Fly-ash is a hazardous environmental byproduct from coal-fired electric power generation and industrial boilers.
For decades, utilities have disposed of coal ash dangerously, dumping it in unlined ponds and landfills where the toxins leak into groundwater. Some estimates state there are over 3 billion tons of legacy and “fresh” fly-ash waste in the U.S. alone. Many landfills and collection ponds are near large cities.
According to industry’s own data, 94% of the coal ash ponds in the United States are unlined. Unlined ponds are contaminating groundwater with toxins above levels that the U.S. Environmental Protection Agency deems safe for drinking water.
Legal and technical experts from Earthjustice, the Environmental Integrity Project, and partner organizations located and analyzed the data disclosures from utilities that report groundwater monitoring data and found that 91% of these plants are contaminating groundwater with toxic substances at levels exceeding federal safe standards.
AquiPor’s permeable concrete can be used to sequester various harmful industrial waste by combining these materials with our catalytic binder. One such waste material we have been successfully testing in our mix designs is fly ash.
There are environmental and economic advantages to recycling this waste back into our concrete, but in addition to that, it creates some emerging properties that are very compelling for our permeable technology.
How about that...taking care of industrial waste that is contaminating groundwater and putting it into new, useful permeable material that can help improve groundwater and freshwater in our cities?!
It’s nice to see that the concept of “sponge cities” is starting to go mainstream. We’ve long believed that one of the most practical ways to improve urban water quality, facilitate sustainable water infrastructure, and generally make our cities more resilient in the face of climate change is to simply add more permeable surface area in our cities.
Wet regions and drought-stricken areas alike can benefit from a “spongier” approach to physical infrastructure. As the atmosphere warms, it holds more water, which can then result in flashier and quicker rain events. The challenge with these sudden rain bursts is that outdated municipal water infrastructure is easily overwhelmed. This leads to extreme flooding and polluted waterways.
Undoubtedly, there have been unintended consequences to urbanization. The amount of impervious surfaces - in the form of streets, sidewalks, alleyways, and rooftops - is one of them. Land that once absorbed rainfall, returning it to the natural water cycle, is now caked over with pavement. Rainfall now hits those surfaces and runs off to gutters and storm drains, picking up every pollutant and toxin in its path. This polluted runoff is expensive to treat at wastewater plants and every drop of water that doesn’t naturally re-enter the water cycle creates another unintended consequence that is even more dire - aquifer depletion.
At AquiPor, we’ve always thought of stormwater as an asset rather than a liability of waste. Large, quick rainfall can become very valuable for cities if they design their physical infrastructure in ways that can utilize it. There’s no better way to do that than getting it back into the ground naturally through porous concrete and other green infrastructure approaches.
If you’ve been following AquiPor for even a short amount of time, you know that we are developing a new type of permeable concrete that would help alleviate stormwater pollution in cities, and we’re really excited about that. It’s not every day you invent a technology that could not only make life better for people in cities but can also directly help make our communities more resilient to the impacts of climate change.
In short, our permeable concrete can help ease the pressure on already overused sewage systems and reduce pollution in the environment by providing a better way to handle rainwater and snow runoff. Instead of allowing polluted stormwater to run off of paved surfaces and into storm drains, our permeable pavers will allow this water to flow down through the material and into subsurface layers before naturally recharging groundwater.
There are many applications for our permeable concrete, and we thought it would be fun to share some ideas we have that you might not have thought of. Here are 5 possible applications of our permeable concrete:
1. Swimming pools: Not the actual swimming pools, that would be kind of silly to have porous material in your pool, but imagine that you have permeable pavers surrounding the pool. Excess water gets drained from around the pool, making it a safer place for your kids. Now, instead of yelling at your kids to “stop running around the pool!”, you can yell “kids, run and get me another beer!”. Honestly though, having less water around makes it less slick and therefore a lot safer for those you love. Just imagine!
2. Parking lots: You may not even notice it, but those random grassy swales in retail and commercial parking lots are actually there to deal with stormwater runoff. Instead of bulky, space consuming swales or stormwater ponds, AquiPor permeable pavers can take their place to manage stormwater without taking up all that usable space! Btw, did you know that 5.5% of all developed land in the U.S. is made up of impervious parking lots?! This is a problem we know can be reversed!
