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HomeMy WebLinkAboutCSD-07-091 - PS21 Old Mill Pumping Station Spill ) R Community Services Report To: Date of Meeting: Submitted By: Prepared By: Community Services Committee October 15, 2007 Greg Hummel, Acting Director of Operations Dan Locke, Manager of Operational Support and Bryan Dubrick, Operations Supervisor Ward(s) Involved: Date of Report: Report No.: Subject: Fairway-Gateway Oct 1 , 2007 CSD-07-091 PS21 OLD MILL PUMPING STATION SPILL RECOMMENDATION: For information and discussion. BACKGROUND: The City of Kitchener has 23 pumping stations located throughout the city. A pumping station functions as a collection/transfer location in which the wastewater is collected and pumped to a higher elevation via a forcemain and then into the gravity sewer system. Kitchener's pumping stations were subject to an assessment by CRA Consultants in 2003 which recommended improvements to their infrastructure. During the 2004 capital budget process $1 ,950,000 was approved to improve the pumping station facilities on a short, medium and long term priority basis. One of the recommendations was to have stand-by power generators installed at the PS21 Old Mill Pumping Station and the Stoke Drive Station. This work was completed in 2007. This leaves one additional station, Springdale Dr. Although it was not identified for immediate installation of stand-by power, the options for stand-by power or station removal will need to be investigated and re-prioritized within the Sanitary Utility capital forecast. REPORT: Station Characteristics The PS21 Old Mill Pumping Station located at 1810 Old Mill Rd contains the following characteristics. Report No: CSD-07-091 2 Station Characteristics provided by CRA Field Verification Report Wastewater Pumping Facilities, March 2005. Ref. No. 31368 (1): · Steel pre-fabricated pumping station, built in 1969 with a separate wet well. Dry pit is accessible through a shaft access via tube ladder · Pumps are two dry pit submersible Flygt Type; field tests indicate capacity at 12 L/s and 13 L/s respectively. · Station inlet via two sanitary sewage pipes · Station discharge is a 300mm forcemain · Station overflow, 300mm pipe from wet well · Standby power is not installed (scheduled for 2007) · Communication, a single telephone service for alarm purposes via a DCS autodialler · Certificate of Approval 3-0204-69-006 (sewage) Note: Since the CRA report PS21 Old Mill Pumping Station upgrades are as follows: · Standby power completed spring of 2007, Certificate of Approval 8287-6PQKU5 (air) · Control building completed spring of 2007 · Pump controls were moved from the steel pre-fabricated underground dry well to the new Control Building completed summer of 2007 · Flygt pump control panel installation in control building completed summer of 2007 The above upgrades that have been completed to date at PS21 Old Mill Pumping Station total approximately $430,000. Note: Outstanding Upgrades to PS21 Old Mill Pumping Station are as follows: · SCADA system with front end alarm handler (scheduled to be completed by late October 2007 in test mode, fully operational by the spring of 2008) · Integration of SCADA system with new Central Alarm System (scheduled to be completed by the summer of 2008) The Old Mill Pumping Station (1810 Old Mill Rd.) alarm and generator testing was performed on September 11 , 2007 by City of Kitchener Operations Staff; the testing process started at approximately 12 noon and was completed by approximately 1 :30 p.m. At 2:27p.m. September 11 , 2007 a high water primary alarm was received by City of Kitchener dispatch (Elmsdale). The alarm was recorded by Dispatch staff as "Testing" and no further action was taken. No further alarms were received by Dispatch until the station was restored by Operation's staff on Friday September 14, 2007 when they attended the site for regular weekly inspections. Phone records indicate that Operations Staff failed to communicate the completion of station testing. On September 14, 2007 at 1 0:13am City of Kitchener staff arrived at PS21 Old Mill Pumping Station to perform regular weekly inspections. Staff found that the station had failed and was spilling sewage into the Grand River. Staff returned the station to a functioning capacity. Staff notified their supervisor who in turn notified his Manager and reallocated staff to the site. Notification to the Spill Action Centre (SAC), the Ministry of the Environment (MOE), the Region of Waterloo Environmental Enforcement, the Region of Waterloo Public Health, and Grand River Conservation Authority (GRCA) was completed by approximately 11 :30 am on Friday, September 14, 2007. Report No: CSD-07-091 3 City of Kitchener staff worked with the area residents to proactively inform them of the spill and address any concerns that they had. One concern as to the safety of the drinking water wells in the area was addressed by the Region of Waterloo Public Health Officer. The City of Kitchener provided bottled water to two neighbouring residents until such time as their wells could be tested. All solids that were released during the spill were captured by the silt fence which was previously installed to retain silt during construction of the control building. This filtered all solid materials out of the effluent prior to it reaching the Grand River. The City of Kitchener proceeded to clean up the affected flood plain area between the overflow discharge point and the Grand River. There are two depressions in this area in which the sewage effluent collected. The effluent from these two areas was pumped back in to the Station wet well. An electrical contractor on retainer with the City of Kitchener was called to the site to trouble shoot. The electrical contractor found a failed circuit breaker which powered the pump control circuit. This failed breaker has been sent back to the manufacture to determine if it was defective. Due to the fact that the station never lost the main power source, only an individual circuit, the standby generator would not