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Water quality issues

Areas of concern – Eggstain and surroundings

We contract testing of our potable (drinking) water to a private company that is better equipped than our department to carry out the battery of tests needed to certify a water supply as superior, which has been our designation for two decades. The city's wells produce an ample supply of untreated water with levels of inorganic contaminants (salts, metals), pesticides and herbicides, organic chemical contaminants, and radioactive contaminants well below the maximum safe limits according to EPA guidelines. Following chlorination, our drinking water is free of coliform activity, Cryptosporidium parvum, Giardia, parasitic amoebae such as the Vahlkampfids, and other freshwater parasitic organisms. A fatality from exposure to Naegleria fowleri occurred in 1996, however the source turned out to be a contaminated river in central Texas, which the victim had visited a few days prior to hospitalization.

Sewage treatment practices

Most large cities have systems of sanitary sewers that carry wastewater from homes and businesses to a centralized facility for treatment. Eggstain is serviced by private septic systems. The original systems, installed in the 1920s, have been replaced within the last 30 years. Most of the systems installed during a minor construction boom in the 1950s remain in service. The City may eventually have to develop a centralized water treatment plant to accommodate recent population growth, as there is no space within or near the City that will accommodate further expansion of the septic systems.

Septic systems

A septic system is simply a small scale sewage treatment system used in areas that do not have access to centralized sewage treatment plants. Septic systems are best for rural areas, although in the United States many suburbs and small towns rely on them. The central component of a septic system is the septic tank. The work "septic" refers to the bacterial culture in the tank that processes the wastes piped into it. Most such systems use anaerobic bacteria to decompose or mineralize the material.

A typical septic tank consists of two chambers in series, with an outlet from the second "downstream" chamber leading to a section of ground called a leach field or drain field. As raw sewage flows into the first tank the solids settle to the bottom while the less dense components float. As anaerobic bacteria digest the settled solids they significantly reduce their volume. The liquid continues to flow into the second chamber where further settling and digesting occurs. The excess liquid is relatively clear and no longer contaminated with potentially harmful bacteria. It drains into the leach field, and any impurities that remain decompose in the soil. As the liquid percolates into the soil, it is either absorbed by the root systems of plants or is safely added to the groundwater. The sizes of the tanks and leach fields determine the volume a septic system can handle, but generally such systems are designed for low volume, residential use.

Most of the solid waste can be converted to water and carbon dioxide or other end products that can be safely reintroduced to the environment. Some solid materials are what we call "irreducible," that is, they cannot be further broken down by beneficial bacteria in the system. Irreducible solids must be pumped out periodically to prevent their filling the tank. A poorly maintained tank will eventually clog and sewage will back up into the residence, necessitating immediate attention. However a tank can fill partially with solids rendering the septic system ineffective and/or clogging the pipes in the leach field. Such conditions typically allow nearly raw sewage to percolate into the soil and possibly into the groundwater below. Eggstain has no ordinances mandating periodic maintenance of septic systems.

With periodic maintenance a well built septic system should be odor free and last for many decades. There is a number of ways in which the lifetime and efficiency of a system can be reduced, including the following.

  • Excessive dumping of cooking oils and grease
  • Flushing sanitary towels and cotton buds and similar non-biodegradable products
  • Excessive use of kitchen sink grinder/disposals
  • Compromising the bacterial population by flushing pesticides, herbicides, bleach, lye, paints, solvents etc.
  • Damage to the tank or leach field by roots from trees and shrubbery
  • Construction over a tank or leach field, especially a parking lot, driveway, or building slab
  • Overloading a system with excess water, such as by connecting the input to a storm drain

Pollution risks

Raw sewage and byproducts of sewage treatment

The biggest single threat to the viability of the redevelopment project is the frequent appearance of coliform bacteria, and especially thermotolerant coliform bacteria, in a number of lakes. Presence of these bacteria suggest that there has been direct release of raw sewage into groundwater and/or surface waters, creating an immediate public health risk. The risk is the potential for human contact with water bearing pathogenic organisms, especially pathogenic bacteria. Because a poorly maintained septic system will release raw sewage into the environment, and because we have so many private septic systems in the area, a primary function of our department is monitoring of all water sources for possible sewage contamination. Long term planning must take into account the effects of byproducts of sewage treatment on the environment, especially ground and surface waters. The presence of coliform bacteria of fecal origin in a lake is strong evidence that there is a continuous release of raw sewage directly into the lake, that sewage reaches the lake via one more streams or groundwater feeding the lake, and/or from runoff into the lake from nearby surfaces.

