Do You Wonder About the Future of Wastewater Treatment?
Are you a techie, wanting to keep up with the latest trends in wastewater treatment technology? If so, you would be very excited to hear what was presented at the WEF/IWA Nutrient Removal and Recovery (NRR) Conference held this year in Denver. First off, let me explain this conference. It is a joint conference between the Water Environment Federation (WEF), the US organization that puts together WEFTEC and the International Water Association, a similar organization on a global level. NRR is a specialty conference which is small but very focused. It is like WEFTEC on steroids, at least as far as nutrients go. Many of the stars and rising stars in the water business participate.
There was also a small tradeshow. YSI had a booth along with a dozen other or so equipment and technology vendors. Some existing and prospective customers dropped in to learn more about the IQ SensorNet and other YSI products.
When I wasn’t at the booth, I was attending many of the great Technical Sessions. Session topics included shortcut nitrogen removal, biological phosphorus (P) removal, carbon management, and aerobic granular processes to name a few. Many of the presentations were based on technologies that are in the demonstration phase or are being used to optimize full-scale systems. The drivers for facilities to adopt technology to solve their water problems are many but treatment requirements for nutrient removal are definitely at the forefront. However, sustainability and doing more with less are very significant, also.
Let me offer one example from a speaker at the Opening General Session. A municipal WWTP in Virginia was on its way to an expansion to double treatment capacity doing away with some inefficient practices for nutrient removal with chemicals in the process. The Great Recession and other developments caused the utility to change course and scrap the $275 million project leaving the facility to continue expensive chemical addition practices. The proposed solution is treatment intensification which involves rearranging the process flow sheet to achieve a higher level of treatment with new technology. The pricetag is still $20 million but chemical usage would be substantially reduced.
I attended many more presentations including a number of which demonstrating how process monitoring of critical parameters is important for successful implementation of many of the technologies.
- Dissolved oxygen - Control of dissolved oxygen (DO) at very low concentrations was common to many technologies. Besides the obvious energy impacts for conventional nitrogen removal, it also facilitates shortcut nitrogen removal, or removal of nitrogen through nitrite with the additional benefit of substantially reduced carbon requirements.
- Oxidation reduction potential (ORP) - ORP will continue changing even when DO and nitrate are near zero. Control of the anaerobic zone to achieve an ORP of -300 mV or less is critical for P release and optimizing enhanced biological phosphorus removal (EBPR). Continuous monitoring of ORP helps facilities to know when one or more factors is limiting P release and allows them to optimize by adjusting operating parameters until the desired conditions are achieved, e.g. mixing intensity or return activated sludge (RAS) flow into the anaerobic zone.
- Ammonium – Ammonia based aeration control (ABAC) is now embraced, if not yet widely implemented, in wastewater treatment. However, there is still some debate as to the most desirable operating strategy. One presenter recommended maintaining ammonia at not less than 1 mg N/L for the purpose of nitrite oxidizing bacteria (NOB) outselection and shortcut nitrogen removal. The following presenter said that was all wrong and that aeration should be maintained until just before ammonia goes to zero. The debate was not resolved that day. In either case, a reliable ammonium probe will be a requirement to implement the strategy.
- Carbon parameters (COD and BOD) – The availability of degradable carbon is very critical for both N removal and P removal. Continuous monitoring of soluble COD is useful to know when carbon is limiting and to minimize dosing from external chemical sources.
The 2017 WEF Nutrient Removal Symposium will be held in Ft. Lauderdale from June 10 to 15. The symposium is a little different than the Conference but the content is very similar except for maybe greater participation from practitioners. I strongly encourage you to attend. It may take some time to convince your boss to approve your attendance, so you better start working on him or her early. YSI will be there to stay on top of trends in technology. We hope to see you there. In the meantime, we will be sharing the observations above and additional insights from the conference in upcoming trainings and presentations to help keep you informed. Please watch for announcements in e-mail or at ysi.com.
Additional Blog Posts of Interest:
Dr. Smith's Travels in the World of Wastewater
Wastewater Monitoring & Control Instrumentation | How Does It Work?
Online Monitoring of Ammonium and Nitrate Helps Facility Meet Strict Discharge Limits
Enhanced WWTP Performance & Reduced Operating Costs | Online Monitoring and Control