Some Updates on Phosphorus (P) and Biosolids/Residuals Management
Phosphorus in biosolids and other residuals continues as a high-interest topic. NEBRA provides background on the issue here, including a link to a useful WEF Fact Sheet. As one NEBRA member pointed out recently, the P issue continues to grow, as agriculture and water quality regulators focus more on controlling P from non-point sources. There are lots of rules being shaped right now – focused on fertilizers and manures mostly. And sometimes such rules don't work well for biosolids. The biosolids profession needs to watch closely and be involved.
Here is a smattering of recent developments related to P and biosolids/residuals management:
- Treatment Plant Operator magazine (TPO) gets the P problem faced by water resource recovery facilities (WRRF) and their biosolids management programs. See the recent editorial by editor Ted Rulseh. They also highlighted the use of "adaptive management" in efforts around Madison, WI to reduce total P runoff by going after the most cost-efficient solutions (e.g. non-point controls) rather than relying heavily on expensive treatment facility upgrades.
- The Massachusetts Department of Agricultural Resources (MDAR) has proposed an update to its Plant Nutrient Regulations that went into effect in 2015. But the update, proposed last fall, seems to be delayed. NEBRA offered assistance in reviewing the new regulatory language (because the Regulation has been plagued by confusing writing from the start) and urged another public comment round. But MDAR is not interested in further input, it seems. MDAR staff have not replied to recent requests for further information.
- Vermont is finishing an updated P Index that includes source coefficients for biosolids. Meanwhile, a manure digestion system in St. Albans includes P extraction, thus reducing the total P in the land applied digestate. However, that project was reportedly on hold, as of April 2017.
- The Sustainable Phosphorus Alliance held a Phosphorus Forum on May 19th in Washington, DC, providing updates on the culmination of a 5-year research effort that was facilitated by a consortium led, in part, by Arizona State University (which houses the Alliance). Information & presentations from the symposium are here, including a long calendar of upcoming P events around the globe. The Alliance's blog includes discussions of biosolids and an entry by the Rich Earth Institute of Brattleboro, VT, regarding urine separation. The P Alliance seeks members and has just started a recycled fertilizer focus group - very much focused on biosolids and other residuals.
Maryland is still going forward with its very stringent P regulations, which mostly become effective in 2018. In part because of the new regulations, the state reports losing 3 dairy farms a month; the regulation is too expensive to meet. The agriculture regulatory agency, MAMWA, is considering integrating the Water Extractable (WEP) test and P Source Coefficients into the state's P Site Index, which would help biosolids recycling some. But there are other obstacles: for example, the state agriculture department pays for cover cropping where manure is used, but won’t where biosolids are involved, because they think biosolids companies should pay for the required cover cropping. Plus, in many situations, allowable biosolids application rates under the new regulations will be so low as to be physically impossible; a spreader just can't spread such very low rates.
Wisconsin has an advanced nutrient management tool, SNAPPLUS, which includes specific inputs for biosolids, just like for manures and fertilizers. Now, the tool is being modified to integrate Water Extractable Phosphorus (WEP) test results. WEP tests of biosolids and other materials provides a more accurate indication of the environmentally relevant portion of the the total P in a soil or soil amendment. WEP is a more reliable indicator than agronomic tests (e.g.Mehlich III or Modified Morgan) of the potential actual impacts to neighboring water bodies to be expected when a particular P-containing material is added to soil.
- Austria has followed Switzerland and Germany in opting for mandatory P recovery from municipal sewage sludge. The draft Federal Waste Plan 2017 (Bundes-Abfallwirtschaftsplan) includes a ban of direct land application or composting for sewage sludge generated at Wastewater Treatment Plants with capacities of 20,000 p.e. or above within a transition phase of 10 yeras (see chapter 7.5 in the waste plan part 1, link below). Alternatively, these WWTP will have to recover the P from sludge onsite, targeting P contents below 20 g P / kg dry solids or have to deliver their sludge to sludge mono-incinerators. The P is then to be reovered from the sewage sludge ashes obtained. This regulation will cover 90% of the P contained in the Austrian municipal wastewater. Austrian Ministry of the Environment and draft waste plan (auf Deutsch).