Waste water is pumped underground to lifting stations where it is chemically treated and sent, either through the sewer system or by road, to treatment centres for processing and separation.
Are used in urban areas to transport the raw sewage to minor treatment centres for primary treatment; or on to Waster Water Recycling Centres for processing.
Lots of things get into the sewers that shouldn't. Cans, plastic bags, nappies... even false teeth and wallets.
Our next job is to take out all the solids. We do this by pumping the water into large, deep tanks called sedimentation tanks. Here the heavy solids are allowed to settle out and then taken away for further treatment. This leaves us with water that has a lot of invisible solids that we need to take out in the next stage.
Chemicals and air are pumped through the sludge to activate the bacteria within it causing them to degrade the remaining pathogens.
The waste water is then passed over a biological filter where it is exposed to billions of bacteria which attack the remaining solids and pathogens breaking them down and straining the sludge.
Gravity feeds the water through secondary clarifiers allowing bacteria to continue to clean the water to a drinkable level.
Clean water is put back into the local streams and rivers.
The water is then pumped to an outfall at selected site in the local area.
These plants operate a thermal hydrolysis system which treats the sludge through four biological processes. The sludge goes through a pre treat phase and is brought up to 165oC; the whole process takes a minimum of 13 days to treat. At which point the Biosolids are ready for land.
This process achieves the same out comes as the Cambi Systems but uses Enzymic Hydrolysis. The sludge moves through 5 digesters to pasteurise and treat the now Biosolids. It does this by activating the sludge keeping it at a constant and optimum temperature of 40oC before increasing the temperature to kill all remaining biological processes. Its at this point the Biosolids are ready for land.
This is a hybrid system patterned by Anglian Water. It treats the sludge both Thermophilicly and Mesophilicly under the banner of ‘Biological Hrydrolysis’. The sludge is activated and pasteurised through three tanks where the temperature reaches 55oC before moving on to more conventional Anaerobic Digestion tanks for up to 13 days. The advantages of this system are increased ‘solids’ destruction and treating the Biosolids to an enhanced standard. This way of doing it also helps minimise odours form the Biosolids!
nutri-bio operates three of the most advance types of Anaerobic Digester in the UK. Which treat our Biosolids to a conventional standard; this requires them to be 99% pathogen free. They are though capable of reaching the standards outlined under the enhanced status, 99.9999% pathogen free. To put that in to context that’s as clean than your bleach wiped counter tops!