基于小孔径PVDF内衬膜A/O-MBR膜污染分析

为研究膜生物反应器膜污染问题,在缺氧-好氧一体式膜生物反应器中,对模拟生活污水的处理效果进行考察,考察了4种不同孔径聚偏氟乙烯(PVDF)内衬膜对膜污染的影响规律。结果表明,基于小孔径PVDF膜的MBR工艺对模拟生活污水中COD、NH3-N的去除率分别达到96%、90%,出水浊度在0.35 NTU以下;在操作条件固定的情况下,随着膜孔径增加,临界通量逐渐降低;孔径越小,跨膜压差上升越缓慢,膜污染较轻。膜污染模型分析结果显示:无论何种孔径的膜,在MBR系统中,滤饼层和凝胶层污染所占的比例都最大(>80%),因此,在使用过程中减缓滤饼层及凝胶层的形成至关重要。     

Elaboration of new tubular ceramic membrane from local Moroccan Perlite for microfiltration process. Application to treatment of industrial wastewaters

In this study, an original microfiltration tubular membrane (M1) made from local Moroccan Perlite was used to treat three wastewater types: effluents coming from beamhouse section of tannery (effluent A), textile effluent coming from jeans washing process (effluent B), and dicing wafer effluent generated by electronic industries (effluent C). The prepared membrane is composed of two layers of Perlite with two different granulometries: a macroporous support with a pore diameter centered near 6.6 μm and porosity of about 42%, and a microfiltration layer, performed by slip casting method, with a mean pore size of 0.27 μm. The water permeability determined of the membrane is 815 L/h m² bar. Tangential microfiltration using Perlite membrane proved to be effective in removing pollutants from the three effluents with almost the same efficiencies than that obtained with a commercial Alumina membrane (M2) with a pore diameter of 0.2 μm and a water permeability of 1022 L/h m² bar. Tangential microfiltration process operated at lower pressure (1 bar) was seen to remove turbidity from the three feeds completely. Perlite membrane allowed significant reduction of Chemical Oxygen Demand COD (50–54%) and Total Kjeldahl Nitrogen TKN (56%) of beamhouse effluent. It showed a significant decrease of COD (54–57%) and a complete discoloration of textile wastewater.     

Comparison of the operational characteristics between a nitrifying membrane bioreactor and a pre-denitrification membrane bioreactor process

A single submerged membrane bioreactor (MBR) for nitrification of ammonium and a pre-denitrification MBR process for total nitrogen (TN) removal were investigated in comparison. A single nitrifying MBR was fed with synthetic ammonium wastewater of up to 900 mgN/l without organics so that the MBR was maintained as a pure nitrifying system. A high nitrifying capacity around 1.8 kgNH₄-N/m³/day was achieved while keeping the ammonium oxidation rate above 98%. Sludge volume index (SVI) gradually decreased down to less than 50 indicating good settleability of nitrifying sludge. The increase of suction pressure was less than 5 cm Hg over 7-months of operation. TN removal efficiency was determined in a pre-denitrification configuration with an anoxic reactor. Synthetic wastewater of 1200 mgCOD/l and 200 mgN/l was fed to the system at loads of 2.4 kgCOD/m³/day and 0.4 kgN/m³/day, respectively. As the internal recycle ratio from aerobic to anoxic zone increased from 2 to 6, TN removal efficiency was enhanced from 70 ± 9 to 89 ± 3%. With the sludge concentration of around 12,000 mg/l, SVI was highly fluctuated from 60 to 350 indicating the partial deterioration of sludge settleability. The suction pressure after 8 months of operation increased to above 10 cm Hg which is higher than that in a single nitrifying MBR. The concentration of extracellular polymeric substances (EPS), especially for carbohydrate content, was higher in the operation of a pre-denitrification MBR process than in a single nitrifying MBR. It is likely that the sludge characteristic such as settleability is related with membrane fouling but, further extensive study is needed. The performance of a pre-denitrification MBR process was also verified with real petrochemical nitrogen wastewater.     

