含砷物料制备As_2O_3的研究进展

为减少排入环境中的含砷危险固废量,寻求治理砷污染的高效方法。通过综述冶金和化工行业焙烧、烧结及熔炼等过程产生的主要以氧化物形态存在的含砷烟尘,以及净化除杂过程中产生的硫化砷渣、砷酸盐渣的提取利用研究现状,比较分析各提取方法的优势与缺陷,展望含砷物料中砷的提取与利用研究趋势,获得高效提取砷的最新工艺方法。     

Ammonium removal pathways and microbial community in GAC-sand dual media filter in drinking water treatment

A GAC-sand dual media filter (GSF) was devised as an alternative solution for drinking water treatment plant to tackle the raw water polluted by ammonium in place of expensive ozone-GAC processes or bio-pretreatments. The ammonium removal pathways and microbial community in the GSFs were investigated. The concentrations of ammonium, nitrite and nitrate nitrogen were monitored along the filter. Total inorganic nitrogen (TIN) loss occurred during the filtration. For 1 mg ammonium removal, the TIN loss was as high as 0.35 mg, DO consumption was 3.06 mg, and alkalinity consumption was 5.55 mg. It was assumed that both nitrification and denitrification processes occur in the filters to fit the TIN loss and low DO consumption. During the filtration, nitritation, nitrification and nitritation-anaerobic ammonium oxidation processes probably occur, while traditional nitrification and denitrification and simultaneous nitrification and denitrification processes may occur. In the GSFs, Nitrosomonas and Nitrospira are likely to be involved in nitrification processes, while Novosphingobium, Comamonadaceae and Oxalobacteraceae may be involved in denitrification processes.     

Control strategies for disinfection byproducts by ion exchange resin,nanofiltration and their sequential combination

● Effects of AER adsorption and NF on DBP precursors, DBPs, and TOX were examined. ● A treatment approach of resin adsorption followed by nanofiltration was developed. ● Both DOC and Br⁻ could be effectively removed by the sequential approach. ● DBPs, TOX, and cytotoxicity were significantly reduced by the sequential approach. Disinfection byproducts (DBPs) are emerging pollutants in drinking water with high health risks. Precursor reduction before disinfection is an effective strategy to control the formation of DBPs. In this study, three types of anion exchange resins (AERs) and two types of nanofiltration (NF) membranes were tested for their control effects on DBP precursors, DBPs, and total organic halogen (TOX). The results showed that, for AER adsorption, the removal efficiencies of DBP precursors, DBPs, and TOX increased with the increase of resin dose, and the strong basic macroporous anion exchange resin (M500MB) had the highest removal efficiencies. For NF, the highest removal efficiencies were achieved at an operating pressure of 4 bar, and the membrane (NF90) with a smaller molecular weight cut-off, had a better control efficiency. However, AER adsorption was inefficient in removing dissolved organic carbon (DOC); NF was inefficient in removing Br⁻ resulting in insufficient control of Br-DBPs. Accordingly, a sequential approach of AER (M500MB) adsorption followed by NF (NF90) was developed to enhance the control efficiency of DBPs. Compared with single AER adsorption and single NF, the sequential approach further increased the removal efficiencies of DOC by 19.4%–101.9%, coupled with the high Br⁻ removal efficiency of 92%, and thus improved the reduction of cyclic DBPs and TOX by 3.5%–4.9%, and 2.4%–8.4%, respectively; the sequential approach also reduced the cytotoxicity of the water sample by 66.4%.     

污泥混合基质栽培生菜重金属含量的影响因素研究

通过基质盆栽生菜试验研究污泥用量,基质容量和采收期对生菜重金属Ｚｎ、Ｎｉ含量的影响。结果表明,污泥用量与生菜重金属含量的关系因基质容量大小而变化。在小基质容量条件下,污泥用量高者重金属含量低而产量高。生菜重金属含量随采收期不同而变化。本文讨论了上述结果的原因及其在生产、科研中的重要性。     

