We take the humble toilet for granted, rarely stopping to think about where all that waste goes. But in Hawai‘i, the reality for thousands of residents is that the plumbing leads straight to a big hole in the ground. There are approximately 88,000 aging cesspools across the state, and some of that untreated waste is making its way into our streams, oceans, and drinking water, leading to illness for swimmers, paddlers, and surfers, as well as stressing our coral reefs and native fauna. Change is on the horizon, however; some innovative new solutions have reached the testing stage and Hawai‘i, “the Aloha State,” could be at the frontier of a toilet revolution.

Dirty Secret
Cesspools are normally associated with poor countries where efficient sewage disposal is simply too costly to implement. Yet here we are in Hawaiʻi, with 53 million gallons of human waste pouring untreated into the ground annually, according to the Hawai‘i State Department of Health (DOH). The state faces genuine challenges with waste water management, including a high number of rural communities who cannot connect to sewer lines and local geology or a shallow water table which makes traditional upgrade options (such as septic systems) less effective. That means that around half of our cesspools pose a risk to water resources. Heavy rain can exacerbate the situation, with flood waters carrying raw sewage into waterways.

The untreated cesspool sewage can introduce pathogens into the ocean and water table, including Hepatitis A, salmonellosis, gastroenteritis, conjunctivitis, and cholera. The effluent also contains nutrients, like nitrogen and phosphorous, that damage the ecosystem, especially coral reefs. For a state that attracts tourists to the islands for its unique natural beauty, and for recreational activities such as snorkeling and swimming, that is a big problem. But it’s the locals who really suffer year-round from contaminated water for fishing, recreation, and potentially, drinking.

The problem is likely to become worse as climate change causes flooding events to be more frequent, which could lead to overflowing cesspools. The residents of Kauaʻi discovered this first-hand during the catastrophic floods in April of 2018 when cesspools overflowed, and medical teams had to be deployed after the influx of dirty water.

The legislature and DOH acknowledge the potential problems that cesspools cause and have been actively searching for solutions. One of the biggest stumbling blocks is financial. A cesspool requires little maintenance. Putting in a septic system or advanced treatment unit (ATU), on the other hand, is expensive and requires regular check-ups and pumping to keep it working. Change is needed, and it is coming, but so far, it is not cheap.

Turning the Sewage Tide
Regulation on sewage management has failed to keep up with population growth in Hawaiʻi. Large capacity cesspools were banned in certain areas in 1992 and then completely in 2016, but homeowners are not currently required to upgrade old systems. However, the state is putting policies in place to address this critical issue. In 2017, the Hawai‘i State Legislature passed Act 125 which requires that all cesspools be upgraded by 2050.

A subsequent report published by the DOH in December 2017 identified 14 priority areas throughout the state where cesspool upgrades are critical to protect public health and the environment.

Traditionally, septic systems have been the upgrade of choice, but there’s mounting evidence that they won’t be sufficient as the leach fields can still lead to pollution, especially if they are poorly maintained. Instead, the gold standard for residential properties is an ATU which uses aerobic biological processes to destroy pathogens and reduce nutrient loads. They do, however, require regular maintenance, as well as energy to power blower motors, which makes it cost prohibitive for many homeowners.

Counting the Cost of Cesspools in Kauaʻi
The town of Hanalei in Kauaʻi is a classic example of the problem in Hawai’i. The DOH describes it as an area where “cesspools have the potential to impact sensitive waters.” Many homes were built when cesspools were still legal. As a result, several studies have suggested that sewage may be finding its way into streams and the ocean from up to 170 cesspools in the Hanalei watershed.

Within the ahupuaʻa (watershed), cesspools are not the only problem. There is runoff from grazing and taro fields; pigs and invasive plant species are causing damage to upland areas which result in increased sedimentation; and the list of other potential pollution sources is long. Some pathogens and nutrients even enter the system as a result of natural ecological processes.

But clearly, the presence of cesspools near streams, rivers, and Hanalei’s shallow water table is a major driver of poor water quality. This was confirmed by a 2010 study by Dr. Karen Knee of Stanford University, which used caffeine as a marker to link key pollution problems to manmade sewage (since pigs and birds aren’t known to ingest coffee).

