Integration of performance, molecular biology and modeling to describe the activated sludge process

1998 ◽  
Vol 37 (4-5) ◽  
pp. 223-229 ◽  
Author(s):  
V. Urbain ◽  
B. Mobarry ◽  
V. de Silva ◽  
D. A. Stahl ◽  
B. E. Rittmann ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Molecular Biology ◽  
Activated Sludge ◽  
Residence Time ◽  
Municipal Wastewater ◽  
Treated Wastewater ◽  
Integrated Analysis ◽  
Activated Sludge Process ◽  
Hydraulic Residence Time ◽  
Technical Problems

To study process performance and population dynamics in activated sludge, a pilot-scale Membrane Bioreactor (MBR) was installed in a municipal wastewater treatment plant (Aubergenville, France). Since no solids losses occur in the MBR effluent, the sludge residence time (SRT) can be: i) easily controlled by means of the sludge withdrawal, and ii) dissociated from the hydraulic residence time (HRT). A complete characterization of this activated sludge system was performed at three sludge ages (5, 10 and 20 days). Raw and treated wastewater quality, as well as sludge concentration, was analyzed, nucleic probe analysis was performed to determine the heterotrophic and nitrifier populations, and the results were compared to the output from a multispecies model that integrates substrate removal kinetics and soluble microbial products (SMP) production/consumption. This paper presents an integrated analysis of the activated sludge process based on chemical, molecular biology, and mathematical tools. The model was able to describe the MBR system with a high degree of accuracy, in terms of COD removal and nitrification, as well as sludge production and population dynamics through the ratio of active nitrifiers/bacteria. Both steady-state and transient conditions could be described accurately by the model, except for technical problems or sudden variations in the wastewater composition.

Enhancing nitrification in North American activated sludge plants

2000 ◽  
Vol 41 (9) ◽  
pp. 97-105 ◽  
Author(s):  
G.T. Daigger ◽  
D.S. Parker
Keyword(s):  
Activated Sludge ◽  
Residence Time ◽  
North American ◽  
Biological Process ◽  
Full Scale ◽  
Activated Sludge Process ◽  
Hydraulic Residence Time ◽  
Nitrification Process ◽  
Mechanistic Basis ◽  
Space Requirements

Many plant owners, operators and designers consider the nitrifying activated sludge process as being a high hydraulic residence time (HRT) process. However, in recent years a number of techniques have been developed to enhance the performance of activated sludge plants for nitrification. The result, when the proper combination of these techniques is used, can be a significant reduction in the biological process hydraulic residence time and a corresponding reduction in facility costs and space requirements. Several of these factors are discussed in this paper, including a discussion of the mechanistic basis for each technique and its impact on nitrification process sizing. Some full-scale North American examples are also discussed.

Biological nutrient removal at a very low-loaded activated sludge plant with high biomass concentrations

1998 ◽  
Vol 38 (1) ◽  
pp. 63-70 ◽  
Author(s):  
H. J. Kiuru ◽  
J. A. Rautiainen
Keyword(s):  
Activated Sludge ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Nitrogen Removal ◽  
Nutrient Removal ◽  
Municipal Wastewater ◽  
Treated Wastewater ◽  
Biological Nutrient Removal ◽  
Activated Sludge Process ◽  
Biological Phosphorus

The Laboratory of Environmental Engineering at the Helsinki University of Technology (HUT) carried out in 1991-1995 two successive full-scale research and development projects at the Pihlajaniemi WWTP of Savonlinna concerning biological nutrient removal from municipal wastewater. The projects have resulted in two reports in Finnish with quite large English summaries. This WWTP was constructed originally (1978) as a conventional low-loaded activated sludge plant with the simultaneous precipitation of phosphorus. It was dimensioned for a sludge concentration of 3.5 kgMLSS/m3 in the aeration tanks. Six years later (1984) the plant was fitted with a tertiary stage of flotation filters in order to improve the removal of suspended solids and phosphorus. Nitrification was introduced to the activated sludge process of the plant in 1987. It could be done without any extension by using the sludge concentrations of 6-10 kgMLSS/m3 in the aeration tanks. In that way, this activated sludge process was converted into a very low-loaded one. The process became able to nitrify totally in the circumstances in which the wastewater temperature varies at the range of 4-20°C. The actual hydraulic as well as the BOD7-load of the plant are about 40% of the original dimensioned ones. This activated sludge process of the Pihlajaniemi WWTP was modified in 1991-1993 for nitrogen removal and then in 1994-1995 for both biological phosphorus and nitrogen removal Denitrification was introduced to the process and the simultaneous precipitation of phosphorus in that was replaced by biological phosphorus removal still without any extension of the activated sludge process. The plant has now been operated over four years with biological nutrient removal exploiting the organic carbon compounds of the wastewater. A very little addition of some precipitant is used to improve the biological removal of phosphorus. The chemical and energy cost of the plant has been reduced by some 50% due to the introduction of biological nutrient removal. The BOD7-value of the treated wastewater is mainly less than 3 mg/l (always less than 5 mg/l). The content of total phosphorus in the treated wastewater is usually less than 0.3 mg/l (always less than 0.5 mg/l). The content of total nitrogen in the treated wastewater is mainly 8-12 mg/l. Reductions for BOD7 and total phosphorus over 95% as well as that for total nitrogen about 70% are achieved.

