Treatment of tea industry wastewater using a combined adsorption and advanced oxidation process

Tea, produced from the evergreen plant, Camellia Sinensis, is the most widely consumed beverage in the world after water. Although tea processing has now diversified into various speciality end products such as instant, white, oolong, iced, flavoured, and various blends, the most abundantly produced tea product in the world is fermented black tea. Black tea production is essentially a “dry” process, as no water is used at any of the production process steps. However liquid waste is generated due to the use of water for cleaning process equipment and factory premises. The waste exits the factory as coloured liquid effluent that must be treated before being discharged into rivers, lakes and other fresh water bodies. This paper presents findings of a study carried out to evaluate the performance of a combined adsorption and advanced oxidation process in removing colour from tea industry wastewater. The variables explored were the effects of sorbent mass, oxidant dosage, solution pH, agitation rate and temperature, on the decolouration of tea industry effluent. The results indicate that the combined adsorption and advanced oxidation is most effective at pH 3 wherein the effluent colour was reduced from 478 Pt-Co colour units to 8 Pt-Co colour units. The latter meets the NEMA recommended limit for discharge of colored effluents