DDW-2024-011894

October 9, 2024
Kaymar Willis
Antimony Town
PO Box 120083
Antimony, Utah 84712
Subject:Conditional Plan Approval, Well Equipping, Antimony Town Well (WS003), Arsenic Removal Treatment Plant (TP003); Antimony Town, System #09001, File #12894
Dear Kaymar Willis:The Division of Drinking Water (the Division) received the plans and specifications for equipping the Antimony Town Well and Arsenic Removal Treatment Plant from your
consultant, Kelly Chappelland Ensign Engineering on January 23, 2024. The Division issued Plan Approval for drilling Antimony Town Wellon July 14, 2022. Review comments were sent on
February 7, 2024, August 20, 2024, and September 10, 2024; revised plans were received on August 16, 2024, September 10, 2024, and September 18, 2024.
The letter includes the following sections and addenda:

1. Project Summary forArsenic Removal Water Treatment Plant (TP003)    
2. Plan Approval for Arsenic Removal Water Treatment Plant (TP003)
3.  Operating Permit Checklist 
4. Project Overview (Addendum 1)
5. Future Monitoring and Reporting Requirements (Addendum 2)
Our understanding of the project includes the following:
The project includes the construction of one drinking water well pump house for the Antimony Town Well consisting of a masonry pump house with asphalt shingle roof, a 100 gallon per
minute (gpm) submersible pump and 15 horsepower (HP) motor, piping, valves, treatment system equipment, HVAC, electrical, SCADA, security system, paving, site work, landscaping, fencing,
and other associated items and appurtenant work. A transfer switch is planned in the event of power failure.
The well was pump-tested at 200 gpm. The 100-gpm pump has a total dynamic head of 380 feet.
The Antimony Town Well is identified as WS003 in the Division’s database. The laboratory analytical results from the initial source sample results were received. The results indicate
that the source exceeds the primary and secondary maximum contaminant level (MCL) for arsenic and aluminum, respectively. Arsenic and aluminum results are 0.0326 milligrams per liter
(mg/L) or parts per million (ppm) and 0.3 ppm, respectively. Arsenic is the target chemical for treatment since it exceeds the primary drinking water standard. A secondary drinking water
standard regulates aluminum.
The proposed Arsenic Removal Water Treatment Plant is identified as TP003 in the Division’s database.
Pilot and bench testing was performed to determine the design criteria for treating the Antimony Town Well (WS003). The treatment system will include pre-oxidation, coagulation, co-precipitation,
and manganese dioxide filtration.
The chlorination system includes the following:
The chlorination system includes a liquid sodium hypochlorite feed system (Watson Marlow Qdos 20).
The chlorinator will add chlorine to the water from Antimony Town Well (WS003).
The chlorinator is intended to provide pre-oxidation and secondary disinfection in the distribution system.
The chlorinated water will go to the East Bench 100,000 Gallon Tank (ST004).
The proposed sodium hypochlorite for disinfection meets the ANSI/NSF 60 standard.
The proposed design target dose of 2.0 mg/L or ppm (measured as free chlorine) is based on a typical flow of 100 gpm from the Antimony Town Well (WS003). It is anticipated that 0.5 ppm
will remain as a residual after pre-oxidation.
An automatic flow-paced control will adjust the chlorine dose based on the speed of the well pump.
The Point of Entry (POE) sampling location will be from a Hach OAE NSF 61 Residual analyzer pulling directly from the well discharge piping within the pumphouse.
Backwash waste will be directed to an on-site detention pond near the treatment plant. Antimony Town has applied for construction and groundwater discharge permits through the Division
of Water Quality.
A T-1-certified operator will be required to operate the treatment system which is appropriate based on the system being classified as a community water system with a population under
500. Please contact Dawnie Jacobo at 385-272-5038 or [e-mail] for questions related to operator certification.
The chlorinator is identified as a process within the Arsenic Removal Water Treatment Plant (TP003) in the Division’s database.    
Detailed project description and the Division’s decision to issue Plan Approval for the TP003 treatment plant is summarized in the Project Overview Addendum.
We have received the following information for the Antimony Town Well (WS003) and the Arsenic Removal Water Treatment Plant (TP003):
Certification of well seal.
Well driller’s report (well log).
Aquifer drawdown test results (step drawdown test and constant-rate test).
New Source Chemical Analysis of the well water.
Plans and specifications for equipping the well.
Pump information.
Wellhead discharge piping.
Well house design.
Chlorinator design/plans/specs for Antimony Town Well (WS003).
