MBR工艺处理啤酒废水的工程应用

根据啤酒废水的特点,考察了采用膜生物反应器(MBR)技术深度处理啤酒废水过程中的水质指标与设备运行参数,并对污泥浓度进行测定,从而对污泥负荷以及膜污染状况进行研究,工程运行结果表明:在进水CODCr642～1626mg/L、NH4+-N15～35mg/L、TP0.6～14mg/L、TN19.5～41.1mg/L情况下,MBR产水CODCr50mg/L、NH4+-N5mg/L、TP0.3mg/L、TN2.3mg/L。水质达到国家景观用水标准(GB/T18921—2002);好氧池DO控制在2～4mg/L,可有效提高氨氮的去除率;适当调整排泥量,使膜池污泥质量浓度维持在6～8g/L可缓解膜污染速度。     

膜生物反应器去除原水中微量2,4,6-三氯酚的研究

2,4,6-三氯酚(2-4-6-trichlorophenol-TCP)普遍存在于地表水和工业废水中.采用一体式膜生物反应器(Membrane bioreactor-MBR)进行去除微污染湖水中微量TCP(40～360 μg/L)的试验.结果表明:稳定运行后MBR对TCP的平均去除率为98.13%.连续试验发现,在进水TCP浓度呈现明显波动的情况下,出水平均浓度为2.66μg/L,满足城市供水水质标准(CJ/T206-2005)规定的要求.同时采用间歇试验对MBR去除TCP的动力学机理进行了研究,证实生物作用在TCP的去除中起主要作用.MBR对TCP的去除符合零级动力学过程,降解速率常数为1.65μg/L·min.     

膜生物流化床膜污染的影响因素研究

膜生物流化床(MB阳)是将传统生物流化床与膜生物反应器(MBR)有机结合的产物.试验采用恒定膜通量间歇出水方式,以跨膜压力(TMP)随时间的变化情况为考察指标,研究了膜通量、曝气强度、出水抽/停时间对MBFB膜污染的影响.结果表明,在次l临界通量条件下(3.2～8.2L·m·h-1),MBFB膜污染速率得到明显控制;曝气强度对TMP上升速率影响显著;连续抽吸时间对膜污染的影响比停抽时间更为明显.在总生物浓度为8.0 g·L-1左右时,膜通量为5 L·m-2·h-1,气水比为25:1、出水抽/停时间为5～7 min/3 min的条件下,可控制MBFB的膜污染始终保持在较低水平.     

膜生物反应器膜污染泥饼层剥落研究

膜生物反应器(MBR)是一种由膜分离单元与生物处理单元相结合的水处理技术。MBR具有出水水良好,效率高等特点,成为最受欢迎污水处理工艺之一。由于MBR膜分离单元易产生淤塞造成膜污染,阻碍了其发展。膜污染是指混合液中的微粒及溶质大分子与膜存在着物理、化学或生物作用而在膜表面或膜孔内部沉积,造成膜孔变小或堵塞,进而在膜面形成泥饼层,使得膜通量减小和TMP增加的现象。因此研究膜污染泥饼层的剥落机理对MBR有重要意义。通常MBR泥饼层剥落量取决于曝气量,曝气孔径,曝气时间等。本实验表明:曝气量小,泥饼层(SS)剥落量在膜上中下三部分相差不大;曝气量大,膜下方泥饼层SS剥落大,泥饼层厚度与SS剥落一致。而胞外聚合物(EPS)(mg/gvss)是冲刷后反而增加,因为曝气只能冲刷掉SS,而作为膜污染主要因素EPS则很难去除,即曝气的剥落作用对EPS的去除不明显,得出结论物理清洗并不能有效防止膜污染。     

