INI; Inflow Infiltration: Failing collection systems allow seasonal high groundwater to enter the system, overloading treatment plants that then release partially treated wastewater into receiving environments.
The collection system for OWTS is your household plumbing, if you've got a leak there, you'll know it!
Non-point source pollution: No one wants to talk about the reverse affects of INI, in the dry months when water tables are low, those same leaky collection systems seep raw waste into the groundwater.
A well designed and maintained OWTS releases only treated wastewater back into the environment and has no adverse effects on groundwater.
Watershed water balance: Extracting water from the ground in a local area and sending it via pipelines called collection systems many miles away, creates an imbalance in the water table impacting springs, streams and wells, as well as local vegetation.
OWTS treat and recycle precious water back into the environment, replenishing groundwater, springs and streams.
Point source pollution: Many big pipe sewers discharge into receiving waters. Nutrient loading is an issue even in the best operated systems. Did you know that 1,000,000 gallons per day of highly treated wastewater with a nitrogen level of 2 ppm, results in 17 lbs. of nitrogen per day or 6,250lbs per year being released into the receiving environment?!
Denitrification of wastewater is one of the focuses in modern designs of OWTS. Some of the new technologies have denitrification built right into them while others use vegetation and evapotranspiration to remove the nitrogen.
Thermal pollution: High volumes of treated wastewater discharged into receiving waters also affect temperature and surrounding aquatic life.
The natural process that support OWTS love the warm wastewater that comes from your home. Biological activity doubles with every 10 degree C increase in temperature. (that is of course until the thermal death point!)
Risk assessment: If a central wastewater treatment facility malfunctions the results can be catastrophic. Unwanted nutrients such as nitrogen, phosphorus along with nasty pathogens can be directly discharged into receiving waters.
If an OWTS malfunctions, not only does the very annoying alarm let you know, but the potential for disaster is much less. Some of the modern day OWTS will actually call or email your Qualified Service Provider directly, and you won't even be disturbed!
Beneficial reuse: OWTS releases treated wastewater back into the ground rather than into rivers, bays or oceans.
Financial consideration: The comparative cost of big pipe sewers including, hook up fees and annual usage fees is nearly the same as installing and operating a state of the art OWTS when amortized over a 30 year period.
As the OWTS Industry develops, new products and competition will continue to bring costs down. And once it's in, you don't have to worry about the next sewer rate hike or assessment.
Managed development: OWTS allows the practical development of properties based on site characteristics instead of depending on the expansion of big pipe sewers. OWTS also control overbuilding by making sure each lot is big enough to support it's own waste discharge.