厌氧序批式反应器(ASBR)处理啤酒废水的试验研究

考察了ASBR工艺对啤酒废水CODCr去除率和产气率的影响。研究表明,ASBR处理啤酒废水适宜参数为:温度30~40℃,pH7~8,反应时间24h,MLSS5000~5500mg/L。在此工艺参数下连续运行1周,CODCr、TSS去除率分别为80.9%、74%,产气率约为500L/kgCODCr。     

Application of sequencing batch membrane bioreactors (SB-MBR) for the treatment of municipal wastewater

Sequencing batch membrane bioreactors can be a good option in up-grading small municipal plant and for industrial applications, maintaining some of the advantages of both original technologies (effluent quality improvement, flexibility and simplicity of realization, operation and control). In this study, the effects of volumetric exchange ratio (VER) and aeration/filtration strategy have been evaluated. Moreover, with the adoption of cycles shorter than 8 h, the opportunity of further simplification of the membrane operation has been tested by choosing a continuous filtration mode instead of the usual short cycle of permeation/relaxation. Two lab-scales MBR equipped with Zenon hollow fiber modules were fed on real primary effluent. For all tests, hydraulic retention time of 10 h and sludge retention time of 60 days have been adopted. Different cycles have been investigated, lasting between 1 and 8 h and all comprising an anoxic phase to allow for denitrification. Operation at low VER resulted in better effluent quality with no limitations to the denitrification phase. For VER >33% a pre-aeration step was required before effluent withdrawal for optimal ammonium removal. Moreover, VER appeared to have limited negative effect on sludge concentration and yield, while the membrane cleaning frequency slightly increased for increasing VER.     

Iron-mediated removal of ammonium from strong nitrogenous wastewater from food processing.

The combination of microbial reduction and further microbial oxidation of iron was applied to the treatment of food-processing wastewater and recovery of ammonium. Fe2+ ions were formed by iron-reducing bacteria under anaerobic conditions. Ammonium was recovered by co-precipitation with negatively charged iron hydroxides produced during oxidation of Fe2+ by iron-oxidizing bacteria under microaerophilic conditions. The value-added by-product of this process can be used as a slowly released ammonium fertilizer.     

气浮-MBBR工艺处理水产品生产废水

应用气浮-MBBR工艺处理水产品生产废水,实践证明:在进水CODCr≤2000mg/L,BOD5≤900mg/L,SS≤600mg/L的条件下,经过气浮-MBBR处理后出水水质达到《污水综合排放标准》(GB8978-1996)一级标准,出水的CODCr<100mg/L、BOD5<30mg/L和SS<50mg/L。     

食品加工废水培养复合型微生物絮凝剂产生菌及优化研究

利用食品加工废水对复合型微生物絮凝剂产生菌进行驯化培养,考察其产絮凝剂周期和优化培养条件,并且进行了废水处理试验。试验结果表明,絮凝剂产生菌X1、X16、X20以及X38在果蔬脆片浸糖废水中培养30 h后,其絮凝活性分别为87．6％、86．5％、79．7％和82．1％。将其按不同比例进行混合培养,从中筛选出絮凝率较高且稳定的混合菌株H6,其最佳培养条件:CODCr为 3 018 mg／L、氮源为硫酸铵、初始pH为6和相对接种量为10 ％,在该条件下絮凝活性为87．3 ％。     

Evaluation of performance and microbial ecology of sequencing batch reactor and membrane bioreactor treating thin-film transistor liquid crystal display wastewater

