厌氧-膜过滤联用工艺处理屠宰废水的研究

采用完全混合型厌氧生物反应器处理高悬浮物含量的屠宰废水,并经过外置错流式超滤膜组件进行泥水分离。研究表明该系统具有很短的启动期,稳定运行后在不同容积负荷条件下均能取得很高的有机物去除率,在半年运行期内对化学需氧量(COD)的平均去除率为91.65%,系统的最高COD容积负荷可达到8.0 g/(L.d);稳定运行期间系统去除COD的甲烷产率处于0.20—0.30 L/g。该工艺实现了厌氧污泥与进水悬浮物的完全截留,对高悬浮性的复杂工业废水具有很好的处理效果。     

Biodegradability of slaughterhouse wastewater with high blood content under anaerobic and aerobic conditions

In this work, the biodegradability of wastewater from a slaughterhouse located in Ke?an, Turkey, was studied under aerobic and anaerobic conditions. A very high total COD content of 7230 mg dm^?3 was found, due to an inefficient blood recovery system. Low BOD₅/COD ratio, high organic nitrogen and soluble COD contents, were in accordance with a high blood content. A respirometry test for COD fractionation showed a very low readily biodegradable fraction (S_S) of 2%, a rapidly hydrolysable fraction (S_H) of 51%, a slowly hydrolysable fraction (X_S) of 33% and an inert fraction of 6%. Kinetic analysis revealed that hydrolysis rates were much slower than these of domestic sewage. The results underlined the need for an anaerobic stage prior to aerobic treatment. Tests with an anaerobic batch reactor indicated efficient COD degradation, up to around 80% removal. Further anaerobic degradation of the remaining COD was much slower and resulted in the build up of inert COD compounds generated as part of the metabolic activities in the anaerobic reactor. Accordingly, it is suggested that an appropriate combination of anaerobic and aerobic reactors would have to limit anaerobic degradation to around 80% of the tCOD and an effluent concentration above 1000 mg dm^?3, for the optimum operation of the following aerobic stage. © 2003 Society of Chemical Industry     

The start‐up of anaerobic sequencing batch reactors at 20 °C and 25 °C for the treatment of slaughterhouse wastewater

The objective of this research was to evaluate the feasibility, the stability and the efficiency of a start‐up at 20 °C and 25 °C of anaerobic sequencing batch reactors (ASBRs) treating slaughterhouse wastewater. Influent chemical oxygen demand (COD) and suspended solids concentrations averaged 7500 and 1700 mg dm^?3, respectively. Reactor start‐up was completed in 168 and 136 days at 20 °C, and 25 °C, respectively. The start‐up process was stable at both temperatures, except for a short period at 20 °C, when effluent volatile fatty acid (VFA) concentrations increased from an average of 40 to 400 mg dm^?3. Effluent quality varied throughout start‐up, but in the last 25 days of the experiment, as the ASBRs were operated under organic loading rates of 2.25 ± 0.21 and 2.86 ± 0.24 kg m^?3 d^?1 at 20 °C and 25 °C, respectively, total COD was reduced by 90.3% ± 1.3%. Methanogenesis was not a limiting factor during start‐up. At 20 °C, the limiting factor was the acidification of the soluble organics and, to a smaller extent, the reduction of propionic, isobutyric and isovaleric acids into lower VFAs. At 25 °C, the limiting factor was the hydrolysis of particulate organics. To minimize biomass loss during the start‐up period, the organic loading rate should be increased only when 75 –80% of the COD fed has been transformed into methane within the design hydraulic retention time. © 2001 Society of Chemical Industry     

厌氧流化床处理红霉素废水的研究

研究了中温(33～35℃)条件下,厌氧流化床(AFB)反应器处理红霉素废水的运行特性.结果发现:进水COD为6 900 mg/L、HRT为4.4 h时,COD、BOD的去除率分别达到了76.6%、65.9%.最后利用Garrett-Sawyer关系式求出了难生物降解的有机物浓度,并利用Monod模型对实验结果进行了动力学分析,得出了红霉素废水中温条件下厌氧消化过程的基质降解规律.     

厌氧折流板反应器在废水处理中的研究与应用

综述了国内外厌氧折流板反应器(ABR)应用于废水处理的研究进展,从ABR的启动和进水方式、出水循环和增设填料、处理低浓度和高浓度废水等方面分析了ABR的特点和优缺点,并在此基础上提出了今后ABR的研究发展方向。     

厌氧折流板反应器性能研究进展

综述了厌氧折流板反应器(ABR)自问世以来关于其水力特性、污泥特性及抗冲击负荷能力三方面的研究工作;分析了进行这些研究工作的意义;指出尽管ABR拥有许多优于其他厌氧工艺的特点。但仍然可以通过结构及工艺的改进,处理更多难降解废水,这在我国高浓度工业有机废水和有毒废水的处理中具有良好的研究开发价值和广阔的应用前景。     

Hydrodynamic behaviour of a full‐scale anaerobic contact reactor using residence time distribution technique

