혐기소화액 탈수 효율 최적화를 위한 응집약품 대체 가능성 평가 연구

초록

This study aims to improve the dewatering efficiency of anaerobic digestate generated during the treatment of organic waste by addressing the drawbacks of the conventional coagulant ferric chloride (FeCl3) and evaluating the potential of alternative agents. Ferric chloride is known to cause severe corrosion, shortening equipment lifespan, and to lower the pH of filtrate, thereby imposing additional loads on subsequent treatment processes. Solving these issues is essential to ensure the stability and economic feasibility of the anaerobic digestion process. Laboratory- and pilot-scale tests were conducted to evaluate the performance of polyferric sulfate (PFS) and polymer, both individually and in combination. The results showed that a combined dosage of 20.6% PFS and 300 ppm polymer achieved the best performance, reducing the moisture content of the dewatered cake to 70%. This combination is expected to lower chemical costs by approximately 48% compared to the use of ferric chloride alone. In continuous operation tests, the modified coagulant maintained a stable moisture content below 70%; however, adhesion of the dewatered cake to the filter plates was observed, indicating the need for periodic cleaning. Additionally, aeration of the anaerobic digestate to reduce electrical conductivity was found to shorten the filtration time by 40–50% and reduce coagulant consumption by 20–30%, demonstrating potential for further process optimization.

키워드