Abstract
Continuous biological treatment of paperboard mill wastewater under changes of organic loading rate (OLR) along with hydrogen production was investigated. The continuous experiments were conducted at different OLRs from 1.2 to 18.6 kg COD/L. d. The COD removal efficiency increased from 30.8 +/- 3.1 to 83.6 +/- 5.3% with decreasing OLR from 18.6 to 1.2 kg COD/L. d, respectively. TSS, VSS, and carbohydrates removal efficiencies were 86.5 +/- 5.11%, 81.6 +/- 1.7%, and 63.5 +/- 19%, respectively. Meanwhile, the hydrogen production rate was amounted the highest value of 4.74 +/- 0.9 L/d at OLR of 9.3 kg COD/L. d which coincided to the highest volatile fatty acids of 337 +/- 13.6 mg/l and HAc/HBu of 2.13 +/- 0.4. (C) 2015 The Authors. Published by Elsevier Ltd.