Removal of hard COD, nitrogenous compounds and phenols from a high-strength coal gasification wastewater stream

Authors

  • E Rava University of Pretoria, Water Utilisation Division, 0002, South Africa
  • E Chirwa University of Pretoria, Water Utilisation Division, 0002, South Africa
  • P Allison Scientific and Technical Consulting Services, P.O. Box 699, Port Alfred 6170, South Africa
  • M van Niekerk Sasol Technology (Pty) Ltd, Private Bag X1034, B4901, Secunda 2302, South Africa
  • MP Augustyn Sasol Technology (Pty) Ltd, Private Bag X1034, B4901, Secunda 2302, South Africa

DOI:

https://doi.org/10.4314/wsa.v41i4.02

Keywords:

ammonia stripping, AnoxKaldness, coal gasification, fixed-biofilm reactor, hydantoins, phenosolvan, Pseudomonas, refinery effluent, thiocyanate

Abstract

The objective of this study was to identify the factors affecting the suspended and fixed biomass in the removal of hard COD, nitrogenous compounds and phenols from a coal gasification wastewater (CGWW) stream using a hybrid fixed-film bioreactor (H-FFBR) process under real-time plant operational conditions and actual wastewater composition. The composition of the influent and effluent was studied to determine which compounds were not removed by hydrolysis (bacterial activity) and how this correlated to the suspended and fixed biomass activity, COD and phenol removal. A H-FFBR with 12 g∙m−3 attached biomass and 440 mg∙ℓ−1 suspended biomass achieved 78% phenol removal and 49% COD removal but insignificant removal of nitrogenous compounds. During the operation period, fixed biomass concentration was higher than the suspended biomass. Parameters such as pH, phenols, alkalinity, metal ions, conductivity, total dissolved solids and aeration rate affected the fixed biofilm properties such as adhesion, thickness and structure. It can be concluded that the composition of the effluent had a direct effect on the fixed biomass properties and thus a direct effect on the removal of phenols, COD and nitrogenous compounds in the wastewater.

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Published

2015-07-24

Issue

Vol. 41 No. 4 July (2015): Water SA

Section

Research paper

License

Copyright (c) 2022 E Rava, E Chirwa, P Allison, M van Niekerk, MP Augustyn

Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

Creative Commons License

The content of this journal is licensed under a Creative Commons Attribution Licence.  Users are permitted to read, download, copy, distribute, print, search or link to the full texts of the articles in this journal under the terms of this Licence, without asking prior permission from the publisher or the author, provided the source is attributed. Copyright is retained by the authors.

How to Cite

E Rava (2015) “Removal of hard COD, nitrogenous compounds and phenols from a high-strength coal gasification wastewater stream”, Water SA, 41(4 July). doi:10.4314/wsa.v41i4.02.