城市污泥植物处理系统与污泥中转处理场建设

Phyto-treatment system of municipal sewage sludge and transitional disposal site

目前城市污水处理厂污泥处理利用的主要障碍是污泥中过多的水分和重金属,增加运输、处理成本,造成二次污染问题。文章首先回顾了城市污泥的主要处理处置方法及其特点;接着介绍了污泥农用的作用和限制;主要阐述了用污泥干化床同时种植重金属超富集植物、低累积作物或钾高累积植物,通过植物提取降低城市污泥重金属含量,同时生产植物产品,并使污泥干化和稳定化的城市污泥特种植物处理系统;最后,针对一种处理方法难以消化一个大城市全部污泥的现状,提出城市污泥中转处理场的设想,把植物处理系统、堆肥、太阳能干燥、有机肥和复合肥生产、建材制造等多项技术集成,建立城市污泥专用处理和集散基地,解决日益增多的城市污泥的处置问题。其成本应低于目前采用的填埋、焚烧、制砖等处理方法,具有显著的社会、经济和环境效益。

The excess of water and heavy metals in sewage sludge is the main obstacle fol the treatment and reuse oflnunicipal sewage sludge in China. It can increase the cost of transport and treatment of sewage sludge and cause the secondary pollution. This paper reviews firstly the main treatment technologies of sewage sludge, then introduces the role of land application, inainly discuss a plant-treatment system with sludge drying bed on which a inetal-hyperacculnulating plant and a low-accumulating crop or a K-high accumulating plant are co-cropped, This system can reduce the metal contents in the treated sludge by phytoextraction of heavy metals, simultaneously produce crop, stabilize and dry the sludge at low cost. Finally, as a single method is difficult to treat and dispose the huge amount of sewage sludge for a big city, this paper proposes a transitional disposal site for treating municipal sewage sludge. This transitional disposal site is similar to normal landfill sites, but it combines sludge treatment with green plants, sludge composting, sludge drying with sunlight, organic fertilizer and compound fertilizer making and also construction materials fabrications, and the sludge is rotated to final end-uses and never totally-fulfill the site. This treatment option could be more economic and environinent-friendly than normal landfilling, incineration and brick fabrication of sewage sludge.