Waste Sludge Characteristics of a Wastewater Treatment Plant Compared with Environmental Standards

Abstract

Sludge production is an avoidable problem arising from the treatment of wastewater. The sludge remained after municipal wastewater treatment contains considerable amounts of various contaminants and if is not properly handled and disposed, it may produce extensive health hazards. On the other hand, this sludge has benefits for plants and soils. Thereupon, land application of sludge has received much attention over the traditional incineration and dump in sea. The comprehensive regulations of U.S.EPA title 40 CFR parts 503 include criteria and standards for land application of sludge. One of the most important wastewater treatment plants in Tehran, Iran is Shoosh Plant, which applies its waste sludge in agricultural lands after dewatering in drying beds. In this research, waste sludge from drying beds was examined according to 40 CFR parts 503. Results indicate that the dehydrated sludge has not the characteristics required for final discharge. If the dewatering process in the existing beds of the plant would be modified according to title 40 CFR part 503, the standard of Pathogen Reduction class B would be achieved. Waste sludge of drying bed must be applied in agricultural land with respect to the conditions of application method that is presented in vector attraction reduction. Concentration of this waste sludge is less than ceiling concentration limits identified by title 40 CFR parts 503.