Swimming Pool Water Treatment Research Articles

Enhancement of swimming pool water quality by nanotechnology

Because of the hazards associated with the use of chlorine in pool water treatment, a commercial polysulfone ultrafiltration membrane was utilized. These membranes were coated with varying concentrations of Ag-ZnO nanomaterial (0.05, 0.1, 0.2) and employed in a filter system designed to imitate the swimming pool water treatment process. The experiment lasted three months (April, May, and June) and was carried out for three days each month. The impact of nano-Ag-Zno on the UF nanocomposite membrane was investigated. To analyze the mechanical properties of the membranes, scanning electron microscopy (SEM), porosity, and contact angle were used. The findings reveal that treating the substrates with Ag-ZnO enhanced their hydrophilicity and porosity. Acommercial polysulfone membranes were coated with amixture of Ag-ZnO nanoparticles using the spray pyrolysis technique. The impact of nano-Ag-ZnO on the UF nanocomposite membrane was investigated. To analyze the mechanical properties of the membranes, SEM and contact angle were used. According to the findings, applying Ag-Zno in different concentration to the substrates boosted their hydrophilicity and porosity and aconcentration (2%) could achieve the goal of the research, which is to reduce the use of chlorine disinfection by eliminating Escherichia Coli bacteria, which considered acommon species in swimming pool water.

A New Method Based on a Zero Gap Electrolysis Cell for Producing Bleach: Concept Validation.

Commercial bleach (3.6 wt% active chlorine) is prepared by diluting highly concentrated industrial solutions of sodium hypochlorite (about 13 wt% active chlorine) obtained mainly by bubbling chlorine gas into dilute caustic soda. The chlorine and soda used are often obtained by electrolyzing a sodium chloride solution in two-compartment cells (chlorine-soda processes). On a smaller scale, small units used for swimming pool water treatment, for example, allow the production of low-concentration bleach (0.3 to 1 wt% active chlorine) by use of a direct electrolysis of sodium chloride brine. The oxidation and degradation reaction of hypochlorite ion (ClO−) at the anode is the major limiting element of this two-compartment process. In this study, we have developed a new process to obtain higher levels of active chlorine up to 3.6%, or 12° chlorometric degree. For this purpose, we tested a device consisting of a zero-gap electrolysis cell, with three compartments separated by a pair of membranes that can be porous or ion-exchange. The idea is to generate in the anode compartment hypochlorous acid (HClO) at high levels by continuously adjusting its pH to a value between 4.5 and 5.5. In the cathodic compartment, caustic soda is obtained, while the central compartment is supplied with brine. The hypochlorous acid solution is then neutralized with a concentrated solution of NaOH to obtain bleach. In this work, we studied several membrane couples that allowed us to optimize the operating conditions and to obtain bleach with contents close to 1.8 wt% of active chlorine. The results obtained according to the properties of the membranes, their durability, and the imposed electrochemical conditions were discussed.

Identification of Potential Harmful Transformation Products of Selected Micropollutants in Outdoor and Indoor Swimming Pool Water.

This paper presents the estimation of micropollutant decomposition effectiveness and the identification of transformation intermediates formed during selected processes used in the treatment of swimming pool water. Tests were carried out under both indoor and outdoor conditions to simulate the removal of contaminants in different types of pool water basins. Model swimming pool water spiked with caffeine, carbamazepine, bisphenol A and oxadiazon were subjected to chlorination, ozonation, UV radiation, and artificial and sun lightening, carried out as single or combined processes. It was noted that organic micropollutants decompose faster during exposure to natural sunlight than artificial lighting. Caffeine and carbamazepine belong to compounds that are resistant to single ozone or light decomposition. Bisphenol A was completely removed by the action of the chlorination agent NaOCl. The highest compound removal degrees were noted for the integrated action of natural sunlight, NaOCl and O3. This process allows also for the decomposition of all caffeine and oxadiazon decomposition by-products that potentially are toxic to swimming pool users.

