One common form of Class A biosolids product is made by drying dewatered wastewater solids with heat. Milorganite is a long-standing product made in this way. Milorganite has been in use since the 1920s and is a favorite for golf course maintenance. It is sold in bags in hardware stores and garden centers around the country.
In New England, there are two water resource recovery facilities (WRRFs) that have their biosolids heat-dried into a product similar to Milorganite: the Massachusetts Water Resources Authority (MWRA) in Boston and the Greater Lawrence Sanitary District (GLSD) in North Andover, MA. At both facilities, the heat-drying, fertilizer-production operations are conducted by New England Fertilizer Company (NEFCO), and bulk product is distributed throughout the country by NEFCO and, in New England, by various marketers. Bagged product from the MWRA facility is distributed to local MWRA member communities under the "Bay State Fertilizer" label. In Quebec, the community of Laval makes a pelletized biosolids product.
Uses of Heat-Dried Biosolids Pellets in the North East
Bay State Fertilizer, Milorganite, and other heat-dried biosolids pellets can be used in a wide variety of applications:
- grass planting or fertilizing (top-dressed)
- home gardens
- fruit trees
- agricultural crops (e.g. corn, other grains)
- greenhouse potting mixes
Like all biosolids, composts, and animal manures, these fertilizer pellets provide slow-release nutrients, meaning that it takes microbial activity in the soil to release the soluble forms of nitrogen (N), phosphorus (P), and potassium (K) that plants can absorb. This means that one application will feed plants steadily throughout the growing season.
Use of Heat-Dried Biosolids Pellets in Turf Grass (Sod) Production
Because it is a regionally-produced, recycled product delivered in bulk, the recycled NEFCO biosolids from MWRA and GLSD provides nutrients to larger agricultural operations at lower cost than traditional synthetic chemical fertilizers. Turf farmers - those who produce roll-out sod for rapid landscape restoration at construction sites and around homes - use this fertilizer because of its slow release quality and the fact that it also adds micronutrients and organic matter that help restore and build the soil.
See: Heat-dried Pellets For Turf (below).