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HomeMy WebLinkAboutW-2023-0590A_Oshkosh_Temporary Blended Phosphate Chemical Feed Equipment_Approval March 13, 2024 DIANE BARTLETT CLERK Acknowledgement of Receipt CITY OF OSHKOSH 215 CHURCH AVE PO BOX 1130 OSHKOSH WI 54903-1130 Project Number: PWSID#: DNR Region: County: W-2023-0590A 47104574 NER WINNEBAGO SUBJECT: WATER SYSTEM FACILITIES PLAN AND SPECIFICATION APPROVAL Dear Ms. Bartlett: The Wisconsin Department of Natural Resources, Division of Environmental Management, Bureau of Drinking Water and Groundwater, is conditionally approving plans and specifications for the following project. An engineering report or information of sufficient detail to meet the requirements of s. NR 811.09(3), Wis. Adm. Code, was submitted along with the plans and specifications. Water system name: Oshkosh Waterworks Date received: 03/12/2024 Engineering firm: Donohue & Associates, Inc. Professional Engineer: Susan Wojtkiewicz Regional DNR Contact: Jamie Douglas, 3369 West Brewster Street, Appleton WI 54914-1602, (920) 362-6629, jamie.douglas@wisconsin.gov DNR Plan Reviewer: Bradley Siefker, 101 South Webster Street, Madison, WI 53703, (608) 419-7636, bradley.siefker@wisconsin.gov Project description: On behalf of the City of Oshkosh (City), Donahue & Associates, Inc. has submitted revised plans and specifications for a temporary blended phosphate chemical feed pump at the water treatment plant (WTP). The plans and specifications are hereby approved by the department subject to the conditions below. Background: The water supply system for the City of Oshkosh presently includes a surface water treatment plant drawing raw water from Lake Winnebago, three finished water clearwells, four elevated storage tanks, and the distribution system composed of two pressure zones. The water treatment plant includes two treatment trains that each include rapid mix, flocculation, sedimentation, dual media gravity filtration, ozone contactors, and granular activated carbon contactors. Chemical addition consists of gas chlorine and ammonia to form chloramines for disinfection purposes, fluorosilicic acid for community dental health purposes, blended phosphate for distribution system corrosion control purposes, and sodium hydroxide for pH adjustment and distribution system corrosion control purposes. The proposed project will optimize CCT at the City of Oshkosh’s WTP. On May 31, 2019, the department issued a modification requiring the City to complete a CCT study. The City submitted a corrosion control study report in response to the department’s CCT study requirement on December 17, 2021. Based on desktop and demonstrative CCT studies completed from 2019 through 2021, CCT is optimized, and lead levels are lowest when finished water pH ranges from 7.0 to 7.8 S.U., with a target pH of 7.4 S.U. The target State of Wisconsin DEPARTMENT OF NATURAL RESOURCES 101 S. Webster Street Box 7921 Madison WI 53707-7921 dnr.wi.gov wisconsin.gov Project Number: W-2023-0590A Page 2 of 4 orthophosphate concentration is 2.0 milligrams per liter (mg/L) with an acceptable range of 1.5 to 2.5 mg/L. In the demonstrative study, phosphoric acid was shown to be more effective than the current blended phosphate for corrosion control. The department approved plans and specifications for the new phosphoric acid chemical feed equipment under project number W-2023-0590 and approval letter dated August 11, 2023. Reportedly due to the lead time and procurement issues with the initially proposed equipment, an alternate temporary chemical feed pump is proposed to be used until the previously approved pumps are received and installed. The conditions of the previous approval remain in effect. Phosphoric acid chemical feed system: The two existing blended phosphate chemical feed pumps and storage tanks located within the chemical feed building will be removed and replaced with two new chemical feed systems. Two new Blue White Model No. MD1, maximum 191 gallon per day, electronic positive displacement chemical feed pumps will be used to feed a solution of ANSI/NSF 60 certified 50% active liquid phosphoric acid into the existing meter vault located between the CT/backwash supply tank and the clearwells for distribution system corrosion control purposes. One of the chemical feed pumps will be temporarily installed in the WTP at the current location of the pilot testing equipment, which will be removed. Once the existing blended phosphate chemical feed system has been removed and the other phosphoric acid chemical feed system installed and