Long-Term Monitoring of Water and Air Quality at an Indoor Pool Facility during Modifications of Water Treatment

Previous research has shown that volatile disinfection byproducts (DBPs) can adversely affect the human respiratory system. As a result, swimming pool water treatment processes can play important roles in governing water and air quality. Thus, it was hypothesized that water and air quality in a swimming pool facility can be improved by renewing or enhancing one or more components of water treatment. This study is designed to identify and quantify changes in water and air quality that are associated with changes in water treatment at an indoor chlorinated swimming pool facility. Reductions in aqueous trichloramine (NCl3) concentration were observed following the use of secondary oxidizer with its activator. This inclusion also resulted in significant decreases in the concentrations of cyanogen chloride (CNCl) in pool water. The concentration of urea, a compound that is common in swimming pools and that functions as an important precursor to NCl3 formation, as well as a marker compound for the introduction of contaminants by swimmers, was also reduced after the addition of the activator. Concentrations of gas-phase NCl3 did not decrease after the treatment processes were changed. The collection of long-term water and air quality measurements also allowed for an assessment of the effects of bather load on water and air quality. In general, the concentrations of urea (an NCl3 precursor), liquid-phase NCl3, and gas-phase NCl3 all increased during periods of high swimmer number.

The metabolic diversity of soil microbial community in the petroleum exploitation area of Northern Shaanxi, China

Aiming at the problem that most of the water treatment technology of swimming pools cannot effectively remove harmful substances, the design of a method for water treatment technology of indoor swimming pool based on ozone disinfection was proposed. Firstly, the organic composition of swimming pool water is analyzed, and the related evaluation indexes of swimming pool water are selected. Then, according to the disinfection performance of ozone disinfection, the appropriate ozone disinfection method is selected. Finally, according to the characteristics of the ozone disinfection method, the design of the water treatment cycle filtration system is completed to achieve the treatment of swimming pool water. The experimental results show that the method is superior to the conventional method by keeping urea at about 1.3 mg/L, the highest COD removal rate approaching 100%, and the lowest value only 59%. Moreover, the effect of particle reduction is obvious after the application, and the daily ozone consumption is always lower than 0.9, which fully verifies the feasibility and economic value of the method.

Impact of Low-Pressure UV Lamp on Swimming Pool Water Quality and Operating Costs

UV lamps are being increasingly used in the treatment of swimming pool water, mainly due to their abilities to disinfect and effectively remove chloramines (combined chlorine). However, the application of UV lamps in a closed loop system, such as that in which swimming pool water is treated, creates conditions under which chlorinated water is then also irradiated with UV. Thus, the advanced oxidation process occurs, which affects the transformation of organic matter and its increased reactivity, and hence the higher usage of chlorine disinfectant. In addition, UV lamps require electrical power and the periodic replacement of filaments. In order to assess whether the application of a low-pressure UV lamp is justified, water quality tests and an analysis of the operating costs (including the energy consumption) of the water treatment system were carried out for two operation variants—those of the low-pressure UV lamp being turned on and off. The experiments were carried out on the real object of the AGH University of Science and Technology sports swimming pool for one year. The consumption of electricity and water treatment reagents was also measured. The following values of the selected parameters of the swimming pool water quality were observed (for without and with UV lamp, respectively): 0.68 and 0.52 mg/L combined chlorine; 3.12 and 3.02 mg/L dissolved organic carbon; 15.70 and 15.26 µg/L trihalomethanes; 7 and 6 cfu/mL mesophilic bacteria; and 6 and 20 cfu/mL psychrophilic bacteria. Generally, the statistically important differences in water quality parameters were not observed, thus the application of the low-pressure UV lamp in the swimming pool water treatment technology did not bring the expected improvement in water quality. However, the higher consumption of electric energy (by 29%) and chlorine disinfectant (by 15%), and the need to periodically replace the lamp filaments significantly increased the operating costs of the water treatment system (by 21%) and its ecological impact, thus this technology cannot be considered as profitable or ecological.

