Community septic systems are increasingly recognized as a sustainable solution for wastewater management, particularly in rural and densely populated areas. These decentralized systems collect and treat wastewater from multiple dwellings, providing an efficient alternative to traditional municipal sewer lines. By utilizing innovative technologies and natural processes, community septic systems effectively reduce environmental impact while promoting groundwater replenishment. This approach not only offers significant cost savings for homeowners but also fosters independence from municipal services. Understanding the benefits and types of community septic systems is essential for making informed decisions about wastewater management in various settings.

What are Community septic systems?

Septic systems are underground wastewater treatment structures that use a combination of natural and technological processes to treat wastewater from household plumbing produced by bathrooms, showers, kitchen drains and laundry.

Types of Septic Systems

The design and size of a septic system can vary widely, from within your neighborhood to across the country, due to a combination of factors. These factors include household size, soil type, site slope, lot size, proximity to sensitive water bodies, weather conditions, or even local regulations. Below are ten of the most common types of septic systems used, followed by illustrations and descriptions of each system. The list is not all-inclusive; there are many other types of septic systems.

Conventional Systems:

Septic Tank

A septic tank is a buried, watertight tank designated and constructed to receive and partially treat raw domestic sanitary wastewater. Heavy solids settle to the bottom of the tank while greases and lighter solids float to the top. The solids stay in the tank while the wastewater is discharged to the drainfield for further treatment and dispersal.

Conventional System

A conventional decentralized wastewater treatment system consists of a septic tank and a trench or bed subsurface wastewater infiltration system, known as a drainfield. A conventional septic system is typically installed at a single-family home or small business.

The gravel/stone drainfield 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 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.

Chamber System

Gravelless drainfields have been widely used for over 30 years in many states and have become a conventional technology replacing gravel systems. They take many forms, including open-bottom chambers, fabric-wrapped pipe, and synthetic materials such as expanded polystyrene media. The gravelless systems can be manufactured with recycled materials and offer a significant savings in carbon footprint.

An example of a gravelless system is the chamber system. The chamber system serves as an alternative design to the gravel/stone system. The primary advantage of the chamber system is increased ease of delivery and construction. They are also well suited to areas with high groundwater tables, where the volume of influent to the septic system is variable (e.g., at a vacation home or seasonal inn), in an area where gravel is scarce, or in areas where other technologies such as plastic chambers are readily available.

Alternative Systems:

Drip Distribution System

The drip distribution system is a type of effluent dispersal that can be used in many types of drainfields. The main advantage of the drip distribution system is that no large mound of soil is needed as the drip laterals are inserted into the top 6 to 12 inches of soil. The disadvantage of the drip distribution system is that it requires a large dose tank after the septic tank to accommodate the timed dose delivery of wastewater to the drip absorption area. Additional components, such as electrical power, are necessary for this system, requiring an added expense and increased maintenance.

Aerobic Treatment Unit

Aerobic Treatment Units (ATUs) use many of the same processes as a municipal sewage plant, but on a smaller scale. An aerobic system injects oxygen into the treatment tank. The additional oxygen increases natural bacterial activity within the system that then provides additional treatment for nutrients in the effluent. Some aerobic systems may also have a pretreatment tank and a final treatment tank including disinfection to further reduce pathogen levels.

The benefits of this system are that it can be used in homes with smaller lots, inadequate soil conditions, in areas where the water table is too high, or for homes close to a surface water body sensitive to contamination by nutrients contained in wastewater effluent. Regular life-time maintenance should be expected for ATUs.

Mound Systems

Mound systems are an option in areas of shallow soil depth, high groundwater, or shallow bedrock. The constructed sand mound contains a drainfield trench. Effluent from the septic tank flows to a pump chamber where it is pumped to the mound in prescribed doses. Treatment of the effluent occurs as it discharges to the trench and filters through the sand, and then disperses into the native soil.

While mound systems can be a good solution for certain soil conditions, they require a substantial amount of space and periodic maintenance.

Recirculating Sand Filter System

Sand filter systems can be constructed above or below ground. Effluent flows from the septic tank to a pump chamber. It is then pumped to the sand filter. The sand filter is often PVC-lined or a concrete box filled with a sand material. Effluent is pumped under low pressure through the pipes at the top of the filter. The effluent leaves the pipes and is treated as it filters through the sand. The treated wastewater is then discharged to the drainfield.

Sand filters provide a high level of treatment for nutrients and are good for sites with high water tables or that are close to water bodies, but they are more expensive than a conventional septic system.

