scholarly journals Effect of Long-term Low Concentrations of TiO2 Nanoparticles on Dewaterability of Activated Sludge and the Relevant Mechanism: The Role of Nanoparticle Aging

2021 ◽  
Author(s):  
Chengyu Jiang ◽  
Qingjin Chen
Keyword(s):  
Activated Sludge ◽  
Batch Reactor ◽  
Sewage Treatment ◽  
Particle Surface ◽  
Scientific Management ◽  
Sludge Dewatering ◽  
Freshwater Environment ◽  
Low Concentrations ◽  
Concentration Levels

Abstract Nanoparticles can undergo aging phenomena that change their physical and chemical properties in sewage treatment systems. However, the effect of aged nanoparticles under long-term low concentrations on the dewatering performance of activated sludge in sewage treatment systems has not been reported yet. Here, we compared the chronic effects of pristine and aged TiO2 nanoparticles on sludge dewatering index including specific resistance to filtration (SRF) and bound water (BW) in the sequencing batch reactor (SBR) with the µg/L concentration levels and the relevant mechanisms were analyzed. The results show that the aging experiment in sludge supernatant could change the photosensitivity and water stability of nanoparticles, which was mainly due to the changes in the zeta potential and energy band of the particle, and ultimately attributed to the combined effect of particle surface inclusions such as organic matter and inorganic salt. At 10µg/L, nanoparticles could reduce the dewaterability of sludge, but at 100µg/L, nanoparticles could improve the dewaterability of sludge, because 10µg/L promoted the secretion of extracellular polymeric substance (EPS), regulated the structure of sludge flora and increased the abundance of secreting quorum sensing-acyl-homoserine lactones (QS-AHL) and EPS genera, while the corresponding exposure results of 100µg/L were the opposite, due to the damage and necrosis exposure effects of 100µg/L under long-term light, which reduced EPS production and increased sludge density. Interestingly, aging could alleviate the effects of two exposure concentrations on sludge dewatering, mainly being attributed to the decrease of the photoactivity of nanoparticles. The results of this study show that environmental aging could slow down, but cannot reverse the results of exposure to specific concentrations of nanoparticles. However, the ecological effects of photosensitive nanoparticles with two environmentally-relevant concentration levels of ug/L were significantly different, which should be refined and confirmed again in freshwater environment to provide a basis for subsequent scientific management and control of photosensitive nanoparticles.

Application of excess activated sludge ozonation in an SBR Plant. Effects on substrate fractioning and solids production

2008 ◽  
Vol 58 (1) ◽  
pp. 239-245 ◽  
Author(s):  
M. Naso ◽  
A. Chiavola ◽  
E. Rolle
Keyword(s):  
Activated Sludge ◽  
Organic Nitrogen ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Batch Tests ◽  
Plant Effects ◽  
Removal Processes ◽  
Biological Nitrogen ◽  
Ozonation Process

This paper provides new insights on the application of the ozonation process for the reduction of the activated sludge production in a sequencing batch reactor (SBR). The study was performed in two identical lab-scale SBRs plant, one for experimental activities (Exp SBR) and one used as control (Control SBR), both fed with domestic sewage. A fraction of the activated sludge collected from the Exp SBR at the end of the aerobic react phase was periodically subjected to ozonation for 30 minutes at three different specific dosages (0.05, 0.07 and 0.37 g O3/gSS) and then recirculated before the beginning of the following cycle. Recirculation of the ozonated sludge to the Exp SBR did not appreciably affect the efficiency of the biological nitrogen and carbon removal processes. Nonetheless, an improvement of the denitrification kinetic was observed. Mixed liquor volatile and suspended solids (MLSS and MLVSS, respectively) concentrations in the reactor decreased significantly with time for long term application of the ozonation treatment. Kinetic batch tests on unstressed sludge taken from Control SBR indicated that the different oxidant dosages (0.05, 0.07 and 0.37 g O3/gSS) and durations of the ozonation process (10, 20 and 30 minutes) used remarkably affected chemical oxygen demand (COD) and organic nitrogen fractioning. In particular, soluble and biodegradable fractions seemed to be higher at lower dosage and longer contact time.

scholarly journals Assessment of the biodegradability of polymer based on polyacrylates

2019 ◽  
Vol 58 (5) ◽  
pp. 44-48
Author(s):  
Leysan R. Galimzyanova ◽  
◽  
Tatiana V. Vdovina ◽  
Yoldyz V. Kobeleva ◽  
Natalia V. Galkina ◽  
...  
Keyword(s):  
Waste Water ◽  
Acrylic Acid ◽  
Activated Sludge ◽  
Respiratory Activity ◽  
Experimental Studies ◽  
Environmental Friendliness ◽  
Low Concentrations ◽  
High Concentrations ◽  
Comprehensive Study

