Compost operation keeps track with mosaic mapboard

The Camden County Municipal Utilities Authority, N.J., operates the Delaware No. 1 wastewater plant, one of many treatment facilities composting sludge to eliminate off-site disposal costs. Selling the nutrient-rich compost has become an economic alternative to landfills and incineration.

The county’s composting venture will ultimately help protect taxpayers from increased water and sewage costs by containing sludge disposal costs, according to Michael Holmes, assistant chief of sewage plant operations.

The 80-mgd treatment plant opened its composting facility earlier this year. The 20-tunnel, in-vessel system, designed to handle 50 dry tons of sludge per day, uses a unique German process that mixes sludge cake, recycled compost and amendment (sawdust) in large horizontal tunnels to produce two marketable products: Soil-Fix and Sure Grow. This continuous process, the largest in the United States using horizontal tunnel compression and curing, is carefully monitored by a modular mosaic interface located in the facility’s control center.

In the control center, three workstations and the mosaic panel give operators up-to-the-minute status on the entire composting system. The mosaic mapboard consists of individual square tiles, each painted with a portion of the system graphic. Tiles are aligned and snapped into a metal grid to form a seamless, high-resolution mapboard surface. The tiles’ unique, modular design allows integration of instrumentation, push-buttons and LEDs into the panel.

Systems analyst David Carey says, “In one glance, operators can check sludge and wood chips levels before the composting process starts, determine mixing status and then see the route to a composting tunnel.”

Mosaic’s ability to mimic a process system using high-resolution graphics allows Camden County operators to control and monitor activity of conveyors, blowers, vacuums, tunnels reactors and mixing bin equipment. According to Matthew Jacovelli, supervisor of sludge operations, the board’s enhanced graphics orient operators with any area on the board. Process control software, controlled by the operators, drives illumination of the board’s LEDs.

“Operators following the board’s black line diagram are instantly aware of which in-feed and out-feed conveyors are running and to which of the 20 tunnels or four reactors they are traveling,” Jacovelli says. “If an LED on the tiles is lit, all operators immediately know which conveyor is activated. A CRT also provides that detail but on a much smaller scale. Mosaic mapboards offer the big picture.”

Unlike sheetmetal mapboard surfaces, which lose their visual integrity when modified, mosaic mapboards can be changed by simply removing a tile from its position and snapping a new one in its place.

Camden County recently saw the fruits of the system’s efforts when it sold the first batches of compost to a local racetrack and botanical garden. Product demand has been high from nurseries, landscaping and top soil dealers.