Municipal Water

Drinking water comes from surface water and ground water. Large-scale water supply systems tend to rely on surface water resources, and smaller water systems tend to use ground water. Surface water includes rivers, lakes, and reservoirs. Ground water is pumped from wells that are drilled into aquifers (natural reservoirs below the earth's surface).

Everytime it rains, the wastes produced by man are washed from the air and, depending on the rate of precipitation and solubility of the wastes, are carried to and into the soil and underground water supplies or are carried by surface runoff into our surface waters. It is, therefore, safe to conclude that all products and wastes produced by humans are present at some time in the water sources from which we derive our drinking water: our public water supplies.

Robert Baumann maintains that we can conclude with absolute certainty that the water we use has been, and is being, exposed to all products produced by humans. In order to assess their effects on the use of the water as a source of drinking water, all such constituents may be classified in one of four general classifications depending on whether their presence in water would be:

The placing of a particular constituent of water into one of these classifications will depend on the concentration of the constituent and its probable effects (health, esthetic, synergistic, economic, etc.) on the water's use:

Fluoride at a concentration of 1 mg/L is desirable in water since it contributes to reduction in the DMF (Decayed, Missing, and Filled) incidence of tooth decay, but at 10 mg/L it must be reclassified into the impermissible classification since it then contributes to mottling of teeth.

Epidemiologists link cryptosporidium to 11 U.S. waterborne illness outbreaks since 1984. But various studies say between 900,000 to two million Americans per year are sickened by crypto or other waterborne pathogens.

Cryptosporidium is a protozoan parasite that moves through the environment in tiny egg-shaped capsules called oocysts. The strain that affects humans, C. parvum, reproduces in the intestines of mammalian hosts that have ingested the oocysts from food, water or close contact with already infected persons or animals. The oocysts are typically three to seven microns in diameter, about one-twentieth the typical thickness of a human hair strand.

Each oocyst contains four crypto spores, which burst through the thin cell wall, then rapidly reproduce. The new parasites infect the host or form new oocysts and move on through the digestive or respiratory systems. For people with normally functioning immune systems, the infection, called cryptosporidiosis, can trigger up to two weeks of severe abdominal cramps and diarrhea. But for AIDS patients, those on chemotherapy and others with weakened immune systems, the risk is much greater. Instead of experiencing a painful bout of what is often misdiagnosed as stomach flu, they can get sick and often are too weak to recover. There is no known treatment. As the AIDS epidemic spread in the 1980s, cryptospiridiosis became a commonly reported cause of death.

There are specific microbial pathogens, such as Cryptosporidium, that are resistant to traditional disinfection practices. In 1993, Cryptosporidium caused 400,000 people in Milwaukee to experience intestinal illness. More than 4,000 were hospitalized, and at least 50 deaths have been attributed to the disease. There have also been cryptosporidiosis outbreaks in Nevada, Oregon, and Georgia over the past several years.

Amendments to SDWA in 1996 require EPA to develop rules to balance the risks. It is important to strengthen protection against microbial contaminants, especially Cryptosporidium, and at the same time, reduce potential health risks from disinfection byproducts. The new Interim Enhanced Surface Water Treatment Rule and Stage 1 Disinfectants and Disinfection Byproducts Rule are the first of a set of rules under the Amendments.

EPA's Science Advisory Board concluded in 1990 that exposure to microbial contaminants such as bacteria, viruses, and protozoa (e.g., Giardia lamblia and Cryptosporidium) was likely the greatest remaining health risk management challenge for drinking water suppliers. Acute health effects from exposure to microbial pathogens is documented and associated illness can range from mild to moderate cases lasting only a few days to more severe infections that can last several weeks and may result in death for those with weakened immune systems.

National Primary Drinking Water Regulations (NPDWRs or primary standards) are legally enforceable standards that apply to public water systems. Primary standards protect drinking water quality by limiting the levels of specific contaminants that can adversely affect public health and are known or anticipated to occur in public water systems.

Figure XIII-1 shows the attributes of three groups of pathogens of concern in water treatment, namely bacteria, viruses and protozoa

Figure XIII-1: Attributes of the Three Waterborne Pathogens of Concern in Water Treatment

Organism	Size (µm)	Mobility	Point(s) of Origin	Resistance to Disinfection	Removal by Sedimentation, Coagulation and Filtration
Bacteria	0.1-10	Motile, Nonmotile	Humans and animals, water and contaimanted food	Type specific-bacterial spores typically have the highest resistance whereas vegetative bacteria have the lowest resistance	Good, 2 to 3-log removal
Viruses	0.01-0.1	Nonmotile	Humans and animals, polluted water, and contaminated food	Generally more resistant than vegetative bacteria	Poor, 1 to 3-log
Protozoa	1-20	Motile, Nonmotile	Humans and animals, sewage, decaying vegetation, and water	More resistant that viruses or vegetative bacteria	Good, 2 to 3-log

The Interim Enhanced Surface Water Treatment Rule applies to public water systems that use surface water or ground water under the direct influence of surface water (GWUDI) and serve at least 10,000 people. In addition, states are required to conduct sanitary surveys for all surface water and GWUDI systems, including those that serve fewer than 10,000 people.

The Interim Enhanced Surface Water Treatment Rule amends the existing Surface Water Treatment Rule to strengthen microbial protection, including provisions specifically to address Cryptosporidium, and to address risk trade-offs with disinfection byproducts. The final rule includes treatment requirements for waterborne pathogens, e.g., Cryptosporidium. In addition, systems must continue to meet existing requirements for Giardia limblia and viruses. Specifically, the rule includes:

The rule with tightened turbidity performance criteria and individual filter monitoring requirements, is designed to optimize treatment reliability and to enhance physical removal efficiencies to minimize the Cryptosporidium levels in finished water. Turbidity requirements for combined filter effluent will remain at least every four hours, but continuous monitoring will be required for individual filters. In addition, the rule includes disinfection profiling and benchmarking provisions to assure continued levels of microbial protection while facilities take the necessary steps to comply with new DBP standards.

