The effect of pH on anaerobic fermentation of primary sludge at room temperature

• Published in: Journal of hazardous materials Vol. 172; no. 1; pp. 196 - 201
• Main Authors: Wu, Haiyan, Yang, Dianhai, Zhou, Qi, Song, Zhoubing
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.12.2009; Elsevier
• Subjects: Acetic Acid - isolation & purification; Ammonia - chemistry; Anaerobiosis; Applied sciences; Biological and medical sciences; Bioreactors; Biotechnology; Carbohydrates; Carbon; Carbon - chemistry; Exact sciences and technology; Fatty acids; Fatty Acids, Volatile - chemistry; Fermentation; Fundamental and applied biological sciences. Psychology; General treatment and storage processes; Hydrogen-Ion Concentration; Hydrolysis; Methods. Procedures. Technologies; Nutrient removal; Others; Oxygen demand; Pentanoic Acids - isolation & purification; Phosphorus - chemistry; Pollution; Polystyrene resins; Primary sludge (PS); Propionates - isolation & purification; Sewage; Short-chain fatty acids (SCFAs); Sludge; Temperature; Various methods and equipments; Waste Disposal, Fluid - methods; Wastes; Water Pollutants, Chemical - isolation & purification; Water Purification - methods; Hydrolysis; Nutrient removal; pH; Short-chain fatty acids (SCFAs); Primary sludge (PS); Waste treatment; Phosphorus; Fermentation; Fatty acids; Anaerobic digestion; Ammonia; Short-chain fatty acids (SCFAS); Chemical oxygen demand; Production; Water quality; Biological treatment
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2009.06.146

The effect of pH in the range of 3.0–11.0 on anaerobic fermentation of primary sludge (PS) was investigated at room temperature. The experimental results showed that the concentrations of soluble chemical oxygen demands (SCOD), soluble protein and carbohydrate and short-chain fatty acids (SCFAs) under alkaline conditions were significantly higher than those under other pHs. At fermentation time of 5 days, the average SCFAs concentration increased from 968 to 3511 mg COD/L with the increase of pH from 3.0 to 10.0. However, further increasing pH to 11.0 resulted in the decrease of SCFAs. At pH 10.0, acetic, propionic and iso-valeric acids were the three main products, and the volatile suspended solids (VSS) reduction reached 38%. It was also observed that at any pH value investigated, there were obvious ammonia and phosphorus releases during fermentation. According to this study it is obvious that alkaline pH benefited the soluble organic carbon production from PS.