The Biscayne Times

May 30th
The Toxic World Beneath Your Feet PDF Print E-mail
Written by Erik Bojnansky, BT Senior Writer   
September 2019

Rising seas spell doom for tens of thousands of septic tanks

KSeptic_1risten McLean has a mound on her front lawn. It isn’t part of some gardening fad. It’s a necessity if McLean wants the toilets in her house to keep flushing or the drains in her sinks and bathtub to function.

This past March, the toilets in her 64-year-old El Portal house stopped working. A plumbing and septic company confirmed that the problem was the underground septic tank, which was nearly as old as the house.

Just four days after the tank was serviced, the toilets stopped working again. That’s when McLean knew she was going to “have to take care of this right now,” and purchase a new septic tank.

“We were without use of our showers and our toilets for five weeks,” McLean recalls. “They completely rebuilt the entire system.” That new system cost $12,000 and includes a 900-gallon main septic tank with another 450-gallon tank next to it that holds a pump to push the waste flushed from toilets and drained from sinks and showers and diverts it to an adjacent drain field.

McLean knows why her old septic tank failed after all these years. Such devices have trouble working when they’re surrounded by water. In recent years, the groundwater has risen to just 18 inches below her property, which borders the Little River canal. “The river,” says McLean, a member of El Portal’s sustainability committee, “is literally moving into El Portal.”

And that’s why the new septic tank couldn’t be placed completely underground, as in the past. Instead, the new system had to be installed partially above ground, to create more distance between it and the water table, and then smothered by truckloads of dirt.

McLean isn’t the only homeowner in El Portal’s low-lying Soars River Estates on the north bank of the Little River that’s had to do this. At least four of her neighbors have septic tank mounds on their lawns, too. And she’s heard that two other neighbors are having septic issues as well.

Septic_2Soars River Estates isn’t the only place where septic tanks are drowning, either. A Miami Shores environmental study from last summer noted that septic tanks are failing within that village’s low-lying areas. In nearby Biscayne Shores, a single-family home that serves as a convent for four nuns now has a septic mound on its front lawn. And McLean has seen several mounds in Larchmont, an unincorporated area just south of the Little River.

Nearly all scientists agree that the seas are rising, owing to climate change, and are doing so faster than previously predicted. And as more water seeps into the porous limestone that makes up Florida’s bedrock, more septic tanks will cease to function.

Most properties in Miami-Dade County are hooked up to an elaborate sewer system that is generally more resistant to the effects of sea level rise than septic tanks. However, there are as many as 120,000 residential and commercial properties in the county that still use septic tanks, says Debbie Griner, a resilience manager with the county’s Water and Sewer Department. And according to a November 2018 report prepared by Miami-Dade County and the Florida Department of Health, there may be 58,000 properties with septic tanks in areas of low-elevation that experience periodic failure, usually during storm events. In the future, it will be worse. The same report states that more than 67,000 properties with septic tanks will be compromised by 2040.

At least those are the estimates. James Murley, the county’s chief resilience officer, says he doesn’t have exact figures for the number of properties using septic tanks or how many are actually failing.

“We don’t go in and dig up someone’s yard and find out if there’s a septic tank,” Murley explains to the BT.

Even so, the county has a good idea where many septic tanks are located. Along the Biscayne Corridor, El Portal, Miami Shores, Biscayne Park, Biscayne Shores, North Miami Beach, and Ojus are among the areas where most single-family homes, low-rise apartments, and modest retail buildings use septic tanks.

Septic_3Digging out those septic tanks and replacing them with connections to the county sewer system won’t be cheap. A 2016 county report states it would cost at least $3.3 billion just to hook up 83,000 properties. A chunk of that would be paid by property owners in the form of connection fees and higher utility bills.

But rather than aim for a solution that could price out thousands of people now living in the county, officials are looking at various funding options to replace compromised septic tanks. According to a report prepared by the county’s Water and Sewer Department (WASD) and the Division of Environmental Resources Management (DERM), and set for publication this month, the county will also “identify additional monitoring and research needed to establish priorities for addressing septic tank solutions geographically,” says Jennifer Messemer-Skold, WASD’s public information officer.