Effect of a Commercial Disinfectant CLORICAN® on Acanthamoeba spp. and Naegleria fowleri Viability

Swimming pool water treatment by chemicals is an essential step to avoid microbial proliferation and infections namely caused by free living amoeba such as, for example, primary amebic meningoencephalitis and Acanthamoeba keratitis. In the present study, a commercial reactive, CLORICAN, based on chlorine dioxide, was evaluated against Acanthamoeba spp. and Naegleria fowleri. We observed that CLORICAN could eliminate in a short period of incubation time both amoebae. Furthermore, Naegleria fowleri’s trophozoites were more sensitive than those of Acanthamoeba spp. By means of inverted microscopy, the chlorine dioxide was found to greatly affect morphology shape by increasing the cell size shrinkage.

Impact of swimming pool water treatment system factors on the content of selected disinfection by-products

Recommendations regarding disinfection by-products (DBPs) in pool waters consider the content of trihalomethanes (THMs) and combined chlorine (CC) as indicators of DBPs based on which the health risk for swimmers and staff of pool facility can be determined. However, the content of DBPs in swimming pools depends on many factors. In this paper, the influence of selected factors (physicochemical parameters of water and technological parameters) on the content of THMs and CC in pool water was determined. During the 6-month period, 9 pools of various functions were analyzed. The water in pools was subjected to the same method of treatment. The content of THMs and CC was compared against the content of organic matter, free chlorine and nitrates, pH, temperature, redox potential and turbidity, technological, and operational parameters. The THM content did not exceed the limit value of 0.1 mg/L. The content of CC varied significantly, from 0.05 to 1.13 mg Cl2/L. It was found that a very large water volume per person, in comparison to a very small one, contributed to the low content of CC and THMs. The high load expressed as m3 of water per person or m2 of water per person and the specific function of hot tubs (HT1 and HT2) led to the average concentration of CC in these pools exceeding 0.3 mg Cl2/L. The THM concentrations in hot tubs (especially in HT1) were also among the largest (0.038–0.058 mg/L). In terms of the analyzed microbiological indicators, the quality of the tested pool water samples was not in doubt. It was found that the purpose of the pool, its volume, and number of swimmers should be the key parameters that determine the choice of methods of water treatment. The research on the pool water quality in the actual working conditions of swimming pool facilities is necessary due to the need to preserve the health safety of swimmers and staff.

An Evaluation of the Effectiveness of Nanosilver in Swimming Pool Water Treatment - Water Quality and Toxicity of the Product

Abstract The possibility of applying a colloidal solution of nanosilver in the closed circuit of pool water treatment as a complementary disinfectant with chlorine compounds was presented. The applied nanosilver solution is characterized, by hygienic certificate, as having a very high biocidal effect. Samples of pool water for the control were taken from 5 points of a pool circuit. The safety of the water was appraised by comparing the bacteriological and physicochemical test results with the admissible values specified by hygienic requirements. The results show that nanosilver solution can be successfully applied for precoating the filter bed and supporting the disinfection system. Special attention was paid to the bacteriological purity and stability of the disinfectant concentration. The influence of concentration of colloidal nanosilver (0-25 mg/dm3) on bacterial bioluminescence, crustacean mortality and macroscopic effect of root growth and seed germination of selected plants was analysed. The results obtained were related to the current knowledge on the impact of nanoparticles on indicator organisms. It was found that due to many still unknown mechanisms of interaction and transformation of nanoparticles in living organisms, further study of this issue is necessary.

Analysis of Free and Combined Chlorine Concentrations in Swimming Pool Water and an Attempt to Determine a Reliable Water Sampling Point

The analysis of free chlorine concentrations in swimming pool water makes it possible to assess the antiseptic effect of the disinfectant. The concentration of combined chlorine determines the comfort of swimming and indicates if there is a threat from DBP (disinfection by-products). The distribution of free and combined chlorine concentration was analyzed in four basins differing in seasonality of use and in the applied water flow systems. After considering the distribution of free and combined chlorine content in characteristic points of pools, an attempt was made to determine the most reliable point for assessing the quality of water and its suitability for swimming. Such searches should aim to identify the places with the worst water quality. The most uniform distribution of the concentrations of both free and combined chlorine was observed at the middle point of swimming pools, while at points near the corners and walls of swimming pools a varied distribution was observed. Such a control strategy, based on the least favorable test results at a point considered as characteristic, would make it possible to verify the parameters of the swimming pool water treatment system and thus minimize the risk to swimmers’ health.