States have two years from publication to adopt and implement the requirements of this regulation. Simultaneous compliance with the Stage 1 Disinfection Byproduct rule, promulgated at the same time, will be achieved as follows:

Public water systems that use surface water or ground water under the direct influence of surface water, either in whole or in part, and serve a population of 10,000 or more generally have three years form Federal promulgation to comply with requirements of this rule, except for disinfection profiling and benchmarking, which require systems to begin sampling after three months. In cases where capital improvements are needed to comply with the rule, States may grant systems up to an additional two years to comply.

EPA estimates that implementation of the Interim Enhanced Surface Water Treatment Rule will:

Improve public health by increasing the level of protection from exposure to Cryptosporidium and other pathogens (i.e., Giardia, or other waterborne bacterial or viral pathogens) in drinking water supplies through improvements in filtration at water systems;

The total annualized national cost for implementing the Interim Enhanced Surface Water Treatment Rule is $307 million. EPA believes that the benefits exceed the costs. The rule will result in increased costs to public water systems for improved turbidity treatment, monitoring, disinfection benchmarking and covering new finished water reservoirs, as well as State implementation costs.

EPA estimates that 92 percent of households will incur an increase in their water bill of less than $1 per month; seven percent of households will incur an increase in their water bills of between $1 - $5 per month; and less than one percent will incur an increase of between $5 and $8 per month.

The projected capital cost of the new rule is $759 million. This compares to a capital cost to install membranes at all U.S. municipal treatment plants of $30 billion. The $759 million on one hand includes more than just membrane systems. On the other hand, this cost is just the incremental increased capital cost over what would have been invested without the rule. Since membranes are now competitive with sand filter installations the incremental additional cost would be zero where a new sand filter installation already would have been required. The rule is based on the ability of rapid sand filter systems to meet the efficiency requirements when enhanced by chemical additions, coagulant improvements, settling improvements, and other operational improvements as well as filtration improvements.

The requirement for chemical additions at some plants in order to meet the requirements creates a growing chemical market to comply with the new rule on disinfectants and disinfection byproducts. It sets goals for chlorine at 4 mg/l and sets goals for a number of other compounds as well.

To comply with the Surface Discharge Water Act (SDWA) regulations, the majority of Public Water Systems (PWSs) use some form of water treatment. The 1995 community Water Systems Survey (USEPA, 1997a) reports that in the United States, 99% of surface water systems provide some treatment to their water, with 99% of these treatment systems using disinfection/oxidation as part of the treatment process (Figure XIII-2). Although 45% of ground water systems provide no treatment, 92% of those ground water plants that do provide some form of treatment include disinfection/oxidation as part of the treatment process.

Disinfectants are also used to achieve other specific objectives in drinking water treatment. These other objectives include nuisance control (e.g., for zebra mussels and Asiatic clams), oxidation of specific compounds (i.e., taste and odor causing compounds, iron and manganese), and use as a coagulant and filtration aid.

Alum and iron salts or synthetic organic polymers (alone, or in combination with metal salts) are generally used to promote coagulation.

Chlorine, chloramines, or chlorine dioxide are most often used to disinfect drinking water because they are effective, and residual concentrations can be maintained to guard against biological contamination in the water distribution system. Ozone is not effective in controlling biological contaminants in the distribution pipes.

The most commonly used disinfectants/oxidants are chlorine, chlorine dioxide, chloramines, ozone, and potassium permanganate. Chlorine is, by far, the most commonly used disinfectant in the drinking water treatment industry. Today, chlorine is used as a primary disinfectant in the vast majority of all surface water treatment plants, being used as a pre-disinfectant in more than 63% and as a post-disinfectant in more than 67% of all surface water treatment plants.

Iron and manganese occur frequently in ground waters but are less problematic in surface waters. Although not harmful to human health at the low concentrations typically found in water, these compounds can cause staining and taste problems. These compounds are readily treatment by oxidation to produce a precipitant that is removed in subsequent sedimentation and filtration processes.

Oxidation is commonly used to remove taste and odor causing compounds. Tastes and odors in drinking water are caused by several sources, including microorganisms, decaying vegetation, hydrogen sulfide, and specific compounds of municipal, industrial or agricultural origin. Disinfectants themselves can also create taste and odor problems. In addition to a specific taste- and odor-causing compound, the sensory impact is often accentuated by a combination of compounds. More recently, significant attention has been given to tastes and odors from specific compounds such as geosmin, 2-methylisoborneol (MIB), and chlorinated inorganic and organic compounds.

The U.S. uses more water than other countries, even those that are equally well developed. In the United States, significant amounts of water are used for lawn and garden sprinkling, automobile washing, and kitchen and laundry appliances, such as garbage disposals, clothes washers, and automatic dishwashers.

A typical U.S. family of four on a public water supply uses about 350 gallons per day at home. In contrast, a typical household that gets its water from a private well or cistern uses about 200 gallons for a family of four. Commercial and industrial businesses may also place heavy demands on public water supplies in developed countries.

According to the latest EPA inventory of U.S. drinking water systems, 91 percent of Americans are receiving their drinking water from community water systems which have not had any health-based violations that limit the amount of contaminants allowed in drinking water. This is an increase from 1993, when 79 percent of the systems reported no violations of health- based standards.

