PRELIMINARY INVESTIGATION OF ANAEROBIC CO-DIGESTION POTENTIAL OF PRIMARY AND SECONDARY SEWAGE SLUDGE FRACTIONS WITH FRUIT WASTE

• Published in: Konya Journal of Engineering Sciences
• Main Author: Erdirençelebi, Dilek
• Format: Article in Journal/Newspaper
• Language: English
• Published: Konya Technical University 2021
• Subjects: Sewage sludge; co-digestion; organic waste; biogas; energy; Arıtma çamuru; anaerobik; çürütme; organik atık; biyogaz; enerji; Ön; Carbonic acid
• Online Access: https://hdl.handle.net/20.500.13091/1978; https://doi.org/10.36306/konjes.887973; https://dergipark.org.tr/tr/pub/konjes/issue/60526/887973; https://dergipark.org.tr/tr/download/article-file/1606445

DergiPark: 887973 konjes Co-digestion feasibility of primary (PS) and secondary (SS) sewage sludge fractions produced in a municipal wastewater treatment plant (WWTP) was investigated by the mixing of fruit waste in sequential batch reactors. Toxic threshold level for pH was exceeded as fruit waste digestion produced a high level of volatile fatty acid (VFA) concentration. Alkali (NaOH) addition provided an optimum level of pH at 7.95-8.05 and 8.16-8.25 in the co-digestion of PS and SS, respectively, and efficient conversion of VFA to methane gas eliminating VFA accumulation. Buffered co-digestion resulted in 55% (+227-271 mL) and 400% (+501-546 mL) increase in biogas production compared to solely PS and SS stabilization. Fruit waste digestion’s positive effect was obtained at a higher level in SS digestion. pH rather than VFA proved to be the key parameter and NaOH highly effective as an alkali source producing double buffering effect by converting carbonic acid produced to bicarbonate alkalinity. High carbohydrate content of fruit waste exhibited a beneficial potential to neutralize high pH occurring in PS and SS digestion, thus, minimize free ammonia toxicity balancing hydroxide alkalinity formed from protein hydrolysis. Optimization of fruit waste loading rate based on pH will enable surplus energy gain and stable operation in sewage sludge and protein-rich wastewater digestion. Kentsel atıksu arıtma tesislerinde (AAT) oluşan primer (PÇ) ve sekonder (SÇ) arıtma çamurlarının meyve atığı ile birlikte anaerobik çürütme çalışması ardışık kesikli reaktörlerde yürütülmüştür. Proseste meyve atığının parçalanması ile yüksek seviyede uçucu yağ asitleri (UYA) oluşarak toksik pH eşiği geçilmiştir. Alkali kaynağı olarak NaOH ilavesi sonrasında pH PÇ ve SÇ için sırasıyla 7.95-8.05 ve 8.16- 8.25 olarak alkali seviyelerde gerçekleşmiş ve UYA’nın etkin metana dönüşümü ile biyogazda sırasıyla (+227-271 mL) ve 0 (+501-546 mL) artış elde edilmiştir. Meyve atığının aynı alkali şartta SÇ için daha yüksek verim ve proses ...