Filtration design/plans/specs for Antimony Town Well (WS003)
Plan Approval, Monitoring, and Secondary Disinfection requirements
We have completed our review of the plans and specifications, stamped and signed by Kelly L. Chappell, P. E., and dated September 10, 2024, and find they basically comply with the applicable
portions of Utah’s Administrative Rules for Public Drinking Water Systems in R309. On this basis, the plans for equipping Antimony Town Well and installation of Arsenic Removal Water
Treatment Plant (TP003)are hereby approved subject to the following conditions:
Signage will be placed on the wall adjacent to each tank identifying the chemical tanks and another tag placed on each feeder line at the injection location.

Personal protective equipment will be provided for hazardous material handling.
The feeder lines will be mounted to the west and south walls rather than the ceiling.
Appropriate secondary containment for stored chemicals.
This approval pertains to construction only. An Operating Permit must be obtained from the Director before Antimony Town Well (WS003) and Arsenic Removal Water Treatment Plant (TP003)
may be put into service. A checklist outlining the well approval process, including the items required for issuing an operating permit for this well is enclosed for your information.
Enclosed please also find an Operating permit Checklist for other components of this project.Approvals or permits from the local authority or county may be necessary before beginning
construction of this project. As the project proceeds, notice of any changes in the approved design, as well as any change affecting the quantity or quality of the delivered water, must
be submitted to the Division. We may also conduct interim and final inspections of this project. Please notify us when actual construction begins so that these inspections can be scheduled.
This approval must be renewed if construction has not begun or if substantial equipment has not been ordered within one year of the date of this letter.
Monitoring Requirements
The monitoring requirements for this treatment plant include one sample on the same day at the pre-treatment tap and the finished water tap. The samples should be submitted for analysis
by an appropriate EPA method to determine arsenic and aluminum concentrations in drinking water at startup. Then, as part of the Operating Permit, monthly samples will be required for
six months. After that, the monitoring schedule will be evaluated for a quarterly schedule. If you have any questions, please contact David B. Kruse at 385-566-7789 or [e-mail].
Secondary Disinfection Requirements
The Antimony Town water system is not required to disinfect the Antimony Town Well (WS003) based on bacteriological source sample results currently available. The water system is
electing to install the Arsenic Removal Water Treatment Plant (TP003) which includes pre-oxidation to provide a detectable disinfectant residual in the distribution system for secondary
disinfection.
The plan review of the proposed Arsenic Removal Water Treatment Plant (TP003) is based on providing secondary disinfection. When this chlorinator is installed and placed in operation
after the Operating Permit issuance, the Antimony Town Well (WS003) will be required to demonstrate ongoing compliance with the secondary disinfection requirements that will be outlined
in Addendum 2 to this letter.
The Division shall be informed by telephone within 8 hours by a water supplier of the malfunction of any disinfection facility such that a detectable residual cannot be maintained at
all points in the
distribution system per R309-105-18(1)(a).
Please be aware if Antimony Town Well (WS003) is found to require additional disinfection in the future per R309-200-5(7)(a)(i), further regulations will apply. For example, if primary
disinfection is required this will include submitting disinfection CT information showing compliance with 4-log virus inactivation in accordance with the Ground Water Rule in R309-215-16.
If you have any questions regarding this approval, please contact Chris Martin, P.E., of this office, at [phone], or me at [phone].
Sincerely,
Michael Newberry, P.E.
Permitting and Engineering Support Manager
CM/mrn//mdbEnclosuresWell Approval ChecklistOperating Permit ChecklistAddendum 1 - Project OverviewAddendum 2 - Future Monitoring and Reporting Requirementscc:Jeremy Roberts, Southwest
Utah Health Department, [e-mail] Chappell, P.E., Ensign Engineering, [e-mail] Gadd, Ensign Engineering, [e-mail] Jewkes, Ensign
Engineering, [e-mail] Allen, Antimony Town Water System, [e-mail]. Paul Wright, P.E., DEQ District Engineer, [e-mail] Kruse, Division
of Drinking Water, [e-mail] Treutel, Division of Drinking Water, [e-mail] Powers, Community Impact Board, [e-mail] Kolmel, Division of Water Quality,
[e-mail]@utah.govCMartin 09001 12894 WS003_TP003 PA - Equipping and Treatment FacilityDivision of Drinking WaterChecklist for New Public Drinking Water Wells
(Per Utah Administrative Code, Rule R309-515-6)
System Name:System Number:Well Name & Description:1.Approval to Drill the Well
☐Project Notification Form (PNF)
☐Preliminary Evaluation Report (PER) concurrence
☐Well drilling specifications and plans
☐Valid Start Card or authorization to drill letter from the Division of Water Rights2.Approval to Equip the Well
☐PNF (if the well drilling and well equipping are designed by different consultants)
☐Well location data
☐Certification of well seal
☐Well driller’s report (well log)
☐Aquifer drawdown test results (step drawdown test & constant-rate test) for well yield determination
☐Chemical analyses of the well water
☐Plans and specifications for equipping the well
☐Pump information (e.g., pump specifications, pump curve & operating point, motor information, etc.)
