Decentralized wastewater system practices in developing countries: A systematic review

Decentralized wastewater systems (DWWSs) are an alternative to the ever-expanding sanitation problems in developing countries. This systematic review aims to identify the decentralized wastewater management system practices in developing countries. The PRISMA methodology and the archival research methods were used to identify papers published in the last 20 years through Scopus and Google Scholar. The results showed that about 45% of the studies conducted performance analyses of different types of decentralized wastewater systems, indicating a relatively average rate of practice and implementation of decentralization in various developing countries, even though there are constraints that hinder the adoption of the systems.     

浸没式膜—生物反应器处理市政废水试验研究

通过浸没式膜—生物反应器处理市政废水的小试试验,考察了系统的处理效果、污泥特性、膜污染特性及清洗效果,结果表明:SMBR的高效截留作用可弥补生物处理单元的不稳定性,相比CAS工艺对市政废水有更好的处理效果。     

电絮凝深度处理焦化废水的研究

探讨了电絮凝法深度处理焦化废水的工艺,采用特制的电絮凝反应器,系统考查了电流强度、反应时间、pH值和极板间距等因素对电絮凝效果的影响,试验结果表明,电絮凝工艺对焦化废水的NH3-N和COD均有很好的处理效果,是一种前景广阔的深度处理工艺。     

Combination of Advanced Oxidation Processes and biological treatments for wastewater decontamination--a review

Nowadays there is a continuously increasing worldwide concern for development of alternative water reuse technologies, mainly focused on agriculture and industry. In this context, Advanced Oxidation Processes (AOPs) are considered a highly competitive water treatment technology for the removal of those organic pollutants not treatable by conventional techniques due to their high chemical stability and/or low biodegradability. Although chemical oxidation for complete mineralization is usually expensive, its combination with a biological treatment is widely reported to reduce operating costs. This paper reviews recent research combining AOPs (as a pre-treatment or post-treatment stage) and bioremediation technologies for the decontamination of a wide range of synthetic and real industrial wastewater. Special emphasis is also placed on recent studies and large-scale combination schemes developed in Mediterranean countries for non-biodegradable wastewater treatment and reuse. The main conclusions arrived at from the overall assessment of the literature are that more work needs to be done on degradation kinetics and reactor modeling of the combined process, and also dynamics of the initial attack on primary contaminants and intermediate species generation. Furthermore, better economic models must be developed to estimate how the cost of this combined process varies with specific industrial wastewater characteristics, the overall decontamination efficiency and the relative cost of the AOP versus biological treatment.     

Nutrient recovery and crop yield enhancement in irrigation with reclaimed wastewater: a case study

The paper reports results of treated wastewater reuse field experiments carried out in Apulia (Southern Italy). Fennel and lettuce were irrigated with four different water sources: three reclaimed wastewater streams, obtained by applying different treatment schemes to the same municipal wastewater, and a conventional source (well water). Differences between the three effluents were significant in terms of suspended solids and faecal indicators. Both lettuce and fennel yields were enhanced by the high content of nutrients in the effluent of one of the treatment plants, which had been operated for partial nitrogen removal. In particular, fennel productivity was enhanced by replacing chemical fertirrigation with the supply of nutrients contained in the irrigation water.     

污水百乐克工艺设计及特点

介绍了河北省武安市污水处理厂的百乐克系统工艺实际情况,涉及到工艺池设计尺寸、功能、运行参数、设备选型及工艺设计特点等内容,对其他同类污水处理厂具有一定指导作用。     

Comparison of UV-Cl and UV-H2O2 advanced oxidation processes in the degradation of contaminants from water and wastewater: A review

Applications of advanced oxidation processes (AOPs) in water and wastewater treatment have been the subject of growing interest throughout the last decade. Although UV/hydrogen peroxide (UV-H₂O₂) is the most established technology among the UV-AOPs, UV-chlorine (UV-Cl) is emerging as a reliable and potentially more cost-effective alternative. Recent studies have indicated that UV-Cl processes may be more efficient and economically favourable for the degradation of some chemicals of emerging concern from contaminated water. Moreover, in terms of the formation of disinfection by-products (DBPs), UV-H₂O₂ seems to have no superiority over UV-Cl. This said, more investigation in the assessment of genotoxicity and cytotoxicity of DBPs is required. Additionally, more pilot-scale and full-scale studies are required to establish UV-Cl as a reliable alternative to UV- H₂O₂. This paper compares UV-Cl and UV-H₂O₂ AOPs for the degradation of intractable chemicals from water and wastewater based on the practical considerations of efficiency, cost, DBP formation, kinetics and sensitivity to water matrix variability. Finally, various modelling approaches to UV-Cl have been reviewed. This review showed that UV-Cl is superior to UV-H₂O₂ in terms of degradation efficiency and cost effectiveness and can be a robust alternative in many UV-AOPs applications.     

