In Puak艒, a coastal community on Hawai鈥榠 island, residents have been for over a decade to reduce the destructive impact their wastewater has on the nearby coral reefs, and a workable alternative to cesspools is finally gaining momentum.
Puak艒 For Reefs, the volunteer-run nonprofit behind the effort, has drawn up plans to put in what鈥檚 called a low-pressure liquid-only sewer system, the only viable alternative to the cesspools and septic systems in low-lying coastal places. And they have been working with Hawai驶i County on a plan to fund and build it, in hopes of creating a model that can extend far beyond Puak艒.
Faced with a daunting mandate by the state to convert over 49,000 cesspools on the island by 2050, a goal Mayor Kimo Alameda has said , the county is in need of a solution, especially for coastal areas.
And while Alameda about the value of a sewer project in Puak艒 last fall, the mayor and his staff at the county have now gotten on board.
鈥淭his is the most organized community right now. They have a plan. This could be the model for the state,鈥� Alameda told Civil Beat. 鈥淎fter Puak艒, it could be Kahalu鈥榰. After Kahalu鈥榰 it could be Miloli驶i. After Miloli驶i, it could be Keaukaha or any of those kinds of Priority One coastal areas.鈥�
Cindi Punihaole, director of the Kahalu鈥榰 Bay Education Center, has been working closely with Puak艒 For Reefs in recent months to develop a similar plan for a low-pressure sewer system near Kahalu驶u. The popular snorkeling destination is located on the Southern end of Ali驶i Drive, about a quarter of a mile away from where the existing sewer line ends, and as a result, it is surrounded by cesspools. As in Puak艒, the reef has suffered as a result of the nitrogen runoff.
鈥淵ou look at the bay, it鈥檚 beautiful,鈥� Punihaole said. 鈥淏ut if you go into the bay, it鈥檚 not.鈥�
She runs a program educating tourists about reef-safe sunscreen, and her center has succeeded at closing the beach during cauliflower coral spawning season each September. However, Punihaole said, those efforts combined won鈥檛 bring back a healthy reef without cleaner water.
鈥淲e need to remove these stressors,鈥� she said.
Pulverizing Waste To Reduce Footprint
After several years working with nonprofit partners and University of Hawai驶i Hilo researchers to study the impact of their effluent on the reefs, Puak艒 For Reefs hired an engineering firm to analyze potential solutions in the region. It came back in 2019 with a surprisingly doable solution.
Some homes in Puak艒 have cesspools and others have septic systems, which filter the waste through gravel leach fields. But even in the latter case, large quantities of nitrogen are still filtering to the reefs. So the group went looking for an alternative.
Removing all the wastewater through a sewer system that routes it to a water treatment plant would ensure that it gets filtered better and 鈥� ideally 鈥� gets used on land, where it is further filtered before it eventually drains into the groundwater or the ocean.
Most sewer systems use gravity to move waste through a series of very large underground pipes 鈥� up to 60 inches wide 鈥� to a centralized water treatment plant. Those large pipes are impractical in many areas of the Big Island because of how deep they would need to be buried in rocky places, and how costly it is to dig into lava.
The alternative, low pressure system on the table in Puak艒 would pulverize the waste with a grinder, allow the liquid to rise to the top, and move it through a relatively small, 6-inch pipe. Because of its size, the pipe can be buried much closer to the surface and costs much less to install.
The bulk of the waste can travel through the pipe, and the remaining waste will be held in a small tank that will need to be pumped out every five to eight years, much like a septic tank. Unlike a gravity system, low-pressure systems keep all the waste contained in a way that won鈥檛 be impacted by surges of rain or ocean water during king tides and storms that cause flooding.
鈥淭hey compared a low-pressure system to a gravity-fed system, and not only would the traditional gravity-fed not work, but it was 10 times more expensive than the low pressure system 鈥� $120 million versus $12 million,鈥� said Karen Anderson, president of Puak艒 For Reefs.
Since then, the group has worked to share information with their community, engaged dozens of experts and planned a route for the sewer using public input. In the meantime they have engaged three different county administrations.
Now, they may finally have a funding model that can work and buy-in from the county.
Creating a Model
Low-pressure systems have existed since the 1980s, but Puak艒 would be an early adopter in Hawai驶i. The developers behind Kohanaiki, a high-end development surrounding a golf course on the Kona coast, a low-pressure system for its 400 planned homes. And members of Puak艒 For Reefs 鈥� and Punihaole鈥檚 new spinoff group, Kahalu驶u For Reefs 鈥� also met with planners from Vero Beach, a community on the east coast of Florida that installed such a in 2015.
The Puak艒 sewer system, which will serve around 200 homes, has a planned route and a destination for the wastewater: the American Water Plant in the neighboring Mauna Lani resort. And Anderson said the group recently had a kickoff meeting with Hawai驶i County Department of Environmental Management about the design. The group is hoping to wrap up the planning and permitting process by the end of 2027 so they can start construction in 2028.