复合式MBR与改进式MBR处理造纸废水的研究

改进式MBR和复合式IVIBR装置,在pH为 6.5～8.5、HRT为10 h、温度为29℃的条件下,稳定运行近1个月,复合式MBR的平均出水水质分别为COD 110.17mg/L、BOD510.94mg/L、色度52倍;改进式IVlBR的平均出水水质分别为COD 126.75 mg/L、BOD 518.34 mg/L、色度6l倍,略差于复合式MBR.通过上清液分析发现,主要是因为复合式MBR中的膜组件上凝胶层起了更大的拦截作用.另一方面,阻力分布试验也表明,由于浓差极化和膜污染产生的阻力,复合式MBR大约是膜自身阻力的35.23倍,改进式MBR仅是膜自身阻力的6.36倍,说明复合式MBR更易引起膜污染.     

MBR反应器中SMP的研究

膜生物反应器(MBR)在水处理领域的应用已引起人们的广泛关注。然而膜污染已成为制约MBR反应器广泛应用的主要障碍,其中溶解性微生物产物(SMP)又是影响膜污染的重要因素。为此,介绍了MBR反应器的膜污染成因与SMP膜污染机理,综述了近年来国内外关于SMP的成因及其对膜污染影响的研究进展,并对SMP的研究模型进行了总结,最后提出了SMP膜污染的防治措施,以利于MBR反应器的推广应用。     

膜生物反应器中膜污染控制技术的研究进展

膜污染是膜生物反应器(MBR)运行的必然结果,是MBR大面积推广的严重阻碍,因此研究膜污染控制技术具有重要意义。从膜污染发生前的预防和膜污染发生后的清洗2个方面,论述了常见的各种膜污染控制手段,综述了膜污染控制技术的研究现状与进展。其中膜污染的预防手段主要有膜(膜组件)固有性质的改进、操作条件的优化以及混合液性状的调控3类,而膜污染的清洗手段按是否使用药剂可分为物理清洗和化学清洗2类。综合考察MBR运行中的膜污染状况,采用合理的方法对膜污染进行控制,能够有效延长膜的使用寿命,提高MBR的实用性能。     

某垃圾渗滤液处理站MBR出水异常原因分析及补救措施

为保证垃圾渗滤液处理工艺出水的达标排放,膜生物反应器（MBR）工艺和纳滤（NF）深度处理工艺均需高效稳定地运行。MBR膜元件性能是保障高效泥水分离、满足NF进水要求的基本要素。试验结果表明,MBR工艺长期运行后,出水COD高于1500 mg/L,膜片表面受到氧化或者物理损伤,且膜元件受到污染,膜性能降低;NF工艺有效截留有机物是保证渗滤液出水达标的另一要素,进水混凝预处理可在MBR膜性能不稳定的情况下实现NF进水水质稳定,从而使渗滤液达标排放。当絮凝剂添加量为2 mL/L时,出水COD为1365.5 mg/L,满足NF进水要求的同时处理成本仅为0.68元/t。在MBR膜元件性能降低时,混凝预处理是保证出水达标排放的紧急补救措施。     

两级序批式MBR膜污染控制方法研究

针对MBR在实际应用过程中存在的同步脱氮除磷效果不佳、膜污染严重等问题,提出两级序批式MBR工艺,对该工艺的膜污染影响因素及控制方法进行了试验研究.结果表明,在MBR中保持适宜的污泥质量浓度对于膜污染的控制有重要的作用,当污泥质量浓度稳定在6～7g·L~(-1)时,膜比流量基本稳定,随着污泥质量浓度的增加,膜比流量逐步降低,当污泥质量浓度超过10g·L~(-1)以后,膜比流量直线下降;投加PAC至1 g·L~(-1)可以增加污泥粒径,减少大分子有机物在膜表面沉积,从而有助于延缓膜污染;序批式间歇运行与空曝相结合的运行方式可以有效降低泥饼层污染及凝胶层污染,使系统在更高膜通量下运行,而膜污染速率却远低于连续流单级好氧MBR系统.     