Application of pre-ozonation process in swimming pool water treatment technology

Application of pre-ozonation process in swimming pool water treatment technology

Microfluidic Device for the Determination of Water Chlorination Levels Combining a Fluorescent meso-Enamine Boron Dipyrromethene Probe and a Microhydrocyclone for Gas Bubble Separation.

Chlorination procedures are commonly applied in swimming pool water and wastewater treatment, yet also in food, pharmaceutical, and paper production. The amount of chlorine in water needs to be strictly controlled to ensure efficient killing of pathogens but avoid the induction of negative health effects. Miniaturized microfluidic fluorescence sensors are an appealing approach here when aiming at online or at-site measurements. Two meso-enamine-substituted boron dipyrromethene (BODIPY) dyes were found to exhibit favorable indication properties, their reaction with hypochlorite leading to strong fluorescence enhancement. Real-time assays became possible after integration of these fluorescent probes with designed two-dimensional (2D) and three-dimensional (3D) microfluidic chips, incorporating a passive sinusoidal mixer and a microhydrocyclone, respectively. A comparison of the two microfluidic systems, including their abilities to prevent accumulation or circulation of microbubbles produced by the chemical indication reaction, showed excellent fluidic behavior for the microhydrocyclone-based device. After coupling to a miniaturized optical reader for fluorescence detection, the 2D microfluidic system showed a promising detection range of 0.04-0.5 mg L-1 while still being prone to bubble-induced fluctuations and suffering from considerably low signal gain. The microhydrocyclone-based system was distinctly more robust against gas bubbles, showed a higher signal gain, and allowed us to halve the limit of detection to 0.02 mg L-1. The use of the 3D system to quantify the chlorine content of swimming pool water samples for sensitive and quantitative chlorine monitoring was demonstrated.

The Influence of the Filtration Bed type in the Pool Water Treatment System on Washings Quality

Abstract This paper presents the influence of the type of filtration beds, used in swimming pool water treatment systems, on the quality and the possibility of reuse of washings. The research covered 4 pool cycles with sand, sand and anthracite, glass and diatomaceous beds. The degree of contamination of washings was assessed on the basis of physical, chemical and bacteriological tests. The possibility of washings drainage into the natural environment was considered, and the results of the research were compared with the permissible values of pollution indicators for wastewater discharged to water or ground. A direct management of washings from the analysed filters proved impossible mainly due to the high content of TSS (total suspended solids) and free chlorine. Washings were subjected to sedimentation and then the supernatant was stirred intensively. As a result of these processes, the quality of washings was significantly improved. This allowed planning to supplement the pool water installations with systems for washings management.

Efficient treatment of swimming pool water by photoelectrocatalytic ozonation: Inactivation of Candida parapsilosis and mineralization of Benzophenone-3 and urea

