10-12-2016 Council Packet - Laserfiche WebLink

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STAFF REPORT TO: Mayor Keis and Members of City Council FROM: Bill Dircks, Public Works Director DATE: October 7, 2016 RE: Sanitary Sewer Manhole Grouting The City received $25,000 in grant money from the Metropolitan Council for the purpose of eliminating inflow and infiltration from the City’s sanitary sewer system. Different projects are eligible for different paybacks from the grant money. To date, funds have been used on manhole seals on the 2015 and 2016 construction projects. It is estimated that there will still be approximately $11,000 of grant money remaining following the seal work. Another eligible project is manhole grouting. Manhole grouting is 100% eligible and is reimbursed at 50% of the project costs. There are at least 20 manholes in the system that are leaking at different areas in the manhole. Leaks allow groundwater to enter the sanitary system and the City has to pay to treat the clean groundwater. Typically the leaks occur at the base, at a joint between precast sections, or at a lifting hole or ladder penetration. Grouting the joints is a way to stop the leak and is a cheaper alternative than spraying the entire manhole structure with a form liner. The City has had manholes grouted in the past and staff has found that the method used didn’t hold for very long. The manholes that were grouted in 2009 by Visu-Sewer are all on the list to be grouted again this year. Because of that fact, Thul Specialty Contracting was asked to quote the project. Thul uses a quick set cement to slow the movement of water so they can properly inject a polyurethane grout into the joint. Other companies simply inject the grout and that may be why the grouting doesn’t hold up. It isn’t given time to properly set before the water attacks it. A quote was also received from Hydro-Klean (formerly Infratech) so that Thul’s prices could be compared to the standard style of grouting. The quotes were submitted in different form from each company but the numbers end up being pretty close. Hydro-Klean is probably a bit cheaper, but staff feels it is warranted to use Thul Specialty Contracting to see if their process holds for a longer period of time. Both quotes are included with this memo for your information. Staff does not have an exact number of joints, bases, and defects that need to be sealed since it is difficult to tell until one is down in the manhole but there are at least 20 manholes that need work and many of those will require more than one type of fix. The City needs to spend about $22,277 on the project to receive the remaining $11,138 of grant money. Staff believes there is enough work to get to that amount. Staff recommends awarding the manhole grouting project to Thul Specialty Contracting for work to amount to approximately $22,000 so that the City can receive all of the grant money for which it is eligible.