Characterisation of aerobic biotreatment of meat plant effluent : a thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy in Environmental Engineering, Institute of Technology and Engineering, Massey University
This study investigated the bio-kinetics of a meat-processing wastewater in an activated sludge system. The main pollutant loading of the wastewater under investigation was characterized as 1350 mgCOD/L, 70 mgNH4-N/L, and 127 mgTKN/L in average. Ihe respirometric method and aerobic batch methods were used to evaluate the biodegradability and the kinetics of carbon removal and nitrification of meat-processing wastewater in an activated sludge system. The readily biodegradable COD accounts for 15~17 % of the COD in meat-processing wastewater, while the inert portion, including soluble and particulate, accounts for another 10% of the COD. Approximately, 1/3 of the meat-processing wastewater composition is in soluble/fine colloidal form and the remaining 2/3 is in particulate form. For heterotrophos growing on soluble meat-processing wastewater, the determined values of kinetic constants for carbon removal were 0.63 mgcellCOD/mgCOD for the observed COD based yield coefficient (YH), 0.40 mgVSS/mgCOD for the observed mass (VSS) based yield coefficient (Y
O), 1.4 for COD/VSS ratio, 3.3 day-1 for the maximum specific growth rate (μH MAX), and 10 mgCOD/L for the half-saturation constant (Ks). The death-regeneration decay coefficient of heterotrophos (bH) was 0.38 ~ 0.49 d-1. For heterotrophos growing on unfiltered meat-processing wastewater, the relationship between So/Xo and the observed corresponding specific growth rate (μ, d-1) was found to fit a Monod type function. The maximum specific growth rate of heterotrophos in unfiltered meat-processing wastewater was determined as 9 d-1, while the half-saturation constant was found to be 22. In regard of nitrification, the maximum specific growth rate of autotrophos in soluble meat-processing wastewater was 0.56 ~ 0.71 d-1.