Staff will look at other options besides simply replacing septic tanks with sewer lines. Those options may include the utilization of new sewage-treatment inventions, abandoning areas that chronically flood, creating localized sewage-treatment facilities, or just leaving some septic tanks alone.

“It’s a very complex issue,” says Murley, “and septic tanks have been here a very long time.”

Septic tanks don’t just store effluent; they biodegrade it. Under optimal conditions, solid matter sinks to the bottom and liquid effluent flows into perforated pipes that excrete it into the soil -- a drain field -- where it’s consumed by bacteria and purified of fecal matter by the time it seeps into the groundwater. The rest of the sludge accumulates in the tank until it’s pumped out.

This process is disrupted when the water table rises, which compromises both the soil-filtering process and the microbes in the soil. Properties in low-lying areas that aren’t hooked up to sewers can expect their septic tanks to stop working more frequently as the sea rises -- and Biscayne Bay along with it.

When septic tanks stop working, they can become environmental hazards. There must be a layer of soil between a septic tank’s drain field and the water table (state regulations now require two feet); otherwise effluent emanating from the drain field won’t be filtered when it hits the groundwater.

Rachel Silverstein, executive director of the non-profit environmental group Miami Waterkeeper, says that if the initial November 2018 septic tank report is true, nearly half of all septic tanks “are not functioning properly at certain times of the year because the water table is so high and there’s no dry space to properly filter the waste.” Result: tens of thousands of septic tanks are leaking fecal matter into the groundwater.

“Even when septic tanks are working properly, they still create a lot of nutrients,” Silverstein says, referring to nitrates and phosphorus that feed algae. “When nutrients get into the groundwater, they travel into Biscayne Bay, which can create algae blooms.”

Septic_4There have already been massive sea grass die-offs due to the high amount of nutrients being deposited into the bay by leaking sewer pipes, pump stations, fertilized runoff, and septic tanks, Silverstein adds. “We really are teetering on the edge of having some major algae blooms,” she warns.

Yet in spite of these dire warnings, Miami-Dade County continues to allow septic tanks to be installed in areas “where the system is already flooded,” Silverstein asserts. Homes with septic systems so rotted “there’s not even a tank left” are also routinely bought and sold, she states.

To rectify these problems, Silverstein says Miami Waterkeeper is advocating for regular inspections of septic tanks, not allowing new septic tanks in flood-prone areas, and creating a long-term plan in which “we don’t have to rely on septic tanks.”

The problem is that the cost of extending the county’s sewer system, which is already in need of a $12.6 billion overhaul, is often borne by homeowners, says Doug Yoder, WASD’s deputy director.

One alternative to many thousands of new hook-ups to the sewer system would be the creation of smaller treatment facilities that can be operated to serve “a single household or a cluster of homes.” These mini treatment centers could be connected to the drain fields of various septic tanks. “Such things can be less expensive than extending sewers, but they require more direct oversight,” Yoder cautions.

And new technologies are in use, while others are being explored. WASD and DERM officials have been talking to James Englehardt, a professor of environmental engineering at the University of Miami, who leads a UM team that has invented two devices that deal with waste. One of those inventions is called Net-Zero Water, a device that can recycle 100 percent of water that goes down toilets and drains, and purify it for indoor and outdoor use.

In 2013 and 2014, Englehardt says, Net-Zero Water was successfully tested at a UM student dormitory. (The students volunteered for the experiment.) That recycled water was used for showers and brushing teeth, though not for drinking or cooking. But Englehardt insists it can be safely ingested. In fact, he says, he routinely drinks Net-Zero recycled water with no ill effects.

“In theory, we could replace the septic tank system [with Net-Zero Water],” Englehardt tells the BT. “It would be extremely expensive at a single-family-home scale, but remarkably, it would be quite economical with 100 homes per treatment plant.”

