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Modelling of a bioflocculant supported dissolved air flotation system for fats oil and grease laden wastewater pretreatment

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2017. / In the recent past, the poultry industry in South Africa has grown due to an increased demand of
poultry products as a result of population growth and improved living standards. Furthermore,
this has led to poultry slaughterhouses generating high strength wastewater which is laden with
a high concentration of organic and inorganic pollutants from the slaughtering process and
sanitation of equipment and facilities. As a result, South Africa has promulgated restrictions and
a set of quality standards for effluent discharged into the environment to minimize ecological
degradation and human health impact. Hence, there is a need for improved Poultry
Slaughterhouse Wastewater (PSW) pre-treatment prior to either discharge into municipal
wastewater treatment plants (WWTP) or on-site secondary treatment processes such as
anaerobic digesters. Additionally, amongst the pre-treatment methods for Fats, Oil and Grease
(FOG) laden wastewater, flotation remains the most popular with Dissolved Air Flotation (DAF)
system being the most applied. However, modelling and optimization of a biological DAF system
has never been attempted before in particular for a bioflocculant supported DAF (BioDAF) for
PSW pre-treatment. Process modelling and optimization involves process adjustment to
optimize influential parameters. In this study, Response Surface Methodology (RSM) was used
to develop an empirical model of a BioDAF for pre-treatment of PSW, for which a bioflocculant
producer including production conditions, flocculant type and its floc formation mechanism, were
identified.
Twenty-one (n = 21) microbial strains were isolated from the PSW and their flocculation activity
using kaolin clay suspension (4g/L) was quantified, with a mutated Escherichia coli (mE.coli)
[accession number LT906474.1], having the highest flocculation activity even in limited nutrient
conditions; hence, it was used for further analysis in other experiments. Furthermore, the
optimum conditions for bioflocculant production achieved using RSM were pH of 6.5 and 36°C
conditions which induced instantaneous bioflocculant production with the highest flocculation
activity. The bioflocculant produced by the mE.coli showed the presence of carboxyl/amine,
alkyne and hydroxyl functional groups, which was indicative that the bioflocculant contained
both polysaccharides and some amino acids.

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:cput/oai:localhost:20.500.11838/2637
Date January 2017
CreatorsMukandi, Melody
ContributorsNtwampe, SKO, Basitere, M
PublisherCape Peninsula University of Technology
Source SetsSouth African National ETD Portal
LanguageEnglish
Detected LanguageEnglish
TypeThesis
Rightshttp://creativecommons.org/licenses/by-nc-sa/3.0/za/

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