On the day of its commissioning in February 2010 — even before it had treated its first gallon of wastewater — the McComb (Miss.) Regional Wastewater Treatment Facility was already being hailed as a huge success.
The $34-million facility was paid for almost in its entirety through a loan from the Mississippi Department of Environmental Quality's Water Pollution Control Revolving Loan Fund. The plant was completed approximately $1 million under budget and nearly three months ahead of schedule. And at the groundbreaking nearly two years before, the mayor of McComb had proclaimed the facility would be "the most advanced, most energy-efficient, and most cost-efficient wastewater treatment facility in the state of Mississippi."
There's plenty of credit to go around for the project: a forward thinking City of McComb administration; an innovative facility design and development plan from Jackson, Miss.-based Neel-Schaffer Inc.; and the skilled workmanship of Mandeville, La.-based Max Foote Construction Company Inc.
Public-private partnership also a key to plant's success
Credit is also due the company managing the new treatment plant. In 2009, as construction neared completion, the city contracted with a public-private partner — Severn Trent Services — for the transition, commissioning, ongoing operations and maintenance of the facility. For the next six months, the company's technical staff worked with the City's engineer and Max Foote Construction during the final stages of construction of the facility and then began managing the commissioned plant in February 2010.
The result? A year later, the treatment plant was named the Best Regional Wastewater Treatment Plant by the Mississippi Municipal League. The honor recognized the facility's "exemplary management and visionary leadership which helped keep multiple contractors, subcontractors, inspectors, and vendors on time and under...budget."
State-of-the-art biological reactor
The McComb facility features a state-of-the-art vertical loop reactor (VLR) process with a Cannibal® interchange biological reactor (IBR), the first of its kind in Mississippi and one of only 12 systems in the United States. A version of the activated sludge process, the VLR system provides a greater degree of water pollutant removal. In addition, the IBR process significantly reduces waste activated sludge, unlike the conventional activated sludge process which produces a large volume of biosolids that must be disposed of by land application or in sanitary landfills.
The treatment plant is designed to produce a maximum daily flow of 15 MGD. Permitted for a maximum daily average flow of 5 MGD, it has produced a daily average of 2.5 to 3 MGD. From February 2010 to August 2011, the facility treated approximately 1.5 billion gallons of wastewater.
The new plant replaced a lagoon treatment system, which was removed from service and now functions as a flow equalization basin and regional pumping station. West McComb influent is delivered to the facility by a pump station with two low flow and two high flow submersible pumps. Flow from East McComb is transmitted by a series of lift stations and a gravity flow collection system.
Increasing plant efficiency and reducing costs
In addition to overseeing operations, Severn Trent Services has effectively implemented efficient process control measures at the facility. In March 2010, the company installed the water information management system (WIMS). A comprehensive process control software, the WIMS database collects information from operators and laboratory technicians to determine the proper control parameters for efficient operations. Numerous human interface procedures are constantly monitored and verified by both field and laboratory analytical tools to maintain peak process performance. Monthly operation reports are generated after all laboratory data are input into the database. Once the reports are generated, NPDES discharge monitoring reports are produced.
Severn Trent Services employees closely monitor the dissolved oxygen, pH, temperatures and oxygen reduction potential readings at various points through the VLR. The data are recorded daily and input in the WIMS system. Dissolved oxygen, pH and temperature of the influent and effluent are also measured daily, enabling plant staff to respond to issues quickly and make any necessary changes to maintain operational efficiency and permit compliance.
An in-house lab staffed by Severn Trent Services performs daily chemical analyses which results in considerable cost savings compared to contract laboratory costs. The lab conducts analyses on BOD, COD, TSS, VSS, pH, ammonia nitrogen, alkalinity, settleable solids and fecal coliform.
The plant's staff also produced cost efficiencies through ongoing plant maintenance practices. The McComb plant's annual maintenance budget is $30,000, with any funds remaining at the end of the contract year being rebated to the City. In August 2011, Severn Trent Services presented a rebate check of $3,179.40 to the City representing savings achieved in the previous fiscal year.
Regulatory compliance and emergency response
The NPDES established new BOD and ammonia nitrogen discharge limits of 7.3 mg/l BOD and 1.46 mg/l ammonia nitrogen to be in compliance by January 1, 2011. The plant achieved compliance by May 31, 2010, seven months prior to the mandatory date. Staff also increased the average percentage of major pollutant removal from the regulatory compliance limit of 85 percent to 98.5 percent.
Emergency response is a top priority for plant staff. During heavy rainfall events, when many systems experience higher flows due to inflow and infiltration, the staff implements procedures to divert flow. When storms arise, the plant enters into "storm mode" in which plant personnel report to the facility and divert the influent to the third reactor cell, thus protecting the aerobic process in aeration basins #1 and #2.
In the event of major emergencies, Severn Trent Services forms teams from other projects in order to respond to and resolve crisis situations at any of the plants it manages. For example, when Hurricane Katrina ravaged the Gulf Coast in 2005, the company's regional staff was augmented by its Technical Services Group and spent weeks living in tents and assisting with operations at facilities it managed throughout the recovery process.
Accomplishments
In its first annual report of the new plant's operation, Severn Trent Services cited the following accomplishments:
- Implementing a policy that provided septic haulers clear direction on the proper disposal of waste products, thereby significantly reducing waste disposal in the collection system while providing additional income to the City.
- Maintaining lab certification through successful completion of the Discharge Monitoring Report-Quality Assurance studies.
- Eliminating waste sludge production in the first 14 months of plant operations by using the sludge Cannibal system.
- Commissioning its Technical Services Group to provide a site energy management plan to the City. Recently completed, the plan suggests possible cost savings measures at the plant — savings that at other plants have totaled as much as several hundred thousand dollars per year.
According to Stan Wright, senior area manager for Severn Trent Services, "Our operating services group is doing for the McComb Regional Wastewater Treatment facility what we are doing for approximately 400 water and wastewater treatment facilities in the United States: reducing costs, increasing operational efficiency and ensuring regulatory compliance. And we and our partners — the City of McComb, Neel-Schaffer and Max Foote Construction — take great pride in being named the Best Regional Wastewater Treatment Plant in Mississippi."
For more information, e-mail info@severntrentservices.com.
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