The World Bank is lending the Philippines $275 million to tackle huge volumes of untreated sewage that threaten to swallow the capital Manila, the lender said Wednesday.

The loan would be reinvested by a government bank into Manila Water Co. and Maynilad Water Services projects to boost the two utilities' household wastewater collection and treatment systems, the World Bank said.

World Bank country director Motoo Konishi said the project is part of the lender's broader programme to support the urban renewal of Manila, a metropolis of at least 12 million people that is blighted with huge slums.

Its residents produce about two million cubic metres (500 million gallons) of wastewater a day, of which only 17 percent is treated before being released into Manila Bay, the bank said.

The rest seeps into 30 highly polluted rivers and streams criss-crossing the city and eventually ends up on the bay.

"The health of poor families, especially their young children, suffers the most from lack of proper wastewater treatment facilities and poor sanitation," Konishi said.

Economic losses from poor sanitation add up to an amount equivalent to 1.5 percent of the country's total economic output, Konishi said.