The effects of this pollution are serious. The DOH report says, “Local residents have long been reporting excessive incidents of ear infections, staph infections, and gastrointestinal problems after swimming in Hanalei Bay.” Tests of ocean water found fecal bacteria containing E. coli and enterococci, much of it coming from the Hanalei River. The report noted “a positive correlation … between these parameters and urbanized or cultivated areas and a negative correlation with forested areas.”

Makaʻala Kaaumoana is the executive director of the Hanalei Watershed Hui, a non-profit which looks after the ahupua‘a of Hanalei. The organization has been monitoring water quality and working with residents and the authorities to replace aging cesspools in the watershed of the Hanalei river.

“We moved the dial,” Kaaumoana says. Water quality samples collected at replacement sites before and after cesspool replacements showed reductions in nutrients and bacteria.

But it wasn’t enough. Pathogens were still making people sick after they swam in the bay. The nutrient and bacteria load also threatened the natural environment. The waters around Hanalei are home to the endangered Hawaiian Monk Seal, Green Sea Turtle, and native fish such as mullet (ama‘ama) and flagtails (aholehole). The bay also has corals which are being considered under the Endangered Species Act. Corals are badly affected by sediment, which physically buries them or reduces the light needed for their symbiotic algae to photosynthesize.

In 2015, Kaaumoana was involved in a grant funded by the Environmental Protection Agency (EPA) via DOH. If she could persuade 15 of the 75 homeowners with cesspools affecting water quality in Hanalei Bay to commit to upgrade to ATUs, the grant would pay for half of the work. That would stop the seep of untreated sewage from their homes and vacation rentals under the beach and straight into the bay.

Kaaumoana says it was a hard sell. “They didn’t want to take on the annual maintenance and electricity costs, even though we estimate the electricity amounts to just a few hundred dollars a year.” Ironically, Kaaumoana said that the same homeowners would complain about getting ear infections and itchy skin rashes when they surfed or swam in Hanalei Bay. “I had to tell them, they were swimming in their own poop – literally.” By the time she got a handful of people convinced, the grant window had closed.

Joel Guy of the Hanalei Initiative thinks that homeowners should get more help. “The onus shouldn’t be on just the homeowners to fix the problem; if we want economic development, we have to pay for it as a community.” The Hanalei Initiative is hoping to eliminate the worst of the cesspools by paying for them outright.

Kaaumoana doesn’t oppose this idea, but notes that there will still be maintenance costs. She worries that having someone else pay for the treatment units might mean that homeowners don’t take full responsibility for them.

Guy plans to press ahead. “I want to surf now,” he says, “not in 2050 when the law bans cesspools.”

Cesspools are covered pits or holes buried in the ground which receive human waste from a pipe. They are typically constructed of concrete or brick and have openings along the walls of the pit. Sometimes they are surrounded by gravel or sand material to allow better movement of liquid waste into the nearby soil. Waste solids eventually settle in the bottom of the tank and require pumping. If groundwater levels are close to the bottom of a cesspool, or the surrounding soil material is saturated or very porous, harmful pathogens and nutrients can be easily transferred to underground aquifers, the ocean, or other waterbodies posing a threat to humans and the environment. Flooding and sea-level rise can also inundate cesspools causing human waste to leak out, creating a public health concern for communities. – Michael Mezzacapo, University of Hawaiʻi Water Resources Research Center and Hawaiʻi Sea Grant

Movement in Maui
Upcountry Maui was identified as a ‘Priority One’ area in the DOH report of 2017. The upcountry area has 7400 cesspools which pose a ‘significant risk’ to human health due to their impact on drinking water further downslope. At a tense public meeting, the need for a more comprehensive action plan became clear. Residents were worried about the quality of their water, but equally concerned at being hit with a bill for $30,000 for a new treatment unit.

To help with that, Roger Babcock, a professor of Civil and Environmental Engineering and researcher at the Water Resources Research Center at the University of Hawaiʻi at Mānoa is putting together a report for DOH, outlining what technical solutions are available for upcountry Maui and what the estimated cost of those solutions would be. It will include a cost-benefit analysis on various options, from doing nothing, to maximizing nitrogen removal from wastewater.

Babcock notes that, unusually, there are no checks by the county or state on cesspools and septic tanks. “In other states, there are usually management programs, or a permit system in place, so that systems get checked to make sure they are working properly.” That’s missing in Hawaiʻi, resulting in aging systems which can fail and leak raw sewage. “We need something like the car safety check to make sure systems are working,” he said.