BACKGROUND: The knowledge of the fluid pattern of full‐scale anaerobic reactors is of fundamental importance for the optimisation of biological processes. High solids concentrations often lead to inefficient mixing conditions, which may reduce treatment capacity due to heterogeneity within the biomass. RESULTS: The hydrodynamic characteristics of a full‐scale anaerobic contact reactor treating evaporator condensate from a sulphite pulp mill were investigated. The methodology applied was based on the residence time distribution (RTD) technique using lithium as a tracer. Different non‐ideal hydraulic flow models were tested and the best model fitting RTD data was the Gamma distribution model with by‐pass. It was concluded that the full‐scale bioreactor presents a good degree of mixing with about 22% of non‐effective volume due to the presence of high amounts of inorganic materials. CONCLUSION: As a result of this study it was possible to both improve the full‐scale bioreactor performance and decrease the running costs by changes in the plant operation strategies which allowed reduction of the huge amount of inorganic materials contributing to the non‐effective volume. The methodology is simple and results from a unique RTD experiment and confirms the importance of considering mixing characteristics when assessing complex full‐scale treatment processes. Copyright © 2009 Society of Chemical Industry     

The effect of an enzymatic pretreatment on the hydrolysis and size reduction of fat particles in slaughterhouse wastewater

The effect of an enzymatic pretreatment, Pancreatic Lipase 250 (PL‐250), on the hydrolysis and size reduction of fat particles in slaughterhouse wastewater was characterised for enzyme doses ranging from 125 to 1000 mg dm^?3 and initial particle sizes (D_in) varying between 53 and 383 µm. Treatment with PL‐250 significantly reduced the size of pork fat particles in slaughterhouse wastewater. Particle size reduction increased with D_in, possibly due to the more filamentous and plate‐like configuration of the larger fat particles, which could be easily broken at weak points. The smaller particles were observed to be denser and more spherical. Size reduction also increased with enzyme concentration, but the benefit of adding more enzyme diminished greatly as enzyme dose was increased. The maximum long‐chain fatty acid (LCFA) concentration in filtered samples was detected after 4–7 h of treatment and ranged from 8.2 to 34.9 mg dm^?3. The linear rate of LCFA released in solution during enzymatic pretreatment ranged from 39.4 to 169.9 mg dm^?3 d^?1, and increased with enzyme concentration up to 500 mg dm^?3. At a PL‐250 concentration of 1000 mg dm^?3, the LCFA release rate decreased, maybe due to excessive layering of adsorbed enzyme on the fat particles or increased degradation of released LCFAs. The pretreatment appeared to be more efficient with beef than pork fat particles. However, the effect of an enzymatic pretreatment on a downstream anaerobic treatment of slaughterhouse wastewater containing fat particles remains to be tested. © 2001 Society of Chemical Industry     

厌氧折流板反应器处理退浆废水的启动研究

对采用厌氧折流板反应器(ABR)处理难降解退浆废水的启动过程进行了研究.实验结果表明:经过90 d的运行,反应器在32～34℃、上流速度8 m/h、水力停留时间6 d、COD容积负荷1.80 kg/(m3·d)的条件下,COD去除率达到55%以上,启动成功.出水COD稳定在4 500 mg/L左右,碱度约为700～850 mg/L.运行情况表明,启动初期反应器各隔室的pH变化较大,有效控制pH是系统启动成功的关键.启动后期,各隔室pH稳定在6.8～7.3之间,挥发性脂肪酸(VFA)质量浓度为300～500mg/L.随着隔室的横向推移,污泥的SS、VSS和SS/VSS不断增大,推测反应器中厌氧微生物相分离现象显著.     

A three‐phase fluidized bed reactor in the combined anaerobic/aerobic treatment of wastewater

Aerobic degradation or polishing is an essential step in the combined anaerobic/aerobic treatment of wastewater. In this study, a type of porous glass beads was used for immobilization of microbial cells in a three‐phase aerobic fluidized bed reactor (AFBR) with an external liquid circulation. The effects of superficial gas and liquid velocities on bed expansion, solid and gas hold‐ups and specific oxygen mass transfer rate, k_La, were investigated. A tracer study showed that the mixing and flow pattern in the 8 dm³ reactor could be simulated by a non‐ideal model of two continuous stirred tank reactors (CSTRs) in series. By treating an effluent from an upflow anaerobic sludge blanket (UASB) digester, the distribution of suspended and immobilized biomass in the reactor as well as the kinetics of COD removal were determined. The specific oxygen mass transfer rate, k_La, at a superficial gas velocity of 0.7 cm s⁻¹ dropped by about 30% from 32 h⁻¹ in tap water to 22 h⁻¹ after a carrier load of 15% (v/v) was added. The measured k_La further dropped by about 20% to 18 h⁻¹ in the wastewater, a typical value of the bubbling fermenters with no stirring. Compared with the aerobic heterotrophs under optimum growth conditions, the microbes in this reactor which was fed with anaerobic effluent plus biomass behaved like oligotrophs and showed slow specific COD removal rates. This might be attributed to the presence of a significant amount of obligate anaerobes and facultative organisms in the aerobic reactor. This was confirmed by a relatively low intrinsic oxygen uptake rate of the microbial population in the reactor, 94 mg O₂ dm⁻³ h⁻¹ or 19 mg O₂g VS⁻¹ h⁻¹. © 1999 Society of Chemical Industry     