In Taiwan, a substantial amount of thin-film transistor liquid crystal display (TFT-LCD) wastewater is produced daily due to an increasing production of the opto-electronic industry in recent years. The main components of TFT-LCD wastewater include dimethyl sulphoxide (DMSO), monoethanolamine (MEA), and tetra-methyl ammonium hydroxide (TMAH), which are recognized as non-or slow-biodegradable organic compounds and limited information is available regarding their biological treatablility. This study was conducted to evaluate the long-term performance of two bioreactors, anaerobic-aerobic (A/O) sequencing batch reactor (SBR) and aerobic membrane bioreactor (MBR), treating synthetic TFT-LCD wastewater containing DMSO, MEA, and TMAH with different loadings. For the A/O SBR, the influent wastewater was composed of 800 mg MEA/L, 430 mg DMSO/L, and 90 mg TMAH/L, respectively. After reaching steady-state, SBR was able to achieve more than 99% degradation efficiencies for the three compounds examined. For the case of aerobic MBR, the influent wastewater was composed of 550 mg MEA/L, 270 mg DMSO/L, and 330 mg TMAH/L, respectively, and degradation efficiencies for the three compounds achieved more than 99%. Although both different reactors shared similar and satisfactory degradation efficiencies for DMSO, MEA, and TMAH, the microbial ecology of these two reactors, as elucidated with molecular methods, was apparently different. The 16S rDNA-based cloning/sequencing results indicated that the dominant sequences retrieved from the aerobic MBR, including Hyphomicrobium denitrificans, Hyphomicrobium zavarzinii, Rhodobacter sp., and Methyloversatilis universalis, showed a clear linkage to their physiological properties of DMSO and TMAH degradation. On the other hand, Zoogloea sp., Chlorobium chlorochromatii, Agricultural soil bacterium, and Flavosolibacter ginsengiterrae were proliferated in the A/O SBR Run1, while Thiobacillus sp., Nitrosomonas sp., Thauera aromatica and Azoarcus sp. became dominant in Run2. Furthermore, the sequences retrieved from different reactors were used to establish the terminal restriction fragment length polymorphism (TRFLP) fingerprint methodology for monitoring the dynamics of dominant degrading bacteria in the aerobic MBR treating TFT-LCD wastewater.     

Treatment of strong nitrogen swine wastewater in a full-scale sequencing batch reactor.

Treatment of swine wastewater containing strong nitrogen was attempted in a full-scale SBR. The strongest swine wastewater was discharged from a slurry-type barn and called swine-slurry wastewater (SSW). Slightly weaker wastewater was produced from a scraper-type barn and called swine-urine wastewater (SUW). TCOD, NH4+-N and TSS in raw SSW were 23,000-72,000 mg/L, 3,500-6,000 mg/L and 17,000-50,000 mg/L, respectively. A whole cycle of SBR consists of 4 sub-cycles with anoxic period of 1 hr and aerobic period of 3 hr. The maximum loading rates of both digested-SSW and SUW were similar to 0.22 kg NH4+-N/m3/day whereas the maximum loading rates of raw SSW was up to 0.35 TN/m3/day on keeping the effluent quality of 60 TN mg/l. The VFAs portion of SCOD in raw SSW was about more than 60%. The VFAs in SUW and digested-SSW were about 22% and 15%, respectively. NH4+-N and PO4(3-)-P in SSW were removed efficiently compared to those in digested-SSW and DUW because SSW had high a C/N ratio and readily biodegradable organic. High concentration of organic was useful to enhance denitrification and P uptake. Also the amount of external carbon for denitrification was reduced to 5% and 10% of those for digested-SSW and SUW.     

Nitrite accumulation by aeration controlled in sequencing batch reactors treating domestic wastewater.

The feasibility of obtaining and keeping stable nitrite accumulation in Sequencing Batch Reactors (SBRs) treating domestic wastewater is studied. The final product of ammonium oxidation is either reproducible nitrate or nitrite depending on the aeration strategy. With the aerobic-anoxic sequence, two SBRs fed with domestic wastewater are operated in parallel. One SBR (SBR1) is controlled by the aeration control strategy, and the other SBR (SBR2) by alternate aeration control strategy. Based on the on-line indirect measurements of DO and pH, the relationship between pH (or DO) and nitrogen concentration (NH4+-N, NO(3-)-N and NO(2-)-N) is investigated. The result indicates that pH and DO can be used as control parameters for the real-time aeration control strategy to obtain nitritation in SBR treating domestic wastewater. The result of SBR1 indicates that long-term stable nitritation is possible at 32+/-1 degrees C. The result of SBR2 indicates that the aeration control strategy is necessary for nitritation during the acclimation period, because the nitrite accumulation disappears when the aeration is extended.     

