NOTICE OF MEETING DES MOINES WASTEWATER RECLAMATION AUTHORITY TECHNICAL COMMITTEE

Transcription

1 NOTICE OF MEETING DES MOINES WASTEWATER RECLAMATION AUTHORITY TECHNICAL COMMITTEE Des Moines Wastewater Reclamation Facility 3000 Vandalia Road Des Moines, Iowa April 9, :30 p.m. AGENDA ITEM 1: ITEM 2: ITEM 3: ITEM 4: ITEM 5: ITEM 6: ITEM 7: ITEM 8: Call to Order Roll Call Minutes for the March 12, 2019 meeting - Approval WRF Digester HVAC Improvements Recommendation WRA West Des Moines Outfall Sheeting Repairs Information Industrial Waste Ordinance Information Other Business Adjourn

2 ITEM 3 DES MOINES WASTEWATER RECLAMATION AUTHORITY TECHNICAL COMMITTEE Draft Meeting Minutes Des Moines Wastewater Reclamation Facility 3000 Vandalia Road Des Moines, Iowa March 12, :30 p.m. ITEM 1: Call to Order Gary Patterson, Chair Person, called the March 12, 2019, Technical Committee meeting to order at 1:30 p.m. ITEM 2: Roll Call Technical Committee Members in Attendance Jim Utter, Altoona Roger McFarland, Ankeny Jeff May, Clive Shane Kinsey, Johnston Gary Patterson, Pleasant Hill Bret Vandelune, Polk County David McKay, Urbandale Dalton Jacobus, UWHSD Rudy Koester, Waukee Brian Hemesath, West Des Moines Paul Ebert, WRF Others in Attendance Tim Royer, Waukee Scott Hutchens, Operating Contractor James Beck, Operating Contractor Roxane Vaughan, Operating Contractor Tina Grove, Operating Contractor Nick Carter, Operating Contractor Jason Merk, Operating Contractor ITEM 3: Minutes for the February 12, 2019 meeting - Approval Bret Vandelune made a motion to approve the minutes of the February 12, 2019, Technical Committee meeting. Rudy Koester seconded the motion. The motion carried unanimously.

3 ITEM 3 ITEM 4: Change Order No. 2 for the WRA Eastside Interceptor, Phase 27, Segments 6 & 7 Project in the Amount of $547, Recommendation James Beck reported that a special WRA Board Meeting was held in February to extend the date for working in the river this winter to March 4, 2019, due to a high flow event. Change Order No. 2 includes costs that the contractor incurred to remove its operation from the river and additional compensation is for costs that the contractor incurred due to excessive scouring at the Des Moines River crossing during the high flows. To protect the new sewer WRA modified the design elevation of the 42-inch sewer throughout the easterly portion of the Des Moines River crossing. This required that additional material hauled in and removed which resulted in an additional cost. The Operating Contractor and HR Green, Inc. have been negotiating with the contractor over the past few weeks for the additional work and have reached agreement on the costs noted above which result in a total cost resulting from the December 26, 2018 rain and subsequent high flow event. The Operating Contractor has reviewed the change order pricing information at length and recommends approval of Change Order No. 2 in the amount of $547, Approval of this change order will constitute full and complete compensation to the contractor for all additional costs associated with the Des Moines River and Birdland Marina crossings. Brian Hemesath made a motion to forward the Change Order No. 2 for the WRA Eastside Interceptor, Phase 27, Segments 6 & 7, to the WRA Board for review and recommendation. Jeff May seconded the motion. The motion carried unanimously. ITEM 5: Industrial Waste Ordinance Information Paul Ebert reported that 34 inspections were completed last month and that most of these occurred in Des Moines on Merle Hay, Locust, and Ingersoll. There was one physical constraint and one economic hardship, both were approved. Scott Hutchens informed the Committee that it appears that almost all of the Communities have begun the process to pass the updated FOG Ordinance. Five Communities have approved the Ordinance. Once your Community passes the FOG Ordinance please send a copy of the Final Document and proof of publication for our records. ITEM 6: Other Business Jim Utter asked what the status of the WRA Biogas Conditioning & Injection project was. James Beck provided an update and noted that startup of the system is anticipated for the end of Scott Hutchens reported that Staff has been working on the Strategic plan implementation quarterly update publication and should be available soon.

