Ballyrashane Creamery had a high concentration of fat in waste water generated from the dairy’s milk and cream processing operations made the effluent treatment process less efficient. Maintaining excellent levels of effluent discharge compliance was very important to the site, so a solution for removing the fat, and eliminating its effect on the treatment process was required.
The Overall Objective
In addition to alleviating the treatment problems, the creamery was also keen to get some benefit from the recovered fat. Therefore a solution was required that did not involve use of process chemicals, and that could be easily incorporated into the existing treatment process without causing disruption to production.
A Siltbuster D25 packaged lamella DAF was specified, with the micro-fine air bubbles (white water) alone encouraging the fat to float to the surface of the unit, for removal by an automated mechanical scraper. Up to 20m³/hr of waste water is continuously fed through the unit, with removal of the fat making a tremendous difference to the efficiency of the effluent treatment process downstream.
The recovered fat from the DAF is then mixed with other sludges from the plant, before being pumped to the new offsite Anaerobic Digestion (AD) facility. Due to its high calorific value, it is ideal for producing energy. So the benefit of the site’s investment in the DAF was twofold – improving the effluent treatment process and helping to generate renewable energy.