An artist's rendering shows the state's proposed sewage-to-fertilizer processing plant, indicated with red arrow, to be located at the Sand Island Wastewater Treatment Plant.
Advisers say sludge
test is a waste
Testing for the safety of a fertilizer would
not prove anything, say city consultants
City consultants dismissed as unrealistic yesterday a proposal for testing fertilizer made from sewage sludge to see if it would grow harmful bacteria when spread on soil.
When mixed with natural soils, any fertilizer -- whether from sewage sludge, animal waste or chemicals -- would promote the growth of whatever organisms are in the soil, said Charles Gerba, an environmental health specialist with the University of Arizona.
On that basis, University of Georgia microbiologist David Lewis' suggestion that the city test for growth of pathogens in sludge-fertilized dirt would not prove anything, scientists hired by the city said in presentations yesterday about the safety of a proposed sludge-to-fertilizer plant.
The City Council votes tomorrow on whether to grant the facility at the Sand Island Wastewater Treatment Plant a necessary zoning permit.
Most microbes are killed off at temperatures above 140 degrees Fahrenheit, and the Synagro plant will run at 185 degrees, said Jeffrey MacDonald, with the Milwaukee Metropolitan Sewerage District, which has operated the oldest sludge-to-fertilizer plant in the country since 1926.
To be given the EPA "Class A" label expected for Honolulu's plant, a sludge product must "reduce any pathogens that might be present to below detectable limits," said James Smith, an EPA engineer who addressed yesterday's meeting by phone.
An EPA consent decree that orders Honolulu to upgrade its Sand Island sewer plant includes the requirement that sludge, the muddy solids left when water is removed from sewage, must be put to "beneficial use," said city Environmental Services Director Frank Doyle.
If the city does not meet its EPA deadlines, it could face large fines.
Doyle said he hopes the city uses the free fertilizer on its parks and other properties, because he believes it is safe.
Roger Fujioka, a microbiologist with the University of Hawaii's Water Resources Research Center, said the system Synagro proposes for Honolulu "uses the best available treatment and process."
Fujioka added that he is not sure testing sludge from other plants would prove anything about the Honolulu plant.
Instead, he recommended that the city "build the plant, make sure it's operated correctly" and regularly test for harmful bacteria during its first year.
Fujioka said UH researchers would have to be contracted to do that work and that he believes it would confirm data from Synagro and the EPA.
Councilman Romy Cachola, whose district includes Sand Island, said after yesterday's presentations that he still thinks the city should do testing before building the plant.
"The community still thinks if you promised testing, you've got to do it," Cachola said. "When you agree on a test, don't back away from it."