WWTP Sallek Valley:advanced waste water treatment with upflow biofiltration.
The aerated upflow biological filtration (biofiltration) is a technology which is today successfully used in more than 500 European wastewater treatment plants. Among this, the one of Sallek Valley, in Slovenia, differs by a two stage biofiltration and a part-recirculation of sludge from thickener to increase the COD concentration needed for denitrification. This process allows an advanced denitrification- nitrification in a very compact way and low operation costs. The results of the wastewater treatment plant will be presented and commented in order to prove the high efficiency of the process.