重力分离—NMC工艺处理对二氯苯生产废水

采用重力分离－ＮＭＣ（中和、混凝、吹脱）工艺处理对二氯苯生产废水，对工艺条件进行了选择试验，选定的最佳工艺条件为：废水静置分层时间５０－６０ｍｉｎ，中和至ＰＨ７，ＰＡＭ投加量５０－７５ｍｇ／Ｌ，空气流量１０ｌ／ｍｉｎ，反应温度５０－５５℃；反应时间６０ｍｉｎ。废水经处理后，苯和氯苯浓度可分别降至１．００ｍｇ／Ｌ和１．１０ｍｇ／Ｌ且可回收９０％以上的苯和氯苯。     

硫酸生产中废水治理工艺的改进

采用ＮａＣｌＯ氧化共沉淀脱砷工艺处理硫酸废水，在ＮａＣｌＯ投加量１２００ｍｇ／Ｌ、铁砷比３．０、氧化终点ｐＨ３．５、聚丙烯酰胺投加量１５ｍｇ／Ｌ的条件下，处理后出水中砷含量降至１．０６ｍｇ／Ｌ，再经第二级中和沉淀后可达国家排放标准。此工艺能使砷富集于沉渣中，达到可回收的水平，此外还可大大减少含砷废渣的产生量。     

缩合－电解法处理苯胺废水

采用缩合－电解法处理苯胺废水，缩合过程的最佳ｐＨ为５．０—６．０，甲醛的最佳投加量视废水中苯胺含量而定；电解过程中，ＮａＣｌ的最佳投加量为３％（ｗｔ），控制电解液ｐＨ为５．０—７．０、电解时间１２０—１４０ｍｉｎ、槽电压３Ｖ、电流密度０．９Ａ／ｄｍ￣２。在上述条件下，苯胺含量为１０００—１００００ｍｇ／Ｌ的废水经缩合－电解法处理后，ＣＯＤ＜２５０ｍｇ／Ｌ，苯胺＜０．１ｍｇ／Ｌ。     

氯氰菊酯废水物化和生化处理的研究

对氯氰菊酯生产废水进行了物化预处理和生化处理试验,物化预处理工艺路线为高温高压氧化法,最佳温度为２２０℃,对庆压力为３．５４ＭＰａ,最佳时间为１ｈ。废水经预处理后,ＣＯＤ从４３１００ｍｇ／Ｌ降至１７３００ｍｇ／Ｌ,去除率为６０％;氰含量从３６４０ｍｇ／ＫＬ降至小于１ｍｇ／Ｌ,去除率高达９９．９％;出水ＢＯＤ５／ＣＯＤ上升至０．３４。     

炼油废水生物脱氮中间试验

对炼油废水中氮氮的生物降解用两种工艺进行了中间试验。试验结果表明,正常工艺条件下,Ｏ／Ｏ工艺处理后出水中ＮＨ３－Ｎ〈２５ｍｇ／Ｌ,ＣＯＤ〈４０ｍｇ／Ｌ,油〈５ｍｇ／Ｌ;Ａ／Ｏ工艺处理后出水中ＮＨ３－Ｎ〈２０ｍｇ／Ｌ,ＣＯＤ〈５０ｍｇ／Ｌ,油〈５ｍｇ／Ｌ,ＮＯ＾３－Ｎ〈１０ｍｇ／Ｌ。     

缩合—电解法处理苯胺废水

采用缩合－电解法处理苯胺废水，缩合过程的最佳ＰＨ为５．０－６．０，甲醛的最佳投加量视废水中苯胺含量而定；电解过程中，ＮａＣｌ的最佳投加量为３％（ｗｔ），控制电解液ＰＨ为５．０－７．０、电解时间１２０－１４０ｍｉｎ、槽电压３Ｖ、电流密度０．９Ａ／ｄｍ＾２。在上述条件下，苯胺含量为１０００－１００００ｍｇ／Ｌ的废水经缩合－电解法处理后，ＣＯＤ＜２５０ｍｇ／Ｌ，苯胺＜０．１ｍｇ／Ｌ。     

流态化电极电解法处理含氰废水

采用细粒膨胀石墨流态化阳极电解法处理含氰量为８０－９０ｍｇ／Ｌ的废水，试验选择出的处理条件为：ｐＨ９－１０，废水流速４２－４５Ｌ／ｈ，槽电流２－３Ａ，ＮａＣｌ加入量１．５－３．０ｇ／Ｌ。同样条件下，使用细粒膨胀石墨流态化电极的电解除氰效果较用简形板状电极好。     

硫脲法浸出回收炼锌废渣中的银

对用硫脲法从炼锌废渣中浸出回收银的工艺及其影响因素进行了研究;确定了最佳浸出工艺条件为：硫脲质量浓度１０ｇ／Ｌ,「Ｆｅ＾３＋」０．０１２５ｍｇ／Ｌ,液固比１０：１,浸出液ＰＨ１．５－２．０,浸出温度４０－６０℃;     

碱性和弱酸性染料混合废水处理方法

采用“中和－氯氧化－电化学反应－催化氧化”组合工艺处理碱性、弱酸性染料混合废水,可使混合废水的ＣＯＤ由１４５６０ｍｇ／Ｌ降至２１５ｍｇ／Ｌ,色度由５０００倍降至１０倍以下。试验结果表明,不同染料废水混合后可发生沉淀效应,若组合得当,可使染普废得到很大程度的净化;ＣｌＯ２对某些染料废水具有良好的去除ＣＯＤ和脱色作用。     