3. Sidewalk Panels: There are millions of miles of sidewalks throughout the U.S. and almost all of them are impermeable. What better way to manage stormwater from the street than to direct it to permeable sidewalks and manage it right there?! Now of course, these systems need to be designed and engineered to be structurally sound and to prevent road settling but we’ve considered that too. Our “steady-state”, porous detention tanks go underneath our permeable sidewalk panels and regulate how fast stormwater goes back into the ground based on the natural hydrology of those soils. As part of a fully engineered design, we can literally turn neighborhoods into stormwater infiltration corridors. Neat huh?
4. Bike lanes and walking paths: As more and more cities embrace micro-mobility and pedestrian friendly neighborhoods, why not turn the designated bike lanes and pathways in cities into permeable surfaces? Any opportunity to transform impervious pavement into permeable surfaces not only helps with stormwater and flooding issues, but it’s also known that permeable paving can help eliminate urban heat island. Pedestrian friendly + stormwater management + elimination of urban heat island = WIN WIN WIN!
5. Driveways and residential patios: Using permeable pavers in a residential driveway and / or patio can help alleviate all manner of groundwater and stormwater runoff issues, while also safeguarding local water quality by protecting against the infiltration of pollutants. In cold climates, electric or hydronic heating systems in conjunction with a well-designed permeable paver system can not only eliminate snow and ice, but it can get that precipitation back into the ground naturally. Of course, these system designs cost more but it goes to show you what’s possible with permeable concrete pavers!
At AquiPor, we’re hard at work developing our technology to meet the standards necessary for each and every one of these applications. What else haven’t we thought of?! Get in touch with us and let us know!
With climate change ever-present, it’s time to consider the value of stormwater and treat it like the freshwater asset that it is.
Even in the drought-ridden American West, climate change doesn’t necessarily reduce the amount of water an area receives, but it definitely has changed how, when, and in what form it arrives. This means more volatile precipitation, less snowpack, more flooding, higher temperatures, and shorter wet seasons.
The impact that this is having on our watersheds is alarming. All of the water that we consume comes from a watershed. Watersheds consist of two distinct parts: surface waters - which are streams, rivers, and lakes - and groundwater, which is stored in underground aquifers.
Most areas, at least in the West, rely heavily on groundwater. The need to replenish these underground stores is critical, and every drop of stormwater that becomes runoff instead of seeping back into the ground is a missed opportunity.
In most U.S. cities, where upward of 40% of the urban landscape is paved over with impervious surfaces, huge volumes of runoff are generated each time it rains. There is an enormous opportunity for cities to adapt to the new normal of climate change by turning impervious surfaces permeable. In this era of flashier rain events, where wet weather events can be extreme, volatile, and quick, cities can become more resilient by prioritizing the use of permeable paving and green infrastructure. Not only can it help mitigate urban flooding and runoff pollution, but it can readily get much needed precipitation back into the ground.
The majority of urban surface area in the U.S. consists of concrete, asphalt, and other pavements that are impermeable to water. There are unintended consequences for the millions of miles of collective streets, sidewalks, parking lots, and rooftops that cover our cities.
It’s estimated that over 10 TRILLION GALLONS of untreated stormwater, wastewater, and sewage gets discharged into clean water bodies every year. Traditional concrete and asphalt surfaces have a major role to play in this.
When it rains, stormwater that should naturally soak into soils and recharge groundwater instead becomes polluted runoff as soon as it hits the pavement. In some regions that are experiencing larger and more sudden flashes of rain, the issue has evolved from one of stormwater pollution into one of urban flooding.
Interlocking “gap” concrete pavers are prone to collecting debris within the gaps.
On the other end of the spectrum - in drought-ridden regions - when it actually does rain, every drop of rain that turns into runoff is wasted. Permeable pavement’s role in solving these issues is now undeniable.
So what exactly is Permeable Pavement?
In the most basic sense, permeable pavement is a type of paved surface that is designed to allow rainwater to pass through it and back into the ground naturally. It seems like a no-brainer, but as great as the concept might be, the market for permeable pavement remains nascent due to a technology lag. Solutions such as porous asphalt, pervious concrete, and interlocking “gapped” pavers have been around for decades with very little innovation.
More specifically, the lack of durability and a propensity to quickly clog up from debris has limited the real world potential for these products. Expensive maintenance and replacement costs haven’t helped, and the irony of portland cement-based permeable pavements should not be lost on us. The cement industry is responsible for 8% of global CO2 emissions. Elevated greenhouse gasses are amplifying climate change which is delivering more extreme weather. In other words, the very technologies meant to help cities adapt to climate change are in part contributing to it.
This pervious concrete installation became impervious from clogging and moss growth.