Swimming pool water (SPW) poses a potential risk to both human health and the environment due to the presence of contaminants of emerging concern (including components of sunscreens), pathogenic microorganisms, and eventually products of the reaction of chlorine with urea, such as chloramines, which are found in the water. The present work describes the efficient combination of photoelectrocatalysis and ozonation (PEC + O3) to treat both simulated and real contaminated pool water. An annular bubble reactor was designed based on a cylindrical TiO2 nanotubes electrode irradiated by an UVB 36 W lamp with an injection of ozone/air. Benzophenone-3 (BP-3) was used as a model of harmful commercial sunscreen to test the reactor efficiency. The results showed that O3-based treatment efficiently oxidized BP-3 (100% in 20 min) but reached only 32% of mineralization after 120 min of treatment, whereas O3 + PEC-based treatment reached 82% of TOC removal (with 100% BP-3 removal in 20 min). The addition of 106 CFU mL−1 of Candida parapsilosis did not interfere in BP-3 mineralization, and the fungus was found to be completely inactivated after 45 min of treatment. Furthermore, the presence of urea (10 and 20 mg L−1) was not found to exert any significant influence over BP-3 degradation. The method was successfully applied in real SPW sample fortified with 10.0 mg L−1 of Benzophenone-3. The findings show that O3 + PEC-based treatment could be a good alternative for SPW treatment, once it leads to efficient disinfection and mineralization of harmful organic compounds.

Application of Ultrafiltration in a Swimming Pool Water Treatment System.

Swimming pool water was treated using an ultrafiltration process using ceramic and polymer membranes for comparison. It was determined that the efficiency of the process depended on the type of membrane used. The polymer membrane decreased the absorbance and concentration of combined chlorine in the pool water to a greater extent than the ceramic membrane. In the case of a ceramic membrane, the concentration of combined chlorine in the permeate exceeded the limit values. During the ultrafiltration process, the permeate flux decreased, causing the blockage of membrane pores. The extent of this phenomenon was similar for both tested membranes. In the case of the ceramic membrane, flushing it with water could significantly restore its initial performance. For both tested membranes, a high regeneration efficiency was observed during chemical treatment with an alkaline solution. SEM photos of the polymer membrane showed low resistance of this polymer to the chlorine present in the swimming pool water.

Ecotoxicity of Biocides (Chemical Disinfectants) - Lethal and Sublethal Effects on Non-target Organisms

The aim of this paper was to assess de ecotoxicity effects of four biocides, used as chemical disinfectants for swimming pool water treatment, on non-target organisms such as Daphnia magna and Heterocypris incongruens crustaceans. The tests showed a significant difference of sensitivity between species. The biocides, at the recommended disinfection doses, induced a very toxic or toxic effect on Daphnia magna, based on their mortality percentage. On the contrary, the observed ostracods lethal effects were generally less than 50% mortality and no significant growth inhibitions were observed. Overall, the ostracods had a higher tolerance to subacute doses, including disinfection doses of 20 mg/L (potassium mono persulfate), 5 mg/L (sodium dichloroisocyanurate), 8 mg/L (trichloroisocyanuric acid 90%) and 7 mg/L (trichloroisocyanuric acid 87-88%). In the context of a continuous biocides market expansion, the paper highlighted that our research proposed testing methods to obtain fast and accurate ecotoxicity data for a sustainable biocide production / authorization and also for an environmental hazard assessment.

Application of UVOX Redox® for swimming pool water treatment: Microbial inactivation, disinfection byproduct formation and micropollutant removal

Alternative disinfection technologies may overcome some of the limitations of conventional treatment applied in swimming pools: chlorine-resistant pathogens (e.g. Cryptosporidium oocysts and Giardia cysts) and the formation of chlorinated disinfection byproducts. In this paper, results of full scale validation of an alternative disinfection technology UVOX Redox® (hereinafter referred to as UVOX) that combines ozonation and UV irradiation are presented. The performance was assessed in terms of microbial inactivation, disinfection byproduct formation and micropollutant removal. UVOX was able to achieve 1.4–2.7 log inactivation of Bacillus subtilis spores at water flows between 20 and 76 m³/h. Lower formation of trichloromethane and dichloroacetic acid was observed with UVOX followed by chlorination when compared to chlorination alone. However, due to the use of ozone and the presence of bromide in the pool water, the formation of trihalomethanes and haloacetic acids shifted to more brominated byproducts. Chlorine alone was able to remove the target micropollutants: acetaminophen, atenolol, caffeine, carbamazepine, estrone, estradiol, and venlafaxine (>97% removal) after 24 h, with the exception of ibuprofen (60% removal). The application of UVOX in chlorinated water enhanced the removal of ibuprofen. The application of UVOX could lower the usage of chlorine to the level that provides an adequate residual disinfection effect.

