Bay View Treatment Plant Integrated Improvement Programme, Toledo, OH, USA

Work on the two key elements in the programme of improvement at the Bay View wastewater treatment plant – one of largest in northwest Ohio – is progressing well towards scheduled completion at the end of 2006.

Forming a major component of the Toledo Waterways Initiative - the city’s 15-year scheme to improve its ageing facilities – the scheme comprises the provision of a new 227,000m³ equalisation basin and additional wet weather capacity.

The new equalisation facility is a cast-in-place concrete structure, formed as two cells. The project also involves the construction of a new dewatering pump station and electrical building together with the installation of pumps, controls and other associated equipment.

In addition to the increased treatment capacity, the work at Bay View also includes the construction of a new pump station, odour control system and preliminary treatment facility.

The overall scheme also calls for an extensive programme of work to improve sewers in many areas, the disconnection of downspouts and drains flowing directly into the sanitary sewer lines and the adoption of a Long Term Control Plan to reduce combined sewer overflows.

This part of the project will require associated new sewer/force mains to be installed, a number of new pump stations to be built and some of the existing overflow pump stations to be decommissioned and demolished.

Black and Veatch were awarded the programme management contract, worth US$35 million in November 2002 and work has already been completed on a number of the other upgrade and renovation components of the $450 million wider initiative.

TOLEDO WATERWAYS INITIATIVE BACKGROUND

The Toledo Waterways Initiative arose to solve a long-standing problem of contamination of the area's three major watercourses – Swan Creek and the Ottawa and Maumee Rivers.

Although sanitary and storm sewers have been constructed as independent systems since the 1950s, around a quarter of the city is still served by the old-style combined connections. At times of heavy rain, the excess flow in these combined sewers can overload the wastewater infrastructure, leading to the storm-water/raw sewage mix backing up into homes or over-flowing into waterways.

The resulting pollution caused by these discharges ultimately led to the commencement of legal proceedings against the city by the US Federal and Ohio State Environmental Protection Agencies (EPAs).

The situation was resolved in July 2002, with overwhelming public approval for a proposal to upgrade the sewer and wastewater treatment facilities and thus settle what was, by then, an 11-year old lawsuit.

Although this meant that consumers would face incremental rises in their sewer charges over the project's 15 year duration, detailed analysis of the overall state of the sewer system had revealed that nearly half of the existing lines were in either a poor or critical condition.

However, to reduce the impact on residents, the city authorities are also actively pursuing other possible avenues, including direct funding and grants – such as the one received in 2005 from the US EPA for the equalisation basin project.

WASTEWATER TREATMENT FACILITIES AND SEWERAGE SYSTEM

In November 1922, Bay View was intended simply as a pump station to provide centralised discharge, but prior to completion, its role was extended to include treatment by order of the Ohio Health Department. The plant's primary treatment facility came into service in June 1932 and has been modified and upgraded many times over subsequent years.

Today, treatment comprises screening, grit removal, pre-aeration, swirl concentration, primary clarification and aeration followed by conventional secondary treatments and step-aeration activated sludge processes. Effluent discharge is to the Maumee River.

Sludge treatment comprises gravity-thickening for primary sludge, dissolved air flotation of the waste-activated sludge and digestion of the thickened primary and waste-activated sludges. After the digested sludge has been dewatered by belt filter process, it is transferred off-site for beneficial agricultural use.

The provision of the new equalisation basin and enhanced wet weather treatment capacity is intended to help remove the need to discharge untreated wastewater into the Maumee River during heavy rains.

The equalisation basin will hold peak wastewater flows which exceed the plant’s capacity – itself being extended to cope with up to 600,000m³/day of combined raw sewage during storm periods – until the immediate demand is reduced sufficiently to allow it to be treated.

The size of these facilities means that they could not both be accommodated within the existing works boundary, leading to the consideration of two sites adjacent to the plant as potential locations for the equalisation basin.

After due consideration of the economics and practicalities, the decision was made to build on a portion of the City-owned, 12-hole, Bay View Retirees Golf Course; three holes would be lost, leaving a standard nine-hole course. This selection not only saved the city around $10 million in acquisition and construction costs, but also spared sewer customers significantly higher bills.

The design phase concluded in September 2004, with construction beginning in June the following year. Work is progressing well, with the wet weather facilities due to be completed in the autumn of 2006 followed by the first phase of the equalisation basin by December.

SEWER UPGRADES

The programme also comprises a series of sewer upgrades to compliment the work at the WWTP. As part of the project, over 8km of new sewer / force main has been installed around Point Place, two new pump stations built and the three existing sanitary sewer overflow pump stations demolished. The work was undertaken in three phases, beginning in September 2003 and concluding in the late spring of 2006.

Another large, three-phase sewer improvement project is currently being implemented in the River Road area of the city. Construction began in 2005 and will close with the scheduled completion of phase 3B in 2010.

In addition, the ongoing evaluation of the sanitary and storm sewer system has recently been rolled out to the Bennett area of the city. Fieldwork began in February 2006 and it will continue to the end of the year, with a final report to be submitted in March 2007.

LONG-TERM CONTROL PLAN

The final – and arguably the most important – component of the project involves the adoption of a Long Term Control Plan. Required as part of the necessary Consent Decree, this sets out the improvements that are proposed to address the city's particular problems, ensure that federal and state water quality standards are met and improve water quality for recreation and aquatic life.

In mid-December 2005, the City of Toledo sent its plan to the Ohio and US Environmental Protection Agencies for approval.

KEY PLAYERS

The City of Toledo own and operate the facilities; they awarded the programme management contract for the water initiative project to Black and Veatch.

The project employs a number of engineering, construction and project management sub-contractors, including Arcadis FPS, Brigette's & Associates Inc, the Mannik & Smith Group, Ribway Engineering Group, G. Stephens Inc, and Polytech. Capacity Building, a collaboration between the City of Toledo, the University of Toledo and the Associate General Contractors of Northwest Ohio are involved in the construction.

ERC provide financial consulting services, CSO Technik is supplying the Vacflush storm tank cleaning system; testing services are by TolTest. Other subcontractors involved include Mijan Designs Inc, SSOE, Water Resources Strategy, Woodlands Consulting Group, Tucker Young Jackson Tull, Funk Luetke Skunda, Limno Tech, Tetra Tech, Hull & Associates and Vision Mechanical.