The Safety and Quality of Recycled Scald Tank Water from Commercial Poultry Processing, Treated Using a Ceramic Membrane System

Introduction: Poultry processing plants use large quantities of water and energy. With rapidly increasing consumption of chicken meat, processors are under greater strain to increase production in order to meet demand. Site-specific limitations on water consumption and discharge exist within current plants. This, in conjunction with the introduction of a carbon tax in Australia, has driven investigation of recycling water and energy within the plant to maximize processing efficiency.

Purpose: To determine if scald tank wastewater can be treated, using membranes, in a manner that maintains quality and safety, and recycled, reducing water and energy consumption.

Methods: A pilot plant, utilizing a 0.2 μm α-Al₂O₃ ceramic membrane, was used over nine months to treat screened scald tank wastewater via membrane filtration. Trials (4-16 h) were conducted in which concentrate and filtrate samples were collected and subjected to water quality analysis. The concentrate and filtrate were analyzed quantitatively for total viable count (TVC), total coliforms (TC), and Escherichia coli using the Tempo, and qualitatively for Salmonella. Total suspended solids (TSS) were analyzed using Australian Standard 3550.4:1990, turbidity was measuring using a turbidity meter and pH was measuring using a handheld pH probe.

Results: Treatment of scald tank wastewater reduced populations of E. coli from 5x10⁵ to <1 MPN/ml. Salmonella was not detected in any of the concentrate or filtrate samples. TVC was reduced by 2-4 logs. All water quality indicators (TSS, pH and turbidity) met Australian and major international water recycling guidelines.

Significance: Scald tank wastewater can be treated to allow recycling, reducing the environmental impact of chicken meat processing.