Remediation Technology and Typical Case Analysis of Informal Landfills in Rainy Areas of Southern China

A typical informal landfill in a rainy area of southern China was taken as an example in this study. The comprehensive control ideas and processes of the informal landfill site were systematically reviewed. The basic situation for the early stage of the government survey and investigation was provided, including a waste stock survey, water volume measurement, and a waste source survey. The main contents and key factors of a comprehensive investigation of the environmental quality status were briefly summarized. The water quality in the landfill, groundwater quality inside and outside of the site, and heavy metals in the bottom sediment were all determined. A low-cost practical landfill technology was explored to reduce the Chemical Oxygen Demand CODCr concentration of polyaluminum ferric chloride (PAFC), and NH4+-N was removed by calcium hypochlorite. Soil backfill was replaced, such that the informal landfill site was immobilized, which was perfectly suitable for this southern rainy area. This study proposes rules for a comprehensive improvement scheme for a landfill, and provides a reliable theoretical basis and practical experience for the treatment of similar informal landfills.