Investigating activated sludge microbial population efficiency in heavy metals removal from compost leachate

Abstract

Solid waste production has increased in recent years. Many studies have shown that generated leachate from solid waste contains a high concentration of heavy metals. Their removal efficiency from leachate was investigated in aerobic suspended and attached growth systems in lab-scale within 72 hours of aeration. All of the materials used were analytical grade (Merck). Maximum efficiency of the attached growth system in removal of BOD5 and COD was, respectively, 80% and 78.28%. Maximum removal efficiency for both attached and suspended growth was related to lead, and minimum removal efficiency was related to vanadium for the attached growth, and cadmium for suspended growth. Heavy metals removal efficiencies in attached growth from max to min were lead, iron, manganese, cobalt, zinc, mercury, magnesium, copper, chromium, nickel, cadmium, and vanadium, respectively; and the removal efficiencies for suspended growth from max to min were lead, manganese, iron, zinc, copper, magnesium, cobalt, mercury, chromium, nickel, vanadium, and cadmium, respectively. Generally it can be concluded that both systems are suitable for young leachate treatment, but to satisfy environmental discharge standards post treatment will be necessary.