Curtain Drains, Washer Lines / Beds & Filters

Cutain Drains

Curtain drains are utilized to detour ground water that flows into the septic system installation area. Normally, curtain drains would be installed around the perimeter to protect the secondary treatment portion of the system such as the lateral field, wetland cell or mound. In detouring this excess water it decreases erosion and prevents unnecessary water from over taxing the system.

Curtain drains average a width of 12 inches and have an average depth of 36 to 48 inches. In Kentucky the curtain drain must maintain the required depth in all parts upslope from the lowest lateral line. The piping installed must be perforated on all sides and be bedded in 2 to 4 inches of leveled trench rock fill material. If the curtain drain is less than 12 inches in width pea gravel must be used, however, for trenches 12 inches or greater approved trench rock can be utilized. All trench fill material must extend within 4 inches from grade.

** Note that other specification may apply and can vary from state to state.

Washer Lines/ Beds

Washer lines / beds are a beneficial element to any wastewater system and are highly recommend by health officials. Washer lines/ beds are installed as a separate system to handle the gray water produced at the site and will normally be located close to the home for easy disbursement, when possible. In Kentucky, gray water is considered only the laundry water. No water from sump pumps, sinks or showers are included. This regulation can vary from state to state. By utilizing a washer line / bed unnecessary water, salt, dyes, bleaches, disinfectants, and other chemicals are diverted from entering the septic tank, where they can hamper the growth and performance of the essential bacteria. In aeration treatment units which are more sensitive than the conventional septic tank, this gray water can destabilize the balance required to operate these types of systems properly. In removing unnecessary excess water, the secondary treatment area such as a lateral field will be less burdened and can handle and treat the effluent disbursed to it more efficiently. Additionally, in Kentucky, a 15% reduction in the amount of lateral field required is given to the homeowner, if a washer line / bed is installed at the site.

Washer lines / beds are installed with the same methods as a lateral line or lateral bed. A trench or bed is dug to specified length or bed size and perforated piping with trench rock or chambers manufactured of polyolefin resins are installed to form the absorption field. In place of a distribution box to control water, a washer box is installed. This washer box acts as a splash plate and lint collector for the gray water that enters. Washer line / beds are installed separately from the lateral field or secondary treatment portion of the septic system.

Filters

Installation of a filter on the outlet of the septic tank will prevent large solids from leaving the septic tank and entering the secondary treatment portion of the wastewater system. This saves money by avoiding costly repairs but additionally protects the property value.

How do you determine the appropriate type and size of filter to use?

A) What type wastewater system will the filter be servicing?
i.e. Commercial / Residential

B) What is the gallons per day ( GPD ) usage for the wastewater system?

C) How often will the filter be pulled and cleaned?

Residential Filters
Residential filters are specifically designed for single family residential applications and will keep large materials out of the lateral field which will clog the lateral lines. In Kentucky, the gallons per day (GPD) are based on 120 gpd per bedroom. If you want to provide a higher degree of filtration for a residential application or a longer period of time between servicing, then you may opt to install a commercial size filter.

A residential filter will not usually require servicing more frequently than once a year. However, if the homeowner allows items in the tank such as grease, plastics, paper towel, cigarette butts, etc., the filter will require more frequent servicing

Commercial / Industry Filters
Commercial filters are specifically designed for apartments, schools, churches, shopping centers, offices and many other multiperson buildings. In some instances where higher amounts of water are disbursed, multiple filters may be installed.

Should the commercial location be a restaurant or food processing site an industrial filter should be utilized to address the additional grease and waste products associated with these type businesses.

Other Topics:
Sewage Protection Program | Engineering & Design for Difficult Sites | Imporve Your System - Practice Water Conservation | Aeration System - Do's & Don'ts | Why Systems Fail

Back to Articles | Top of Page