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Notice of Decision 2003 Northampton Department of Public Works BRP WS 24,Transmittal#W035381 PWS m#1214000 Proposed Mountain Street Water Treatment Plant Based on the information submitted, the Department, acting under the authority of Chapter 111, Section 17 of the Massachusetts General Laws and 310 CMR 22 Massachusetts Drinking Water Regulations, hereby grants provisional approval for Northampton to construct the proposed WTP, subject to the following conditions, requirements and comments. Many of the conditions listed below were also included in the Department's 1996 approval and either still apply or have not been addressed in the revision. I. As shown on the plans, the overflow pipe from the clearwell is hard-piped to the equalization tank prior to the lagoons. The Department notes that a notation has been added to the Plans that the overflow structure will be designed by the tank manufacturer based on a 6.5 MGD flow rate. The filtered water wetwell overflow pipe is also piped directly to the equalization tank. In addition, the maximum water level in the equalization tank is 1.25 feet higher than the overflow weir in the filtered water wet well. The overflow pipe from the clarifier is connected to the overflow pipe from the filtered water wet well but is more than 6 feet higher. Both these connections will potentially allow non-filtered water to flow into the filtered water wet well. According to the Department's 2001 Guidelines and Policies for Public Water Systems (the "Guidelines"), Section 8.0, all overflow pipes must terminate at an elevation between 12 and 24 inches above the ground surface, located such that any discharge is visible and cannot be directly connected to a storm drain. The Department requires that these overflow pipes be terminated above the ground surface with the ends screened in accordance with the Guidelines. 2. Although not shown on the plans, the Department understands that a piping arrangement exists that will allow the raw water line from the Ryan Reservoir to be physically disconnected once the treatment plant is on-line. The Department requires that a physical disconnect be made between any raw water and finished water piping and that a plan showing this arrangement be submitted. The Department recommends that a spool piece be included in the design, which if inserted,may allow for the treatment plant to be bypassed in the case of an emergency. 3. The Department requires that bacteria and Volatile Organic Compounds (VOC)samples be collected for analysis from the clearwell before the WTP is placed on-line. 4. Enclosed as Attachment B is a copy of the Department's guidance document on the preparation of an operations and maintenance manual for treatment facilities. This manual must be developed and a copy submitted to the Department before the WTP is placed on-line. 5. Based on the submitted plans,the Department has assigned a preliminary rating to the facility as a Class IB-T water treatment plant according to the attached facility rating sheet, enclosed as Attachment C. A final rating will be assigned upon completion of the facility. Based on the Department's regulations, 310 CMR 22.1IB, the facility must be staffed a minimum of eight hours per day, including weekends, when the plant is in operation'. The primary operator of the facility must possess a Grade 3-T license or better and the secondary operator must possess a Grade 2-T license or better. The Department notes that provisions have been included on the plans for the future addition of an ozonation system. The addition of ozone (or ultraviolet disinfection) will increase the ratings points assigned to the facility and will result in the plant being rated as a Class IV-T WTP. As a IV-T facility, the plant must be staffed a minimum of 16 hours per day and the primary operator must possess a Grade 4-T license. 6. In accordance with the Guidelines, Section 6.1, chemicals related to water supply treatment must be stored in a bermed area capable of containing 110% of the volume of chemicals. Based on the submitted plans, there does not seem to be adequate containment for the alum and sodium hypochlorite chemicals. Also, there appears to be conflicting information of the curb height for This assumes that a staffing reduction request is approved by the Department. 2 PT ROMNEY rernor RRY HEALEY utenant Governor COMMONWEALTH OF MASSACHUSETTS EXECUTIVE OFFICE OF ENVIRONMENTAL AFFAIRS DEPARTMENT OF ENVIRONMENTAL PROTECTION 436 Dwight Street•Springfield,Massachusetts 01103• (413)784.1100 George Andrikidis,P.E. Northampton Department of Public Works 125 Locust Street Northampton,MA 01060 ELLEN ROY HERZFELDER Secretary EDWARD P KUNCE Acting Commissioner March 24, 2003 RE: NORTHAMPTON DWP Northampton Department of Public Works PWS ID# 1214000 ACO-WE-01-5014 Notice of Decision-BRP WS 24 Provisional Approval to Construct Facility> 1 MGD Proposed Mountain Street Water Treatment Plant Transmittal#W035381 Dear Mr.Andrikidis: The Department of Environmental Protection (the "Department") is in receipt of a set of plans and specifications detailing the construction of the 6.5 million gallon per day (MGD) Mountain Street Water Treatment Plant (WTP), submitted on your behalf by Metcalf & Eddy. The Department provisionally approved the original design of the WTP in 1996. Attachment A is a copy of the Department's February 12, 1996 approval letter, which includes a detailed description of the proposed WTP. The current design was submitted in accordance with the Administrative Consent Order (ACO) (referenced above)between the Department and the City, and reflects the final planned redesign of the facility. In general,the current design is essentially the same as the original design, with some modifications. As summarized in your submittal,the following modifications were made: 1. The lagoon layout was redesigned to relocate the lagoons further away from Mountain Street. In addition,a landscaping buffer plan has been added to minimize visual impacts from the street. 