Public Works and Wastewater Frequently Asked Questions

  • Will the parish need to rebuild or replace any of the current wastewater plants?

    The Wastewater Department is constantly making repairs to the system, and the parish president and council have been providing monies to do so.

    The 20-year life expectancy of the plants is being extended through a good maintenance program. But at some point in the future, the plants will have to be replaced or upgraded (maintenance cost continually increase with age). The Oxidation Pond will need to be dredged at some time in the future.

  • Does the wastewater plant discharge wastewater into the wetlands?

    The Luling Oxidation Pond discharges treated wastewater into the wetlands south of Luling. The Hahnville and Destrehan Wastewater Treatment Plants discharge into the Mississippi River.

    The parish has three sewer treatment facilities: One in Hahnville (2.3 million gallons per day), one in Destrehan (6 million gallons per day) and the Luling Oxidation Pond (3.2 million gallons per day), which has been in operation since the mid-1960s. All the wastewater from I-310 east goes to the Oxidation Pond. It is a faculative pond, meaning the wastewater goes into one area and then through a series of separating curtains and eventually to a discharge point.

    During that time, which takes 20 to 30 days, there is a lot of biological activity going on. Bacteria eat the organics and sediment from the wastewater and the remaining non-organics settle to the bottom.

    The water then goes through disinfection to make it suitable for discharge into the wetlands.

    The Louisiana Department of Environmental Quality has set the limits for wetland assimilation, and this program helps reclaim wetlands. The nutrients in the effluent helps the local vegetation. So far it has been very successful in promoting vegetative growth in the area. The area is continually monitored. We are also in the process of verifying carbon credits within the discharge area.

    Overall, the cost of treating wastewater through an oxidation pond is cheaper than treating it through a mechanical plant.
  • What is a backflow preventer?

    Another name for a backflow preventer is also a 'check valve'. This device stops sewerage flow from backing up into a home. Most older houses do not have backflow preventers, but from the 1980s until now, they have been required in new construction.

    If your home has a backflow preventer, there should be a 4-inch cleanout no more than four feet from the slab, and another 6-inch cleanout near the street.
  • What is a lift station and how does it work?

    A lift station consists of a well and two or more pumps that collect sewerage and lift it to a higher elevation. A pump station then pumps the collected sewage and sends it to the treatment facility. Sewerage is gravity fed into a main line, and those lines will be pumped at the lift station from that location to another location, and then downstream to the treatment plant. 

    The parish operates over 300 lift/pump stations.

  • What substances should never go down the drain?

    Oil and grease is very detrimental to the sewer system. Frying pans and pots of oil should NEVER be put down the garbage disposal. These substances clog up the pipes and cause plugged lines. Grease solidifies within the sewer system and causes dams.

    Never put any harmful chemicals down the drain, nor any plastics or metals. The only thing flushed down the toilet should be tissues; never paper towels. All substances put down the drain should be biodegradable.
  • Will the parish install subsurface drainage on my property?

    Implementing Subsurface Drainage

    Correctly implementing subsurface drainage in an area serviced by open ditches requires more than simply installing a minimum-sized culvert. A proper analysis is necessary to determine what effects introducing subsurface drainage will have on the surrounding area, not simply one parcel. The volume of water a ditch conveys during and following rainfall must be addressed. This requires consideration of the characteristics of not only the proposed site but upstream and downstream factors as well. This information cannot be obtained by visiting one residence and employing sound judgment. It is possible and likely that areas miles away will be affected.

    Existing Driveway Culverts
    Existing driveways throughout the parish present a problem for the installation of subsurface drainage. It is not uncommon for a driveway culvert to be inadequately sized and sloped. To correctly implement subsurface drainage, installation must meet the elevation of any existing culverts and provide for appropriate flow. These requirements can be contradictory when a system is constructed in a piecemeal fashion.

    Existing Subsurface Drainage
    Subsurface drainage installed prior to 2008 has created some problems. Many of the structures are not graded properly, and some are partially or completely filled with debris, substantially damaged or continually hold water. Adding to a problematic system without addressing the existing problems will cause additional system failures.

    Available Capacity
    As Figure 1 demonstrates, installation of a pipe into an existing ditch may reduce both capacity and storage of the system. This further demonstrates why a systematic approach to drainage is necessary as opposed to intermittent installation.

    The parish has obtained legal guidance stating that it may not expend funds on individual aesthetic improvements to private property. This includes the cost of hiring engineers or using parish employees to size individual culverts to replace existing drainage, as well as the actual installation of said culverts. Unless the parish is undertaking an improvement that will result in the betterment of the parish, such as improving the drainage for an entire street or basin or rectifying a safety issue, such as a roadway that is unsafe due to steep shoulder slopes, the resident must undertake the cost to both design and install the aesthetic improvement in question. “St. Charles Parish is prohibited from donating public funds for the engineering of subsurface drainage for the sole benefit of certain private landowners. St. Charles Parish may, however, fund these engineering costs if such an expenditure will be in the best interest of the parish as a whole and not just the private landowners who may receive an indirect benefit of the engineering services.” – Attorney General of Louisiana, James Caldwell

    The improper installation of subsurface drainage can worsen parishwide systematic drainage issues and reduce storage capacity. The funds required to properly design and install a subsurface drainage system makes it a costly undertaking. Because a drainage system needs to be designed as a whole, and not just at a single residence, the design needs to encompass an entire street, if not a large area. Additionally, the cost to maintain a closed system is higher than the cost to maintain an open ditch sytem. An open ditch can be redug relatively quickly and cheaply, while a culvert must be cleaned out with specialized equipment. Finally, the parish cannot legally expend funds on subsurface drainage for aesthetic purposes as described by the attorney general of Louisiana, James D. Caldwell.

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