Development of a novel sewage treatment system for developing countries.

为发展中国家开发新型污水处理系统。

基本信息

批准号：
13355022
负责人：
OHASHI Akiyoshi
金额：
$ 25.21万
依托单位：
Nagaoka University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13355022/
关键词：
Developing countries Sewage treatment Low cost Methane Molecular biology UASB DHS Nitrification and Denitrification

项目摘要

Current sewage treatment system such as activated sludge is not suitable in developing counties due to high costs and high energy requirement. An "appropriate technology" of sewage treatment must be developed for developing countries. Recently UASB is attractive technology for sewage treatment in developing countries since it guarantees low construction and operational cost, produce energy as methane and less amount of sludge. However UASB alone can not meet discharge criteria, so that further option is needed to polish up UASB effluent without losing UASB strong point. As a proper system, we have proposed DHS (Down-flow Hanging Sponge) reactor. The principle of DHS is the use of a polyurethane sponge as a medium to retain biomass. The concept is similar to that of tricking filter, except that the packing material is sponge, which has a void space of more than 90%, resulting in a significant increase in entrapped biomass and thus longer solid retention time (SRT). As the sponge in a DHS is not submerged and freely hung in the air, oxygen is dissolved into the wastewater when it flows down the reactor. Therefore there is no need for external aeration or any other energy inputs. Moreover, production of excess sludge from DHS is negligible as longer SRT provides considerable time for autolysis of sludge in the system itself.Demonstration-scale DHS reactor with a treatment capacity of 1,000m^3・d^<-1> has been installed since 2002 by Indian government in India. We monitored this system as well as last year. DHS reactor has been operated at HRT of 1.49hr. As a long-term experimental period, we can see the excellent performance of DHS in terms of BOD, COD and fecal coliform removal which were 93%, 88% and 2 order, respectively without any problem. As a these result, a real scale DHS is planned on constructing in Agra city, India by Indian government.

由于高成本和高能源需求，现有的污水处理系统（例如活性污泥）不适合发展中国家，因此必须开发适合发展中国家的污水处理“合适的技术”。它保证了较低的建设和运营成本，产生甲烷能源和较少量的污泥，但单独使用UASB无法满足排放标准，因此需要进一步选择对UASB废水进行净化。作为一种合适的系统，我们提出了DHS（下流式悬挂海绵）反应器。DHS的原理是使用聚氨酯海绵作为介质来保留生物质，其概念与滴流类似。过滤器的不同之处在于填料是海绵，其空隙率超过 90%，导致截留的生物量显着增加，从而延长了 DHS 中的海绵的固体保留时间 (SRT)。没有浸没并自由悬浮在空气中，当废水流下反应器时，氧气会溶解到废水中，因此不需要外部曝气或任何其他能量输入，而且，由于 SRT 提供的时间较长，DHS 产生的剩余污泥可以忽略不计。系统本身的污泥自溶需要相当长的时间。处理能力为1,000m^3・d^<-1>的示范规模DHS反应器已安装2002年，我们在印度对DHS反应器进行了监测，在HRT为1.49小时的情况下进行了长期的实验，我们可以看到DHS在BOD、COD方面的优异表现。和粪便大肠菌群去除率分别为 93%、88% 和 2 个数量级，没有任何问题。因此，印度政府计划在印度阿格拉市建设真正规模的 DHS。