WAILUA HOMESTEADS — Eastside homeowners Dr. Robert and Magenta Zelkovsky are making history, one trip to the bathroom at a time.
The married couple owned one of about 88,000 cesspools throughout Hawai‘i, all which must be upgraded by 2050 per state mandate.
But rather than replace their cesspool using conventional methods, the Zelkovskys agreed to install a one-of-a-kind wastewater system designers believe can mitigate the statewide cesspool crisis.
“Just a cesspool conversion alone, on Kaua‘i, can go anywhere from $30,000 to $50,000,” said Stuart Coleman, executive director of the Honolulu-based nonprofit WAI (Wastewater Alternatives &Innovations), while touring the Zelkovsky residence last week.
WAI personnel said their new design, the Cinderella Greywater Combination System, will cost less than $30,000. They installed what they said is the world’s first at the Zelkovsky home, using a County of Kaua‘i Innovation Grant awarded in 2021.
Coleman said the Cinderella Greywater Combination System is also more environmentally friendly than a conventional septic tank, which holds “black water,” or human waste.
“(Septic systems) cannot remove the phosphorus and nitrogen. When that gets into drinking water, if there are drinking water wells nearby, that has major health issues,” Coleman said.
“But then, when it gets up in the groundwater and goes out to the ocean, it’s really harmful for the reefs.”
The Cinderella — a waterless toilet designed by the Norwegian company Cinderella Eco Group — eliminates this potential pollution by incinerating users’ waste. The resulting pathogen-free and odorless ash is collected in a tray at the base of the toilet, and disposed of about once every 10 days.
Contractors installed three $5,000 Cinderella toilets in the Zelkovsky home. None require plumbing, only a chimney-like pipe extending from its rear. They can be powered by electricity or propane.
WAI engineer Joachim “Joko” Schneider designed the Cinderella Greywater Combination System.
He had to account for the Zelkovskys’ kitchen sink and dishwasher, which are also considered sources of black water in Hawai‘i (due to the presence of organic material like food scraps).
Therefore, WAI buried a 1,000-gallon septic tank in the Zelkovskys’ front yard.
The tank is larger than necessary, according to WAI. But it’s the only legal model available in Hawai‘i.
“A 200-gallon tank — that would be plenty for the dishwasher and kitchen sink,” said Coleman, who believes a tank of this size will become locally available in the future.
Coleman is confident smaller septic tanks will drive down the price of the Cinderella Greywater Combination System, which is “on par or less than” a traditional $30,000 septic system.
The Zelkovskys’ remaining wastewater (greywater from their shower and washing machine) enters a mulch basin.
Should the basin ever overflow — which Schneider believes will never happen — the excess wastewater will flow into the Zelkovsky’s existing cesspool, now called a seepage pit.
The entire system has been operational for two months.
WAI will monitor the site for one year.
“We’re going to be testing this for 12 months, observing if there’s any ponding or any clogging, and writing a report to the Department of Health,” Schneider said.
He said once they show the system is safe, they can serialize it and have versions across the islands.
On the hot seat
The Zelkovskys answered questions regarding their new toilets with grace and humor.
Both noted they’ve had to adjust their bathroom routines.
The Cinderellas, while similiar in overall size and shape to standard toilets, require placement of a paper liner in their metal bowls prior to use.
The Cinderellas are also “flushed” with button, rather than a handle.
Otherwise, the couple has found no fault with their new technology.
“There’s no foul smell,” Robert Zelkovsky said.
“People have asked, ‘Well, is it hot if you have to use it two or three times?’” he continued. “I see why they’re popular in Canada and Norway … There’s just a slight warmth to it.”
The toilets are designed for up to four uses an hour. Incineration begins immediately after use and lasts for 20 minutes. A fan then cools the commode for an additional 20 minutes.
However, both processes can be interrupted and will resume automatically when toilet time is over.
The Zelkovskys had worried the Cinderellas’ fans would prove to be too loud.
But again, they have nothing to complain about.
“We have one in the hallway, which is a single wall and then our bedroom, and we can’t hear it at all,” Robert Zelkovsky said.
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Scott Yunker, reporter, can be reached at 245-0437 or syunker@thegardenisland.com.
The technology is very interesting, but it seems like the direction going forward is put the liability on the private citizen, instead of the county/kauai who is charging property taxes for the water treatment. Most people would roll their eyes at a $5000 toilet, it seems this is more the answer for an “off grid” scenario. Our current CofK water municipality is sitting on a $50 million surplus of revenue that should be used to develop a wastewater treatment systems for our neighborhoods, wailua homesteads/houselots, kapahi areas, Kilauea can all benefit from a sewage treatment plant, and it will also generate a revenue stream of tax dollars for the kunai, why haven’t they because we need to build a poorly designed roundabout by kapaa high school, Help we need a administration that actually creates infrastructure solutions to protect our groundwater. Sewage treatment systems have come a long way from the 80’s the water is very clean when its properly treated, and can be used by a developing agricultural industry that we so desire!
Thanks Ben. Yes, treatment is a very good way to go and this setup may not be the ultimate. Fitting the island with sewers is a huge task. Cinderella toilets just celebrated 25th anniversary in Norway, have won many environmental awards. And mostly used in ranger stations, hunters cabins etc. We could not have afforded this and honored to be a demonstration project, I first thought in the State, but looks like the world. In the digging water table is at 25′ below our property, old cesspool 20′ below.
I do some water test collecting for Surfrider. Every river, stream and canal polluted well over acceptable level and I feel this is a great solution.