The Massachusetts Department of Environmental Protection (MassDEP) has embarked on a laudable effort to understand the problems for biosolids management in the Commonwealth and help water resource recovery facilities (WRRFs) find solutions. MassDEP most recently published the report from Part 1 of its PFAS and Residuals Technology and Management Study that intends to find sustainable approaches to managing the nearly 166,000 dry tons of wastewater sludges generated annually by the 127 WRRFs in the state.
The study’s Part 1, Technical Memorandum #1 is a deep dive into the current and near-term management of Massachusetts’ wastewater sludges. It looks at where sludge is generated, how and where it is managed, and the current and future challenges of managing it. The picture it paints is alarming. NEBRA members Tighe & Bond teamed up with Brown & Caldwell to do the study and report. They conducted an extensive survey of all the players involved in ensuring sludges move out of Massachusetts WRRFs and to their final destination.
The Tighe & Bond team created and conducted an extensive survey for WRRFs, landfills, septage haulers, residuals managers, and others handling Massachusetts sludges. The team was able to get 94 publicly-owned treatment works (POTW) survey responses from the 127 POTW surveys sent out — which equates to about 95% of the permitted wastewater flows in the Commonwealth. The responses allowed the consultants to really understand how wastewater solids are moving in and out of the state.
Massachusetts currently relies on all three management options for sludges pretty equally. According to the report, there is a lot of movement of sludges within the state as well as out of state (see Figure ES-2 from final report). The Part 1 report for this management study includes Technical Memorandum #2 on septage management as septage often ends up at WRRFs for treatment and faces the same issues with lack of outlets for disposal.
Due to projected growth within the Commonwealth, the amount of sludges needing outlets is expected to grow to 172,200 dry tons in the next five years. The study found minimal existing capacity at Massachusetts WRRFs, landfills, incinerators, and composting facilities to take on more sludges. The report points out there are no new outlets or capacity on the horizon; current outlets – like landfills – are reaching capacity and it is unlikely that new ones will be approved. For Massachusetts, most of the alternatives are currently out-of-state so the Commonwealth is especially vulnerable to what adjacent states decide to do with sludge management.
In addition to looking at where the sludges go, the report looked at what’s going on with the costs of managing sludges. The study found average costs for the last five years (2018-2023) was $156 a ton for cake and $0.16 per gallon for liquid. The cost for cake “disposal” is projected to range from $190 – 250 a ton by 2028.
Some key take aways from Part 1:
With anticipated growth in wastewater/septage sludges produced, and with no changes to regional capacity to deal with it, almost 12,000 dry tons of sludge will have no available outlet – predicted to occur in 2028. Massachusetts Water Environment Association’s Mickey Nowak dubbed that 11,826 dry tons as “orphan sludge” as it will have no “home” to go to unless changes are initiated.
Sludge management costs will increase by about 35%. That is consistent with past cost studies and on the low side for states like Maine where there are limited options.
The MassDEP is looking to develop a sustainable approach to managing sludge in Massachusetts into the future. The study takes into account economic, technical, and logistical realities, as well as infrastructure limitations. After having collected this comprehensive data on sludge and septage, the study will look next at the indirect discharges of PFAS into WRRFs and PFAS reduction and management technologies for wastewater and sludges. It will also look at the impacts of PFAS on sludge disposal methods and come up with recommendations for future sludge management in Massachusetts.
The MassDEP had an aggressive timeline to complete this study. Proposals for Part 1 were due back in January 2024 with the Part 1 report due to MassDEP by June 30th. Part 2 proposals were due in late March with deliverables expected in early 2025. The Tighe & Bond/Brown & Caldwell team were awarded the Part 2 work which is well underway now. NEBRA looks forward to seeing what that study recommends to the MassDEP as actions to take to keep the solids moving. If nothing else, the report could be a valuable contribution to discussions with the legislature about how to manage wastewater sludges and septage generated by the 7 million people flushing their toilets every day.
Findings like this make it urgent:
“It is therefore estimated that approximately 7% of the sludge generated in Massachusetts in 2028——the equivalent of nearly 2,500 tractor trailers full of sludge— will not have a clear outlet among existing options in the region (Section 7.1.2).
Quote from Current and Near-Term Management of Massachusetts Wastewater Sludge
Bottom Line: Massachusetts cannot grow commercially or residentially unless something is done to ensure future sustainable outlets for wastewater sludges.
Information about the full study, including the Part 1 report: Residuals & Biosolids | Mass.gov.