be required to operate. Spill Quantitv The quantity of spill that was released via the overflow piping from the station was calculated by determining average daily pump run time from historical data which was 4 hours per day. Based on the CRA Field Verification Report, Wastewater Pumping Facilities, March 2005. Ref. No. 31368 (1), the two dry pit submersible Flygt pumps field tested at 12 Lis and 13 Lis respectively. Therefore average daily pump flow rates would be 12.5 Lis which equates to 7.5m3/hr. From the alarm data we have determined that the station was in failure for approximately 67.5 hours with the additional capacity in the station of approximately 2 hours after the high water alarm. Therefore the duration of the sewage spilled from the station was 65.5 hours. From this we have determined the hourly flow rate of 7.5 m3/hr times the duration of 65.5 hr results in a quantity of sewage released of 491 cubic meters. The configuration of the pumping station property contributed to a portion of the spill being contained on the property in two depressions adjacent to the Grand River. The river is approximately 40 meters east of the overflow outlet. The spillage that was contained in the depressions was pumped back into the station during the site cleanup operation. Measuring the volume of the two depressions, containing 15 cubic meters and 35 cubic meters respectively, this 50 cubic meters pump back was deducted from the station spill resulting in a spill to the Grand River of approximately 441 cubic meters. Site Impact Once the pump back operation was complete staff manually collected any solids that were contained by the silt fence. The quantity of solids that were released in the spill were minimized as the station inlet chamber contains a bar screen designed to filter the solids. This screen is cleaned on a regular basis. The solids that were released were contained by a silt fence which was installed on site for the station upgrade construction. The City of Kitchener installed snow fence in the affected flood plain area where the sewage effluent had flowed over to get to the Grand River. The City of Kitchener also had signs installed on the snow fence to notify anyone who might wander down to the river. Note: this is private property and should not have any pedestrian traffic. The purpose of the fence is also to keep Report No: CSD-07-091 4 animals from entering the area. The fence will remain until such time as the area has had enough precipitation allowing ground filtration to remove any remaining residue. The Region of Waterloo Environmental Enforcement Department was contacted to inspect the clean up and comment on any further action required prior to the City of Kitchener staff contacting Spills Action Centre (SAC) to inform them that the spill clean up had been completed. No further action was required by the Region of Waterloo Environmental Enforcement Officer and SAC was contacted at 7:30pm on September 14, 2007. City of Kitchener staff and the MOE Officer re-inspected the flood plain area the following morning to ensure no further effluent had collected in the two depressions and the MOE Officer stated that no further clean up was required. Next steps 1. Station alarms will include simultaneous calls to the central dispatch center and to a pager carried by on-call staff. This technology which includes a dedicated SCADA system for pumping stations will be installed and utilized at all pumping stations by early 2008 at a cost of approximately $225,000. 2. Interim alarm monitoring will be done by City of Kitchener Dispatch staff until such time as the SCADA system is up and running; all alarms will be called out regardless of Station testi ng. 3. Mandatory contact and logging of all pumping station alarms will be done by dispatch staff and Operations Staff. Both the station log book and the dispatch alarm log book will reference every alarm, the Operatorl Dispatcher that responds, the time, and the action taken. 4. Dedicated dispatch staff to monitor alarms during alarm testing days is required until the SCADA system is up and running. FINANCIAL IMPLICATIONS: Once the station was brought back on line and the site cleanup was complete staff met to determine what measures could be taken to ensure a repeat of this spill is minimized. Should the next steps referenced within the report result in some additional expenditure these additional costs will be absorbed by the operating divisions. Any additional costs identified have been previously approved and are included in the 1 0 year capital forecast for the Sanitary Utility. COMMUNICATIONS: Communications were provided to the media at the time of the spill and an additional media release has accompanied the release of this report. The City of Kitchener notified and worked with the Ministry of the Environment (MOE), Spills Action Centre (SAC), Region of Waterloo Environmental Enforcement, Region of Waterloo Public Health, Grand River Conservation Authority (GRCA) to ensure that all proper procedures were followed. The City of Kitchener Operations Staff hand delivered an information letter to residents in the immediate area to inform them of the incident and to provide them with a contact should they have any concerns. A formal report of the incident was also forwarded to the Ministry of the Environment for their review. Report No: CSD-07-091 5 CONCLUSION: This incident has re-enforced the need to place a high value on communication and systems between all levels of our organization. The City of Kitchener has had one other spill to the Grand River, which was from this same pumping station in February of 2006. Kitchener is proactively improving the pumping stations within the City of Kitchener's sanitary sewer network. The City of Kitchener has improved this station to ensure power supply and will be continuing to improve this station to ensure improved communications. The City of Kitchener is committed to improving all stations by installing the measures outlined within the CRA report. Greg Hummel Acting Director of Operations AP