Anaerobic acidification of sugar-beet processing wastes: Effect of operational parameters

Alkaya E., Demirer G. N.

BIOMASS & BIOENERGY, vol.35, no.1, pp.32-39, 2011 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 35 Issue: 1
  • Publication Date: 2011
  • Doi Number: 10.1016/j.biombioe.2010.08.002
  • Journal Name: BIOMASS & BIOENERGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.32-39
  • Keywords: Anaerobic digestion, Sugar industry, Acidification, Volatile fatty acids, DAIRY MANURE, BIOGAS PRODUCTION, DIGESTION SYSTEM, RETENTION TIME, CO-DIGESTION, WATER, PULP, ACIDOGENESIS, WASTEWATERS, INDUSTRIAL
  • Middle East Technical University Affiliated: Yes

Abstract

The objective of this study was to maximize the hydrolysis and acidification of sugar-beet processing wastewater and beet pulp for volatile fatty acid (VFA) production through acidogenic anaerobic metabolism. Experiments were conducted to determine the optimum operational conditions (HRT, waste-mixing ratio and pH) for effective acidification in daily-fed, continuously mixed anaerobic reactors. For this purpose, reactors were operated at 35 +/- 1 degrees C with different combinations of HRT (2-4 days), wastewater-pulp mixing ratios (1:0-1:1, in terms of COD) and pH ranges (5.7-7.5). Increased OLRs, resulting from pulp addition, increased the amount of acidification products (VFAs) which led to relatively low operational pH values (5.7-6.8). In this pH range, methanogenic activity was successfully inhibited and the lowest methane percentages (5.6-16.3%) were observed in the produced biogas. The optimum operational conditions were determined to be 2-day HRT and 1:1 waste mixing ratio (in terms of COD) without external alkalinity addition. These operational conditions led to the highest tVFA concentration (3635 +/- 209 mg/L as H-Ac) with the acidification degree of 46.9 +/- 2.1%. (C) 2010 Elsevier Ltd. All rights reserved.