IN THE SPOTLIGHT - 1-STEP® filter

Ultimate one step total effluent polishing filter for municipal wastewater

At present, removal of suspended solids, nutrients, heavy metals and organic micro pollutants from treated effluent of wastewater treatment plants requires successive conventional processes to be implemented at the WWTP, leading to high investment and operational cost.

The 1-STEP® filter, developed by Nijhuis Industries, Witteveen+Bos and Waternet, is an innovative compact fixed bed activated carbon filter operated at a relatively high rate downward flow combining four processes in one single additional treatment unit.

Besides removal of suspended solids by filtration, it performs excellently on nitrogen removal by simultaneous biological denitrification (using a selective carbon source), chemical phosphate and heavy metals removal (by coagulation and flocculation with a low dose of metal salt) and, if required, removal of organic micro pollutants by adsorption to the activated carbon.


Manager Innovation & Technology and 1-STEP® filter expert Wilbert Menkveld about the solution

“The Nijhuis 1-STEP® filter combines four treatment processes into one additional single treatment unit. The solution can be applied as comprehensive tertiary treatment of treated effluent for final polishing, advanced nitrogen and priority substances removal, and removal of phosphorous to a standard < 0.25 mg P/l. The 1-STEP® filter is easy to implement and extend since it can be added to existing wastewater treatment plants or function as a pre-treatment unit in treated effluent recycling facilities. For example, the Implementation of the 1-STEP® filter at Horstermeer WWTP resulted in 30 - 50% saving in investment and operational costs compared to conventional successive processes.”

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