There are over 53,000 community water systems in the U.S., most of which serve fewer than 10,000 people each. About 15 percent of these systems (approximately 8000) provide drinking water for 90 percent of those Americans who get their water from a public water system.

The reuse of treated municipal wastewater is becoming more common as technology for purification improves and the cost and supply of fresh water climbs. The reuse of wastewater, as a concept, includes many treatment applications including - at its lease demanding - irrigation, through cooling tower makeup and boiler feed to complex treatment allowing recycling the wastewater in an industrial process ("closed loop"). There is no general treatment scheme for reclaimed water facilities. The optimum treatment must be determined based on the characteristics of the wastewater stream, whether of municipal or industrial origins.

Three examples of treatment of industrial wastewater are cited below to demonstrate the technological creativity now being employed.

Case History 1 - Hyperion Treatment Plant, City of Los Angeles. Design capacity, 18.4 m³/second (292,000 gpm), with treated wastewater discharged to the Pacific Ocean. California statutes (Title 22) permit wastewater to be further treated to achieve a turbidity of >2 NTU, disinfected, and used for irrigation of municipal parks, golf courses and for industrial needs. The West Basin Recycling Facility, with an ultimate design capacity of 4.4 m³/second (1162 gpm), will be the largest water recycling facility in the U.S. The present plant takes 0.66 m³/second (174 gpm) secondary effluent from Hyperion and treats it to Title 22 standards, however refineries were unable to switch to reclaimed water because of the high levels of ammonia. (Hyperion Treatment Plant does not nitrify.) The presence of ammonia is unacceptable since it is highly corrosive to Admiralty Brass used in the refinery heat exchangers. In response the recycle water to these facilities was further treated in nitrifying systems, Degremont's "Biofor" system, guaranteed to remove 90 percent of influent ammonia. Breakpoint chlorination is used to remove the remainder of ammonia.

Case History 2 - In this Florida power generating facility tertiary effluent (treated urban wastewater) is used, after further treatment, as boiler feed. The makeup demineralizer system consists of softening/clarification and gravity filtration with provisions for feeding lime, soda ash, alum, sodium hypochlorite and polymer. Filter effluent is further processed through activated carbon beds and cartridge filters before being fed to the RO, after which it enters a four bed demineralizer. Seasonal Total Nitrogen levels and turbity of the secondary effluent, under normal circumstances may be considered acceptable for RO systems. However, values for TOC and BOD were not included in the design analysis. The wastewater was chlorinated to maintain a 1.0 Cl2/l residual. This free chlorine rapidly dissipated as it reacted with the ammonia and organics in the wastewater, resulting in a zero chlorine residual by the time the wastewater entered the pretreatment system, providing an ideal environment for biological growth.

The clarifier-softener's operation at a high pH was having no effect on the organic matter, which is typically removed at lower pH conditions. Consequently the clarifier was converted to an alum clarification mode, operating at pH 6.0-6.2 using 85 mg/l aluminum sulfate to coagulate the high concentration of colloidal organic matter in the influent. As a result the SDI was improved to the 2.8-3.5 range, allowing trouble free RO operation.

Cast History 3 - Wastewater produced from an oil field in Southern California forms 90 percent of the oil pumped from the reservoir. Historically, produced water has been treated for discharge or re-injected into the oil field. In the present case a 50 MW cogen plant, the water is treated for power plant uses, notably cooling tower makeup and boiler feed. The steam produced is injected into the oil reservoir to enhance oil recovery. Average plant water use is approximately 200 m³/hr (53,000 gph). The first stage of treatment is air flotation IAF) followed by lime softening, with parallel silica removal in a high rate clarifier. Most of this clarified softened water (130 m³/hr-34,000 gph) is used in cooling tower makeup. The remainder is filtered, passed through RO units and two bed ion exchange units. Silica removal is achieved by dosing magnesium chloride to the unit.

It was originally intended that the clarifier effluent, after gravity filtration, would be adequate for the RO units. Unfortunately, while the turbidity was typically low, the SDI's were above 6.0, leading to increased membrane fouling. The high SDI's were found to be due to 1-10 µm sized particles of aluminum silicate and silt, present in the produced water, and not removed by either the IAF or clarification upstream. The SDI's were finally reduced by installing pressure filtration with volcanic pumice as the media, downstream of the gravity filters. Poly aluminum chloride is added directly upstream of these filters as coagulant. The system has now been working for over seven years.

By December 31, 1997, a worldwide total of 12,506 desalting units with a total capacity of 22,800,000 m³/d or 6,030 MGD (US) had been installed or contracted. This represents 1,275 units and 2,350,000 m³/d or 621 MGD (US) capacity more than at the end of the previous two years. In comparison with the period (1994/1995), the number of units increased by 27.5 percent, whereas the capacity increased by 55 percent. This is due to the fact that larger RO plants were contracted in a number of countries other than those from the Arabian Peninsula. A considerable portion was contracted in the USA.

This compilation was prepared by Klaus Wangnick for the International Desalination Association.

India is a growing market due to the need to desalt brackish and wastewater. The Middle East market was down during the 1996 and 1997 period but is rebounding in 1998. Spain was the leader in the 1996/97 period relative to seawater treatment.

Ionics had the largest contracted capacity over the period (240,000 m³/d). Degremont was second and Fisa third. Other leaders are Camp Dresser, Kurita, Metito and Sidem. With regard to seawater plants Fisa was the largest supplier but mostly supplied MSF whereas Degremont was second with mostly RO plants. Cadagua was next with mainly RO plants. Sidem and IDE sold mostly ME plants.

Dow Filmtec was the RO membrane leader with a capacity of 260,000 m³/d. DuPont was second with 200,000 m³/d and Hydranautics third with 150,000 m³/d. DuPont's biggest market was seawater where it sold 95 percent of its membranes for desalination.

