Drought stricken California county looks to nuclear plant desalination plant

California’s San Luis Obispo County board of supervisors has approved a sewage reclamation project that could add treated wastewater to an aquifer and the expansion of a desalination facility at the Diablo Canyon nuclear power plant as emergency water supply options.

Years of drought have reduced South County’s main water source, Lopez Lake, to 29% capacity, shrunk aquifers and made deliveries from the State Water Project pipeline unreliable.

A proposed expansion of Diablo Canyon’s 3.2 Ml/d desalination plant has the potential to produce the most new water – as much as 1,250 Ml a year through expansion of the reverse osmosis facility.

A 10 km pipeline would have to be installed to connect the plant to the Lopez Lake pipeline. A feasibility study is underway.

Deputy public works director, Mark Hutchinson, told local press that the planing project would cost up to US$ 500,000 and construction of the pipeline would cost up to US$ 11 million. He said the county would seek state grants for drought relief to offset the costs.

A sewage reclamation project at Pismo Beach could generate some 800 Ml of treated, recycled wastewater to be injected into groundwater supplies. That project has become a regional one, with other cities in the area collaborating. Construction could begin next year and finish at the end of 2018.

Saltwater intrusion into the Santa Maria groundwater basin since 2009 forced water retailers to reduce their pumping to 30% of their entitlements. Low reservoir levels in Northern California have led to severely limited deliveries from the State Water Project in 2014 and 2015.

The Diablo Canyon desalination facility has been operating at 40 % capacity to meet the power station’s needs. The desalination report identified other opportunities including expansion of other desalination facilities in Morro Bay and Cambria and co-locating new facilities on industrial sites.