. Coast watch. Marine resources; Oceanography; Coastal zone management; Coastal ecology. Research: beachhead for an underground revolution There are over two million septic tanks in North Carolina, with some 50,000 new ones each year. Nowhere do they fail with more consequence than along the coast, where half a million residents use them, and where an estimated 70 to 90 percent of the soils are now thought to be unsuitable for conventional, on-site sewage disposal. Because the stakes were so high, and the alternatives to septic tanks so limited and expensive, Sea Grant began funding research i
. Coast watch. Marine resources; Oceanography; Coastal zone management; Coastal ecology. Research: beachhead for an underground revolution There are over two million septic tanks in North Carolina, with some 50,000 new ones each year. Nowhere do they fail with more consequence than along the coast, where half a million residents use them, and where an estimated 70 to 90 percent of the soils are now thought to be unsuitable for conventional, on-site sewage disposal. Because the stakes were so high, and the alternatives to septic tanks so limited and expensive, Sea Grant began funding research into coastal septic systems in 1977. The research, led by Bobby Carlile of North Carolina State University (NCSU), in- spired an underground revolution in on-site sewage disposal. What Carlile discovered was that many of the septic tank's limitations could be overcome if the flow of effluent from the tanks into distribution lines was controlled in even "; This he managed with low-pressure pumps, which periodically filled each distribution line, along its entire length, and used the greatest possible area of soil for treatment. For marginal soils, es- pecially dense clays with moderately high water tables, the distribution lines could be laid 12 inches deep. The cost remained low, about $800 for gravel, pipes and pumps (labor was ad- ditional). For very severe cases, on sites with impermeable clays or very high water tables, Carlile built his low-pressure systems into mounds of soils layered to percolate the wastewater safely. Since the mound was essentially a distribu- tion field construction above ground, soils had to be moved to the site, and costs ran into several thousands of dollars. On test sites along the coast and in- land, Carlile built these systems and tested them. Around them he dug sam- pling wells, where he measured water quality in the surrounding soils. The systems worked; wastewater was con- tained and treated. On test sites near estuaries, sampl
Size: 3163px × 790px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionunclibra, booksubjectoceanography
