Session 15B: Wastewater Process
3:00pm - 3:45pm
Disrupting the Paradigm of Primary Treatment
Lakehaven Water and Sewer Authority, United States of America;
How do you change paradigms? In his book “The Structure of Scientific Revolutions” Thomas Kuhn explains one must keep pointing at the anomalies and failures in the old paradigm. Don’t waste time with reactionaries; rather work with active change agents and with the vast middle ground of people who are open-minded. Wastewater treatment operators, with their unique perspectives on treatment and large numbers in the industry, have the power to drive real improvement in primary treatment and be the change agents.
Misaligned goals led to the current paradigm.
WWTP Owners: Sustainably take in wastewater, remove the solids then return the separated water and solids to nature with a reliable, easy to operate system.
Consulting engineer: Make money by selling billable hours.
Clean Water Act Regulators: Restore and maintain the chemical, physical and biological integrity of the nation's waters.
Equipment manufacturer: Sell the most equipment for the highest price by producing low maintenance, easy to operate equipment that needs replacement every few years.
I want to tell a story, through the example of an attempt at primary treatment disruption, of how misaligned goals of the various market players make disruption difficult. Clear Cove recognized primary treatment has not changed significantly since humans started building wastewater treatment plants and the industry solution to regulation has been adding in layers of treatment from secondary biological treatment to tertiary filtration. How about a solution that removes as much of the solids and carbon at the start of treatment? Clear cove built and tested this type of system starting in 2008 at small, medium and large WWTP’s but today if you go to their website you get “Not Found The requested URL /municipal/harvester-sewage-treatment/ was not found on this server.”
What happened to Clear Cove and what can we learn from their attempt at disruption? I will tell the story of their three pilot projects aimed at radically improving the separation of solids during primary treatment Reducing the treatment load on secondary treatment would make WWTP’s easier to operate and reduce energy use. This future is possible but only with operators' ideas and wisdom.
3:45pm - 4:30pm
Optimizing Polymer Mixing and Activation: Following the Science
UGSI Solutions, United States of America;
Despite the wide-spread use of polymers in water and wastewater treatment and their associated high recurring expense, understanding exactly how to optimize polymer use in water and wastewater treatment is not well understood. With many equipment options available to operators, it makes sense to start with the basics of polymer chemistry and then apply those principles to polymer activation equipment options. This discussion will review the basics of polymer chemistry, goals of activation, the development of polymer mixing equipment and equipment configuration basics.
Factors such as charge site exposure, polymer hydration, application of mixing energy and the effects of dilution water will be detailed as they influence proper polymer activation. Additionally, the impact of water quality attributes such as disinfectant residual levels and hardness on optimal polymer hydration are explored. Given the industry trend of using reclaimed water for polymer mixing, it is crucial to understand the effects of residual chlorine, turbidity, and various dissolved ions.
Finally, the benefits of utilizing two-stage mixing - very high initial mixing energy followed by low and uniform mixing energy - are demonstrated by theoretical consideration and practical test data. Emulsion polymer systems with sufficient residence time have proven to provide a more efficient polymer solution. Lastly, both mechanical and hydraulic polymer activation systems will be analyzed to assess their efficiency and adherence to the principles of polymer activation previously discussed. Included in this discussion are equipment features and the latest improvements that help ensure efficiency and reliability for utilities and treatment plant operators.