Tracking the Trash

Avatar Partners' RFID solution adds efficiency
and accuracy to Allied Waste's disposal services  

By Michael Chee

Most of us don't think about waste beyond the local trash trucks that pick up our bins once a week. However, waste collection is just the start of a long process that can stretch across many days and hundreds of miles.

As local landfills have reached their capacity, many municipalities have contracted with waste disposal companies to collect, consolidate, recycle, and transport their solid waste to remote areas for its eventual disposal.

At over $6 billion dollars in income, Allied Waste is the second largest waste disposal company in the U.S., employing 25,000 workers to service its 10,000,000 customers. Allied Waste operates collection facilities, transfer stations, rail centers, and landfills across the country.

Like many large companies, Allied Waste owns, leases, or is responsible for many valuable assets that must be tracked and traced individually and in concert with other assets and systems. The operation of those same assets across multiple working environments with total integration into an intermodal rail system requires a system that integrates with multiple logistical and operational applications.

Allied Waste collects the waste from the individual trash trucks at a transfer station where it is sorted for recycling and consolidated into large containers for transport to landfills. These containers are filled and trucked to rail centers for shipment to the landfill where they are unloaded onto other trucks and brought to the location where the trash is disposed. The efficient utilization of these containers requires that their whereabouts are constantly known so that accurate forecasts are available to accommodate variable workloads and allow for new sales.

Avatar Partners (www.avatarpartners.com) was hired to review Allied Waste's requirements, develop specifications, research solutions, and provide an assessment of the best solutions. After analyzing the current operations, several critical needs arose. The solution would have to integrate with legacy ERP and logistical systems, be robust enough to work in the waste environment, support highly accurate data input methodologies, allow seamless forecasting, and ease the complicated rail reconciliation process.

Avatar Partners reviewed multiple RFID and optical systems, including passive and semi-passive tags, two dimensional optical tags, and optical character recognition (OCR) systems. OCR has improved substantially over the past several years; the technology can now provide 95%-98% accuracy when working with known identification markings (if it can get a clear view). Its tag cost for this project would have been minimal since shipping containers must have an identification number stenciled on their sides already. However, the camera cost and software cost along with a maximum 98% accuracy made it prohibitive for this application. While 2D optical tags were an improvement, the same issues with getting a clear view that filled a significant portion of the frame in this difficult work environment precluded the level of accuracy and reliability that was required.

The orange container is mounted on a chassis being driven over a set of scales. The empty and loaded containers are driven over the scales to determine the amount of waste that will be deposited in the landfill.

After much analysis, Avatar Partners concluded that of all asset-tracking technologies, only RFID was flexible enough to allow for accurate reads from fixed and mobile readers, in all weather, from a variety of distances and angles to meet Allied Waste's needs. While semi-passive tags offered greater range, passive tags were shown to be sufficient while being less costly and having a longer life span.

Avatar Partners then worked with Allied Waste to refine the nature of the problem by examining the parent/child relationship between the containers and their transport vehicles as they moved through the entire process. "We were able to define that with only a few changes, by tagging the transport vehicles instead of the containers, we could successfully track each container throughout the process, " says Deon Colchester, Senior Engineer at Avatar Partners. "This reduced the number of required tags from tens of thousands to several thousand. "

The latest passive RFID tags allow for sufficient read range while reducing the problem of reading the tags on nearby transport vehicles. Passive tags allow for a dual mode reader that would read both vehicle and railcar tags, further reducing complexity and cost. Dual mode readers mounted on the "top pick" lifts that are used for automatic reads while loading and unloading the containers from both the railcars and different over the road chassis.

The readers on the top pick fork lifts and integrates touch screen displays, which allow the drivers to select the container and marry them to a truck chassis at the start of the process.

Since the weight of each load is measured at both ends of the process and the associated containers and driver information is recorded, readers located at the entrance and exit truck scales will allow the container and chassis ID information to be married to the container, driver, and other load information. This solution would cement the parent-child relationship between container and chassis and weight ticket.

The orange container is mounted on a loading chassis at the Staten Island Transfer Station, backed up to a compactor that is out of view. The compactor will ram the container full of waste collected from Staten Island homes and businesses. About 100 yards from this entrance is a rail spur where the containers will be loaded onto railcars for shipment to the landfill.

A "top pick loader" (which picks up the containers from the top unlike a fork pick that picks up containers from the bottom) is equipped with a dual mode RFID reader to read both the railcar tags and the tags on the truck chassis. Each top pick loader has a touch screen device that is wirelessly connected to the main database. Each railcar and container is displayed in sequence on this display. The container is easily selected from the screen for loading or offloading and then married to the adjacent railcar or truck chassis as captured from the RFID reader, after which it will automatically update the database. They record which car the container is on and which position it is in on the railcar. Depending on the type of container and type of railcar, there can be anywhere from two to 12 containers per railcar.

Railcar tag readers at the beginning of the rail spur automatically update the system as to the railcar order as the cars enter of exit the spur. This gives operations a graphic description as to the relationship of each container and its associated railcar. This allows the top pick loader to easily select the correct container as it is off loaded from the railcar and placed on a RFID tagged chassis.

This system is projected to allow Allied Waste to save over $1 million and increase availability of resources for new sales. "Avatar Partners has taken a very thorough and detailed approach to the design of Allied Waste unique software solution. We are very pleased with the process, " says Matthew Henry, General Manager at Allied Waste.