The development of an audit procedure and treatment technologies for Rupert and Rothschild vignerons' winery wastewater
Marais, Dulcie (2001-03)
Thesis (MScEng (Chemical Engineering))--University of Stellenbosch, 2001.
304 leaves single sided printed,preliminary pages i-xxii and numberd pages 1-282. Includes bibliography,list of figures and tables, used a Bizhub 250 Scanner to pdf format (OCR) 57pages contain figures in color.Digitized at 300 dpi 24-bit Color to pdf format (OCR),used a Hp Scanjet 8250
ENGLISH ABSTRACT: Ecosystems and natural water sources are constantly under threat from pollutants and all efforts should be made to minimise polluting factors. In the last decade growing concern has been expressed with regard to the environmental threat posed by wastewater produced by wineries and distilleries. Research into winery wastewater commenced in the early nineties mainly in Australia and France. These investigations characterised winery wastewater, indicating a large diversity in quality and quantity between wastewaters emanating from wineries. Owed to changes in South African legislation, in conjunction with an augmented environmental awareness, the need for an environmental assessment of wineries became apparent. In South Africa, research of this nature had not yet been conducted. Previous research on winery wastewater treatment employed mostly biological technologies, with success but also shortfalls. In South Africa the majority of wineries are located in the Western Cape Province, several within the same water catchment area. Wineries may produce approximately 1 to 10 litres of wastewater per litre of wine produced, which are turbid and acidic and typically contain high levels of organic compounds (thus oxygen deficient), and suspended material. Usually these wastewaters are irrigated onto land, in close proximity to natural water resources. The pollution of water tables and down-stream water sources may occur. The quantification, qualification and treatment of this type of wastewater are addressed in this study. Winery wastewater produced from the predominantly red wine producing Rupert and Rothschild Vignerons, served as case study for a two-year wastewater audit strategy. The most common analyses performed on winery wastewater include the Chemical Oxygen Demand (COD), suspended solids (SS), pH and turbidity. A thorough analysis in the form of a comprehensive audit was performed on the water and vinification processes. This allowed for an accurate determination of contamination sources and properties. The audit entailed a designed sampling protocol, the format of which was tailored as an initial environmental assessment for the development of an Environmental Management System (EMS) unique to Rupert and Rothschild Vignerons. The EMS includes projected future objectives for wastewater quality (COD, SS, pH, turbidity), as well as an environmental policy. In order to reach the proposed quality objectives, a suitable wastewater treatment system must be installed. The efficiency of the treatment system present at Rupert and Rothschild Vignerons was evaluated and piloted the investigation of physico-chemical treatment technologies. Research into the applicability of induced sedimentation (coagulation) and chemical oxidation (ozone) was the first of its kind for winery wastewater as substrate, and provided an interesting dimension in the sense of pragmatic and economic feasibility. Dissolved and suspended particles present in winery wastewater do not settle by gravity alone, thus requiring sedimentation agents (coagulants). Benchscale experiments were conducted employing four types of pre-polymerised metal salt coagulants (polyaluminium chloride). Successful sedimentation of turbidity inducing compounds (up to 98 %) and suspended solid fractions (up to 92%) was achieved. These coagulants are highly suitable for the treatment of winery wastewater since the investigation showed that they are effective over a broad pH and dosage range. In addition, rapid sedimentation rates were observed, favouring thickener design economy. Ozone is a potent oxidising agent, and has been reported to increase the biodegradability of dissolved organic compounds and result in the decolouring of wastewaters. Ozonation is highly pH dependent, with hydroxyl radical activity dominating at alkaline pH. In the majority of gas-liquid contacting systems, the kinetics of the heterogeneous reaction is not limited by the chemical reaction rate, but by the transport of ozone to the liquid phase. To compensate, the ozone concentration in the gas phase is increased. Coupled to the primary investigation on the applicability of ozone treatment for winery wastewater, thus emerged a secondary investigation into an enhanced mass transfer system, realised by the use of impinging stream technology. The ozone transfer in a conventional bubble-column was compared to that of an impinging-stream jet-reactor. The latter significantly improved the ozone transfer to the winery wastewater, resulting in the rate-limiting step being the chemical reaction rate. Ozonation resulted in the increased biodegradability of the winery wastewater, and complete colour and odour elimination. Concerning jet-reactors, the principal importance lies in the substantial reduction in the initial ozone concentration requirement, thereby rendering the process more economically feasible. Following the investigation of the wastewater dynamics, the determination of eco-toxicology during irrigation should be conducted in future. When considering induced sedimentation, further studies should be directed towards ascertaining the most economic yet efficient dosage of the coagulant. Similarly, a study concerning the economic viability of ozone efficiency should be realised in terms of the energy requirements for both ozone generation and the operation of jet-reactors. Although the jet reactor poses a benefit for enhanced mass transfer, the essential criterion concerning residence time in the reactor must be addressed for positive results. Since no single solution exists for the treatment of winery wastewaters, the application of the considered technology must be carefully selected and incorporated in a treatment design; the two foremost criteria for selection being efficiency and economy.