2. The design was updated to conform to the latest codes, technology, and manufacturers. The updated codes include the Massachusetts Building Code, HVAC codes, and National Electric Code. 3. A fire pump and sprinkler system to the WTP building was added. 4. The zinc orthophosphate system was eliminated since the City now operates a separate corrosion control facility downstream of the proposed WIT. 5. Sodium hypochlorite is now proposed in lieu of gaseous chlorine, due to the risk management planning associated with the storage of gaseous chlorine on site. 6. The original chlorine contact tank is no longer proposed. As a result, the clearwell has been redesigned to provide additional storage to meet the disinfection contact time (CT)requirements at the WTP. This information is oval able In alternate format.Call Aprel McCabe,ADA Coordinator at 1ti7-5561171.TDD Service 1-000-1983307. DEP on the World Wide Web_ http.//www.mass.9ov/dep 0 Printed on Recycled Paper Northampton Department of Public Works BRP WS 24,Transmittal#W035381 P W S ID#1214000 Proposed Mountain Street Water Treatment Plant In light of potential TTBIM exceedances,the Department requires that the above-mentioned comments be taken into account and the size of the 4.0 MG tank be reconsidered. Any revised plans reflecting a reduced tank size must be submitted to the Department. If the City chooses not to reduce the size of the cleat-well, then detailed information regarding CT calculations and assumptions must be submitted prior to construction of the WTP as well as information demonstrating that the City's ability to meet the requirements of the Stage I and proposed Stage 2 Disinfectants/Disinfection Byproduct Rules will not be jeopardized. 11. The Department requires that a tracer study be performed on the clearwell before the WIT is placed on-line to verify the efficiency of the baffling within the tank. A proposal will not be required if the study is conducted in accordance with the EPA Surface Water Treatment Rule Guidance Manual. Results of the study must be submitted to the Department. 12. In accordance with section 5.9 in the Guidelines, a commitment for the disposal of facility residuals must be made prior to the plant being approved by the Department. This commitment must include securing all necessary local permits. The Department requires that a plan for disposal of lagoon residuals be submitted and that all applicable local permits be secured. 13. There appears to be no specification for a continuous chlorine residual analyzer The Department requires that a specification for a continuous chlorine residual analyzer be submitted. 14. There are a number of errors on the plans regarding items that have been changed since the 1996 design. For example, there are references to the zinc orthophosphate feeds on sheet M-4. Sheet C-8 shows the flowmeter chamber including details on chlorine gas injection and zinc orthophosphate. The instrumentation sheet I-2 still shows a chlorine contact tank as part of the instrumentation. The Department requires that the plans be corrected. 15. Regarding other permits and project requirements,the following comments are noted: • A NPDES general permit issued by the EPA in 1996(No.MAG640034)needs to be renewed (all NPDES permits must be renewed every five years). • Regarding the Environmental Notification Form(ENF) that was filed for the WTP in 1994, a Notice of Project Change must be submitted, as construction has not commenced within five years of filing. • As a condition of the Drinking Water State Revolving Fund program, a Project Evaluation Report (PER) must be submitted. A PER must present project alternatives, the cost effectiveness of the project and the basic design parameters. There are also requirements for public meetings and hearings on the proposed project. More details on the PER can be found in the Department's DWSRF application package. The Department will not issue final approval of the WTI' until these provisions are satisfied. In addition, any deviation from the current design affecting capacity, hydraulic conditions, operating units, or the quality of water to be delivered, must be approved by the Department. Based on the review of the WTP plans and specifications, the Department notes the following general comments and items for consideration: 1. The Department understands that provisions for the future installation of ultraviolet disinfection (UV) will be designed as part of this project and the current provisions for ozone would be removed. This is not reflected in the plans. (Ozone provisions are still included.) 2. Due to heightened awareness about security issues, the Department recommends that the entire WTP area be enclosed within a security fence. 4 Northampton Department of Public Works PWS ID#1214000 BRP WS 24,Transmittal#W035381 Proposed Mountain Street Water Treatment Plant the sodium hypochlorite storage area between sheets M-9 and S-4. The Department requires that the plans be revised to provide 110% containment in the alum and sodium hypochlorite storage rooms. 