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SOLIDIFICATION AND NATURAL TREATMENT OF ARSENIC SLUDGE PRODUCED FROM

含砷污泥的固化与自然处理

基本信息

批准号：
16254003
负责人：
YOKOTA Hiroshi
金额：
$ 17.22万
依托单位：
UNIVERSITY OF MIYAZAKI
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16254003/
关键词：
Arsenic Groundwater Arsenic removal Treatment of sludge Natural treatment Cement solidification Micro-organism

项目摘要

We have established the design chart of the arsenic removal unit, Gravel Sand Filter (GSF), by examining the arsenic removal performance of 4 GSFs installed in Bangladesh these 4 years. These GSFs are community-based units and have supplied arsenic-safe water to villagers in these years. GSF is composed of gravel tanks and sand tank. The arsenic in groundwater is to be settled in the gravel voids of gravel tanks by co-precipitation with iron, which exits naturally in groundwater with higher concentration.The iron and arsenic in groundwater are first to be oxidized at the inlet tank of GSF. The aeration, contact between iron and arsenic, and the concentration of competition ions as phosphate are key points for the performance of GSF. The design methods for these poi its are proposed in this research. The performance of GSF is usually O.K with 10 value of ratio, Fe/As, in groundwater. The ratio of Fe/As should be, however, bigger 30 for the groundwater with high concentration of phosphat … More e. The box filled with large amount of used iron nails is to be set in the inlet tank in the design chart of GSF, when GSF has to be installed at the cite where the groundwater has less ratio of 30 under the higher concentration of phosphate.Arsenic sludge from GSF is to be settled in the sludge tank installed in the GSF cite through draining. The supernatant of the sludge tank is flowed to the artificial pond where the natural treatment of arsenic is examined. The settlement of the sludge tank is solidified by cement. The 90% of arsenic in the settlement is shut out without cement but the arsenic concentration of the leaching test was 0.05〜0.65mg/L, showing beyond values of standards 0.05mg/L in Bangladesh. The leaching tests for the 2% mixing of cement show 0.05〜0.11mg/L, which is less than the second standard for land contamination in Japan, 0.30mg/L..The pH of the tests shows 10.5-10.9.The treatment method, here, is to mix the sludge settlement with 2% cement and deposit without contact to water until the establishment of waste treatment management in Bangladesh.We have estimated the accumulation of arsenic at the bottom of the artificial pond and looked for the micro-organism in the bottom soil which can change the inorganic arsenic to organic one. We can detect some of Monomethylarsine(MMA) andDimethylarsine(DMA) in both of sludge tank and artificial pond. And, the micro-organism strong to arsenic was confirmed, which can live under the condition of arsenic concentration of 1000mg/L. Less

通过对4年来安装在孟加拉国的4个砂滤装置的除砷性能的考察，我们建立了除砷装置-砂滤装置的设计图。这些GSF是以社区为基础的单位，这些年来一直向村民提供砷安全的水。GSF由砾石罐和砂罐组成。地下水中的砷与地下水中天然存在的较高浓度的铁共沉淀，沉淀在砾石池的砾石空隙中，地下水中的铁和砷首先在GSF入口池处被氧化。曝气、铁砷接触、磷酸盐等竞争离子浓度是影响GSF性能的关键。本研究提出了这些点的设计方法。地下水中Fe/As比值为10时，GSF的性能一般较好。但对于高磷地下水，Fe/As值应大于30 ...更多信息 e.当GSF必须安装在地下水比小于30且磷酸盐浓度较高的地点时，GSF设计图中的进水池中设置了装有大量废旧铁钉的箱子，GSF产生的砷泥通过排水进入GSF地点的泥池中沉淀。污泥池的上清液流入人工池塘，在那里对砷的自然处理进行检查。污泥池的沉降采用水泥固化。沉降物中90%的砷在没有水泥的情况下被阻隔，但浸出试验的砷浓度为0.05 ~ 0.65mg/L，显示出超过孟加拉国标准0.05mg/L的值。水泥掺入量为2%时的浸出试验结果为0.05 ~ 0.11mg/L，低于日本土地污染第二标准0.30mg/L。试验的pH值为10.5- 10.9。处理方法是将沉淀的污泥与2%的水泥和存款混合，不与水接触，直到孟加拉国建立废物处理管理。我们估算了人工池塘底部的砷积累量，并寻找了底部土壤中能将无机砷转化为有机砷的微生物。在污泥池和人工池塘中均能检测到一定量的甲基胂（MMA）和二甲基胂（DMA）。同时，确定了一株对砷有较强耐受性的微生物，该微生物能在砷浓度为1000 mg/L的条件下存活。少