By Rosemary K. Otzman
A required report submitted to the state on Sept. 17 by the Ypsilanti Community Utilities Authority reports that a YCUA Service Supervisor noticed raw sewage flowing out of a manhole on Snow Road the day before.
The report said 360 gallons of raw sewage had bubbled up from a manhole on Sept. 16 next to Rawsonville Elementary School in Washtenaw County.
Luther Blackburn, YCUA Director of Wastewater Operations / Compliance, submitted the six-page, required report to the state and Van Buren Township Supervisor Linda Combs, among others.
When it started is unknown, but the sanitary sewer overflow was discovered at 11:03 a.m. and the overflow ceased at 12:06 p.m. The amount is estimated by multiplying 3 gallons per minute times 120 minutes = 360 gallons of raw sewage.
The reason for the discharge was determined to be an air relief valve (ARV) on the force main from the YCUA Snow Road Pump Station stuck open from grease and debris allowing wastewater to fill the valve pit and spill onto the ground.
The valve pit is located across from 3145 Snow Road, Ypsilanti Township.
The Huron River was impacted by the discharge. YCUA said in the report that it believes wastewater impacted three storm water catch basins, two in front of the elementary school and one at the intersection of Grove and Snow roads. Based upon a visual inspection of the catch basins, YCUA believes no wastewater left the sumps of these catch basins.
Land impacted by the discharge was the ground and concrete curb between the valve pit and the storm drains.
YCUA vacuumed wastewater leaking from the ARV pit until the isolation valve was uncovered and closed. They vacuumed and cleaned all curbing, ground, and impacted storm water catch basins.
YCUA has a preventative maintenance program of flushing ARVs on force mains at least once per year. Now it is evaluating the frequency of preventative maintenance on this system and procedures for cleaning wet wells of upstream pump stations.
YCUA reports it notified Rawsonville Elementary School Principal Delria Crippen at 11 a.m. on the day of the incident, MDEQ at 2 p.m., Washtenaw County Emergency Management director at 2:10 p.m., the local health department at 2:45 p.m., left a message at an unspecified daily local newspaper at 3 p.m., and called Brenda Kurtz at Van Buren Township at 3:15 p.m.
The report included the YCUA laboratory report for the overflow grab sampling for E. coli analyses that stated water at Snow Road samples #1 and #3 showed a reading of 2,419,600 MPN/100 ml. (Most Probable Number). Sample #2 showed 218,700. Sample for Huron River #1 was upstream at 66.4. River sample #2 at Rawsonville Road was 218,700, Huron River #3 at the DNR Boat Launch was 128.4, and #4 and #5 downstream in the Huron River showed 24.1 in the cove on the west side of the point at Van Buren Park and 13.2 at the Van Buren Park beach.
By Rosemary K. Otzman