After the Flush

A decentralized wastewater treatment system – a package plant – serving an apartment building in Suffolk County, New York.

A decentralized wastewater treatment system – a package plant – serving an apartment building in Suffolk County, New York.

By Kristina Heinemann

What happens after you flush a toilet in New York City?  In most cases household sanitary waste, as well as domestic wastewater from your kitchen and laundry, travels to a central wastewater treatment plant.  But that is not always the case!  In some areas, for example in many parts of Suffolk County, New York and in less developed areas of both New York and New Jersey, domestic wastewater is treated right where it is generated. In these instances wastewater from sinks, tubs, washing machines and toilets typically flows into in a septic tank and then is distributed or dispersed to a larger area where wastewater flows under the ground and is further treated by natural chemical and biological processes within the soil. This type of wastewater treatment is referred to as decentralized wastewater treatment to distinguish from instances where wastewater flows through large sewer pipes to a centralized wastewater treatment plant.  Despite being more common in rural areas, decentralized onsite treatment can even be found in the outer boroughs of New York City and in one instance has been incorporated into the award winning design of a high rise apartment building, the Solaire* in lower Manhattan.

*The Solaire was awarded LEED® Gold Certification by the United States Green Building Council.

Precast concrete rings of the type used in residential leaching pools in Suffolk County, NY

Precast concrete rings of the type used in residential leaching pools in Suffolk County, NY

Just what is decentralized wastewater treatment?

Decentralized wastewater treatment consists of a variety of approaches for collection, treatment, and dispersal/reuse of wastewater. The systems are part of the nation’s permanent infrastructure and can be managed as stand-alone facilities or integrated with centralized sewage treatment systems. They provide a range of treatment options from simple, passive treatment with soil dispersal, commonly referred to as septic or onsite systems, to more complex and mechanized approaches, such as advanced treatment units that collect and treat waste from multiple buildings and discharge to either surface waters or the soil.

Why use decentralized wastewater treatment?

Decentralized wastewater treatment can be a smart alternative for communities considering new systems or modifying, replacing, or expanding existing wastewater treatment systems. For many communities, decentralized treatment can be:

  • Cost-effective and economical
    • Avoiding large capital costs
    • Reducing operation and maintenance costs
    • Promoting business and job opportunities
  • Green and sustainable
    • Benefiting water quality and availability
    • Using energy and land wisely
    • Responding to growth while preserving green space
  • Safe in protecting the environment, public health, and water quality
    • Protecting the community’s health
    • Reducing conventional pollutants, nutrients, and emerging contaminants
    • Mitigating contamination and health risks associated with wastewater

The bottom line is …

Decentralized wastewater treatment can be a sensible solution for communities of any size and demographic. Like any other system, decentralized systems must be properly designed, maintained, and operated to provide optimum benefits. Where they are determined to be a good fit, decentralized systems help communities reach the triple bottom line of sustainability: good for the environment, good for the economy, and good for the people.

Stay tuned for more information on how to care for a decentralized treatment system and   EPA’s Septic Smart tips. See for a preview!

About the Author: Kristina works in the Clean Water Division and coordinates the Region’s decentralized wastewater treatment (also known as septic systems, onsite wastewater treatment systems) activities in New Jersey, New York and the Caribbean. She lives in Suffolk County, New York and there has had the opportunity to experience first-hand living with and maintaining an onsite wastewater treatment system. Although retirement is still a number of years away, Kristina does sometimes dream of using her golden years to create a decentralized community wastewater treatment system and septic management district in her neighborhood to further protect groundwater and surface water quality.

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