Post 27 in a series. When Green Turns Brown is an examination of a small town’s digester-energy project, in which Whitewater, Wisconsin would import other cities’ waste, claiming that the result would be both profitable and green.
One hears from local officials that spending over twenty-million on Whitewater’s wastewater treatment plant is a necessary upgrade. When considering the disposal of waste from the plant, however, there will be no upgrade whatever in the safety of what’s produced and spread nearby – there will simply be more of it, from received from faraway places.
That’s not my opinion – it’s the written assessment of the latest vendor behind this project, and the assessment that Whitewater’s municipal officials have, themselves, touted:
4.3.7 BIOSOLIDS REUSE
Biosolids disposal at the Whitewater WWTP follows the requirements of WAC Chapter NR 204, Domestic Sewage Sludge Management. The historical biosolids data show low metal content and therefore satisfy one of the requirements for “high quality” sludge. The Whitewater WWTP generates Class B biosolids based on the fecal coliform level in the solids being land spread.
Class B biosolids by definition have a higher level of pathogenic bacteria than Class A biosolids. Local farmers have accepted the Class B sludge for disposal on agricultural land. The majority of POTWs in Wisconsin produce Class B sludge.
Producing Class A sludge would provide the following advantages over Class B sludge:
1. The sludge would contain a lower level of pathogenic bacteria. Class A biosolids must have a fecal coliform concentration of less than 1,000 most probable number (MPN) per gram total solids.
2. Land application site evaluation reports would not be required and bulk sludge land application reports would not need to be filed with the WDNR.
3. Whitewater would not need to receive approval from the WDNR prior to applying sludge.
4. More sites would potentially be available to apply the sludge.
5. Since Class A biosolids have lower levels of pathogens, there is a lower threat to human health, and therefore, fewer measures are required to minimize human contact with the sludge.
To be considered “exceptional quality sludge” or Class A, the sludge must receive prescribed treatment to reduce pathogens and vector attraction. The prescribed treatment options available include lime stabilization, composting, heat drying, thermophilic aerobic digestion, temperature phased anaerobic digestion, heat treatment, pasteurization, or an equivalent process to further reduce pathogens. Based on the current acceptance of Class B biosolids for beneficial reuse and the increased costs necessary to comply with Class A biosolids regulations, it is assumed the Whitewater WWTP will continue to use the current methods of biosolids stabilization and disposal for the foreseeable future.
See, Donohue Technical Memo 2, Flows, Loadings, and Existing Conditions, http://www.whitewater-wi.gov/images/stories/public_works/wastewater/Donohue_Technical_Memo_2_-_Flows_Loadings_and_Existing_Conditions.pdf.
Before: Pathogenic bacteria, a threat to human health, and needed measures required to minimize human contact with the sludge.
After: Pathogenic bacteria, a threat to human health, and needed measures required to minimize human contact with the sludge, in even greater quantities, trucked from faraway cities that don’t want it near their residents, to Whitewater.
For it all, this is what City Manager Clapper describes as “probably the greenest process we have in the city.”
WHEN GREEN TURNS BROWN: Mondays @ 10 AM, here on FREE WHITEWATER.