The article is devoted to a comprehensive study of the assessment of biodegradability of polymer based on acrylic acid and its copolymers, used as an impregnation of paper napkins, by microorganisms of soil and activated sludge biocenosis. Experimental studies were carried out with 10%, 1%, 0.1%, 0.01%, 0.001% and 0.0001% aqueous solutions of polymer based on acrylic acid. The assessment of the biodegradation ability of polyacrylates by microorganisms of soil biocenosis and activated sludge was carried out on the basis of changes in the respiratory activity of microbiocenoses under conditions of introduction into the soil and waste water, respectively, of the analyzed polymer samples based on acrylic acid and its derivatives. Based on the changes in the respiratory activity of microorganisms in the presence of polymers, it was revealed that polyacrylates are biodegradable and can be used by soil microbiocenosis and activated sludge microbiocenosis as a substrate. The results of quantitative counting of microorganisms of activated sludge by the method of limiting dilutions in the process of long-term cultivation in the presence of polymer samples correlate with the results of determining the respiratory activity of microbiocenoses and indicate the possibility of using polyacrylates by microorganisms as a substrate. In the process of experimental studies, it was proved that in the aquatic environment both large respiratory activity of microorganisms at low concentrations of the polymer and a higher inhibitory activity of the polymer at its high concentrations than in the soil are observed. The results indicate the promise of using solutions of polyacrylates as impregnation of paper napkins, since the methods of processing and disposal of used napkins meet the requirements of environmental friendliness.

scholarly journals Vliv adaptace aktivovaného kalu na biodegradaci antibiotik a akumulaci genů resistence

Entecho ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 6-12
Author(s):  
Ivan Karpíšek ◽  
Jitka Zachová ◽  
Dana Vejmelková ◽  
Vladimír Sýkora
Keyword(s):  
Antibiotic Resistance ◽  
Activated Sludge ◽  
Resistance Genes ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Antibiotic Resistance Genes ◽  
Low Concentrations ◽  
Pcr Method

Aktivovaný kal na čistírnách odpadních vod je neustále vystavován nízkým koncentracím antimikrobiálních látek a dalších léčiv. To vyvolává otázku, jak mikroorganismy k těmto látkám na čistírně odpadních vod přistupují. Zda jsou schopny se v tomto prostředí na tyto látky adaptovat, degradovat je, případně je využít jako substrát. Nebo jestli jsou tyto látky aktivovaným kalem opomíjeny. Pro posouzení adaptace aktivovaného kalu byla využita metoda PCR pro sledování genů resistence a testy biologické rozložitelnosti. Pro testy byl využit aktivovaný kal z ČOV a kal adaptovaný v laboratorních SBR modelech při koncentracích antibiotik 500 ng∙l−1 a 500 μg∙l−1. Biologická rozložitelnost byla posuzována dle normy ČSN ISO 14593. Testované látky byly sledovány pomocí skupinového stanovení celkového anorganického uhlíku. Jako testované látky byly vybrány: benzylpenicilin, ampicilin, streptomycin, erythromycin, chloramfenikol, sulfamethoxazol a trimetoprim. Aktivovaný kal z čistírny odpadních vod neměl vyvinutou aktivitu k biodegradaci testovaných antibiotik. Je pravděpodobné, že vysoké zatížení snadno biologicky rozložitelným substrátem a krátké zdržení odpadní vody na ČOV, vede k tomu, že mikroorganismy aktivovaného kalu nejsou nuceny tyto látky aktivně utilizovat a brání se jim pouze tvorbou obranných mechanismů pomocí genů antibiotické resistence. Nízké koncentrace antibiotik v SBR modelech vytvářely selekční tlak na mikroorganismy a podněcovaly šíření genů antibiotické resistence. English Activated sludge in wastewater treatment plants is constantly exposed to low concentrations of antimicrobials and other drugs. This raises the question of how microorganisms approach to these substances in the sewage treatment plant. Whether they can adapt, degrade, or use antibiotics as a substrate in this environment or the activated sludge neglects these substances. To assess the adaptation of activated sludge, the PCR method for monitoring antibiotic resistance genes and biodegradability tests were used. These tests were carried out with activated sludge from WWTP and sludge adapted in laboratory SBR models at 500 ng∙l−1 and 500 μg∙l−1 of chosen antibiotics. Their biodegradability was assessed according to ČSN ISO 14593. The tested substances were monitored by group determination of total inorganic carbon. The chosen substances were: benzylpenicillin, ampicillin, streptomycin, erythromycin, chloramphenicol, sulfamethoxazole and trimethoprim. Activated sludge had no developed activity for biodegradation of tested antibiotics. It is likely that the high load of readily biodegradable substrate and the short retention of the wastewater at the WWTP lead to the activated sludge not being forced to actively utilize these substances and will only prevent from them by forming defence mechanisms using antibiotic resistance genes. Low concentrations of antibiotics in SBR models produced selective pressure on microorganisms and stimulated the spread of antibiotic resistance genes.