Optimal biodegradation of phenol and municipal wastewater using a controlled sequencing batch reactor.

This work presents the results of the application of an optimally controlled influent flow rate strategy to biodegrade, in a discontinuous reactor, a mixture of municipal wastewater and different concentrations of phenol when used as a toxic compound model. The influent is fed into the reactor in such a way to obtain the maximal degradation rate avoiding the inhibition of the microorganisms. Such an optimal strategy was able to manage increments of phenol concentrations in the influent up to 7000 mg/L without any problem. It was shown that the optimally controlled influent flow rate strategy is a good and reliable tool when a discontinuous reactor is applied to degrade an industrial wastewater.     

Aerobic granulation in a sequencing batch reactor (SBR) for industrial wastewater treatment.

Aerobic granulation seems to be an a attractive process for COD removal from industrial wastewater, characterised by a high content of soluble organic compounds. In order to evaluate the practical aspects of the process, comparative experimental tests are performed on synthetic and on industrial wastewater, originating from pharmaceutical industry. Two pilot plants are operated as sequencing batch bubble columns. Focus was put on the feasibility of the process for high COD removal and on its operational procedure. For both wastewaters, a rapid formation of aerobic granules is observed along with a high COD removal rate. Granule characteristics are quite similar with respect to the two types of wastewater. It seems that filamentous bacteria are part of the granule structure and that phosphorus precipitation can play an important role in granule formation. For both wastewaters similar removal performances for dissolved biodegradable COD are observed (> 95%). However, a relatively high concentration of suspended solids in the outlet deteriorates the performance with regard to total COD removal. Biomass detachment seems to play a non-negligible role in the current set-up. After a stable operational phase the variation of the pharmaceutical wastewater caused a destabilisation and loss of the granules, despite the control for balanced nutrient supply. The first results with real industrial wastewater demonstrate the feasibility of this innovative process. However, special attention has to be paid to the critical aspects such as granule stability as well as the economic competitiveness, which both will need further investigation and evaluation.     

Enrichment of activated sludge in a sequencing batch reactor for polyhydroxyalkanoate production.

The paper describes the start up of a process for the production of polyhydroxyalkanoates (PHAs) from activated sludge. The excess sludge from a wastewater treatment plant was inoculated in a lab-scale sequencing batch reactor (SBR) to be enriched under aerobic conditions through intermittent feeding with a mixture of organic acids. Enriching of activated sludge was monitored through the measurement of polymer concentrations either in the mixed liquor or in the microbial biomass. The bacterial population dynamics during the SBR start up was followed through denaturing gradient gel electrophoresis and the main species present at the steady state were identified. All the measured parameters significantly changed in the SBR during first two weeks after the inoculum was seeded into the reactor, they then stabilized. At the steady state, the SBR produced 2.6 gVSSl(-1) d(-1), with a PHA content of 11% (on a COD basis). The enriched microbial biomass was then transferred into a batch reactor where the bacterial polymer content was increased through a new feeding. In the final batch stage, maximum storage rate and maximum polymer content in the biomass were 405 mgCOD gCOD(-1) h(-1) and 44% (on a COD basis), respectively. The PHA storage from the enriched microbial biomass was about 20 times faster and the PHA content was about 4 times higher than that of the inoculated activated sludge. Observations by fluorescence microscopy showed that the majority of microorganisms in the enriched biomass could be stored. Among the numerically most representative genera in the enriched biomass, Thauera, Candidatus Meganema perideroedes, and Flavobacterium were identified.     

Energy saving processes for nitrogen removal in organic wastewater from food processing industries in Thailand.

Nitrogen removal from organic wastewater is becoming a demand in developed communities. The use of nitrite as intermediate in the treatment of wastewater has been largely ignored, but is actually a relevant energy saving process compared to conventional nitrification/denitrification using nitrate as intermediate. Full-scale results and pilot-scale results using this process are presented. The process needs some additional process considerations and process control to be utilized. Especially under tropical conditions the nitritation process will round easily, and it must be expected that many AS treatment plants in the food industry already produce NO2-N. This uncontrolled nitrogen conversion can be the main cause for sludge bulking problems. It is expected that sludge bulking problems in many cases can be solved just by changing the process control in order to run a more consequent nitritation. Theoretically this process will decrease the oxygen consumption for oxidation by 25% and the use of carbon source for the reduction will be decreased by 40% compared to the conventional process.     

