Modern Sewers
For Rural Communities
Careful Planning And Funding Support Help Make
Vacuum Sewers A Reality In Tiny Orangefield, Texas
Folks who live in rural communities have many of the same aspirations that city people have. They want controlled economic growth, increased property values, and clean water and a healthy environment for their families. Cities assume a certain level of economic growth and often take water utilities for granted. It’s different for those of us who live in small communities; economic growth and prosperity don’t happen organically – they require careful planning and investment.
Orangefield, Texas, recently completed the first two phases of a wastewater collection and treatment project that is already paying dividends for our residents. Soon everyone in the area, at least those who choose to participate, will have access to a modern, efficient sewer system. It has taken about 15 years and lots of hard work, but our community now has a great water and sewer infrastructure that will enhance property values and make life more pleasant for everyone in Orangefield.
 A GROWING PROBLEM
Orangefield, located about 20 miles from the Texas gulf coast, developed as a community almost 100 years ago. The town grew rapidly during the oil boom of the 1920s, eventually reaching a population of 1,000 in 1930. The population dwindled significantly over the next couple of decades, but eventually climbed to more than 2,000 by the most recent census.
Having never incorporated as a city, we have no municipal government and until recently, no public utilities. Homeowners were responsible for their own water and sewer, with most opting for wells and septic tanks. Because the soil in Orangefield is ill suited to absorb sewage, many homes had untreated wastewater in ditches, some along the front of their property. This was certainly unattractive, but it also created an environmental hazard as sewage often made its way to nearby Cow Bayou, which is part of the Sabine River Authority Watershed area.
The sewer problem grew as the local population increased, and by the 1990s Cow Bayou had become polluted to the point the aquatic life was almost gone and no one wanted to fish or swim there. Furthermore, the raw sewage meandering through local ditches was unsightly, smelly and unappealing to potential homebuyers and developers.
Clearly, Orangefield needed a sewage collection and treatment system, but where does a rural community get the money when there is no taxing authority? The effort to provide our town with water and sewage service actually began in the early 1990s with the development of the Orangefield Water Supply Corporation. By 2005 there were more than 1700 water customers. Attention soon shifted to the community’s need for sewers.
PLANNING THE SOLUTION
The Water Supply Corporation got the ball rolling in 2000 with an information campaign and sign-up program. The board asked all interested persons to put down a deposit toward the development of a sewage system. The result was a $100,000 war chest that enabled the board to begin researching solutions to the problem.
An engineering firm, J.F. Fontaine and Associates of Palestine, Texas was retained to begin a detailed study of the situation. They not only provided engineering consultation, they also helped us find the funding needed for the project. The USDA’s Rural Development department provided an initial funding package, but it proved to be inadequate for the project. Rural Development then re-examined the situation based on local income levels and was able to provide additional monies, including some federal grants. With enough funding finally in place, we were able to begin work on the first two phases of the installation in July 2009.
The engineers for the project presented our board with different system designs for collecting sewage. It quickly became obvious that a gravity sewer system would not be a viable collection method. Because of the flat terrain of the area and a very high water table, installing collection lines would be expensive, disruptive and time consuming. The flat topography would require multiple lift stations and very deep collection lines. The fact that Orangefield has a high water table meant that the trenches would need shoring and dewatering. The project would take months, perhaps years, and cost millions of dollars
As a possible alternative, the engineers brought in AIRVAC representatives for a presentation of modern vacuum sewers. Vacuum systems operate on simple principals of physics and have proven over many years to be extremely reliable. Orangefield, with geography typical of many coastal areas, was a good candidate for vacuum technology.
 VACUUM SEWERS 101
From the home to the street, a vacuum system relies on gravity, just as conventional systems do, to transport wastewater. Near the street the sewage collects in a valve pit, which consists of a sump and pneumatic valve mechanism. When the wastewater in the sump reaches a predetermined level, usually about 10 gallons, the pneumatic valve releases the contents into the vacuum collection line. One or two homes are typically connected to a single valve pit
Vacuum pressure within the collection line propels the wastewater at speeds up to 18 feet per second toward the vacuum station. The speed of the wastewater helps scour the line and break up solids. The PVC collection line is laid in a sawtooth profile to ensure adequate vacuum levels at every point along the line.
Because the AIRVAC system relies on vacuum pressure rather than gravity to convey wastewater, the lines can be buried at shallower depths, usually 4-6 feet below the surface. Gravity lines in such flat terrain would require trenches reaching 10-15 feet deep to achieve the necessary slope. Shallower trenches mean faster, easier installation with less disruption to the neighborhoods and traffic.
A single vacuum station, which covers about the same footprint as a small house, can serve homes up to two miles away. Several pumping stations would be required for a gravity sewer system in similar circumstances. Also, vacuum systems are contained, meaning there is no odor and workmen rarely come in contact with raw sewage.
POSITIVE RESULTS
Although skeptical at first, our Water Supply Board soon began to see the numerous benefits of vacuum sewer technology. They approved the plan and with the help of AIRVAC engineers, phases one and three of a modern vacuum system were installed and put into operation. Now, only months after completion, the water in Cow Bayou is proving to be cleaner and the fish population will soon grow rapidly. Also, many of the ditches filled with sewage are dry and clean.
The cost to homeowners in Orangefield is about $60 flat rate per month for water and sewer service, though high water users will pay a bit more. At present, about 1,000 homes are signed up for both water and sewer service, and more are certain to join as the community grows. Also, other rural communities are now talking to us to find answers to their own water and sewer issues. It seems this small town has become a model for others to follow
The best news about Orangefield’s new vacuum sewer system is that it opens doors for growth and development for our community. Property values are up, which will help local school funding. The already outstanding schools in Orangefield will get even better and will help attract more families. It’s a winning formula for small rural communities that want to grow and prosper, and it all began with a plan for local public utilities.
This article appeared in the April, 2012 issue
of Water and Wastes Digest. If
you would like to read the entire story as it appeared in the magazine,
you can download
a pdf, or you may request
hard copies.
Return
to Municipal Projects page.
|
