scholarly journals Nutrient recovery as struvite from conventional activated sludge treatment plants

2019 ◽  
Author(s):  
Chathurani Moragaspitiya
Keyword(s):  
Activated Sludge ◽  
Nutrient Recovery ◽  
Sludge Treatment ◽  
Conventional Activated Sludge

scholarly journals Estimating the impact of inhibitory substances on activated sludge denitrification process

2019 ◽  
Vol 14 (4) ◽  
pp. 863-871 ◽  
Author(s):  
Kati Klein ◽  
Taavo Tenno
Keyword(s):  
Standard Deviation ◽  
Oxygen Uptake ◽  
Activated Sludge ◽  
Process Efficiency ◽  
Sludge Treatment ◽  
Conventional Activated Sludge ◽  
Uptake Rates ◽  
Relative Standard ◽  
The Impact ◽  
Denitrification Process

Abstract Industrial wastewater frequently contains substances which inhibit activated sludge treatment processes. Inhibitory characteristics of different substances are usually evaluated based on testing the impact of respective substance on activated sludge nitrification or oxygen uptake rates. However, denitrification is always before aerobic processes in conventional activated sludge treatment plants and thereby more exposed to inhibitory compounds. There is no easily applicable and validated method available for determination of denitrification process efficiency and inhibition. In this study, a method for evaluation of inhibition on the activated sludge denitrification process was developed and validated using 3,5-dichlorophenol (3,5-DCP) as a model inhibitory compound and additionally controlled with real wastewater produced in the shale oil industry. Average IC50 value (5.5 ± 2.2 mg L−1) for 3,5-DCP showed that denitrifiers were less sensitive than nitrifiers (IC50 = 2.9 ± 0.7 mg L−1) and more sensitive than aerobic heterotrophs (IC50 = 7.2 ± 2.4 mg L−1). Methodological aspects like accumulation of nitrite nitrogen, acclimatization of biomass and technical issues were discussed. Achieved validation characteristics were similar with ISO Standards estimating activated sludge nitrification and oxygen uptake rates, which proves the reliability of the method: standard deviation, 95.4% confidence level, relative standard deviation were calculated to be 2.2 mg L−1, 1.2 … 9.8 mg L−1 and 39.2%, respectively.

Occurrence of benzothiazoles in municipal wastewater and their fate in biological treatment

2004 ◽  
Vol 50 (5) ◽  
pp. 203-208 ◽  
Author(s):  
A. Kloepfer ◽  
R. Gnirss ◽  
M. Jekel ◽  
T. Reemtsma
Keyword(s):  
Activated Sludge ◽  
Sulfonic Acid ◽  
Biological Treatment ◽  
Municipal Wastewater ◽  
Total Concentration ◽  
Sewage Treatment ◽  
Liquid Chromatography Mass Spectrometry ◽  
Sludge Treatment ◽  
Conventional Activated Sludge ◽  
The Individual

A number of 2-substituted benzothiazoles that are known to be used as fungicides, corrosion inhibitors and vulcanization accelerators in industry have been analyzed in municipal wastewater and the effluents of activated sludge and membrane bioreactor (MBR) treatment over a three month period. All six analytes were regularly detected in the municipal wastewater by liquid chromatography-mass spectrometry and amount to a total concentration of 3.4 μg/L. Of these compounds benzothiazole-2-sulfonic acid (1,700 ng/L), benzothiazole (850 ng/L) and 2-hydroxybenzothiazole (500 ng/L) were most prominent. The source of the benzothiazole emission is yet unknown. Activated sludge treatment did not reduce total benzothiazole concentration significantly. Removals of the individual compounds ranged from 90% for 2-mercaptobenzothiazole and 70% for hydroxybenzothiazole to 40% for benzothiazole. The concentration of benzothiazole-2-sulfonic acid increased by 20%, whereas 2-methylthiobenzothiazole increased by 160% during activated sludge treatment, likely due to the methylation of mercaptobenzothiazole. Total benzothiazole removal in two parallely operated MBRs was significantly better (43%) than in the conventional activated sludge treatment. Namely benzothiazole and benzothiazole-2-sulfonic acid were more effectively removed. This first systematic study on the occurrence of benzothiazoles in municipal wastewater has shown that this is a relevant class of trace contaminants in municipal wastewater which is only incompletely removed in biological wastewater treatment. Emission from sewage treatment is dominated by the most polar benzothiazole-2-sulfonic acid. MBR treatment may reduce but cannot avoid this emission.

scholarly journals Clustering micropollutants based on initial biotransformations for improved prediction of micropollutant removal during conventional activated sludge treatment

2020 ◽  
Vol 6 (3) ◽  
pp. 554-565 ◽  
Author(s):  
Yuxin Wang ◽  
Kathrin Fenner ◽  
Damian E. Helbling
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Sludge Treatment ◽  
Conventional Activated Sludge ◽  
Micropollutant Removal

The lack of fundamental insights on the fate of micropollutants during activated sludge treatment presents one of the biggest challenges in optimizing their removal in wastewater treatment plants.

