The Kona Community Development Plan Action Committee met Tuesday with one agenda item leading the discussion — to hear a presentation about the Integrated Wastewater Management Plan.
Department of Environmental Management Director Ramzi Mansour presented the wastewater plan, which is a critical component to new developments.
He said there are currently 88,000 cesspools in the state, with 60% of them on the Big Island.
State law mandates that prior to Jan. 1, 2050, cesspools in the state must be converted.
“What we are trying to accomplish this fiscal year is to create a plan that includes the entire county, based on the community development plans,” said Mansour.
He said the Kona Community Development Plan written 20 years ago anticipated the entire area would be connected to sewers.
“Twenty years later, we have almost zero connections. We negotiated an order on consent agreement, and we have plans to move forward. Our biggest challenge is cesspool conversions,” he said.
With a cesspool, the discharged water comes from the house, with no separation from the shower, toilet or kitchen sink. Everything goes into a hole in the ground. There is no treatment.
“It percolates through the lava tube and makes it into our groundwater,” he said. “Most of them are on the west side of the island.”
He said there are about 5,200 priority one, 2,600 priority two and 41,000 priority three cesspools needing conversion.
“Just to be able to comply with Act 125, which passed in 2017, we have to do about 2,000 cesspool conversions every year starting today until 2050 just to be in compliance.”
Mansour said the purpose of the plan is to get the word out and let people know what their options are.
“If we wait until 2050, it will be impossible. Even today, it will be difficult to reach 2,000 a day because of lack of resources,” he said.
Some cesspools may be granted exemptions if a lot size is not adequate to allow for any conversions such as a leach field.
“If you have a sewer line fronting your property, you will be asked to be hooked up to it,” he said. “The Department of Health will issue permits for cesspool and septic systems. The homeowner’s responsibility if they have a cesspool and will be converting to an individual waste water system, will be to hire a civil engineer and a contractor that will help through the process.”
The most feasible options for the county to meet the benchmark include expanding sewer service or building decentralized systems, which consist of small cluster units within different subdivisions of about 50 homes.
“We look at the possibilities, and every option has its benefits and challenges,” said Mansour. “The benefit to connecting to county sewer is increasing recycled water. The current volume capacity at the Kealakehe Waste Water Treatment Plant is about 1.8 (million gallons per day). The facility is designed to handle 5 (million gallons per day). We have about 60% remaining capacity.”
The challenge is connecting to the sewer.
“We are trying to find out how to expand the collection system. The cost can be financed through low-interest loans over 30 years,” he said of homeowner costs to connect.
Decentralized units could cluster every four to five homes into one pod that goes into a main facility.
“You are really building an individual treatment plant. The neighborhood would need to create a sewer district, obtain property for the unit and hire operators,” he explained.
Septic would be the cheapest conversion if there is no sewer hookup.
“It’s better than a cesspool but not as good as hooking up to a waste water system,” he said. “The homeowner would take stewardship of the system. They have to make sure it is being maintained and pumped every five years, make sure there are no roots or vegetation over the leach fields, and the homeowner has to bear that entire cost. The cost would be between $30,000 and $70,000.”
A lot for a septic tank needs to be a minimum of 10,000 square feet for a leach field.
He said building a sewer system where there is no infrastructure is cost-prohibitive.
“Puna has no infrastructure in place. It would cost between $4 (billion) to $11 billion to sewer the district. We are coming in after the fact trying to build infrastructure. It’s difficult and gets very expensive,” he said. “The sooner we get these cesspools out and converted to a septic or treatment plant, the sooner we are protecting our drinking water and coastal water.”
