Dynamic Influent Load Diversion as a Demand Response Service In Systems of Hydraulically Connected WRRFs.

In recent years, the global discourse concerning sustainable wastewater treatment has shifted toward the decentralization of water resource recovery facilities (WRRFs). In fact, decentralized wastewater treatment infrastructures have been implemented under various settings such as rural, peri-urban, suburban and even urban areas (Siegrist, 2017). Decentralized WRRFs that are hydraulically connected to a centralized sewer collection system are known as satellite WRRFs (Gikas and Tchobanoglous, 2009). A system where decentralized satellite facilities have been integrated within an existing centralized wastewater infrastructure is also known as a hybrid system. In parallel, the progressive introduction of renewable solar energy has resulted in the manifestation of the well-know “duck curve” phenomenon, characterized by an apparent decrease of net power demand of the electrical grid during the late afternoon hours. The challenge associated with balancing supply and demand during grid ramping hours (“neck” of the duck) has motivated energy providers to shift the user’s energy consumption, often by means of economic incentives such peak time-based rates or demand response programs (Musabandesu and Loge, 2020). To address this emerging challenge, this study proposes a new demand response strategy to lower the power required for wastewater treatment during grid ramping hours by taking advantage of the interconnected nature of a hybrid system of wastewater treatment plants. The underlying concept of such strategy relies on exploiting the hydraulic delay of sewer trunk lines for the deferral of the treatment intensity between hydraulically connected facilities during peak energy cost hours.