平板膜材料基本性质评价及在膜-生物反应器运行性能研究

将膜材质特性与MBR运行状况相结合,进行3种膜的对比研究。对3种膜进行膜表面形态、接触角、膜厚度、孔隙率及力学机械性能的测定,考察不同材质的膜组件在MBR中稳定运行时跨膜压差变化情况,并测定DOM不同组分的膜污染速率和SMP截留率。结果表明,膜面表观性能最好,孔径分布均匀,不同方向上机械性能差异最小的JP膜,在MBR实际运行中表现出最强的抗污染性能,因此确定JP膜为最优膜;MBR中DOM的中性亲水性(HPI-N)组份所占比例最大,而HPO组份表现出了最强的污染趋势;不同膜材质对SMP有不同程度的截留,但SMP截留量与膜污染并没有直接联系。     

PAC投加量对MBR混合液性质及膜污染的影响

比较了1g／L及2g／L的PAC投加量对膜生物反应器中混合液性质及膜污染速率的差异。发现两系统上清液COD差距不明显,说明1g／L的PAC投加量忆足以吸附小分子的有机物。当PAC从1g／L增至2g／L时,从微生物絮体中提取的多糖平均值分别为：14．92mg／gMLSS、15．38mg／gMLSS;蛋白质平均值分别为18．82mg／gMLSS、17．58mg／gMLSS;且膜丝内部累积的多糖和蛋白质含量基本相同。当PAC投加量为2g／L时,部分破碎的PAC颗粒会进入膜孔内部,引起不可逆污染。     

重力出流式膜生物反应器污泥浓度的优化控制

采用重力出流式膜生物反应器(Membrane Bioreactor, MBR)工艺对生活污水进行了实验研究. 重力出流式MBR是利用液位水头重力驱动出水,整个系统结构紧凑,操作简便. 结果表明,随着污泥浓度增大(3.9~18.4 g/L),同样的曝气强度对膜表面滤饼层的剪切能力降低,膜通量下降;污泥粘度从5.4 mPa×s上升到680 mPa×s,相应的污泥中的传氧系数与清水中的传氧系数之比a从0.89降到0.10. 因此,从提高膜通量、氧传递速率和降低能耗的角度出发,将MBR的污泥浓度控制在适当范围是非常必要的. 此外,当污泥浓度大于4.8 g/L,污泥浓度的提高对有机物的去除、硝化以及反硝化速率的提高没有明显的贡献. 因此,从MBR的处理能力和运行能耗的双重影响确定MBR的最佳处理污泥浓度值为4~6 g/L,在该浓度区间,生物反应器系统对冲击负荷有较好的抵御能力,同时系统的运行能耗也较低.     

Operation of Membrane Bioreactor with Powdered Activated Carbon Addition

Abstract

The effect of powdered activated carbon (PAC) addition to the activated sludge (AS) in a membrane bioreactor (MBR) has been investigated. The long term nature of the tests allowed the PAC to gradually incorporate into the biofloc forming biologically activated carbon (BAC). One series of tests involved 4 bench scale (2 L) MBRs operated at sludge retention times (SRTs) of 30 days with PAC inventories of 0, 1, 3 and 5 g/L and steady state biomass concentrations of 12.0±1.0 g/L. The characteristics of the mixed liquors (MLSS) from the 4 reactors were compared. Short term filtration tests, including measurement of specific cake resistance (SCR), flux decline profile, and irreversible fouling resistance in an unstirred cell and “sustainable” flux (by monitoring transmembrane pressure (TMP) rise) in a crossflow cell all showed better filtration performance for the MLSS with BAC compared with the AS alone. In terms of SCR and flux decline profile the 1 g/L PAC addition performed best, but in terms of minimizing irreversible membrane fouling and maximizing “sustainable” flux the 5 g/L PAC was best. All 4 systems showed lower total organic carbon (TOC) in the permeate compared to the bioreactors, but the lowest permeate TOC (and the best removal) was for the highest PAC loading.

