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 w...

Hydrodeoxygenation of vegetable oil in batch reactor:Experimental considerations

The generation of reliable experimental data in any experimental scale requires proper procedures not only for the reaction step but also for the feed preparation,separation,and characterization of products as well as calculations of conversion and product yields.Batch reactor is the most used experimental setup for carrying out exploratory studies for catalyst screening and development.This work is focused on describing and discussing a step-by-step methodology for conducting experiments for catalytic hydrotreating of vegetable oils in batch reactor.The proposed methodology considers literature and own experiences on advantages and disadvantages of different feed types,catalysts,experimental setup and procedures,effect of reaction parameters,separation and characterization of products,and calculations.

A Control Algorithm for the Optimization of Batch Reactor-Based Processes

Levenberg-Marquardt(LM)algorithm is applied for the optimization of the heat transfer of a batch reactor.The validity of the approach is verified through comparison with experimental results.It is found that the mathematical model can properly describe the heat transfer relationships characterizing the considered system,with the error being kept within±2℃.Indeed,the difference between the actual measured values and the model calculated value curve is within±1.5℃,which is in agreement with the model assumptions and demonstrates the reliability and effectiveness of the algorithm applied to the batch reactor heat transfer model.Therefore,the present work provides a theoretical reference for the conversion of practical problems in the field of chemical production into mathematical models.

Performance of Sequencing Biofilm Batch Reactor(SBBR) under Micro-aerobic Condition for Aniline-Contaminated Wastewater Treatment

The performance of sequencing biofilm batch reactor( SBBR) under micro-aerobic condition for aniline-contaminated wastewater treatment was investigated in this study. Dissolved oxygen( DO) and aniline concentrations were selected as the operating variables to analyze,model,and optimize the process. In order to analyze the process,5 dependent parameters,chemical oxygen demand( COD),aniline,ammonium,total nitrogen( TN),and total phosphorous( TP) removal as the process responses were studied. From the results, increase in DO concentration could promote the removal of COD,aniline,ammonium,and TN,while increase in aniline concentration has a slightly negative impact on the removal of pollutants. The optimum DO concentration was found to be 0. 4-0. 5 mg /L. The removal efficiencies for COD,aniline,ammonium,and TN at the optimum point( DO concentration0. 5 mg /L,aniline concentration 11 mg /L) were 95. 84%,100%,75. 72%,and 45. 39%,respectively. The oxidative deamination was the main degradation method for aniline under micro-aerobic condition. Simultaneously nitrification-denitrification( SND)process performed under micro-aerobic condition and about 20%-40% nitrogen was removed by SND.

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.

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 fulvic-like substances are also associated with the disintegration of the aerobic granules.

Nitrous Oxide Production in a Sequence Batch Reactor Wastewater Treatment System Using Synthetic Wastewater

The rate of nitrous oxide emission from a laboratory sequence batch reactor (SBR) wastewater treatment system using synthetic wastewater was measured under controlled conditions. The SBR was operated in the mode of 4 h for aeration, 3.5 h for stirring without aeration, 0.5 h for settling and drainage, and 4 h of idle. The sludge was acclimated by running the system to achieve a stable running state as indicated by rhythmic changes of total N, dissolved oxygen, chemical oxygen demand, NO^-_2, NO^-_3, NH^+_4, pH, and N2O. Under the present experimental conditions measured nitrous oxide emitted from the off-gas in the aerobic and anaerobic phases, respectively, accounted for 8.6%-16.1% and 0-0.05% of N removed, indicating that the aerobic phase was the main source of N2O emission from the system. N2O dissolved in discharged water was considerable in term of concentration. Thus, measures to be developed for the purpose of reducing N2O emission from the system should be effective in the aeration phase.

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(λ<794.87 nm).And characterization also shows that there are alkyl groups on its surface.It takes 40 min to improve the biodegradability of dyestuff wastewater.Five-day biochemical oxygen demand(BOD5) 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.

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 c orrelation between ammonia nitrogen(NH3-N) and p-toluidine using sequencing batc h 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 temperatur e varied from 10 to 25℃, respectively. The results showed that the concentratio n of NH3-N turned from increase to decrease when p-toluidine was nearly complete ly 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 su crose in the influent, aerated airflow and temperature. It is showed that using ammonia nitrogen as monitoring and control parameter is feasible and reliable an d has promising application in amine wastewater treatment by SBR.