Reverse osmosis has gained popularity in seawater treatment applications worldwide, mostly in areas where brackish water is scarce (such as the Middle East, South East Asia and parts of the Mediterranean).

Capital costs remain a prime disadvantage of reverse osmosis plants compared to brackish facilities.

Proper pretreatment filtration devices and cutting-edge membrane technologies are two items that will enable new seawater plants to operate efficiently. Long-term costs will then be minimized and in many cases remain lower than most alternative systems.

Passing feed water through the actual RO membrane is by far the most expensive operation in an RO seawater plant, both in capital and long-term costs. The feed water would be introduced under pressure into pressure vessels containing the membranes. These membranes provide separation of selected monovalent and divalent ions. Factoring in an average life-span of three to seven years (based on the amount of usage and the quality of the feed water), the only long-term cost will be changeout of the RO element. With the proper operation, replacement of the pressure vessels in which the element is contained will be unnecessary. Reducing or eliminating the need to replace these expensive vessels decreases cost considerably.

Most large desalination plants are installed in dual-purpose power and water stations in order to make the best use of energy from fuel. Moreover, seawater intakes can be constructed to serve both facilities.

In the past, reverse osmosis was used mainly for single-purpose plants, while multi-flash distillation (MSF) was traditionally the technology most widely used for large dual-purpose plants, although multi-effect distillation (MED) had since increased its market share.

Due to the increase in energy costs during the last years, the RO process is now emerging as the most energy- and cost-efficient desalting system, as its specific prime energy consumption is significantly lower. Even greater energy efficiency is realized when RO system designs use energy recovery devices on high pressure brine reject streams. However, there is still a potential for further considerable increases of specific water production in dual-purpose plants.

RO provides a unique advantage over integrated power and water cogeneration plants since RO is the only commercial desalination process available on an industrial scale which can make use of both electricity and process heat as the main drive power for desalting seawater. This is achieved by driving the RO feed pumps either by electric motors or by condensing steam turbines.

Presently, the most efficient way to cover the steam demand for desalination is through steam produced by a heat recovery steam generator at the exhaust of a combustion turbine power generation cycle. The generated electrical power is used to operate electrically driven RO units (ROE), part of it being available for export to the grid.

Since some of the major consumers of electrical power in the RO plant, namely the RO feed pump drives have been replaced by steam-turbines, the specific electrical power consumption is less than the specified power consumption of MSF/MED plants, the reason being less feedwater and brine need to be pumped to and from the RO plant due to the much higher conversion ratio.

The capital cost of steam-driven RO units remains lower than comparable MSF/MED units as a result of considerable savings in the RO plant.

The feed-to-product ratio of the RO plant is less than 2.5:1, whereas in distillation plants, the ratio varies between 7-12:1, thanks to using feedwater as cooling water. Consequently, the required seawater intake and brine outfall structure for an RO plant is much smaller than for MSF/MED plants.

The performance ratio of a steam-driven RO unit is approximately 50 MSF/MED:7/21. Such RO units produce two to three times as much water as MSF/MED plants using the same amount of steam energy.

The power/RO plant allows a better match of power and water demand, eliminating the traditional MSF ratio of 8-10 MW of export power for one mgd of product water since all the generated power and process heat can be used in the RO plant for desalination.

Power from the grid can be imported to secure continuation of part of the water production in case of shutting down a power generation unit.

The power/RO cogeneration plant offers additional flexibility of operation by its increased ability to "follow" daily and seasonal power and water demands.

The RO technology has reached the point where life-cycle costs are competitive with traditional MSF plants for single- and dual-purpose plants of any size. The introduction of this new power/RO cogeneration concept has positioned the RO process as the optimum technology for power and water cogeneration plant installations, since the RO process is the only desalination process which can make use of both electricity and process heat as the main drive power for the desalination of seawater. Consequently, using RO, large quantities of desalted water can be provided to regions where no further electrical power is needed.

An economic analysis done by Salzgitter Anlagenbau GmbH has shown that the product water cost form the power/RO cogeneration plant can be reduced by 15-20 percent as compared to power/MSF plant due to much better utilization of the specific fuel energy.

By using waste- or low-grade energy from the thermal cycle of the power plant for seawater distillation, the water in this case can be produced at a lower cost than potable water from the municipality, where a charge for wastewater disposal is included in the price.

The produced distillate from water desalination can therefore economically substitute the use of municipal water.

In 1990, the electric power company SK Energy installed a coastal coal-fired CHP plant south of Copenhagen. This facility is one of the most advanced and efficient of its type in the world. The electric power generation capacity is 250 MW produced with a coal-fired (oil as backup) boiler and steam turbine. The district heating has a capacity of 330 MW. The plant uses a multi effect process and supplies boiler feedwater makeup and water to the desulfurization unit.

Repowering of existing coastal power stations with integration of seawater desalination is foreseen as a highly probable means of meeting some of the expected shortfall between water demand and supply in Southern California by the turn of this century. Using base steam cycles typical for twenty to thirty year old power plants, a number of cases have been evaluated by Fluor Daniel with repowering using advanced gas turbines together with seawater desalination based on reverse osmosis, low-temperature multiple effect distillation (LTMED) and high-temperature multiple effect distillation (HTMED).

As seawater desalination is most economical when integrated with power production, and permitting requirements would stand in the way of new power/desalination plants, it is highly likely that the desalination facilities in Southern California would be tied to one or more of the existing coastal power stations, some of which are excellent candidates for repowering in the mid- to long-term future. One such existing coastal plant, the Mandalay Generating Station, in Oxnard, CA.

