pH-adjustment strategy for volatile fatty acid production from high-strength wastewater for biological nutrient removal.
Volatile fatty acid (VFA) production from three types of high-strength organic wastewater (cassava thin stillage, starch wastewater and yellow-wine processing wastewater) were compared. The results showed that cassava thin stillage was the most suitable substrate, based on its high specific VFA production (0.68 g chemical oxygen demand (COD)/g initial soluble chemical oxygen demand (SCOD)) and yield (0.72 g COD/g SCOD) as well as low nutrient content in the substrate and fermented liquid. The acid fermented cassava thin stillage was evaluated and compared with sodium acetate in a sequencing batch reactor system. Total nitrogen removal efficiency was higher with fermented cassava thin stillage than with the sodium acetate. The effects of pH and a pH-adjustment strategy on VFA production and composition were determined using cassava thin stillage. At an initial pH range of 7-11, a relatively high VFA concentration of about 9 g COD/L was obtained. The specific VFA production (g COD/g initial SCOD) increased from 0.27 to 0.47 to 0.67 at pH 8 and from 0.26 to 0.68 to 0.81 at pH 9 (initial pH, interval pH, and constant pH adjustment, respectively). The dominant VFA species changed significantly with the increasing frequency of the pH adjustment. Further studies will examine the metabolic pathways responsible for VFA composition.
Key Laboratory of the Yangtze River Water Environment, Ministry of Education, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail: sally.xieli@tongji.edu.cn.
Li
L
Xie
Key Laboratory of the Yangtze River Water Environment, Ministry of Education, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail: sally.xieli@tongji.edu.cn.
Hui
H
Liu
Key Laboratory of the Yangtze River Water Environment, Ministry of Education, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail: sally.xieli@tongji.edu.cn.
Yin-Guang
YG
Chen
Key Laboratory of the Yangtze River Water Environment, Ministry of Education, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail: sally.xieli@tongji.edu.cn.
Qi
Q
Zhou
D019149:Bioreactors; D005232:Fatty Acids, Volatile / Q000737:chemistry*; D005285:Fermentation; D019649:Food Industry; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D002365:Manihot / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*
D005232:Fatty Acids, Volatile; D007220:Industrial Waste; D009584:Nitrogen