Design Aspects, Energy Consumption Evaluation, and Offset for Drinking Water Treatment Operation

Abstract

Drinking water treatment, wastewater treatment, and water distribution are energy-intensive processes. The goal of this study was to design the unit processes of an existing drinking water treatment plant (DWTP), evaluate the associated energy consumption, and then offset it using solar photovoltaics (PVs) to reduce carbon emissions. The selected DWTP, situated in the southwestern United States, utilizes coagulation, flocculation, sedimentation, filtration, and chlorination to treat 3.94 m3 of local river water per second. Based on the energy consumption determined for each unit process (validated using the plant’s data) and the plant’s available landholding, the DWTP was sized for solar PV (as a modeling study) using the system advisor model. Total operational energy consumption was estimated to be 56.3 MWh day−1 for the DWTP including water distribution pumps, whereas energy consumption for the DWTP excluding water distribution pumps was 2661 kWh day−1. The results showed that the largest consumers of energy—after the water distribution pumps (158.1 Wh m−3)—were the processes of coagulation (1.95 Wh m−3) and flocculation (1.93 Wh m−3). A 500 kW PV system was found to be sufficient to offset the energy consumption of the water treatment only operations, for a net present value of $0.24 million. The net reduction in carbon emissions due to the PV-based design was found to be 450 and 240 metric tons CO2-eq year−1 with and without battery storage, respectively. This methodology can be applied to other existing DWTPs for design and assessment of energy consumption and use of renewables.

Direct biohydrogen production from chitosan harvested microalgae biomass and an isolated yeast

“…The energy consumption obtained for all the flocculants coagulants is comparable to the obtained in other studies , which is taking account the current density of microalgae culture [10,44].…”

Renewable Energy Generation and GHG Emission Reduction Potential of a Satellite Water Reuse Plant by Using Solar Photovoltaics and Anaerobic Digestion

“…A sensitivity analysis was performed on solar panel efficiency. If a low panel efficiency value of 15% was used [26,30,31], this would result in a reduction of 25.0% of the energy generated by the panels. If a high panel efficiency of 23% was used [62], an increase in energy generation of 15.0% would result.…”

“…To decrease the GHG emissions and dependency on fossil fuels, the use of renewables as energy source in wastewater treatment has become popular. Efforts to offset the energy consumption of the WWTPs include methane generation from anaerobic sludge digestion and the installation of PV solar panels [23][24][25][26][27].…”

Lifecycle Assessment of Two Urban Water Treatment Plants of Pakistan

“…Modified after [37]. Table S1: Environmental emission pathways relevant to the LCA of the water treatment studies; Table S2: Data types and sources indicating the quality and authenticity of inventory dataset; Table S3: Characteristic parameters for raw and treated water and sludge for the study systems; Table S4: Electricity consumption in kWh per m 3 for unit processes at the study water treatment plants; Table S5: Transport distances for chemicals and materials used at the study plants; Table S6: Environmental impact categories and measurement Author Contributions: Conceptualization, S.J., S.P. and S.U.U.J.…”

“…This is primarily due to the heavy reliance of water utilities on the energy sector in addition to their extensive chemical usage [2]. In the U.S. alone, an estimated 45 million tons of greenhouse gases (GHGs) are emitted annually from the energy used for water and wastewater treatment [3]. The need to evaluate the environmental impact of water treatment systems is driven by multiple challenges, particularly the regulatory criteria, present infrastructure condition, population growth, and financial constraints [4,5].…”