Swimming Pool Water Treatment Research Articles

Disinfection by-products and microbial contamination in the treatment of pool water with granular activated carbon

For swimming pools, it is generally agreed that free chlorine levels have to be maintained to guarantee adequate disinfection. Recommended free chlorine levels can vary between 0.3 and 0.6 mg/L in Germany and up to 3 mg/L in other countries. Bathers introduce considerable amounts of organic matter, mainly in the form of such as urine and sweat, into the pool water. As a consequence, disinfection byproducts (DBPs) are formed. Regulations in Germany recommend levels of combined chlorine of less than 0.2 mg/L and levels of trihalomethanes (THMs) of less than 20 microg/L. Haloacetic acids (HAAs), haloacetonitriles (HANs), chloropicrin and chloral hydrate are also detected in considerable amounts. However, these compounds are not regulated yet. Swimming pool staff and swimmers, especially athletes, are primarily exposed to these byproducts by inhalation and/or dermal uptake. In Germany, new regulations for swimming pool water treatment generally require the use of activated carbon. In this project, three different types of granular activated carbon (GAC) (one standard GAC, two catalytic GACs) are compared for their long time behaviour in pool water treatment. In a pilot plant operated with real swimming pool water, production and removal of disinfection byproducts (THMs, HAAs, AOXs), of biodegradable substances (AOC), of bacteria (Pseudomonas aeruginosa, Legionella, coliforms, HPC) as well as the removal of chlorine and chloramines are monitored as function of GAC bed depth. Combined chlorine penetrates deeper in the filter bed than free chlorine does. However, both, free and combined chlorine removal efficiencies decrease over the time of filter operation. The decreases of removal efficiencies are also observed for parameters such as dissolved organic carbon, spectral absorption coefficient, adsorbable organic carbon and most of the disinfection byproducts. However, THMs, especially chloroform are produced in the filter bed. The GAC beds were contaminated microbially, especially with P. aeruginosa. The contamination was not removable by backwashing with chlorine concentrations up to 2 mg/l free chlorine.

Pathways of trihalomethane uptake in swimming pools

Chlorination of pool water leads to the formation of numerous disinfection by-products (DBPs), chloroform usually being most abundant. Bathers and pool guardians take up various amounts of DBPs by different pathways. Identification of different uptake paths is important in order to develop a technical strategy for swimming pool water treatment and to develop focussed technical solutions to minimize THM uptake. Basically, trihalomethanes (THMs) can be taken up by inhalation, by dermal absorption, or orally (swallowing of water). In our experimental study involving up to 17 participants we quantified the body burden resulting from exposure to three different concentrations of chloroform in water and air of an indoor swimming pool, during a 60 min exercising period. Chloroform concentration of the water was 20.7, 7.1, and 24.8 μg/l and was not influenced artificially. Corresponding air CHCl3 concentrations were measured at two different levels (20 cm and 150 cm) and ranged from to 85 to 235 μg/m3. To dissociate the dermal exposure route from that of inhalation, THM concentrations were measured in the blood of subjects practicing in an indoor pool with and without scuba tanks, as well as in the blood of subjects walking around the pool without swimming. Chloroform concentrations were measured in blood samples before and after each exercise period. Blood chloroform concentration of participants with scuba tanks was 0.32+/−0.26 μg/l, without scuba tanks 0.99+/−0.47 μg/l, and for persons walking around the pool 0.31+/−0.25 μg/l. Our results indicate that THMs are mainly taken up over the respiratory pathway. Only about one third of the total burden is taken up over the skin. We examined the relationship between blood concentration and environmental chloroform concentrations by using linear regression models. Blood concentrations are correlated to air chloroform concentrations; correlation to water concentrations is less obvious.

Ozone Swimming Pool Water Treatment Under Tropical Conditions

This paper presents the first year operation report of an ozone swimming pool water treatment system under the severe conditions of tropical climate. The system installed in a 70 m3 pool with upflow hydraulics, comprises sand filtration and ozone/bromide ion treatment. Cupric sulfate was chosen as algaecide and pH was kept between 7.5 and 7.8 by adding adequate amounts of HC1. When required, a slight flocculation (aluminum sulfate, 5 mg/L) was applied weekly. Water physicochemical analyses performed twice a week throughout the year, including microbiological tests, clearly demonstrated the remarkable efficiency of the treatment, fulfilling all water quality standards, even at high bather loads and during the summer months (at water temperature higher than 31[ddot]C and an intense sunlight) being economically feasible as well. This experience will allow the extension of ozone water treatment to larger swimming pools in similar circumstances.