Investigation of the Processing of Biological Sediments by the Cryogenic Method

2020 ◽  
Vol 24 (10) ◽  
pp. 20-25
Author(s):  
L.I. Sokolov ◽  
A.N. Tyanin
Keyword(s):  
Activated Sludge ◽  
Specific Resistance ◽  
Sewage Treatment ◽  
Freezing Temperature ◽  
Sludge Dewatering ◽  
Sewage Treatment Plants ◽  
Yielding Capacity ◽  
Cryogenic Method

The study of the processes of intensification of sludge dewatering at sludge sites of sewage treatment plants (WWTP) is presented. The parameters that determine the water yielding capacity of the compacted and excess activated sludge have been clarified. The process of cascadecyclic freezing – thawing of biological sediments has been investigated. The degree of influence of cryogenesis on the specific resistance of the sediment filtration and its water yielding has been determined. Dependences of the resistivity of precipitation on the content of ashless substance and freezing temperature have been established.

Application of activated sludge and biofilm sequencing batch reactor technology to treat reject water from sludge dewatering systems: a comparison

2000 ◽  
Vol 41 (1) ◽  
pp. 115-122 ◽  
Author(s):  
E. Arnold ◽  
B. Böhm ◽  
P.A. Wilderer
Keyword(s):  
Activated Sludge ◽  
Sequencing Batch Reactor ◽  
Early Stage ◽  
Batch Reactor ◽  
Ph Control ◽  
Pilot Scale ◽  
Main Stream ◽  
Sludge Dewatering ◽  
Reject Water ◽  
Side Stream

Side stream reactors to treat reject water from sludge dewatering facilities may be considered to be small treatment plants embedded in large ones. Combination of main stream and side stream treatment provides a number of advantages. Of major importance is that tailored processes can be employed for the two waste streams very different in composition and concentration. Pilot scale experiments were conducted to study the applicability, and to compare the performance of two types of Sequencing Batch Reactor (SBR) systems, an activated sludge and a biofilm SBR. The reactors were operated to achieve nitrification only. Subsequently, the effluent of the reactors is fed into the anoxic zone of the main stream activated sludge plant to achieve denitrification. In general it can be stated that both, activated sludge and biofilm SBR systems are applicable for treating reject water of high ammonia loading. Nitrogen removal efficiencies of more than 90% could be obtained with both systems. If complete nitrification without denitrification is to be achieved, pH control is necessary. However, the amount of sodium hydroxide required for adjusting the pH during nitrification is significant. Foam development and accumulation caused major problems, especially during the early stage of start up. But the time proceeding, and by changing the type of polyelectrolyte used in the sludge dewatering process foam problems could be kept under control.

Performance of Sequencing Batch Reactor Activated Sludge Processes for Simultaneous Removal of Nitrogen, Phosphorus and Bod as Applied to Small Community Sewage Treatment

1986 ◽  
Vol 18 (7-8) ◽  
pp. 363-370 ◽  
Author(s):  
M. Okada ◽  
R. Sudo
Keyword(s):  
Activated Sludge ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Sewage Treatment ◽  
Phosphorus Release ◽  
Synthetic Wastewater ◽  
Simultaneous Removal ◽  
Small Community ◽  
Activated Sludge Processes ◽  
Nitrogen Phosphorus

Laboratory-scale sequencing batch reactor (SBR) activated sludge process was fed with synthetic wastewater to clarify the possibility of simultaneous removal of nitrogen, phosphorus, and organic substances by modifying operational schedule. Anoxic and/or anaerobic reactions in addition to aerobic reactions were introduced into a cycle of batch operation. Simultaneous removal of nitrogen, phosphorus and organic carbon was shown to be possible by the modified operation of SBR into which reactions without aeration (anoxic/anaerobic) were introduced during the fill period. Oxidized nitrogen remaining in the reactor at the end of the former cycle was removed by denitrification during the fill. Anaerobic conditions after the denitrification was completed enhanced phosphorus release from the sludge and the following luxury uptake during aeration removed phosphorus from water. Both extension and reduction of anoxic/anaerobic period in the beginning of a cycle damaged phosphorus removal and sludge settlability. Thus, an optimum length of period for these reactions must be chosen for successful operations. The best length of this period coincided with that of the fill within the range of this study.

