城市污水COD深度降解技术研究

为了对经过生物处理后COD仍不能达标排放的含不饱和有机化合物的城市污水进行深度降解,采用高纯二氧化氯和复合二氧化氯对该类污水进行选择性氧化,试验结果和工程案例表明:采用高纯二氧化氯处理试验污水时,30mg/L的投加量,常温条件下反应30min,可使污水的COD从87mg/L降到50mg/L以下;采用复合二氧化氯处理试验污水时,10-50mg/L的投加量,常温条件下反应30min,对于去除COD效果并不明显,且去除率在10%以下。经济技术评估表明,采用生物处理和选择性氧化处理组合工艺来处理不饱和有机化合物含量较高的城市污水,有广阔应用前景。     

内循环生物流化床处理生活污水的实验研究

本技术采用自制的内循环生物流化床处理生活污水,以活性炭为载体进行挂膜实验。设备运行稳定后,通过控制进水流量和进气量,分析其对COD去除率的影响。实验结果表明:改进的快速排泥法可以保证内循环生物流化床的快速启动。在选择的实验条件下,当处理的生活污水COD值为300-600mg/L时,出水COD小于60mg/L,去除率为88.91%,达到生活污水排放标准GB18918-2002一级B排放标准。     

污水处理厂A~2/O生化法+物化法工艺设计

A~2/O生化法、物化法是污水处理中较常用的技术,其在污染物质脱出和水质净化过程中具有突出作用。为实现污水处理厂工业污水的高效处理,该文以某污水处理厂扩建工程为例,设计使用A~2/O生化法+物化法工艺进行污水净化处理,在实际处理中,强化工艺与水质管理,设计主要构筑物及相关参数,通过该工艺降低了污水处理成本,有效去除污水中的COD、TP、TN、NH_3-N成分,提升污水净化处理质量。     

城镇污水处理厂生物化学强化除磷方法的研究

八钢生活污水处理厂采用CASS工艺对城镇污水进行处理,该文考察了城镇污水处理系统在气温较低及进水水质超设计值时的生物化学强化除磷规律,分析了生物化学强化除磷和对出水水质的影响。研究结果 :进水总磷为7.2 mg/L～12.7 mg/L时,气温小于-10℃时,原设计除磷工艺出水总磷为2.1 mg/L～4.5 mg/L。采用生物化学强化除磷的方法可将出水总磷降至0.5 mg/L～0.9 mg/L,还有利于进一步降低系统出水COD和SS值。     

浅析城市污水处理厂生物除臭法

本文介绍了在污水处理厂中应用的生物除臭3种方法:生物滤池法、洗涤式活性污泥法以及曝气式活性污泥法并结合案例进行分析,总结出活性污泥法是目前处理城市和工业污水普遍采用的好氧生化处理技术.其工艺流程较为简单,处理成本低,而处理效果好,BOD/COD去除率高。     

MBR-BAF系统处理辽河油田采油污水的研究

采用膜生物反应器(MBR)-曝气生物滤池(BAF)工艺处理辽河油田的采油污水,试验验证,这种处理方法可有效去除采油污水中污染物质,油、BOD5、氨氮去除率能够达到90%左右;膜生物反应器中COD容积负荷达到1.97kg/(m3·d)时,MBR-BAF系统COD平均去除率仍保持在70%以上,并具有出水清澈透明、无异味、不需投加化学药剂、不产生二次污染等优点.     

污水COD在线监测技术研究

水样中COD含量在线监测技术指的是应用特定的仪器装备针对污水内部的COD含量实施的一种在线监测的相关技术,经过各类仪器的监测工作采集到污水的各项污染情况的详细指标,为进一步付污水进行净化处理提供科学准确的参考数据。该文重点阐述了污水中COD含量在线监测领域相关解决方案的基本原理及优势,并且给出了应用过程中存在的问题,进而给出对应的改进方案并展望未来的发展趋势。     

无泡曝气膜生物反应器去除生活污水有机物的研究

以聚丙烯中空纤维作为无泡曝气膜生物反应器(MABR)生物膜载体,采用循环挂膜法进行聚丙烯中空纤维表面生物膜的培养,研制出一台小型MABR实验装置.在对生活污水的实验研究中获得了对化学需氧量(COD)和固体悬浮物(SS)良好的去除效果.研究表明:中空纤维内腔氧气压力在0.02～0.1 MPa的范围内对MABR去除COD的能力具有较小的影响;当反应器中污水的循环次数达到7.5次/h时,污水的循环流速对MABR的COD降解效果没有显著影响.在适宜的条件下,HRT为10 h时,MABR能够较容易地使污水的出水COD保持在50 mg/L以下,SS保持在15 mg/L以下.     