4 ITEM 3 ITEM 7: Adjourn Moved by Bret Vandelune and seconded by Jeff May to adjourn the meeting. The motion carried unanimously. Meeting adjourned at 1:57 p.m.

5 ITEM 4 MEMORANDUM April 9, 2019 To: From: Re: WRA Technical Committee Operating Contractor Staff WRF Digester HVAC Improvements - Recommendation The WRF has three digester control buildings that house electrical equipment, digester heat exchangers, and digester operational equipment for all six of the digesters. The buildings have a Class 1, Division 1 classifications which require all equipment installed be explosion-proof equipment. The ventilation equipment that services the digester controls buildings are over 30 years old and have been repaired many times over the years. The location of the equipment installation is high in the air, and equipment access is difficult with the existing installation. The WRF Digester HVAC Improvements includes modifications and replacement of existing HVAC make-up air units, heat exchangers, pump and accessories in and around the three digester control buildings, light fixture replacement in the digester building access tunnels, and other incidental items. The engineer s estimate for this project is $457, and bids will be taken on Tuesday, May 7, The bids will then be presented to the WRA Technical Committee at the May 14, 2019 meeting for review and recommendation to the WRA Board for consideration at the May 21, 2019 meeting. The final completion date for the improvements is October 18, 2019, and the project will be funded through the WRF Facilities Rehabilitation project code (WR118).

6 ITEM 5 MEMORANDUM April 9, 2019 To: From: Re: WRA Technical Committee Operating Contractor Staff WRA West Des Moines Outfall Sheeting Repairs In 2009 the WRA West Des Moines Outfall, Phase 13, Segment 7 project was constructed which consisted primarily of 54-inch reinforced concrete pipe. A significant portion of the project extended along the Raccoon River south of Commerce Drive in West Des Moines. As part of the project, the contractor installed sheet piling to protect the sewer from erosion in the areas where the sewer was constructed very close to the Raccoon River. Approximately two years later in January of 2011 the WRA identified an area of the sheeting that failed. The WRA determined that the sheeting was installed in accordance with the contract documents under the original project and that flooding of the Raccoon River caused erosion of the soil on the river side of the sheeting and saturation of the soils on the land side of the sheeting. This condition resulted in excessive loading of the sheeting causing a portion of it to fall into the river. The portion of the WRA sewer behind the area of failed sheeting was at risk of washing out in the event of a subsequent flood event along the Raccoon River. In January of 2011 the WRA entered into an emergency contract to repair the portion of the sheeting that had failed. While the emergency work was being completed the WRA identified additional areas where the sheeting needed to be reinforced to avoid future failure. The WRA contracted under a separate project to have structural supports added to the existing sheeting to avoid future failures. The structural supports were extended to a point where it was believed that the current of the river would no longer cause erosion leading to failure of the sheeting. In March of 2019 the Raccoon River reached flood stage and the waters of the Raccoon River extended over the top of the sheeting referenced above. Once the waters receded the WRA identified an area of sheeting that failed similar to the failure in Upon reviewing the pattern of the river over the past 8 years it is evident that the river bank has eroded beyond what the point the WRA had anticipated in The failure identified in 2011 occurred immediately beyond the last structural support installed in The section of the WRA sewer, including a manhole, located in the area of the recent failure is now at significant risk of washing out. The Operating Contractor s Staff is in the process of developing an emergency project to repair the area of failed sheeting. The emergency project will include replacement of the failed sheeting and installation of structural supports. The Operating Contractor has not yet completed a design for the emergency repair but anticipates the cost to be approximately $175,000.

7 ITEM 5 In addition to the emergency project, the Operating Contractor is developing a follow-up project to include installation of structural supports along all reaches of sheeting that were installed in the original 2009 sewer project to reduce the likelihood of future failures of the sheeting. The project to install additional structural supports will extend approximately 5,800 linear feet. The Operating Contractor has not yet completed a design for this project but anticipates the cost to be approximately $600,000. The Operating Contractor is working toward completion of the design and bidding of the emergency project as well as the follow-up project for structural supports and would like to proceed with construction of the projects as quickly as possible. Figure 1: April 1, 2019 West Des Moines Outfall Sheeting Failure

8 Location of Sheeting Failure WRA 54" West Des Moines Outfall Sanitary Sewer oo cc Ra 5 n Ri ve r Interstate 3 WRA West Des Moines Outfall Sheeting Repair Feet