Net Zero Energy Model for Wastewater Treatment Plants

Abstract

The primary objective of this study is to achieve net-zero-energy (NZE) wastewater treatment plants (WWTPs) by utilizing energy efficiency opportunities (EEO's), combined heat and power (CHP) systems, and other renewable energy sources, e.g., solar, water, and wind powers. This study discusses an innovative energy solution for WWTPs in the United States, and one of the WWTPs with a flow capacity of 1.5 million gallons per day (MGD) was selected as a case study. An optimization tool, Hybrid Optimization of Multiple Energy Resources (HOMER) software, is used in this study to find the best energy system configuration to run the system. An energy audit for one WWTP in early 2020 and the report is used to do this study. The proposed EEO's were able to reduce WWTP energy consumption by about 11%. The excess anaerobic digester gas was utilized in a CHP system to cover about 42% of the facility's consumption. Also, 3% of the utility energy consumption can be claimed by microturbines in the aeration tanks. Another two renewable energy systems, solar photovoltaic (PV) with 29% and water turbines with 15%, contribute to covering 100% of the WWTP energy consumption and achieving an NZE WWTP.

State of the art of windthermal turbines: A systematic scoping review of direct wind-to-heat conversion technologies

“…Hence, the research and development of wind turbines benefit windthermal energy systems. Examples of ongoing research activities for wind power are: wind farm layout design [94,95], turbine power output optimization [94,96], resource mapping [97], and utilizing wind turbines to reach net zero energy facilities [98].…”

Can a Wastewater Treatment Plant Power Itself? Results from a Novel Biokinetic-Thermodynamic Analysis

“…Again, all parameters in Equation ( 2) are defined in Table 1. VSS production from the secondary clarifier is more complex than in the primary clarifier, see Equations ( 3)- (6).…”

“…Nevertheless, energy efficiency of WWTPs has been an important subject because of their high energy consumption. According to the US Environmental Protection Agency, 3-4% of total electricity use in the US is consumed by drinking water and wastewater systems [5,6]. A relationship between energy and water, the "water-energy nexus", has been the focus of attention worldwide due to climate change, population increase and urbanization [7,8].…”

Hydropower Potential for Energy Recovery in Wastewater Systems. Assessment Methodology and Practical Application

“…So their goals were set expecting to achieve 50% self-sufficiency by 2030 (Chae & Kang, 2013;. At lower geographical levels there are many other initiatives promoting the progressive installation of RES (renewable energy systems) (Qandil et al, 2021), such as those in Portugal (Waterworld, 2020) or Spain (Canal de Isabel II, 2020) aiming for a corporative energy neutrality by 2030, with 100% renewable energy production at their own facilities. Nowadays, this neutrality is feasible but still a challenge, as in general, there is not a standalone technology that can help a WWTP to become fully energy-self-sufficient (Chae & Kang, 2013;Maktabifard et al, 2018).…”

“…A few years later, in 2011, it also developed specific goals for WWTPs, as in 2007, this sector represented a 3.5% contribution to those emissions (Chae & Kang, 2013). At lower geographical levels, many other initiatives promoting the progressive installation of renewable energies at water systems can be found (Qandil et al, 2021).…”