The Appital seawater desalination plant in Switzerland is located in Au-Wädenswil on Lake Zurich, about 20 kilometres south of the city of Zurich. It was commissioned in 1977 and has since produced around 60 million cubic metres of potable water. But time had taken its toll on a drinking water tank belonging to the plant such that it now required extensive rehabilitation..

Problems of soft water

The company Frei + Krauer AG, Rapperswil, which was entrusted with the planning, commissioned De Lucia Bautenschutz und Renovationen AG of Wädenswil to carry out the repairs. Since one of the reasons for the rehab is the particularly soft water in the region and its corrosive action on the concrete and reinforcement, the new mineral linings needed to offer permanent resistance to such media, which meant a Type-1 mortar had to be used.

MC’s new Type-1 mortar ticks all boxes

Due to the challenge posed by the soft water on the one hand and the planner's as well as the processor's extremely good, long-standing experience with the MC-RIM PW family on the other, they resorted to MC's Type 1 drinking water mortar MC-RIM PW 111, which was introduced in mid-2022 and was developed for the surface protection of wall and ceiling surfaces in drinking water tanks. From a hygienic point of view, the Type 1 classification of mineral coatings sets the highest requirements, as it excludes any additives and plastic-containing additives, something that both the planner and the drinking water operator attach particular importance to. This purely mineral mortar is also impermeable to water, chloride-proof and impresses with its very low porosity. MC-RIM PW 111 thus offers a high resistance to hydrolysis. It even performs better than required by the DVGW (Deutscher Verein des Gas- und Wasserfaches e. V.).