Evaluation of harvesting urban water resources for sustainable water management: Case study in Filton Airfield, UK.

Filton Airfield in the UK is a new community under development aiming to become self-sufficient in its water supply toward a circular economy. Urban water management strategies, water demand minimization, urban resource reuse, and wastewater discharge minimization, can improve the urban circular economy. Understanding the practical impacts of those strategies is crucial for a new development area like Filton. As a site investigation, the physiochemical and microbial characteristics of raw rainwater showed acceptable for irrigation and drinking water, indicating no significant risk of using rainwater collected within Filton, but still requiring a treatment process depending on chosen applications. This study further conducted stochastic water demand profiles and urban water cycle simulations at a block scale, taking possible rainwater harvesting (RWH) and greywater recycling (GWR) options for non-potable purposes to quantitatively assess the impact of urban water management strategies on urban harvesting potential indicators (0-100%). When the RWH was implemented, the water demand minimization potential varied from 62% to 71%. Meanwhile, the combined use of RWH and GWR yielded even better results in terms of water demand minimization, peaking at 78% due to the additional supply from GWR. The combination also reduced wastewater production potential from 100% to 54% and consequently improves self-sustainability potential from 0 with no recycling, to 44% with only GWR, and to 100% with the combined use of RWH and GWR. The sensitivity analysis revealed that wastewater discharge is the most sensitive to variations in rainfall patterns (wet and dry conditions) and urban density (water demand patterns), indicating that both need to be balanced for better implementation of urban water harvesting strategies. This study can provide insights into the applicability of urban water resource harvesting and its assessment approaches in existing and new development areas.