Effect of inorganic carbon on anaerobic ammonium oxidation enriched in sequencing batch reactor

The present lab-scale research reveals the enrichment of anaerobic ammonium oxidation microorganism from methanogenic anaerobic granular sludge and the effect of inorganic carbon(sodium bicarbonate)on anaerobic ammonium oxidation.The enrichment of anammox bacteria was carried out in a 7.0-L sequencing batch reactor(SBR)and the effect of bicarbonate on anammox was conducted in a 3.0-L SBR.Research results,especially the biomass,showed first signs of anammox activity after 54 d cultivation with synthetic wast...

Characteristics of extracellular fluorescent substances of aerobic granular sludge in pilot-scale sequencing batch reactor

The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor （SBR）, and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances （EPS） of sludge samples were extracted and analyzed during the granulation and storage process. The results show that the contents of protein and EPS increase along with the granulation process, while polysaccharides remain almost unchanged. The content of protein in EPS is almost two-fold larger than that of polysaccharides in granular sludge cultivated with municipal wastewater. Moreover, some of the granules disintegrate during storage, corresponding to the decrease of protein contents in EPS. Three peaks are identified in three-dimensional excitation emission matrix （EEM） fluorescence spectra of the EPS in the aerobic granules. Two peaks （A and B） are attributed to the protein-like fluorophores, and the third （peak C） is related to visible fulvic-like substances. Peak A gradually disappears during storage, while a new peak related to ultraviolet fulvic acid （peak D） is formed. The formation and the stability of aerobic granules are closely dependent on the quantity and composition of EPS proteins. Peak C has no obvious changes during granulation, while the fulvic-like substances present an increase in fluorescence intensities during storage, accompanied with an increase in structural complexity. The fulvie-like substances are also associated with the disintegration of the aerobic granules.

Pretreatment of coking wastewater using anaerobic sequencing batch reactor (ASBR)

A laboratory-scale anaerobic sequencing batch reactor (ASBR) was used to pretreat coking wastewater. Inoculated anaerobic granular biomass was acclimated for 225 d to the coking wastewater, and then the biochemical methane potential (BMP)of the coking wastewater in the acclimated granular biomass was measured. At the same time, some fundamental technological factors, such as the filling time and the reacting time ratio (tf/tr), the mixing intensity and the intermittent mixing mode, that affect anaerobic pretreatment of coking wastewater with ASBR, were evaluated through orthogonal tests. The COD removal efficiency reached 38％～50％ in the stable operation period with the organic loading rate of 0.37～0.54 kg COD/(m3.d) at the optimum conditions of tf/tr, the mixing intensity and the intermittent mixing mode. In addition, the biodegradability of coking wastewater distinctly increased after the pretreatment using ASBR. At the end of the experiment, the microorganism forms on the granulated sludge in the ASBR were observed using SEM (scanning electron microscope) and fluoroscope. The results showed that the dominant microorganism on the granular sludge was Methanosaeta instead of Methanosarcina dominated on the inoculated sludge.

Effect of Sludge Retention Time on Nitrite Accumulation in Real-time Control Biological Nitrogen Removal Sequencing Batch Reactor

In this study,four sequencing batch reactors(SBR),with the sludge retention time(SRT)of 5,10,20 and 40 d,were used to treat domestic wastewater,and the effect of SRT on nitrite accumulation in the biological nitrogen removal SBR was investigated.The real-time control strategy based on online parameters,such as pH,dissolved oxygen(DO)and oxidation reduction potential(ORP),was used to regulate the nitrite accumulation in SBR. The model-based simulation and experimental results showed that with the increase of SRT,longer time was needed to achieve high level of nitritation.In addition,the nitrite accumulation rate(NAR)was higher when the SRT was relatively shorter during a 112-day operation.When the SRT was 5 d,the system was unstable with the mixed liquor suspended solids(MLSS)decreased day after day.When the SRT was 40 d,the nitrification process was significantly inhibited.SRT of 10 to 20 d was more suitable in this study.The real-time control strategy combined with SRT control in SBR is an effective method for biological nitrogen removal via nitrite from wastewater.

