Biosolids are an environmentally friendly product of the water treatment process that supplies organic matter and improves soil structure and porosity to allow plants to more effectively utilize nutrients. Under the Illinois Environmental Protection Act, signed into law in 2015, biosolids were formally recognized as a safe, beneficial and renewable resource that should be used locally. Rather than being hauled miles to distant farms and landfills as in years past, the biosolids are now beneficially reused in Cook County. Air-dried biosolids look and feel like dark, fine-textured topsoil, and are used on turfgrass at golf courses, athletic fields, parks and other recreational areas, and for restoration of brownfields and other disturbed lands. To create a value-enhanced product, the MWRD partnered with the city of Chicago to co-compost woodchips from the city's routine tree trimming program and woodchips collected from ash trees lost due to the emerald ash-borer devastation to create a compost ratio of 3:1 woodchips to biosolids. The compost is produced in windrows that are maintained at a temperature of at least 131 degrees for a minimum of 15 days and are turned five times during the period as required in USEPA protocol. The active composting period is followed by four months of curing after which the product is screened through a half-inch screen to remove large pieces of woodchips and tested.