This service provides an inspection of the in ground sewage system. The inspection is conducted to PSMA protocol. The inspection includes the layout and location of the components, a water / dye test of the system, The evaluation of pumps and alarms, if installed and a field check to determine if blowouts or seepage have or are occurring.
Systems are separated into three categories
- Sand Mounds With Tanks, Pumps & Alarms
- Leach fields With Tank & laterals
- Spray Irrigation Systems
Types Of Septic Systems
The following are descriptions of the various types of septic systems, according to the U.S. Environmental Protection Agency.
Conventional Septic System – Consists of a settling or septic tank and a soil absorption field. The traditional system accepts both greywater (wastewater from showers, sinks, and laundry) and blackwater (wastewater from toilets).
These systems are typically restricted in that the bottom invert of the absorption field should be at least 2 feet above the seasonally high water table or impermeable layer (separation distance) and the permeation rate of the soil should be between 1 and 60 minutes per inch. Also, to ensure proper operation, the tank should be pumped every 3 to 5 years. Nitrogen removal of these systems is minimal and somewhat dependent on temperature. The most common type of failure of these systems is from clogging of the absorption field, insufficient separation distance to the water table, insufficient permeation capacity of the soil, and overloading of water.
Intermittent Sand Filters: Used in conjunction with pretreatment methods such as septic tanks and soil absorption fields. An intermittent sand filter receives and treats effluent from the septic tank before it is distributed to the leaching field. The sand filter consists of a bed (open or buried) of granular material 24 to 36 inches deep. The material is usually 0.35 to 1.0 mm in diameter. The bed of granular material is underlain with graded gravel and collector drains. These systems have been shown to be effective for nitrogen removal, however, this process is dependent on temperature. Water loading recommendations for intermittent sand filters are typically between 1 and 5 gallons per day/square foot (gpd/ft2) but may be higher, depending on wastewater characteristics. Primary failure of sand filters is due to clogging, and maintenance is recommended to keep the system performing properly—resting the bed, raking the surface layer, or removing the top surface medium and replacing it with clean medium. In general, the filters should be inspected every 3 to 4 months to ensure that they are operating properly.
Intermittent sand filters are used for small commercial and institutional developments as well as individual homes. The size of the facility is limited by land availability. The filters should be buried in the ground, but they may be constructed above ground in areas of shallow bedrock or high water tables. Covered filters are required in areas with extended periods of subfreezing weather. Excessive, long-term rainfall and runoff may be detrimental to filter performance, requiring measures to divert water away from the system (USEPA, 1980).
Recirculating Sand Filters: A modified intermittent sand filter in which effluent from the filter is recirculated through the septic tank and/or the sand filter before it is discharged to the soil absorption field. The addition of the recirculation loop in the system may enhance removal effectiveness and allow media size to be increased to as much as 1.5 mm in diameter.
Buried or recirculating sand filters can achieve a very high level of treatment of septic tank effluent before discharge to surface water or soil. Dosed recycling between sand filter and septic tank or similar devices can result in significant levels of nitrification/dentrification, equivalent to between 50 and 75 percent of overall nitrogen removal, depending on the recycling ratio. Regular buried or recirculating sand filters may require as much as 1 square foot of filter per gallon of septic tank effluent.
Mound Systems: An alternative to conventional OSDS and are used on sites where insufficient separation distance or permeation conditions exist. Mound systems are typically designed so the effluent from the septic tank is routed to a dosing tank and then pumped to a soil absorption field that is located in elevated sand fill above the natural soil surface. There is evidence suggesting that pressure dosing provides more uniform distribution of effluent throughout the absorption field and may result in better performance. A major limitation to the use of mounds is slope.
Where adequate area is available for subsurface effluent discharge, and permanent or seasonal high ground water is at least 2 feet below the surface, the elevated sand mound may be used in coastal areas. This system can treat septic tank effluent to a level that usually approaches primary drinking water standards for BOD5, suspended solids, and pathogens by the time the effluent plume passes the property line for single-family dwellings. A mound system will not normally produce significant reductions in levels of total nitrogen discharged, but should achieve high levels of nitrification.
Evapotranspiration (ET) and Evapotranspiration / Absorption (ETA) Systems: Combine the process of evaporation from the surface of a bed and transpiration from plants to dispose of wastewater. The wastewater would require some form of pretreatment such as a septic tank. An ET bed usually consists of a liner, drain field tile, and gravel and sand layers. ET and ETA systems are useful where soils are unsuitable for subsurface disposal, where the climate is favorable for evaporation, and where groundwater protection is essential. In both types of systems, distribution piping is laid in gravel, overlain by sand, and planted with suitable vegetation. Plants can transpire up to 10 times the amount of water evaporated during the daytime. For an ET system to be effective, evaporation should be equal to or greater than the total water input to the system because it requires an impermeable seal around the system. In the United States, this limits use of ET systems to the southwest. The size of the system depends on the quantity of effluent inflow, precipitation, local ET rate, and soil permeability (Otis, undated).
