International Journal of
Water Resources and Environmental Engineering

  • Abbreviation: Int. J. Water Res. Environ. Eng.
  • Language: English
  • ISSN: 2141-6613
  • DOI: 10.5897/IJWREE
  • Start Year: 2009
  • Published Articles: 315

Full Length Research Paper

Aerobic mesophilic treatment of potato industry wastewater

Manhokwe S.
  • Manhokwe S.
  • Midlands State University, Department of Food Science and Nutrition, P. Bag 9055, Gweru, Zimbabwe.
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Parawira W.
  • Parawira W.
  • Bindura University of Science Education, P. Bag 1020, Bindura, Zimbabwe
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Zvidzai C.
  • Zvidzai C.
  • Chinhoyi University of Technology, Department of Biotechnology, P. Bag 7724, Chinhoyi, Zimbabwe
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  •  Received: 23 February 2015
  •  Accepted: 25 June 2015
  •  Published: 24 July 2015

Abstract

An evaluation of a laboratory-scale aerobic method for the treatment of potato-processing wastewater at 37°C was investigated. Composite samples were collected to establish batch variations. The wastewater was characterized for Chemical Oxygen Demand (COD), Permanganate Value (PV), Total Solids (TS), phosphates and pH over a period of 6 months. Wastewater with an average of 6.8 g COD/l, high concentration of total solids (up to 6725 mg/l), and low pH was subjected to active sludge treatment in a Continuously Stirred Tank Reactor (CSTR) with Organic Loading Rates (OLRs) gradually increased from 3.4 to 12.1 g COD/litre/day. Stepwise increase in OLR reduced average COD reduction from 86% at 3.4 g COD/litre/day to 76% at 12.1 g COD/litre/day.  High rates of treatment efficiency (TE) were recorded at low OLRs (<6.8 g COD/litre day) with a notable pH of the effluent increasing from 4 to neutral values. TS reduction was achieved at 57% at HRT of 2 d. This study indicated that biological methods can be used for treatment of potato-processing wastewater in order to reduce the organic load and other pollutants acceptable levels for municipal discharge.

 

Key words: Potato wastewater, biotreatment, mesophilic, continuous stirred tank reactor (CSTR), activated sludge.