7. The percolation test rate at the proposed soil absorption system is reported as 60 minutes per inch. This percolation rate does not meet the Department's Title 5 regulations, 310 CMR 15.000, as currently written although the maximum allowable percolation will be increased to 60 minutes per inch as of January, 1, 2004. Under current Title 5 regulations, a Title 5 permit cannot be issued for the proposed soil absorption system. Therefore,the Department requires that a new percolation test be conducted and the soil absorption system moved to a location that meets Title 5 requirements. 8. As shown on the plans, discharges from all operations building first floor floor-drains and lab sinks (including the residual analyzer discharge) are directed to the facility's septic system. Based on the Department's Title 5 regulations, 310 CMR 15.004,these proposed discharges to the septic system are not allowed. These discharges should be directed to the proposed lagoon system. The Department requires that plans reflecting these changes be submitted. 9. As mentioned in recent correspondence between the City and Northampton, piloting of the proposed granular activated carbon system will be required in accordance with the original 1995 proposal and conditions. The full-scale piloting is proposed to be performed after the plant is in operation for at least 3 months. The Department requires that an updated schedule for the GAC pilot be submitted before the WTP is placed an-line. 10. The cover letter submitted with the permit application stated that the clearwell size has been increased from 3.0 MG to 4.0 MG to accommodate the removal of the chlorine contact chamber and to provide properly disinfected water to the WTP. The clearwell has also been baffled to increase tank efficiency in order to improve disinfection contact time (CT). The Department has the following comments regarding the clearwell size and CT considerations: • The City currently has an approved watershed protection plan(WPP) and would therefore be eligible to receive a %-log credit towards disinfection, if the plan is going to continue to be implemented in the future. Since the treatment plant will be granted a 2.0-log credit, the City would then be required to provide 1/2-log credit through disinfection(3.0-log total inactivation of Giardia is required). • The plans indicate that soda ash is to be injected upstream of the clearwell. In terms of CT calculations, a lower pH would result in better CT effectiveness. Injecting soda ash to the water as it leaves the tank would therefore be recommended. • The most recent jar testing results submitted by Metcalf& Eddy(dated December 23, 2002) show the potential of the treated water to form high total trihalomethanes (TTHM) during the summer season. Although the tests were based on conservative assumptions (e.g., high holding times, temperatures, etc.), the tests show that there is the potential for high TTHM formation with longer detention times. • If the clearwell tank efficiency is assumed to be at least 50%, the Depathnent calculates that the required volume of the tank for a 1-log removal efficiency, is approximately 1.4 MG' This also assumes that CT will be met for water leaving the tank and does not take into account,additional CT gained in the transmission mains. The Department also notes that if the City is granted a 1/2-log credit for the WPP and soda ash is injected after the water leaves the tank,the required volume would be significantly lower. 2 Other assumptions: Minimum chlorine at end of tank=0.5 mg/L,temperature=0.5°C,pH=7.5,CT99.9(1-log) =79 mg/L*min,Qpeak=6.5 MGD. 3 Northampton Department of Public Works PWS ID#1214000 BRP WS 24,Transmittal#W035381 Proposed Mountain Street Water Treatment Plant 3. The plans show a control valve on the 24-inch Ryan raw water line to be installed underground with the motor mounted on a floor stand above ground in the lawn area behind the building. Consideration should be given to installing this motor-operated control valve in a vault or in the WTP. 4. A reduction in the size of the clearwell described in paragraph #10 above, might lead to cost savings on this project. Furtheunore, the goal of potable water at the treatment plant(the first user) appears to be achievable by other means. In addition, cost-effectiveness is of interest to the Drinking Water State Revolving Fund. The Department would be willing to meet with you and your consultant for further discussions on the contents of this letter. If you have any questions or would like to arrange a meeting, please contact Eva Tor at(413) 755-2295 or Mike McGrath at(413)755-2202. Sincerely, Michael G Regional Director Department of Environmental Protection Western Regional Office s� v w:\brp\ws\permits\water treatment plants\Northampton Water Treatment Plant Approval.doc Attachments: A—Department's February 12, 1996 Provisional Approval Letter B—O&M Manual Guidance C—Water Treatment Facility Rating Worksheet cc: Mayor Mary Clare Higgins,City Hall,210 Main Street,Northampton,MA 01060 with Attachment A Rhonda Pogodzienski,Metcalf&Eddy,30 Harvard Mill Square,P.O.Box 4071,Wakefield,MA 01880 with all Attachments Northampton Board of Health,City Hall,210 Main Street,Northampton,MA 01060 Charles Borowski,Northampton Water Department,237 Prospect Street,Northampton,MA 01060 with all Attachments DEP/DWP Boston with Attachment A Don St.Marie—DEP/MS Boston with Attachment A Eva Tor—DEP/DWP WERO with all Attachments Mike McGrath—DEP/DWP WERO