Coupled anaerobic-aerobic treatment of whey wastewater in a sequencing batch reactor: proof of concept.

A proof of concept was performed in order to verify if the coupling of anaerobic and aerobic conditions inside the same digester could efficiently treat a reconstituted whey wastewater at 21 degrees C. The sequencing batch reactor (SBR) cycles combined initial anaerobic phase and final aerobic phase with reduced aeration. A series of 24 h cycles in 0.5 L digesters, with four different levels of oxygenation (none, 54, 108 and 182 mgO2 per gram of chemical oxygen demand (COD)), showed residual soluble chemical oxygen demand (sCOD) of 683 +/- 46, 720 +/- 33, 581 +/- 45, 1239 +/- 15 mg L(-1), respectively. Acetate and hydrogen specific activities were maintained for the anaerobic digester, but decreased by 10-25% for the acetate and by 20-50% for the hydrogen, in the coupled digesters. The experiment was repeated using 48 h cycles with limited aeration during 6 or 16 hours at 54 and 108 mgO2gCODinitial(-1), displaying residual sCOD of 177 +/- 43, 137 +/- 38, 104 +/- 22 and 112 +/- 9 mgL(-1) for the anaerobic and the coupled digesters, respectively. The coupled digesters recovered after a pH shock with residual sCOD as low as 132 mg L(-1) compared to 636 mg L(-1) for the anaerobic digester. With regard to the obtained results, the feasibility of the anaerobic-aerobic coupling in SBR digesters for the treatment of whey wastewater was demonstrated.     

己二酸酯生产废水处理工程设计与运行

采用三维电极法对CODCr高达120000mg/L的己二酸酯生产废水进行预处理,然后与生活污水混合,再采用两级ABR-接触氧化法进行处理,出水CODCr平均为301mg/L,达到《污水综合排放标准》(GB8978—1996)三级标准。该工艺操作简单、出水水质稳定,运行费用低。     

Biohydrogen production by mesophilic fermentation of food wastewater.

Batch experiments were conducted to convert molasses wastewater (10-160 g COD/L) into hydrogen at 35 degrees C at various pH (4-8). The maximum hydrogen productivity (HP) and hydrogen production rate (HPR) reached 47.1 mmol-H2/g COD(re) and 97.5 mmol-H2/L-day, respectively, at a substrate concentration of 40 g COD/L and pH 6.0. The methane-free biogas contained up to 50% (v/v) of hydrogen. Fermentation at wastewater concentrations higher than 60 g COD/L required a long acclimation period (more than 20 h). Though the fractions were substrate concentration and pH-dependent, acetate and butyrate were the two main liquid fermentation products. A comparison of the HP and HPR data indicates that defining a hydrogen yield indicator to evaluate hydrogen generation efficiency should be taken into consideration in practical fermentation operations.     

Performance comparison of a pilot-scale membrane bioreactor and a full-scale sequencing batch reactor with sand filtration: treatment of low strength wastewater from a northern Canadian Aboriginal Community.

Northern Aboriginal communities in Canada suffer from poor wastewater treatment. Treatment systems on 75% of Manitoban Aboriginal communities produce substandard effluent despite the presence of sophisticated treatment systems. A 200-litre, pilot-scale membrane bioreactor (MBR) was established on the Opaskwayak Cree Nation to investigate the feasibility of MBRs in mitigating Aboriginal wastewater treatment issues. The pilot system was remote controlled and monitored via the Internet using the program pcAnywhere. The community utilized two existing sequencing batch reactors (SBR) and three sand filters for wastewater treatment. The community wastewater was relatively weak and highly fluctuating which led to poorly settling sludge that readily fouled the sand filters. A comparison study between the MBR and SBR was undertaken from September to December 2003. Operated at a 10-hour hydraulic retention time and 20-day solids residence time, the MBR outperformed the SBR and sand filtration on BOD and suspended solids removal. Furthermore, the MBR showed high levels of nitrification despite relatively cold water temperatures.     

