Efficiency of operating of Kaunas WWTP digester

Abstract

Management of waste water sludge is one of the most topical environmental problems that is being gradually solved in Lithuanian waste water treatment plants. Anaerobic sludge digestion is an essential part of sludge treatment. Digestion process not only mineralizes organic pollutants and reduces amount of sludge, but also produces biogas which can be used for energy needs. Different technological and hydraulic factors affect work efficiency of digester. This article analyses the effect of temperature, amount and composition of sludge as well as the process of stirring sludge on gas discharge in Kaunas WWTP digester. It has been determined that degradation degree of organic material affects production of biogas. Sludge digestion process is performed in a narrow temperature interval and for this reason no temperature effect has been observed on the machinery. By stirring sludge effectively a better biogas output can be obtained.