Contamination of aquifers by nitrates, due to the excess of fertilization in agriculture and improper wastewater management (discharge of untreated sewage into waters or ground), is a recurrent problem throughout the world. Complete elimination of infiltrating nitrates is seldom possible. Most of the commonly known technologies for nitrates removal are expensive to install and operate.

In 2000, the Management of the Wierzchowisko Drinking Water Utility had to find a solution to the increased nitrate content in raw water.

Use of Filtralite® Pure in a biological filter is the best solution.

In 2006, Nitrate Removal Facility using Filtralite® Pure as the carrier media was built.

The Nitrate Removal Facility consists of three parallel technological lines - a total of 27 tanks, of which the most important 15 tanks contain Filtralite® Pure media. The filters are backwashed every 24 hours.

Biofilters are used for biological denitrification. The process involves naturally occurring heterotrophic bacteria, that develop on the Filtralite® Pure media in form of a biofilm.

Nitrate concentration in raw water exceeds 65 mg/L and is reduced to less than 15 mg/l after biological removal.

The full treatment process also involves aeration, flocculation, filtration on dual media Filtralite® Mono-Multi solution and final filtration with activated carbon.

The plant treats 250 m3/h on average, but it has been designed for a maximum of 750 m3/h.

"Only half of the raw water volume goes through the nitrate biological removal facility before final disinfection by ozone treatment. Biological denitrification is highly effective. However, it is essential for the microorganisms to have the stable conditions maintained. On ground of periodic filter media inspections we confirm, that Filtralite is a high quality product - this grants the proper operation of the treatment process." - DWTP Manager

"During 12 years of operation we have mastered the use of this outstanding nitrate removal technology. We run a stable process in biofilters with Filtralite. This technology does its job well. " - Head Technologist

More details are available here.