Report - Metropolitan Water Reclamation District of Greater Chicago

Section collected the pertinent data during the tests and will prepare a report for M&O in early
2011.
Excess Flow Discharge Disinfection Study for the John E. Egan Water Reclamation
Plant. At the request of M&O, the WTPR Section planned a laboratory bench-scale study to
investigate the chlorine dose required to disinfect the primary treated excess flow of the Egan
WRP. The study evaluated methods to meet the permit limit consistently and produce an
effective disinfection monitoring strategy. As a supplement to Phase I tests in 2009, Phase II tests
were conducted in the WTPR laboratory with the analytical support of the AMBS and the
Analytical Laboratories Division (ALD) in 2010. The effectiveness of disinfection as a function
of contact time and influent characteristics have been investigated. An M&R report detailing the
results from the two phases of this study will be prepared in 2011.
Polymer Tests at the Stickney and Calumet Water Reclamation Plants. Full-scale tests
were conducted at the Stickney WRP post-centrifuge dewatering complex during
September/October 2010 for the selection and purchase of summer polymer used in the
centrifuge dewatering process of anaerobically digested sludge. In October 2010, bench-scale
polymer testing was carried out at the Lue-Hing Research and Development Complex for the
selection and purchase of polymers used in the gravity concentration tanks to thicken the primary
and waste-activated sludge at the Calumet WRP. A total of six polymers from three
manufacturers were tested and found to be eligible for bidding for summer polymer purchase for
the Stickney WRP, whereas only two polymers from the same manufacturers were tested and
found to be eligible for bidding for thickening operations at the Calumet WRP.
Assistance to the Calumet Water Reclamation Plant in Controlling Foaming in
Anaerobic Digesters. The WTPR Section teamed up with the AMBS and provided assistance to
the Calumet WRP operations throughout the year to mitigate foaming problems in the anaerobic
sludge digesters in 2010. Support included microbiological analyses, foaming potential and
related tests conducted in the WTPR laboratories. The results of microbial analysis and review
of the operational data suggest that low food-to-mass (F/M) is causing the foaming. M&R staff
is working with M&O staff to develop and test strategies in 2011 to improve F /M and minimize
foaming.
Providing Technical Support to the Engineering Department for Planning and
Design Requests. In 2010, the WTPR Section conducted the following evaluations to provide
the required technical support to the Engineering Department.
Grit Sampling at the North Side Water Reclamation Plant. In support of the
computational fluid dynamic modeling of the aerated grit tanks at the North Side WRP being
done by the University of Illinois at Urbana-Champaign, grit samples from the raw influent
wastewater were collected in the fall and winter of2010. A sampling device was designed, built,.
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