洗印加工的废水处理

富士胶片厂足柄工场建成了三次废水处理系统,排出污水经三次处理后COD值(化学需氧量)可由目前的25下降到4ppm,SS(净游物)可由目前的70ppm下降到7     

石油化工碱渣废水治理措施研究

炼油化工厂在加工过程中,产生和排出含污染物的工业废水,通常其COD值都特别高,可高达数十万,COD及硫化物、酚等污染物的排放量占炼油厂或石油化工污染物排放量的20％～30％,此外还含有大量的酚和环烷酸,这些物质如不妥善处理,直接排放到全厂污水系统,会给污水处理场生化系统带来很大冲击,严重影响污水处理场的正常运行,因此,必须采用行之有效的预处理方式对炼油化工厂的碱渣进行必要的预处理。     

Innovative physico-chemical treatment of wastewater incorporating Moringa oleifera seed coagulant

Moringa oleifera is a pan tropical, multipurpose tree whose seeds contain a high quality edible oil (up to 40% by weight) and water soluble proteins that act as effective coagulants for water and wastewater treatment. The use of this natural coagulant material has not yet realised its potential. A water extract of M. oleifera seed was applied to a wastewater treatment sequence comprising coagulation-flocculation-sedimentation-sand filtration. The study was laboratory based using an actual wastewater. Overall COD removals of 50% were achieved at both 50 and 100mg/l M. oleifera doses. When 50 and 100mg/l seed doses were applied in combination with 10mg/l of alum, COD removal increased to 58 and 64%, respectively. The majority of COD removal occurred during the filtration process. In the tests incorporating alum, sludge generation and filter head loss increased by factors of 3 and 2, respectively. These encouraging treatment results indicate that this may be the first treatment application that can move to large scale adoption. The simple water extract may be obtained at minimal cost from the presscake residue remaining after oil extraction from the seed. The regulatory compliance issues of adopting 'new materials' for wastewater treatment are significantly less stringent than those applying to the production of potable water.     

Combined physical,chemical and biological treatments of wastewater containing organics from a semiconductor plant

Wastewater containing organics from a semiconductor plant was experimentally investigated in this study. The wastewater is characterized by strong color, high chemical oxygen demand (COD), a large amount of refractory volatile organic compounds and low biodegradability. Because of these characteristics, treatment of this wastewater by traditional activated sludge method is essentially impossible. In the present work, combined physical, chemical and biological methods were synergistically utilized to tackle the wastewater. The combined treatment consisted of air stripping, modified Fenton oxidation and sequencing batch reactor (SBR) method. Air stripping was employed to remove the majority of volatile organic components (notably isopropyl alcohol) from the wastewater, while the Fenton treatment decomposed the remaining refractory organics leading to simultaneous reductions of wastewater COD and color. After proper dilution with other low-strength, organics-containing wastewater stream, the wastewater effluent was finally treated by the SBR method. Experimental tests were conducted to determine the effectiveness and the optimum operating conditions of each treatment process. Test results clearly demonstrated the advantages of the combined treatments. The treatment train was found capable of lowering the wastewater COD concentration from as high as 80,000 mg/l to below 100mg/l and completely eliminating the wastewater color. The overall water quality of the final effluent exceeded the direct discharge standard and the effluent can even be considered for reuse.     

