The use of exogenous microbial species to enhance the performance of a hybrid fixed-film bioreactor treating coal gasification wastewater to meet discharge requirements

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dc.contributor.author Rava, Eleonora Maria Elizabeth
dc.contributor.author Chirwa, Evans M.N.
dc.contributor.author Allison, P.
dc.contributor.author Van Niekerk, M.
dc.contributor.author Augustyn, M.P.
dc.date.accessioned 2016-08-31T07:02:44Z
dc.date.available 2016-08-31T07:02:44Z
dc.date.issued 2016-07
dc.description.abstract The objective of this study was to determine whether inoculating a hybrid fixed-film bioreactor with exogenous bacterial and diatoma species would increase the removal of chemical oxygen demand, nitrogenous compounds and suspended solids from a real-time coal gasification wastewater to meet environmental discharge requirements specified for petrochemical refineries. The COD removal increased by 25% (45% to 70%) at a relatively high inoculum dosage (370 g∙m−3) and unit treatment cost (12.21 €∙m−3). The molar ratio of monovalent cations to divalent cations (M/D >2) affected nitrification, settling of solids and dewatering of the sludge. The use of a low-charge cationic flocculant decreased the suspended solids in the effluent by 70% (180 mg∙L−1 to 54 mg∙L−1) and increased the sludge dewatering rate by 88% (61 s∙L∙g−1 to 154 s∙L∙g−1) at a unit treatment cost of 2.5 €∙t−1 dry solids. Organic compounds not removed by the indigenous and exogenous microbial species included benzoic acids (aromatic carboxylic acids), 2-butenoic acid (short-chain unsaturated carboxylic acid), I(2H)-isoquinolinone (heterocyclic amine), hydantoins (highly polar heterocyclic compounds), long-chain hydrocarbon length (carbon length > C15) and squalene. These organic compounds can thus be classified as poorly degradable or nonbiodegradable which contributed to the 30% COD not removed by the H-FFBR. The use of exogenous microbial species improved the quality of CGWW; however, not sufficiently to meet discharge requirements. The cost of such treatment to meet discharge requirements would be unsustainable. Alternative technologies need to be investigated for reusing or recycling the CGWW rather than discharging. en_ZA
dc.description.department Chemical Engineering en_ZA
dc.description.librarian am2016 en_ZA
dc.description.sponsorship The authors would like to thank Buckman Africa for financing the chemical and microbiological analyses and Sasol Group Technology (Pty) Ltd for the use and operation of the pilot plant. en_ZA
dc.description.uri http://www.wrc.org.za en_ZA
dc.identifier.citation Rava, E, Chirwa, E, Allison, P, Van Niekerk, M & Augustyn, MP 2016, 'The use of exogenous microbial species to enhance the performance of a hybrid fixed-film bioreactor treating coal gasification wastewater to meet discharge requirements', Water SA, vol. 42, no. 3, pp. 483-489. en_ZA
dc.identifier.issn 0378-4738 (print)
dc.identifier.issn 1816-7950 (online)
dc.identifier.other 10.4314/wsa.v42i3.14
dc.identifier.uri http://hdl.handle.net/2263/56520
dc.language.iso en en_ZA
dc.publisher Water Research Commission en_ZA
dc.rights Published under a Creative Commons Attribution Licence. en_ZA
dc.subject Ammonia en_ZA
dc.subject Catalytic reactor technology en_ZA
dc.subject Fixed-film bioreactor en_ZA
dc.subject Hydantoins en_ZA
dc.subject Thiocyanates en_ZA
dc.subject Chemical oxygen demand (COD) en_ZA
dc.title The use of exogenous microbial species to enhance the performance of a hybrid fixed-film bioreactor treating coal gasification wastewater to meet discharge requirements en_ZA
dc.type Article en_ZA


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