On-line Monitoring for Phosphorus Removal Process and Bacterial Community in Sequencing Batch Reactor

For efficient energy consumption and control of effluent quality, the cycle duration for a sequencing batch reactor (SBR) needs to be adjusted by real-time control according to the characteristics and loading of waste-water. In this study, an on-line information system for phosphorus removal processes was established. Based on the analysis for four systems with different ecological community structures and two operation modes, anaerobic-aerobic process and anaerobic-anaerobic process, the characteristic patterns of oxidation-reduction potential (ORP) and pH were related to phosphorous dynamics in the anaerobic, anoxic and aerobic phases, for determination of the end of phosphorous removal. In the operation mode of anaerobic-aerobic process, the pH profile in the anaerobic phase was used to estimate the relative amount of phosphorous accumulating organisms (PAOs) and glycogen accumulat-ing organisms (GAOs), which is beneficial to early detection of ecology community shifts. The on-line sensor val-ues of pH and ORP may be used as the parameters to adjust the duration for phosphorous removal and community shifts to cope with influent variations and maintain appropriate operation conditions.

Evaluation of the correlation between ammonia nitrogen and p-toluidine using sequencing batch reactor treating synthetic p-toluidine wastewater

This paper presents lab-scale experiment carried out to evaluate the correlation between ammonia nitrogen （NH3-N） and p-toluidine using sequencing batch reactor treating synthetic p-toluidine wastewater. The profiles of NH3-N and p-toluidine were traced under the concentration of sucrose in the influent varied from 0 to 500 mg/L, aerated airflow varied from 0.6 to 1.2 L/min and temperature varied from 10 to 25℃, respectively. The results showed that the concentration of NH3-N turned from increase to decrease when p-toluidine was nearly completely biodegraded, so the profile of NH3-N could clearly indicate the endpoint of p-toluidine biodegradation. And the profile of NH3-N was not influenced by the sucrose in the influent, aerated airflow and temperature. It is showed that using ammonia nitrogen as monitoring and control parameter is feasible and reliable and has promising application in amine wastewater treatment by SBR.

Dyestuff wastewater treatment by combined SDS-CuO/TiO_2 photocatalysis and sequencing batch reactor

Combined technology of SDS-CuO/TiO2 photocatalysis and sequencing batch reactor （SBR） were applied to treating dyestuff wastewater. Photocatalysis was carried out in a spiral up-flow type reactor as pre-treatment. SDS-CuO/TiO2 photocatalyst was prepared by modification of nano-TiO2 using CuO and sodium dodecyl sulfate （SDS）. Results show that the SDS-CuO/TiO2 photocatalyst contains two kinds of crystals, including TiO2 and CuO. The band gap of this photocatalyst is 1.56 eV, indicating that it can be excited by visible light （2〈794.87 nm）. And characterization also shows that there are alkyl groups on its surface. It takes 40 rain to improve the biodegradability of dyestuff wastewater. Five-day biochemical oxygen demand （BODs） and dehydrogenase activity （DHA） of wastewater reach the maximum value when dissolved oxygen is higher than 2.97 mg/L. SBR reactor was used to treat this biodegradability improved wastewater. Chemical oxygen demand （COD） and colority decline to 72 mg/L and 20 times, respectively, when the sludge loading is 0.179 kg（COD）/[kg（MLSS）＇d], dissolved oxygen is 4.09 mg/L and aeration time is 10 h.

Combined treatment of landfill leachate with fecal supernatant in sequencing batch reactor

A laboratory-scale sequencing batch reactor (SBR) is used to treat landfill leachate containing high concentration of ammonium nitrogen with municipal fecal supernatant. The SBR system is operated in the following sequential phases: fill period, anoxic period, aeration period, settling period, decant and idle period. The results indicated that the average removal efficiencies of COD, BOD5, TN, NH 4+-N were 93.76%, 98.28%, 84.74% and 99.21%, respectively. The average sludge removal loading rates of COD, BOD5, TN and NH 4+-N were 0.24 kg/(kg SS?d), 0.08 kg/(kg SS?d), 0.04 kg/(kg SS?d) and 0.036 kg/(kg SS?d), respectively. Highly effective simultaneous nitrification and denitrification was achieved in the SBR system. The ratio of nitrification and denitrification was 99% and 84%, respectively. There was partial NO?2 denitrification in the system.