Chemical and physical treatments of chemical mechanical polishing wastewater from semiconductor fabrication

Wastewater from chemical mechanical polishing (CMP) process of semiconductor fabrication was treated by physical methods. The CMP wastewater, as obtained from a large semiconductor manufacturer, was characterized by a high oxide particle content, high turbidity (NTU), and a chemical oxygen demand (COD) concentration up to 500 mg/l. Due to these characteristics, treatment of the CMP wastewater by either filtration or by traditional activated sludge method was inadequate. In the present work, physical methods consisting of chemical coagulation and reverse osmosis were employed to tackle the turbidity and COD problems. Experimental tests were conducted to assess the effectiveness of the treatment and to identify the optimum operating conditions. Test results clearly demonstrated the complementary advantages of the two methods. The treatment was capable of realizing over 99% oxide particle removal and lowering the wastewater COD to below 100 mg/l. The overall water quality of the final effluent was excellent and can be considered for reuse. Preliminary treatment of the RO retentate by ozonation was also attempted. The COD removal achieved in the ozonation was over 80% in an hour, rendering the treated RO retentate suitable for direct discharge.     

Purification of oily wastewater by ultrafiltration

Investigations have been carried out for purification of oily wastewater by a combination of ultrafiltration/reverse osmosis processes. A tubular ultrafiltration system using cellulosic and non-cellulosic membranes was tested with typical oily wastewater collected from harbour and simulated emulsion without any pretreatment. Both membrane types produced a permeate with an oil content generally less than 10 mg/dm³. Rejection of chemical oxygen demand (COD) is 80% for ultrafiltration treatment. The permeate is generally of acceptable quality for direct sewer discharge. For further treatment of UF permeate, reverse osmosis was applied with tubular B1 PCI modules using cellulose acetate membranes. The rejection of COD after ultrafiltration/reverse osmosis treatment increased up to 98.5% and total dissolved solids (TDS) to 95.7%. Reverse osmosis treatment will permit reuse of the treated water as process water.     

Energy utilization and recirculation of currant-finishing wastewater

In this study, a new method for the treatment of currant-finishing wastewater was proposed in the context of the "clean technology" concept. This method consisted of two stages. In the first stage, the currant-finishing wastewater was recirculated in the currant-wash process and in the second stage this wastewater was utilized for the production of energy through anaerobic digestion. Recycling ratios from 0 to 95% were examined. By increasing the recycling ratio, effluent's COD increased from 3808 to 43,722mg/l, effluent's BOD from 681 to 5378mg/l, total sugars from 2.57 to 42.13g/l, total phosphorous from 0.79 to 5.14mg/l and total Kjeldahl nitrogen from 7.36 to 51.9mg/l while fresh water addition decreased from 6 to 0.3kg per kg of currants processed. The optimum recycling ratio range for the wastewater energy utilization proved to be 30-40%. In this range, the mass of COD and sugars digested was maximized resulting in the highest biogas production. Thus, the proposed system could be promising since water consumption is minimized and wastewater energy utilization is achieved rendering the process almost energetically self-sufficient.     

Photoelectrocatalytic decontamination of oilfield produced wastewater containing refractory organic pollutants in the presence of high concentration of chloride ions

The feasibility study of the application of the photoelectrocatalytic decontamination of high saline produced water containing refractory organic pollutants was investigated in the slurry photoelectrocatalytic reactor with nanometer TiO2 particle prepared with sol-gel method using the acetic acid as hydrolytic catalyst. The efficiency of the photoelectrocatalytic decontamination of produced water was determined with both COD removal from the tested wastewater and the decrease of mutagenic activity evaluated by Ames tests. The experimental results showed that the photoelectrocatalysis is a quite efficient process for decontaminating the produced water, although there are high concentration of salt existed in oilfield wastewater. We found that the COD removal efficiencies by photoelectrocatalytic process are much higher than that of by photocatalytic or electrochemical oxidation individually in the photoelectrocatalytic reactor. The COD removal can be substantially improved by the added H2O2 and the generation of active chlorine from high concentration chlorides in the wastewater. The effects of various operating conditions, such as initial COD concentration, applied cell voltage, catalyst amount and initial pH value of solution, on the photoelectrocatalytic efficiencies, is also investigated in detail. The results showed that when the raw produced wastewater was diluted in a 1:1 (v/v) ratio, there is a highest COD removal efficiency. And the photoelectrocatalytic degradation of organic pollutants in saline water is much favored in acidic solution than that in neutral and/or alkaline solution.     

