Augmentation in aerobic digester for better solids yields

A town in WV treats a flow of 0.10 MGD of domestic wastewater flows.  The city has seen their sludge disposal costs escalating over the last few years.  In the Fall of 2014, Maryland Biochemical approached the city about a way to reduce sludge disposal costs.

Investigation:

A sales representative from Maryland Biochemical surveyed the wastewater system and proposed a solution to improve the dewatering of the sludge by improving the quality of sludge through the use of the Toler X 4100, a bacterial blend.  The bacteria helped better flocculate the sludge and release the bound water improving decanting and gravity thickening.  A low dose of roughly 1 pound per day was added to the converted aeration basin turned aerobic digester.

Specifics related to the application:

  • In 2014 the plant shipped out 110 truckloads of sludge for disposal at a cost of $600 per truckload. This cost includes polymer use, man hours, transportation, and landfilling fees.
  • In 2015 the planted shipped out on 80 truckloads of sludge at the same cost/truck
  • Wastewater flow and wasting operations were the same year to year
  • Cost of Toler X 4100 / year – $4,200
  • Cost of all sludge removal in 2014 – $63,000
  • Cost of all sludge removal in 2015 – $48,000
  • Savings $15,000
  • Net savings of $11,000 plus per year

Added Benefit:

An added benefit was that since they began to add the Toler X 4100 to the digester, near-daily odors and odors complaints have been eliminated.  The sludge settled much more rapidly, reducing the decant time and eliminating the odors generated by sludge that turned septic having taken longer to separate.

Conclusion:

Bioaugmentation became a viable means of treating aerobic digester sludge and improving the “dewaterability” and a daily process additive enough to provide a significant cost savings to the town.