City May Use Waste Water to Feed Crops

The next time Oxnard residents flush, they may be fertilizing a corn stalk or alfalfa sprout.

Oxnard is proposing to buy a 1,150-acre farm plot in Kern County where it will use sewer sludge to grow feed corn, alfalfa, cotton and other non-human consumption crops.

An increasing number of cities now send their sludge to the fields instead of landfills. The solid waste byproduct generated by waste-water treatment plants is rich in soil nutrients, including nitrogen and potassium.

“We are hopefully going to be diverting all of our biosolids,” said Mark Norris, Oxnard’s waste-water superintendent. “This type of project allows us to apply agricultural revenue to the cost of recycling our biosolids.”

Disposing of sludge by recycling it into farmland is nothing new for Oxnard. Since 1994, the city has been paying a company to truck about 80% of the 1,800 tons of biosolids the city produces monthly to Buttonwillow, where the processed waste is tilled into the ground.

So is Oxnard now getting into the farming business? Not exactly, Norris said.

The City Council is set to vote Tuesday on the $1.38-million land purchase and project. Oxnard is proposing to undertake the project in partnership with USA Transport Inc., a Springville, Calif.-based trucking company, which also has farming interests.

Under the eight-year partnership deal, USA Transport Inc. will be responsible for transporting the sludge and for the farm’s day-to-day operation and management. The city will participate in major farm decisions.

Once the city’s investment has been repaid, the two partners will split the income evenly, according to the agreement.

Joe Devinny, a professor of civil and environmental engineering at USC, said it is unusual for a city to go out and buy a site just for the purpose of recycling sewer sludge.

“In most places, cities sell to farmers who already are doing [the sewer sludge recycling],” Devinny said. “This is a little bit more aggressive on their part.”

But Norris said the plan is a good financial opportunity and in the long run will save the city money.

The city now pays Yakima Compost Co. $25 per ton of biosolids to truck the sludge to Buttonwillow, where it is applied to agriculture. Oxnard sends the remaining 20% of its sewer sludge to the Simi Valley Landfill at a cost of $49 per ton.

USA Transport Inc. will charge Oxnard $23.50 per ton to truck all of the city’s biosolids from the waste-water treatment plant to the farm 15 miles northwest of Wasco--a city of 14,000 located about 100 miles north of Oxnard.

According to Norris, the new project would create an immediate savings of $136,000 with a possibility of greater savings in the future.

“The current project doesn’t provide the long-term price stability,” Norris said. “This way we would have control over the use and willingness to accept [Oxnard’s biosolids].”

Norris said the project would also help Oxnard meet state requirements that call for cities to divert 25% of their waste from landfills this year and 50% by the year 2000.

Donn Fergerson, a Kern County environmental health technician, said about half a dozen sludge recycling projects exist in his county, including one involving the Hyperion waste-water treatment plant of Los Angeles.

Fergerson said he rarely hears any complaints about crops grown on sludge-treated soil, although there have been a few.

“The opposition we get is more in the order of nuisance complaints about odor or flies,” Fergerson said. “But with [tilling] within 24 hours, this is not really a problem.”

According to Devinny, farming using sewer sludge involves few risks. Cattle digest most microorganisms that cause disease so they do not end up in the meat.

Oxnard expects to gross about $150,000 to $350,000 a year from the farm by selling the crops, including corn silage, barley silage and green chop to markets such as large dairies. A study projects total silage production at 38,000 tons--enough to feed 6,333 dairy cows for one year.

Oxnard will borrow about $650,000 from a special waste-water treatment fund to launch the project. The city will pay Robert Montgomery, the landowner, $414,000 up front for the parcel. Another $226,000 will be spent to lease farm equipment and to purchase supplies including herbicides and seed.

Norris said the seller will finance the $730,000 balance owed on the land at 8% interest to be repaid within five years. The city would service the debt with operating income. Norris called the land deal a bargain.

“We had a motivated seller,” Norris said. “We were able to get a good market price.”

A report lists some of the challenges the city and USA Transport Inc. will face in their new venture. Though large dairies are expected to represent the farm’s biggest market, no potential buyers exist within a short distance, which means transport costs may be high.