Why Test for Bacteria using BARTs

• Water Well Operators
  Water wells are a “site unseen” operation. The extent of any visible fouling is limited to camera logs down the well or obvious fouling of filters and lines downstream of the well head. Often, the bulk source of all of the biological activity is outside of the well screen and not visible. What is visible is the “tip of the iceberg” which is the colloidal structures floating in the well water column (well snow), encrustations, tubercles and slimes attached to the walls and screens of the well and as deposits in the bottom of the well. Detecting even the most aggressive bacteria under these conditions is not simple. The bacteria often have to be “tricked” by changing the normal operational procedures for the well in order to be able get them into the water so that they can be detected using the BART tests. Most commonly used of the BART tests are:
  IRB (where there are known iron problems);
  SRB (where there are anaerobic, black water and corrosion problems);
  SLYM (where there are slimes forming in and over the well casing, screen or pump); and HAB (if there is turbidity, odd odors, cloudiness, fluorescence and high organic loadings in the water).
• Water Treatment Plant Operators
  Water treatment facilities usually involve water that has become aerated, possibly filtered, disinfected, clarified and stored. It should be remembered that the BART tests are proofed against the possible effects of chlorinebased disinfectants by the inclusion of a neutralizer that is effective for concentrations of up to 5,000 ppm of chlorine (sodium thiosulfate pellet). In general, apart from the concern for the elimination of coliform bacteria from the water, there is little regulated limitation to the microbial loadings in potable, industrial and recreational waters. Consequently, the need to monitor nuisance microbes is more in the interest of the operator rather than regulatory compliance. Unfortunately, the common attitude that water should be free disenfranchises the ability of the operator to assure a maximum operational efficiency in favor of bulk acceptable water produced at the lowest cost. Biofouling causes many covert (and commonly negative) impacts which often go unnoticed until it is too late to effectively control and then radical “surgery” has to be performed to replace the fouled parts. Common problems relate to massive slime formations (SLYM and HAB are good for checking this), corrosion of equipment (SRB), encrustations in pipes, tanks and filters (IRB and FLOR), and sudden fluctuations in water quality (HAB, SRB and DN). Fluctuating nitrate problems could be related to changes in the biofouling with a greater probability of nitrate expression in waters high in oxygen and low in organics. The organics would trigger a greater rate of enitrification particular under a suppressed oxygen regime. Routine use of BART tests in the ongoing operations of the treatment plant can allow earlier control of potential serious biofouling events.
• Bottled Water Plant Operators
  Bottled water represent a growing fraction of the consumed water since it reflects a superior product in the minds of the consumer to potable water supplies provided by local agencies. While ozonated and carbonated waters do have the microbial loadings suppressed to varying degrees depending upon the techniques employed, there is still a potential for the water to degenerate as a result of microbiological activity. Most commonly, this will take the form of clouding, deposits, tastes and odors. If these events occur when the product is already with the distributor or final retailer, then this would have serious consequences for the bottling company. Quality assurance and quality control can be achieved using the BART tests to determine that the source water is not fouled with aggressive bacteria and that the ozonation or carbonation has effectively acted as a disinfectant to suppress the nuisance microbes.
• Environmental Managers
  The largest biomass by far on Earth belongs to the microorganisms. This group is not sitting there passively while the biota (animals and plants) quietly does all of the “work.” Microorganisms are ubiquitous and functionally active whether they are in the human body (90% of the cells in the human body are microbial cells), in soils, waters, oil and gas, muds and sedimentary rocks. Environmental managers face the task of “managing” the environment and it is essential that the role of microorganisms in that environment be recognized. The BART tests offer the potential to take “snapshots” of the population of the various components in the microbial biomass that can have a significant impact on the environment of concern.
• Sanitary Landfill Operators
  There are a number of microbial challenges faced by sanitary landfill operators simply because of the highly organic nature of the fill materials deposited in the landfill. In going down through a landfill, there are a series of stratified activities predominantly microbial in form. These include (going from the top down):
  • Surface growths on the redox front dominated by methanogenic bacteria that are able to degrade methane.
  • Biogas generation zone in which methanogenic bacteria are very active producing copious quantities of methane.
  • Drainage systems in which bacterial activity causes the generation of thick plugging slimes (dominated often by SRB and SLYM bacteria). Should these growths get too aggressive, then there could be reduced permeability that would lead to the water mounding in the landfill and breaking out through side erosions.
  • Leachate outflows from the drains. Very aggressive aerobic activity is likely to occur around the redox fronts at these sites leading to radical nitrification (nitrate production) and heavy slime growths (dominated by HAB, SLYM, FLOR and IRB).

Both the functionality and stability of sanitary landfill operations can be severely compromised by aggressive microbial activities. An ongoing monitoring of these nuisance microbial groups using the BART testers can aid in predicting and controlling problems before they become uncontrollable.

• Operators of Recreational Waters
  These waters range from spas, swimming pools, hot tubs and beaches. With these waters there is a primary concern to reduce the hygiene risks to the users by the routine examination for coliform bacteria. However, there are other problems particularly with hot tubs, swimming pools and spas that are caused by other nuisance bacteria that can be detected using the BART tests.

  The effects of the nuisance bacteria would fall under the categories of reducing plant efficiencies, reducing water quality, and generating unacceptable slime growths. There are both economic and user acceptability issues involved in the microbial biofouling problems which can be monitored and managed using the BART testers.

• Irrigation Operators
  Vast volumes of water are used in the irrigation industry. This water is subjected to radical changes in pressures and flow rates often under increasingly oxidative conditions. Such shifts in conditions can cause a focusing of microbial slime growths within the system and nozzles that can radically reduce efficiencies and increase operating costs. Most commonly, the SLYM and IRB are likely to dominate under low iron and high iron conditions respectively. If there is a low oxygen concentration in the water, high sulfates or hydrogen sulfide “rotten” egg odor, black water), then the SRB may be dominant in the irrigation system. Cleanliness and sanitization of the equipment (confirmed by the routine use of the BART tests) is likely to pay dividends through improved efficiencies and higher quality water for irrigation.
• Hazardous Waste Site Operators
  While these sites may be very hazardous to humans, the environments created may be very conducive to extensive microbial activity. Such activity can be related to the rates of biodegradation and bioaccumulation activities being generated by the naturally attenuated consortia active at the site. Additionally, the operation of treatment facilities, injection and recovery wells, distribution lines and storage tanks can all become severely compromised. For example, returning treated water via the injection wells often becomes highly aerated. Upon injection, a redox front forms around the well in which bacterial slimes grow causing erratic losses in permeability. For the operator of hazardous waste sites, the BART tests provide a simple monitoring tool to determine the level of bacterial activity occurring when used routinely. Management of the site can subsequently be improved through this routine monitoring of the population levels (most simply monitored by the time lags observed).
• Cooling Tower and Heat Exchanger Managers
  As a matter of routine, water is used as the heat sink in many processes. The heat in that water is removed to the air (e.g., cooling tower) or to a greater volume of water (e.g., heat exchanger). For the heat to move efficiently in the transfer from the water to the receiving medium, there should be no interferences. Biofilms (slimes) forming at these interfaces can severely reduce this heat exchange in several ways. Failure to control these biofilms can be expensive due to losses in the process efficiency that causes equipment to fail to meet specifications. Controlling the biofilms is usually achieved by the application of biocides. By the routine testing of the waters using the BART tests, the effectiveness of the biocides in suppressing the biofilms can be determined conveniently and easily.