Long-Term Effects of Copper Nanoparticles on Wastewater Biological Nutrient Removal and N2O Generation in the Activated Sludge Process

2012 ◽  
Vol 46 (22) ◽  
pp. 12452-12458 ◽  
Author(s):  
Yinguang Chen ◽  
Dongbo Wang ◽  
Xiaoyu Zhu ◽  
Xiong Zheng ◽  
Leiyu Feng
Keyword(s):  
Activated Sludge ◽  
Copper Nanoparticles ◽  
Nutrient Removal ◽  
Biological Nutrient Removal ◽  
Activated Sludge Process ◽  
Long Term Effects

Microbial evaluation of activated sludge and filamentous population at eight Czech nutrient removal activated sludge plants during year 2000

2002 ◽  
Vol 46 (1-2) ◽  
pp. 471-478 ◽  
Author(s):  
O. Krhutková ◽  
I. Ruzicková ◽  
J. Wanner
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Microbial Population ◽  
Point Of View ◽  
Biological Nutrient Removal ◽  
Filamentous Microorganisms ◽  
Microthrix Parvicella ◽  
Year 2000 ◽  
The Relationship

The long-term project on the survey of filamentous microorganisms, which started in 1996, was finished in 2000 by the survey of eight Czech activated sludge plants with biological nutrient removal (BNR) systems. At all plants with enhanced biological nutrient removal, specific microbial population (mostly from the point of view of filaments occurrence), operational problems (presence of biological foaming, bulking) and plant operation were observed periodically and longer than 1 year. In our paper the relationship between the composition of activated sludge (especially filaments) consortia and modification of the process with nutrient removal is discussed. At the surveyed plants Type 0092 and Microthrix parvicella were identified as dominant Eikelboom filamentous types.

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.

Comparison of Yields and Decay Rates for a Biological Nutrient Removal Process and a Conventional Activated Sludge Process

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2195-2198 ◽  
Author(s):  
S. A. McClintock ◽  
V. M. Pattarkine ◽  
C. W. Randall
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Pilot Scale ◽  
Decay Rates ◽  
Growth Yields ◽  
Biological Nutrient Removal ◽  
Activated Sludge Process ◽  
Conventional Activated Sludge ◽  
Aerobic Process ◽  
Solids Retention

Two pilot-scale activated sludge reactors, one VIP (named after Virginia Initiative Plant) biological nutrient removal (BNR) process and one conventional, fully aerobic process, were operated over a range of solids retention times (SRT's) and under the same conditions so that growth yields and specific decay rates could be evaluated and compared. True growth yields (Y's) for the BNR and the conventional processes were equal and were 0.41 gVSS/gCOD. The specific decay rate, b, for the BNR process, 0.063 d, was lower than in the fully aerobic process, 0.110 d-1, indicating that decay occurs at a much lower rate in the anoxic and anaerobic zones of the BNR process.

Settling Characteristics of Activated Sludge in Danish Treatment Plants with Biological Nutrient Removal

1994 ◽  
Vol 29 (7) ◽  
pp. 157-165 ◽  
Author(s):  
Gert Holm Kristensen ◽  
Per Elberg Jørgensen ◽  
Per Halkjær Nielsen
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Volume Index ◽  
Biological Nutrient Removal ◽  
Sludge Volume Index ◽  
Filamentous Microorganisms ◽  
Best Parameter ◽  
One Year ◽  
Sludge Settling ◽  
Settling Characteristics

In 1989-91, a study was performed to investigate the settling characteristics of activated sludge in Danish treatment plants with biological nutrient removal. The study included three screening series on 38 treatment plants. Furthermore, the study included investigations during one year on seasonal variations in sludge settling characteristics at three treatment plants. The screening investigations were performed in November 1989 and May and September, 1990. Results showed that in the May-screening, 35-45% of the plants had a filament index of 2-2.5 or above, corresponding to a sludge volume index above 150 ml/g. When comparing data for diluted and non-diluted sludge volume indices, a SVI value of 150 ml/g seemed parallel to a DSVI of 110 ml/g. In the November- and September-screenings, some 30% of the plants had activated sludge showing a filament index in or above the critical area. Dominating filamentous microorganisms were found to be (in decreasing order): Microthrix parvicella, Type 0041, Type 021N, Type 0092, Type 0914, and Type 1851. A distinct variation over the year in sludge settling characteristics was found for the three plants. Sludge settling characteristics improved during summer, and deteriorated during winter. For activated sludge with a high content of filamentous microorganisms, the best parameter to follow the variations in sludge settling properties was the filament number. If the activated sludge concentration, the MLSS, varied significantly, the specific filament number was to be applied.

Difficulties and developments in biological nutrient removal technology and modelling

1999 ◽  
Vol 39 (6) ◽  
pp. 1-11 ◽  
Author(s):  
George A. Ekama ◽  
Mark C. Wentzel
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
P Uptake ◽  
Biological Nutrient Removal ◽  
Filamentous Bulking ◽  
Recent Developments ◽  
Removal Technology ◽  
Hydrolysis Of ◽  
Activated Sludge Systems ◽  
P Removal

Filamentous bulking and the long sludge age required for nitrification are two important factors that limit the wastewater treatment capacity of biological nutrient removal (BNR) activated sludge systems. A growing body of observations from full-scale plants indicate support for the hypothesis that a significant stimulus for filamentous bulking in BNR systems in alternating anoxic-aerobic conditions with the presence of oxidized nitrogen at the transition from anoxic to aerobic. In the DEPHANOX system, nitrification takes place externally allowing sludge age and filamentous bulking to be reduced and increases treatment capacity. Anoxic P uptake is exploited in this system but it appears that this form of biological excess P removal (BEPR) is significantly reduced compared with aerobic P uptake in conventional BNR systems. Developments in the understanding of the BEPR processes of (i) phosphate accumulating organism (PAO) denitrification and anoxic P uptake, (ii) fermentation of influent readily biodegradable (RB)COD and (iii) anaerobic hydrolysis of slowly biodegradable (SB)COD are evaluated in relation to the IAWQ Activated Sludge Model (ASM) No.2. Recent developments in BEPR research do not yet allow a significant improvement to be made to ASM No. 2 that will increase its predictive power and reliability and therefore it remains essentially as a framework to guide further research.

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