How water resource recovery facilities support climate adaptation strategies.
The Wastewater-Energy Nexus
The water sector offers immense opportunities to transition to a more energy-efficient and decarbonized tomorrow.
I’ve spent my career working to advance the paradigm shift toward a low-carbon, low-energy and climate-resilient water sector. With the world placing an increased emphasis on climate change adaptation, the multi-dimensional aspects of and uses for wastewater are garnering attention as municipal utilities seek to become more sustainable.
The wastewater sector offers immense opportunities to transition to a more energy-efficient and decarbonized tomorrow. The water-energy nexus approach has been successfully implemented at various scales to drive energy and carbon neutrality through innovative technologies and operating strategies. At the head of the pack, Water UK announced its net zero emission commitment by 2030 — the world’s first sector-wide commitment of its kind.
I’m passionate about this topic — my first project with Jacobs was working with Toronto Water to develop a long-term energy optimization plan and greenhouse gas reduction goals for Canada’s largest water and wastewater system. This has been a springboard for me to help clients more fully explore how water resource recovery facilities (WRRFs) can help combat our climate emergency.
Current and new technologies on the horizon
Here’s just four of the many promising areas that I’m seeing clients embrace.
- Energy recovery from biogas will become the baseline for all facilities that have anaerobic digesters (where microorganisms break down organic material). Biogas energy recovery technologies are well-established, such as cogeneration to recover electricity and heat, or purification to renewable natural gas (also referred to as biomethane) for grid injection or used as vehicle fuel.
- Improving anaerobic digestion performance to boost biogas production is key to achieving net zero emissions at WRRFs. There are several available technologies, such as thermal hydrolysis (a chemical reaction where water breaks down a bond) pre-treatment, thermo-chemical pre-treatment and biological hydrolysis.
- Beneficial reuse of biosolids will be the primary biosolids management strategy for the circular economy, such as agricultural land application of biosolids or biosolids product, and use of biosolids product in other sectors (such as road construction and environmental remediation sites). And interest is growing in converting sludge or biosolids to low-carbon intensity bio-fuel through thermal conversion processes.
- Energy recovery from wastewater provides a low-carbon, low-cost and reliable alternative for building heating and cooling. In certain locations, sewer thermal recovery could also help reduce thermal pollution in waterways. This is a scalable solution that can be implemented from individual building level to large scale district energy systems.
Recovering Energy from Biogas
The recently commissioned cogeneration facility at the San José-Santa Clara Regional Wastewater Facility, the largest advanced wastewater treatment facility in the U.S., won a 2021 Design-Build Institute of America award.
As the world transitions to renewable energy generation, we need to leverage synergies between both sides of the nexus.
For example, renewable microgrids with energy storage can be implemented at WRRFs to improve power resilience and redundancy (instead of traditional diesel or a natural gas standby power system), and reduce energy use, cost and associated GHG emissions.
We’re also seeing growing interest in low-emission hydrogen production, which offers opportunities to explore WRRF-based hydrogen hubs, if the site has unused land and potential off-takers for the hydrogen. Green hydrogen production requires renewable energy and recycled water — many WRRFs provide access to these two resources.
The Hydrogen Economy Offers Opportunities for Utilities
In collaboration with Yarra Valley Water in Australia, Jacobs recently published a white paper on the hydrogen economy and potential application for water utilities.
This is an exciting era in wastewater as we embrace the challenges and opportunities climate change presents, and municipal utilities can play a critical role in advancing toward a net zero future. ■
