Waste Water Re-use

Waste incineration generates a high humidity flue gas that also contains contaminants due to fuel. Flue gas condensing is a cost-efective and ecological way to increase the boiler's district heat production. The condensate formed in flue gas condensation is with proper treatment usable to replace potable water as raw water. Due to the specific challenges of waste incineration, the Sofi process delivered does not discharge any water into the sewer.

FLUE gas treatment and flue gas dead-end

With the Sofi process (MF and RO) approximately 75% of the condensate is gained as makeup water for district heating. Treated condensate is solids free low conductivity (< 150 µS/cm) water. Reverse osmosis uses high temperature membranes with a maximum operating temperature of 85 ° C. This, in addition to water recovery, allows for heat recovery without extra investment in heat exchangers.

District Heating Network

In CHP plant, even a small amount of very fine particle contamination, e.g. magnetite below 1 µm, lowers the efciency of the heat distribution system and may result to uncertainty in measurement equipment. The solids are removed from side stream by automatic Sofi Filter unit.

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In Sofi Filtration’s solution the waste water is fed to a settling tank with a screw conveyor which removes the solids.

The overflow of the settling tank is pumped to Sofi Filter via a centrifugal pump. Due to the filter’s cross-flow design, part of the feed flows through the filter element and part returns to the process. In this application Sofi Filter is equipped with a 10 µm metal wire mesh element. The filtrate from Sofi Filter can be drained or reused. Sofi Filter reduces the amount of water in the settling tank and concentrates the solids so that they can be removed with the screw conveyor.