Dynamic modeling of nitrogen removal for a three-stage integrated fixed-film activated sludge process treating municipal wastewater

2017 ◽  
Vol 41 (2) ◽  
pp. 237-247 ◽  
Author(s):  
Paul Moretti ◽  
Jean-Marc Choubert ◽  
Jean-Pierre Canler ◽  
Pierre Buffière ◽  
Olivier Pétrimaux ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Dynamic Modeling ◽  
Nitrogen Removal ◽  
Municipal Wastewater ◽  
Activated Sludge Process ◽  
Fixed Film

scholarly journals Microalgae as biological treatment for municipal wastewater – effects on the sludge handling in a treatment plant

2018 ◽  
Vol 78 (3) ◽  
pp. 644-654 ◽  
Author(s):  
J. Olsson ◽  
S. Schwede ◽  
E. Nehrenheim ◽  
E. Thorin
Keyword(s):  
Heavy Metals ◽  
Activated Sludge ◽  
Biological Treatment ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Waste Activated Sludge ◽  
Activated Sludge Process ◽  
Primary Sludge ◽  
Thermophilic Conditions ◽  
Mesophilic Conditions

Abstract A mix of microalgae and bacteria was cultivated on pre-sedimented municipal wastewater in a continuous operated microalgae-activated sludge process. The excess material from the process was co-digested with primary sludge in mesophilic and thermophilic conditions in semi-continuous mode (5 L digesters). Two reference digesters (5 L digesters) fed with waste-activated sludge (WAS) and primary sludge were operated in parallel. The methane yield was slightly reduced (≈10%) when the microalgal-bacterial substrate was used in place of the WAS in thermophilic conditions, but remained approximately similar in mesophilic conditions. The uptake of heavy metals was higher with the microalgal-bacterial substrate in comparison to the WAS, which resulted in higher levels of heavy metals in the digestates. The addition of microalgal-bacterial substrate enhanced the dewaterability in thermophilic conditions. Finally, excess heat can be recovered in both mesophilic and thermophilic conditions.

Removal Efficiency of Environmental Endocrine Disrupting Chemicals Pollutants-Phthalate Esters in Northern WWTP

2013 ◽  
Vol 807-809 ◽  
pp. 694-698
Author(s):  
Rong Xin Huang ◽  
Zhen Xing Wang ◽  
Gang Liu ◽  
Qi Jin Luo
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Municipal Wastewater ◽  
Removal Rate ◽  
Phthalate Esters ◽  
Endocrine Disrupting Chemicals ◽  
Treatment Plant ◽  
Activated Sludge Process ◽  
Wastewater Reclamation ◽  
Conventional Activated Sludge

In order to guarantee the reliability and security of reclaiming water, research on the removal efficiency of the environmental endocrine chemicals (EDCs) --the Phthalate Esters (PAEs) in conventional secondary activated sludge and wastewater reclamation and reuse process was undergoing at Harbin wastewater treatment plant (WWTP). The wastewater samples were colleted from every unit effluent of WWTP. The results showed that contamination of EDCs were presented in municipal wastewater at Harbin and the concentrations of the four PAEs were 21.01μg/L for Di-n-butyl Phthalate (DBP); 9.63μg/L for Di-n-octyl Phthalate (DnOP); 4.56μg/L for Diethyl Phthalate (DEP); 1.96μg/L for Dimethyl Phthalate (DMP) respectively in the influent. The conventional activated sludge has good removal efficiencies performance on DMP, DEP and DBP. With the increasing of molecular weight and branch chains of PAEs contaminations, the removal rate of the four PAEs in the conventional activated sludge process decreased from 99.82%(DMP)，90.60%(DEP)，90.10%(DBP) to the only 45.13% removal rate for DnOP, which was mostly removed from primary treatment but no from secondary activated sludge process; Coagulation-air flotation plus filtration process was not a feasible way to remove PAEs from reclaiming treatment units.

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