Producer of cereals and cereal bars Deeside Cereals has invested in new wastewater treatment equipment to overcome the challenges it was facing with a problematic effluent.
The company first introduced a new dissolved air flotation (DAF) unit from Watermark, a division of WA Cooke group, to separate suspended solids and for the thickening of sludge. However, fats oils and greases (FOG) caused by ingredients such as chocolate, rape seed oil and lecithin at one point reportedly sent chemical oxygen demand (COD) up to 78,000.
Deeside Cereals safety, health and environment manager Karl Johnson said, “The DAF unit from Watermark has [brought] COD down to 6,000 initially. We wanted to make further improvements to our treatment regime to meet Dŵr Cymru Welsh Water strict compliance levels.”
With Watermark’s recommendation to use the AirJet from service provider Landia, the team decided to first take one on trial for its new 60m3 wastewater treatment tank to suspend the solids from Deeside Cereals’ effluent, according to Johnson. Comprising a 5.5kW chopper pump and a venturi nozzle, the low-energy AirJet can reportedly mix and aerate down to a water depth of approximately 7.5m, without the need for a compressed air supply.
Alistair Fielding from Watermark said that customers benefit from equipment as it also “offers the best possible value in total cost of ownership”. It had previously teamed up with Landia to help introduce a mixing system to handle wastewater at an expanding organic poultry producer in South Wales, UK. Here, the AirJet is said to eliminate the need for compressors, bottom-mounted diffusers and advanced controls.
Johnson added that it is challenging to treat and fulfil compliance obligations when sugary water used becomes entrained. “It took us a while for the AirJet and the DAF to harmonise, with some minor adjustments required around the length of time to aerate the trade effluent,” he said. “We found that it is easier to control the COD by only half filling our tank, but we always test it before discharge and if needs be, can aerate the effluent a little longer until it is below our compliance threshold.” The Landia pump needs a quick visual inspection each day to check on oil and the cereals producer team is setting up a service agreement for a twice-yearly maintenance check.