Continuous village sewage treatment by vermifiltration and activated sludge process

2009 ◽  
Vol 60 (11) ◽  
pp. 3001-3010 ◽  
Author(s):  
Yin-Sheng Li ◽  
Yi-Qun Xiao ◽  
Jiang-Ping Qiu ◽  
Yi-Qi Dai ◽  
Paul Robin
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Filter Material ◽  
Activated Sludge Process ◽  
Practical Application ◽  
Short Term ◽  
Organic Input ◽  
Term Operation ◽  
One Year

Rural sewage treatment is now paid more and more attention in China. Vermifiltration technology could be one of the practical options under the review of previous studies. It showed good removal rates of contaminants on small to pilot scales for short-term tests. However, the impacts of season, temperature or other unknown factors are usually not taken into account. In this study, a larger vermifilter was designed to treat the sewage on village scale for long-term operation. Filter material composition was optimized by a half year experimentation. The treatment effects of vermifiltration were also compared with traditional activated sludge process for the same influent sewage. The results showed that the designed vermifiltration system could continuously treat the sewage produced by more than 100 inhabitants per day. COD, BOD5 and SS concentration in outflow were rather stable despite the fluctuation of hydraulic loading rate and organic input during one year test. It can also remove N and P to some extent. A suspending design of vermifilter bed cause adequate oxygen content in outflow of vermifilter. The comparative test showed that the treatment efficacy of vermifiltration was similar as activated sludge process. Generally, this vermifiltration system has practical application value for village sewage treatment.

scholarly journals Vliv adaptace aktivovaného kalu na biodegradaci antibiotik a akumulaci genů resistence

Entecho ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 6-12
Author(s):  
Ivan Kapríšek ◽  
Jitka Zachová ◽  
Dana Vejmelková ◽  
Vladimír Sýkora
Keyword(s):  
Antibiotic Resistance ◽  
Activated Sludge ◽  
Resistance Genes ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Antibiotic Resistance Genes ◽  
Low Concentrations ◽  
Pcr Method

Aktivovaný kal na čistírnách odpadních vod je neustále vystavován nízkým koncentracím antimikrobiálních látek a dalších léčiv. To vyvolává otázku, jak mikroorganismy k těmto látkám na čistírně odpadních vod přistupují. Zda jsou schopny se v tomto prostředí na tyto látky adaptovat, degradovat je, případně je využít jako substrát. Nebo jestli jsou tyto látky aktivovaným kalem opomíjeny. Pro posouzení adaptace aktivovaného kalu byla využita metoda PCR pro sledování genů resistence a testy biologické rozložitelnosti. Pro testy byl využit aktivovaný kal z ČOV a kal adaptovaný v laboratorních SBR modelech při koncentracích antibiotik 500 ng∙l−1 a 500 μg∙l−1. Biologická rozložitelnost byla posuzována dle normy ČSN ISO 14593. Testované látky byly sledovány pomocí skupinového stanovení celkového anorganického uhlíku. Jako testované látky byly vybrány: benzylpenicilin, ampicilin, streptomycin, erythromycin, chloramfenikol, sulfamethoxazol a trimetoprim. Aktivovaný kal z čistírny odpadních vod neměl vyvinutou aktivitu k biodegradaci testovaných antibiotik. Je pravděpodobné, že vysoké zatížení snadno biologicky rozložitelným substrátem a krátké zdržení odpadní vody na ČOV, vede k tomu, že mikroorganismy aktivovaného kalu nejsou nuceny tyto látky aktivně utilizovat a brání se jim pouze tvorbou obranných mechanismů pomocí genů antibiotické resistence. Nízké koncentrace antibiotik v SBR modelech vytvářely selekční tlak na mikroorganismy a podněcovaly šíření genů antibiotické resistence. English Activated sludge in wastewater treatment plants is constantly exposed to low concentrations of antimicrobials and other drugs. This raises the question of how microorganisms approach to these substances in the sewage treatment plant. Whether they can adapt, degrade, or use antibiotics as a substrate in this environment or the activated sludge neglects these substances. To assess the adaptation of activated sludge, the PCR method for monitoring antibiotic resistance genes and biodegradability tests were used. These tests were carried out with activated sludge from WWTP and sludge adapted in laboratory SBR models at 500 ng∙l−1 and 500 μg∙l−1 of chosen antibiotics. Their biodegradability was assessed according to ČSN ISO 14593. The tested substances were monitored by group determination of total inorganic carbon. The chosen substances were: benzylpenicillin, ampicillin, streptomycin, erythromycin, chloramphenicol, sulfamethoxazole and trimethoprim. Activated sludge had no developed activity for biodegradation of tested antibiotics. It is likely that the high load of readily biodegradable substrate and the short retention of the wastewater at the WWTP lead to the activated sludge not being forced to actively utilize these substances and will only prevent from them by forming defence mechanisms using antibiotic resistance genes. Low concentrations of antibiotics in SBR models produced selective pressure on microorganisms and stimulated the spread of antibiotic resistance genes.

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