The works has a population equivalent of 9,000, 5,000 of which comes from a nearby fish processing company and this is the root cause of the problem at the works. The works itself is conventional with the addition of a large plastic media filter. Due to the presence of large quantities of fish oils the plastic filter was failing to operate efficiently, causing the works to be 'at risk' and ultimately failing consent.

This photograph shows the thick crust of solidified oil on the surface of the plastic media inlet pump chamber before Bio-Selector installation

An initial survey was carried out to quantify the problem, and samples taken were analysed in our laboratory. A treatability study was carried out to identify which mixture of bacteria could be used to augment the indigenous bacteria and improve effluent quality. The results indicated that a mixture of Lipase-producing bacteria would have the greatest effect on the effluent quality.

On-site bio-augmentation is achieved by culturing the bacteria in breeder vessels and subsequently dosing high concentrations of actively-growing bacteria into the works. Greener Waste Ltd have a number of sizes of unit designed for different flows. In the case of this works a medium-sized breeder unit was used.

A Bio-Augmentation unit was installed at the end of January, two weeks later a change in the appearance of the primary tank effluent was observed. In the third week the pump chamber was starting to clear

• Bio-augmentation of a small works with two high-rate plastic filters
• The BioSelector
• The Greener Waste Filter Bed Cleaning Programme
• We are Greener Waste Limited
• The Greener Waste Solution
• Filter Bed Remediation
• Bio-augmenting ammonia removal across filter beds