Town of Pound Wastewater Treatment Plant Upgrades and I-I Projects

The Pound Wastewater Treatment Plant (WWTP) was originally built in the mid-1970s as a 0.3 million gallons per day (MGD) plant. The construction of the Red Onion Correctional Center in the mid 1990’s necessitated an upgrade/expansion of the WWTP to 0.5 MGD. In the 20+ years following this upgrade, the WWTP is now in need of a major rehabilitation to address aging equipment and mitigation of excessive inflow and infiltration (I/I) in the sanitary sewer system.

T&L is partnering with the Town in the planning, design, permitting, bidding and construction of the WWTP rehabilitation and I/I mitigation project which includes rehabilitation of the WWTP including a new flow equalization basin.

T&L assisted the Town of Pound in obtaining funding through the Virginia Department of Environmental Quality in the amount of $3.38 Million for rehabilitation of the WWTP. Of this total, $1.8 Million is in the form of principal forgiveness (grant) with the remaining $1.58 Million as a zero-interest loan for 25 years.

The proposed construction budget is $2.38 Million.

Additionally, T&L and Tri-State Utilities have been working with the Town of Pound on their old, aging and leaking collection system.

A sampling of our services have included:

• Development of a PER for removal of I/I
• Six (6) months of flow monitoring utilizing three (3) of T&L’s in-house flow meters
• High performance jet cleaning of the sewer system to facilitate CCTV inspections
• CCTV inspection of the sewer system for approximately 2.5 miles
• Inspection of 130 manholes
• Assessment of the findings and recommended solutions including line replacement and CIP lining
• Development of a detailed report including videos, findings, cost estimates, etc…
• Work with funding agencies such as DEQ, RD and others for funding of the project for I/I removal

Photos

Tazewell County PSA Claypool Hill WWTP

The Tazewell County PSA engaged T&L in March 2012 to update the Preliminary Engineering Report (PER) to address a stringent VPDES limit for ammonia which was imposed on the TCPSA by the Department of Environmental Quality (DEQ). The PER recommended an upgrade and expansion of the existing WWTP from 0.35 MGD to 0.75 MGD capacity address the stringent ammonia discharge limit and meet the future needs of the Claypool Hill and Wardell service areas.

Project Funding: T&L provided assistance to the TCPSA in securing the project funding with included multiple funding agencies, each with differing requirements. Funding agencies included:

DEQ/RLF (LOAN) $8,255,550
DEQ/RLF (GRANT) $1,000,000
SWVA W/WW $400,000
LOCAL $252,520
TOTAL $9,908,070

In July 2012, T&L began final design phase services for the upgrade and expansion of the WWTP. Construction was completed in October 2015 at a cost of $5.7 million, which was approximately $1.0 Million under T&L’s engineering estimate of $6.7 Million and 1.6% above the award amount. One important step taken by T&L, which was a big factor in the success of the project, was the use of a pre-qualification process prior to the formal bidding process. This provided the TCPSA with reasonable assurance of a pool of bidders with the experience and capacity to undertake a specialized wastewater treatment plant.

The entire project was completed $1,535,019.21 under the TCPSA’s budget.

Claypool Hill WWTP I&I Study

T&L performed an analysis of sanitary sewer flows in support of the Tazewell County Public Service Authorityís Claypool Hill Wastewater Treatment Facility upgrade and expansion project. The analysis was performed to determine whether or not excessive inflow and infiltration was present in the collection system in order to satisfy Virginia Clean Water Revolving Loan Fund requirements.

Wastewater treatment plant influent flow records were utilized to convert flows seen at the wastewater plant to a per capita basis based on the total equivalent population of plantís service area. The conversion of the flow to a total equivalent population basis of gallons per capita per day was important to account for the relatively large contribution of commercial users in the service area.

Running seven day flow averages, as well as flow data from each day over an eleven month period, were compared to precipitation records and water use records to examine for any potentially excessive inflow and infiltration as defined in the Virginia Clean Water Revolving Loan Fund guidelines, Section 8. Although there were a few periods which would be defined as having excessive flow days, T&L was able to demonstrate that these problematic flows were corrected by the efforts of the Tazewell County Public Service Authority. T&L was able to demonstrate to the satisfaction of DEQ that excessive inflow and infiltration was not present in the sanitary sewer collection system.

