What is a Septic System

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How a Septic System Works

The most common septic system in Arizona is a conventional system. Conventional septic systems typically consist of two major components: the septic tank and the absorption field (also known as the drain field/leach field).

Wastewater flows from the home to the septic tank via the sewer line. A septic tank is a watertight structure constructed of either concrete, fiberglass, or plastic and is designed to take in and hold wastewater. This wastewater is held in the septic tank long enough to separate into three distinct layers. The top layer is the scum layer, which is composed of grease, oils, and floatables. The bottom layer is the sludge layer, which consists of solids and waste that cannot float. Anaerobic bacteria present in the sewage help break down some of the waste in the septic tank. The middle layer is the liquid effluent layer, or "water layer," which is allowed to flow out of the septic tank through T-shaped baffles. This effluent layer flows out into the absorption field/leach field.

The leach field usually consists of a series of trenches that allow the liquid effluent to be emitted slowly. Each trench consists of a porous pipe on top of a media, such as sand and/or gravel. The liquid effluent is allowed to slowly percolate into the media and surrounding soil, where the remaining pathogens, viruses, and bacteria are naturally treated.

Benefits of using a conventional system include:

• Low maintenance
• Low cost of operation
• No electricity needed

Disadvantages of conventional systems include:

• Cannot be installed in sensitive areas, and as many soil types as aerobic systems can
• Produces a lower-quality effluent than aerobic systems

Chambers

Infiltrator chambers can be used in almost any conventionsl septic disposal field application. Wherever stone and pipe are installed, infiltrator chambers can be used. This includes trench, bed, and elevated mound installations. Infiltrator chambers provide superior treatment capabilities in pressure dosing, level distribution, serial distribution, evapotranspiration, and sand filter applications. Chambers also come in a traffice graded form for use in driveways when space is minimal. 

These chambers are an alternative to the traditional gravel leach fields. They offer the following benefits: No clogging of the soil from the dusty materials found in gravel trench systems, can support up to 16,000 pounds of accidental loads (never drive on your leach field if you can avoid it), fit in a smaller space than traditional gravel leach fields making it possible to minimize the excavation in your yard. The sides of the chambers are louvered to help prevent dirt and roots from entering the fields. The interior is also large enough to protect against roots clogging up the line. They are made from more than 90 percent recycled materials.

Many installation requirements and options are governed by local codes instituted by the health department in your area. When in question, check with the local health department for specifics and follow their code instructions.

EZ Flow

EZ flow can be used in almost any septic leach field application. Wherever stone and pipe can be installed, EZ flow can be used. This includes trench, bed, and elevated mound installations. EZ flow provides superior treatment capabilities in pressure dosing, level distribution, serial distribution, evapotranspiration, and sand filter applications. The Infiltrator EZ Flow septic system is an environmentally friendly replacement to traditional stone and pipe leach fields using an engineered geosynthetic aggregate modular design. Preassembled units of EZ flow include a 3" or 4" perforated pipe surrounded by aggregate and held in place with durable, high-strength netting. Additionally, EZ flow is available in a variety of configurations and can be designed for shallow or deep installations. This type of system can be a great tool. It offers a great deal of flexibility in design and installation. System sizing is determined by each local health department. The system sizing is normally calculated based on a combination of factors, including soil type and volume of wastewater (normally estimated using a number of bedrooms). Typically, health departments have approved sizing reductions of 25 to 50 percent when EZ flow is specified.

Many installation requirements and options are governed by local codes instituted by the health department in your area. When in question, check with the local health department for specifics and follow their code instructions.

Gravel Trench

A decentralized wastewater treatment system consists of a trench or bed subsurface wastewater infiltration system, known as a leach field. The gravel/stone leach field is a design that has existed for decades. The effluent is piped from the septic tank to a shallow underground trench of stone or gravel. A geofabric or similar material is then placed on top of the trench so sand, dirt, and other contaminants do not enter the clean stone. Effluent from the tank filters through the stone and is then further treated by microbes once it reaches the soil below the gravel/stone trench. Gravel/stone systems are relatively large in overall footprint and may not be suitable for all residential sites or conditions. This type of leach field uses a variety of piping to disperse the effluent over the fields, including tiles, flexible corrugated pipes, perforated pipes, bricks, and more. Check with your local county to find approved products in your area.

Fast Septic System

An above-grade blower motor constantly pushes air into the airlift, which produces robust recirculation of oxygenated water throughout the submerged media. The oxygenated water supports the growth of useful microorganisms on the surface of the media. These attached growth microorganisms break down the organic material in the wastewater. Microbial growth on the media surface is sloughed off by the vigorous aeration provided by the airlift. The excess solids settle out of the media to the bottom of the tank, where they are stored for intermittent removal. Treated effluent leaves the Micro FAST module through a built-in baffle into the receiving environment. These systems are used in situations where there is a limiting layer of rock or clay. Fast systems are usually 2 to 3-tank systems that require a pump to move the effluent to the pressurized leach field, which resembles drip irrigation piping. Micro-fast systems use absorption and evaporation to dispose of the effluent.

Eljin Septic System

The Eljen GSF system technology has over 50 years of success in the onsite industry, with over a hundred thousand systems currently in use. The GSF is recognized by regulatory officials and experts in the industry as one of the most reliable wastewater treatment technologies in the marketplace today. The GSF technology is based on scientific principles, which state that improved effluent quality increases soil absorption rates. GSF’s proprietary two-stage Bio-Matt™ pre-filtration process improves effluent quality while increasing reliability and ease of operation. Incoming effluent and bacteria flow through the perforated pipes, which distribute the effluent over the modules. Open-air channels in the modules allow beneficial bacteria to grow on the Bio-Matt fabric and treat effluent. A geotextile fabric covers the top and sides of the GSF Modules, protecting the system’s sand and soil from fine particles that can clog the system. It also helps maintain effluent storage inside the modules. After effluent passes through the GSF Modules, a lighter, secondary biomat forms on the layer of sand below the system, where the treatment process is continued. The treated effluent is then absorbed by the native soil, where final filtration takes place. Eljen systems are used when the soil is found to have a limiting layer and further treatment of the effluent is needed. Eljen systems can be used in either gravity or pump situations. The shallower these systems are, the better absorption and evaporation are used to dispose of the effluent.

There is a huge variety of septic systems approved for use in the state of Arizona. Listed above are just a few which can actually be mixed together when necessary. If further information is necessary contacting a licensed engineer would benifical.

Onsite Septic Servvice uses Ocotillo Engineering for all septic design services.

Ocotillo Engineering 

ocotilloengineering.com

ocotilloeng@gmail.com

Phone: (520)437-7226