Christopher, L.Van Driessel, Brian2015-11-252015-11-252003-11http://hdl.handle.net/11660/1932English: Bleach plant effluent was characterised by physico-chemical methods. The chemistry of the bleach plant effluent was examined to devise effective treatment methods. Effluent contained trace amounts of nitrogen as well as carbohydrates and no ortho phosphate could be detected in the wastewater. The best decolourisation activities were obtained using adsorption as treatment method, with activated carbon removing > 99% colour from effluent. Chitosan (81%) and chitin (77%) could remove appreciable levels of colour from bleach plant effluent, followed by biomass from Rhizomucor pusillus, a mucoraelean fungus (71%). Chitosan and chitin from the cell wall of R. pusillus might be involved in the fungus decolourisation ability. Effluent pH was inversely related to effluent decolourisation when R. pusillus, chitosan or chitin was used as adsorbents. This might in part be due to acid catalysis during nucleophilic addition reactions, where amino groups of chitin/chitosan react with carbonyl groups in Eo-effluent. Also, chitin and chitosan amino groups can be protonated under acidic conditions and acquire positive charges that can interact with the chromophores found in Eo-effluent. However, pH exerted no significant effect on decolourisation when activated carbon was employed as adsorbent of effluent colour. Decolourisation employing commercial adsorbents seemed to be mainly due to chemisorption. Adsorption experiments conducted at various ionic strengths indicated that coulombic interactions are responsible for a fraction of the decolourisation activity of chitosan and chitin. Nevertheless, decolourisation obtained with RM7 and activated carbon was unaffected by the ionic strength. Flocculation of coloured compounds from Eo-effluent by chitosan containing solutions resulted in a maximum decolourisation of 75%. Anion-exchange treatment removed 96% colour from Eo-effluent. Ultraviolet irradiation could decolourise the Eo-effluent by about 42 to 43%. Decolourisation using organic solvent extraction proved ineffective with a highest colour removal efficiency of only 21% being achieved. Biological methods used for effluent remediation were: 1) Trickling filters, 2) Activated sludge reactors and 3) Rotating biological contactor reactors (RBC). Treatment using one biological system was followed by treatment in another system With trickling filters containing immobilised white-rot fungi, the highest decolourisation (61%) was obtained with Coriolus versicolor. This fungus required a co-substrate to efficiently decolourise the effluent. Effluent treatment in an activated sludge reactor reduced toxicity, COD and chlorophenol levels. However, colour and high molecular mass compounds were not affected significantly by this method of treatment. Decolourisation was studied in a RBC using immobilised C. versicolor and R. pusillus, respectively. The decolourisation rate by both fungi was proportional to initial colour intensities. Decolourisation was not adversely affected by colour intensity, except at the lowest level tested. Decolourisation of 53 to 74% could be attained using a hydraulic retention time of 23 h. Rhizomucor pusillus, removed 55% of AOX compared to a 40% AOX reduction by C. versicolor. Treatment employing R. pusillus and C. versicolor, respectively, rendered the effluent essentially non-toxic. Addition of nutrients to the decolourisation media stimulated colour removal by C. versicolor, but not significantly in the case of R. pusillus. Ligninolytic enzymes (manganese peroxidase and laccase) were only detected in effluent treated by C. versicolor. Decolourisation mechanisms were investigated using gel permeation chromatography. Rhizomucor pusillus decolourised the effluent by adsorption and C. versicolor removed effluent colour by adsorption as well as by biodegradation. Coriolus versicolor could decolourise the effluent for a period of 34 d whereas R. pusillus decolourised the effluent up to 54 d. Further improvements in effluent quality could be attained when treatment using one system was followed by treatment in another system, possibly because of toxicity reduction in the pre-treatment steps.Afrikaans: Fisiese en chemiese metodes was toegepas om bleik-effluent vanaf sulfiet pulp meul te karakteriseer. Die