Treatment of organic pollution in industrial saline wastewater: a literature review

Many industrial sectors are likely to generate highly saline wastewater: these include the agro-food, petroleum and leather industries. The discharge of such wastewater containing at the same time high salinity and high organic content without prior treatment is known to adversely affect the aquatic life, water potability and agriculture. Thus, legislation is becoming more stringent and the treatment of saline wastewater, both for organic matter and salt removal, is nowadays compulsory in many countries. Saline effluents are conventionally treated through physico-chemical means, as biological treatment is strongly inhibited by salts (mainly NaCl). However, the costs of physico-chemical treatments being particularly high, alternative systems for the treatment of organic matter are nowadays increasingly the focus of research. Most of such systems involve anaerobic or aerobic biological treatment. Even though biological treatment of carbonaceous, nitrogenous and phosphorous pollution has proved to be feasible at high salt concentrations, the performance obtained depends on a proper adaptation of the biomass or the use of halophilic organisms. Another major limit is related to the turbidity problems inherent in saline effluents. For this reason, the major need for research in the future will be the combination of physico-chemical/biological treatment of saline industrial effluents, with regard to the global treatment chain, in order to meet the regulations.     

城市污水回用深度处理方法及其研究进展

介绍了城市污水回用深度处理的概念,总结了几种常见的城市污水回用深度处理方法,对它们的原理和特点进行了简单概述,并阐述了近年来这些深度处理方法的研究进展,从而使城市污水作为新的资源得以循环利用,提高了城市资源的利用率。     

Crossflow electro-microfiltration of oxide-CMP wastewater

In this work, an electrically enhanced crossflow microfiltration (EECMF) system was used for the treatment of oxide-CMP wastewater under different operating conditions to investigate their effects on filtration rate. Oxide-CMP wastewater was obtained from a wafer fab and characterized by various standard methods. A membrane with a cut size of 0.1microm was used in the EECMF system. Operating parameters studied include crossflow velocity, transmembrane pressure, mode of electric field, electric field strength, and mode of backwashing. The filtration rate was found to increase with increasing crossflow velocity, electric field strength, and transmembrane pressure when operated below the critical electric field strength. Experimental results indicated that intra-filtration-run backwashing outperformed inter-filtration-run backwashing in terms of filtration rate. Experimental results also showed that the filtration rate for pulsed mode operation was greater than that of no electric field application, but worse than that of continuous mode operation. Using the present EECMF system, a fairly good quality of filtrate was obtained. It was found that the filtrate having a turbidity of 0.39 NTU is achievable. Thus, the filtrate could be reused for non-process applications.     

回用水系统实际运行中出现的问题及其对策

针对郑州市五龙口污水处理厂回用水系统实际运行过程中存在的加药装置堵塞、沉淀池浮泥较多、反冲洗水泵容易进气、表面扫洗作用失效、漂浮物富集、藻类大量繁殖等问题,分析了其各自产生的原因,并提出了相应的对策.通过简化投药方式、连续排泥、堵塞连通孔、抬高表面扫洗管嘴、排出浮渣、调整消毒剂量等措施使问题得到了有效的解决.     

Aerobic treatment of concentrated wastewater in a submerged bed reactor

The performance of an aerobic submerged bed reactor applied to the treatment of a concentrated effluent was assessed. The wastewater employed was diluted stillage of alcohol distilleries, presenting a COD content of 3000–3500 mg l⁻¹. The reactor was continuously operated during 200 days, corresponding to five residence times varying from 23 to 4.5 h. The results show that 60–80% of COD removal may be obtained with 10–16 h of residence time. The advantages of this type of reactor are pointed out and suggestions of improvement are also presented.     