RO has the lowest energy cost and the advantages of proven technology, process simplicity and the greatest potential for further lowering of costs. In a repowering situation, RO has the added advantages of independent operation and of not requiring any new equipment for the steam cycle. In view of these considerations, they believe that RO will remain a strong contender for any large-scale desalination application in Southern California, and should be carefully evaluated as an alternative to thermal desalination processes.

It is estimated that by 2010, the total water demand within San Diego County will reach 900,000 acre-feet per year. However, the current imported water supply will provide only 690,000 acre-feet, with local water supply yielding another 60,000 acre-feet. (1 acre-foot = 326,000 gallons, = 1234 cubic meters).

To address the projected shortfall of 150,000 acre-feet, water repurification is one of the alternatives being considered. Several health effect studies were conducted since 1983, with the conclusion that the health risk associated with the use of repurified water as a raw water supply is less than or equal to that of the existing City raw water supply. The repurification plan developed for San Diego consisted of the following five steps:

The broad classes of contaminates in reclaimed wastewater that are of concern to public health are microbiological contaminates, organic contaminates and heavy metals. For the San Diego project the levels of total dissolved solids (TDS) and nutrients such as nitrogen and phosphorus are also important in order to maintain a stable reservoir quality. These considerations led to the adoption of the reverse osmosis process as the foundation of treatment, offering the best overall removal of organic, metals and TDS, and having the potential for removal of all classes of microorganisms as well.

Three pretreatment alternatives were evaluated, lime clarification, ferric chloride clarification, and microfiltration. MF is a low pressure membrane filtration process effective in rejecting microorganisms and particulate matter from the water and was selected for this project. Compared to the other two alternatives, it is more cost effective, requires a smaller footprint area and produces a superior effluent water quality in terms of colloidal concentration, which in turn is likely to reduce RO membrane fouling. Other pretreatment usually required for RO feedwater includes pH adjustment and antiscalent addition.

Disinfection - Three disinfection procedures were considered, chlorine, ultraviolet irradiation, and advanced oxidation. Advanced oxidation was selected, together with free chlorine for added disinfection credit in the conveyance pipeline to the reservoir. The water will be dechlorinated before discharge to the receiving reservoir.

Based on the above described feasibility study and the developed AWT the California Department of Health Services issued a conditional approval for the project. To assure a successful design and performance of the full scale 23 MDG (87,000 m³/d) AWT plant a pilot study was approved. This will also allow qualifying membrane manufacturers to be included in the final bidding. The pilot-scale evaluation program is currently underway at Aqua 2000 Research Center in Escondido, CA.

Bottled water has been the fastest-growing beverage category this decade, making up 11.1 percent of the total refreshment beverage market. In the past six years, sales have risen 26 percent and are expected to maintain an annual growth rate of 8 percent.

The industry reported sales of $4 billion in 1997, up from $3.6 billion in 1996. That translates into 3.4 billion gallons of water compared to 3.1 billion in 1996. Individual consumption of water has grown from 5.2 gallons in 1985 to 12.7 gallons in 1997.

In 1997 1.2 billion gallons of bulk water were delivered to homes and offices in the United States, up 6.7 percent from 1996. Sales of five-gallon containers grew 6 percent in 1998. Although bulk water sales have been strong, its market share has been declining. Bulk sales captured 37.5 percent of the market in 1998, down from a peak of 45 percent in 1989.

Market factors include reduced consumption of alcohol and soft drinks in the U.S. leading to higher consumption of fruit juice and bottled water in the U.S. Two distinct but seldom reported trends are the increase in beverage consumption - particularly water and water-based juices by people who favor salty snacks and coffee (a diuretic) - and negative consumer perceptions of tap water quality.

The water treatment industry has become used to combining the terms point-of-use (POU) and point-of-entry (POE). While these two technologies do operate under similar principles, it's important to understand not only the differences in products and prices for each method, but also the different distribution, sales techniques and intended markets for both types of systems.

The fundamental difference between POU and POE is the increased production and capacity volume of a POE system.

Component synchronization systems and features such as filter and membrane backwashing and fail-safe alarms may require the use of electronic controllers and other advanced operating equipment. As POE water treatment components become larger and more intricate, more parts are needed to support the higher flow rates. The result is usually a more complex system.

A second fundamental difference is POE's increased treated-water storage capacity - often in the hundreds of gallons. Providing the surge capacity for peak water-usage intervals means creating individual application requirements for storage-tank sizing and pressurizing systems.

Some POE systems contain ozone, backwashing, multi-media filtration, carbon, particulate and specialty filtration, with ultraviolet (UV) and sometimes reverse osmosis (RO) in the same application. This "all-in-one" multi-barrier approach can end up appearing costly to the customer and the dealer, but is actually much less expensive than custom design and build costs that are otherwise incurred with each new application.

Niche categories include high-end homes, livestock operations, nursing homes, equestrian centers, food-processing operations, retail bulk-water stores and bars and restaurants.

POU sales accounted for 30 percent of the total residential market in 1997 and are expected to grow faster than the industry average throughout 2004, as increasing interest in cleaner drinking water fuels sales of high-level treatment units like RO and UV.

By 2004, the POU equipment market is projected to account for 33.8 percent of the total residential market.

Not all POU equipment is expected to grow in popularity. Filter pitchers, separate from other POU sales, which commanded 16 percent of the market in 1997, will account for only 17 percent of the market by 2004. Increased interest in more advanced water treatment systems will result in flat growth rates for pitchers.

The slowdown in filter pitcher popularity is good news for dealers. As consumers upgrade their drinking water systems, they are likely to buy undersink RO and UV systems. One reason for the shift is that the cost of membrane filtration is down and performance is up.

