BNR Process using RAS Anaerobic Zone

2015 ◽  
Vol 2015 (3) ◽  
pp. 1-3 ◽  
Author(s):  
Gerry Stevens ◽  
Al Ellsworth ◽  
Mike Wyman ◽  
Angela Lambrecht
Keyword(s):  
Anaerobic Zone

The effect of anaerobic zone mixing on the performance of a three-stage Bardenpho plant

1998 ◽  
Vol 38 (1) ◽  
pp. 55-62 ◽  
Author(s):  
S. C. Williams ◽  
J. Beresford
Keyword(s):  
Detrimental Effect ◽  
Flow Characteristic ◽  
Tracer Tests ◽  
Poor Performance ◽  
Phosphorus Concentration ◽  
Effluent Quality ◽  
Mixing Energy ◽  
The United Kingdom ◽  
Low Phosphorus ◽  
Anaerobic Zone

Thames Water have built a three-stage Bardenpho activated sludge plant to treat 50% of the wastewater flow at Slough in the United Kingdom. Following commissioning, the plant performed well in terms of nitrification and denitrification but did not produce an effluent with a low phosphorus concentration. One possible explanation for the poor performance was the mixing of the anaerobic zone. The flow characteristic of the anaerobic zone was identified by tracer tests and alternative mixing regimes were tested. The results showed that reducing the mixing energy in the anaerobic zone had no detrimental effect on the effluent quality. The plant has operated with the reduced mixing input for nine months and the effluent phosphorus concentration has been reduced from 2.1 mgl−1 to 0.8 mgl−1.

Experimental Study on the Optimal Thickness of Infiltration Media of the CRI System

2011 ◽  
Vol 415-417 ◽  
pp. 1703-1707
Author(s):  
Jun Min Chen ◽  
Xiao Lin Yao
Keyword(s):  
Experimental Study ◽  
Removal Efficiency ◽  
Significant Influence ◽  
Soil Column ◽  
Experimental Results ◽  
Artificial Soil ◽  
Optimal Thickness ◽  
Effluent Quality ◽  
Anaerobic Zone

Abstract. In order to investigate the optimal thickness of infiltration media in the Constructed Rapid Infiltration System, the artificial soil column is used to simulate the Constructed Rapid Infiltration System, and the CODCr, NH3-N and TN concentrations of the effluent from all the sampling sites are monitored. The experimental results and analysis show that the thickness of infiltration media exerts a significant influence on the CODCr, NH3-N and TN concentration and removal efficiency of the effluent; the CODCr, NH3-N and TN are mainly removed in the 0-1800mm zone of the artificial soil column; the total CODCr removal efficiency increases, as the thickness of infiltration media increases, but the CODCr removal efficiency in the 1800-2200mm zone is very low; the NH3-N and TN removal efficiency reaches the maximum where the thickness of infiltration media is 1800mm; the NH3-N and TN concentration of the effluent from 1800-2200mm zone dose not decrease, but increase 5-8%, due to the assimilation denitrification and amemoniation reaction on the end of the anaerobic zone; in consideration of the effluent quality, efficient biodegradation zone, construction investment, etc. the optimal thickness of infiltration media in CRI system should be 1800mm.

A Study on the Ammonia Removal Mechanisms for the A/O Biological Nitrogen Removal Process with the Enhancement of the Zeolite

2011 ◽  
Vol 322 ◽  
pp. 52-56 ◽  
Author(s):  
Guan Wen Cheng ◽  
Wen Yuan Wei ◽  
Guo Dan Lu ◽  
Zhi Chao Wu ◽  
Xiang Feng Huang ◽  
...  
Keyword(s):  
Ammonia Removal ◽  
Biological Nitrogen Removal ◽  
Secondary Treatment ◽  
Activated Sludge Process ◽  
Adsorbate Concentration ◽  
Oxic Zone ◽  
Carbon Nitrogen Ratio ◽  
Nitrogen Ratio ◽  
Anaerobic Zone ◽  
Biological Nitrogen

This paper mainly studied on using activated sludge process with zeolite to upgrade the traditional secondary treatment plants. In this process, zeolite acted as ammonian sorbent and microbial carrier firstly, and then composed zeolite and biological complex to improve denitrification of anaerobic zone and nitrification of oxic zone. In the anaerobic zone, the influent contained a lot higher ammonian concentration. The zeolite adsorbed ammonian, it increased carbon nitrogen ratio and facilitated denitrification. While in the oxic zone, adsorbate concentration of mixed liquid decreased owing to biodegra dation by the action of salinity and microorganism. Thus, it striked a balance between adsorption and desorption of zeolite with ammonium, and zeolite with ammonium released constantly ammonian to renew.

