Like many companies discharging liquid waste to sewer, we have to pre-treat the effluent from our cleaning process by using a Dissolved Air Flotation Plant, or DAF as they are known in the trade. The DAF plant then produces sludge, which we would then have to tanker away for off-site treatment, which is an exceptionally costly exercise.
Late in 2020 we took delivery of a Screw-type Sludge press following a 4 week trial of a pilot unit which had worked well. The Press takes the sludge we produce from the DAF plant and de-waters it using a bit of magic involving some polymer additive and a mechanical screw-press action. The results are astounding.
Water is removed from the sludge, leaving a “cake” which is then collected in a skip. This cake is then collected from site and taken to a processing plant where the waste is processed through an anaerobic digestion plant, producing bio-gas which is then converted into electricity. This process helps us keep our operating costs at an acceptable level and forms part of our environmental strategy for the reduction of carbon emissions, and the generation of green energy.