Abstract
Slaughterhouse plants, especially meat and poultry products (MPPs), generate significant quantities of wastewater during the slaughtering process and the cleaning of machinery. The handling and final disposal of wastewater from the slaughterhouse is a public and environmental health issue due to its pollution potential. The monitoring of three full-scale buffalo meat-based abattoir effluent treatment plants (ETPs) to remove organic matter and nutrients was conducted at three separate sites in India. Rotary and static screens, an equalization tank, a dissolved air flotation (DAF) system, aeration tanks, and clarifiers were the component unit operations/processes of the wastewater treatment systems. All the treatment plants were operating at an average flow rate of 254 m
3
/d Meem Agro (designed capacity 500 m
3
/d); 427 m
3
/d Al Noor (designed capacity 500 m
3
/d), and 353 m
3
/d International Agro Foods (IAF) plant (designed capacity 750 m
3
/d) for the treatment of slaughterhouse wastewater. The Al Noor and Meem Agro’s ETP consisted of a DAF unit working at the surface-loading rates of 5.7 and 1.48 m3/m
2
h, respectively, applied during the analysis to the DAF system, resulting in 46.5 and 56.8% efficiencies of O&G and SS removal. The ETP of Al Noor and Meem Agro and IAF was loaded at an organic loading rate of 276 kg COD/day, 746 kg COD/day, and 629 kg COD/day, respectively. Performance of ETPs showed that the efficiency of total COD, total BOD, and TSS removal was 97, 98, and 99%; 94, 94, and 93%, and 95, 98, and 99% for Al Noor, Meem Agro, and IAF plants, respectively. The treatment plants’ efficiencies in all three plants for the removal of organic matter surpassed the effluent discharge level (as per Indian standards). Still, it is concluded that the ETPs need to be upgraded by incorporating the advanced wastewater treatment methods for the removal of nutrient concentration from treated effluents.