Pipe materials must be evaluated for their suitability for use in a distribution network of process waters of varying composition. The use of unsuitable materials may result in the formation of deposits, increased particle loading and corrosion damage.

In MULTI-ReUse, three ReUse waters were produced on the basis of modular process chains to make municipal wastewater usable for reuse as process water.

A user-specific distribution network made of suitable pipe materials is required for transport. The corrosion-chemical properties of the produced water and the corrosion behavior of commonly used materials must be coordinated (risk assessment), also taking into account the user-specific conditions.

The results are summarized in the decision tree shown here. From a corrosion-chemical point of view, the use of polymer materials is possible for the three ReUse waters. Depending on the design of the pipe network, the coating formation of manganese has to be considered for ReUse water 1. Metal or cementitious materials require additional stabilizing measures (pH, buffering). For ReUse waters 1 and 2, metallic materials can only be used for a new distribution network under certain general conditions, which relate in particular to the network structure and operating conditions, due to the high neutral salt contents (chloride, sulfate, nitrate). If existing drinking water networks made of metallic materials are to be used for ReUse water 1 or 2, an individual condition assessment (internal corrosion, e.g. incrustations) is necessary in advance, including the possible adaptation of operating conditions. This also applies to the service water networks of the end users, which may require further, decentralized treatment or conditioning of the supplied waters.