Technical Note 4 - Reuse water: grey water treated in constructed wetlands

Greywater is a potential source for producing water that can be reused for non-potable purposes. The use of nature-based solutions (NBS) for greywater treatment can contribute to the mitigation of heat and low relative humidity in urban areas. Thus, the goal of this technical note is to present the performance of constructed wetlands, a NBS, with respect to the main parameters of national and international standards considering water reuse, and to assess the suitability of the treated effluent for different reuse purposes. Design examples and a flowchart are presented to support the decision-making process, addressing aspects from the characterization of greywater until choosing an application for the recovered water. In this way, we expect to provide a starting point for enabling an increased reuse of treated greywater for non-potable purposes in Brazil, assisting designers, as well as technicians from regulatory bodies, in the design and evaluation of treatment systems using a simple and promising ecotechnology.