Magnetically-Enhanced Disinfection of Swimming Pool Waters

Magnetic water treatment (MWT) is claimed to stabilize the solution pH, reduce corrosion of materials and inactivate micro-organisms. In the specific application swimming pool water treatment, MWT is additionally claimed to decrease chlorine demand. A laboratory-scale study has been carried out under rigorously controlled conditions based on a swimming pool water analogue. The efficacy of MWT on both chlorine consumption and on the inactivation of the key sewage indicator micro-organism Escherichia coli has been evaluated. In addition, the effect on the formation of the key disinfection by-products of chloramines and trichloromethane has been studied. On the basis of a factorial experimental plan, it was found that chlorine loss was significantly suppressed by MWT. The E. coli kill rate for a given disinfectant dose was increased by an average of 25% as an effect of MWT as a result of the enhanced chlorine dissolution. It was also found that MWT reduced chloroform generation to some extent. On the other hand, no statistically significant direct effects on micro-organism deactivation were recorded.

Disinfection by-product formation in swimming pool waters: a simple mass balance

Research into swimming pool water treatment has been conducted on both bench and pilot scales. Initial work made use of a recirculatory bench-scale rig containing about 45 l of water. A more recent study was based on a 2.2 m 3-capacity pilot plant, a one-seventh linear scale model of an actual operational pool, incorporating conventional unit operations for swimming pool water treatment. The study is based on the use of a body fluid analogue (BFA), comprising the key dissolved organic and inorganic components of human perspiration and urine. Initial bench-scale trials indicated the analogue to be a reasonable representation of real body fluids in terms of levels of the key disinfection by-products (DBPs) of trihalomethanes (THMs) and chloramines (CAs) generated from conventional chemical disinfection by chlorination. Trials on the pilot-scale pool, on the other hand, indicated that: measured THM levels were generally much lower than those recorded on the bench scale, attaining equilibrium values after about 3 days of operation; chlorine demand, on the other hand, was about the same; for constant rate dosing of BFA the change in DBP levels on changing key operational determinants by ±50% was shown to be significant only on increasing the BFA dose rate (33% increase in THMs) and decreasing the disinfectant dose (50% decrease in THMs), the CA levels being largely unaffected throughout; dosing of BFA at a fluctuating rate (or intermittent) over a 14-h operating cycle produces higher levels of THMs than constant rate dosing at the same overall daily rate; the equilibrium ratio of chlorine arising in dissolved chloramines to that in dissolved THMs is around 42:1; a mass balance on the steady-state system can be carried out according to an assumption of either zero breakpointing or complete breakpointing to define the limits of DBP accumulation; the zero-breakpoint mass balance accounts for 38% of the organic carbon, 61–63% of the chlorine and 84–∼100% of the ammoniacal and amino nitrogen, the exact figures being very sensitive to assumptions made regarding trichloramine formation; the complete breakpoint analysis accounts for 52% of the chlorine for 100% oxidation of the ammoniacal and amino nitrogen, the organic carbon usage being unchanged at 38%. It is surmised from the analyses undertaken that, even at the 100% efficiency limits of Henry's law governed physical desorption or total breakpoint chlorination, a net accumulation of chlorine and carbon arises. More rigorous analysis of both the pool water and the ventilated air would reveal the extent to which such an accumulation actually takes place.

Antimicrobial processes

Antimicrobial processes

First Year Operation Report of the Corona Discharge Ozone Swimming Pool Water Treatment Systems at the Peck Aquatic Facility, Milwaukee, Wisconsin

Abstract The two corona discharge ozone swimming pool water treatment systems installed in the Peck Aquatic Center in Milwaukee, WI now have been in continuous operation since September, 1987. The two pools are part of the Karl Jewish Campus Facility of the Harold and Judy Sampson Campus of the Milwaukee Jewish Community Center. The operation of these water treatment systems has shown that safe and high quality pool water is obtained reliably and economically. One pool (Main Pool) is of Olympic size, the other (Learner pool) is designed especially for use by children. Both pools utilize a full corona discharge ozone water treatment system. They were the first ozone systems in the U.S. to be built for public pools using the process of ozonation, flocculation, filtration, ozone removal and residual chlorination. An extensive testing program was initiated in cooperation with the Wisconsin Department of Health. The bacteriological water quality from these swimming pools was in compliance with Wisconsin State ...

The Hydrozon-Kompakt Process-A New Method for Treatment and Disinfection of Swimming Pool and Bathing Water

Abstract The Hydrozon (R) Kompakt process (ozonation – sand filtration – bromination) relies on bromine (hypobromous acid/hypobromite ion) as the residual disinfectant in swimming pool and bathing water. As it performs its disinfection work, bromide ion is formed. Pool exit water is ozonized, not only to oxidize bather-added contaminants, but also to oxidize bromide ion back to hypobromous acid/hypobromite ions. Consequently, bromine is recycled in the pool water. However, the original process forms brominated hydrocarbons (brominated trihalomethanes), particularly bromoform, in excess of current German drinking water standards for total THMs (25 ug/L).