膜生物反应器的运行和膜污染特征

研究了膜生物反应器的运行效果、膜污染特征。结果表明：膜生物反应器具有良好的污染物去除效果,在处理生活污水时COD的去除草达到90％以上,出水COD控制在80mg·L^－1以下,NH4-N的去除效果能达到95％,出水NH4-N浓度10mg·L^-1以下,膜污染的过程呈现明显的“两段式”特点,即过膜压力缓慢上升阶段和快速上升阶段。采用NaOH＋NaClO联合清洗后,膜的过膜压力迅速下降,表明膜污染以有机污染为主。     

MBR-光催化氧化处理印染废水的试验研究

利用MBR-光催化氧化的组合工艺处理某纺织园区综合废水,对反应装置进行了连续运行效果的考察.结果表明,MBR对废水COD、浊度,色度降解率分别达到93.5%、99.9%和98.9%;MBR中污泥沉降性能明显优于SBR,能有效控制污泥膨胀现象;出水的透光性大大提高,经光催化氧化后COD、BOD、浊度、色度分别稳定在35.0mg·L~(-1)、2.7 mg·L~(-1),2.3NTU、3倍,水质达到GB 18918-2002的一级A排放标准和CJ/T48-1999的生活杂用水要求.     

平面显示面板生产有机工业废水的回用水处理技术

该文采用混凝沉淀、MBR和反渗透组合工艺装置针对平面显示面板生产有机废水进行深度处理。结果表明通过混凝沉淀,有机废水中的 COD能降低约10％,并减轻后续 MBR膜的有机物污堵。MBR装置出水能保持良好水质（TOC ＜10 mg/L、SDI15＜3）,很适合采用反渗透进行进一步处理。通过反渗透装置进行深度处理后,出水能达到TOC＜1 mg/L、电导率＜85μs/cm,可作为原水直接回用到超纯水制备系统。     

The effect of COD/N ratio on process performance and membrane fouling in a submerged bioreactor

Influent chemical oxygen demand/nitrogen (COD/N) ratio is used to control fouling in membrane bioreactor (MBR) systems. However, COD/N also affects the physicochemical and biological properties of MBR biomass. The current study examined the relationship between COD/N ratio in feed wastewater and extracellular polymeric substances (EPS) production in MBRs. Two identical submerged MBRs with different COD/N ratios of 10:1 and 5:1 were operated in parallel. The cation concentration and floc-size of the sludge were measured. The composition and characteristics of bound EPS and soluble microbial products (SMP) under each COD/N ratio were also examined. Batch tests were conducted in 1000 mL bottles to study the process of the release of foulants from the sludge when 1 g of (NH₄⁺-N)/L was added. Results showed that the influent COD/N ratio could change the physicochemical properties of EPS and SMP. Moreover, excessive NH₄⁺ in the supernatant could facilitate the role of NH₄⁺ as a monovalent cation, the replacement of the polyvalent cation in bound EPS, and even the extraction of EPS components from the surface of the sludge to form new SMP.     

Preparation of a composite coagulant: Polymeric aluminum ferric sulfate (PAFS) for wastewater treatment

A new composite coagulant polymeric aluminum ferric was synthesized and parameters affecting the coagulant performance such as reaction temperature and time, and OH/Fe, P/Fe and Al/Fe molar ratios in this study, were examined. In addition, to obtain the optimum synthetic conditions resulting in the maximum turbidity removal efficiency, response surface methodology (RSM) was used to assess their interactive effects on coagulation–flocculation performance. The results showed that reaction temperature (60–80 °C) and time (30–50 min), and OH/Fe (0.1–0.3), P/Fe (0.2–0.3) and Al/Fe (1:9–1:10) molar ratios were favorable to the preparation process. The optimum synthesis conditions were reaction temperature and time, and OH/Fe, P/Fe and Al/Fe molar ratios of 80 °C, 40 min, 0.1, 0.25 and 1:10, respectively. Evaluation of the coagulation–flocculation process showed that COD (chemical oxygen demand) and turbidity removal efficiency of 82.8% and 98.2%, respectively, were achieved at coagulant dosage of 45 mg/L, wastewater initial pH of 8.5, and rapid agitation speed of 250 rpm. In addition, charge neutralization and adsorption/bridging coagulation–flocculation mechanisms played an important role in reducing the surface charge of colloids.     

