Pengolahan Limbah Cair Pabrik Penyamakan Kulit Secara Biol9ogi Dengan Aerasi

Yogyakarta has many leather industries. To process a hide, these industries use many chemicals such as natrium salt, dyes, and other organic materials. Some of these chemicals will be wasted and will become an environmental pollution-problem. The main objective of this study is to investigate the effect of time, air flow rate, the amount of nutrition and sludge to the effectiveness of leather wastewater treatment. Waste was added with an amount of NPK, TSP and sludge, and then bubbled with air continuously. Sample of waste was taken every 2 hour, then its pH, BOD and COD were analyzed. The result of the experiments showed that the decrease of BOD and COD were influenced by air flow rate, the amount of nutrition and sludge. For 1200 mL of wastewater with the BOD about 170 mg/L and COD 410 mg/L, the optimum condition of air flow rate, NPK, TSP, and sludge are 2776 mL/min, 2 g, 1 g, and 500 mL respectively. After the treatment has been operated during 8 hours, the BOD of product was about 45 mg/L and COD about 137 mg/L. The rate equation for this biological process was also obtained. Keywords: leather wastewater, effectiveness, BOD, COD, biological proces