Substrate interactions during aerobic biodegradation of methane, ethene, vinyl chloride and 1,2-dichloroethenes

2001 ◽  
Vol 43 (5) ◽  
pp. 333-340 ◽  
Author(s):  
D. L. Freedman ◽  
A. S. Danko ◽  
M. F. Verce
Keyword(s):  
Vinyl Chloride ◽  
Natural Attenuation ◽  
Enrichment Culture ◽  
Active Role ◽  
Aerobic Biodegradation ◽  
Aerobic Conditions ◽  
Lag Period ◽  
Anaerobic Zone ◽  
Set Up ◽  
Cis And Trans

Intrinsic biodegradation of trichloroethene and 1,1,1-trichloroethane in groundwater at a Superfund site in California has been observed. An anaerobic zone exists in the area closest to the source location, yielding the expected complement of reductive dechlorination daughter products, including cis-1,2-dichloroethene (cis-DCE) and vinyl chloride (VC). Significant levels of methane and ethene were also generated in the anaerobic zone. The groundwater returns to aerobic conditions downgradient of the source, with methane, ethene, VC, and several other compounds still present. Attenuation of VC in the aerobic zone suggests that it is being biodegraded. In this study microcosms were used to evaluate the role of methane and ethene as primary substrates for aerobic biodegradation of VC. Biodegradation of VC was fastest in the bottles containing ethene, with 40 μmol of VC consumed over a 150 day period, compared to approximately 15–20 μmol with methane or a mixture of methane and ethene. VC did not noticeably inhibit ethene biodegradation but did slow the rate of methane use. Methane inhibited ethene metabolism, which apparently caused a reduction in VC biodegradation when methane was present with ethene. These results suggest that ethene plays an important role during in situ natural attenuation of VC under aerobic conditions. Microcosms were also set up with VC alone. Following a 75 day lag period, VC consumption began and subsequent additions were consumed without a lag, suggesting the presence of organisms capable of using VC as a growth substrate. After providing VC alone for nearly 400 days, aliquots of the enrichment culture were used to evaluate its ability to biodegrade cis- and trans-DCE. Both compounds were readily consumed, although addition of VC as the primary substrate was needed to sustain biodegradation of repeated additions. This result suggests that organisms capable of using VC as a sole substrate may play an active role in aerobic natural attenuation of DCEs.

Saving phosphorus removal at the Henderson NV plant

2012 ◽  
Vol 65 (7) ◽  
pp. 1318-1322 ◽  
Author(s):  
J. Barnard ◽  
D. Houweling ◽  
H. Analla ◽  
M. Steichen
Keyword(s):  
Fatty Acids ◽  
Phosphorus Removal ◽  
Volatile Fatty Acids ◽  
Biological Phosphorus Removal ◽  
Case Histories ◽  
Mixed Liquor ◽  
Removal Process ◽  
Low Levels ◽  
Anaerobic Zone ◽  
Biological Phosphorus

While the mechanism of biological phosphorus removal (BPR) and the need for volatile fatty acids (VFA) have been well researched and documented to the point where it is now possible to design a plant with a very reliable phosphorus removal process using formal flow sheets, BPR is still observed in a number of plants that have no designated anaerobic zone, which was considered essential for phosphorus removal. Some examples are given in this paper. A theory is proposed and then applied to solve problems with a shortage of VFA in the influent of the Henderson NV plant. Mixed liquor was fermented in the anaerobic zone, which resulted in phosphorus removal to very low levels. This paper will discuss some of the background, and some case histories and applications, and present a simple postulation as to the mechanism and efforts at modelling the results.

Monitoring the influence of toxic compounds on microbial denitrifying biofilm processes

2003 ◽  
Vol 47 (5) ◽  
pp. 211-216 ◽  
Author(s):  
J. Li ◽  
P.L. Bishop
Keyword(s):  
Organic Compound ◽  
Redox Potential ◽  
Organic Compounds ◽  
Acid Orange 7 ◽  
Toxic Compounds ◽  
Acid Orange ◽  
Anoxic Layer ◽  
Anaerobic Zone ◽  
Microelectrode Measurements