半导体材料生产废水中的GaAs、Ga3+和Ge4+对活性污泥核酸和氨基酸的影响

研究了GaAs、Ga³⁺、Ge⁴⁺、Hg²⁺和Cr⁶⁺对活性污泥脱氧核糖核酸(DNA)和核糖核酸(RNA)的影响,以及GaAs对活性污泥氨基酸的影响。结果表明,Hg²⁺和Cr⁶⁺主要使活性污泥中核酸的DNA含量减少,GaAs则主要使RNA含量减少,Ge⁴⁺浓度达到300ppm/g MLSS对,无论对DNA还是RNA的合成都有较强的抑制影响。低浓度的GaAs对活性污泥氨基酸含量影响不大,而GaAs浓度达360ppm/g MLSS时则使活性污泥中氨基酸含量明显减少。     

电镀废水中铜锌铬镍对农业环境的影响

电镀废水排入河涌会污染农业环境。以广东省南 海市平洲地区为例,农田灌溉水中Ｃｕ、Ｚｎ、Ｎｉ的含量超过允许限值１ ～１４ 倍,河涌底泥Ｃｕ、Ｚｎ、Ｃｒ、Ｎｉ超标１２ ～３７倍,土壤超标０．５ ～２．９倍,作物超标０．３ ～８ 倍。进入河涌的Ｃｕ、Ｚｎ、Ｃｒ、Ｎｉ能较快沉积于底泥中。进入土壤的Ｃｕ、Ｚｎ、Ｃｒ、Ｎｉ主要累积在耕作层中。作物对Ｃｕ、Ｚｎ 的吸收能力远远高于对Ｃｒ、Ｎｉ的吸收能力,作物吸收系数是Ｚｎ ＞ Ｃｕ ＞ Ｎｉ＞ Ｃｒ     

土壤对酸沉降缓冲机制探讨

一、前言 土壤对酸沉降具有一定的缓冲作用,不同土壤的缓冲能力也各不相同。那么,土壤缓冲作用的本质是什么,不同土壤为什么具有不同的缓冲能力,要解决这些问题,就必须要了解土壤的缓冲机制,了解土壤内部的化学过程。     

灾害救助评估理论方法研究与展望

灾害救助评估是一种辅助决策工具,收集和分析灾害及灾害救助信息,为灾害救助活动的决策、规划和控制提供有效的信息支持,其内涵主要包括4个方面:①评估灾害对社会产生的影响;②灾害应急抢险需求与方案优化;③救助资源可获得性;④促进和加速灾后恢复与区域发展的可行性。灾害救助过程包括规划、数据收集与调查、分析与解读、趋势预测、辅助决策、灾害监测等6个环节。灾害救助评估内容按照灾害救助阶段总体分为应急快速评估和灾后详细评估两大类。其中,应急快速评估主要侧重于灾情和应急救助需求,是灾害救助评估的传统研究领域,为应急抢险和受灾人口基本生活保障提供信息支持;灾后详细评估则主要用于全面分析灾害对社会、经济、生态环境系统造成的损失和影响,为灾后恢复与重建提供辅助决策支持。     

电化学法用于微污染水脱氮处理实验

采用电化学方法,以轻度污染的温榆河河水为研究对象,考察了电化学方法对微污染地表水中氨氮的去除效果,探讨极板间距、反应时间以及板间电压对氨氮去除的影响。研究表明:反应时间为10min,板间距为1.0cm,板间电压为11V时,该方法对去除微污染水中氨氮有较好的处理效果,对氨氮的去除由原水的8～36mg/L降至2.4～11mg/L,去除率能达到70%以上,同时总氮的去除与氨氮去除呈现良好的相关性。     

湿地稻-鸭复合生态种养对甲烷菌种群数量影响的研究

采用厌氧培养箱技术．用最大或然数计数(MPN)法测定稻一鸭复合种养对水稻不同生育期土壤中的产甲烷菌种群数量的影响。结果表明,稻田土壤中产甲烷菌数量的变化规律与稻田甲烷排放的季节变化规律基本一致,早稻田土壤中菌数高峰期出现在孕穗期．晚稻田土壤中菌数高峰期出现在分蘖盛期。实行稻-鸭复合种养,显著降低了稻田土壤中甲烷细菌种群的数量。特别是减少了甲烷排放高峰期的甲烷细菌憨量。早稻田和晚稻田产甲烷菌种群数量分别比对照田降低20%-96．9％和94．3％～95．8％,且两系统土壤中甲烷细菌数量的差异达1％的显著水平。