A pilot study on a step-feeding anoxic/oxic activated sludge system

2006 ◽  
Vol 53 (9) ◽  
pp. 95-101 ◽  
Author(s):  
Wang Sheping ◽  
Yu Lifang ◽  
Han Guanghui ◽  
Zhu Hairong ◽  
Peng Dangcong
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Nutrient Removal ◽  
Municipal Wastewater ◽  
Cost Effective ◽  
Biological Nutrient Removal ◽  
Municipal Wastewater Treatment ◽  
Reactor Performance ◽  
Effective Technology ◽  
Total Average

A four stage pilot plant of step-feed biological nutrient removal (BNR) was employed to investigate reactor performance and process stability. The results obtained showed that step-feed BNR is efficient and cost-effective for nitrogen and carbonaceous removal from municipal wastewater. The total average removal efficiencies of COD, NH3-N, TN and TP could reach as high as 89.5, 97.8, 73 and 75%, respectively, with 50% of return activated sludge (RAS), 9 h of hydraulic retention time (HRT) and 20 d of sludge retention time (SRT). Step-feed BNR is an alternative and effective technology of nutrient removal for municipal wastewater treatment.

scholarly journals The bottlenecks and causes, and potential solutions for municipal sewage treatment in China

2020 ◽  
Vol 15 (1) ◽  
pp. 160-169 ◽  
Author(s):  
Yeshi Cao ◽  
M. C. M. Van Loosdrecht ◽  
Glen. T. Daigger
Keyword(s):  
Wastewater Treatment ◽  
Nutrient Removal ◽  
Urban Areas ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Integrated Design ◽  
Cost Effective ◽  
Municipal Sewage ◽  
Municipal Wastewater Treatment

Abstract Since about the 1990s China has achieved remarkable progress in urban sanitation. The country has built very extensive infrastructure for wastewater treatment, with 94.5% treatment coverage in urban areas and legally mandated nation-wide full nutrient removal implemented. However, municipal wastewater treatment plants (WWTPs) in China are still confronted with issues rooted in the unique sewage characteristics. This study compares energy recovery, cost of nutrient removal and sludge production between Chinese municipal WWTPs and those in countries with longer wastewater treatment traditions, and highlights the cause-effect relationships between Chinese sewage characteristics – high inorganic suspended solids (ISS) loads, and low COD and C/N ratio, and municipal WWTP process performance in China. Integrated design and operation guidelines for municipal WWTPs are imperative in relation to the unique sewage characteristics in China. Cost-effective measures and solutions are proposed in the paper, and the potential benefits of improving the sustainability of municipal WWTPs in China are estimated.

Mathematical Modeling of Aerobic Membrane Bioreactor (MBR) Using Hybrid Activated Sludge Model No. 3 (ASM3)

2010 ◽  
Vol 113-116 ◽  
pp. 1424-1428
Author(s):  
Yu Tian ◽  
Lin Chen ◽  
Xin Ying Su ◽  
Chu Qing Cao
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Recent Trend ◽  
Trial And Error ◽  
Municipal Wastewater Treatment ◽  
Sludge Retention Time ◽  
Microbial Products ◽  
Operating Strategies

Recent trend for membrane bioreactor (MBR) operation was to apply a low sludge retention time (SRT) to decrease the fouling propensity and simplify the overall maintenance. However, the correct control and operation of MBRs under low SRT conditions were not well-established. In this study, modeling of MBR system for municipal wastewater treatment was evaluated using hybrid Activated Sludge Models 3 (ASM3), which helped in determining the control and operating strategies. The experiment-based, manual trial-and-error approach used to calibrate the hybrid ASM3 was verified to be useful for MBR modeling at 30 d sludge retention time (SRT). Furthermore, the consistency relationships among carbon oxygen demanded (COD), soluble microbial products (SMP) and mixed liquor suspended solids (MLSS) were established in the process of modeling, implying that the accurate simulation of MLSS were the prerequisites for the COD and SMP prediction.

Removal of ibuprofen from wastewater: comparing biodegradation in conventional, membrane bioreactor, and biological nutrient removal treatment systems

2008 ◽  
Vol 57 (1) ◽  
pp. 1-8 ◽  
Author(s):  
T.M. Smook ◽  
H. Zho ◽  
R.G. Zytner
Keyword(s):  
Nutrient Removal ◽  
Rate Constants ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Aerobic Biodegradation ◽  
Biological Nutrient Removal ◽  
Aeration Tank ◽  
Municipal Wastewater Treatment ◽  
Pharmaceutical Removal

Pharmaceuticals are continually being introduced into the influent of municipal wastewater treatment plants (WWTPs). Developing a better understanding of pharmaceutical removal mechanisms within the different treatment processes is vital in preventing downstream contamination of our water resources. In this study, ibuprofen, a popular over-the-counter pain reliever, was monitored by taking wastewater samples throughout the City of Guelph municipal WWTP. Greater than 95% of ibuprofen was found to be removed in the aeration tank, with aerobic biodegradation being the dominant mechanism. For comparison, first-order kinetics were used to quantify ibuprofen biodegradation in a conventional WWTP aeration tank and in a membrane bioreactor (MBR) pilot plant. The rate constants, kbiol, for the conventional tank and the MBR were determined to be (−6.8±3.3) L/g SS*d and (−8.4±4.0) L/g SS*d, respectively. These two rate constants were found to be statistically similar. Preliminary study of a biological nutrient removal pilot system also suggests that ibuprofen can be anaerobically degraded.

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.

The combined effects of carbon/nitrogen ratio, suspended biomass, hydraulic retention time and dissolved oxygen on nutrient removal in a laboratory-scale anaerobic–anoxic–oxic activated sludge biofilm reactor

2017 ◽  
Vol 77 (1) ◽  
pp. 248-259 ◽  
Author(s):  
D. S. Manu ◽  
Arun Kumar Thalla
Keyword(s):  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Retention Time ◽  
Nutrient Removal ◽  
Hydraulic Retention Time ◽  
Appropriate Technology ◽  
Biofilm Reactor ◽  
Operating Conditions ◽  
Biological Nutrient Removal ◽  
Suspended Biomass

Abstract The current trend in sustainable development deals mainly with environmental management. There is a need for economically affordable, advanced treatment methods for the proper treatment and management of domestic wastewater containing excess nutrients (such as nitrogen and phosphorus) which can cause eutrophication. The reduction of the excess nutrient content of wastewater by appropriate technology is of much concern to the environmentalist. In the current study, a novel integrated anaerobic–anoxic–oxic activated sludge biofilm (A2O-AS-biofilm) reactor was designed and operated to improve the biological nutrient removal by varying reactor operating conditions such as carbon to nitrogen (C/N) ratio, suspended biomass, hydraulic retention time (HRT) and dissolved oxygen (DO). Based on various trials, it was seen that the A2O-AS-biofilm reactor achieved good removal efficiencies with regard to chemical oxygen demand (95.5%), total phosphorus (93.1%), ammonia nitrogen concentration (NH4+-N) (98%) and total nitrogen (80%) when the reactor was maintained at C/N ratio of 4, suspended biomass of 3 to 3.5 g/L, HRT of 10 h, and DO of 1.5 to 2.5 mg/L. Scanning electron microscopy (SEM) of suspended and attached biofilm showed a dense structure of coccus and bacillus bacteria with the diameter ranging from 0.3 to 1.2 μm. The Fourier transform infrared (FTIR) spectroscopy results indicated phosphorylated macromolecules and carbohydrates mix or bind with extracellular proteins in exopolysaccharides.

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.

Sign in / Sign up

Export Citation Format

Share Document