Funding:

Project management / project work:

Situation:

The use of antiscalants (AS) in the treatment of drinking water by means of  reverse osmosis (RO) or nanofiltration (NF) is common practice in Germany. Various technical products are used in the approx. 90 plants, generally based on phosphonic acid, but also phosphorus-free AS based on polyacrylic acids. The authorised antiscalants are specified in the § 20 list of the Drinking Water Ordinance.

The predecessor project KonTriSol (BMBF/DVGW funding, project end 2023) identified acute problems with the use of AS in membrane filtration. Residual concentrations of antiscalants were found in permeates and drinking water from corresponding systems.

Additionally, problematic substances might be formed in downstream processes such as disinfection or activated carbon filtration from the substances that enter the permeate.. In the case of P-free products, there are indications that the active ingredient content with a small molecular mass is ineffective or can cause biofouling.

Solutions are being sought with regard to the respective product contamination of the AS, human toxicity and operational behaviour.

With the direct involvement of the UBA as a project partner, safe operational, regulatory and legal conditions for Germany are to be derived.

The specific objectives are as follows:

• Further development of analytics for the various types of antiscalants, among other things to clarify the extent of AS transfer into the permeate of the RO/NF
• Simplification of the analysis of AS by developing an "analytical test battery" so that simplified, cost-effective and rapid characterisations can be implemented
• Identification of safe and effective AS formulations (with regard to secondary constituents, membrane permeability, fouling potential in RO/NF, contamination potential in drinking water distribution)
• Investigation of so-called "green" antiscalants (not yet authorised in Germany) with regard to effectiveness and possible side effects
• Proposals for a legally compliant application via the technical regulations of the DVGW (W236) and the § 20 list of the TrinkwV