In-depth observations of fermentative hydrogen production from liquid swine manure using an anaerobic sequencing batch reactor

In this study,experiments were designed to reveal in-depth information of the effect of pH and hydraulic retention time（HRT）on biohydrogen fermentation from liquid swine manure supplemented with glucose using an Anaerobic Sequencing Batch Reactor（ASBR）System.Five values of HRT（8,12,16,20,and 24 h）were first tested and the best HRT determined was further studied at five p H levels（4.4,4.7,5.0,5.3,and 5.6）.The results showed that for HRT 24 h,there was a dividing H2 content（around 37%）related to the total biogas production rate for the ASBR System running at p H 5.0.When the H2 content went beyond 37%,an appreciable decline in biogas production rate was observed,implying that there might exist an H2 content limit in the biogas.For other HRTs（8 through 20 h）,an average H2 content of 42%could be achieved.In the second experiment（HRT 12 h）,the highest H2 content（35%）in the biogas was found to be associated with p H 5.0.The upswing of p H from 5.0 to 5.6 had a significantly more impact on biogas H2 content than the downswing of p H from5.0 to 4.3.The results also indicated good linear relationships of biogas and H2 production rates with HRT（r=0.9971 and0.9967,respectively）.Since the optimal ASBR operating conditions were different for the biogas/H2 production rates and the H2 yield,a compromised combination of the running parameters was determined to be HRT 12 h and pH 5.0 in order to achieve good biogas/H2 productions.

Simultaneous Nitrogen and Phosphorus Removal by Denitrifying Dephosphatation in a (AO)_2 Sequencing Batch Reactor

A 24 L working volume reactor was used for the research on simultaneous phosphorus (P) and nitrogen (N) removal by denitrifying dephosphatation in an anaerobic-oxid-anoxic-oxid sequencing batch reactor ((AO)_2SBR) system. The durations of each phase are: anaerobic 1.5 h, aerobic 2.5 h, anoxic 1.5 h, post-aerobic 0.5 h, settling 1.0 h, fill 0.5 h. The successful removal of nitrogen and phosphorus is achieved in a stable (AO)_2SBR. The effluent P concentrations is below 1 mg/L, and the COD,TN and P average removal efficiency is 88.9%, 77.5% and 88.7%, respectively. The batch experiment results show that the durations of aerobic and anoxic phase influence the P removal efficiency. Some feature points are found on the DO, ORP and pH curves to demonstrate the complete of phosphate release and phosphate uptake. These feature points can be used for the control of (AO)_2 SBR.

Function of anaerobic portion in a conventional sequencing batch reactor

The performance of SBRs treating two kinds of wastewater(synthetic wastewater con- taining polyvinyl alcohol and effluent from a coke-plant wastewater treatment system)was investi- gated in this study,in order to examine the exact function of anaerobic portion in a conventional SBR.The set up of 4-or 8-hour anaerobic mixing period in a SBR's cycle did not benefit for PVA degradation.While an anaerobic reactor seeded with anaerobic sludge could partly hydrolyse and acidify PVA into readily-degradable intermediates.During the anaerobic fill period of an SBR treat- ing the effluent from a coke-plant wastewater treatment system,the organic concentration was re- duced to certain extent due to the adsorption of activated sludge and dilution of the mixed liquor from the previous cycle.Parts of readily-degradable organics in the influent were utilised by denitri- fiers as carbon source.The biomass in a conventional SBR was alternatively imposed to aerobic and anaerobic conditions in its operating cycle,the environmental conditions needed for anaerobic hy- drolization and acidification of refractory organics could not occur in such an SBR.

Factors affecting biological denitrifying dephosphatation in anaerobic/anoxic/aerobic sequencing batch reactor

This study was conducted to verify and discuss the denitrifying dephosphatation under different levels of nitrate concentration and retention time of anoxic/aerobic process in a Sequencing Batch Reactor (SBR). The results of tests demonstrated that there were two kinds of phosphorus-accumulating organisms (PAOs) in the biological excess phosphorus removal (BEPR) system. One was non-DNPAOs that could only use oxygen as terminal electron acceptors, the other was denitrifying PAOs (DNPAOs) that could use both nitrate and oxygen as terminal electron acceptors. Phosphorus uptake efficiency could be attained under anoxic period ranging from 28.7%-96.7% in an anaerobic/anoxic/aerobic system. Experimental results showed that nitrate concentration and retention time of anoxic/aerobic process were the key factors affecting the course of denitrifying dephosphatation.

