processing: Timing Just Right to Upgrade Tennessee Solid Waste Facility

Edward Umbach

The city of Knoxville, Tenn., has perfect timing. Just when it needed to modernize its transfer station and increase household hazardous waste (HHW) collection, the state offered up grants to build a permanent HHW collection center.

The transfer station site originally housed the city's incinerator and served as a garbage collection center. The city turned the site into a transfer station in 1972, and it remained virtually unchanged for several years.

Recognizing the need for modernization, Knoxville commissioned Draper Aden Associates, Blacksburg, Va., in 1995 to conduct an initial feasibility study. The consultant's waste characterization audit and cost-benefit analysis reviewed the site options among them closing the station.

The state of Tennessee also had made $500,000 grants available to build HHW collection centers in each of the state's four largest cities. Knoxville's success with its one-day, HHW collection events prompted the city to consider establishing a permanent collection center as part of its site renovation.

Historically, Knoxville's one-day, HHW collection events drew in more than 1,000 participants, many of whom exceeded their 100 pound-per-can limit. The city also was fielding hundreds of HHW phone calls each month, 30 percent of which required immediate disposal.

In 1995, the city hired the Waste Watch Center, Andover, Mass., to help determine the need for a HHW facility as well as evaluate several Knox County sites based on estimated capital and operational costs.

After reviewing the analysis, Knoxville decided to capitalize on the state's grant and begin a $2.5 million renovation of its transfer station, which would include the state's first permanent HHW collection center.

Sharing in the facility's operating expenses, Knox County signed an inter-municipal agreement, making the center regional.

Construction began in summer 1996 and was completed on schedule, on budget, in spring 1997.

The complex, which processes approximately 45,000 tons of garbage per year, contains three major facilities: the transfer station, the recycling/baling operation and the HHW collection center.

Transfer Station. The traffic pattern leading to the station was redesigned and a large queue lane was added to prevent vehicles from backing up onto city streets. The facility's entrance and exit were moved, which diverted traffic and noise from a nearby neighborhood. Landscaping also shields the site from the neighborhood's view.

A computerized scale system was added. Once the vehicle is weighed, a ticket is printed for both the customer and the city.

All waste now is discharged onto a tipping floor and pushed into new compaction pits. A new bay was added, which allows Class 3 to 4 waste to be segregated and loaded into an open-top trailer.

Recycling/Baling. A small material recovery facility (MRF) was built where materials such as cardboard are diverted and baled on-site. The building has ample storage space, and a loading dock allows the city to stockpile a significant amount of recyclables before they are marketed. A compartmentalized recycling trailer was purchased, which serves as an on-site recyclables drop-off point.

HHW Collection. The new HHW Collection Center:

* diverts reusable products;

* collects, blends and recycles latex paint;

* collects car batteries, oil and antifreeze;

* diverts selected acid and bases to wastewater treatment;

* vents aerosol containers and recycles the empty containers;

* bulks flammable materials; and

* packs miscellaneous HHW materials for shipment and disposal.

Here, individuals pull into a covered drive-though where facility staff remove HHW. Materials that are in good condition unopened containers or non-expired materials are separated and given to the public free of charge.

Materials that cannot be reused are processed by the staff. This includes testing unknown materials, diverting acids and bases, venting aerosols, bulking flammable materials, lab packing and blending paint. Latex-based paint is sent to a local firm to be remanufactured for city use.

After processing, materials are placed into 55-gallon drums, which are stored in one of two pre-fabricated units, each with electronic monitoring and security, fire suppression systems and drainage/spill containment systems. The materials are stored until sufficient quantities can be collected.

During the first month, more than 400 customers brought about 1,000 gallons of HHW. A chemist and technician operate the collection center, which is open Tuesday through Saturday.

The center also includes an employee break room, the transfer station foreman's and HHW supervisor's office space, as well as an education room. Additionally, storage space was added and a larger scalehouse was constructed.

The facility was designed to blend in with the area's commercial architecture. All site areas were paved or landscaped to mitigate dust and dirt. And, since the facility's opening, additional counties have indicated an interest in becoming partners with the city.

Agreements Verner, Liipfert, Bernhard, McPherson & Hand have chosen Gershman, Brickner & Bratton Inc., Fairfax, Va., to conduct an analysis of the city of Alexandria's and Arlington County's (Va.) waste-to-energy facility.

American Disposal Services Inc., Burr Ridge, Ill., has signed a definitive agreement to acquire Chicago Disposal Inc., adding approximately $24 million to the company's revenue.

Award Annapolis-based Maryland Environmental Service and Baltimore, Harford and Montgomery Counties have been selected as recipients of the 1998 Maryland Recyclers Coalition Award for the Best Market Development Program.