Individual Wastewater Treatment


Discharge of house hold wastewater has always been a problem in rural area’s, not being connected to the main sewer. The upcoming EU Water Framework Directive (WFD) expands the scope of water protection to all waters and sets clear objectives that a “good status” must be achieved for all European waters by 2015 and that water use be sustainable throughout Europe.

Standard high demands for individual wastewater treatment systems in E.U. countries are discharges containing 20 mg/l BOD and 30 mg/l SS. DMT has designed two types of Individual Wastewater Treatment systems (IWT)

The new standard system for removal of pollutants from household waste streams is meeting the strictest requirements of 5/5. Optional is the DMT_IWT system to meet the standard requirements of 20/30 (BOD/SS).

The process description of the DMT IWT system capable to give a discharge of 5/5 is given below:
First step; the influent flows into the Pre-settlement tank, where large solids settle.
Second step; Wastewater flows into the Denitrification and oxidation tank, where COD, BOD and nitrogen is removed.
Third step; the activated sludge flows into the first clarifier compartment. In here, the activated sludge is recirculated to the denitrification compartment.

Designed recirculation and denitrification prevent sludge floatation and ensures the clean effluent of 5 mg/l O2 BOD and 5 mg/l SS. The second stage in the clarifier tank acts as a backup system.
The oxidation, as well as the recirculation, are achieved by use of the same blower, reducing the amount of needed energy and mechanical parts.