Mushroom farmer confident aeration will kill most odors

February 5, 2001

Press Democrat Staff Writer

Puffing air into mounds of decomposing straw
will make the Petaluma Mushroom Farm's new
home more palatable to neighbors, farm
operators say.

The proposed farm on Roblar Road will be the
first in California using a new method to curtail
the odor from processing 500 tons of compost a
week, said Duncan Soldner, the project

The farm is under county orders to move its
composting operation, and residents of
Bloomfield aren't happy with the prospect of
having the farm a half-mile from their rural hamlet
near the Marin County line.

"We're concerned that it's more of a factory than
a farm," said Caroline Courtright, an organizer of
the Bloomfield Rural Alliance. "This is not at all a
venture like the ranches and farms around here."

Courtright's group will appeal the county Board
of Zoning Adjustment's approval of the farm's
plan to move to an 89-acre site at Bodega
Avenue and Roblar Road.

A hearing before the Board of Supervisors could
come in March, and mushroom farm spokesmen
say they have no qualms about it.

"We feel we can answer all their questions," said
Eric Koenigshofer, the farm's attorney.

But Susan Brandt-Hawley, the alliance's
attorney, said problems associated with the
existing farm on Thompson Lane, about 11/2
miles west of Petaluma, require more detailed
analysis, including an environmental impact

Mushroom farm owner David Cerini faces a
Nov. 1 deadline -- imposed by court order and
county permit conditions -- to move his
composting operation away from Thompson

Growing fungi, which sprout in nature from
decomposing plant matter, requires tons of
compost. But it is pungent, which has drawn
complaints from Thompson Lane neighbors.

County inspectors also cited the farm for various
code violations before it was ordered to relocate
its composting operation.

Cerini, a former stockbroker, proposed a new
farm on Middle Two Rock Road last year,
prompting a protest by dairy country residents
who helped him find the Roblar Road property.

"It's hard to imagine a site in Sonoma County
that would be better suited to this activity,"
Koenigshofer said last week.

"Just moving the problem from one place to
another isn't necessarily a solution,"
Brandt-Hawley countered.

But Soldner said the new farm will employ
cleaner, more energy-efficient composting and
mushroom growing processes, and disputed
critics' contention that it is "experimental

Aerated floor systems, also known as "Dutch
technology," are widely used in Canada,
Mexico, Europe, India and South Africa, but are
virtually untested in the United States, he said.

The only U.S. farm using entirely forced-air
composting is in Stevensonville, Mont., an
operation run by Vaughn Paul, Soldner said.
Paul and Soldner were partners with Cerini at
Petaluma Mushroom Farm in the 1980s, but no
longer own any part of the business.

California is the nation's second-leading
mushroom producer with 117 million pounds a
year, according to Department of Agriculture
statistics. Pennsylvania is tops with 310 million
pounds, more than one-third of the 870
million-pound national mushroom crop.

Mushroom farm compost -- essentially a mixture
of straw and chicken manure, soaked with water
and left sitting for four weeks on a concrete
wharf -- is at best earthy smelling.

Neighbors of the Thompson Lane mushroom
farm have complained since 1983 of rotten
odors that force them to close their windows and
stay indoors.

Soldner said foul odors result when oxygen runs
out in the center of the long piles, or ricks, of
shaggy brown compost, allowing cold anaerobic
decomposition to replace the hot aerobic decay

Anaerobic bacteria emit ammonia and sulfur
smells, whereas aerobic bacteria absorb them,
he said.

Compost brewing on the new farm's two-acre
concrete apron will smell like freshly turned earth
-- "like somebody rototilled the back yard,"
Soldner said.

Soldner said the compost wharf of the new farm
will be laced with 6-inch pipes capable of puffing
air into the compost mounds when
computer-linked probes sense a lack of oxygen.
By maintaining aerobic decomposition, the worst
smells will be eliminated, he said.

He also noted that the prevailing wind on Roblar
Road is from the west, blowing away from

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