April 16, 2006


Septic tanks, groundwater coexist in delicate balance

Improper disposal can threaten health

By Patrick Bean
For the Poughkeepsie Journal

Spencer Ainsley/Poughkeepsie Journal
Walt Ferguson, with M&O Sanitation in Poughkeepsie,
vacuums raw sewage out of a residenial septic tank.

Flushing toilets and pouring things down drains might seem like the end-point in the relationship with our waste.

But the waste doesn't simply disappear. It is scurried off to a sewage treatment plant or septic tank below ground.

In areas beyond the reach of central water and sewer lines, homeowners depend on the ground for treating waste from septic systems. The ground is also the source for potable water.

"It is important for homeowners with individual wells and septics to properly maintain them, because whether they realize it or not, they are recycling their water," said Scott Chase, executive director of the Dutchess County Water and Wastewater Authority.

Improper maintenance and use of septic systems can cause bacterial or chemical contamination of the groundwater, which in turn can damage the environment, make people sick and result in the need for expensive repairs.

Solids, oils separate

Most septic systems take wastewater from the home and send it to a settling tank. In the tank, solids settle to the bottom while oils and greases rise to the top. The intermediate level includes a liquid effluent that travels out of the tank into an absorption field, where the wastewater will trickle through the soil and ground.

The filtration of the water through the ground, combined with bacteria present in the soil, naturally treats the waste before it returns to the water table. What goes down the drain, including chemicals that aren't disposed of properly, might end up coming back into the home through a faucet.

Some easy steps can be taken to prevent problems and the resulting cost for cleanup or repairs.

"There are two basic rules. Only put biodegradable human waste down the toilet and don't use it for chemical disposal. The aquifer can treat or dilute many types of contaminants, but your stronger chemicals will not be adequately diluted or broken down," said Russell Urban-Mead, a hydrologist with the Chazen Companies in Poughkeepsie. "The other basic rule is to pump the solids out of the septic tanks," he said.

Urban-Mead is the author of a soon-to-be released report for Dutchess concerning the relationship between septics and sustainable groundwater resources. The amount of waste the ground can process depends on the type of soil present.

Problems from septic tanks can arise in several ways. If solids accumulate because of a failure to pump out the system, oils and solids can enter and clog the drain field. When solids get into the drain field, water is prevented from passing through the soil, essentially plugging the soil.

Avoid big problems

Avoid the disposal of items that do not easily decompose, such as cigarette butts, paper towels and garbage disposal waste to prevent the accumulation of solids in the settling tank. If there is a glut, the solids will move toward the drain field and cause a clog.

A clog can lead to drain field repairs or frequent pump-outs. Sewage could also back up into homes or emerge at ground level, causing a health hazard for people who come into contact with the waste.

Reducing water use and preventing storm water or surface water from entering the drain field will prevent unnecessary stresses on the soil and allow it to maintain its functionality.

Planting and keeping trees near the drainage field can also lead to broken pipes due to root intrusion.

Malfunctioning septic systems can contaminate nearby wetlands, creeks, streams, lakes or drinking water wells. Surface waters and wells can be contaminated with excess nutrients, fecal coliform bacteria and E. coli associated with human waste.

Fecal coliforms and E. coli bacteria can also decrease the amount of dissolved oxygen within ponds, lakes and streams, and essentially choke off the aquatic environment for organisms such as fish.

Common contamination

The Dutchess County Health Department does not track the number of contaminated drinking wells as a result of failing septics but "it happens all over," said Chief of Engineering John Glass.

Chemicals such as solvents, paints, disinfectants, pesticides and poisons can also leach into drinking wells, soils and nearby streams and lakes. The chemicals can disrupt the proper function of septic systems by destroying the natural bacteria in the soils, and threaten the health of human neighbors and surrounding environment.

The responsibility for maintaining wells and septics falls upon the private landowners. It's the individual's responsibility to avoid improper disposal of materials and test for well contamination.

Glass said drinking wells contaminated with bacteria can be disinfected but if the problem persists, ultraviolet disinfection systems would have to be installed in the home. If the problem arises from chemical contamination, a pricier carbon filter would be needed.

"Homeowners need to understand where their water is coming from and where the waste from their homes is going," Urban-

Mead said. "Knowing that, you use greater discretion in what you send to your septic system and you are more careful to monitor water quality."

Tips for maintaining your septic tank

  • Pump out septic tanks at least every two to three years.
  • Check for pooling water or grass discoloration above the drain field. These are signs of a malfunctioning system.
  • Avoid excessive quantities of detergents, kitchen and laundry wastes and household chemicals.
  • Avoid using biological and chemical additives. These products may pollute groundwater or damage the structure and functionality of the system.
  • Avoid disposal of cigarette butts, disposable diapers, sanitary napkins, plastics and other products that won't decompose easily.
  • Limit or stop the use of garbage disposals. The substantial increase in solids entering the septic tank can lead to more frequent maintenance.
  • Prevent surface water from impervious surfaces such as roofs, patios and driveways from draining into sewage treatment system or field.
  • Avoid planting or having trees near the absorption lines, since the roots may clog or damage the system.
  • Do not enter your septic tank.
  • Conserve water usage by checking leaky toilet valves and sink fixtures, installing water-saving fixtures and avoiding wasteful practices.

Copyright 2006, Poughkeepsie Journal. Reprinted with Permission.
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