The U.S. Environmental Protection Agency is conducting a sewage study after finding chemical indicators of human waste in near-shore waters of Kaanapali.
State and federal officials said while bacteria levels in near-shore waters do not exceed public health standards, pharmaceutical chemicals and other chemicals associated with sewage have been found in the area close to Kahekili Park, about a third of a mile seaward of the Lahaina Wastewater Reclamation Facility.
David Albright, groundwater manager for the agency in San Francisco, said a $250,000 study is trying to trace chemicals put into sewage injection wells at the plant to determine how long it takes for the waste water to surface in the ocean.
Albright said if the waste water from the plant gets into the ocean too quickly, the water isn’t filtered sufficiently.
"It’s an open question," he said. "I do not know when the study will reach its conclusion … (the) EPA is hopeful of having some information to share with the public by the end of the year."
Kahekili Park is in the north Kaanapali area on Maui where major algae blooms occurred in 1989, 1991 and 2001, prompting some merchants to complain about the loss of visitor business.
While scientists say that the blooms were probably caused by a number of factors, University of Hawaii botanist Celia Smith notes that waste water appears to stimulate algae growth.
As of mid-2009, state officials have imposed a ban against the taking of some kinds of herbivore fish and sea urchins that eat algae along a one-mile section of north Kaanapali.
Albright said while an area seaside of the Kihei Wastewater Reclamation Facility showed similar chemical markers, the current study has focused on the Lahaina Wastewater Reclamation Facility because of its proximity to the ocean.
The waste-water plant in Kihei is about a mile from the ocean, compared with the plant in Lahaina, which is about one-third of a mile away.
Albright also said unlike the Kihei Wastewater Reclamation Facility, the plant in Lahaina does not fully treat all the sewage.
He said the county partially disinfects waste water at the Lahaina facility with chlorine and ultraviolet light.
Albright said while there are other injection wells in the state, the injection wells on Maui are unique in their size and handle a much higher volume of disposed wastewater.
He said the vast majority of waste water on Oahu is treated and discharged through deep water ocean outfalls regulated by state health officials under the federal Clean Water Act.
Some 4 million to 6 million gallons of sewage are injected into the ground daily at the treatment plant in Lahaina.
Two injection wells were constructed in 1979, and two more were added as part of a 1985 plant expansion.
In 1991, the county wanted to increase the number of injection wells possibly to 12.
But state and federal official encouraged the county to seek alternative means, including the re-use of treated sewage water.
A U.S. Geological Survey study published in 2008 found pharmaceuticals, synthetic musk fragrances, caffeine and other chemicals associated with human waste in near-shore areas close to submarine springs in Kaanapali.
USGS officials said a key factor in detecting and mapping the waste-water plumes was sampling very close to shore and in very shallow water.
Officials said a consultant’s attempts to detect the treated sewage at Lahaina in the 1990s were inconclusive, having focused farther offshore in water mostly 10 to 30 meters deep.
Geological Survey hydrologist Chip Hunt, who conducted the 2008 study, said based on a modeling study, he estimated the waste water in Kihei reached the ocean in about a year.
Hunt said he did not do a modeling study for the Lahaina Wastewater Reclamation Facility.
Maui County Mayor Alan Arakawa said the county is in the process of fully treating the sewage at the Lahaina plant with ultraviolet light and committed to finding a way to re-use the treated sewage.
But Arakawa, a former waste-water plant supervisor in Kahului, said federal officials were speculating as to the connection between human waste and the waste-water treatment plant in Lahaina.
He said with storm runoff from the mountains and sea currents, the chemicals associated with human waste could have come from other sources.