Characterization of the start-up period of single-step autotrophic nitrogen removal in a sequencing batch reactor

The characteristics of the start-up period of single-step autotrophic nitrogen removal process were investigated. The autotrophic nitrogen removal process used a sequencing batch reactor to treat wastewater of medium to low ammonia-nitrogen concentration, with dissolved oxygen （DO）, hydraulic retention time （HRT） and temperature controlled. The experimental conditions were temperature at （30±2） ℃, ammonia concentration of （60 to 120） mg/L, DO of （0.8 to 1.0） mg/L, pH from 7.8 to 8.5 and HRT of 24 h. The rates of nitrification and nitrogen removal turn out to be 77% and 40%, respectively, after a start up period going through three stages divided according to nitrite accumulation： sludge domestication, nitrifying bacteria selection and sludge adaptation, It is demonstrated that dissolved oxygen is critical to nitrite accumulation and elastic YJZH soft compound packing is superior to polyhedral hollow balls in helping the bacteria adhere to the membrane.

Combined process of sequencing batch reactor activated sludge process and constructed wetland for domestic wastewater treatment

By combining sequencing batch reactor (SBR) activated sludge process and constructed wetland (CW), this study is to achieve the domestic wastewater treatment. Our purpose was to determine the optimum operating parameters of the combined process. The process involved advantages and shortages of SBR and CW. Under normal temperature, the 3rd cycle (SBR’s operation cycle is 8 h: inflow for 1 h, limited aeration for 3 h, sediment for 1 h, outflow for 1 h, and idling for 2 h; CW’s hydraulic retention time (HRT) is 24.8 h and hydraulic loading is 24.5 m3/m2 d) was the best cyclic mode. The effluents can meet the standard GB/T18921-2002: "The reuse of urban recycling water: water quality standard for scenic environment use". In the 3rd cycle, the efficiency of CW was the maximum, and energy consumption of SBR was the minimum. Under the condition of low dissolved oxygen, the removing efficiency of chemical oxygen demand (COD) and ammonia was not affected obviously. Simultaneously, nitrification and denitrification phenomena occured and phosphorus was absorbed obviously.

Removal of Pharmaceutically Active Compounds in Sequencing Batch Reactor

Biological treatment efficiency of six pharmaceutical compounds （acetazolamide, metronidazole, opipramol, piracetam, salicylamide and tinidazole） was evaluated using lab-scale Sequencing Batch Reactor （SBR）. Comparative biological degradation processes of two types of activated sludge from municipal and pharmaceutical industry sewage treatment plants were examined. Three different organic loadings （0.05 g COD/g MLSS.d, 0.1 g COD/g MLSS.d and 0.2 g COD/g MLSS-d） and reaction time on the efficiency of Active Pharmaceutical Ingredient （API） decomposition were examined. Chemical oxygen demand, non-purgeable organic carbon as well as ammonium nitrogen contents were monitored by standard methods. Percentage of API decomposition was analysed by High Performance Liquid Chromatography （HPLC）. The overall API removal efficiency was strictly dependent on the type of activated sludge origin. The main biodegradation products were identified using HPLC-MS,1H NMR and 13C NMR methods as e.g. （{4-[3-（5H-dibenzo[b,f]azepin-5-yl]piperazin-l-yl}methanamine） and （2-amino-1,3,4-thiadiazol-5-sulfonamide） for opipramol and acetazolamide respectively.

Production of Poly-b-hydroxybutyrate by Activated Sludge in Sequencing Batch Reactor under Aerobic Conditions

In order to improve poly-β-hydroxybutyrate（PHB） production in activated sludge, the anaerobic/aerobic alternative operating sequencing batch reactor（SBR） process was applied in this paper to accumulate PHB. Effects of nutritional conditions and carbon concentration on PHB accumulation were studied. Results indicated that PHB accumulation reached the highest level and accounted for 11.2 % under anaerobic condition for phosphate limitation and 20.84 % under aerobic condition for nitrogen and phosphate limitation of mixed liquor suspended solid（MLSS）, respectively. In addition, 4 g/L was proved to be the optimum carbon concentration in both anaerobic and aerobic experiments, and the PHB accumulation reached 17.1 %（anaerobic, phosphorus limitation） and 60.4 %（aerobic, nitrogen and phosphorus limitation） of MLSS, respectively. PHB could be successfully extracted with sodium hypochlorite and chloroform method from the activated sludge. In addition, the infrared spectrum showed that the PHB sample extracted was of high purity.

