One of the most expensive infrastructure projects the city-parish has ever undertaken is nearing completion after more than five years of construction.

It’s the kind of project that lacks the glamour and constituent appreciation of a new road, but city-parish officials will tell you that it’s more important.

The expansion and upgrade of the South Waste Water Treatment Plant on Gardere Lane, when all is said and done, will cost about $250 million. It is the cornerstone project of the parish’s $1.5 billion, federally mandated sewer system overhaul.

The improvements at the massive sewer plant will allow for the Central Waste Water Treatment Plant, off River Road, to eventually be closed, leaving the south plant and the North Baton Rouge Waste Water Treatment Plant located near Southern University.

The sewer plant, scheduled to be fully operational by December, will be capable of processing up to 205 million gallons of wastewater every day. That compares with 120 million gallons before the expansion.

The plant also has four massive reserve tanks, some the size of the Pete Maravich Assembly Center, which hold an additional 168 million gallons of wastewater when the plant is inundated by strong storms with heavy rains.

The sewer plant, built about 50 years ago, has been undersized and in need of repairs. Baton Rouge streets and homes have been plagued for years with sewage backups when heavy rains flood the undersized sewer system.

It will ultimately be responsible for cleaning the vast majority of the parish’s wastewater before it is released back into the Mississippi River. The North Baton Rouge plant has a capacity of about 40 million gallons and processes about 8 million gallons a day.

The North Baton Rouge treatment plant will undergo $50 million in upgrades and improvements. However, it will not be expanded because it already has ample capacity for the area it serves.

Construction on the south plant started in April 2009. It was broken up into three phases, and officials say they are in the “home stretch” of completing it.

The major construction is finished, and what’s left is finishing the outfall, which is where the cleaned wastewater is piped past the new L’Auberge Casino, over the levee and into the Mississippi River.

“I wouldn’t call it drinking water, but it’s cleaner than the water that’s in the Mississippi River now,” said Bryan Harmon, interim director of Public Works for the city-parish.

The Central water plant will eventually be shut down in 2016, said Joseph Young, the deputy program manager of the Baton Rouge Sanitary Sewer Overflow program. After the South plant is completed, it will take additional construction to redirect the sewer lines from the Central plant to the plant on Gardere Lane.

Young said the city will enjoy cost savings by shutting down one of its three plants, because of lower labor and maintenance costs. The Central plant is also dated and would require expensive upgrades if it was to stay in use.

Having one less plant also means there’s one less place where treated sewer water is being returned to the Mississippi River. That will save the city on costs for environmental monitoring at that location to ensure water quality meets federal cleanliness standards.

On Tuesday, a group of about 80 water and wastewater professionals from across the country toured the facility. They traveled to Baton Rouge from New Orleans, where they were attending the Water Environment Federation’s annual Technical Exhibition and Conference.

They got to view the sophisticated filtration systems, a new electronic operating system that provides remote control of the system, massive odor control towers and five huge new generators that each hold 10,000 gallons of fuel.

It became apparent that the generators were necessary after Hurricane Gustav rolled through Baton Rouge in 2008, knocking out power for several days, leaving the sewer plants unable to process and move accumulating rain and wastewater.

The Sanitary Sewer Overflow program has a total price tag of $1.5 billion, a number that has crept up over the past few years. The program includes 110 construction projects that mostly involve fixing sewer lines and adding larger lines to increase capacity. The underground sewer lines were previously crumbling from age and leaking untreated wastewater.

In 2002, Baton Rouge entered into a federal consent decree by the U.S. Environmental Protection Agency to fix the sewer system. The deadline, which has since been extended, for all projects is December 2018.

By the end of the year, about 60 of the construction projects will have been finished and about $1 billion has been obligated.

Follow Rebekah Allen on Twitter, @rebekahallen. For more coverage of city-parish government, follow City Hall Buzz blog at .