Water resource recovery facilities (WRRFs) are among the most common pieces of municipal infrastructure. It’s accepted practice for communities of all sizes to treat wastewater in some way before returning it to the environment. As the worldwide focus on issues like water quality and waterborne diseases has increased, so has the attention being paid to the effectiveness of our wastewater treatement regimes. WRRFs perform an essential task and the professionals who operate them are under constant pressure to maintain and even improve the quality of the water that re-enters the natural environment.
Increasingly, people are also asking if WRRFs can improve in another way: Can the energy contained in the wastewater being treated be harnessed to lower or even eliminate the amount of energy needed to run the facilities? After all, the water entering these plants is packed with potential. Thermal energy can be extracted from warm water. Energy can be derived from the nutrients in the water through various chemical reactions and the force of the water entering the facility may be sufficient to generate kinetic energy.
A number of years ago, the Water Environment Research Foundation (WERF) commissioned a study that looked at this issue. The results are interesting and point to the possibility that a lot of the WRRFs currently in operation can potentially reduce or even eliminate their energy bills altogether.
The study’s authors found that across a broad range of treatment methodologies, technology exists to make WERFs ‘energy neutral’. However, there are challenges to consider. Every WERF is operationally unique and what one facility needs to become a net-zero energy user is not what another facility may need. The researchers determined that the challenges that operators faced could be placed into one of three broad categories: technical, organizational and financial. The study did conclude that whatever the challenge, strong leadership was need to drive the process (a link to the research paper can be found here).
There have been some noteworthy successes in the move to net-zero energy consumption. For instance the Gresham, Oregon wastewater treatment plant saw its monthly energy bill reduced from $50,000 to zero through a combination of solar array deployment and biogas production. New York City is also learning valuable lessons as it works toward meeting its goal of net zero energy usage at its 14 wastewater treatment plants by 2050. The city’s Port Richmond facility uses the biogas it collects to partially run its operation. The building also generates about 10 percent of its electricity needs from rooftop solar cells.
These are interesting times in the wastewater management sector. It’s both fascinating and encouraging that the technology already exists to move our WRRFs towards energy neutrality. Maybe one day soon the push will be toward ‘energy positive’ facilities. Here at LuminUltra, we’re excited to see what comes next.