☐Well head discharge piping
☐Well house design3.Operating Permit to Introduce the Well Water
☐Documentation of valid water right(s)
☐Recorded land use agreements, or documentation that the requirements for coverage under the City/County source protection ordinance have been met
☐Design engineer’s certification of conformance with plan approval conditions
☐Design engineer’s certification of rule conformance for any deviation from approved plans
☐As-built or record drawings
☐Evidence of O&M manual delivery to system owner☐Satisfactory bacteriological results as evidence of proper flushing and disinfection
Utah Division of Drinking Water ― Checklist for Issuing Operating PermitsWater System Name:System Number: Project Description:File Number:
Items 1 through 8 below must be submitted to the Division and found to be acceptable prior to operating permit issuance (unless a water line project meets the requirements of R309-500-7
and is not required to obtain an Operating Permit).
Distribution lines (not including in-line booster pump stations) requiring Plan Approval may be placed into service prior to submitting all of the following items and receipt of Operating

Permit if the water system has received items 1 and 4 below.☐1.Certification of Rule Conformance by a professional engineer (P.E.) that all conditions of Plan Approval were accomplished,
and if applicable, changes made during construction were in conformance with rules R309-500 through 550☐2.As-built or record drawings incorporating all changes to approved plans and
specifications (unless no changes were made to the previously approved plans during construction)☐3.Confirmation that as-built or record drawings have been received by the water system☐4.Satisfactory
bacteriological samples as evidence of proper disinfection and flushing in accordance with the appropriate ANSI/AWWA standards:
☐ANSI/AWWA C651-14 AWWA Standard for Disinfecting Water MainsTwo consecutive sample sets at least 16 hours apart, none positive (every 1200 feet, end-of-line, each branch, etc.)☐ANSI/AWWA
C652-11 AWWA Standard for Disinfection of Water-Storage FacilitiesOne or more samples, none positive☐ANSI/AWWA C653-13 AWWA Standard for Disinfection of Water Treatment PlantsTwo consecutive
samples per unit, none positive, no less than 30 minutes apart☐ANSI/AWWA C654-13 AWWA Standard for Disinfection of WellsTwo consecutive samples, none positive, no less than 30 minutes
apart☐5.Water quality data, where appropriate [For example, water quality data showing MCL compliance; raw and finished water data that demonstrate satisfactory performance of the new
treatment facility.]☐6.If applicable, all other documentation that may have been required during the plan review process☐7.If applicable, confirmation that the water system owner has
received the O&M manual for the new facility☐8.If applicable, location data of new storage tank, treatment facility, or sourceADDENDUM 1Project Overview
Antimony Town Water System (UTAH #09001)
Arsenic Removal Water Treatment Plant (TP003)
Our understanding of the project includes the following:
The Antimony Town Well is identified as WS003 in the Division’s database. The laboratory analytical results from the initial source sample results were received. The results indicate
that the source exceeds the primary and secondary maximum contaminant level (MCL) for arsenic and aluminum, respectively. Arsenic and aluminum results are 0.0326 milligrams per liter
(mg/L) or parts per million (ppm) and 0.3 ppm, respectively. Arsenic is the target chemical for treatment since it exceeds the primary drinking water standard. A secondary drinking water
standard regulates aluminum.
Pilot and bench testing was performed to determine the design criteria for treating the Antimony Town Well (WS003).
The treatment system will include pre-oxidation, coagulation, co-precipitation, and manganese dioxide filtration. A detectable residual will be provided for secondary disinfection.The
proposed Arsenic Removal Water Treatment Plant (TP003) has a plant design capacity of 200 gallons per minute (gpm). The design includes 1train of four pressure filters with manganese
dioxide media. The proposed treatment plant consists of the following processes in sequence:Pre-oxidation – by sodium hypochlorite addition; dosing at an estimated 2 ppm; 1 train; 100
gpm per trainpH Adjustment – by 15% hydrochloric acid solution fed at 10 to 12 ppm to achieve a pH of 7. Feed rate will be approximately 1 gallon per hour (gph).
