【作者】 张业健；

【导师】 张振家；

【作者基本信息】 上海交通大学 ， 环境工程， 2008， 博士

【摘要】 油棕是一种高产热带油料作物,主产于马来西亚和印度尼西亚等地。从油棕的果实——鲜果穗中提取棕油的过程包括杀青、脱果、蒸煮、榨油、沉淀、澄清和真空干燥等工序,每加工1吨鲜果穗需水1.5 m3,其中约50%以废水形式排放。棕油生产废水(POME)呈深褐色,粘稠,具有低pH、高盐、有机物和悬浮物含量高等特征。除少量被直接施于农田灌溉和用作动物饲料外,通常采用脱水、干燥、蒸发、絮凝、气浮、超滤以及生物法等处理POME。马来西亚最常见的棕油废水处理方法是厌氧塘/兼氧塘/好氧塘工艺,约有85%的棕油生产厂采用该处理流程。但其缺点是水力停留时间(HRT)太长,一般要20 d以上,所以占地面积也大。为缩短处理所需时间,同时减少占地,研究人员提出了脱水、干燥、蒸发等物化工艺,并比较了各种新型高效厌氧反应器如厌氧滤器、厌氧流化床、厌氧折流板反应器、上流式厌氧污泥床反应器(UASB)等处理POME的实际效果。本文以马来西亚某棕油厂生产废水为研究对象,提出了产酸产甲烷一体化高效厌氧反应器(AnaEG)+好氧内循环生物膜反应器(BioAX)+超滤(UF)+反渗透(RO)的棕油废水处理及零排放新工艺,通过对处理系统中各单元过程的独立研究和联合运行测试,对所提出的新工艺作出全面评价。论文主要分四大部分:⑴AnaEG反应器启动和运行;⑵BioAX反应器启动和运行;⑶好氧出水的脱色研究,包括混凝脱色和吸附脱色;⑷厌氧+好氧+膜分离工艺联合运行。本研究主要结论如下:在起初150 d的运行期间内,AnaEG反应器进水COD从5000 mg/L逐步提升到35000 mg/L,反应器中pH一直稳定在6.98-7.53范围内,未发现VFA积累现象,出水COD始终低于2500 mg/L,平均COD去除率高达92.5%,表明厌氧反应器在转化POME中的有机物方面具有很高的效率;厌氧颗粒污泥的活性较好,平均产甲烷活性为0.488 gCOD CH4/(gVSS·d);产气中甲烷含量约为70%;厌氧出水VFA以乙酸为主,占总VFA的2/3以上。BioAX反应器在进水COD和SS分别为6000和1758 mg/L条件下,出水浓度分别为4532和476 mg/L,去除率分别为19%和73%;出水中未检出NH3-N。好氧出水的脱色实验结果:(1)絮凝剂FeCl3:最佳投药量为500 mg/L,pH对色度去除影响甚微,色度去除率为40%;(2)絮凝剂PAC:最佳投药量为700 mg/L,最佳pH为5.0,色度去除率高达90%;(3)絮凝剂FeSO4:最佳投药量为800 mg/L,最佳pH为10.0,色度去除率91%;(4)粉末活性炭最佳投加量为20 mg/L,最佳吸附时间为30 min,最佳pH为6.0,色度去除率91%。AnaEG+BioAX+UF+RO联合工艺处理POME结果表明,UF单元对浊度和色度的去除率比较高,分别达到了96.4%和68.8%,但是对其他四项指标(COD、TOC、BOD5和电导率)去除效果不明显; COD、TOC、BOD5和电导率等指标的降低主要是在RO单元完成的,去除率分别达到了97.1%、99.3%、90.6%和93.4%;经过UF+RO处理后,好氧出水中全部有机物和绝大部分盐分已被去除,产水无色透明;参比工业锅炉水质标准发现,RO产水需经软化处理才能满足锅炉补给水水质要求。UF+RO膜清洗方法:首先清水正冲,冲刷去残留在膜单元中的POME废水;然后用含1%(w/w)NaOH和0.6%(w/w)NaClO的化学清洗液清洗25 min;最后用清水再次对膜单元进行清洗,直至出水pH呈中性,清洗后UF和RO的通量恢复率分别为95.3%和91.7%。更多还原