2D multi-model general predictive iterative learning control for semi-batch reactor with multiple reactions

Batch to batch temperature control of a semi-batch chemical reactor with heating/cooling system was discussed in this study. Without extensive modeling investigations, a two-dimensional(2D) general predictive iterative learning control(2D-MGPILC) strategy based on the multi-model with time-varying weights was introduced for optimizing the tracking performance of desired temperature profile. This strategy was modeled based on an iterative learning control(ILC) algorithm for a 2D system and designed in the generalized predictive control(GPC) framework. Firstly, a multi-model structure with time-varying weights was developed to describe the complex operation of a general semi-batch reactor. Secondly, the 2 D-MGPILC algorithm was proposed to optimize simultaneously the dynamic performance along the time and batch axes. Finally, simulation for the controller design of a semi-batch reactor with multiple reactions was involved to demonstrate that the satisfactory performance could be achieved despite of the repetitive or non-repetitive disturbances.

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.

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.

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 H_2 content(around 37%)related to the total biogas production rate for the ASBR System running at p H 5.0.When the H_2 content went beyond 37%,an appreciable decline in biogas production rate was observed,implying that there might exist an H_2 content limit in the biogas.For other HRTs(8 through 20 h),an average H_2 content of 42%could be achieved.In the second experiment(HRT 12 h),the highest H_2 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 H_2 content than the downswing of p H from5.0 to 4.3.The results also indicated good linear relationships of biogas and H_2 production rates with HRT(r=0.9971 and0.9967,respectively).Since the optimal ASBR operating conditions were different for the biogas/H_2 production rates and the H_2 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/H_2 productions.

Treatment of Practical Dye Wastewater Using a Double Dielectric Barrier Discharge System Combined with a Sequencing Batch Reactor System

Synthetic dyes are substances that are relatively stable and difficult to degrade in wastewater treatment plants using normal physical,chemical or / and biological treatment. The present work explored the synergistic effect of non-thermal plasma( NTP) and biological wastewater treatment technologies on practical dye wastewater degradation by establishing a double dielectric barrier discharge( DDBD) system combined with a sequencing batch reactor( SBR) system. The biodegradation and degradation efficiency of the DDBD-SBR system was investigated. The investigation results indicated that the DDBD technology was effective in treating the practical dye wastewater as a pre-treatment process. After a 10-min treatment,although the total organic carbon( TOC) removal efficiency was not so significant, the decolouration and the biodegradation were improved greatly. The microbial toxicity test revealed that the sample after degradation became less toxic than the original dye,which demonstrated the treatment had a significant effect on the reduction of toxicity. In addition,the SBR technology remedied the defects of DDBD treatment and improved TOC removal efficiency noticeably. The hybrid DDBD-SBR system made full use of the advantages of the individual technologies and exhibited an efficient capability for practical dye wastewater treatment.

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.

Developing a Mathematical Model for Hydrate Formation in a Spray Batch Reactor

The formation of methane hydrate was undertaken in this research. The purpose of this work was to model the methane hydrate formation with a hydrate-water–methane system in a semi-batch reactor under steady–state, isothermal and isobaric conditions. Obtained results were validated with experiments conducted in a semi-batch spray reactor at low temperatures and high pressures. The investigated formation of gas hydrate from pure methane required physical constants of these materials which were determined through experimental data. The experiments hence, the theoretical calculations were conducted with pure methane and carried out in a spray reactor at 273.95K and 8705kPa to determine the actual amount of hydrate formation in such reactor. Ultimately;the comparison of the results generated from the developed mathematical model with those of experimental data of others indicated a very satisfactory agreement obtained.

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 conventionalSBR.The set up of 4-or 8-hour anaerobic mixing period in a SBR’s cycle did not benefit for PVAdegradation.While an anaerobic reactor seeded with anaerobic sludge could partly hydrolyse andacidify 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 liquorfrom 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 andanaerobic 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.

Transformation and performance of granular sequence batch reactor under conventional organic loading rate condition

Laboratory experiments were conducted to investigate the transformation and performance of a granular sequence batch reactor(SBR) under the conventional organic loading rate(OLR) condition.Aerobic granules were successfully cultivated in a SBR by means of alternative feeding load combined with reducing settling time after 60 d operational period.Subsequently,the black fungal granules were presented in reactor because of the filamentous overgrowth on the surface of aerobic granules.A small amount of fungal granules had no effect on the performance of granular SBR.Aerobic granules completely vanished and fungal granules eventually became the dominant species in subsequent 90 d operation after granulation.The three-dimensional excitation emission matrix(EEM) spectra result shows that the extracellular polymeric substances(EPS) component in both granules has no much difference,whereas the content of EPS in fungal granules is higher than that in bacterial granules.Due to their low bioactivity,the chemical oxidation demand(COD) and NH4-N removal efficiencies gradually decrease from 90.4%–96.5% and 99.5% to 71.8% and 32.9% respectively while the fungal granules become dominant in the 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.