A Critical Review on Processes and Energy Profile of the Australian Meat Processing Industry

This review article addresses wastewater treatment methods in the red meat processing industry. The focus is on conventional chemicals currently in use for abattoir wastewater treatment and energy related aspects. In addition, this article discusses the use of cleaning and sanitizing agents at the meat processing facilities and their effect on decision making in regard to selecting the treatment methods. This study shows that cleaning chemicals are currently used at a concentration of 2% to 3% which will further be diluted with the bulk wastewater. For example, for an abattoir that produces 3500 m(3)/day wastewater and uses around 200 L (3%) acid and alkaline chemicals, the final concentration of these chemical will be around 0.00017%. For this reason, the effects of these chemicals on the treatment method and the environment are very limited. Chemical treatment is highly efficient in removing soluble and colloidal particles from the red meat processing industry wastewater. Actually, it is shown that, if chemical treatment has been applied, then biological treatment can only be included for the treatment of the solid waste by-product and/or for production of bioenergy. Chemical treatment is recommended in all cases and especially when the wastewater is required to be reused or released to water streams. This study also shows that energy consumption for chemical treatment units is insignificant while efficient compared to other physical or biological units. A combination of a main (ferric chloride) and an aid coagulant has shown to be efficient and cost-effective in treating abattoir wastewater. The cost of using this combination per cubic meter wastewater treated is 0.055 USD/m(3) compared to 0.11 USD/m(3) for alum and the amount of sludge produced is 77% less than that produced by alum. In addition, the residues of these chemicals in the wastewater and the sludge have a positive or no impact on biological processes. Energy consumption from a small wastewater treatment plant (WWTP) installed to recycle wastewater for a meet facility can be around $500,000.