In 1997, the undersink market reached annual revenues of more than $100 million, and is expected to grow at seven percent to eight percent annually. The undersink market is a dynamic one, with constant shifts in end-user preferences. Dealers and manufacturers will have to stay abreast of technological improvements and changing consumer needs to stay competitive.

While taste and odor used to be primary concerns, now many Americans have their drinking water tested for contaminants that are not so easily detected. This surge of concern for drinking water quality has spurred the growth of undersink units as end-users move from using pitchers, which only remove chlorine and other taste and odor problems, to more sophisticated equipment.

Prices in the undersink water treatment market have been declining since 1996 due to increased competition. Dealers have been forced to lower their prices to maintain market share.

ROs have seen a drop in price of between 20 percent and 50 percent during the past two years, while carbon/sediment systems remain steady. Carbon/sediment treatment accounted for more than one-quarter of POU revenues in 1997. By 2004, this number should reach almost one-third of the market. However, some manufacturers are looking past carbon filtration.

Investments to improve municipal drinking water systems can be categorized in two major segments. One is new plants to serve expanded populations or to provide water treatment where none was provided before or two, replacement and upgrading. The capital cost of a 1 mgd filtration plant is approximately $1 million or $1.00/gal/day. Clarifiers, water treatment, chemical addition equipment, controls, holding tanks, pumps etc. are the bulk of the expenditure. Plant upgrades and replacements are less expensive than the original investment.

The new U.S. EPA regulations for all public treatment plants to remove Giardia and Cryptosporidium protozoa has created a huge market opportunity for fine filtration. Every system serving more than 50 people will be required to have an approved 2-barrier technology in place to assure at least a 4 log reduction in this protozoa. Existing systems with clarification, sand filtration and disinfection probably will meet the regulation requirements but there are thousands of small systems, mostly on lake water or well water, that must add equipment.

The most common technology. (Clarify, Sand Filter and Disinfect) is not the best for these protozoa, but every design engineer and city water department is familiar with it and will consider it as one of the options.

Bag filters, cartridge filters, and micro filtration membranes will all meet the 1 micron absolute filtration efficiency to deliver as much as a 4 log reduction in protozoa. One of these coupled with ozone plus chlorine will meet the new EPA standards very comfortably.

The drinking water market will be very active for at least the next 5-10 years installing these protozoa barriers. There will be many plants every year in every state buying equipment, and as a first approximation the geographic distribution will be proportional to the population.

Cartridges are used are used as prefilters upstream of water purification plants such as deionization and reverse osmosis.

Pall reports Giardia Lamblia and Cryptosporidium parvums are present in 67-95 percent of all surface water and have been detected in 39 percent of the drinking water supplies in the U.S. A low level of contamination can cause serious illness or death in individuals in high-risk categories (immunocompromised, cancer patients, children and elderly people).

Depending on the quality of the water source available, it may be desirable to use a filter such as Pall's micron AbsoLife filter for protection of the make-up water from cyst contamination.

The 1 micron AbsoLife filter has been tested and certified to NSF Standard 53 to Drinking Water Treatment Units by NSF International.

Prior to the 1 micron AbsoLife filter certification, systems, not an individual component, such as a filter, were certified under NSF Standard 53. The 1 micron AbsoLife filter was the first filter listed as meeting NSF Standard 53 as of December 15, 1997.

The AbsoLife filter cartridge has a unique melt-blown media providing high removal efficiency of 99.98 percent and a long-term efficient service life. (Note: the tests used by Pall to give the filter the 1 micron rating are for a removal efficiency of 99.98 percent and the tests used by NSF are to certify removal efficiency of > 99.95 percent).

The filter is sanitizable with common chemical sanitization agents and is steam sterilizable.

The 1 micron AbsoLife filter can be used in applications in which there is a risk that cysts are present, such as make-up water from a municipal source.

Both the bottled water industry and the home treatment segment are rapidly growing areas. Cartridge filters are used in both. In the home treatment arena growth is seen in all areas. These include point of entry (POE), faucet-mount, undersink and pitchers. The pitcher sales will eventually decrease being replaced by undersink or POE filtration.

In 1997 1.2 billion gallons of bulk water was delivered to homes and offices in the United States up 6.7 percent from 1996. Also in 1997 sales of $4 billion were reported for single-serving bottles, the fastest growing segment of the market. Individual consumption of water has increased from 5.2 gallons in 1985 to 12.7 gallons in 1997.

Cartridge filtration is used by the bottled water industry to remove cryptosporidium cysts. These cysts represent a health hazard and do not respond to routine chlorine treatment.

For the process configurations required to treat large volumes in the bottled water industry, CUNO offers the Polypro® 060GP pleated filter cartridge. With an area of 7 ft2, this filter offers high flow rates and "absolute" particle retention efficiencies. It has passed the NSF Standard 53 test and is recommended as an absolute barrier to Cryptosporidium for all bottled and potable water applications including city water used to wash bottles for spring water.

For cartridge sanitation, either steam sterilization at 121°C or hot water between 65°C to 95°C for 30 minutes is recommended. Chemical disinfection alone is not effective because cysts will survive treatment.

Activated carbon filters are widely used in water treatment, both in the form of granular tank-type filters, and as finely divided powders incorporated into cartridges. The granular filters must be backwashed periodically, and the cartridges cleaned or replaced from time to time.

If the water to be treated with granular activated carbon contains a high concentration of organic matter or hydrogen sulfide, the carbon ultimately becomes saturated and can adsorb no more of these impurities. Some success has been reported in treating the beds with high dosages of household hypochlorite bleach to "burn off" the adsorbed impurities, and extend the life of the bed. However, in time it usually becomes necessary to replace the activated carbon bed.

