FPUD to continue hauler service for biosolids

The Fallbrook Public Utility District will continue to use a hauler service to dispose of biosolids.

FPUD's board opted for continuing to haul rather than to repair the existing sludge heat dryer or purchase a new dryer. That decision was a 5-0 vote at the May 24 meeting.

"We determined that the cost of repairs and cost of natural gas are significantly higher than the cost of hauling," said FPUD General Manager Jack Bebee.

FPUD purchased a Fenton sludge heat dryer in 2006 to offset hauling costs. If biosolids are processed to a higher level through thermal drying or other means, they can be considered Class A biosolids and used like ordinary fertilizer. Biosolids which are not processed must be disposed of in a landfill or out of state.

When FPUD purchased the dryer, its expected service life was 15 to 20 years. The dryer was requiring repairs with increasing frequency, and it has been out of service since December 2020 when the boiler system was deemed to be inoperable with a significant repair cost. During 2019, seven repairs costing FPUD $46,682 were required for the dryer.

R.F. MacDonald provided a packaged quote in February to replace the boiler. The $220,000 price would include a new thermal heater unit, installation, system integration, and start-up. If the Fenton dryer lasted an additional three years the average annual cost for the repair would be $73,333. When the annual operations and maintenance cost is added, the annual cost for the option to repair the existing dryer would be $197,664 not including any other repairs the dryer might need over the three-year period.

The Gryphon dryer utilizes a newer technology than the Fenton dryer. Its annual energy costs would be $37,000 compared to the $61,000 energy expense for the Fenton dryer. Those numbers utilize the San Diego Gas & Electric rate increase which took effect March 1 and raised natural gas prices by 16% and electricity costs by 5.2%.

The regulatory and labor costs for the Gryphon dryer would not change significantly if at all from the Fenton dryer costs, and the total annual operations and maintenance costs for the Gryphon dryer are estimated at $92,935. The $2,025,000 initial capital cost for a new dryer equates to $101,250 annually over 20 years, so the total annual costs for a new dryer would be $194,185.

FPUD produces approximately 375 tons of Class A biosolids. The estimated annual cost to continue to haul biosolids is $162,500. FPUD's water reclamation plant is designed to allow for the hauling of biosolids when the dryer is not operational, and the plant infrastructure includes a dedicated storage and discharge zone for the trailer and a conveyor system with various discharge points. FPUD's only labor costs for hauling are for operating the conveyor and moving trailers, which consume approximately 2 1/2 hours per week of staff time.

In March, FPUD's board approved a contract to upgrade the conveyor system with a programmable logic controller system which will allow remote operation through a supervisory control and data acquisition system and thus reduce staff labor time to operate the conveyor. The hauler rather than FPUD would be responsible for many of the regulatory requirements, and the labor and maintenance savings would allow FPUD staff to dedicate more time to other district facilities.

Hauling carries the risk of increased disposal costs and additional regulations, so FPUD may return to processing biosolids at the treatment plant if hauling is no longer the most cost-efficient option. "We will keep a close eye on this to evaluate the potential for getting a replacement dryer as technology and regulations change," Bebee said.