Submitted to: Poultry Science Meeting
Publication Type: Abstract Only
Publication Acceptance Date: April 2, 2012
Publication Date: July 9, 2012
Citation: Kiepper, B.H., Buhr, R.J., Walker, J.M., Bourassa, D.V., Brooke, C.A., Zhuang, H. 2012. Impact of broiler slaughter scalding method on processing wastewater stream. Poultry Science Meeting. 91(suppl. 1):69. p.25. Technical Abstract: The impact of broiler scalding method on the resulting processing wastewater stream was evaluated. On 3 separate days, 5 to 7 wk old broilers were subjected to a 10 h feed withdrawal, cooped, transported, weighed (live weight), shackled, and then stunned (14.5 V DC, 500 Hz for 10 s) and bled (2 min) in 6 sequential batches (n=16/batch). Weight selected broilers (within 300 g) were subjected to either hard (60ºC for 1.5 min) or soft (52.8ºC for 3 min) scalding in an aerated 3-tank sequential configuration (740 L/tank). Prior to each scalding treatment, a 1 L sample of scalder make-up water was collected to determine potable water background values. Following the 3-batches for each scalding treatment, a 1L sample of scalder wastewater was collected from each of the 3 scalding tanks. All samples were stored at 4oC and analyzed for concentration (mg/L) of chemical oxygen demand (COD), total solids (TS) and total volatile solids (TVS). Resulting concentration data were used to calculate a corresponding wastewater loading value in grams per kilogram of live weight (g/kg-lwt). Post-feed withdrawal mean live weights for the 3 days were 2.924 kg (d 1), 1.942 kg (d 2), and 3.158 kg (d 3). The overall mean TS wastewater load produced during soft scald treatment (1.337 g/kg-lwt) was significantly (P=0.05) higher than hard scald (0.717 g/kg-lwt). The soft scald treatment also produced numerically but not significantly greater TVS (1.091 vs 0.609 g/kg-lwt) and COD (0.958 vs 0.755 g/kg-lwt) wastewater loading than hard scald. Scald tank position within the 3-tank sequence also had an impact on wastewater loading. In all treatments combined, the first scald tank had significantly (P=0.05) greater COD (0.551 g/kg-lwt) and TVS (0.492 g/kg-lwt) mean loading than the second and third scald tanks, which were not significantly different from each other. In terms of TS, the first scald tank loading (0.584 g/kg-lwt) was significantly greater than the third tank, but not the second scald tank. Results indicate that soft scalding of broilers (52.8ºC for 3 min) has a greater impact on processing wastewater loading than hard scalding (60ºC for 1.5 min).