Assessing Opportunities for Municipal Wastewater Reuse in the Metropolitan Chicago Area

Water use practices in the Chicago metropolitan area are inefficient and they have led to violations of the United States Supreme Court decree that governs water diversions from Lake Michigan. An alternative approach that encourages reuse of municipal wastewater could address many of the inefficiencies. Although wastewater reuse has been practiced in Illinois, it is rare, especially in an urban setting. This report describes barriers and incentives to wastewater reuse in the Chicago metropolitan area and considers how that information could be used to promote changes in water management policies. Major findings of this study include: A conservative estimate of the amount of treated municipal wastewater that could be used in industrial applications ranges from 2.1X10{superscript} 5 to 2.9x10{superscript} 5 m3/d (55 to 77MGD); Risks associated with reusing treated municipal wastewater can be divided intothree groups. Human health risks are primarily associated with residual organicmaterial and pathogens. Ecosystem risks are primarily related to nutrients andresidual organic materials. Infrastructure risks (corrosion, scaling, biofilmformation) could be associated with changes in water quality, higher temperatures,and assimilable organic material; Human health risks associated with reusing treated effluent depend on the application. Relative to irrigation and groundwater recharge, closed-loop industrial processes probably exhibit less risk. Decades of research with groundwater recharge sites suggest that these processes can be designed and managed to minimize risks; Because the cost of municipal water in the City of Chicago is among the lowest in the nation, there is little economic incentive for wastewater reuse. Major economic barriers to wastewater reuse include the cost of installing a secondary water distribution system and the cost of installing and implementing chlorination at wastewater treatment facilities where chlorination does not already exist. Most of the cost for a nonpotable water distribution system is associated with the capital costs of installing a secondary distribution pipeline; The Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) hasyears of experience with wastewater reuse through many different applications andthey could play a lead role in promoting wastewater reuse. Some of the major recommendations from this work are to: Educate stakeholders (industry, government, the public) about water reuse; Develop reliable data on industrial and commercial water use patterns and water quality needs; Encourage federal, state, regional, and local authorities to adopt water reusepolicies.