【Abstract】 Oil palm (elaeis guineensis) is one of the most versatile crops in the tropical region, notably in Malaysia and Indonesia. The extraction of palm oil from the fruit of elaeis guineensis involves a number of processing procedures: sterilization、stripping、digestion、pressing、classification、purification and vacuum drying. In the extraction process, large quantities of water are required. It is estimated that about 1.5 m3 of water are needed to process one ton of fresh fruit bunch (FFB), half of this amount ends up as palm oil mill effluent (POME). The raw POME is a thick brown liquid and characterized by low pH、high biological and chemical oxygen demand、high salt and suspended solids. As a result, the discharge of palm oil mill effluent has the potential to severely pollute the receiving waterways.Besides immediate utilization such as crop irrigation and using as animal fodder, many methods have been developed to control POME pollution, including decanting and drying、evaporation、coagulation、flotation、ultrafiltration and various aerobic and anaerobic biodegradation technologies. Today about 85% of POME treatment is based on anaerobic/facultative/aerobic pond system by Malaysian palm oil mills, which is characterized by long hydraulic retention time (HRT), often in an excess of 20 days, necessitating large areas of land or digesters. To shorten the treatment time, lessen the land required, besides physico-chemical methods such as decanting and drying, evaporation, coagulation, high rate reactors such as anaerobic filter, anaerobic fluidized bed reactor, anaerobic baffled reactor, UASB and other hybrid reactors are put forward and evaluated in treating POME. In the paper, palm oil mill effluent (POME) from Sungal Burung palm oil mill in Malaysia was treated by a technical flow combined by AnaEG+BioAX+UF+RO, after the foundation research on each step in the system, the performance of the overall sequential system was evaluated. The paper can be divided into four parts:⑴startup and operation of AnaEG reactor;⑵startup and operation of aerobic inner-circulation biofilm reactor——BioAX;⑶decoloring treatment of discharge from aerobic reactor, including coagulation and adsorption decoloring;⑷combination operation of the overall treating system. The main results are listed below:During the 150 days’start-up duration, influent COD of AnaEG was increased stepwise from 5000 to 35000 mg/L, pH in reactor was stable which was in the range of 6.98-7.53, VFA accumulation was not happened, effluent COD was less than 2500 mg/L all the while, the average COD removal efficiency was as high as 92.5%, indicating that AnaEG was in good condition in digesting and transforming the organic compound in POME; the activity of anaerobic granular sludge was good, and the average methane producing activity was 0.488 gCOD/(gVSS·d); methane content in biogas produced was 70% (n/n), acetic acid was the main VFA in effluent from AnaEG, about 2/3 of the total VFA.When aerobic biofilm reactor——BioAX was in steady-state during operation stage, influent COD concentration was 6000 mg/L, pH in reactor was 8.4-8.8, salts concentration was 6000-8000 mg/L, the average removal efficiency of COD and SS was 19.07%, respectively, no NH3-N was detected in the aerobic effluent.Decolorizing experimental results of aerobic effluent by coagulation and adsorption: (1) flocculant FeCl3: the optimum dosage was 500 mg/L, pH had no influence on color removal, and the optimal color removal rate was 40%; (2) flocculant PAC: the optimum dosage and pH were 700 mg/L and 5.0, respectively, and the optimal color removal rate was 90%; (3) flocculant FeSO4: the optimum dosage and pH were 800 mg/L and 10.0, respectively, and the optimal color removal efficiency was 91%; (4) Results got from adsorption using powdered activated carbon indicated that the optimum dosage、adsorption time and pH were 20 mg/L、30 min and 6.0, respectively, and the optimal color removal rate was 91%.Experimental results of combination operation of the overall treating system---AnaEG+BioAX+UF+RO: UF membrane was very efficient in removing turbidity and color from aerobic effluent, the removal efficiency were 96.4% and 68.8%, respectively, but it exhibited inefficient in removing COD、TOC、BOD and electrical conductivity, they were mainly got rid of by RO membrane, and the removal rate were 97.1%、99.3%、90.6% and 93.4%, respectively; After filtrated by UF and RO membrane, all organic compound and most of the salts were removed from aerobic effluent, and RO permeate was colorless and transparent. Further comparison of the characteristics of RO permeate with the boiler feed water standard indicated that the RO permeate should be softened before it was to be used as the boiler feed water.Membrane cleaning: the membrane were first circulated with clean water to flush out POME remaining in membranes, and then circulated with chemical solution mixed by 1% (w/w) NaOH and 0.6% (w/w) NaClO for 25 min, finally, the membrane rinsed again with clean water until a neutral pH was achieved. The flux after cleaning was 95.3% and 91.7% of the initial flux value for the UF and RO, respectively.更多还原