| Popis: |
SUMMARY Two experiments were conducted to model and predict the environmental impact of flume transport of broiler offal viscera on poultry processing wastewater (PPW) under controlled laboratory conditions. In experiment 1 (24 experimental flock broilers) and experiment 2 (120 commercial flock broilers) birds were randomly assigned to 4 treatment groups: short-bleed (60 s) and soft-scald (50°C), short-bleed and hard-scald (60°C), long-bleed (120 s) and soft-scald, and long-bleed and hard-scald. Birds were processed individually (experiment 1) or in groups of 5 birds (experiment 2). Each broiler was electrically stunned, decapitated, bled, scalded for 2 min, and defeathered. Each carcass was manually eviscerated and the individual viscera (experiment 1) or group of 5-viscera (experiment 2) were sequentially agitated in potable water for 1 and 3 min. The resulting viscera rinse PPW was sieved (500 µm) and analyzed for concentration (mg/L) of chemical oxygen demand (COD; experiments 1 and 2), total solids (TS; experiments 1 and 2), total suspended solids (TSS; experiments 1 and 2), total volatile solids (experiment 1), and total Kjeldahl nitrogen (experiment 1). A PPW load in grams per kilogram of live weight (g/kg lw ) was calculated for each concentration (mg/L) data point. Neither bleed time nor scald temperature played a significant role in the effect of viscera on PPW mass loading. However, viscera agitation duration did play a significant role in PPW mass loading. Commercial flock broiler mean PPW mass loadings (g/kg lw ) generated by 1 min of viscera agitation were 0.674 for COD, 1.160 for TS, and 0.111 for TSS. Mean loadings at 3 min of agitation were 1.007 for COD, 1.399 for TS, and 0.188 g/kg lw for TSS. |
