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Civil Engineering Podcast with Lane McWilliams: Water Tanks as “Cheap Batteries” & Energy Transition in Water/Wastewater Systems

Key Concepts:

• Water Tanks as Batteries: Utilizing existing water tank infrastructure for grid energy storage through strategic pumping and off-peak energy use.
• Energy Transition: Shift from fossil fuels to renewable energy sources and the role of water/wastewater facilities in grid stabilization.
• Equalization Tanks: Tanks used to level out flow variations in wastewater treatment, improving plant efficiency and grid responsiveness.
• Demand Response: Utilities incentivizing facilities to reduce energy consumption during peak demand.
• Load Shifting: Moving energy consumption to off-peak hours when power is more readily available and cheaper.
• Industrial Symbiosis: Collaborative approach to resource utilization, particularly in water and energy management.
• Process Optimization: Improving the efficiency and effectiveness of treatment processes without compromising compliance.
• Nitrogen Removal (Dentrification): Process of removing nitrogen from wastewater through biological processes, improving effluent quality.

1. Introduction & Background

The episode features Anthony Pasano interviewing Lane McWilliams, a licensed professional engineer with 30+ years of experience in water and wastewater infrastructure, specializing in energy footprint reduction. The discussion centers on the untapped potential of water and wastewater facilities as key players in grid reliability, cost control, and sustainability during the ongoing energy transition. McWilliams’ career began unexpectedly with a summer internship at Parametrics, leading to a long-term focus on optimizing energy use in treatment systems.

2. Water Tanks as “Cheap Batteries” – Practical Applications

McWilliams explains the concept of water tanks functioning as “cheap batteries” by leveraging existing infrastructure. Water systems already possess significant tankage, which can be utilized to absorb excess grid energy. This can be achieved through:

• Strategic Pumping: Pumping water during periods of low energy demand (e.g., nighttime) and storing it for later use.
• Demand Response: Responding to grid signals by adjusting pumping schedules to alleviate strain during peak demand (e.g., late afternoon).
• Flow Equalization: Utilizing equalization tanks before wastewater treatment plants to smooth out flow variations, improving plant performance and allowing for more efficient energy use. Operators universally appreciate equalization tanks for their positive impact on plant operations.
• Flexibility: The ability to adapt to grid needs, and adding additional tankage to enhance responsiveness.

This approach is cost-effective compared to large-scale battery storage projects, and simultaneously improves system operation. McWilliams draws a parallel to stormwater detention basins, highlighting the principle of distributing flow over time to prevent overloading systems.

3. Energy Transition & Water/Wastewater Facilities

The energy transition, characterized by a shift away from fossil fuels towards intermittent renewable sources, presents both challenges and opportunities for water and wastewater facilities. Key aspects discussed include:

• Biogas Utilization: Wastewater plants generate biogas as a byproduct of anaerobic digestion. Traditionally flared, this biogas can now be used for:
  • Combined Heat and Power (CHP): Generating electricity and heat on-site.
  • Renewable Natural Gas (RNG): Cleaning and upgrading biogas to pipeline-quality methane for injection into the natural gas grid. Economic viability of RNG is currently influenced by government incentives.
• Distributed Renewables: Utilizing available land at facilities for on-site solar farms.
• Demand Response & Load Shedding: Participating in programs where utilities pay facilities to reduce energy consumption during peak demand. Wastewater plants can typically reduce load for up to four hours without significantly impacting treatment processes.
• Curtailment Absorption: Offering to pump water when renewable energy generation exceeds demand, preventing energy waste.

4. Optimizing Energy Footprint – Unit Processes & Considerations

McWilliams emphasizes a cautious approach to process changes aimed at reducing energy consumption, prioritizing compliance and avoiding operational risks. He outlines a tiered approach:

• Low-Risk/No-Risk Improvements: Starting with simple, easily implemented changes that have minimal impact on treatment processes. Examples include:
  • Plant Water System Optimization: Reducing pressure in plant water systems to lower energy consumption.
  • Equipment Evaluation: Identifying and prioritizing the use of more efficient pumps and blowers.
• Process Optimization: Focusing on ensuring processes are operating as intended, addressing workarounds and inefficiencies that have accumulated over time.
• Nitrogen Removal (Dentrification): Adjusting aeration schedules to promote denitrification, removing nitrogen from wastewater and reducing energy consumption. This is particularly relevant in the Mississippi River watershed due to concerns about the Gulf hypoxic zone.

He stresses the importance of understanding the plant’s energy bill and engaging operators in the process, allowing them to experiment with changes under controlled conditions.

5. Leadership & Buy-In

Successfully implementing energy-saving measures requires effective leadership and buy-in from all stakeholders:

• Establishing Trust: Demonstrating a commitment to compliance and avoiding operational risks.
• Understanding the Culture: Recognizing the conservative nature of the engineering profession and the importance of building credibility. Using correct terminology (e.g., "wastewater" as one word) demonstrates familiarity with the field.
• Empowering Operators: Allowing operators to experiment with changes and providing support for their efforts.
• Focusing on Immediate Benefits: Demonstrating the value of energy efficiency improvements in terms of cost savings and improved performance.
• Highlighting the Human Element: Acknowledging that engineering decisions are made by people and that failures are often the result of human error.

6. Career Advice & Key Takeaways

McWilliams advises aspiring civil engineers to:

• Find a Niche: Identify areas within civil engineering that genuinely interest them and develop expertise in those areas.
• Embrace Continuous Learning: Stay up-to-date with the latest technologies and best practices.
• Seek Mentorship: Learn from experienced professionals in the field.
• Don't Be Afraid to Offer Solutions: Proactively propose solutions to problems, even if they are not perfect.

7. Notable Quotes

• “Water tanks are pretty cheap batteries.” – Lane McWilliams, summarizing the potential of existing infrastructure for energy storage.
• “If it’s not fun, why are we doing it?” – A friend’s advice to McWilliams, emphasizing the importance of finding enjoyment in one’s work.
• “You hired me because you’re capable. So, think a bit and you can come up with an answer just as easy as I can.” – Advice from McWilliams’ first manager, fostering confidence and initiative.

8. Conclusion

The episode highlights the significant, yet often overlooked, role that water and wastewater facilities can play in supporting the energy transition and enhancing grid reliability. By leveraging existing infrastructure, optimizing processes, and fostering collaboration between utilities and engineers, substantial cost savings and environmental benefits can be achieved. The discussion underscores the importance of a holistic approach to infrastructure management, recognizing the interconnectedness of energy, water, and wastewater systems.