Micropollutants in the aquatic enviroment

MIKROFLOCK

Upgrading municipal sewage treatment plants with flocculation - filtration units by the use of activated carbon

By addition of activated carbon, micropollutants can be reduced to a certain degree from the liquid phase at sewage plants. Herewith, the inert COD in the effluent of the sewage plant may be significantly reduced. Many of the larger sewage plants in Northrhine-Westfalia are equipped with final filtration units, which may be used for this purpose: the construction already exists, the filter inflow shows no or only less particulate matter and an emission of loaded activated carbon into the receiving water is reliably avoided. In this R+D-project different technological approaches shall be investigated on their technical, operational and economical realisation in full scale at existing filter units in Northrhine-Westfalia. At Buchenhofen STP the dosing of powder activated carbon (PAK) into the submerge of one filter chamber and at Düren-Merken STP a change of the existing filter material against granular activated carbon (GAK) will be investigated. In addition, the dosage of PAK into the effluent of the final settling tank with a technical carbon separation prior to the filtration unit will be tested in laboratory and/or pilot scale. A technical scale test of this approach is considered as an option for an ongoing R+D-project. The investigations are completed by an assessment of different activated carbons prior to the testing. For constructional details two consultancies participate in the project. The results will be summarised in an praxis-orientated report. The report will also include an assessment for an implementation of the investigated approaches at other sewage plants with filtration units in Northrhine-Westfalia.