Septic tanks are sometimes not cost effective nor are they the only option when building. Knowing the alternatives to a septic tank can help you financially. It's also important to understand which alternative is most useful for your land.
A leach field operates similar to a leaching system connected to a septic tank without a tank. The effluent flows from the house to perforated pipes within a layer of gravel-filled trenches. The effluent seeps into the gravel from the perforated pipes and then the soil. Less space than traditional septic systems is needed. Leach field beds can be layered. There are size limitations to beds because excavation must be handled from the sides to prevent compaction of the bed bottom. Slopes steeper than 5 percent aren't adaptable to leach fields. Minimum soil depths of 18 inches are needed below the bed.
The lagoon system is used to treat effluent by exposure to air, sunlight and bacteria. Storage tanks collect effluent, then drain into solid piping ending at the bottom of the lagoon. Lateral fields are used to catch the overflow, which drains into the soil. Lagoons cost less than septic tanks and are easily installed. Lagoons are low maintenance. Fencing and gates are needed to secure the lagoon. Surface vegetation must be removed for efficiency. Lagoons are difficult to place in rocky soil or on steep slopes.
In a mound system, the effluent is pumped into a mound through distribution networks in the upper portion of the sand. The effluent goes through the soil, the fill material, then the natural soil. Use this system in areas with high groundwater, clay or bedrock soil. This is a low maintenance system. These systems require level land, are difficult to design and can be expensive. Regular inspection of the system is required, and these systems can be crippled by power failures.
This system has a primary treatment unit with two compartments and a rock-lined bed. The bed has 12 inches of rock and an overflow lateral field. Use of aquatic plants helps treat the effluent with excess effluent placed in the lateral field. The fields can be put on irregular or segmented lots and can be placed within areas with shallow water tables or high bedrock. Disadvantages include a higher level of maintenance compared with conventional systems. Wetlands are more costly to install and have an unknown lifespan.
Compost toilets naturally break down effluent. The effluent is placed in a bin below the toilet where decomposition takes place. Adding wood shavings, straw or leaves helps the process. The bin is emptied in an area of the yard and buried. This system eliminates septic tanks. Compost toilets are good for areas where other systems cannot be installed. Not all areas allow composting toilets as a standalone system. Improper operation of the system can create problems with disposal of solid waste and graywater. These systems need constant heating and venting to operate properly, which requires a constant electrical supply.