The impact of wastewater irrigation on the chemical quality of groundwater

The purpose of this investigation was to assess the groundwater impact of irrigation with industrial wastewater (baker's yeast wastewater, BYW) and to determine if agricultural reuse can be considered as an efficient wastewater treatment method. The impact of the irrigation and the status of the groundwater quality were determined using chemical parameters that are typical contaminants of BYW and characterise the content of total suspended solids (TSSs), organic matter (biochemical and chemical oxygen demands), nutrients (N_org, N‐NH₄, N‐NO₃, N_total, P_total and K), salts (Cl, SO₄ and Na) and pH. The study revealed that BYW irrigation did not cause a significant increase in the content of these parameters in groundwater at a low water table region (WTR). However, at a high WTR, the irrigation had an extremely significant (P < 0.001) impact on the chemical status of groundwater that has been demonstrated by substantially high values of COD, N‐NH₄, Cl, SO₄ and Na.     

污水处理原理和技术

结合污水处理工程的现状,提出了污水处理的方法,探讨了生物化学处理的原理和影响因素,分析了生物化学处理法在运行过程中出现的故障,详细介绍了利用生物化学原理的污水处理技术,以做好城市污水处理工作。     

气提升交替环流符合滤料滤池污水处理工艺的应用

介绍了气提升交替循环流复合滤料滤池的基本结构、工作原理及工艺特点,并将其应用于马鞍山市中心医院污水处理.运行结果表明,污水经该工艺处理后,CODcr、BOD5、SS及氨氮的平均去除率分别达到82.80％,88.64％,67.84％和93.72％,粪大肠菌群的灭活率在99.99％以上,且耐冲击负荷能力强,运行稳定,是一种...     

Battery industry wastewater: Pb removal and produced sludge

The process of neutralization with NaOH, in the presence of Fe(III) salt, of sulphuric acid battery industry wastewater seems to be more suitable than any other process for Pb removal because at the same time, it allows the exploitation of the scavenger action of Fe(III), which is often present in the same wastewater and precipitates as hydroxides. In order to optimize sludge production, a laboratory research study has been carried out to minimize the quantity of Fe(III) to be added. All aspects concerning the chemistry of wastewater have been taken into consideration step by step and discussed. As a result, a process which requires the addition of Fe(III) so that an Fe/Pb ratio, both expressed as ppm, of the order of 0.5 is achieved. The process has been applied to two artificial solutions, characterized by a content of H₂SO₄ of 1000 and 5000 ppm, respectively, and by 10 ppm of Pb, as well as to five samples of wastewater. The proposed process takes about 1 h to perform: 30 min for neutralization up to pH 8.5–9.5 and Fe(III) addition and 30 min for correction in the 9–9.5 pH range and for flocculation with the help of a polyelectrolyte. The Pb concentration of the treated effluent is below 0.2 ppm. Conditions for Pb removal using only NaOH or Na₂CO₃ have also been considered.     

电厂脱硫除尘废水处理技术的研究及应用

介绍了电厂石灰石湿法脱硫废水的产生过程、排放情况及主要污染物,论述了国内外脱硫废水处理的技术和发展趋势,并结合工程实例,给出了脱硫废水处理技术在电厂锅炉废水处理中的应用。     

Fuzzy control of disturbances in a wastewater treatment process

This paper describes a real-time process control scheme to cope with the problem of input disturbances in wastewater treatment processes, based on a fuzzy inferential control system. This can detect the presence of a dangerous input conditions whenever either organic overload or inhibitory/toxic compounds are present in the raw wastewater. Based on this diagnosis, a set of fuzzy rules are implemented to divert the process flow and bring the system back into a safe state. The control system was designed and tested using a pilot plant, to which a toxic disturbance was applied. Its behaviour with and without fuzzy control are compared, and the process reliability improvement in the controlled case is demonstrated.     

辅助曝气式新型人工湿地模型处理污水的研究

人工湿地系统具有投资少、运行费用低、管理简单、处理效果稳定、便于就地回用等特点.在人工湿地的基础上增加曝气装置,推动了系统对COD的去除作用以及氨氮的硝化作用.研究表明,在进水COD为324mg/L、NH4＋-N为34mg/L的条件下,出水平均浓度分别为25,3.8mg/L,达到了国家一级A标准.     

UASB-SBR工艺处理玉米淀粉生产废水

介绍了玉米淀粉废水的特点，阐述了UASB-SBR工艺处理玉米淀粉废水的工艺流程，经工程实际运行表明，可稳定达到国家二级排放标准，同时获得了显著的经济效益。