Englehardt’s team has invented another device that can be used with septic tanks, employing a process he refers to as electrohydromodulating nutrient recovery. This process pulls nitrates and phosphorous from effluent and turns the leftover product into a commercially viable fertilizer. Other nutrient-recovery systems that produce marketable fertilizers are in place around the nation, notably in Washington, D.C., Chicago, Boston, San Francisco, and in some smaller cities, as well as in Canada and Europe.

Septic_5In the coming months, Englehardt expects to test a unit on a county-designated test home. UM is also negotiating a licensing agreement for the process with AXI International, a Fort Myers engineering company that specializes in making clean fuel filtration systems.

Then there’s the option of encouraging people to move to higher ground by buying residential and commercial properties in flood zones. Yoder says the county has looked at the concept of turning properties that flood into a “water management system” that can absorb the rising tides and provide some protection for land on higher elevations.

This has already been done near the Everglades. Since 1990, using taxpayer money allocated to Miami-Dade County’s Environmentally Endangered Lands program and the Florida Communities Trust, the county has purchased 20,700 acres of wetlands.

Property owners may become more willing to sell as it becomes increasingly impractical to live in low-lying places. “A time is going to come where you won’t be able to get insurance,” Yoder says, “or you won’t be able to afford insurance, even if you can get it.”

In a May 2016 report to the county, the Urban Land Institute suggested turning low-lying portions of the Arch Creek Basin into wetlands, with mangroves, corals, sponges, and oysters that would be used as a natural form of flood control. The Arch Creek basin includes Biscayne Park, a sliver of Miami Shores, a chunk of North Miami, a piece of North Miami Beach, and some unincorporated neighborhoods.

One of those unincorporated neighborhoods within this basin is Biscayne Shores, which lies east of Biscayne Boulevard, roughly from 108th Street to 110th Street. It was hit hard with storm surge generated by Hurricane Irma two years ago. (For more on Irma’s effect on Biscayne Shores, see “The High Cost of Water,” November 2017.)

Yet, even though most of Biscayne Shores is in a flood zone and there is at least one septic tank mound in that neighborhood, this area of single-family homes and low-rise apartments is doing fine, now that the county-run pump stations are functioning, insists Don Bailey Jr., a bayfront homeowner and principal of Don Bailey Flooring.

“The neighborhood is continuing to improve slowly,” he says. “I see 108th Street has had a lot of new homes and renovations, and 109th and 110th streets have new construction going on.”

Bailey adds that his toilets, which are also served by a septic tank, flush fine. As for turning the neighborhood into a flood buffer, Bailey believes it would be far easier and cheaper to supplement the pump system and put in a sewer system than to buy everyone out.

Kristen McLean notes that property values are climbing in El Portal, too, thanks in part to the wave of development that is now flowing through the City of Miami’s Little Haiti neighborhood. But she isn’t sure if that will continue should more unsightly septic mounds appear on residents’ lawns.

McLean notes that El Portal has a state grant to hook up parts of the village to the sewer system, although it doesn’t currently encompass her particular subdivision of Soars River Estates.

While awaiting the arrival of sewers, McLean wouldn’t mind seeing some rules governing the appearance of septic mounds. Or at least some guidelines. As it stands now, all that is required is that the septic tanks be covered with soil and turf, and not with particularly “thirsty” plants, such as trees that could break the system with their roots. “The challenge became, ‘How do we make it not look like a concrete brick?’” she recalls.

So McLean contacted her friend Martin Rocha, a former DERM employee who now works as a high school science teacher and runs a landscaping business on the side. Rocha was able to find a selection of native plants with roots that won’t compromise the septic tank. The resulting landscape is an attractive garden area.

In spite of rising sea levels, McLean doesn’t regret buying a home in Soars River Estates three years ago. An advocate for a clean Little River, McLean, her husband, and two kids now have the flowing waterway just beyond their yard.

As for the future, she thinks the neighborhood will look very different in a few decades as the effects of sea level rise become more apparent.

“What will start to happen is people will raise their houses like they do in the Keys,” McLean says. “We’ll be long gone by that time.”

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