Treatment of Dairy Industry Wastewater by Anaerobic Processes

Abstract

Recently, with the development of industrialization and rapid population growth, natural resources are rapidly depleting and the negative effects of the wastes produced on the environment and human health are in sight. The dairy industry in the constantly growing food sector is also one of the sectors with the highest amount of wastewater per unit production. It originates from other by-products such as cheese, butter, ice cream, yoghurt and dry milk powder, as well as clean water from heating and cooling systems, and wastewater from washing plants and machinery. Wastewater is not reused due to the amount of pollution in the high concentrate it contains, and it poses a threat to the environment if not treated properly. Poses a threat to due to the worldwide distribution of the dairy industry and the characterization of the wastewater generated, many studies have been carried out in this area and different technologies are applied. Many different treatment technologies are applied in the wastewater treatment, generally physicochemical and biological processes. Anaerobic treatment provides energy recovery with methane gas production, besides its advantages such as less energy and cost requirement and low amount of sludge formation compared to the aerobic treatment. Anaerobic treatment technologies with high organ- ic matter and other pollutants are successfully applied in dairy industry wastewater treatment. Long chain fatty acids, which are limiting factors encountered in the treatment of dairy industry wastewater, prevent methanogenic activity. Optimum operating parameters must be provided for the successful operation of anaerobic processes. In the dairy industry wastewater, many anaerobic bioreactors are applied in different operating conditions. In the studies, the reactors that were put into operation under different conditions (reactor type, temperature, pH, hydraulic retention time, organic loading rate) were examined and the efficiency on the dairy industry wastewater was revealed. In this evaluation article, anaerobic processes applied in dairy industry wastewaters with high pollution levels are examined and information about issues such as treatment performance, operational approaches, organic matter removal and methane production efficiency are given.