The ultimate recycling project is underway at the city's wastewater treatment plant, where the bags of leaves and piles of branches picked up during the City of Delta's fall cleanup campaign are combined with biosolids to create compost.
Andy Mitchell, chief wastewater plant operator, said the organic matter from the plant is tested to prove volatile solids reduction has occurred through the use of mechanical and biological methods. The resulting sludge is then combined with the leaves and chipped branches, mixed with a tractor to incorporate air and piled into windrows (pictured in the background). A combination of heat, moisture and oxygen kills off any remaining pathogens. After ensuring compliance with applicable state and federal regulations, the city applies the compost to city-owned fields adjacent to the wastewater treatment plant in North Delta. The fields are leased to a rancher for grazing purposes. "The compost grows great grass and the cows seem to love it," Mitchell said.
The process is highly regulated, he added. One of the site restrictions limits on-site compost storage to two years, so the compost is applied to the fields regularly.
Fall cleanup is conducted by city crews with the assistance of a Delta Correctional Center work crew under the supervision of Lester Severson.
"The compost is going to good use," said Steve Glammeyer, utilities/public works director. The other alternative is transporting the leaves and branches to the county landfill, where they'd be buried, incurring tipping fees for the city, unnecessarily taking up space and cutting into the life of the landfill.