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Pilot Scale Treatment of Table Olive Brines
Expanded Title:The pilot-scale system was designed, constructed and operated for 6 months during which data was collected and analysed; the yields and productivity of the process were established, and the economics of the treatment process were evaluated. Operation of the pilot plant has demonstrated that the technology is effective for treating such highly polluted brine wastewaters. The membrane was able to satisfactorily separate the high Mw phenolic components from the waste stream resulting in clear brine stream that was then sent to the chromatography system; this was able to produce a purified brine stream for recycle, whilst retaining the antioxidants for recovery. With the relatively small scale of the equipment used for the pilot plant, it was possible, on average, to process a 1 kL batch of wastewater per week, depending on the variable characteristics of the feed. Approximately 50 – 75% of this feed could be recovered as purified brine for recycling, while an additional ~300 L of fresh water was used for backwashing the membrane system and processing the chromatography column. Approximately half of this fresh water usage was also recovered for recycle. An average of 360 g of antioxidant product was produced per 1 kL batch of wastewater processed. The operational cost of production at the current level was around R20 per gram of antioxidant in the form of a crude extract, with a corresponding zero cost for the treatment and recovery of the wastewater. There is scope for significant improvement of the throughput, yields and productivity of the plant by using continuous (overnight) and simultaneous operation of the membrane and chromatography systems, as well as various modifications that can be made to improve the overall process. The majority of the objectives were achieved. Yields and productivity of the system were, however, lower than anticipated for 2 main reasons: firstly, throughput of the membrane system was lower than anticipated due to high suspended solids concentrations in the feed and subsequent fouling of the membrane. This can be improved by installing a pre-filter for the wastewater before membrane processing. Secondly, yields from the chromatography column could be improved by using pure ethanol for elution (denatured ethanol was used during this project), and the aspect ratio of the column needs to be changed (longer and thinner), to achieve a more uniform flow distribution through the column. Nonetheless, the system may be financially viable even at pilot scale. The system would need to be scaled up by a factor of 10 – 20 to treat all the brine emanating from the farm where the pilot scale studies were performed. This does not imply scaling-up of the footprint of the treatment plant by the same amount, merely scaling-up of the unit operations accordingly. This could be possibly be achieved by increasing the footprint of the current plant by a factor of 3 – 4. A spin-out company is being formed to exploit the IP generated during the project and develop the process into a full scale treatment system. Thereafter it is intended to roll out the technology to other olive producers, and investigate other possible applications of the technology. The process is only feasible if there are value-added products to be obtained from a waste stream; if wastewater treatment alone is considered, it is expensive due to the high cost of the speciality membranes and the chromatography resin used.
Date Published:01/03/2013
Document Type:Research Report
Document Subjects:Wastewater Management - Industrial
Document Keywords:Technology
Document Format:Report
Document File Type:pdf
Research Report Type:Standard
WRC Report No:2010/1/13
ISBN No:978-4312-0389-5
Authors:Garcin CJ; Harrison STL
Project No:K5/2010
Organizations:Centre for Bioprocess Engineering Research (CeBER); Chemical Engineering Department University of Cape Town
Document Size:973 KB
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