N2 yields from monochloramine conversion by granular activated carbons are decisive for effective swimming pool water treatment

Inorganic chloramines (mono-, di- and trichloramine) are formed in swimming pool water from the unintended reaction of free chlorine with ammonia that is introduced by bathers. Monochloramine is of particular interest as it is known to react further in pool water forming harmful DBPs, such carcinogenic N-nitrosodimethylamine (NDMA). During pool water treatment with granular activated carbon (GAC) filters, monochloramine is transformed by chemical reactions on the carbon surface to N2 and ammonia. As ammonia is led back into the pool where it is chlorinated again under the renewed formation of inorganic chloramines, it is recommended to use GACs with a high N2 yield for monochloramine transformation in pool water treatment.In this study, yields of N2 and ammonia from monochloramine conversion by commercially available GACs were determined using a fixed-bed reactor system under conditions that are typical for swimming pool water treatment. The N2 yields remained constant with on-going exposure of the GAC to monochloramine and ranged from 0.5% to 21.3%, depending on the type of GAC used. Correlation analyses were conducted to identify carbon properties that can determine the N2 yield for monochloramine conversion, such as the amount of oxygen groups, the elemental composition and the trace metal content. It was found that the N2 yield significantly correlates with the copper content of the tested carbons. Model calculations combining pool hydraulics with formation/abatement of inorganic chloramines and NDMA as well as chloramine transformations in GAC filters showed that the concentration of inorganic chloramines and carcinogenic NDMA can be decreased by a factor of ∼2, if the tested GACs could be modified to convert up to ∼50% of the monochloramine to N2.

Degradation of UV-filter Benzophenon-3 in aqueous solution using TiO2 coated on quartz tubes.

BackgroundBenzophenone-3 (BP-3), one of the emerging pollutants, is commercially synthesized as UV filter used in cosmetics and other personal care products and its occurrence in the aquatic environment has widely been reported. The goal of this study was to enhance an AOP method for degradation of UV filter Benzophenone-3 in aqueous solutions.MethodIn this study, sol-gel method was applied to synthesis TiO2 nanoparticles. Subsequently, the nanoparticles were successfully coated on quartz tubes. The synthesized catalyst was characterized using XRD, FE-SEM and EDX analysis. Then, the efficiency of photocatalytic process using TiO2 coated quartz tubes for BP-3 degradation from synthetic and real aqueous solution was assessed.ResultThe optimum contact time and solution pH for the highest BP-3 degradation in the synthetic solution were found at 15 min and 10, respectively. The maximum degradation (98%) of BP-3 by photocatalytic process was observed at 1 mg/L initial BP-3 concentration using 225 cm2 of catalyst surface area. Among the three applied kinetic models, the experimental data were found to follow the first-order equation more closely with the rate constant of 0.2, 0.048 and 0.035 1/min for 1, 3 and 5 mg/L of initial BP-3 concentration, respectively. In order to investigate the potential of this process for real effluent, the treatment of swimming pool water and wastewater treatment plant was examined and BP-3 degradation close to 88% and 32.1 was achieved, respectively.ConclusionBased on the obtained data, the photocatalytic process could successfully be applied for water treatment in swimming pools and other effluent containing BP-3 with low turbidity. The advantage of this study is that the synthesized catalyst can be used repeatedly needless to remove catalyst from the treated solution. In addition, AOPs can effectively eliminate organic compounds in aqueous phase, rather than transferring pollutants into another phase. The limitation of this study is that in solution with high turbidity photocatalytic degradation can be hampered and pre- treatment is needed to reduce turbidity.

Ocena wpływu systemu cyrkulacji na poziom stężeń mikrozanieczyszczeń w układzie oczyszczania wody basenowej

Ocena wpływu systemu cyrkulacji na poziom stężeń mikrozanieczyszczeń w układzie oczyszczania wody basenowej