Coagulant Addition - by ferric chloride fed at 2 ppm.
Media filtration – Four (4), 24-inch pressure filters will be installed with 42-inches of ANSI/NSF-approved Pyrolox Advantage media. The design filter loading rate is approximately 8
gpm per square foot (gpm/ft2).
All treatment chemicals used will have ANSI/NSF 60 certification.
A 15% hydrochloric acid solution will be fed at 1 gallon per hour at 10 to 12 ppm for pH adjustment.
Ferric chloride will also be fed to promote coagulation and filtration of arsenic at a dose of approximately 2 ppm.
Secondary Disinfection - by sodium hypochlorite addition, residual of 0.5 ppmBackwash Water – supplied by the East Bench 100,000 Gallon Tank (ST004).
The backwash will be initiated primarily based on the filter run time of approximately 24 hours. A pressure differential switch is also provided as a backup. A backwash is triggered
if the pressure differential reaches 7 psi. The Antimony Town Well (WS003) will be used as the source for the backwash supply.
Redundancy is provided through a spare chemical pump, valves, and controllers kept on the shelf in case of a breakdown. Also, each vessel can be taken offline to operate at 75% capacity.
The well pump can operate at 75% capacity through a variable frequency device. Also, the spring sources provide enough capacity at this time to meet the system demands.
The filtration media will require sieve analysis testing every 5 years to determine compliance with manufacturer recommendations. Anticipated media life is approximately 20 years.ADDENDUM
2
Future Elective Monitoring and Reporting Requirements
Chlorine Monitoring & Reporting Requirements
The water system will be required to meet elective disinfection requirements once this facility is installed and operating. As a part of these requirements, the water system will need
to continuously maintain a minimum free chlorine residual at each chlorinator Point of Entry (POE) into the system and demonstrate a detectable chlorine residual in the distribution
system. 
Elective Disinfection Requirements and Reporting 
Chlorine Residual ‒ Point of Entry (POE) to Distribution System
The POE sampling location will be identified in the Division’s database. The location will be identified during the plan approval process. Maintain a minimum of 0.2 mg/L residual (measured
as free chlorine) at the POE sampling location. [R309-215-16(3)(b)(iii)(A)(I) and (II)]
The chlorine residual concentration measured at the POE sampling location shall not exceed the maximum residual disinfectant level (MRDL) of 4.0 mg/L (measured as free chlorine). [R309-200-5(3)(c)(iv)]
Record and report the lowest daily chlorine residual concentration, measured as free chlorine, at the chlorinator POE sampling location a minimum of daily. [R309-210- 8(3)(a)(ii)]
Our records show that your water system serves 135 people. Please be aware that R309-215-16(3)(b)(iii)(A)(II) requires water systems serving 3,300 people or fewer to monitor the POE
chlorine residuals and take daily grab sample(s). Alternatively, instead of taking daily grab samples, a groundwater system serving 3,300 or fewer people may choose to use an online
analyzer to continuously monitor the POE chlorine residuals entering the distribution system.
Chlorine Residual ‒ Distribution System (DS001)
This water system must maintain a detectable residualthroughout the distribution system. It is recommended to maintain the chlorine residual above 0.1 ppm in the distribution system.
[R309-520-5]
The chlorine residual measured in the distribution system shall not exceed the maximum residual disinfectant level (MRDL) of 4.0 mg/L (measured as free chlorine). [R309-200-5(3)(c)(iv)]
This water system must take a minimum of three (3) chlorine residual samples per weekat varying locations throughout its distribution system (DS001). [R309-105-10(1)(c)]
Distribution system chlorine residuals must be taken in conjunction with total coliform sampling. [R309-215-10(3)]
Disinfection Report Submission
To demonstrate ongoing compliance with elective disinfection requirements, the water system must complete monthly operational reports for each active chlorinator using a template approved
by the Division. 
Operational reports are submitted quarterly. The reports are due to the Division by the 10th day following the end of each reporting month or quarter (i.e., January 10th, April 10th,
July 10th, and October 10th for quarterly reports). The reports can be submitted by hardcopy, fax, or email at [e-mail]. Please contact Luke Treutel at [phone] or [e-mail]

to schedule training regarding proper reporting. 
In addition to monthly disinfection reporting, this water system must submit the monthly average of chlorine residual samples taken in the distribution system. Distribution system chlorine
residual monitoring results are due quarterly by the same compliance dates as the monthly disinfection report and can be submitted via an online form found at mrdl.utah.gov. 
Records must be maintained for a minimum of 5 years. [R309-105-17(1)]