ready to be placed into service, the temporary installation will be relocated to the permanent location in the chemical feed building. At the minimum 6.5 MGD (4,515 gpm) flow rate and the 2.0 mg/L (as orthophosphate) dose rate, the anticipated chemical feed pump settings will be 10.2% speed (20.5 strokes per minute) with a fixed stroke length, which will be 10.2% of the overall capacity of the pump. The minimum phosphoric acid chemical feed rate will be 0.81 gallons per hour and the estimated daily use will be 19.5 gallons per day based on 24 hours of operation. At the maximum 13.7 MGD (9,515 gpm) WTP flow rate and the 2.0 mg/L (as orthophosphate) dose rate, the anticipated chemical feed pump settings will be 21.6% speed (43 strokes per minute) with a fixed stroke length, which will be 21.6% of the overall capacity of the pump. The average phosphoric acid chemical feed rate will be 1.72 gallons per hour and the estimated daily use will be 41.2 gallons per day based on 24 hours of operation. The chemical feed pumps will be flow paced by a control loop using 4 to 20 mA signals from multiple flow meters, including four flow meters on the GAC contactor effluents. The chemical feed pump discharge piping will be provided with a pressure relief valve, pressure gauge, and adjustable back pressure valve located near the chemical injector in the chemical feed pump discharge piping. The chemical feed pumps will take suction from a new 40-gallon polyethylene chemical solution day tank. The day tank will be filled from a 1,600-gallon polyethylene bulk storage tank. The bulk tank will be provided with new 3-inch diameter CPVC fill lines extending from the existing fill location to the tank. The tanks will be vented to outside the building through CPVC piping that will include a downturned pipe elbow covered with a 24- mesh corrosion resistant screen terminating a minimum of 24-inches above grade. The bulk tank will be provided with a 3-inch diameter CPVC overflow pipe that will include a vapor trap filled with water. The pipe opening will terminate with a downturned pipe elbow covered with a 24-mesh corrosion resistant screen terminating a minimum of 24-inches above the containment basin floor. The tanks will be located within the existing containment basin to provide the required chemical leakage containment. The chemical solution bulk tank will be provided with a radar level sensor, and the chemical solution day tank will be provided with a scale capable of measuring with an accuracy of 0.1 pounds to determine the daily chemical usage. The existing emergency eyewash/shower unit located adjacent to the existing blended phosphate chemical feed system will be connected to the WTP existing tempered water system. The chemical feed pumps will connect to new CPVC discharge lines extending to the WTP building exterior and to the existing blended phosphate chemical injectors within the existing meter vault. Reportedly, the WTP discharge piping includes an existing entry point sample faucet. Project Number: W-2023-0590A Page 3 of 4 Additional lead and copper sampling: Following the water system changes, the City must provide a letter certifying the date on which the chemical feed upgrades have been completed (s. NR 809.55(3)(d), Wis. Adm. Code). The chemical feed system upgrades approved in the Corrosion Control Treatment Study Response letter, dated April 21, 2022, are required to be installed and operational no later than April 21, 2024. As a result of the potential impacts to corrosion in the distribution system, the City will be required to conduct two consecutive 6-month rounds of standard monitoring to evaluate the efficacy of the optimal corrosion control treatment installation. (ss. 809.542(5)(f) and 809.543(6), Wis. Adm. Code). Following a successful monitoring effort, the department will review and assign optimal water quality parameters (OWQPs) which the City will be required to maintain (ss. 809.542(5)(g) and 809.543(7), Wis. Adm. Code). You must notify Alyssa Rosewood before you begin your two- consecutive 6-month rounds of monitoring at alyssa.rosewood@wisconsin.gov. Recommendations: The following recommendations are based on staff review of the project. The owner is not required to implement the recommendations to comply with the approval. 