Any system for processing sewage comes with an environmental cost. All systems produce the so-called greenhouse gases, methane and carbon dioxide. The presence of sulfates and nitrogenous compounds can respectively result in production of the toxic compounds hydrogen sulfide and ammonia. A centralized facility gives us greater control over release of some potentially harmful substances such as phosphates, which remain soluble in a septic system. Because phosphate is often the limiting nutrient in a local environment, its uncontrolled release by a septic system can lead to excessive plant or bacterial growth.

Of particular concern to our community are algae blooms and excessive growth of cyanobacteria, which commonly result from excess phosphate release. Both conditions are toxic to fish. In addition, eventual decomposition of the excess biomass usually depletes a water source of oxygen, also a detriment to a healthy freshwater ecosystem.

Farms and ranches

Pollution from farms and ranches poses little threat to water systems in Flabeetz County, as they are located at lower elevations over groundwater systems that are not contiguous with the groundwater beneath the Lakes Region. Our main concern has been pollution from feedlots that encroach upon the southeast corner of the area. Most of the level land in Bennett County is committed to farming and ranching. Cattle are trucked into feedlots in the areas where farming operations have proven impractical.

Bennett County feedlots

Most large animals that are slaughtered for human consumption are "finished" in arrays of high density pens called feedlots. Their diet is very rich, consisting mainly of corn supplemented by hay and sorghum. As with any feedlot, the diet and relative lack of mobility of the cattle makes the meat more tender and produces "marbling," or fat deposition, in the animal's muscles. Feedlot operators in Bennett County typically bring in cattle from the ranches further east at a weight of 600-700 pounds per animal. They typically bring them to a gross weight of 1000-1200 pounds over a time span of 4 months prior to slaughter.

The feedlots each harbor anywhere from two to ten thousand or more head. The large amount of waste generated in the feedlots poses a major potential pollution problem. The department is concerned about the odor from feedlots as well as soil and water contamination from large amounts of manure and urine. Feedlot operators are under federal order to collect and remove waste according to a rigid schedule, as the result of a lawsuit several years ago. Only one federal inspector is assigned to a several county area, however, so enforcement is spotty at best.

There has been animosity between residents of Flabeetz County and the cattle ranchers and feedlot operators. Eggstain is home to a growing community of environmental activists, including retirees, artists, and "back-to-nature" people who take a dim view of the operations to the east. Odor from the lots prompted the federal lawsuit. The community has placed the feedlots in the public eye with well publicized criticisms based upon the impact of the practice on the environment and on human health. Meat from cattle raised in feedlots has far more saturated fat than that of grass-fed cattle, for example. Local environmentalists have also publicized claims that feedlot cattle are fed anabolic steroids and antibiotics, which can threaten consumer health. Operators have denied such accusations and have threatened to take legal action seeking to suppress them and to obtain punitive damages.

Environmental degradation due to past farming practices

Although catfish farming has ceased in the regions to be redeveloped, past farming practices may be responsible for degrading the environment in the proposed recreational area. Catfish farmers in the Lakes Region do not treat discharged effluent. They rely on natural processes including algal and bacterial metabolism to eliminate most of the excess nitrogen, phosphorus, and organic matter. Pond sediments collect most of the end products. Contamination of drinking water from pond effluent is not a public health threat, as the waste products from fish do not transmit waterborne diseases of humans. Our primary concern regarding drinking water is esthetic, because chlorination to render drinking water safe does not necessarily remove unpleasant odors, taste, or color.

We are also concerned about the impact of bacterial contamination on the suitability of the lakes for recreational purposes. Planned recreational uses include boating, swimming, and fishing. Primary concerns for our department are total bacterial counts in the lakes and, especially, contamination with raw sewage.

Created by David R. Caprette (caprette@rice.edu), Rice University 20 Jul 07
Updated 23 Feb 16
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