Two Stanford University engineers looked at stormwater runoff capture and wastewater recycling in the development of AquaCharge, a new software tool aimed at helping utilities find cost-effective ways to replenish aquifers.

“The ideas of recycling wastewater and capturing stormwater are not new,” says Richard Luthy, one of the engineers behind the software. “What’s new here is to think about how to combine what had been separate systems into a single approach to recharge groundwater.”

Luthy says the tradeoffs of each approach typically cause utilities to pursue one option or the other, rather than a combination of both. Collecting stormwater requires large spreading basins in order to take full advantage of the wet season and not all water agencies have the land available for that approach. Using recycled wastewater to recharge aquifers requires its own separate piping system, a cost not all utilities can handle, so a lot of recycled wastewater ends up being discharged into rivers and other water bodies. But using both approaches is possible, says Luthy, such as in Orange County, California, where recycled wastewater is pumped into spreading basins, eventually percolating back into underground aquifers.

AquaCharge looks at how others can accomplish something similar within whatever existing constraints there may be for their area. It factors in the availability of spreading basins and stormwater supplies, the recycled water production potential, and options for installing pipelines to develop an approach that will be both effective and efficient for a particular utility.

“Our method not only allows you to think about a new kind of hybrid water replenishment system,” says Jonathan Bradshaw, the other engineer behind AquaCharge. “It also helps determine what sort of system will meet a city’s goals at the lowest cost.”

Source: Stanford University