膜生物反应器处理食品废水的工程应用

介绍了MBR处理食品废水的工程效果。并在长期跟踪反应器跨膜阻力的基础上,重点探讨了膜离线和在线化学清洗的方法及结果,指出离线和在线化学清洗是控制和消除膜有机污染和无机污染的有效手段。离线化学清洗可以基本消除膜丝内表面的污染,对于膜丝外表面的污染也具有显著效果。     

Continuous and sequencing membrane bioreactors applied to food industry effluent treatment.

This work focuses on the performances of two immersed membrane bioreactors used for the treatment of easily biodegradable organic matter present in food industry effluents, for the purpose of water reuse. Two reactor functioning modes (continuous and sequencing) were compared in terms of organic carbon removal and of membrane permeability. For each working mode, pollutant removal was very high, treated water quality presented a low COD concentration (< 125 mg x L(-1)), no solids in suspension and low turbidity (< 0.5 NTU). The quality of the treated water (including germ removal) enabled its reuse on site. Moreover, by developing high biomass concentrations in the reactor, excess sludge production remained very low (< 0.1 gVSS x gCOD(-1)). The performances appeared slightly better for the continuous system (lower COD concentration in the effluent, < 50 mg x L(-1), and lower sludge production). In terms of filtration, a distinct difference was observed between continuous and sequencing systems; transmembrane pressure showed a small and constant evolution rate in continuous membrane bioreactor (CMBR) although it appeared more difficult to control in sequencing membrane bioreactor (SMBR) probably due to punctually higher permeate flow rate and modified suspension properties. The rapid evolution of membrane permeability observed in SMBR was such that more frequent chemical cleaning of the membrane system was required.     

Nitrogen removal of high strength wastewater via nitritation/denitritation using a sequencing batch reactor.

The sequencing batch reactor (SBR) process concept was applied to achieve efficient ammonium removal via nitrite under both laboratory and pilot-scale conditions. Both sets of experimental results show that without pH control or carbon addition the nitritation process consistently converted approximately 50% of the ammonium from biosolids dewatering liquids to nitrite with hydraulic retention times (HRT) as short as 10 h. The results from the pilot-scale study also indicate that the selective oxidation of ammonium to nitrite is a reliable process as the accumulation of nitrate was never an issue during a 330-day trial. The SBR process concept was extended to achieve complete nitrogen removal through nitritation and denitritation in the laboratory scale. The experimental results indicate that a total reduction of 96-98% of the ammonium nitrogen from biosolids dewatering liquids (influent concentration typically 1,200 g m(-3)) was achieved with a short HRT of 1.1 d and a removal rate of 1.05 kgNm(-3)d(-1). This process concept was tested at pilot scale where the nitritation process could be started up without temperature control in a short period of time. Nitrogen removal rates up to 1.2 kgNm(-3)d(-1) at an HRT of 0.88 d have been obtained. COD to nitrogen ratios required in the pilot plant were consistently in the range 1.6-1.9 kgCOD kg(-1)N removed.     

Photosynthetic bacteria pond system with infra-red transmitting filter for the treatment and recovery of organic carbon from industrial wastewater.

A photosynthetic bacteria pond system was applied to the treatment of food industrial wastewater and recovery of carbon in the form of purple non-sulphur bacterial (PnSB) cell. The effect of infra-red transmitting filter on the selection of microbial groups in the system was investigated. It was found that more than 90% of organic removal could be achieved when the system was operated at HRT of 3 to 10 days, even though some fluctuations were observed at lower HRT. Infra-red transmitting filter could suppress the growth of microalgae in the system and allow the purple non-sulphur to grow in the system. Nevertheless, they could be outgrown by sulphate-reducing bacteria at higher organic loading rates. The growth of purple sulphur bacteria associated with sulphate reducing bacteria was also observed. ORP is a crucial operating factor to control the system under micro-anaerobic conditions which is preferred to the growth of purple non-sulphur bacteria.