Processing live-poultry can cause a significant environmental impact. The La Avicola live poultry-processing facility was packaging approximately 35,000 to 40,000 birds per day and was coming under fire for not adhering to the latest governmental environmental regulations.
The process waste water from various stages of production (hot and cold) flowed into a series of clay-lined, stagnant basins then ultimately discharged into the nearby stream.
THe raw waste water was far from clean:
- Total Suspended Solids (TSS) of 2712 mg/l
- Total Dissolved Solids (TDS) of 2612 mg/l
- Total Solids (TS) of 5324 mg/l
- Fats, Oils, & Greases (FOG) of 3464 mg/l
- Biochemical Oxygen Demand (BOD) of 8850 mg/l
- Chemical Oxygen Demand (COD) of 13,064 mg/l.
The stagnant basins had become caked-over with floating solidified grease, feathers and viscera. This floating mass atop the basins had become a perfect nesting site for other disease-carrying vectors.
Recently adopted government guidelines demanded an immediate 80% reduction on each element (TS, FOG, BOD, and COD) before discharging into the nearby stream.
The solution was to develop what was essentially a functioning primary waste water treatment system on site. Full-diameter basin headers were installed for both influents and for the discharges; this rectified any short-circuiting in the basin.
The header system also controlled basin levels, maximizing holding capacities. The primary basin was converted to an aerobic treatment basin by installing submerged eductor nozzles. The intake was positioned to recirculate the primary basin while discharge nozzles served to provide subsurface aeration and air flotation.
A minor amount of aeration was installed in the third basin to further reduce BOD and COD before ultimate discharge.
The final task was to introduce high concentrations of specially selected bacteria to reduce the various wastes. The bacteria (containing both aerobic and anoxic species) were slowly fed into the waste water influent to the primary basin.
The treated waste water characteristics had been reduced as follows:
- TSS of 78 mg/l (97% reduction)
- TS of 1092 mg/l (79.5% reduction)
- FOG of 104 mg/l (97% reduction)
- BOD of 222 mg/l (97.5% reduction)
- COD 290 mg/l (97.8% reduction)
Within 8 months, the surface cake had liquified and the flow dynamics through the series of three basins allowed 12 to 14 hours extended retention for necessary treatment.