The benefit of PAC addition was confirmed in a second series of tests with two 20 L MBRs with submerged hollow fibers, one operated without PAC, the MBR(AS), and the other with 5 g/L PAC, the MBR(BAC). For an SRT of 30 days (which involved 3.3% sludge wastage per day and 3.3% new PAC addition per day) and a fixed flux of 21 L/m²hr the MBR(AS) showed a TMP rise of about 2.4 kPa/day whereas the MBR(BAC) showed a rise of only 0.8 kPa/day. However when the MBRs were operated without wastage the performance of the MBR(BAC) was worse than the MBR(AS). Thus the improved performance of the MBR(BAC) requires regular replenishment of aged BAC with fresh PAC.     

New configuration of a membrane bioreactor for effective control of membrane fouling and nutrients removal in wastewater treatment

Excess aeration to membrane surface is common for controlling membrane fouling in a submerged membrane bioreactor (MBR) system, but significant energy is consumed for excess air production. Therefore, an alternative strategy for membrane fouling control is currently needed. A new configuration of MBR was proposed in this study to control membrane fouling effectively. To reduce biosolids concentration near the membrane surface, the position of the membrane module in MBR was elevated from the bottom to the top in the reactor. This could divide the reactor to two different zones: upper and lower zone. Air was not supplied at the lower zone whereas aeration was given to the upper zone where the membrane filtration was carried out. Biosolids concentration was reduced in the upper zone because the mixed liquor was settled down to the lower zone. Membrane fouling could be lessened in the upper zone due to the reduced biosolids concentration. Therefore, to verify if this new configuration of MBR could mitigate membrane fouling, the effect of changing vertical position of the membrane module in MBR on membrane fouling was investigated. Prior to verification the effect of elevation of membrane module on membrane fouling, influence of MLSS concentration on membrane fouling was investigated first. Transmembrane pressure (TMP) increase became steep as MLSS concentration increased. And the immersed membrane module was elevated from the bottom to the top of the MBR. When the upper membrane was located in the bioreactor, less membrane fouling was observed. This could demonstrate a possibility of new MBR design to control membrane fouling. In addition, reduced dissolved oxygen level in the returned sludge to anoxic tank could increase denitrification efficiency if this configuration is directly applied to biological nutrient removal processes.     

Influence of Dissolved Organic Carbon and Suspension Viscosity on Membrane Fouling in Submerged Membrane Bioreactor

Abstract

This paper deals with the membrane fouling in membrane bioreactor (MBR). Based on the experimental data obtained in the MBR pilot plant study, the influence of F/M ratio on the irreversible and reversible fouling was discussed in the wide range of MLSS concentration. In the case of lower MLSS concentration (2,000–3,000 mg/L), irreversible fouling rate of membrane increased with increasing F/M ratio because of the accumulation of DOC in the mixed liquor. It seems that soluble microbial products with the similar size of the membrane pore will be most responsible for the irreversible fouling. In the case of higher MLSS concentration (8,000–12,000 mg/L), reversible fouling rate of membrane increased with increasing F/M ratio because of the increased suspension viscosity caused by the increased activated sludge size or volume even in the same MLSS concentration.     

单一反应体系曝气量与污泥质量浓度对同步硝化反硝化的影响

利用自培养硝化污泥与实验室筛选的1株反硝化细菌共培养形成共生污泥,构建膜生物反应器(MBR)单一反应体系同步硝化反硝化系统,得到系统良好同步硝化反硝化曝气量和污泥浓度的最优条件。由试验结果可知:在混合污泥质量浓度(MLSS)6.0~10.0 g/L时,调节曝气量,可以使单污泥同步硝化反硝化总氮(TN)去除率达到85%以上。不同MLSS下,达到最高TN去除率的最佳曝气量随着MLSS增高而向高曝气量偏移。随着MLSS增高,响应因子F变小,由曝气量的变化而引起的TN去除率变化明显变缓,表示MLSS对O2传递的缓冲能力越强。在MLSS为8 g/L条件下,低负荷比较容易达到较高的TN去除率,而高负荷下需要更高的曝气量以获得高的TN去除率,系统适合的NH4+-N负荷范围0~0.30 kg/(m3.d)。MLSS≥3.0 g/L,出水化学需氧量(COD)低于50 mg/L,COD大部分贡献于反硝化所需C源。单一反应体系同步硝化反硝化系统能对负荷的改变作出及时的回应,整体上运行比较稳定。     