Toilet Training
The bottom line is that cesspool problems are complex and require what Kaaumoana calls ‘place-based solutions.’ But radical change is on the horizon with an initiative to reimagine the toilet. The Bill and Melinda Gates Foundation set up a challenge in 2011 to change the way we deal with human waste. They aimed to provide the world’s poorest communities with access to clean toilets and reduce the number of children dying from diseases caused by poor sanitation, but the results of the challenge might well pave the way for a sewage revolution in Hawaiʻi.

Gates says, “The toilet has remained more or less unchanged since its invention. If you could go back in time to the mid-1800s, you’d find flush toilets that work basically the same as the toilet in your home.”

The entrepreneur set ambitious targets. “We asked teams to develop a toilet that would destroy human waste or convert it into a valuable resource such as fuel.” The toilet would have to be cheap (less than five cents a day to operate) and work off the grid. Lastly, “People would have to want to use it—ideally not only in poor countries, but wealthy ones too.” Each team got $400,000 and one year of development time.

Five designs floated to the top. They were:

The Ecosan Waste Treatment System (California Institute of Technology): It uses solar energy to extract clean water from human waste. The water is reused to flush.

The New Generator (University of South Florida): This solar system works with any conventional toilet. Water gets treated with a nano membrane filter. Solids are digested by anaerobic bacteria on one side of the membrane, allowing clean water to flow through, so there is no septic tank that fills up.

The Nano Membrane Toilet (Cranfield University): It has an automated scraper, so can be flushed without water. All waste is burned, while liquid is cleansed through a filter and can be used for watering plants. A family would need to empty the ash weekly.

The HTClean toilet (Helbling & Associates): This system processes flush water, urine, and feces together. Pressure and heat then create safe solids and water, which is filtered for flushing.

The Janicki Firelight Toilet: This self-powered option dries human waste into flakes making it easy to burn. Water is cleaned and recycled for flushing, and the system is self-powered.

Some show real potential for installation in Hawaiian homes since they require minimal maintenance or emptying.

Babcock has looked into these systems and points out that this new generation of toilets do not deal with grey water (wastewater that comes from outlets like showers and dishwashers) so a residential Hawaiian home would still need a treatment tank. He is also concerned about the lifespan of the toilets and potential maintenance issues in our damp climate. He does agree, however, that technology is changing fast. “The good thing is that we’ve got 30 years to figure this out. I’m certain we will find cheaper, better alternatives before the 2050 deadline.”

Thinking Bigger
And when it comes to the problems of towns like Hanalei, there are some bigger solutions in the pipeline, too. The Janicki Omniprocessor turns sewage sludge into clean drinking water, electricity, and pathogen-free ash. The plant boils the sludge and separates water, burning the solids and generating high pressure and high temperature steam. This is diverted to a steam engine to create electricity which powers the processor and can feed the excess energy back into the grid. The end result is perfectly clean drinking water (Bill Gates drank a glass himself and declared it… water!) with electricity for free. There are already plans for the next-generation processor, which will handle sewage for up to 100,000 people. It will be capable of producing up to 86,000 liters of drinking water a day and 250 kW of electricity for the grid.
Kaaumoana thinks that Hanalei could be just the place to test some of this technology. She says, “My slogan for the town is that we are small enough to get it done, but big enough to matter.”

There’s certainly support amongst some of the key decision-makers on the islands. Representative Chris Lee attended the Gates Foundation’s Reinvented Toilet Expo in China last year and saw the future possibilities. “These new technologies offer us the potential to solve our wastewater problems more cost effectively. Some of the units are down to $1,000 each,” he noted. The next step would be a pilot scheme which would demonstrate some of the options in a priority area and establish whether these toilets can address all of the wastewater challenges in Hawaiʻi. The DOH and the Cesspool Conversion Working Group are also looking at how to finance alternative technologies through loans, grants and other incentives.

With cesspool pollution causing human health problems and environmental degradation, Gates’ toilet challenge offers new hope. While Hawaiʻi residents will still need to find a way to deal with gray water and extensive testing is needed to see what systems are appropriate for local situations, new technologies may provide a realistic alternative to cesspools and septic systems at a fraction of the cost. The state has faced sewage management challenges for decades, but somewhere under the rainbow, it might be time to start installing the lua (toilet) of the future.

 

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