water treatment system (wts) task work … · appendix a4-1 water treatment system operations and...

WATER TREATMENT SYSTEM (WTS) TASK WORK PLAN

APPENDIX A

PHASE II NON-TIME-CRITICAL REMOVAL ACTION ELIZABETH MINE SUPERFUND SITE

SOUTH STRAFFORD, VERMONT

REVISION NO.: 02

DATE: APRIL 27, 2011

DOCUMENT TRACKING NO.: 83601.WTS.02

http:83601.WTS.02

Water Treatment System Task Work Plan Table of Contents i

WATER TREATMENT SYSTEM TASK WORK PLAN



TABLE OF CONTENTS

Section Description Page No.

1.0 PLAN IDENTIFICATION AND APPROVALS 1

2.0 INTRODUCTION 2 2.1 Reference Plans 2

2.1.1 Program Work Plan 2 2.1.2 Accident Prevention Plan, Quality Assurance Project Plan, and

Construction Quality Control Plan 2 2.2 History 2

3.0 OPERATION AND MAINTENANCE RESPONSIBILITIES 3

4.0 DESCRIPTION, OPERATION, AND CONTROL OF FACILITY 3 4.1 Description of Key Parts of System 3 4.2 General Operation and Maintenance 4 4.3 Performance Testing 4 4.4 Seasonal Commission of WTS 5 4.5 Seasonal Decommissioning of WTS 5

5.0 GREEN AND SUSTAINABLE INITIATIVES 6

LIST OF FIGURES

Figure A2-1 Water Treatment System Location Plan Figure A2-2 Water Treatment System Project Schedule Figure A4-1 Water Treatment System Process Flow Diagram

LIST OF CHARTS

Chart A2-1 Water Treatment System Organization Chart

LIST OF APPENDIX

Appendix A4-1 Water Treatment System Operations and Maintenance Manual

USACE Contract No. W912WJ-11-D-0006 Elizabeth Mine Superfund Site, Document Tracking No.: 83601.WTS.02 South Strafford, Vermont

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Water Treatment System Task Work Plan Table of Contents ii




LIST OF ACRONYMS

AMD Acid Mine Drainage

APP Accident Prevention Plan

CQC Construction Quality Control Plan

ft foot

HD horizontal drain

mg/L milligrams per liter

Nobis Nobis Engineering, Inc.

Northwoods Northwoods Excavating, Inc.

NT Neutralization Tank

NTCRA Non-Time-Critical Removal Action

O&M operation and maintenance

PWP Program Work Plan

QAPP Quality Assurance Project Plan

RCTS Rotating Cylinder Treatment System

ROD Record of Decision

SOP Standard Operating Procedure

SOW Statement of Work

TD toe drain

TP Tailing Pile

USACE U.S. Army Corps of Engineers, New England District

USEPA United States Environmental Protection Agency

WBOR West Branch of the Ompompanoosuc River

Weston Weston Solutions, Inc.

WTS Water Treatment System


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1.0

Water Treatment System Task Work Plan Page 1




PLAN IDENTIFICATION AND APPROVALS

Project Title: Phase II Non-Time Critical Removal Action Elizabeth Mine Superfund Site

Project Location: South Strafford, Vermont

Contract No.: W912WJ-11-D-0006

Task Order No.: 0001

Nobis Project No.: 83601

Prepared By: Brett Kay

Submittal Date: 04/27/2011

Revision No.: 02

4/27/11 Date

APPROVALS:

_____________________________________________ Peter W. Delano, P.E., Program Manager

_____________________________________________ Andrew J. Boeckeler, P.G., Project Manager

_____________________________________________ Patrick McNabb, P.E., Lead Engineer

_____________________________________________ Brett Kay, Project Engineer

4/27/11 Date

4/27/11 Date

4/27/11 Date


2.0 INTRODUCTION

This Task Work Plan was prepared by Nobis Engineering, Inc. (Nobis) to describe the work approach for the operation of the Water Treatment System (WTS) associated with the Phase II Non-Time-Critical Removal Actions (NTCRA) at the Elizabeth Mine Site (Site) located in South Strafford, Vermont. Nobis prepared this Plan for the U.S. Environmental Protection Agency (USEPA) under contract to U.S. Army Corps of Engineers New England District (USACE) through Remedial Action Contract No. W912WJ-11-D-0006, Task Order 0001. This Task Work Plan has been developed based on the August 2, 2010 Statement of Work (SOW) issued by the USACE.

2.1 Reference Plans

2.1.1 Program Work Plan

Refer to the Program Work Plan, prepared by Nobis, for descriptions of the overall project organization, general work approach for the performance of completing the Phase II NTCRA, and the history of response actions and investigations at the Site.