If the activated carbon is used for the removal of chlorine, some of the carbon is actually consumed in the process. In such cases, small amounts of carbon must be added to the bed to replace that which is lost.

Graver Geneva Industrial Carbon filters simultaneously reduce chlorine, taste, odors and organic chemicals while providing the particulate filtration and dirt holding capacity of efficient sediment filters. A 15 micron polypropylene spun-bonded prefiltration medium extends the carbon block dirt holding capacity and service life. These filters are optimized for applications where both sediment and activated carbon filtration are required.

The radial flow of a Geneva Industrial Carbon filter is said to provide a higher flow rate and lower pressure drop than GAC filters. Unlike GAC filters, Industrial Carbon filters will not channel or bypass, due to the extreme uniformity of their compressed activated carbon structure.

Available in a standard size of 2.5" diameter and 9.75" length, Geneva Industrial Carbon filters are ready for installation into standard filter housings.

The average adult consumes about 1.2 quarts of water every day, either as tapwater or other beverages. Relative to body weight, children under 5 years consume twice as much water as adults, and women consume 20 percent more than men. Food is also a major source of water. Tomatoes are 90 percent water, meats between 50 percent and 70 percent, and bread averages 35 percent. The water in our foods comes from the same sources as the water that we drink.

In the United States, drinking water is cheap. It usually costs between 50 cents and $2.00 per 1,000 gallons, depending on where one lives. Milk, soft drinks, orange juice, and bottled water can cost up to several thousand dollars for 1,000 gallons, and liquor costs tens of thousands of dollars for the same quantity.

The average American uses between 50 and 150 gallons of water each day, 29 percent for flushing the toilet; 39 percent for bathing, laundry, and dish washing; 30 percent for swimming pools and watering lawns and gardens; and a mere 1.5 percent for drinking and cooking. Only 0.5 percent is actually used for drinking.

In the United States, about 450 billion gallons of water are withdrawn from the earth every day. That translates into 2,000 gallons for every person in the country. Most of this water goes to industry (58 percent), but much of it is reused. The next biggest use is irrigation. California withdraws far more water than any other state; Texas is second. Along with New York, these three states account for 30 percent of public water withdrawal in the United States.

About 100 billion gallons of water daily are "consumed," or not immediately reusable. More than 80 percent of all the fresh water consumed puts an average of 2.9 feet of water per year on every irrigated area in the United States. The consumption of the 17 Western States is 80 percent of the total, but these states have only 30 percent of the population. Most consumption is for irrigation. Industry's consumption throughout the United States is eight percent of the total; the public sector consumes about 4.5 percent of the total; commercial uses such as car washes, laundries, etc. account for 2.5 percent; and rural consumption amounts to only four percent.

Most pricing practices for water encourage use, with lower prices per incremental gallon. Only recently have pricing strategies begun to change, so that if more water is used, the higher the price is per gallon. Water prices will also increase generally, largely because all the cheap sources of drinking water have already been developed. To meet the growing demand for water, communities will have to tap sources that are farther away or are polluted, then pay to have the water purified and piped long distances.

Drinking water is distributed to consumers by local water utilities located throughout the United States. These utilities pump raw water from rivers, lakes, and underground sources, treat it, then send it through an underground pipework system to the community. There are about 59,000 public or community water utilities, about 40 percent of them investor owned and the rest operated by local municipalities. The federal government does not operate water treatment and distribution systems except for those on federal land such as national parks, etc. In addition to the public water systems, about 40 million Americans rely on individual private wells, and there are about 150,000 non-community water systems serving transients such as guests at hotels or resorts.

The vast majority of the 59,000 water systems are small, that is, they serve relatively few people. For instance, over 90 percent of the utilities serve less than 10,000 people, 66 percent serve less than 500 people, and about 35 percent serve less than 100 people. At the other extreme, there are only 45 water utilities that each serve over 500,000 people.

Producing drinking water is a major industry. The replacement value for all water treatment facilities is nearly $200 billion, and annual capital expenditures are about $2 billion. Yearly operating expenses total close to $4 billion, and more than 120,000 people work for government-owned water systems.

There are two sources: groundwater and surface water. Both sources have contamination problems. Surface water includes rivers, lakes, reservoirs, and ponds. Groundwater is beneath the land surface. It is not made up of underground lakes or rivers in the usual sense. Virtually all of the rocky material below the surface of the earth is porous, and most of these pores are filled with water. One can visualize groundwater as water in a gigantic sponge. There is about fifty times more groundwater by volume than there is in the annual flow of all the rivers in the United States. Of all the fresh water in the United States, only five percent is surface water. The other 95 percent is groundwater.

Almost three-quarters of the water removed from the ground is used to sustain the economy, going for agricultural and industrial purposes. Compared with the total amount of water withdrawn, relatively little groundwater is used for drinking. Still, for half the population, groundwater is the only source of drinking water, and much of that groundwater is untreated, especially in rural areas. About 96 percent of the public water suppliers in rural areas rely on groundwater, as do 80 percent of all suppliers. About one-third of the country's major cities rely on groundwater.

There are a number of factors contributing to the growing demand for alternatives to municipally supplied water. Of these factors, not the least of which is the EPA's own "Drinking Water Infrastructure Needs Survey." In its first report to Congress, published in January 1997, EPA said, "the nation's 55,000 community water systems must make significant investments to install, upgrade, or replace infrastructure to ensure the provision of safe drinking water to their 243 million customers." Estimates are that these systems must invest a minimum of $138.4 billion over the next twenty years. Of this total, $12.1 billion is needed now to meet current Safe Drinking Water Act ("SDWA") requirements. These needs are capital costs for projects needed now to ensure compliance with existing SDWA regulations.