Swimming Pools – Brief Outline of Water Treatment and Management

A brief history of the development of swimming pool water treatment and management has been discussed, applicable to both large and small pools. An outline of typical bathing loads and current methods of water treatment has been presented with particular emphasis being given to disinfection. Chlorine has been the traditional sole disinfectant used since the 1920's but alternatives are continually being sought. Chief amongst the alternatives to date has been ozone, used in conjunction with chlorine. Ozone acts as a powerful oxidiser and disinfectant but has little residual effect. Chlorine is therefore used to provide a residual in the pool. Current British trends in pool design and treatment have been noted.

—Review Paper—Application Of Ozone for Treatment of Swimming Pool Water in the Federal Republic of Germany

Abstract In the fields of application of ozone plants produced by the German ozone industry, the treatment of pool water is foremost. Especially the precursors of the chlorine-nitrogen compounds (combined chlorine) and the chlorine-carbon compounds (haloforms) which, for reasons of health, are reckoned among the undesirable substances in pool water, can be considerably reduced through the use of ozone during pool water treatment. The efficiency of the treatment processes depends substantially on the reaction period of the ozone with the pool water contaminants, as is shown by tests with new processes having long ozone contact periods.

Long Contact Time Ozanation For Swimming Pool Water Treatment

The elimination of contaminants in pool water through the “ozone – activated carbon process” is done stepwise. Sieving, flocculation and filtration steps are followed by ozonation. According to the German standards for the Treatment of Swimming Pool Water, the toxic ozone has to be removed from the water by filtration through an activated carbon layer before the water is brought back into the swimming pool. The treatment step is followed by chlorination for disinfection. In the ozone process described and in most of its modifications the time available for the reaction of the ozone is very short, usually 1.5 up to 3 min. First results with ozonation of model compounds, such as urea, creatinine, amino acids, etc., have shown–that the reaction rates are rather slow. Consequently, a longer reaction time leads to an improved decontamination of the swimming pool water. The efficiency of the ozonation process with longer reaction times followed by slower filtration has been proven in a research project, e.g. by experiments with the so–called “Ozone Combi BlockR – Process”. The potassium permanganate consumption and the combined chlorine as well as the formation potential of haloforms can be reduced effectively by elongated contact timeof ozone.

Chloroisocyanurates in the treatment of swimming pool water

The equilibrium constants relating to the hydrolysis of chloroisocyanurates have been measured spectrophotometrically. The results have been used to calculate the concentration of hypochlorous acid under various conditions in swimming pools treated with chloroisocyanurates and cyanuric acid. Published results concerning the bactericidal efficiency of the system have been examined in relation to its chemistry.

Sanitary Treatment of Swimming Pool Water with Calcium Hypochlorite.

It is necessary from sanitary point of view that water for swimming pool is kept free from germs, and disinfectants containing chlorine have been widly used for this purpose. Recently, a novel disinfectant composed of neutral salt of calcium hypochlorite was developed in Japan, and the large tablet being especially suitable for disinfection of swimming pool water has been marketed since last year. In order to establish a sanitary control method of swimming pool water with the product, experiments on both continuous charge method and direct throw method of the tablets were conducted at the municipal swimming pool in Takada, Niigata-prefecture, over one swimming season. It was proved that the above mentioned methods are satisfactory to the purpose.

Development and application of high-free residual chlorination in the treatment of swimming pool water.

Development and application of high-free residual chlorination in the treatment of swimming pool water.

Swimming Pool Water Treatment

A BOUT forty years ago, the only places available for swimming jt'_ were the old swimming holes in the creeks or the sand beaches along the rivers and lakes. I can remember when I was a boy that every once in a while we would hear about boys or adults who had drowned while swimming in the river. Most of the accidents were caused by divers hitting submerged stumps, rocks, etc., and by weak swimmers wading into concealed deep holes called step-offs. As a result of these accidents, artificial pools were built to remove the hazard of step-offs, hidden stumps, and undertow. These pools were called fill-and-draw pools, that is, they were filled and then drained at the end of some definite period, such as a week or a month. The water in these pools was quite turbid and concealed disabled bathers, hence there continued to be a few deaths, although not as many as before. The fill-and-draw pools, however, had one distinct disadvantage, for they became a very good channel for spreading diseases. Hundreds of persons used the same water in the pool before it was changed, and as each person went into the pool, he carried in his quota of germs and body dirt. Consequently, infections developed easily, particularly ear infections. An attempt was made to alleviate the condition by adding fresh water daily, but this was not satisfactory. Then someone suggested that the difficulties caused by the cloudy water and by the multitude of germs in the water could be corrected by means of a system which would continuously purify the water. This system consisted of a pump which drew water from one point in the pool, forced it through filters to remove the dirt, sterilized it with chlorine or other germicide, and then returned it to the pool at

The Treatment of Swimming Pool Water with Ultraviolet Rays

The Treatment of Swimming Pool Water with Ultraviolet Rays