2.1.2 Accident Prevention Plan, Quality Assurance Project Plan, and Construction Quality Control Plan

Work associated with the WTS Task Work Plan will be conducted in accordance with the standalone Accident Prevention Plan (APP), Quality Assurance Project Plan (QAPP), and the Construction Quality Control Plan (CQC) documents prepared by Nobis.

2.2 History

During 2007, historical high iron concentrations were recorded in the toe drains (TD) and horizontal drains (HD) of Tailing Pile (TP)-1. As a result, the USEPA, through the USACE, contracted Weston Solutions, Inc. (Weston) in 2008 to design, construct, and place into service a Water Treatment System (WTS) for treating water discharged from TP-1 TDs and HDs at the Site. The system intercepts and treats acid mine drainage (AMD) exiting the HDs and TDs. The WTS discharge flows to a sedimentation basin, then into a channel, and eventually into Copperas Brook, which is a tributary to the West Branch of the Ompompanoosuc River (WBOR). The overall WTS objective is to reduce AMD impacts to Copperas Brook and the WBOR by removal of elevated metals (primarily iron) from the AMD water. The average combined influent loading is approximately 900 milligrams per liter (mg/L) of total iron. The effluent from the WTS averages less than 5 mg/L of total iron. The system is operated during the construction season, generally between April and November. Figure A2-1 shows the approximate location of the WTS. A schedule for this activity in 2011 is included in Figure A2-2. The schedule for activity in 2012 will be submitted prior to sedimentation basin cleanout in 2012, and will be included as a Figure A2-3. Chart A2-1 contains the staff and subcontractors necessary to operate and maintain the WTS.


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3.0 OPERATION AND MAINTENANCE RESPONSIBILITIES

The successful operation and maintenance (O&M) of the collection, treatment, and discharge system requires careful planning, coordination, and logistics support between Nobis (Prime Contractor), Weston (Engineering Support Subcontractor) and Northwoods Excavating, Inc. (Northwoods, Sitework Subcontractor).

Operators of the WTS are responsible for the following:

Knowing facility operational procedures;

Being familiar with the Water Treatment System Operations and Maintenance Manual (WESTON, 2011) and manufacturers details for proper O&M of WTS components;

Maintaining process equipment in accordance with manufacturers instructions;

Maintaining accurate records for data generated from operations, maintenance, and on-site testing;

Maintaining a log of operating problems regarding the O&M of the WTS;

Implementing and maintaining a strong safety program to insure staff follow proper safety precautions when working at the WTS;

Continuously looking for ways to optimize operations and reduce operating costs; and,

Supporting management in the preparation of operating, maintenance, and capital improvement budgets.

4.0 DESCRIPTION, OPERATION, AND CONTROL OF FACILITY

4.1 Description of Key Parts of System

Five HDs and six TDs on TP-1 are connected to and flow into a manifold which drains AMD by gravity into a pump station wet well. The wet well is comprised of a 6-foot (ft) inside diameter and 7-ft high pre-cast concrete manhole. The pump station is equipped with two submersible pumps and is controlled by a locally mounted duplex control panel. The pump station transfers AMD to the treatment system influent neutralization tank (NT), via 3-inch-diameter high density polyethylene tubing.

The lime feed system is composed of a 1,400 cubic foot storage silo, horizontal transfer conveyor, volumetric feeder, intake funnel and grinder pump. The silo, horizontal transfer conveyor, and volumetric feeder transfer the lime from the silo into the intake funnel. The NT feeds water into the grinder pump and is mixed with influent AMD where lime is added and the solution is re-circulated into the NT to raise the pH of the water. As the water is re-circulated, the retention time increases, which allows for neutralization of the AMD before the water exits via gravity into a Rotating Cylinder Treatment System (RCTS) for additional treatment.

The RCTS serves to aerate the AMD water and oxidize iron present in the process water by two rotating cylinders. Once the fluid level rises above the outlet, water exits the RCTS and is gravity fed to the sedimentation basin. The sedimentation basin allows for settling of iron solids that are precipitated from the water by the neutralization system and RCTS. The sedimentation basin utilizes an outlet structure consisting of four drain pipes. The four drain pipes are set at 2ft depth intervals along the northern side slope to discharge water. An emergency spillway, consisting of an 8-ft weir lined with rip-rap exists on the north east side of the sedimentation


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basin, allows overflow of liquid in case of a plugged outlet, heavy flow and/or rain. The sedimentation basin outlets are diverted into a channel that feeds Copperas Brook and eventually the WBOR. More detailed description of the WTS can be found in the Water Treatment System Operations and Maintenance Manual (Weston, 2011). A complete copy of the O&M manual will be stored at the WTS throughout the duration of work under this Task Order. Figure A4-1 is a process flow diagram of the system.

