Introducing Biosolids

September 29, 2015

Today’s Guest Article is by Ned Beecher, Executive Director of the North East Biosolids & Residuals Association.

Management of wastewater solids is a continual challenge for wastewater treatment facilities, representing anywhere from 15 to 50 percent of operating costs. At the same time, there is growing recognition of the resources in biosolids, especially nutrients, organic matter, and energy – the recovery of which can lower net costs for biosolids management. Leading wastewater professional groups are emphasizing “resource recovery” from wastewater and biosolids.

For example, the Water Environment Federation emphasized in a 2011 policy statement that it “supports a comprehensive approach to wastewater treatment and solids management that ensures the recycling and recovery of valuable resources including water, nutrients, organic matter, and energy. In addition, WEF recognizes that biosolids, natural byproducts of the wastewater treatment process, are a renewable resource that is too valuable to waste….”

What happens with biosolids in this region?  Connecticut and Rhode Island incinerate most of the solids produced at their wastewater treatment facilities, while a diversity of disposal and beneficial uses are the norm in the three northern New England states and many parts of the Mid-Atlantic.  For example, Maine has long led the region in recycling wastewater solids: in 2011, 74% of the state’s 29,900 dry U.S. tons were recycled, with 26 percent landfilled.  In those states with large areas of farmland, such as upstate and western New York and Pennsylvania, use of biosolids on farms is also common, although much biosolids is still landfilled. 

More densely populated regions, such as New Jersey and urban New York, rely on outlets farther away from their wastewater treatment facilities, including landfills, incinerators, and farm and land reclamation sites.  However, most recently, several northeastern cities are researching urban and suburban uses of highly treated, Class A biosolids products, so as to reduce transportation needs and put the nutrients and organic matter in biosolids to use more locally.

Massachusetts provides an in-between example of recent biosolids use and disposal practices and trends:

• First, as in many places, the total mass of solids produced in the state has risen slowly but steadily over time.  The total mass of solids managed in Massachusetts increased from an estimated 153,300 dry U.S. tons in 2005 to 201,700 dry U.S. tons in 2011.
• As total production increased, the percentage beneficially used through application to soils – almost all of which is Class A EQ (Type 1) compost and heat-dried pellets (from MWRA/Boston and Greater Lawrence Sanitary District) – increased slightly, from 35 to 36 percent. Much of this Class A EQ product is used on turf farms, in agriculture to grow corn and hay crops for animal feed, for land reclamation (i.e. creating new topsoil on gravel pits), and in landscaping (e.g. parks, sports fields). 
• The percentage incinerated (e.g. Upper Blackstone/Worcester) decreased from 38 to 36 percent during the same period, and this decline has continued since 2011, with the Fitchburg incinerator closing, in part due to new, stricter EPA air emissions requirements. The amount of solids combusted in Massachusetts in 2011 included about 3 percent of heat-dried pellets from MWRA/Boston that was used as an alternative fuel in cement kilns – a relatively new use.
• Landfill disposal of wastewater solids has also decreased slightly in recent years, from 27 percent in 2005 to 25 percent in 2011. 
• Now, with the new ban on landfilling of food scraps coming into effect in Massachusetts, the markets for processing organic residuals in general – biosolids and food scraps included – are changing.  For example, both MWRA/Boston and Greater Lawrence have considered taking in food scraps for co-digestion with their biosolids.  Interest in digestion is booming in this region and across the continent, as it becomes widely recognized as an alternative, green fuel for production of electricity and heat.  Some wastewater solids incinerators, such as the Synagro facility in New Haven, CT, are also capturing energy from the combustion process and generating electricity.

Wastewater exists – and its volume increases with the population.  So wastewater solids must always be managed, 24-7, 365 days a year.  Our region’s wastewater treatment facilities keep pace, finding safe, cost-effective, and environmentally sound ways to manage solids.  And the steadily growing trend is to recycle biosolids, putting to work the nutrients and organic matter they contain and reducing the negative impacts that this organic material can have in landfills.

By Ned Beecher

NEBRA is a non-profit professional association advancing the environmentally sound and publicly supported recycling of biosolids and other organic residuals in New England, New York, and eastern Canada. Visit NEBRA’s website to find out more about biosolids, including many references, links, & the science.

And coming up October 19^th is the Northeast Residuals & Biosolids Symposium, the annual regional biosolids conference sponsored by NEBRA and the New England Water Environment Association.  This year, the conference is in association with BioCycle’s REFOR15 conference.

NERC welcomes Guest Blog submissions. To inquire about submitting articles contact Athena Lee Bradley, Projects Manager. Disclaimer: Guest blogs represent the opinion of the writers and may not reflect the policy or position of the Northeast Recycling Council, Inc.