Solving wastewater disposal problems with the help of Geoflow subsurface drip systems

Sewage disposal systems in older cities throughout the country are using outdated designs and infrastructure, many dating to before World War II, excessive sewage overflow is a problem. Heavy rainfall during some times of the year combines with inadequate sewer collection capacity to cause overflows. These overflows bypass treatment plants and enter our waterways, polluting the environment exposing us to contaminants. For instance, a sewer system in Hamilton County, Ohio releases about 75 million gallons of untreated sewage a year into a creek which winds through western Cincinnati. People there are exposed to disease causing microorganisms and toxic contaminants. These combined sewer systems were effective in the past but due to growing populations and more industrial toxic waste they have become totally inadequate. However, solutions are being developed.

“Reclaimed water” has been developed as a partial solution. When the sewage is treated in newer systems in a three-step process and then disinfected, it is believed to be safe to discharge into rivers, lakes, streams and wetlands. This reclaimed water is also being used to irrigate golf courses, farms, city parks, school playgrounds and sporting fields. Other uses include fire protection, street cleaning, apartment landscaping construction projects and more. But more recently it’s been discovered that reclaimed water is itself subject to contamination as it is being stored in golf course lakes, ponds, lagoons and uncovered tanks prior to use, so using it may also be a health hazard.

New technology has been detecting minute amounts of chemicals from prescription drugs which even the most sophisticated treatment plants are unable to neutralize. Other pollutants, including viruses are now also being discovered in reclaimed water and people can be exposed to them in various ways, especially when the water is sprayed, like on the golf course, in the park, the nursery or even on the school grounds.

As problems with reclaimed water are discovered, the over-all challenge of discharging treated wastewater is continuing to grow and is leading to important modifications and more research. Research shows that even current disinfection methods using combined chlorine are not good enough for total viral disinfection.

One of the better solutions to the problem is soil dispersal using subsurface drip technology. This method involves placing tubing to form drip lines under at least 8 inches of soil.  The treated wastewater is dispersed underground to root zones. This is done slow enough for the ground to absorb the pathogens that are still present in the water. The depth allows most pollutants, including nitrates not consumed by the soil, to fertilize the nearby vegetation.

Transition to a subsurface drip dispersal system for a community near Yosemite National Park was undertaken in the late 1990’s.  Vacuum breakers were used to prevent dirt from being sucked into the drip line. Pressure was maintained in the drip lines by the use of pressure compensating emitters. The ends of the drip lines were connected to form a common flushing line. A recent inspection of the site revealed no surfacing and no overland flows of the wastewater.

In Yosemite National Park itself the Tenaya Lodge is a full service resort. Due to the resort’s occupancy growth, the park’s capacity to dispose of effluent needed to expand. This expansion used GEOFLOW subsurface drip lines, increasing the disposal capacity at the site to more than 100,000 gallons of treated wastewater per day. Water from nearby wells is regularly tested and remains unaffected by the drip line system. After the system was installed the area was replanted with ferns and grasses. Recent inspections have revealed no surfacing or overland flows of the treated water. Also the vegetation abounds and has covered the area…being fertilized by the drip flow system. The vegetative growth helps prevent erosion and creates a stable area. It also expands water holding capacity, limiting runoff during heavy rain. Additionally, the increased organic plant mater in the soil from biological activity provides more food and moisture for plants and helps to destroy pathogens in the wastewater.

While combined sewers and poorly tested reclaimed water use continue to cause problems that are huge, GEOFLOW subsurface drip disposal is offering some solutions. In fact reclaimed water can safely continue to be used but in combination with subsurface drip systems for landscapes, ball parks, golf courses and playgrounds. This is being done now in many places with excellent results.

Well designed wastewater treatment systems are now being used in conjunction with GEOFLOW subsurface drip disposal installations to provide alternatives and help meet the challenges faced by many wastewater treatment facilities. Wastewater disposal: it’s a problem, but one that subsurface drip systems are helping to solve.