4.2 General Operation and Maintenance

The O&M of these facilities require personnel that have technical expertise and competence to provide the necessary care and attention needed to meet appropriate environmental quality standards as well as maintain equipment performance and life expectancy. Weston and Northwoods have operated the WTS for the past few years, so they will train multiple new members of on the project team to ensure the appropriate coverage and expertise is available for scheduled inspections and for unscheduled maintenance.

Normal staffing requirements for the facility are estimated to require one part time individual who will monitor the process operations, collect pertinent operational records, and perform necessary maintenance. Periodically two, or more, people will be needed to execute tasks that cannot safely or easily be performed by one person. This would include tasks requiring confined space entry or heavy lifting and equipment operation.

Inspections of the treatment system will be conducted at a minimum of two times per week (Mondays and Fridays) by trained members of the project team. System performance monitoring and routine inspections will be conducted during each facility inspection including field kit testing for total and ferrous iron and pH of the sedimentation basin liquid and recording a round of WTS readings. Additionally, once a week, preventative maintenance and performance monitoring will be conducted by project team members including, but not limited to:

Field kit testing for total and ferrous iron and pH of the sedimentation basin at the WTS influent, RCTS effluent, sedimentation basin, and the sedimentation basin effluent.

Sediment removal from the RCTS and H-flume;

Measuring the remaining quicklime in the silo; and,

Greasing/lubing motors and bearings in the RCTS and transfer auger.

Other periodic maintenance includes, but not limited to, changing the oil motors, flushing pipelines, cleaning the flow meter and NT will be conducted monthly, semi-annually, or annually in accordance with the detailed schedule of preventative maintenance and Standard Operating Procedures (SOP) in the Water Treatment System Operations and Maintenance Manual (Weston, 2011). A copy of the Water Treatment System Operations and Maintenance Manual is included as Appendix A4-1.

4.3 Performance Testing

As previously mentioned, project team members will conduct performance monitoring twice a week for total and ferrous iron and pH of the sedimentation basin liquid and its effluent. Once a week field kit testing for total and ferrous iron and pH of the sedimentation basin at the WTS influent, RCTS effluent, sedimentation basin, and the sedimentation basin effluent will be performed by project team member. Field screening will be conducted using a Hach DR/890


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portable colorimeter and YSI 100 pH meter or equivalent. Calibration, operation, and maintenance of monitoring equipment and field screening kits will be conducted by qualified and trained employees in accordance with manufacturers instructions. Documentation of monitoring events will be recorded in the samplers logbook and/or field forms and reported weekly in the WTS summary report.

Samples may be collected for off-site laboratory analysis of total and/or dissolved metals (iron and ferrous iron), total acidity, total alkalinity, hardness, chloride and/or sulfate as requested by USACE.

Refer to the Water Treatment System Operations and Maintenance Manual (Weston, 2011) and QAPP for detailed SOPs.

4.4 Seasonal Commission of WTS

The WTS typically operates during the construction season, generally between April and November. As a result, the commissioning of the system in the spring typically includes, but is not limited to, the following:

Removing sediment from the sedimentation basin;

Installing the gravity feed lines between the TDs/HDs and the pump station;

Delivering and filling the silo with quicklime;

Starting up, re-energizing, and testing the system; and,

Performance testing the operation of the WTS including field screening multiple times a day for the first 2 days of operation and daily for the first week.

The Water Treatment System Operations and Maintenance Manual (Weston, 2011) contains SOPs for commissioning activities

4.5 Seasonal Decommissioning of WTS

Decommissioning of the WTS is typically conducted in November each year. Decommissioning generally includes, but is not limited to, the following:

Recording a final round of WTS operation readings and performance monitoring screening;

Removing and flushing the gravity feed lines between the TDs/HDs and the pump station;

Removing excess quicklime from the silo, transfer auger, and volumetric feeder;

De-energizing and draining the system piping and tanks;

Dismantling and cleaning the RCTS;

Decanting the supernatant from the sedimentation basin by opening the valves on the 6-ft and 4-ft outlets; and,

Opening the underdrain of the sedimentation basin to dewater the sediment during the shutdown period.


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5.0


GREEN AND SUSTAINABLE INITIATIVES

In addition to the green and sustainable initiatives described in the PWP the following green and sustainable initiatives have been identified for the WTS operations:

Conduct routine maintenance to allow the system to operate as efficiently as possible;

Monitor and adjust Lime feed transfer conveyor and volumetric feeder, as needed, to maintain effluent water quality and minimize overdosing (wasting Lime); and,

Reuse existing components of the WTS, to the extent practical.


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REFERENCES

Weston, 2011, Water Treatment System Operations and Maintenance Manual as prepared by Weston Solutions, Inc. for the Elizabeth Mine Superfund Site, Strafford/Thetford, Orange County, Vermont.