Meanwhile, the Kahalu驶u group is working with Honolulu-based Limtiaco Consulting Group on a project design for a low-pressure sewer system for between 50 and 70 of the 300 homes that need to be converted in the immediate area. It鈥檚 a big step, but Punihaole emphasized that having a design doesn鈥檛 guarantee funding.
Indeed, it will cost an estimated $40,000 to connect each home with a cesspool to the sewer system in Puak艒. Those with septic systems will pay less because connecting to the sewer will require a smaller modification to their existing systems.
The community group has applied to become a designated Community Facilities District, which would involve having the county create a bond that provides seed funding for the sewer and then pays it back through a special tax paid by the property owners over several decades. That approach could help ensure that lower-income residents don鈥檛 get unfairly hit with high upfront fees in an area that is home to both high-end vacation rentals and long-time local residents.
鈥淲e want to make sure that everyone can afford the connection for their home,鈥� Anderson said. 鈥淥ur goal is that it can all be financed through a special revenue bond that can be paid off over 40 years.鈥�
The group also hopes to raise money from local donors and philanthropists who want to see the reef bounce back. If that happens, they said, the ideal would be to roll the funds from one coastal community to another 鈥� so that as one project gets paid back, the funds get used to seed the next. Other communities looking toward low-pressure systems include the fishing village of Miloli驶i and a small cluster of houses in H艒naunau, immediately north of Pu驶uhonua o H艒naunau National Historical Park.
鈥淚t鈥檚 a model that鈥檚 never been tried,鈥� Alameda said, 鈥渂ut I give them credit because anything is better than nothing.鈥�
The county鈥檚 departments of finance and environmental management are both working closely with Puak艒 For Reefs, at Alameda鈥檚 request. He also signed an Memorandum of Understanding with the group to move this project forward.
Alameda said he has some concerns about prioritizing one coastal community over others, but he acknowledged that creating a model is valuable and should make it easier for other communities who want to take similar steps 鈥� and that can benefit the whole island, not to mention the reefs, which are a vital shared resource.
Alameda also stressed that the homeowners will still be on the hook to pay a portion of the cost.
鈥淎t the end of the day, it鈥檚 not going to be free to either transfer to a septic system or to connect to a sewer line,鈥� he said. 鈥淎nd everybody wants it to be free. I mean, I would like that for my house too.鈥�
Changing The Industry
Rick Gaffney, a former member of the county鈥檚 Environmental Management Commission, started a community working group focused on keeping wastewater out of the ocean. It meets once a month, includes Punihaole and members of Puak艒 For Reefs and has helped keep the conversation front and center for the county.
Gaffney said he is optimistic about the chain reaction the Puak艒 group envisions.. He added that while most wastewater projects are executed by one of two or three large companies, Puak艒 For Reefs is playing a very different numbers game.
鈥淭hey have reached out to 98 different contractors for pre-bids. The more people who bid, the more likely that you鈥檙e going to get a realistic price,鈥� he said.
Gaffney takes that aspect of the effort as a good sign about the future of community-scale sewer development in Hawai驶i. Working with smaller companies also has the potential to help build the industry 鈥� an important piece of the overall cesspool conversion puzzle.
Stuart Coleman, executive director of Wastewater Alternatives and Innovations, sees low-pressure liquid-only sewer systems as vital to keeping high-nutrient wastewater out of the ocean. The systems, he says, can aid in building a circular system for waste, water and nutrients 鈥� most of which are currently being wasted 鈥� but would do much more good on land.
Smaller systems allow the water to be used locally, because it wouldn鈥檛 need to be transported or piped out to other locations.
鈥淚f you鈥檙e going to go to all that effort to treat water, let鈥檚 reuse it and keep it on land,鈥� Coleman said. 鈥淎nd especially in leeward areas across the state, use it to irrigate a green belt, which also serves as a fire break and a sediment break.鈥�
Luke Gianni, a spokesperson for American Water, said the company is not currently using the water from the Mauna Lani plant at the surrounding resorts.
Smaller, decentralized sewers and treatment plants, Coleman added, allow you to turn waste into a resource and keep it in communities where it can be used instead of drinking water.
鈥淭hat way, you鈥檙e keeping it local,鈥� he said, 鈥渘ot spending all that energy and money pumping or transporting it.鈥�
Punihaole is collaborating with scientists at UH Hilo and the Reef Check Foundation, a community science nonprofit, to survey the reef and document the state of the coral and the fish in the bay, 鈥渟o that we have a true baseline of that area, and as we do the conversion of the cesspools, then we can do another survey,鈥� she said.
At age 75, after decades of studying and nurturing the reef, Punihaole seems convinced that a real turning point is just around the corner. And the fact that so many people are meeting regularly 鈥� in Gaffney鈥檚 working group 鈥� and that the homeowners in Puak艒 have 鈥渢aken her under their wing鈥� gives her hope, she said.
鈥淚鈥檝e gone through times when people didn鈥檛 want to share information with one another. But I think we鈥檙e past that now,鈥� Punihaole said. 鈥淲e need to create momentum so that all of us together can make a difference.鈥�
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