The largest municipal water agencies in the state – responsible for Los Angeles and Southern California – have set visionary goals which aim to: recycle up to 100% of wastewater, capture more stormwater, recharge more groundwater and conserve more water. One initiative has been offering ratepayers up to $3 per square foot to replace their grassy lawns with drought tolerant plants. They have also implemented massive public education programs and regulations to modify behaviour regarding water usage (water conservation, low-flow toilets, low-flow shower heads, reducing outdoor landscape watering). Since 1990, the state has successfully reduced water use per capita by 20-30%.
In Southern California, WSP is working with Arcadis and Balfour Beatty to build a new wastewater recycling plant that will treat 10 million gallons per day (438 litres per second) and recharge a local groundwater drinking aquifer. In San Diego meanwhile, there is a multi-billion-dollar, multi-year indirect potable reuse project in progress that will use advanced treatment technology to purify 30 million gallons per day (135 million litres per day) of recycled water.
LA Sanitation runs a recycled water filling station outside one of its water reclamation plants. The disinfected water here can be collected by residents for free and used in place of potable water for landscaping.
Sweden: Anna Dahlman-Petri, Senior Consultant in Water at WSP
In Sweden we historically have had a lot of fresh water and few historical issues with supply. However, for the last several years in a row, we have experienced drought. With climate change this is likely to become an increasing challenge.
Like the UK, we have also experienced flooding issues, like a cloudburst event in central Stockholm, which affected city-centre properties and as a result, was very high profile.
In locations like Stockholm, where the population is rising, addressing these challenges within existing capacity is increasingly an issue.
We’ve started to look at new technologies and solutions that can increase supply – like desalination, combined with behaviour change campaigns. We’re using sustainable urban drainage schemes to help mitigate extreme rainfall.
At a consumer level, we need to address similar challenges to the UK: cost isn’t a strong motivator of change. As we move to a climate of greater extremes, the public need to be more aware of potential supply issues and the work that goes into ensuring continuity of supply.