Water use can be more efficient, speakers at a symposium in California said May 23 — not just in terms of conservation, but in terms of doing more work for society.
MOUNTAIN VIEW, Calif. — Water conservation is about a whole lot more than saving water — or it could be. Emerging technology is aimed at bringing together water conservation with the worlds of electric power generation, flood prevention, pollution control, data collection and infrastructure planning in a very complete sense.
At the Spring Water Symposium on May 23, water experts in drought-stricken California spoke out about some promising technologies and concepts that can accomplish multiple goals at once, all centered around saving water.
And along the theme of connecting multiple systems, they pointed out that water does, in fact, already connect with myriad aspects of society. For example, the electric power sector is needed to pump water across the state, and developers must work with water requirements when building.
Basically, water affects the entire economy. And at the symposium, the experts explored the possibility that water conservation might not just be a temporary wish of regulators, but a long-term necessity. After all, a monster El Niño this winter wasn’t enough to break the state’s historically long drought.
“A 2013 study estimated that water shortages of 10 to 30 percent would result in a decrease in economic activity of $883 million to more than $10 billion in Santa Clara County alone,” said Barbara Keegan, chair of the Santa Clara Valley Water District Board, at the symposium. “So finding solutions … is obviously very critical.”
These are three technologies the speakers discussed at the event that could help change the way government manages water.
The question is driving the adoption of onsite reuse, which got a big boost last year when San Francisco adopted a city ordinance mandating the technology in all new buildings larger than 250,000 square feet. The idea is to capture water that’s been used once, treat it to sub-potable standards, and then reuse it for purposes that don’t require drinking-grade water. Aside from toilet flushing and irrigation, that can also include using the stuff to cool a building and avoid using a costly air conditioning unit.
The impact at the single-building level can be huge — depending on the type of building and reuse system, the San Francisco Public Utilities Commission (SFPUC) has found reductions of potable water use from 50 to 95 percent. That’s spurred interest in spreading the practice; SFPUC is also working with government entities across the country to develop regulations enabling the speedier deployment of onsite reuse.
But there’s more to be done with water than simply reusing it. At the Codiga Resource Recovery Center at Stanford University, researchers think of water a little differently.
“We want to move past the paradigm of pollution control to a paradigm, really a mindset, of mining,” said Sebastien Tilmans, Codiga’s director of operations. “You go to an iron mine, you’re not getting pure iron out of the ground. You’re getting iron ore, and you need to remove those impurities before you have a valuable commodity. Wastewater’s the same way. Wastewater is water, it’s energy, nutrients, materials and information. It just happens to have impurities, it has salts, it has pathogens and it has … trace organics.”
There are a lot of potential uses for all of the things that one finds in wastewater. Urine can be broken down into nitrogen and phosphorous — ingredients for fertilizer. By running sewage through anaerobic digesters, one can create renewable energy. And as for information, there are people who see sewage as a potential tool for monitoring pathogens that can illustrate how diseases spread.
However, the systems are not widely used and might be costly. Newsha Ajami, director of urban water policy at Stanford’s Water in the West program, said at the symposium that the price point of water might not make onsite reuse systems very economical for the time being.
“When you talk about recycled water or stormwater capture or onsite reuse, these are generated water. So on top of the fact that you have to clean up the water and put it in the system and distribute it, you actually have to pay for generating it,” Ajami said. “So you add to the cost … there’s a very big cost associated with building this kind of infrastructure, and there’s a big cost associated with operating and maintaining it, and right now we do not have a high enough demand to maintain these systems continuously.”
Ask Houston — flooding is a big problem for many urban areas.
Much of that is because of the shielding effect pavement and asphalt have on the natural landscape. Where rain used to sink into the ground, it now collects in pools and runs along dirty streets until it finds a gutter or ground. Along the way it can pick up all manner of pollutants, from copper to pathogens, and carry them to nearby rivers, bays or lakes where they can wreak environmental havoc.
Cue the calls for developers to limit runoff and water pollution when they build new projects.
There are a few solutions they can look to, and that government can retrofit, to solve both problems at once. Collectively, people often refer to them as green infrastructure.
The concept can be as simple as sloping a grass-covered patch of ground or as expansive as replacing an entire parking lot. By designing for rain water, cities can direct water more quickly to ground and plants that can drink it up and let it sink into the dirt, either slowing the advance of the water to the gutter or preventing it entirely.
There’s also pervious pavement, which has a loose-packed structure allowing water to seep easily through.
The concept might see significant interest from government agencies in coming years, with calls escalating for protection from runoff pollution in places like the Chesapeake Bay. On top of that, a group of governments and nonprofit entities in the Calumet region of southern Illinois banded together last year to design materials helping public entities to plan out green infrastructure projects.
“You go on the [Pacific Gas & Electric] website and you see a graph comparing your household energy use with that of similar households. You can see where you rank in terms of efficiency. Water agencies have been implementing similar reports on the water side and have seen great results,” said Andree Johnson, a senior water resources engineer at the Bay Area Water Supply and Conservation Agency. “Households that have been receiving these reports comparing their use to their neighbors have achieved 5 percent more savings during the drought than those households within the same cities that have not received the reports.”
Of course, technology and infrastructure can help build knowledge as well. Smart water meters can give information on how much water a house is using down to 15-minute increments, which means the customer and the water manager both have a lot more insight into how they might go about reducing water use.
“[A smart meter installation] enables them to communicate more frequently with customers and catch problems early — for example, leak detection,” Johnson said. “Previously a customer with a leaking toilet might not realize that anything was wrong until two months after the leak started when they get a massive water bill.”
On top of that, better data collection and analysis means that agencies responsible for managing water can paint a more complete picture of where they should focus their water-saving efforts, as well as what the true impacts of previous efforts were.
Which means a more effective and efficient use of dollars set aside for water conservation.
“We need to really look at what our possibilities are, what the potential solutions that we have are, and strategize on what would be the best portfolio for us as a region, and that goes back to … data management, being able to look at what we have, smart data, being able to understand what the demand is, what’s the trend in water demand and do we really, really need to build large infrastructure to meet future demand?” Ajami said. “Because so far what we have seen is demand keeps dropping, but we are still talking about large infrastructure.”