Enhancing Phosphorus Recovery from Septic Tank Sludge Through Anaerobic Digestion as Biofertilizer- Effect of pH and Temperature

Phosphorus (P) is considered a limited and non-renewable mineral source that is essential in our daily lives. It is essential nutrient required for plant growth and development. Septic tank sludge (STS) is a residual waste generated from wastewater treatment which rich in organic matter and essential nutrient such as P. Instead of being disposed of as waste, it can serve as a resource for nutrient recovery. One effective method for this is anaerobic digestion (AD). Therefore, this study carried out to investigate the highest of reactive P recovery and time digestion, with a focus on optimizing pH and temperature conditions. The physicochemical and biological of raw STS was determined, and it was reported that waste was suitable to undergo the AD process. Optimization of pH 4.0 show the highest of reactive P recovery with value 22.99 mg/L ± (0.21), followed by pH 5.0 with 20.58 mg/L ± (0.15) and the lowest recovery was pH 6.0 with 19.65 mg/L ± (0.12). All digestion day was at day 9. While in temperature optimization, resulted 55.0 ℃ ± (1.0) recovered the highest of reactive P with 69.95 mg/L ± (0.12). Followed by 35.0 ℃ ± 1.0 (25.78 mg/L ± 0.05), and 45.0 ℃ ± 1.0 (17.56 mg/L ± 0.13), respectively. These findings indicate optimizing of pH and temperature significantly can enhance the P recovery efficiently. Moreover, this study also provides information on new strategies used in recovering P.