Life cycle assessment of pipes and piping process in drinking water distribution networks to reduce environmental impact

Drinking water distribution networks (DWDNs) are one of the most significant components of urban water systems. Although the environmental aspects of DWDNs' construction could be very important, limited studies have considered environmental impact (EI) of DWDN. Using Life Cycle Assessment, this paper evaluates the EI of five types of pipe materials in DWDNs, including polyvinyl chloride (PVC), high-density polyethylene (HDPE), ductile iron (DI), fibrocement, and steel. The results indicate that, in the production phase, DI has more EI in most impact categories. In the global warming category of production phase, the EI of one meter of 200 mm DI is 128 kg CO2 eq, six times greater than PVC. With respect to the installation phase, a specific trench was considered for each pipe type to compare the EI of different trenches. In this phase, due to the EI of bedding materials, fibrocement trench has the highest impact. To illustrate the applicability of the proposed method, a part of the Tehran DWDN was selected as a case study, with results demonstrating that a reduction of between 12 and 26% is achievable in the EI of the DWDN from its pipes and piping process by substituting for some of the pipes with environmentally friendly materials.