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Improving performance and reliability in wastewater treatment: Q&A with Dr. Mark Greene

Mark Greene, PhD

Mark Greene, PhD is a leader in providing technical guidance for wastewater treatment and biosolids handling applications. He is an expert in biological wastewater treatment, particularly in the areas of municipal and industrial wastewater treatment, anaerobic digestion for biosolids and high-strength industrial wastewater, and environmental process research and development. He has conducted process modeling and many treatability studies, and frequently publishes and presents in the field. 

We sat down with Mark, a thought leader at OBG, to learn more about his perspective on the industry, OBG's water business, and how technology is improving performance and reliability of wastewater treatment facilities. 

Q: You’ve worked in the wastewater treatment industry for more than 35 years, including nearly 20 years at OBG. How is OBG using advanced technology to compete in the industry?

A: In wastewater treatment, we differentiate ourselves by offering innovative solutions that improve performance and reliability, while using and optimizing existing equipment as much as possible. We are always looking for ways to reduce energy consumption in treating wastewater to meet higher standards and recovering energy from the treatment residuals. Automation of process control and process intensification are common methods to optimize the performance of existing equipment and systems.

Q: How is the water business at OBG making an impact on the world?

A: We make an impact by modernizing old plants and providing extra levels of treatment to comply with new, more restrictive permit limits. The new limits result from increased environmental concerns that may come about due to improved analytical methods/instruments and the ability to measure substances in the part per billion or part per trillion levels. Historically, the part per million levels were adequate to show environmental safety.

Q: Can you talk about some of the interesting projects you’re working on?

A: Many water resource recovery facilities (previously known as wastewater treatment plants) have significantly improved public health by treating sewerage and cleaning water to safe standards. Recently, we have worked on several projects to improve disinfection of treated effluent. Chlorine is the most common disinfectant, but residual amounts can be harmful to the environment. Our disinfection projects have installed alternative technologies like ultraviolet light disinfection, and evaluated the use of different chemicals like peracetic acid.

Another set of projects has focused on using state-of-the-art aeration technologies to improve secondary treatment and remove nutrients (nitrogen and phosphorus) in addition to the normal organics and suspended matter that has historically been done. Many times, the new technologies can accomplish the higher degree of treatment in the same plant footprint as the older systems that they are replacing.

Thirdly, some of our projects have looked at more efficient ways to divert organics from the influent wastewater stream directly to energy recovery. Historically, these organics have been removed by adding energy to grow bacteria, which consume the organics in the process. This diversion happens during primary treatment and results in reduced energy consumption for secondary treatment.

Q: How are you contributing to OBG as a thought leader in wastewater treatment?

A: OBG is committed to improving the environment and protecting the health of our communities with better wastewater treatment that uses less energy. In my work, I help with the conceptual engineering to use and implement innovative process technologies. This includes directing evaluations and studies to determine the effectiveness of process changes or installation of new equipment and systems, often using computer models, as well as delivering presentations and papers to share the results of using new, optimized, innovative solutions for cleaning wastewater to higher environmental standards.

About Mark Greene, PhD: Mark is an expert in biological wastewater treatment, particularly in the areas of municipal and industrial wastewater treatment, anaerobic digestion for biosolids and high-strength industrial wastewater, and environmental process research and development. He received a doctorate in chemical engineering from Cornell University and a bachelor’s degree in chemical engineering from Clarkson University. Mark is actively involved in the Water Research Foundation and the New York Water Environment Association (NYWEA). He was recently recognized for his long-time service to NYWEA and inducted into the association's Hall of Fame at its 90th annual meeting.

Learn more about how OBG brings the latest thinking to some of today’s most challenging areas—from advanced water treatment to sediment management and emerging contaminants; resilient energy, water, and coastal infrastructure; and smart manufacturing—in our Insights from OBG Thought Leaders video.