Heat-Dried Biosolids Pellets

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 around the country. 

In the New England region, there are two wastewater treatment facilities that have their biosolids heat-dried into a product similar to Milorganite:  the Massachusetts Water Resources Authority (MWRA) Deer Island Wastewater Treatment Plant 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 ("Econo Gro") is distributed throughout the country by NEFCO and, in New England, by New England Organics.  Bagged product from the MWRA facility is distributed to local MWRA member communities under the Bay State Fertilizer label.

Uses of Heat-Dried Biosolids Pellets in the North East

General

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
• shrubs
• fruit trees
• agricultural crops (e.g. corn, other grains)
• greenhouse potting mixes

Like all biosolids, composts, and animal manures, they 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 keep feeding plants steadily throughout the growing season.  Biosolids pellets usually provide 4 - 6% N, 2% P, and <1% K. 

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.

This video (June 2009) provides details about how the NEFCO heat-dried biosolids pellets are one component in the carefully controlled process of growing turf grass in central Rhode Island.