Microelectrode measurements were conducted to obtain nitrate, pH and redox potential profiles within anoxic denitrifying biofilms. The influence of a toxic organic compound (acid orange 7) on biofilm microprofiles was also monitored using microelectrodes. The data provide evidence that the denitrifying biofilms were stratified into an anoxic layer and an anaerobic layer. The anaerobic zone might provide a niche for the biodegradation of recalcitrant organic compounds in biofilms. It was found that acid orange 7 and its biodegradation byproducts had only a slight impact on biofilm nitrate, pH and redox potential profiles.

scholarly journals Plantwide modelling – anaerobic digestion of waste sludge from parent nutrient (N and P) removal systems

Water SA ◽  
2019 ◽  
Vol 45 (3 July) ◽  
Author(s):  
DS Ikumi ◽  
GA Ekama
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Volatile Fatty Acids ◽  
Treatment Plant ◽  
Anaerobic Digester ◽  
Hydrolysis Rate ◽  
Biological Nutrient Removal ◽  
Biomass Hydrolysis ◽  
Behavioural Patterns ◽  
Anaerobic Zone

Wastewater treatment plant (WWTP) mathematical models are based on the behavioural patterns of microorganisms involved in the treatment process. These microorganisms are assumed incapable of thinking or planning but simply act according to the capabilities afforded to them by their surrounding conditions – hence different microorganisms pre-dominate different WWTP zones according to how well the conditions suit them. When waste activated sludge (WAS) from biological nutrient removal (BNR) activated sludge (AS) systems, containing phosphorus-accumulating organisms (PAOs), is fed to an anaerobic digester, there is a release of high quantities of metals, phosphorus (P) and nitrogen (N). The manner in which we model the release of these metals and nutrients significantly affects the accuracy of predicted anaerobic digestion (AD) outcomes. Previous studies of PAOs show that in the anaerobic zone of the AS system, they can form energy-rich poly3-hydroxybutyrate (PHB) at the expense of their aerobically generated polyphosphate (PP). Thus, it is expected that the PAOs containing PP sent into an anaerobic digester with volatile fatty acids (VFAs) present, would utilize their PP reserves as they would in the anaerobic zone of an AS process ending up with formation and storage of some PHB. Ultimately, all the stored products of the PAO get released, since there is no alternating aerobic environment to cater for their growth. Since it has been established that the PP release in the AD occurs much faster than the PAO biomass hydrolysis rate, it is modelled as a separate process. Steps are presented in the development of this PP release mass-balanced stoichiometries that occur with AD of PAOs. By comparing outcomes from these proposed stoichiometries against measured experimental data, it is noticed that better predictions are obtained with acetate uptake for PHB formation than when modelling the AD PP release to occur with PAO death and hydrolysis.

Research on the Influence Factors of the Biological Phosphorus Removal in Carrousel Oxidation Ditch Process

2011 ◽  
Vol 356-360 ◽  
pp. 2169-2174
Author(s):  
Zhou Fang Guo ◽  
Hua Zhang ◽  
Jin Hu ◽  
Xiao Wu Huang ◽  
Yang Luo
Keyword(s):  
Phosphorus Removal ◽  
Influence Factors ◽  
Treatment Plant ◽  
Phosphorus Release ◽  
Engineering Practice ◽  
Oxidation Ditch ◽  
Biological Phosphorus Removal ◽  
Important Indicator ◽  
Anaerobic Zone ◽  
Carrousel Oxidation Ditch

Abstract: The concentration of total phosphorus(P-tot) in effluent is an important indicator of the effect of wastewater treatment plant(WWTP), excessive discharge of phosphorus will result in the tender eutrophication of natural water and other ecological pollution problems. In this paper, Qilidian WWTP in Guilin for the study object, researched Carrousel oxidation ditch process of the plant DO, pH, nitrate, BOD5 and P-tot in influent, and P-tot in influent and in effluent of the final clarifier, systems analyzed the factors and reasons affecting phosphorus removal. The result of the research shows itself as follows: the dissolved oxygen (DO) in oxidation ditch anaerobic zone above 0.5mg/l and at the end of the aerobic zone up to 3.87mg/l are not suitable for phosphorus accumulating organisms (PAOs) to release phosphorus; in the influent, B0D5/P-tot<20, carbon source used for PAOs in the sewage is insufficient; the concentration of P-tot in the effluent is higher than that in the influent, there occurs an obvious phenomenon of phosphorus release in the final clarifier. In addition, the pH in oxidation ditch ranges from 6.82 to7.19 and the concentration of nitrate in anaerobic zone below 0.2mg/l are suitable for the phosphorus removal process. This research provide technical support for the similar oxidation ditch process of upgrading and transformation,and have a higher value in engineering practice.

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