Treatment for microbiological contaminants under the SDWA accounts for $10.2 billion, about 84 percent of the current SDWA need. Microbiological contaminants can lead to gastrointestinal illness and, in extreme cases, death. These needs are for construction of new infrastructure at systems not now in compliance and for replacement of existing infrastructure that no longer functions adequately. In addition, almost $0.2 billion is needed to meet standards for nitrate, which causes acute health effects in children, and $1.7 billion is needed for contaminants that pose chronic health risks.

In addition to the $12.1 billion needed now to comply with the SDWA, $4.2 billion will be needed through the year 2014 for infrastructure replacement or improvement to comply with existing SDWA regulations. Another $14.0 billion will be needed for proposed regulations that will protect against microbiological contaminants and disinfection byproducts. An additional $35.7 billion is needed to replace distribution piping that poses a threat of coliform contamination. Approximately $22.3 billion of this total is needed now.

As noted above, the total infrastructure investment need is large, $138.4 billion. The largest share of this, $58.5 billion is for infrastructure improvements at large water systems. Medium and small water systems also have substantial needs totaling $41.4 billion and $37.2 billion. American Indian and Alaska Native water systems have needs totaling $1.3 billion.

Over $76.8 billion is for infrastructure improvements that are needed now to protect public health. Current needs include projects such as source, storage, treatment, and water main improvements necessary to minimize the risk of contamination of water supplies. The remaining $61.6 billion is for future needs, which are projects designed to provide safe drinking water through the year 2014. Future needs include projects to replace existing infrastructure.

According to the EPA, the estimate of total need is conservative. Many systems are unable to identify all of their needs for the 20-year period. In addition, the EPA survey examined only the needs of community water systems; non-community water systems, such as schools and churches with their own water systems, were not included. Needs associated solely with future growth were also excluded from this survey.

Treatment needs constitute the second largest category of need. The total 20-year need for treatment is $36.2 billion. All surface water and a significant percentage of ground water must be treated before it can be considered safe to drink. Over half of all treatment needs ($20.2 billion) are to reduce the threat from contaminants that can cause acute health effects.

One in every four systems needs to improve its treatment for contaminants. In addition, treatment infrastructure must be installed, upgraded, or replaced to improve treatment for contaminants that pose chronic health risks, or for contaminants that cause taste and odor or other aesthetic problems.

Service Population
Treatment	<100	101-500	501- 1,000	1,001- 3,300	3,301- 10,000	10,001- 50,000	50,001- 100,000	Over 100,001	Total
Surface Water Systems
Total Number of Systems	218	432	330	845	679	626	103	104	3,337
Pre-Disinfection, Oxidation/Softening (percent)
Chlorine	59.0	73.9	67.3	66.3	68.8	58.6	47.5	57.1	63.8
Chlorine Dioxide	0.0	0.0	0.0	5.0	4.7	13.2	14.2	7.8	6.3
Chloramines	4.6	0.0	1.1	2.1	0.0	2.2	15.5	10.8	3.1
Ozone	0.0	0.0	0.0	0.0	0.3	0.0	5.4	5.8	0.9
KmnO4	0.0	4.9	9.6	9.9	15.2	28.3	25.9	28.5	16.0
Predisinfection/ oxidation	0.0	0.0	2.0	2.9	0.6	9.2	5.1	4.3	3.5
Lime/Soda softening	6.8	9.8	20.9	16.2	14.3	11.7	3.5	5.9	12.5
Recarbonation	0.0	0.0	0.0	0.0	2.1	4.7	0.6	6.3	1.9
Post-Disinfection (percent)
Chlorine	49.7	51.6	80.6	62.8	77.9	71.1	73.8	63.6	67.5
Chlorine Dioxide	0.0	0.0	0.0	0.0	0.3	4.9	5.9	11.2	1.6
Chloramines	0.0	0.0	0.0	2.9	2.1	15.6	29.4	24.2	8.1
Postdisinfection combine	0.0	0.0	0.0	2.1	4.0	3.9	1.9	1.6	3.0
Fluoridation	0.0	4.9	13.9	32.4	42.6	48.8	49.9	63.6	35.5
Ground Water Systems
Total Number of Systems	9,042	10,367	4,443	4,422	2,035	1,094	120	56	31,579
Pre-Disinfection, Oxidation/Softening (percent)
Chlorine	64.2	69.9	56.7	73.2	60.6	57.4	36.2	38.1	63.9
Chlorine Dioxide	1.3	0.0	0.0	0.0	0.0	0.0	3.1	0.0	0.3
Chloramines	0.0	0.0	0.0	0.0	0.0	0.6	1.4	0.7	0.1
Ozone	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.6	0.0
KmnO4	0.0	0.9	2.2	0.6	5.8	3.2	7.0	0.0	0.8
Predisinfection /oxidation	0.3	0.5	0.0	0.7	1.0	2.6	0.0	0.0	0.7
Lime/Soda softening	2.9	2.9	2.2	3.6	3.5	3.8	5.0	9.1	3.2
Recarbonation	0.0	0.5	0.0	0.6	1.4	1.5	2.8	1.1	0.6
Post-Disinfection (percent)
Chlorine	23.0	23.4	32.5	28.3	42.5	41.9	54.5	65.8	31.0
Chlorine Dioxide	0.0	1.0	0.0	0.0	0.0	0.6	0.0	0.0	0.4
Chloramines	0.0	0.0	0.0	0.0	0.1	1.1	3.9	4.3	0.3
Postdisinfection combine	0.0	0.0	0.0	0.0	0.1	0.1	0.0	0.0	0.0
Fluoridation	2.4	6.3	13.2	12.4	45.3	31.2	34.3	52.5	16.0