-1, while cyanide and thiocyanite were added to the influent composition to concentrations reaching concentrations of 20 and 250 mg l-1 respectively. The composition of the influent of this period was a full assimilation of coke oven wastewater. Introduction of increased phenol concentrations along with cyanide compounds initiated irreversible effects on the activated sludge microfauna of the CSTR causing inherent problems to the treatment process, while SBR showed greater capacity to withstand and degrade toxic compounds. The beginning of this period was characterized by decreased settleability of the suspended solids as well as decrease of organic matter and nutrient removal efficiencies. Monitoring of the effluent characteristics during this period reported over 90% for organic load, 85% of nutrient removal and over 90% of phenol and cyanide removal in SBR, while the removal efficiencies for the CSTR were 75, 65 and 80% respectively.

Nitrification Kinetics in Single-Sludge Biological Nutrient Removal Activated Sludge Systems

1992 ◽  
Vol 25 (6) ◽  
pp. 195-214 ◽  
Author(s):  
C. W. Randall ◽  
V. M. Pattarkine ◽  
S. A. McClintock
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Municipal Wastewater ◽  
Biomass Concentration ◽  
Biological Nutrient Removal ◽  
Mixed Liquor ◽  
Nitrification Kinetics ◽  
Anoxic Zones ◽  
Complete Nitrification ◽  
Activated Sludge Systems

Nitrification kinetics as a function of mixed liquor temperature were compared for a conventional fully-aerobic activated sludge system and a system accomplishing biological nutrient removal (BNR) by incorporation of anaerobic and anoxic zones using the UCT configuration. The systems treated the same municipal wastewater and both had flow rates of 151 L/day. The nitrification rates were greater in the nutrient removal system compared to the conventional system as long as the aerobic MCRT was above the minimum for complete nitrification. It was concluded that BNR systems require less aerobic volume than fully aerobic systems to accomplish nitrification because the aerobic biomass concentration is greater in the BNR systems, particularly if the UCT configuration is used. Nonetheless, BNR systems require more total volume to accomplish complete nitrification than fully aerobic systems, and the volume differential increases as mixed liquor temperatures decrease.

Fate of Trichloroethylene in Activated Sludge Systems

1987 ◽  
Vol 22 (3) ◽  
pp. 403-411
Author(s):  
W. Bedford ◽  
H. Melcer
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Equilibrium Concentration ◽  
Sampling Technique ◽  
Time Interval ◽  
Mass Balances ◽  
Mixed Liquor ◽  
Liquid Phases ◽  
Gas Tight ◽  
Activated Sludge Systems

Abstract This study was undertaken to investigate the fate of a volatile organic priority pollutant, trichloroethylene (TCE), in activated sludge systems treating municipal wastewater. Batch stripping tests were carried out in a 2 L glass vessel to develop sampling techniques for vapour and liquid phases and to refine analytical protocols. The vapour sampling technique found to be most reliable involved collection of all exhaust vapours in a 40 L Tedlar bag. Equipment which was impervious to the volatile characteristics of TCE was imperative. Continuous flow experiments were carried out in a 15 L gas-tight bench-scale activated sludge system. Experiments were conducted for influent TCE concentrations ranging from 20 to 150 Mg/L and at aeration rates of 0.13 and 0.26 volume of air/volume of mixed liquor-minute. Mass balances for TCE were carried out when the TCE adsorbed by the biomass had reached an equilibrium concentration. A minimum of four hydraulic retention times (HRTs) were required before constant biomass TCE concentrations were observed. Subsequently, grab samples of influent, effluent and mixed liquor were taken within a discrete time interval during which a volume of exhaust gas was collected in a Tedlar bag. The mass balances were based upon TCE analysis of these samples. The first experiments were carried out without mixed liquor to eliminate possible loss of TCE by biodegradation. Approximately 10% of the influent TCE could not be accounted for in these experiments. This loss was attributed to sampling and analytical errors. With mixed liquor present, 60 to 70 % mass balance closures were achieved. Approximately 20 to 30 % of the TCE losses were attributed to biodegradation.

Modelling carbon oxidation in pulp mill activated sludge systems: calibration of Activated Sludge Model No 3

2004 ◽  
Vol 50 (3) ◽  
pp. 1-10 ◽  
Author(s):  
P.A. Barañao ◽  
E.R. Hall
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Pulp Mill ◽  
Paper Mill ◽  
Pulp And Paper Mill ◽  
Activated Sludge Model ◽  
Batch Tests ◽  
Different Temperatures ◽  
Activated Sludge Systems

Activated Sludge Model No 3 (ASM3) was chosen to model an activated sludge system treating effluents from a mechanical pulp and paper mill. The high COD concentration and the high content of readily biodegradable substrates of the wastewater make this model appropriate for this system. ASM3 was calibrated based on batch respirometric tests using fresh wastewater and sludge from the treatment plant, and on analytical measurements of COD, TSS and VSS. The model, developed for municipal wastewater, was found suitable for fitting a variety of respirometric batch tests, performed at different temperatures and food to microorganism ratios (F/M). Therefore, a set of calibrated parameters, as well as the wastewater COD fractions, was estimated for this industrial wastewater. The majority of the calibrated parameters were in the range of those found in the literature.

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