膜法浓缩己内酰胺废水

为研究己内酰胺生产过程中废水的膜处理条件,以巴陵石化己内酰胺生产废水为研究对象,采用反渗透膜处理工艺,在一定条件下,考察浓缩倍数对膜通量及浓缩液和透过液的水质,包括电导率、COD、pH的影响.结果表明,反渗透膜能有效地处理己内酰胺生产过程的部分废水,且水质稳定.在适宜浓缩倍数下,离子交换过程中产生的反冲洗废水的透过液水质可达到我国工业废水排放标准,聚合废水透过液也能满足生化处理要求,对于本实验采用的原料液,离子交换废水的处理控制浓缩倍数为8左右,聚合废水浓缩4～5倍较合适.     

Treatment of organophosphate-contaminated wastewater by acidic hydrolysis and precipitation

Wastewater from commercial manufacture of organophosphate (OP) pesticide of O-methyl-O-(2-isopropyl salicylate) thiophosphorusyl amide contains large amounts of organophosphate, organic sulfides, COD and NH3-N. A treatment process including acidic hydrolysis and precipitation was explored in this paper. The effects of initial pH values, hydrolysis temperature and hydrolysis time on the removal of pollutants were investigated. The experimental results showed that, in the hydrolysis, with the decreasing initial pH value, the removal of OP, sulfide and COD rose whereas the NH3-N removal declined. Increased hydrolysis temperature and time favored the removal of all the pollutants. 15.0 wt% Ca(OH)2 was sufficient for the removal of inorganic phosphorus and residual NH3-N in the precipitation step. With this chemical process, the removal of total phosphorus (TP), organophosphate, sulfides and NH3-N exceeded 90%, and the removal of COD was about 60%. The BOD5/COD value was greatly improved from 0.05 to 0.3, and the bio-degradability of the wastewater was greatly improved. The NH3 generated in the process was absorbed with water and might be reused in the manufacture of the pesticide. The results showed that this comprehensive process is effective for the treatment of this typical unbio-degradable pesticide wastewater.     

Chemical or electrochemical techniques, followed by ion exchange, for recycle of textile dye wastewater

This paper examines the use of chemical or electrocoagulation treatment process followed by ion-exchange process of the textile dye effluent. The dye effluent was treated using polymeric coagulant (cationic dye-fixing agent) or electrocoagulation (iron and aluminum electrode) process under various conditions such as various current densities and effect of pH. Efficiencies of COD reduction, colour removal and power consumption were studied for each process. The chemical or electrochemical treatment are indented primarily to remove colour and COD of wastewater while ion exchange is used to further improve the removal efficiency of the colour, COD, Fe concentration, conductivity, alkalinity and total dissolved solids (TDS). From the results chemical coagulation, maximum COD reduction of about 81.3% was obtained at 300 mg/l of coagulant whereas in electrocoagulation process, maximum COD removal of about 92.31% (0.25 A/dm2) was achieved with energy consumption of about 19.29 k Wh/kg of COD and 80% (1A/dm(2)) COD removal was obtained with energy consumption of about 130.095 k Wh/kg of COD at iron and aluminum electrodes, respectively. All the experimental results, throughout the present study, have indicated that chemical or electrocoagulation treatment followed by ion-exchange methods were very effective and were capable of elevating quality of the treated wastewater effluent to the reuse standard of the textile industry.     

Characterization and assessment of Al Ruwais refinery wastewater

An extensive bulk parameters and component-based analysis was carried out for Al Ruwais refinery wastewater during the period of June 2002-June 2003. The program included identification of major process and utilities wastewater streams and quantification of these streams relative to the total wastewater generated from all refinery processes. In addition to the high biochemical oxygen demand (BOD) and chemical oxygen demand (COD) reported levels, the analysis showed high concentrations of polyaromatic hydrocarbons (PAHs) and phenolic compounds in the major wastewater streams. Polychlorinated biphenyls (PCBs) were also detected in few streams. The caustic water was found to have the highest levels of the pollutants mentioned above. Dilution of the wastewater with process cooling water serves as the main treatment approach applied to the effluent wastewater before disposal into the sea. Primary as well as secondary treatment units are thought to be essential and strongly recommended to reduce the pollutants to levels below the United Arab Emirates (UAE) standards for marine discharge.