AFRIKAANSE OPSOMMING: Ekologiese stelsels en natuurlike waterbronne word gedurig bedreig deur besoedeling, dus moet ten aile tye gepoog word om besoedeling te minimiseer of te voorkom. Gedurende die laaste dekade is al hoe meer kommer uitgespreek oor die besoedeling van afloop water afkomstig van wyn en spiritualiee-vervaardiging. Navorsing aangaande wynafloopwater het ontstaan in die vroee negentigs, hoofsaaklik in Australie en Frankryk. Hierdie navorsing het gelei tot die karakterisering van wynafloopwater, en die uiteenlopendheid van hierdie water aangaande die kwaliteit en kwantiteit tussen kelders, is aangetoon. As gevolg van veranderinge in die SuidAfrikaanse wetgewing, asook 'n groeiende bewuswording van omgewingsake, het die noodsaaklikheid van omgewings impak-studies vir wynkelders na vore getree. Tot op hede is navorsing van hierdie aard nog nie in Suid Afrika gedoen nie. Vorige navorsing op die behandeling van wynafloopwater het meestal biologiese tegnologiee behels, met 'n mate van sukses maar ook met tekortkominge. Die meederheid wynkelders in Suid Afrika is in die Wes-Kaap gelee, baie binne dieselfde opvanggebied. Wynkelders kan tussen 1 tot 10 liter afloop water produseer per liter wyn geproduseer. Hierdie afloop het tipies 'n hoe konsentrasie organiese stowwe (is dus arm aan suurstof), is troebel en suur, en bevat gesuspendeerde materiaal. Gewoonlik word die wynafloop water besproei in die nabyheid van natuurlike waterbronne. Die besoedeling van watertafels en waterbronne kan dus plaasvind. Die kwantifisering, kwalifisering en behandeling van wynafloopwater word ondersoek in hierdie tesis. Die wynafloopwater van die hoofsaaklik rooiwyn produserende Rupert en Rothschild Vignerons, het gedien as proefstudie tydens 'n twee-jaar wynafloopwateroudit. 'n Deeglike analise in die formaat van 'n veelomvattende oudit is uitgevoer op die wynmaakproses en die waterafvoerstrome. 'n Akkurate bepaling van die oorsprong van waterkontaminasie, asook die eienskappe daarvan is bewerkstellig. Die oudit behels 'n spesifiek ontwerpte monsternemingprotokol, waarvan die formaat geformuleer is om te dien as 'n beginpunt vir die ontwikkeling van 'n Omgewingsbestuurstelsel (08S), uniek vir Rupert en Rothschild Vignerons. Hierdie 08S sluit toekomstige doelstellings vir die kwaliteit (chemiese suurstofbehoefte, gesuspendeerde vaste stowwe, pH, turbiditeit) van wynafloopwater in, asook 'n omgewingsbeleid. Die installering van 'n waterbehandelingsisteem moet geskied om te voldoen aan hierdie voorgestelde doelstellings. Die effektiwiteit van die huidige behandeling sisteem teenwoordig by Rupert en Rothschild Vignerons is geevalueer en het gelei tot navorsing oor fisieschemiese behandelingstegnologiee. Navorsing aangaande die toepassing van geinduseerde sedimentasie (koagulasie) en chemiese oksidasie (osoon), is vir die eerste keer toegepas op wynafloopwater, en het interessante gevolge in 'n pragmatiese en ekonomiese sin. Opgelosde en gesuspendeerde partikels teenwoordig in