Abstract

All wastewater treatment processes produce a large amount of semisolid pollutants, especially wastewater sludge. Discharge of sludge without environmental considerations will have many serious effects on public health and environment. The main objective of this study is the selection of optimum option for sludge disposal in the Guilan province of Iran using rapid impact assessment matrix (RIAM) which is a tool to organise, analyse and present the results of a holistic environmental impact analysis (EIA). The effects of five options of sludge disposal (sludge composting, co-composting, grass land application, sanitary landfill and incineration) on four environmental components (physical-chemical, biological-ecological, social and economical) are evaluated via questionnaires which were was addressed to all environmental experts in water and wastewater companies in Guilan province. It was found that there are different optimum options for each environmental component. Based on overall comparison of the options' effects on all the components, the analysis of matrices has shown that co-composting is the best recommended option for sludge disposal in the existing conditions.

Key words: Sludge disposal, environmental impact assessment (EIA), rapid impact assessment matrix (RAIM), Guilan province, environmental components.