Recycling of poultry process wastewater by ultrafiltration

Poultry processing plants use relatively high amount of water with an average consumption of 26.5 L/bird during primary and secondary processing of live birds to meat. The used water contains proteins, fats, carbohydrates from meat, blood, skin and feathers, resulting in much higher biological oxygen demand (BOD) and chemical oxygen demand (COD). Hence the processors are required to remove majority of the soluble and particulate matter in the wastewater prior to discharge from the plant, Treatments for poultry wastewater include screening, diatomaceous earth filtration, ozonation, and chlorine dioxide. Food safety and inspection service regulations allow reconditioned water to replace potable water in prescribed ratios. Recycling of poultry wastewater by ultrafiltration improves the quality of recycled water and provides solution to water resource limitations. Ultrafiltration is basically a pressure-driven process that separates on the basis of molecular diameter. Membrane bioreactors (MBR)that integrate biological degradation of waste products with membrane filtration are also quite effective in removing organic and inorganic contaminants as well as biological entities from wastewater. Value added products like crude proteins could be separated through ultrafiltration from poultry wastewater, subsequently reducing the chemical oxygen demand. Ongoing research in membrane separation techniques involves exploration of new membrane materials and of new module design configurations to address issues of membrane fouling and treatment of waste streams containing high suspended solids or viscous wastes. Industrial relevance: Poultry processing plants use large volumes of water at different stages of the process due to set policies regarding the pathogen reduction requirements in the broiler meat. Recovery of process wastewater benefits the plant by reducing fresh water demand, wastewater volume and energy consumption. Microbial safety is the primary concern in reconditioning of process wastewater. Proteins and fats which come from carcass debris and the blood are the major pollutants in the wastewater. These materials are of high nutritional value and should be recovered. The proteins and fats are difficult to harvest by conventional procedures. From an environmental and economic point of view, ultrafiltration is an efficient technique to recondition wastewater and to recover proteins and fats from it Importantly, this technology addressed the water quantity and quality issues that have been raised in this industry by reducing primary water use and electrical energy. Though the capital costs of ultrafiltration are higher, their life cycle costs are comparable with conventional treatments. Further. foot print of ultrafiltration could be 30-50% of conventional filters with less consumption of chemicals. Hence this paper focuses upon the potential for the use of ultrafiltration membrane processing for recycling poultry process wastewater and recovery of value added products. (C) 2008 Elsevier Ltd. All rights reserved.