Company ProfileCase Study: Abattoir—Northampton, UK
Increased feed rate for 1,000 cattle/day and additional sheep and pigsThe Problem
EversTech was called in to redesign the existing effluent treatment plant to cope with an increased feed rate and effluent loading, and to maximize resource recovery.
The treatment plant area was also to be moved out to the edge of the factory site in order that the existing plant area could be used for an expansion of production. Proposed changes in production, incorporating a pet food division and a hide store (with high salinity effluent), meant that we also needed to develop bacterial formulations that were tolerant of up to 2% salinity.
The existing plant consisted of a pre-screening area, an oxidation ditch, anaerobic digestion, secondary activated sludge and reed beds. Ammonia was a constant problem and the effluent quality rarely complied with government standards.The EversTech Solution
EversTech designed a replacement treatment plant which retained the screening system and then pumped all effluent to the new site.
Pre-digestion with bioaugmentation hydrolyzed all grease and fats, and a Helixor aeration system with clarifiers and sand filters removed the remainder of the organic matter as COD/BOD, as shown in the table below. With bio-augmentation, a much more complete and rapid aerobic digestion was achieved and further addition of bio-cultures ensured full nitrification and an odorless biomass suitable for marketing. The existing reed beds were no longer necessary and were eliminated.
Average Analysis of Plant Effluent
| Parameter | Raw Waste | Final Effluent |
| pH Value | 6.23 | 7.1 |
| COD | 20000 | 20.0 |
| BOD | 10150 | 5.0 |
| Suspended Solids | 17560 | 5.0 |
| Volatile Suspended Solids | 15623 | 2.0 |
| Total Nitrogen | 527.10 | 2.0 |
| Phosphate | 5.84 | NIL |
| Potassium | 138.00 | 1.0 |
| Grease & Oils | 7.153 | NIL |
| Total Organic Carbon | 876.00 | 0.5 |
The plant is fully automated and monitored through a PLC System.
Financial and Environmental Benefits
Capital Cost was £1.5 million and sales of the biomass as organic fertiliser are in excess of £400,000 per year. Further development of the site will incorporate anaerobic digestion and energy generation for site use and for sale.