Experimental study on application of the boundary layer theory for estimating steady aeration intensity of precoated dynamic membrane bioreactors

This paper introduced an approach that used precoated dynamic membrane (PDM) formed from powder activated carbon (PAC) on common terylene filter cloth instead of the conventional MF/UF membrane to build a membrane bioreactor (MBR) for wastewater treatment. The influence of aeration intensity for the PDM stability and the performance of the precoated dynamic membrane bioreactor (PDMBR) for treating municipal wastewater were investigated. The results of the rheological behavior of activated sludge in MBR showed that this liquor was approximated to Newtonian fluid while MLSS was less than 8100 mg/L. From the view of the mechanism of PDM formation process, when the thickness of laminar flow boundary layer was equal to that of PDM, PDMBR would run steadily, and this aeration intensity was defined as steady aeration intensity (172 L/h), which was estimated through using the boundary layer theory in the Newtonian hydrodynamics. In order to confirm the validity of theoretical calculation according to the flat membrane boundary layer theory, transmembrane pressure and treatment performance were observed when aeration intensity by gradual regulation began with oxygen supply aeration intensity (3–5 mg/L), increased up to theoretical calculation results, then till PDM detached. During PDMBR steadily running (31 days), effluent COD was less than 12.5 mg/L and its average removal efficiency was 97.5%, NH₄⁺–N was less than 5.3 mg/L and its average removal efficiency was 76.1%, while the transmembrane pressure just increased to 27 KPa. The results indicated that this operational mode could enhance the stability of PDMBR. During the late period, aeration intensity in practice in the range of 190–200 L/h was obtained. The experimental results concluded that application of the boundary layer theory in aeration intensity theoretical calculation was valid.     

膜生物反应器中影响膜透水率的几个因素

本文研究了影响膜 -好氧生物反应器中中空纤维膜透水率的几个因素 ,如组件长度、操作压力、膜面流速、活性污泥浓度和温度。中空纤维膜内 ,压力沿料液流动方向呈抛物线型分布 ,所以在膜内径和膜面流速一定的情况下 ,存在一个最佳的膜组件长度 Llin使得膜利用率最高 ,且最省能 ;操作压力对膜透水率的影响分为三个区域 ,各个区域膜的主要过滤阻力不同 ,不同污泥浓度时 ,为了使中空纤维膜内腔不堵塞 ,膜面流速必须高于某一范围 ,膜透水率随温度呈正比例关系变化。     

A Novel Sponge‐Submerged Membrane Bioreactor (SSMBR) for Wastewater Treatment and Reuse

Abstract

Membrane fouling has been regarded as one of the biggest challenges to widespread application of membrane bioreactor (MBR). This study focuses on minimizing the membrane fouling and improving the performance of submerged membrane bioreactor (SMBR) by porous sponge addition. The effects of sponge addition on sustainable flux and membrane fouling were investigated. Acclimatized sponge could significantly increase the suspended growth in SMBR with biomass of 16.7 g/L_(sponge). With the sponge volume fraction of 10%, SSMBR could enhance sustainable flux up to 50 L/m² · h compared with sustainable flux of SMBR (only 25 L/m² · h). SSMBR also exhibited excellent results in terms of DOC removal (over 95%), COD removal (over 97%), lower transmembrane pressure development, and oxygen uptake rate. Over 89% of NH₄‐N and 98% of PO₄‐P were removed when SSMBR was operated with a MLSS concentration of 15 g/L.