Evapotranspiration System

Evapotranspiration systems have unique drainfields. The base of the evapotranspiration system drainfield is lined with a watertight material. After the effluent enters the drainfield, it evaporates into the air. Unlike other septic system designs, the effluent never filters to the soil and never reaches groundwater.

Evapotranspiration systems are only useful in specific environmental conditions. The climate must be arid and have adequate heat and sunlight. These systems work well in shallow soil; however, they are at risk of failure if it rains or snows too much.

Constructed Wetland System

A constructed wetland mimics the treatment processes that occur in natural wetlands. Wastewater flows from the septic tank and enters the wetland cell. The wastewater then passes through the media and is treated by microbes, plants, and other media that remove pathogens and nutrients. The wetland cell typically consists of an impermeable liner, and gravel and sand fill, along with the appropriate wetland plants, which must be able to survive in a perpetually saturated environment.

Cluster / Community System

A cluster (or community) decentralized wastewater treatment system is under some form of common ownership and collects wastewater from two or more dwellings or buildings. It conveys the wastewater to a treatment and dispersal system located on a suitable site near the dwellings or buildings. It is common to find cluster systems in places like rural subdivisions.

Community-Scale Options

Within a region, county, city, town, or neighborhood, the systems used to treat wastewater can vary significantly and may include both centralized and decentralized treatment options. The most appropriate system is selected based on factors such as cost, land availability, population density, and environmental conditions. In this illustrated example of a town, several types of decentralized systems are shown: a conventional septic system with a drainfield serving a single home, an onsite cluster system serving a commercial shopping center, and an offsite cluster system serving multiple houses and an apartment building.

Advantages of Septic Systems

Cost Savings

One of the primary advantages of using septic systems is the significant cost savings compared to municipal alternatives. The installation and maintenance of a septic system are generally cheaper, providing substantial cost benefits over time. Homeowners save money on installation and throughout property ownership due to reduced reliance on municipal services. Additionally, having a septic system means no monthly water or sewer bills, which can lead to considerable long-term savings. Regular maintenance costs are also minimal, with homeowners spending as little as five dollars monthly on yeast-based treatments to keep the system functioning efficiently.

Environmental Benefits

Septic systems offer notable environmental benefits by efficiently treating wastewater on-site and reducing water contamination risks. Treated effluent is returned to the soil, helping to replenish groundwater. Unlike municipal sewer systems, where sewage line leaks can cause widespread issues, any septic system leaks are contained to specific properties, minimizing environmental impact. Moreover, RCI Septic Service emphasizes the use of environmentally friendly materials and methods in all their installations. Eco-friendly practices in septic systems help alleviate environmental concerns and contribute positively to groundwater conservation.

Independence from Municipal Sewer Systems

Septic systems provide homeowners in rural areas a self-sufficient waste management option without relying on municipal services. This independence is particularly advantageous in rural settings where connecting to municipal sewer lines can be costly and impractical, especially when considering a septic tank system. Additionally, homeowners with septic systems are not subjected to municipal sewer rate increases.

Disadvantages of Septic Systems

Maintenance Requirements

Routine maintenance is crucial for the effective operation of a septic system and can prevent costly repairs. Annual maintenance fees for septic systems are generally much lower compared to recurring sewer charges. The most significant maintenance cost is usually the periodic pumping of the septic tank. For instance, pumping a tank ranging from 1000 to 1500 gallons averages between $300 to $350.

Neglecting maintenance can lead to serious issues such as slow drains, clogged pipes, and expensive repairs. Conventional septic systems, in particular, can become clogged if not properly maintained. However, homeowner maintenance for septic systems is generally lower compared to sewer systems.

Potential for System Failures

Septic systems can fail if not properly maintained or if inappropriate items are flushed down the drains. Common causes of system failures include blockages caused by items like wipes and feminine products or the use of harsh chemicals that disrupt the natural bacteria essential for the system’s function. Slow drains often indicate blockages in the septic system and require immediate attention.

Water accumulation around the drain field is another sign of system failure. This can result from soil compaction, clogged drain field pipes, or inadequate maintenance. Standing water near the septic tank or drain field usually signals saturation or a malfunction in the system that may require professional evaluation.

Limited Capacity

Septic systems are designed to treat a specific daily volume of wastewater, beyond which they can become ineffective. This limited capacity means that excessive water usage or an increase in household size can overwhelm the system, leading to potential failures.

Conclusion

Community septic systems offer a range of benefits, including cost savings, environmental advantages, and independence from municipal sewer systems. However, they also come with maintenance requirements, potential for system failures, and capacity limitations. By understanding the different types of septic systems and the importance of proper maintenance, homeowners can make informed decisions about their wastewater management solutions.

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