Effect of operational parameters on the performance of an anaerobic sequencing batch reactor(AnSBR)treating protein-rich wastewater

Treating protein-rich wastewater using cost-effective and simple-structured single-stage reactors presents several challenges.In this study,we applied an anaerobic sequencing batch reactor(AnSBR)to treat protein-rich wastewater from a slaughterhouse.We focused on identifying the key factors influencing the removal of chemical oxygen demand(COD)and the settling performance of the sludge.The AnSBR achieved a maximum total COD removal of 90%,a protein degradation efficiency exceeding 80%,and a COD to methane conversion efficiency of over 70%at organic loading rates of up to 6.2 g COD L^(-1)d^(-1).We found that the variations in both the organic loading rate within the reactor and the hydraulic retention time in the buffer tank had a significant effect on COD removal.The hydraulic retention time in the buffer tank and the reactor,which determined the ammonification efficiencies and the residual carbohydrate concentrations in the reactor liquid,affected the sludge settleability.Furthermore,the genus Clostridium sensu stricto 1,known as protein-and lipids-degraders,was predominant in the reactor.Statistical analysis showed a significant correlation between the core microbiome and ammonification efficiency,highlighting the importance of protein degradation as the governing process in the treatment.Our results will provide valuable insights to optimise the design and operation of AnSBR for efficient treatment of protein-rich wastewater.

Effect of high-strength ammonia nitrogen acclimation on sludge activity in sequencing batch reactor

The effect of high-strength ammonia nitrogen acclimation on sludge activity in sequencing batch reactor （SBR） was investigated. Two batch experiments, RUN1 and RUN2, were conducted with the influent ammonia nitrogen concentrations 60 and 500 mg/L, respectively. The sludges inoculated from RUN1 and RUN2 were used to treat a series of influent with ammonia nitrogen concentrations of 59, 232, 368, 604 and 1152 mg/L. It is found that the activated sludge acclimated to higher ammonia nitrogen concentrations revealed higher COD and NH 4 ＋ -N removal efficiencies, and slower DHA decrease. The results confirmed that the activities of the bacteria in activated sludge in SBR were inhibited by high-strength ammonia nitrogen, whereas the activated sludge acclimated to high-strength ammonia nitrogen showed substantial resistance to inhibition by influents containing high levels of ammonia nitrogen.

Simultaneous biodegradation of nitrogen-containing aromatic compounds in a sequencing batch bioreactor

Many nitrogen-containing aromatic compounds （NACs）, such as nitrobenzene （NB）, 4-nitrophenol （4-NP）, aniline （AN）, and 2,4-dinitrophenol （2,4-DNP）, are environmentally hazardous, and their removal from contaminated water is one of the main challenges facing wastewater treatment plants. In this study, synthetic wastewater containing NB, 4-NP, 2,4-DNP, and AN at concentrations ranging from 50 to 180 mg/L was fed into a sequencing batch reactor （SBR）. Analyses of the SBR system indicated that it simultaneously removed more than 99% of the NACs at loading rates of 0.36 kg NB/（m^3·d）, 0.3 kg 4-NP/（m^3·d）, 0.25 kg AN/（m^3·d）, and 0.1 kg 2,4-DNP/（m^3·d）. Bacterial groups of Bacteriodetes, Candidate division TM7, α-Proteobacteria, and β-Proteobacteria were dominant in the clone libraries of 16S rRNA genes retrieved from the microbial communities in the SBR system. ＂Cycle tests＂ designed to alter feeding and aeration parameters of the SBR system demonstrated that the resident microbial biome of the SBR system responded rapidly to changing conditions. Consumption of O2 was concomitant with the apparent mineralization of NACs. Aromatic ring-cleaving dioxygenase activities suggested that （1） AN and NB were degraded via catechol 2,3-dioxygenase; （2） 4-NP was degraded via 1,2,4-benzentriol 1,2-dioxygenase; and （3） 2,4-DNP was degraded via an unresolved pathway.