It’s a propitious time to be working on water issues. Author Charles Fishman noted, “In the last century, we moved water to people; in the next century, people will move to water.” The Chicago region can have a robust economy going forward because of our access to fresh water and our transit infrastructure. But the Metropolitan Water Reclamation District must reinvent itself as a 21st century resource recovery agency, finding and capturing the value in what we previously considered ‘waste’ — the methane gas generated by the treatment process, the biosolids, nutrients, and wastewater itself.
Happily I can report that this transformation into a resource recovery agency is now underway. One has only to look at the back cover of the MWRD’s 2015 budget book to see the numerous initiatives the District is undertaking.
Nutrient recovery: In 2015 the MWRD will begin using a sustainable biological process to recover phosphorus from the treated water discharged at the Stickney Water Reclamation Plant (considered the world’s largest treatment plant). The recovered phosphorus — harmful in waterways but essential for plants to grow — will be sold in the form of crystals or “ prills” to a commercial fertilizer blender and then sold as a slow–release fertilizer for agricultural use in the Midwest generating revenue for the District.
Biogas generation: The MWRD’s anaerobic digesters produce biogas (methane), which is used to produce steam to heat buildings and treatment plant processes. A new project will divert 440 tons a day of food waste from the city of Chicago’s solid waste stream, feed it into the digesters at the Calumet treatment plant, generate 160 percent more methane gas, and sell some of this gas back into the natural gas pipeline. This will help MWRD on its path to become energy neutral and will divert waste from landfills, reducing greenhouse gas emissions from truck trips and cutting the city’s tipping fees.
Beneficial use of biosolids: The solid wastes generated from sewage treatment are called biosolids and they are an environmentally friendly and nutrient–rich alternative to chemical fertilizer. MWRD is working with the city of Chicago to produce a high–quality compost product using biosolids mixed with wood chips. The District is also working with the Illinois EPA to permit it to develop a residential distribution system providing biosolids as an amendment to topsoil.
Reuse of treated water: Working with the Illinois Department of Natural Resources and large industrial users of water in the Stickney and Calumet service areas, the MWRD is exploring options for the reuse of treated water by water–intensive industries. By offering treated water to industrial users for non–potable use, the District promote good stewardship of precious freshwater resources, industries can achieve significant cost savings, and additional fresh water allocations from Lake Michigan will be conserved or made available to communities in need.
Denitritation: Nitrogen in the form of ammonia can contribute to water quality problems and requires a lot of energy to remove from wastewater using existing technology. In 2015, the MWRD will begin removing excess nitrogen from wastewater at the Egan plant in Schaumburg using an innovative and efficient process called denitritation that will save as much energy as is consumed by 4,500 homes a year.