聚氯乙烯离心母液高品质回收工艺的研究

采用膜生物反应器(MBR)和反渗透(RO)工艺对聚氯乙烯离心母液废水进行回收。研究了该系统工艺对有机物和悬浮固体的处理效果以及系统的耐冲击能力;观察了生物相在MBR系统中的变化情况及MBR膜片和反渗透膜的污染情况。试验结果表明,该工艺在稳定运行的情况下,废水总COD去除率可达到95%以上,MBR出水COD浓度低于40 mg/L,达到直接排放标准,再经过反渗透、离子交换或连续电解除盐(EDI)处理后,出水可以达到聚合回用水标准,回收率达到70%以上,而且,整个试验过程中膜耐污染性能良好。     

复合式MBR处理涤纶碱减量废水的试验研究

以柔性多孔颗粒作为填料组成的复合式膜生物反应器(MBR)处理涤纶碱减量废水.结果表明,在控制HRT不变的条件下,进水COD从812.35 mg/L提高到1 621.24 mg/L,系统出水COD为26.60～68.03mg/L.系统的COD总去除率均在95%左右.有机负荷冲击对处理效果影响不大.膜组件有效截留有机污染物,确保系统稳定出水.复合膜生物反应器中的生物去除率略高于普通MBR.柔性填料对减轻膜污染贡献明显,相同运行条件下,使最终透膜压差比普通MBR小28.3kPa.     

软硬性填料对MBR处理效率和膜污染的影响

膜生物反应器（MBR）在污水处理领域的应用日益广泛,填料的投加对MBR污水处理效率和膜污染进程有一定的影响。本文分别向MBR中投加不同量的软性和硬性悬浮填料,研究了悬浮填料对MBR运行效率及膜污染的影响。结果表明,投加填料后MBR对COD、氨氮和总磷等污染物的处理效率有所提高,明显减缓了膜污染的进程。软性填料对MBR的改善效果优于硬性填料,投加20%的软性填料时,系统对COD、氨氮和总磷的去除率分别可达96.53%、98.21%和52.75%,系统运行30天时的膜污染情况比未投加填料的系统减缓了41.43%。通过对比发现软性填料能够为微生物提供更大的生存空间,提高反应器内的微生物量,从而提高MBR对污水的处理效率同时改善膜污染,是一种加强MBR系统的适宜填料,最佳投加量为反应器有效体积的20%。     

膜生物反应器在PTA废水深度处理中的应用

在PTA废水深度处理工艺中,膜生物反应器具有较高的浊度、COD的去除率,出水水质较好,在冲击性试验中也表现出良好的工艺稳定性。通过合理设计膜组件的结构和选择恰当的运行方式,可减少膜污染,延长膜清洗周期。     

污泥形态变化对膜生物反应器处理性能及膜污染的影响

通过对膜生物反应器(MBR)系统中污泥颗粒变化和处理模拟废水水质的监测,考察了污泥形态变化对MBR处理性能和膜污染的影响。结果表明:MBR中颗粒有保持均匀分布并缓慢减小的趋势,颗粒大小对COD去除有一定影响,对氮磷的去除影响甚微,但是会加速膜污染。     

组合工艺处理医院生活污水的对比研究

分别采用接触氧化组合工艺和MBR组合工艺处理医院生活污水,对处理效果及运行费用进行了对比。结果表明:接触氧化组合工艺处理效果受填料比影响较大,当填料比为20%时,对COD、氨氮、浊度的去除率最高分别为88%、88%、96%;处理同样医院废水的情况下,MBR组合工艺对COD、氨氮、浊度的去除率最高分别为75%、79%、98%,由于截留能力的差异,MBR出水中的微生物含量显著低于接触氧化出水,在满足排放标准情况下,MBR组合工艺的消毒剂用量相对较低;经济分析表明,同等规模的组合工艺,两者的总投资相差不大,MBR组合工艺的运行费用略高。     

膜生物反应器工艺处理炼油废水中试研究

采用中空纤维膜生物反应器(MBR)工艺处理炼油废水,了解膜生物反应器在炼油废水处理中的性能.研究结果表明,采用膜生物反应器工艺可有效地处理炼油废水,COD、氨氮和油去除率分别为91.5%、96.7%、84.7%,MBR出水COD为64 mg/L,氨氮为1.85 mg/L,油含量<3.0 mg/L,出水水质达到国家一级排放标准.     

臭氧氧化处理渗滤液纳滤浓缩液的试验研究

采用臭氧为主工艺处理垃圾渗滤液纳滤浓缩液,试验结果表明:先通过混凝沉淀、臭氧氧化,再采用MBR处理,可取得良好的处理效果。当三氯化铁的投加量为2 kg/m3,PAM的投加量为0.1 kg/m3,絮凝时间在30~40 min,沉淀时间2~3 h的条件下,混凝沉淀COD的去除率为45%~60%;臭氧用量在25 g/h,水力停留时间为90 min左右,B/C比可提高至0.45;氧化后废水在MBR作用下出水COD为1000 mg/L左右,COD去除率为50%;如出水达到GB16889-2008标准限值的要求,需增加深度处理。     