wynafloopwater sak nie onder normale gravitasie uit nie, en dus word die toediening van sedimentasie-induserende middels benodig. Eksperimente is in die laboratorium uitgevoer met vier verskillende gepolimeriseerde metaalsoutkoagulante (poli-aluminiumchloriedes). Dit het gelei tot die effektiewe sedimentering van stowwe wat troebelheid (turbiditeit) veroorsaak (tot 98 %) en ook gesuspendeerde stowwe (tot 92 %). Dit is gevind dat hierdie tipe koagulante hoogs geskik is vir die behandeling van wynafloop water, aangesien hulle effektief is by 'n wye pH- en doseringsreeks. Die uitsaktempo is vinnig, wat dus die ontwerp van 'n uitsaktenk (verdikker) ekonomies maak. Osoon is 'n sterk oksideermiddel, terwyl talle verslae aandui dat dit die biologiese ontbinding van opgelosde stowwe verhoog en die ontkleuring van afloopwaters tot. gevolg het. Osonering is pH afhanklik; by alkaliese pH oorheers die werking van hidroksielradikale. In die meerderheid gasvloeistofkontaksisteme word die kinetika van die heterogene chemiese reaksie nie beperk deur die intrinsieke reaksietempo nie, maar deur die vervoer van osoon na die vloeistoffase. Om te kompenseer hiervoor, word die osoon konsentrasie in die gasfase verhoog. Gekoppel aan die primere ondersoek aangaande die toepasbaarheid van osoonbehandeling op wynafloopwater, het 'n tweede ondersoek onstaan aangaande verhoogde massa-oordragssisteme deur die gebruik van hoeintensiteit spuitreaktore. Die osoonoordrag in konvensionele borrelkolomme is vergelyk met die van 'n hoe intensiteit spuitreaktor. Laasgenoemde het die osoonoordrag na die wynafloopwater aansienlik verhoog, met die gevolg dat die chemiese reaksie die beperking op die reaksie tempo geplaas het. Osonering het die biodegradasie van die wynafloop water verhoog, asook die kleur en reuk verwyder. By die spuit-reaktor Ie die belangrikheid daarin by die aansienlike veriaging in die aanvanklike behoefte aan osoonkonsentrasie, derhalwe is hierdie oordragsisteem meer ekonomies. Na afloop van die ondersoek op die dinamika van wynafloopwater, moet die ekotoksisiteit gedurende besproeiing bepaal word vir toekomstige doeleindes. Indien ge"induseerde sedimentasie verlang word, kan verdere studie gedoen word om die mees ekonomiese dosis van die koagulant te bepaal. Ooreenstemmend, moet die ekonomiese lewensvatbaarheid van die osoon effektiwiteit bepaal word ten opsigte van die energiebehoefte van beide die osoongenerasie en die werking van die hoe-intensiteit spuitreaktor. Alhoewel die spuitreaktor verhoogde massa-oordrag bewerkstellig, moet die effek van die residensietyd in die reaktor inag geneem word word ten einde positiewe resultate te verkry. Geen enkele oplossing bestaan vir die behandeling van wynafloop water nie, derhalwe moet die toepassing van die beoogde sisteem versigtig gekies word en ingesluit word in die ontwerp van 'n behandelingsisteem; die twee vernaamste maatstawwe is ondermeer effektiwiteit en ekonomiese aspekte.
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