Designing a large-scale disinfection facility for cleaner effluent discharge focuses on creating a cost-effective integrated system while on an aggressive timetable.

By: Paul Swaim, Vice President, P.E., CH2M HILL

Paul Swaim will present his paper “Big Disinfection in Chicago: The Fast-Track Design of 480-MGD Disinfection Facilities for the Calumet Water Reclamation Plant” on Wednesday, Oct. 9 at 1:30 p.m. in TS609 during the Water Environment Federation Technical Exhibition and Conference (WEFTEC) in Chicago, Illinois. Learn more about CH2M HILL’s WEFTEC 2013 participation and technical sessions.

The Metropolitan Water Reclamation District of Greater Chicago (MWRD) has directed a team, including CH2M HILL, to implement disinfection facilities at its Calumet Water Reclamation Plant (WRP) by 2016. At 480 million gallon per day (MGD) peak flow, the disinfection facilities at Calumet will be among the largest in North America.

In order to implement the best disinfection system, the MWRD assembled a task force to complete a triple bottom line analysis of available disinfection technologies that considered economic, environmental and social criteria. From this evaluation, a chlorination/dechlorination disinfection technique was selected for the Calumet WRP, due to the cost savings associated with the presence of an existing chlorine contact basin. MWRD also selected delivered bulk liquid sodium hypochlorite as the most efficient disinfection approach. This decision was based on the close proximity of the chemical supply which lowered the cost, reduced greenhouse gas production, reduced power use and increased safety.

In agreements between the client and stakeholders, a fast-track schedule was necessitated to meet the timeline of implementing disinfection by 2016. CH2M HILL is working to meet the fast-track schedule, with the design completed in less than one year. The design effort focused on designing an integrated system that will work well within the existing plant footprint, maximize performance, minimize power requirements and meet discharge requirements in a cost-effective manner.

As designed, the disinfection facilities will include six large sodium hypochlorite storage tanks, providing more than 100,000 gallons of chemical storage, as well as three large sodium bisulfite storage tanks providing more than 30,000 gallons of chemical storage. At the start of the disinfection season, filling the chemical storage systems will require more than 30 deliveries via chemical tanker trucks. The design of such a large system has required addressing unique considerations, including the following:

  • Accommodating chemical delivery vehicles was a primary consideration in selecting the optimal location on the WRP site.
  • Site selection also preserves space for future pumping and advanced treatment technologies (e.g., filtration, additional nutrient removal).
  • Selecting the best approach to chemical storage required balancing cost, security and protection of chemical viability.
  • Selecting the right chemical storage volume required balancing building footprint (and cost) with an acceptable inventory for operations.

Construction is now underway to build the innovative “big disinfection” system for the Calumet Water Reclamation Plant that will increase disinfection for cleaner effluent discharge. Construction bids came in below the Engineer’s estimate, and the project will provide a number of benefits to the community, as noted by MWRD at their website:

The information presented at WEFTEC will be applicable to utilities implementing a new disinfectant, utilities implementing a project on an aggressive schedule, utilities considering switching from gaseous chlorine to a new disinfectant and all within the industry interested MWRD’s approach in implementing disinfection at a large scale.

Paul Swaim, a recognized international expert in disinfection for drinking water, water reuse and wastewater applications has more than 20 years of experience in the successful delivery of projects. He recently completed his term as President of the IUVA. A CH2M HILL Vice President, Senior Principal Technologist and the Deputy Global Service Leader for Water Infrastructure in the Water Business Group, Paul received his B.S. and M.S. degrees from the University of California at Berkeley.