Photos

Giles County PSA Water System

Giles County PSA Water System

For many years, the citizens of Giles County were in need of a reliable public water system. The only public water supplies were located in the Towns; Glen Lyn, Rich Creek, Narrows, Pearisburg, and Pembroke. A regional project was undertaken over the course of many years. The goal of the regionalization project was to construct a water treatment plant and interconnect the towns to create a regional water distribution and treatment system.

T&L assisted the Giles County PSA in this endeavor in the following ways:

• Assistance to the PSA in the negotiation of inter-municipal agreements with each participating locality; and
• Working with the PSA to find a new source of water for the PSA and participating localities;

A groundwater well near the New River was able to produce up to 2.0 MGD of raw water of adequate quality with microfiltration treatment. Pilot studies were performed and the microfiltration system was designed, constructed, and placed into service with a design flow of 2.0 MGD.

T&L also developed hydraulic models for the interconnection of the towns to create a regional system for Giles County. Several pressure zones were required to maintain proper pressures throughout the system, necessitating the construction of pump stations and tanks to serve these zones.

Recent studies have been undertaken by the PSA with T&L’s assistance to develop alternate sources of water. One source studied is raw water to be withdrawn from the New River, and a second is a potential mine water source.

Photos

City of Waynesboro Sewer Projects

City of Waynesboro Sewer Projects

The City of Waynesboro (City) owns and operates a sewage collection and treatment system which includes:

• Approximately 120 miles of sanitary sewer mains;
• 2,800 manholes;
• 8 sewer pump stations; and
• A Wastewater Treatment Plant (WWTP).

The City’s system has experienced excessive I/I and WWTP bypasses. The City and T&L have partnered together over the past decade to develop new plans for the reduction of I/I within the City’s sewage collection system.

A sampling of T&L’s ongoing services include:

• Updating the existing sewer system model to account for I/I work completed;
• System flow monitoring over a seven-month period to determine base, average wet weather and peak flows;
• Evaluation of the overall system to account for completed projects and updated flow information;
• Identification/prioritization of 19 I/I projects to assist the City with I/I issues; and
• Development of detailed costs and a five-year Capital Improvements Plan (CIP) for the identified projects.

In accordance with the five-year CIP, T&L provided preliminary engineering, survey, design, and construction services required to complete ten (10) of the identified projects. In addition to the aforementioned project services, the City and T&L have collected pre and post project flows from flow meters strategically placed downstream of each project.

To date, the City has completed ten (10) of the projects which have consisted of:
In-Situ Lining of 18-inch Sewer – 915 LF
In-Situ Lining of 12-inch Sewer – 6,855 LF
In-Situ Lining of 10-inch Sewer – 6,545 LF
In-Situ Lining of 8-inch Sewer – 21,709 LF
In-Situ Lining of 6-inch Siphon – 2,730 LF
Sewer Point Repair – 1,060 LF
Manhole Rehabilitation – 1,611 VF
Sewer Line Replacement – 20,085 LF

Since 2009, construction costs have totaled approximately $4.3 Million, which is significantly under T&L’s engineering estimates.

Photos

City of Norton – Upper Norton Dam and Spillway Improvements

City of Norton – Upper Norton Dam and Spillway Improvements

The City of Norton owns and operates two impoundments for water supply purposes, one situated above the other on Benges Branch, to the south and above the downtown area. The upper dam was completed in 1959 and modified in 1997. The reservoir is a 73 foot deep earthen structure with a maximum capacity of 202 acre-feet. Regulations require that the reservoir be capable of safely passing the Probable Maximum Flood (PMF). The City of Norton partnered with T&L to plan, design, permit and construct improvements to the Upper Norton Dam and spillway.

A summary of T&L’s services includes:

• Preparation of a Preliminary Engineering Report (PER) to evaluate alternative solutions for improvements to the existing impoundment;
• Evaluation of the existing spillway capacity;

The PER recommended that an auxiliary spillway be constructed to increase capacity for passage of the PMF. To retain the same pool elevation and provide an adequate channel for the spillway, a labyrinth spillway (shaped like a “zigzag”) was utilized due to space considerations.

Major design and construction elements included:

• A 50-foot wide reinforced concrete auxiliary spillway chute with energy dissipation at the outlet;
• Structural concrete chute walls to contain spillway flows; and
• A labyrinth weir at the inlet of the spillway.

This project was completed in 2013, with a construction cost of approximately $2,232,000.

Photos