Black-water (sewage) treatment

 Sewage treatment involves taking wastewater from showers, wash hand basins, and toilets, treating it, and re-using it in certain applications.

2nd class water


Much of the water used by an enterprise does not need to be 1st class potable (drinking) water. Do you really need potable water to flush toilets with, irrigate plants, use in scrubbers, chillers, or wash vehicles with? Treated sewage effluent, also known as TSE or blackwater, can meet the water required in several applications, mainly toilets and irrigation. 


It is worth examining your enterprises operations to identify the quantity of water being consumed in these applications. Once you know the demand for 2nd class water, you can identify whether it can be met by treating sewage.


How can you treat sewage?


All domestic wastewater generated by an enterprise is funnelled into a treatment plant. The treatment plant consists of sedimentation tanks as well as tanks where bacterial treatment takes place. The most sophisticated of systems may include further state of the art treatment capable of producing 1st class (potable) water from the effluent.


To treat sewage a minimum quantity of 100m3 of wastewater needs to be generated per day. A space of at least 250m2 then needs to be available for the plant.


Costs involved in treating sewage


Treating sewage produces a cheap source of water, estimated at €0.90 per m3. Costs for equipment start at around €120,000 with a repayment period of around 5 year.


Online Self-Assessment Tool – is rainwater harvesting for you?


Our online self-assessment tool can evaluate the potential for treating sewage in your premises. The tool assumes that you will use treated sewage only for the flushing of toilets; however a more in-depth study could reveal other uses of treated sewage effluent. If you would like an indication of other uses book a water audit here.

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