Comparative Studies on Coagulation and Adsorption as a Pretreatment Method for the Performance Improvement of Submerged MF Membrane for Secondary Domestic Wastewater Treatment

Abstract

Membrane fouling is the main limitation of water and wastewater treatment. Coagulation and adsorption can remove organic materials which play an important role in fouling phenomena. Thus, this study focused on the comparison of the hybrid process of coagulation and adsorption coupled with microfiltration (MF) membrane for the secondary domestic wastewater from an apartment complex in Gwangju city, South Korea. Coagulation and adsorption were adopted as a pretreatment method prior to MF treatment. Three different powdered activated carbon (PAC) and ferric chloride were used as an adsorbent and as a coagulant. MF was operated in a submerged mode using hollow fiber polyethylene membrane with pore size of 0.4 µm for the separation of suspended organic solids resulted from coagulation or PAC particles, which are used for adsorbing organics dissolved in wastewater. Prior to study on the hybrid system, the performance of coagulation and adsorption processes were optimized individually for the removal of organics. Then, the overall performance for the hybrid system of coagulation/MF and PAC/MF was evaluated based on TOC removal, turbidity removal, and flux decline. It was found that the combined coagulation/MF and PAC/MF showed similar performance for TOC removal while coagulation/MF resulted in a significant decrease of the flux decline.     

膜生物反应器+反渗透工艺对再造烟叶废水的处理

采用膜生物反应器(MBR)和反渗透(RO)组合工艺,深度处理再造烟叶生产的废水。结果表明:经"MBR+RO"处理后,废水的COD、色度、氨氮、浊度等的去除率均达到95%以上,RO出水(回用水)完全可以满足生产需要,部分指标优于生活饮用水。     

Dyeing and printing wastewater treatment using a membrane bioreactor with a gravity drain

A laboratory-scale membrane bioreactor (MBR) with a gravity drain was tested for dyeing and printing wastewater treatment from a wool mill. The MBR was operated with continuous permeate by gravity and without chemical cleaning for 135 days. Results showed that excellent effluent quality could meet the reuse water standard in China. The average concentrations of COD, BOD₅, turbidity and color in the effluent were 36.9 mg l⁻¹, 3.7 mg l⁻¹, 0.2 NTU and 21 dilution times (DT), respectively. The average removal rates of COD, BOD₅, turbidity and color were 80.3%, 95.0%, 99.3% and 58.7%, respectively. The membrane flux increased with increasing of aeration intensity, and its increasing rate was related to pressure-heads. The higher the pressure-head, the greater the impact of aeration intensity on membrane flux. Statistical analysis also showed that both the pressure-head and aeration intensity significantly affected membrane flux. Due to its compact design, simple operation and easy maintenance, MBR with a gravitational filtration system hs low energy consumption and is cost-effective to build and operate. If the life expectancy of the membrane is set for 3–4 years and the membrane flux is set at 15 l/m²·h, such a MBR would be very competitive.     

Removal of nitrogen from wastewater for reusing to boiler feed-water by an anaerobic/aerobic/membrane bioreactor

The innovative process anaerobic/aerobic/membrane bioreactor (A/O/MBR) was developed to enhance pre-denitrification without the energy consumption of the recirculation pump for reusing wastewater to boiler feed-water. The performance of this bioreactor was investigated. Firstly, the septic tank wastewater with low ratio of COD/TN was disposed by a dynamic membrane bioreactor (DMBR). It was found that, although the high concentration of NO₂⁻–N in the effluent implied the potential ability of DMBR to realize shortcut nitrification and denitrification, the effluent of single DMBR was difficult to reach the criteria of reusing to boiler feed-water. Then, the process A/O/DMBR in disposing the septic tank wastewater was studied. The results indicated that this process not only accomplished the removal of 91.5% COD, 90.3% NH₄⁺–N and 60.2% TN, but also successfully realized pre-denitrification without additional recirculation pump. At last, based on the A/O/DMBR, a pilot plant A/O/MBR was built to dispose the municipal raw sewage. In the stable operation period, the average removal efficiencies for COD, NH₄⁺–N, TP and turbidity reached 90%, 95%, 70% and 99%, respectively. During the tested HRT run of 9.0 h, the effluent of COD, NH₄⁺–N, TP and turbidity was about 10 mg/L, 3 mg/L, below 1 mg/L and 1.2 NTU, respectively, which reached the criteria of the boiler feed-water in China.