Leaping Technology Forward
Despite all of this, permeable pavement should still be a key component of stormwater infrastructure moving forward, just not as it has existed in the past. Fortunately, new technologies are being developed that are resistant to clogging, as durable as normal concrete, and made with new types of “cement” that are environmentally friendly. At AquiPor, we’ve been fortunate to have a front row seat as the technology has evolved.
In conjunction with reliable engineering, good hydrologic analysis, and an accounting of the capacity of the underlying soils to accept stormwater at a given rate, this type of material can be implemented into a permeable system design for full infiltration, partial infiltration, or even full attenuation where stormwater reuse is desired.
Hard surfaces are very useful in our cities. Unfortunately, as they exist today they also contributed significantly to urban water issues. But with the right permeable technology and good engineering, they can be transformed to help improve the sustainability and quality of our natural water systems.
The current state of stormwater in the United States presents a unique challenge for design professionals of the present and future. The increased flooding and pollution problems associated with our changing weather patterns has become more noticeable with the passing of each season. The question now really is how bad will these problems become as the climate continues to change? For starters, recent studies indicate stormwater infrastructure built in the last 50 years was done so with data that did not account for climate change. In addition, infrastructure in 43 states are currently designed with data collected no sooner than 2015. Alarming for communities in the Pacific Northwest, rainfall records representing industry design storms date all the way back to 1973. The issues will continue to accelerate as long as The National Oceanic and Atmospheric Administration (NOAA) Atlas 14, which provides the data that determines design storm criteria, looks at the past and not the future. But even with the most up-to-date rainfall information, climate scientists warn that infrastructure is still likely to fail. The growing awareness behind these issues has brought forth $1.4 billion in direct federal funding over 5 years to the EPA Sewer Overflow & Stormwater Reuse Municipal Grant Program, reflecting only a small portion of an infrastructure bill that will directly impact stormwater improvement projects across the nation. The journey to bridge an $8 billion stormwater funding gap is now underway.
To help ease the fragmented planning efforts across the US, amendments to the Clean Water Act continue to legislate integrated planning, which identifies efficiency from separate wastewater and stormwater programs to best prioritize capital investments while achieving human health and water quality objectives. This holistic approach to planning builds community engagement, aligns objectives, and emphasizes a preparedness for change. The is a total of 30 integrated plans developed throughout the United States, a number expected to grow significantly through the decade.
Since 2015, the AquiPor team has recognized green infrastructure (GI) as a critical component to integrated planning efforts and are pleased to see this reflected in policy. Having said that, the current definition of GI as presented in the Clean Water Act falls short of incorporating the elements of integrated planning. GI is currently defined as "a range of measures that use plant or soil systems, permeable pavement or other permeable surfaces or substrates, stormwater harvest and reuse, or landscaping to store, infiltrate, or evapotranspirate stormwater and reduce flows to sewer systems or to surface waters." Defining green infrastructure simply by its performance characteristics detracts from the overall value of integrated planning. We aren't the only ones that feel this way. A recent study by The Frontiers of Ecology and the Environment reviewed 122 plans from 20 US cities, finding that city planning often fails to explicitly define green infrastructure, but when it does, stormwater concepts of GI are much more prevalent than landscape or integrative concepts. When defined, functions of GI are primarily hydrological. More functional diversity was found in landscape and integrative definitions of GI. In addition, stormwater concepts surrounding GI engage in greenwashing. The study calls for a broadened definition, one that focuses on the relations between ecological and built infrastructure systems to facilitate the production of social benefits. The review goes on to suggest the following definition : “A system of interconnected ecosystems, ecological–technological hybrids, and built infrastructures providing contextual social, environmental, and technological functions and benefits. As a planning concept, GI brings attention to how diverse types of urban ecosystems and built infrastructures function in relation to one another to meet socially negotiated goals”. We believe this broadened definition of GI incorporates the elements of integrated planning far greater than the one that currently sits in legislation.
AquiPors ecological-technological approach to stormwater management helps to redefine GI by incorporating current infrastructure improvement needs and applying them into a singular retrofit design. By simply modernizing our nation's sidewalks, we can re-imagine transportation by evolving complete street concepts, utilize existing gray infrastructure as real estate for a utility housing corridor, and decentralize the basic needs of our communities with a combination of ecological and built systems intended to thrive in the face of a changing climate. Resilient infrastructure requires a new and innovative approach for tomorrow, and AquiPor is excited to meet this moment.