chemiese aard van die effluent moes bepaal word om effektiewe behandelings metodes te kon saamstel. Lae vlakke van stiksof en koolhidraat was aanwesig in die effluent. Orto-fosfaat was afwesig. Naastenby al die effluent kleur was verwyder gedurende adsorpsie eksperimente uitgevoer met geaktiveerde koolstof. Chitosan en chitin kon ook die effluent kleur tot ? beduidende mate verwyder. Rhizomucor pusillus biomassa was die volgende beste adsorbeermiddel van kleur na chitosan en chitin. Chitosan/chitin kan moontlik hoof komponent(e) wees van die selwand van R. pusillus en daarom belangrike bydrae lewer tot die kleur adsorpsie vermoë van die fungus. Ontkleuring deur chitosan, chitin en R. pusillus was omgekeerd eweredig aan die effluent pH. Dit kan gedeeltelik toegeskryf word aan suurkatalise gedurende nukleofiliese addisie reaksies waartydens aminogroepe van chitin en chitosan reageer met karbonielgroepe teenwoordig in die effluent. Verder, by lae pH vlakke kan die aminogroepe van chitosan en chitin positiewe ladings verkry en reageer met kleurgroepe in die effluent. Die pH het egter geen wesenlike effek getoon op die onkleuring veroorsaak deur geaktiveerde koolstof nie. Adsorpsie eksperimente uitgevoer in die teenwoordigheid van verskillende ioniese-sterktes het aangetoon dat gedeelte van die ontkleuring deur chitosan en chitin deur ioniese interaksies veroorsaak word. Hierteenoor, het die ioniese sterkte geen invloed getoon op die ontkleuring verkry met of geaktiveerde koolstof of R. pusillus nie. Flokkulasie van gekleurde verbindings in Eo-effluent het gelei tot maksimum ontkleuring van 75%. Anioon-uitruilings behandeling was effektief en 96% van die kleur kon daarmee verwyder word. Ultraviolet bestraling het 42 tot 43% ontkleuring veroorsaak. Ontkleuring deur ekstraksie van effluent met organiese oplosmiddels was oneffektief en die grootste ontkleuring verkry was slegs 21%. Biologiese behandelings is uitgevoer in: 1) biologiese filters (BF), 2) geaktiveerde slyk (AS) en 3) roterende biologiese kontaktor (RBK) reaktors. Behandeling in een reaktor is ook in sekere gevalle gevolg deur behandeling in ander reaktor. Behandeling in BF met Coriolus versicolor het maksimale ontkleuring (61%) veroorsaak. Die fungus het ko-substraat nodig gehad vir effektiewe ontkleuring . Behandeling in AS het tot verlaagde toksisiteits, COD en chlorofenool vlakke gelei. Tog kon die effluent kleur en die vlakke van hoë molekulêre massa verbindings nie noemenswaardig verlaag word nie. Ontkleuring was ondersoek in die RBK met geimmobiliseerde C. versicolor en Rhizomucor pusillus, onderskeidelik. Kleur verwyderings tempo’s met beide fungi was eweredig aan die inisiële kleur intensiteite gebruik. Vlakke van ontkleuring was laer wanneer effluent met kleur intensiteite < 2000 PCU behandel was. Ontkleurings van tussen 61 tot 74% was moontlik by hidroliese retensie tyd van 23 uur. Rhizomucor pusillus het 55% van die AOX verwyder in vergelyking met die 40% verwyder deur C. versicolor. Fungale behandeling met beide organismes, onderskeidelik het die effluent nie-toksies gelaat. Byvoeging van voedingstowwe tot die ontkleurings media van C. versicolor het ontkleuring gestimuleer, maar ontkleuring deur R. pusillus is nie daardeur beinvloed nie. Ligninolitiese ensiem aktiwiteite (mangaan peroksidase en lakasse) was slegs aanwesig in effluent behandel met C. versicolor. Ontkleuring meganismes is ondersoek deur gel permease chromatografie. Ontkleuring veroorsaak deur R. pusillus kon toegeskryf word aan adsorbsie, in teenstelling, C. versicolor het effluent kleur verwyder deur adsorpsie sowel as biodegradering. Coriolus versicolor kon die effluent ontkleur vir periode van 34 dae terwyl R. pusillus ontkleuring van die effluent vir 54 dae kon volhou. Verdere verbeterings in effluent kwaliteit kon verkry word indien een behandeling gevolg is deur ander biologies behandeling, moontlik as gevolg van toksisiteits verlaging teweeg gebring in die eerste behangdelings stap.enThesis (Ph.D. (Microbial, Biochemical and Food Biotechnology))--University of the Free State, 2003Bioremediation -- South AfricaWood-pulp industry -- Waste disposalWood-pulp -- Bleaching -- Environmental aspectsChloroorganicsBleach effluentBioremediationAdsorptionDecolourisationChitosanChitinWhite-rot fungiBiodegradation mechanismsThesisUniversity of the Free State