Aerobic Treatment Units – Can be employed on-site. These systems require regular supervision and maintenance to be effective. An aerobic bacteriological farm can digest 90% to 95% of the solid wastes that are deposited into the septic tank. Typically, oxygen is supplied to a septic system when there is a problem with pumping frequency or the overall effectiveness of the system. The typical design of these systems is such that a small compressor is located near the sewer line as it exits the house, which provides oxygen for the tank.
Disinfection Systems – Chlorination, ozonation, and ultraviolet disinfection are the most common methods of disinfection in the U.S.Chlorine, the most widely used disinfectant in municipal wastewater, destroys organisms by oxidizing cellular material. Chlorine can be applied as chlorine gas, hypochlorite solutions, and other chlorine compounds in solid or liquid form.
Ozone, an unstable gas generated by an electrical discharge through dry air or pure oxygen, is another oxidizing agent. Ultraviolet radiation, generated by an electrical discharge through mercury vapor, is absorbed into the genetic material of microorganisms and hinders their ability to reproduce.
Care of Septic Systems
To maximize the useful life of a septic system and prevent premature failure, all systems require proper care and periodic maintenance. King County, Washington’s Public Health Department recommends the following proper care procedures.
- Inspect your septic tank once every year and pump as necessary. Solids will eventually fill the tank and pass them into the drain field, mound or sand filter, which can lead to expensive repairs.
- Avoid flushing harmful material into the septic tank. Never put grease, any kind of paper (other than toilet paper), cigarettes, coffee grounds, sanitary napkins, solvents, oils, paint, caustic chemicals or pesticides into the tank.
- Avoid the use of any type of chemical or biological septic tank additive. Additives do not improve the performance in a septic tank. They are not a substitute for routine pumping, and some can be harmful to the system or the environment.
- Limit garbage disposal use. A garbage disposal can lead to a significant increase in solid build-up and waste strength problems in a septic system. Therefore, they are not recommended for use with a septic system. If your house already has one, limit the amount that it is used. Don’t construct patios, carports, decks or use landscaping plastic over the drain field or septic tank. The system should be kept accessible for proper maintenance and repair and the drain fields need oxygen in order to work properly. When soil is compacted, the drain field paved over or covered, oxygen cannot get into the soil. Keep all vehicles off the septic tank and drain field areas. Vehicular traffic is a major cause of damage to septic systems. Septic tanks are typically not designed for vehicular traffic and may crack or collapse as a result. Drain field pipes can be easily crushed by cars being driven over them. Vehicles also compact the surrounding soil, which prevents proper drainage. Direct water from roof drains and surface drainage away from the drain field and septic tank. Additional water from these sources may overload the drain field. Surface and ground water that enters the septic or pump tank can easily fail a system even though household water use is well within the design capacity of the system. Don’t dispose of water from hot tubs into the septic tank. Large volumes of water and residual chlorine can be extremely harmful to your septic system. Check with local jurisdictions for proper disposal of water from hot tubs. Keep a detailed record of all maintenance activities. Be aware of the location of all septic system components. A septic system as-built is the best source of this information. Know where the septic tank, pump tank, drain field and reserve areas are located. Protect these areas from impacts of any driveway, out building, patio, deck, swimming pool, sports court or landscaping projects.
- Don’t plant trees and shrubs over septic tanks or drain fields. The water-seeking roots of these plants can damage your home septic system. Grass or shallow-rooted plants tend to be the best cover for septic systems.
Use water wisely. Keep the amount of wastewater entering the septic system well below the “daily designed flow,” which is the maximum number of gallons the system is designed to handle per day. For a three-bedroom house, the daily designed flow in gallons per day (gpd) is 450; for a four-bedroom house, it’s 480 gpd. A septic system cannot be run at its peak capacity for very long without problems developing. Using more water than the system is designed to manage is one of the leading causes of premature septic system failure.
To reduce the risk of water overloads, use “low flow” fixtures on faucets, showerheads, and toilets (many newer homes come with low flow fixtures). Front loading washing machines use considerably less water than top load models. Do laundry throughout the week, rather than all on a single day. Promptly repair all leaky faucets and toilets.
Key Benefits Of Inspections
- To provide a current evaluation of the system.
- To prevent expensive post purchase problems due to the system not being evaluated.
- A working knowledge of the system and the maintenance required.