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Nobis Engineering, Inc. 18 Chenell Drive

Concord, New Hampshire 03301 Tel (603) 224-4182 Fax (603) 224-2507 www.nobiseng.com

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WATER TREATMENT SYSTEM TASK WORK PLAN FIGURE A2-2

2011 PROJECT SCHEDULE ELIZABETH MINE SUPERFUND SITE


ID Task Name Quantity Duration Start Finish Predecessors 1 4 7 1013161922252831 3 6 9 12151821242730 3 6 9 12151821242730 2 5 8 11141720232629 2 5 8 11141720232629 1 4 7 1013161922252831 3 6 9 12151821242730 3 6 9 12151821242730 2 5 8 11141720232629 2 5 8 1114 March 2011 April 2011 May 2011 June 2011 July 2011 August 2011 September 2011 October 2011 November 2011 December 20

Project Plans

Accident Prevention Plan

Project Work Plan

Water Treatment System Task Plan

Borrow Source Area Task Plan

WWII Infrastructure Area Task Plan

TP-1 & TP-2 Final Grading & Cover System Task Plan

QAPP

Water Treatment System Support

Cleaning out Sedimentation Basin

Commissioning Plant

Water Treatment System Operation

Water Quality Monitoring

Inspections (two times per week)

Preventative Maintenance (once a week)

Decommissioning Water Treatment System

42 days

20 days

41 days

41 days

41 days

41 days

41 days

31 days

195 days

3 days

5 days

165 days

165 days

165 days

165 days

5 days

Thu 3/17/11

Thu 3/17/11

Fri 3/18/11

Fri 3/18/11

Fri 3/18/11

Fri 3/18/11

Fri 3/18/11

Fri 4/1/11

Mon 3/14/11

Mon 3/14/11

Mon 4/4/11

Mon 4/11/11

Mon 4/11/11

Mon 4/11/11

Mon 4/11/11

Mon 12/5/11

Fri 5/13/11

Wed 4/13/11

Fri 5/13/11

Fri 5/13/11

Fri 5/13/11

Fri 5/13/11

Fri 5/13/11

Fri 5/13/11

Fri 12/9/11

Wed 3/16/11

Fri 4/8/11

Fri 11/25/11

Fri 11/25/11

Fri 11/25/11

Fri 11/25/11

Fri 12/9/11

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0%

0%

0%

0%

0%

0%

0%

0%

26 0%

27SS 0%

26 0%

26 0%

27 0%

Project: E-Mine WTS 2011 Schedule Date: April 27, 2011

Critical

Critical Split

Critical Progress

Task

Split

Task Progress

Baseline

Baseline Split

Baseline Milestone

Milestone

Summary Progress

Summary

Project Summary

External Tasks

External Milestone

Deadline

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Nobis Engineering, Inc. 18 Chenell Drive

Concord, New Hampshire 03301 Tel (603) 224-4182 Fax (603) 224-2507 www.nobiseng.com

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PROJECT MANAGER

TECHNICAL SUPPORT SITE SUPERINTENDENT SITE QC SUPERVISOR SITE SAFETY & HEALTH OFFICER

Lead Engineer

Project Engineer

Process Engineer

SITE SUPERINTENDENT FIELD SUPPORT

Regulatory Specialist

Hydrogeologist

FIELD LABOR

ELIZABETH MINE SUPERFUND SITE WATER TREATMENT SYSTEM

TASK WORK PLAN ORGANIZATION CHART


WATER TREATMENT SYSTEM TASK WORK PLAN APPENDIX A4-1

Appendix A: Water Treatment System Task Work Plan Table of ContentsLIST OF ACRONYMS1.0 PLAN IDENTIFICATION AND APPROVALS2.0 INTRODUCTION2.1 Reference Plans2.1.1 Program Work Plan 2.1.2 Accident Prevention Plan, Quality Assurance Project Plan, and Construction Quality Control Plan

2.2 History

3.0 OPERATION AND MAINTENANCE RESPONSIBILITIES4.0 DESCRIPTION, OPERATION, AND CONTROL OF FACILITY4.1 Description of Key Parts of System4.2 General Operation and Maintenance4.3 Performance Testing4.4 Seasonal Commission of WTS4.5 Seasonal Decommissioning of WTS

5.0 GREEN AND SUSTAINABLE INITIATIVESREFERENCES

FiguresFigure A2-1 - Water Treatment System Location PlanFigure A2-2 - Water Treatment System 2011 Project ScheduleFigure A4-1 - Water Treatment System Process Flow Diagram

ChartsChart A2-1 - Water Treatment System Organization Chart

Appendix A4-1

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