Congruence in the performance of model nitrifying activated sludge plants located in Germany, Scotland and Spain

Christofi, N.; Aspichueta, E.; Dalzell, David J.B; Sota, Alejandro de la; Etxebarría, Javier; Fernandes, Teresa F.; Gutiérrez, Mónica; Morton, J.; Obst, U.; Schmellenkamp, Peter

doi:10.1016/s0043-1354(02)00119-7

Cited by 11 publications

(7 citation statements)

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“…Activated sludge from Leixlip I WWTP was used to seed the reactors at start-up. The reactors were operated with a food-to-microorganism (f/m) ratio of 0.13 kg COD kg -1 day -1 using the synthetic wastewater described above, with sodium bicarbonate (NaHCO 3 ) added to final concentration of 0.3 g L -1 synthetic wastewater to prevent a drop in pH due to nitrification (Christofi et al 2003). Distilled, deionized water was used to prepare the synthetic wastewater and for dilution to the desired COD.…”

Section: Acclimatization Proceduresmentioning

confidence: 99%

“…Rather than demonstrating a higher tolerance to shock loads of metal contaminants, the activated sludge from the industrial WWTP (Leixlip II) was more inhibited by AMD than activated sludge from municipal WWTPs. It is likely that the population of microorganisms in the industrial sludge has adapted to the presence of a specific industrial effluent (Christofi et al 2003), and consequently has a decreased resilience to shock loads of other toxicants. Using activated sludge from WWTPs treating MWW can ensure that the population of microorganisms has not become adapted to a specific industrial wastewater and is therefore more robust to changes in metal concentrations or pH shocks caused by adding AMD.…”

Section: Acute Toxicity Testsmentioning

confidence: 99%

“…The sensitivity of activated sludge to different toxic substances can be influenced by previous exposure and acclimatization: the population of microorganisms can be modified and selected owing to the presence of industrial effluents (Christofi et al 2003). Alternatively, the activated sludge bacteria can adapt to protect themselves; Guibaud et al (2005) observed increased metal binding capacity by EPS produced by activated sludge microorganisms that had been exposed to Cd, Pb, and Ni, when compared to EPS on pure bacterial cultures that had not been previously exposed to metals.…”

Section: Introductionmentioning

confidence: 99%

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Acute and Chronic Toxicity of Acid Mine Drainage to the Activated Sludge Process

Hughes

Gray

2012

Mine Water Environ

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The combined treatment of acid mine drainage (AMD) and municipal wastewater using the activated sludge process is an innovative approach to AMD remediation. The toxicity of synthetic AMD to activated sludge was evaluated using oxygen uptake rate (OUR) inhibition tests, which showed that activated sludge can withstand high proportions of AMD (EC 50 19-52% AMD by volume). The EC 50 values of municipal and industrial activated sludges were significantly different (p \ 0.05), with municipal sludges exhibiting higher tolerance to AMD. Although the EC 50 values for heterotrophic and nitrifying activated sludges were not statistically significantly different, the EC 50 values for heterotrophic bacteria were generally higher. Laboratory-based sequencing batch reactors were used to examine the treatability of AMD. Increased concentrations of COD and suspended solids, associated with turbidity and poor floc morphology, were observed in the final effluent after extended AMD loading. Protozoan community structure changed during the AMD loading period, and overall abundance tended to decrease over time. OUR decreased in the AMD-loaded reactors, particularly in the reactor receiving the highest AMD load, indicating reduced biomass activity over the acclimatization period. Results from OUR inhibition tests on the acclimatized activated sludge indicated that over a relatively short timescale (21 days), the activated sludge microbial community can adapt to AMD sufficiently so that shock loads of metals and acidity do not significantly inhibit OUR. These preliminary studies indicate that it is possible to treat AMD successfully in admixture with municipal wastewater using the activated sludge process.

