SAN FRANCISCO (KGO) --Through San Francisco's largest waste treatment facility flows 80 percent of the city's sewage, but it is constantly in need of repairs. Recently, crews worked on emergency repairs on the roofs to keep the odor down and the sewers running a little longer.
"1.8 million gallons of sludge, in each of the 10 digesters, and were 30 feet away from people's homes," Plant Superintendent George Engle said.
"This facility was built in 1952, which means it has significantly aged, it's worn, it's taken its toll and we need to rebuild the entire system," Assistant General Manager for Infrastructure for the San Francisco Public Utilities Commission Emilio Cruz said. "It's been a testament to the operation staff here keeping this plant alive," he added.
Cruz showed ABC7 News around the massive, aging, southeast sewage treatment plant. It's the largest in the city and long overdue for an upgrade.
"What we are looking at is rebuilding the major components of the plant, the headworks, the biosolids and some of the treatment plants within. As a result, we need to build an effectively new treatment plant here," Cruz said.
On Tuesday, Cruz was expected to present alternatives to the commission.
"We've looked all over the world, we are actually looking at bringing in technology that does not exist in the United States, but has been successful in Europe for a decade," Cruz said.
"Before we go under construction, we want to test all the equipment in a pilot phase. So this is pilot installations to make sure the equipment that we get for the long term is sufficient," Engle said.
Smaller versions of that technology are already being tested out as part of a $2 billion planned upgrade of the facility. It will be paid for by ratepayers.
"We have digesters that we can feed different concentrations into and see results. We're doing thermal hydrolysis over here, we're going ammonia removal behind us," Engle said.
This facility has operated 24 hours a day since it opened more than a half century ago. It's a maze of pipes, tunnels, tubs and cisterns that treat 57 million gallons of waste per day. When it rains, that jumps to 250 million gallons.
"This is our one chance to fix the plant, to do it right and to make sure we have a legacy for generations to come," Cruz said.
In late 2012, The San Francisco Public Utilities Commission began planning to replace the existing treatment plant. The big challenge for engineers will be keeping everything flowing while they do it.
"We're probably looking at investing over $50 million in this plant just to keep it running through the end of construction of the new plant.
If all goes smoothly, construction on the new plant will begin by 2017.
Written and Produced by Ken Miguel