A US engineering firm was prized Sunday for its efforts to treat used water and turn it back into drinking quality.

Employee-owned CH2M received the Stockholm Industry Water Award for developing methods for the reuse of water and raising awareness of the benefits of recycling wastewater, the Stockholm International Water Institute (SIWI) said in a press release.

"(CH2M is) an engineering company that has gone beyond their technical roots to work for a better world. We must focus on the water we have, and make sure we use it well and can use it again, and again," Peter Forssman, SIWI's chairman, said in a statement.

CH2M - which serves government and business clients within areas such as transportation, energy and water management - received the award both for its water-recycling work and for educational efforts designed to convince customers to put "purified sewage water back in household pipes," the policy institute said.

The prize, awarded each year to businesses for their involvement in water management, was established in 2000 by SIWI, Sweden's Royal Academy of Engineering Sciences and the World Business Council for Sustainable Development.