Design of Anaerobic Digestion of Lime Sludges

1984 ◽  
Vol 16 (12) ◽  
pp. 375-386
Author(s):  
B A Bell ◽  
E A Kobylinski
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Energy Requirements ◽  
Treatment Facility ◽  
Sludge Treatment ◽  
Phosphorous Removal ◽  
Conventional Activated Sludge ◽  
Volatile Solids ◽  
Lime Addition

Previous work has demonstrated that inhibition of volatile solids destruction during anaerobic digestion occurs at elevated calcium levels. In this work, calcium inhibition has been taken into account in the design of a treatment facility digesting sludges which contain lime from phosphorous removal. A conventional activated sludge treatment facility has been designed along with a facility removing phosphorous by lime addition to primary clarifiers. Unit sizing, costs and energy requirements are compared and discussed.

Bench-Scale Testing of Activated Sludge Treatment for a TMP Wastewater

1993 ◽  
Vol 28 (3) ◽  
pp. 571-596 ◽  
Author(s):  
Susan F. Liver ◽  
Henry K. Miyamoto ◽  
Steve A. Black
Keyword(s):  
Activated Sludge ◽  
Full Scale ◽  
Operating Conditions ◽  
Cold Weather ◽  
Sludge Treatment ◽  
Bench Scale ◽  
Conventional Activated Sludge ◽  
Initial Batch ◽  
Treated Effluent ◽  
Biokinetic Parameters

Abstract A continuous bench-scale treatability study determined the most desirable design and operating parameters for waste treament of effluent from an integrated Canadian TMP newsprint operation. An initial batch study indicated that the effluent was biologically treatable and provided initial biological kinetic (biokinetic) parameters for this wastewater. This information was used to design the continuous study. Conventional activated sludge treatment of the mill wastewater can produce an effluent which meets the federal regulations for BOD5, suspended solids, and toxicity to D. magna. Predictions using cumulative toxicity units (CTU) indicate that the treated effluent would also be non-toxic to O. mykiss as well. Analyses of ammonia in the treated effluent indicated that un-ionized ammonia concentrations would be non-toxic to rainbow trout. Mass balances incorporating the results of the bench-scale studies and the effect of fibre carry-over from the primary clarifier, defined the full-scale operating conditions selected as: an F/M of 0.35 d−1, HRT of 0.5 days, SRT of 6 days and an MLSS of 4400 mg/L (when no polymer is used at the primary clarifier). These conditions were arrived at by selecting the smallest HRT which still corresponded to an MLSS < 5000 mg/L, an F/M < 0.4 d−1 and an SRT > 5 days. Based on the kinetics for biological treatment of mill effluent, at the maximum mill production, adequate BOD5 removal will still easily be obtained under the above operating conditions, even during cold weather periods. Operational concerns identified by bench-scale testing indicated that a full-scale facility should incorporate an anoxic selector (although the anoxic selector did not show measurable improvement in the bench-scale tests) and micronutrient addition for filamentous bulking control.

Process Improvement by Computer-Aided Load Smoothing in Activated Sludge Treatment

1989 ◽  
Vol 21 (10-11) ◽  
pp. 1225-1237 ◽  
Author(s):  
G. Naghdy ◽  
P. Helliwell
Keyword(s):  
Activated Sludge ◽  
Process Improvement ◽  
Pilot Plant ◽  
Arima Models ◽  
Sludge Treatment ◽  
Effluent Quality ◽  
Conventional Activated Sludge ◽  
Computer Aided ◽  
Smoothing Process

The benefits obtainable from smoothing flow and load to conventional activated sludge treatment units were examined in a large twin-stream pilot plant. Forecasting flow and load using ARIMA* models was found to lead to a reduction in the volume of storage required to permit flow and load smoothing. Process improvement, as mirrored in effluent quality, was achieved even when air feed was reduced by 25% to the smoothed stream.

Replacement of the Final Settling Basin by a Fluidized Pellet Bed Separator to Improve Efficiency of Activated Sludge System

1993 ◽  
Vol 27 (11) ◽  
pp. 253-256 ◽  
Author(s):  
Norihito Tambo ◽  
Genzou Ozawa ◽  
Yasuhiko Kihara ◽  
Akira Ohba
Keyword(s):  
Activated Sludge ◽  
Treatment System ◽  
High Rate ◽  
Sludge Treatment ◽  
Settling Basin ◽  
Separation Technology ◽  
Improve Efficiency ◽  
Conventional Activated Sludge ◽  
Activated Sludge System ◽  
Bed Separation

A new high rate separation technology, i.e. a fluidized pellet bed separation of activated sludge, is proposed to improve conventional activated sludge treatment system and the related dewatering process.

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