挡板式水解酸化法处理印染废水的中试试验研究

对印染废水进行了挡板式水解酸化中试试验。结果表明,调节原水pH值为10左右,污泥质量浓度为20g/L,水力停留时间为9～10h的条件下,处理后的废水COD去除率平均为38．6％,进出水的BOD／COD比值由0．285升高至0．447,废水可生化性能得到明显改善。挡板式水解酸化法作为印染废水好氧生物处理的前处理在技术上和经济上都是可行的。     

甘蔗渣湿法堆垛高浓度有机废水厌氧处理实验研究

对甘蔗渣喷淋废水进行了一系列的厌氧处理实验研究。结果表明，厌氧处理对废水中的CODcr及BOD5的去除有显著的效果。当废水的pH为7.5，水温为30-40℃，CODcr及BOD5分别为3000-9000mg/L和2000-5000mg/L时，CODcr及BOD5的去除率分别为90%和94%，为该废水治理达标排放奠定了基础。     

Heterogeneous anionic ring opening polymerization in a fixed‐bed reactor: description of the process and modelling

Grafting active centres on a solid porous support and using alcohol molecules as a transfer agent permitted coordinated anionic ring opening polymerization of oxygenated heterocycles by a continuous process. Dehydrated porous silica or alumina have been employed as solid supports. After grafting aluminium alkoxides on these supports, ε‐caprolactone and dimethyltrimethylene carbonate have been polymerized. Conversion as well as molecular weights were dependent on the contact time of reactants within the porous phase. A model of this continuous process has been developed by a combination of a Monte Carlo simulation with a reactor model based on the contact time distribution concept. Copyright © 2004 Society of Chemical Industry     

屠宰废水处理工艺设计与运行研究

以沈阳某屠宰厂为例,介绍了气浮—水解酸化—接触氧化工艺在该屠宰废水处理工程中的应用。通过在好氧段投加高效菌的方式,更有效地去除水中的COD、BOD5。运行结果表明:工艺可行且管理方便,投资、运行费用低,处理效果稳定,出水水质可达到《肉类加工工业水污染物排放标准》(GB 13457—1992)的一级排放标准。     

Biological treatment of saline wastewaters from marine‐products processing factories by a fixed‐bed reactor

Wastewaters generated by a factory processing marine products are characterized by high concentrations of organic compounds and salt constituents (>30 g dm^?3). Biological treatment of these saline wastewaters in conventional systems usually results in low chemical oxygen demand (COD) removal efficiency, because of the plasmolysis of the organisms. In order to overcome this problem a specific flora was adapted to the wastewater from the fish‐processing industry by a gradual increase in salt concentrations. Biological treatment of this effluent was then studied in a continuous fixed biofilm reactor. Experiments were conducted at different organic loading rates (OLR), varying from 250 to 1000 mg COD dm^?3 day^?1. Under low OLR (250 mg COD dm^?3 day^?1), COD and total organic carbon (TOC) removal efficiencies were 92.5 and 95.4%, respectively. Thereafter, fluctuations in COD and TOC were observed during the experiment, provoked by the progressive increase of OLR and the nature of the wastewater introduced. High COD (87%) and TOC (99%) removal efficiencies were obtained at 1000 mg COD dm^?3 day^?1. © 2002 Society of Chemical Industry     

Application of residence time distribution technique to the study of the hydrodynamic behaviour of a full‐scale wastewater treatment plant plug‐flow bioreactor

The hydrodynamic behaviour of a full‐scale wastewater treatment plant (WWTP) bioreactor treating municipal wastewater, situated in Granollers (Barcelona, Spain), has been studied by means of a residence time distribution (RTD) technique using lithium (chloride) as tracer. The bioreactor studied is designed to work as a plug‐flow reactor and it is divided into two independent lanes (1 and 2), each one composed of four compartments in series resulting in a total volume of 3970 m³ per lane. During the RTD experiments, working flow was 1000 m³ h^?1 per lane, which implied an ideal mean residence time of 3.97 h. When a lithium chloride tracer was injected in the bioreactor, both lanes showed a similar highly non‐ideal hydrodynamic behaviour, which had an important effect on the reactor's performance. This global RTD was complemented by means of local RTDs in different locations of the bioreactor in order to determine qualitatively the reactor's mixing regime. Different non‐ideal models (namely axial dispersion, tanks‐in‐series and some simple compartment models) have been tested for the modelling of the experimental RTD. The best model fitting RTD data for Lanes 1 and 2 was a configuration consisting of four mixed tanks in series. The RTD study proposed in this work will permit improvement of the reactor's mixing performance, which is of special interest in future projects including simultaneous removal of carbon, nitrogen and phosphorus. Copyright © 2005 Society of Chemical Industry