1. The department recommends posting an “Entry Point” sign identifying the finished water sampling faucet. Approval conditions related to Chapters NR 810 and NR 811, Wis. Adm. Code: 1. A resident project representative shall be designated by the water supply owner or by the agent retained by the owner. The resident project representative shall be knowledgeable regarding the proposed construction and be able to ensure the improvements are being constructed in accordance with the department approved plans, specifications, and conditions of the approval. The project representative shall be present on the work site as needed to assure proper construction and installation of the improvements. (s. NR 811.11, Wis. Adm. Code) 2. The electrical outlet for any chemical feed pump shall be clearly marked. (s. NR 811.39 (4)(b), Wis. Adm. Code). The outlet shall be located to allow the chemical pump feed line to be as short as possible in length of run. (s. NR 811.39(7)(a), Wis. Adm. Code) 3. A permanent sign identifying the chemical tank contents shall be posted adjacent to or on chemical storage tanks. (s. NR 811.40(1)(o), Wis. Adm. Code) 4. Compliance with local, state, and federal safety codes, including department of safety and professional services and OSHA codes, for other applicable chemical safety and handling requirements is required. (s. NR 811.40(1)(p), Wis. Adm. Code) 5. Where the eyes or body of any person may be exposed to injurious corrosive materials, suitable facilities for quick drenching or flushing of the eyes and body shall be provided as required in s. SPS 332.15. (s. NR 811.40(2)(e)1., Wis. Adm. Code) 6. Rubber gloves, protective clothing, and safety goggles that form a tight seal with the face shall be provided for each operator who prepares chemical solutions. (s. NR 811.40(2)(e)2., Wis. Adm. Code) 7. The owner or owner’s agent shall provide notification to Jamie Douglas from the department’s Appleton office upon completion of the improvements so that she can inspect the completed improvements and issue written authorization prior to placing the improvements in service if she deems necessary. (s. NR 810.26(1), Wis. Adm. Code) Approval constraints: The project was reviewed in accordance with ss. 281.34 and 281.41, Wis. Stats. for compliance with Chapters NR 108, NR 810, NR 811 and NR 820, Wis. Adm. Code and is hereby approved in accordance with ss. 281.34 and 281.41, Wis. Stats. subject to the conditions listed above. This approval is valid Project Number: W-2023-0590A Page 4 of 4 for two years from the date of approval. If construction or installation of the improvements has not commenced within two years the approval shall become void and a new application must be made and approval obtained prior to commencing construction or installation. This approval is based on the applicant’s representation that the plans and specifications submitted to the department are complete and accurately represent the project being approved. Discovery that the applicant failed to submit complete and accurate plans and specifications may void this approval. Be advised that this project may require permits or approvals from other federal, state or local authorities. For example, a certificate of authority from the Public Service Commission of Wisconsin may be required per s. 196.49, Wis. Stats. and ch. PSC 184, Wis. Adm. Code. Appeal rights: If you believe that you have a right to challenge this decision, you should know that the Wisconsin Statutes and administrative rules establish time periods within which requests to review Department decisions must be filed. To request a contested case hearing pursuant to s. 227.42, Wis. Stats., you have 30 days after the decision is mailed, or otherwise served by the Department, to serve a petition for hearing on the Secretary of the Department of Natural Resources. Requests for contested case hearings must be made in accordance with ch. NR 2, Wis. Adm. Code. Filing a request for a contested case hearing does not extend the 30 day period for filing a petition for judicial review. For judicial review of a decision pursuant to ss. 227.52 and 227.53, Wis. Stats., you must file your petition with the appropriate circuit court and serve the petition on the Department within 30 days after the decision is mailed. A petition for judicial review must name the Department of Natural Resources as the respondent. STATE OF WISCONSIN DEPARTMENT OF NATURAL RESOURCES For the Secretary Bradley D. Siefker, P.E. Public Water Engineering Section Bureau of Drinking Water and Groundwater cc: Brad Rokus – City of Oshkosh (by email) Susan Wojtkiewicz – Donohue & Associates, Inc., Sheboygan (by email) Jamie Douglas – DNR, Appleton (by email) JaNelle Merry – DNR, Green Bay (by email) Brendon Peppard – DNR, Madison (by email) Alyssa Rosewood – DNR, Eau Claire (by email) PSC – Madison (by email)