Brewery effluent sludge characterization and dewatering to increase potential water recycling capabilities

Abstract

In this study various coagulants and flocculants were tested for optimum removal of COD from brewery wastewater. The coagulants used were ferric chloride and an organic coagulant mixture obtained from the brewery company. The flocculants used were a cationic flocculant (Genesys’ genefloc, polyquaternary amine), an anionic flocculant (Senfloc 5210), a non-ionic flocculant (Senfloc 5330) and a cationic acrylamide copolymer in aqueous dispersion (Brewery flocculant) for comparison. The organic coagulant mixture in aqueous solution was more effective than the ferric chloride at the same optimal dosage of 25 ppm. The ferric chloride and organic coagulant mixture used alone achieved COD removal efficiencies of 32.7% and 48.5% at a pH of 5.65 respectively while their performances for turbidity removal at pH 5.65 were 63.3% and 91.9% respectively. The best results were achieved when using the ferric chloride in combination with the cationic acrylamide copolymer in aqueous dispersion (Brewery flocculant) at an optimum dosage of 30 ppm and when using the organic coagulant mixture in aqueous solution in combination with the cationic acrylamide copolymer in aqueous dispersion (Brewery flocculant) at an optimum dosage of 10 ppm. When using ferric chloride in combination with the cationic acrylamide copolymer in aqueous dispersion (Brewery flocculant) and the organic coagulant mixture in aqueous solution in combination with the cationic acrylamide copolymer in aqueous dispersion (Brewery flocculant), COD removal efficiencies of 79.6% and 78.2% at a pH of 5.85 respectively was achieved, while they exhibited similar performance for turbidity removal at pH 5.85 of 99.7%. The optimization tests carried out in this study have allowed to improve the understanding of turbidity and COD removal mechanisms and achieved lower dosages of coagulants and flocculants for better treatment, therefore suggesting a more economical approach. Comparing the achieved results with the standard disposal values, it can be seen that the results gathered in this study complied to the values of the standard disposal values. This means that the quality of the treated water in this study complies with the environmental protection laws and will enable the brewery to dispose the treated water into the environment and municipal sewer systems