Work is beginning on replacing a mile of main sewer line near the Sonoma County Sanitation District plant, where a sinkhole developed last year when the aging pipe collapsed.

The work includes a second pipe that will carry recycled wastewater that will be used for agricultural irrigation, according to Brad Sherwood, a spokesman for the Sonoma County Water Agency, which runs the sewer district.

The 50-year-old sewage pipe is part of an aging and leaky sewer system which can overflow during the wet months and cause sewage spills.

The project includes putting in a mile of sewer line and the recycled water line on private property adjacent to the sewer plant on Eighth Street East outside Sonoma.

The cost is $2.3 million, with federal recovery act money covering the $500,000 cost for the recycled water line.

The work is expected to be completed by November.

-- Bob Norberg