化肥厂含氮废水的生物硝化处理试验

用维纶软性纤维作填料，进行了生物膜法三级硝化处理化肥厂含氮废水的试验，ＴＫＮ的去除负荷最高可达０．３７７ｋｇ／ｍ＾３．ｄ，总硝化率可达９３％。三级硝化后，出水中Ｕｒｅａ－Ｎ〈３ｍｇ／Ｌ、ＮＨ３－Ｎ〈１７ｍｇ／Ｌ。若投加痕量Ｍｇ＾２（５０μｇ／Ｌ）可以促进尿素的水解 。     

Behavior of As,Cd, Co,Cr, Cu,Pb, Ni,and Zn at the soil/plant interface around an uncontrolled landfill (Casablanca,Morocco)

The present work undertaken in the environmental context aims to study the distribution of heavy metals in plants that grow naturally around uncontrolled landfills. The study's goal was to identify plants that can be used to remediate contaminated soils. For this purpose, 14 plants species and their rhizospheric soil samples were collected and analyzed for arsenic, cadmium, cobalt, chromium, copper, lead, nickel, and zinc by inductively coupled plasma‐atomic emission spectrometry. The results showed the presence of elevated metal concentrations in soil, many exceeding the regulatory values, and that many species exhibited an ability to accumulate multiple metals in their shoots and roots without sustaining toxicity. This was confirmed by bioconcentration and translocation factors generally higher than 1.     

Clay, Phosphate Adsorption, Dispersion, and Rheology

Soluble phosphate is a common ingredient of fertilizer used in agriculture production all over the world. This chemical mixed with soil is transported into the water and marine environment via rainfall causing a range of environmental problems such as toxic algae bloom. Kaolin clay is a common material found in soil and is used as a model system to understand the effects of phosphate adsorption on the flocculation/dispersion of the clay slurries. In the topics, torrential downpours are common. The large water flow will easily disperse the unflocculated or weakly flocculated sediments over a wide area including river and marine environments. Phosphate adsorption was found to weaken the interparticle forces between clay platelets in the slurries. At high enough concentration, it will completely deflocculate the clay slurries, i.e. the net interparticle force is repulsive. A deflocculated slurry is characterised by a low viscosity and no yield stress. As a result, it is much easier to disperse this slurry over a wide area possible even in a small downpour. This study will present the flow and yield stress behaviour of kaolin clay slurries under the influence of adsorbed phosphate.     

Inventory of twenty-six combustible wastes as sources of potentially toxic elements: B,Cr, Cu,Zn, As,Sb, Ba,and Pb

Journal of Material Cycles and Waste Management - Municipal solid waste (MSW) is converted to various materials through treatment processes, which in turn distributes potentially toxic elements...     

Trends in Fish Community Structure,Biomass, and Production in Three Algoma,Ontario, Lakes

Long-term (i.e. >10 years) whole community fish dataincluding catch-per-unit-effort, abundance, biomass, andproduction from three lakes were used: 1) to examine variabilityin fish population and community measures among years using wholelake assessments of fish populations derived from mark recaptureexperiments, 2) to assess implications arising from monitoringindividual species vs. the whole fish community, and 3) toascertain whether, in fisheries assessments (science) a commonlyused surrogate measure, [catch-per-unit-effort (CPUE)] reflectedannual changes in the fish assemblage, and thus may be a goodestimator of abundance. High, long-term variability was evident in the abundance andbiomass of a fish species in our lakes, yet the communityremained relatively stable in terms of its biomass andproduction. Changes in total fish community biomass appear drivenby large species, which, relative to small fish species, remainstable among years. Among years, species richness remainedstable; however, fish species changed in the community. AnnualCPUE was found to be a suitable surrogate for abundance (N) ofsmall fishes; CPUE x mean weight of the catch (bCPUE) was asuitable surrogate for biomass (B) of large fishes. Prior toconcluding that a change in a fish population has occurred as aresult of a stressor, care must be taken to critically examinethe level of population assessment in order to avoid acceptingpotentially invalid conclusions.     

Behaviour of Cd,Cr, Mn,Ni, Pb,and Zn in sewage sludge incineration by fluidised bed furnace

Cd, Cr, Mn, Ni, Pb, and Zn behaviour during sewage sludge incineration was investigated in seven pilot tests using a circulating fluidised bed furnace. Dewatered sludge at a solids concentration of 15-18% was fed to the furnace either alone (two tests) or spiked with chlorinated organic compounds (five tests). The behaviour of metals in the fluidised bed furnace was studied by comparing metal concentrations in the two main ash streams: ash separated from the cyclone immediately following the fluidised bed furnace, and fly ash recovered in the final bag filter. A metal enrichment factor was defined as the ratio of metal concentration between filter ash and cyclone ash. Only Cd and Pb showed any significant enrichment. Their enrichment factors were mainly affected by chlorine concentration in the feed sludge. To check whether simple equilibrium models may explain and predict metal behaviour, experimental data were compared with percentage of the metal vaporisation in the combustion chamber predicted using a thermodynamic model. Discrepancies between model predictions and experimental results are accounted for by considering that kinetics may be a limiting factor in the formation of metal chloride gaseous species. Due to the very short sludge residence time in the fluidised bed furnace, the gaseous compounds have little chance to evolve completely.     

Waste incineration,PVC, and dioxins

Waste incineration is becoming increasingly necessary to tackle the rapidly rising amounts of municipal solid waste (MSW); in China many large cities are already surrounded by a girdle of landfills. Still, the not-in-my-backyard (nimby) syndrome holds strong. This attitude stems from fear of dioxins. These have been associated with incineration (‘dioxin factories’) and at times also with polyvinylchloride. In this paper this issue is analysed. China should build additional trust in MSW incineration, following promulgation of stricter emission standards, enforced by stringent controls.