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Section: Acclimatization Proceduresmentioning

confidence: 99%

Section: Acute Toxicity Testsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Acute and Chronic Toxicity of Acid Mine Drainage to the Activated Sludge Process

Hughes

Gray

2012

Mine Water Environ

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“…During each cycle, 1.7 L effluent was decanted and replaced with synthetic sewage (i.e., 50% volumetric exchange ratio) giving a HRT of 1 day (Ndon, 2007). OECD synthetic sewage (Christofi et al, 2003;Gendig et al, 2003) was used as the feed for the lab-scale plant. The 100-fold concentrated stock solution was stored at -sewage reservoir and to provide the desired sludge loading of 0.1 g BOD 5 g…”

Section: Laboratory-scale Sequencing Batch Reactors (Sbrs)mentioning

confidence: 99%

“…To avoided a decrease in the reactor pH during nitrification, as slightly acidic conditions are known to adversely affect the ciliate community (Cybis and Horan, 1997), NaHCO 3 was added to the synthetic sewage at a final concentration of 0.6 g L -1 (Christofi et al, 2003). The storage containers were kept cooled at an approximate temperature of 4-10˚C 100 to reduce bacterial growth and prevent degradation of the sewage.…”

Section: Laboratory-scale Sequencing Batch Reactors (Sbrs)mentioning

confidence: 99%

The effect of anoxia and anaerobia on ciliate community in biological nutrient removal systems using laboratory-scale sequencing batch reactors (SBRs)

Dubber

Gray

2011

Water Research

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Please cite this article as: Dubber, D., Gray, N.F. The effect of anoxia and anaerobia on ciliate community in biological nutrient removal systems using laboratory-scale sequencing batch reactors (SBRs), Water Research (2011Research ( ), doi: 10.1016Research ( /j.watres.2011 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractLittle is known about the effect of anaerobic and anoxic stages on the protozoan community in the activated sludge process and how this subsequently affects performance. Using a laboratory-scale BNR system the effect of different periods of anoxia on both the protozoan community and performance efficiency have been 15 examined. Four SBRs were operated at two cycles per day using a range of combined anoxic/anaerobic periods (0, 60, 120 to 200 min). Effluent quality (TOC, BOD, TP, TN, NH 4 -N, NO 3 -N and NO 2 -N), sludge settleability and ciliate community (species diversity and abundance) were analyzed over a periods of up to 24 days of operation. The species richness and total abundance of ciliates were found to decrease with longer 20 anoxic/anaerobic periods. Both, positive and negative significant correlations between the abundance of certain species and the period of anoxia was observed (e.g. Opercularia microdiscum, Epicarchesium granulatum), although other species (i.e. Acineria uncinata, Epistylis sp.) were unaffected by exposure to anoxia. In the laboratory-scale units, the 60 minute anoxic/anaerobic period resulted in good process performance (TOC and BOD 25 removal of 97 to 98% respectively), nitrification (80-90%), denitrification (52%) but poor levels of biological P removal (12%); with the protozoan community moderately affected but still diverse with high abundances. Increasing the length of anoxia to up to 200 min did not enhance denitrification although P removal rates increased to between 22-33%; however, ciliate species richness and total abundance both decreased and sludge 30 settleability became poorer. The study shows that activated sludge ciliate protozoa display a range of tolerances to anoxia that result in altered ciliate communities depending on the length of combined anoxic/anaerobic periods within the treatment process. It is recommended that anoxic/anaerobic periods should be optimized to sustain the protozoan community while achieving maximum performance and nutrient removal. 35

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2008

Pharma‐Ecology

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Congruence in the performance of model nitrifying activated sludge plants located in Germany, Scotland and Spain

Cited by 11 publications

References 12 publications

Acute and Chronic Toxicity of Acid Mine Drainage to the Activated Sludge Process

Acute and Chronic Toxicity of Acid Mine Drainage to the Activated Sludge Process

The effect of anoxia and anaerobia on ciliate community in biological nutrient removal systems using laboratory-scale sequencing batch reactors (SBRs)

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