XI. Swimming Pools & Bathing Beaches

1. XI. Swimming Pools & Bathing Beaches A. Regulations & B. Design and safety

2. Objectives: • List and describe regulations affecting water quality in pools and bathing beaches. • Discuss design and safety consider-ations for pools and bathing beaches

3. Regulation of water quality in pools, beaches: • Sanitary quality of swimming water is determined by microbial, chemical, and physical tests described in Standard Methods for the Examination of Water and Wastewater, performed by competent laboratory personnel.

4. APHA Joint Committee on Swimming Pools and Bathing Places Recommendations: • Microbial parameters (pools): • Plate count - < 200 CFU/ml. • Coliforms - < 1.0/50 ml. • Staphylococci - < 50/100 ml.

5. Joint Committee recommendations (continued): • Physicochemical parameters (pools) - • pH - 7.2 to 8.0. • Alkalinity - 50 - 150 mg/L. • Clarity - 6 inch disc readily visible. • 8” Secchi disc used for natural waters.

6. Standards for bathing beaches: • Microbiological standards - • Total coliforms - < 500/100 ml. • Fecal coliforms - < 100/100 ml. • Fecal Streptococci - < 100/100 ml. • Salmonella, enteroviruses - 0/100 ml.

7. Standards for bathing beaches (continued): • Physicochemical parameters: • pH - 6 to 9. • Color - no abnormal changes. • Mineral oils - < 0.4 mg/L. • Surfactants - < 0.4 mg/L. • Phenols - < 0.005 mg/L. • Dissolved oxygen - 8.0 to 12.0 mg/L. • Tarry residue, floating debris - absent.

8. Swimming pool design: • Types of pools - • Recirculating • water is circulated, filtered, and chlorinated. • Fill-and-draw - (no circulation). • Flow-through (500 gal/bather/day). • Partly artificial.

9. Design considerations, bathing load limits for pools: • Provide for diving, swimming, non-swimming areas in pool • Depth - varies with diving board • 8’6” deep for 2 ft diving board up to • 12’ deep for a 10 ft diving board. • 300 ft2 pool area per diving board. • 15-30 ft2 pool area per bather.

10. Safety considerations for pools: • Diving injuries (head strikes) is the primary injury in pools. • Diving boards should be eliminated in unsupervised areas. • Nonslip pool bottoms & run out areas help prevent slips due to wet surfaces. • Water slides should terminate in at least 3 feet of water

11. Safety considerations for bathing beaches: • Standards for evaluation must be interpreted based on several factors: • Sanitary survey of the area (pollution). • Microbiological, chemical, physical water quality. • Epidemiological data indicating related illness. • Economic, social, psychological impact.

12. Other associated bathing areas: • Whirlpools, spas, and hot tubs may be associated with pools. • Infections with P. aeruginosa have been associated with several hot tubs. • L. pneumophila has also been isolated from hot tubs. • 3.0 mg/L free chlorine recommended to prevent infections. • Temp. of 100-1020 F recommended.

13. Summary: • Standards and recommendations for pool quality include potential microbial, chemical, and physical contaminants affecting aesthetic and health concerns. • Pool design and maintenance can contribute to both safety and environmental health concerns.

14. Swimming Pools, Bathing Beaches Treatment, sampling, testing of water quality

15. Objectives - students should: • Distinguish among different methods used to treat water for pools and bathing beaches. • List, describe, and discuss sampling and testing techniques for pool and bathing beach water.

16. Pool water treatment: • Disinfection - Chlorine, bromine, iodine, and UV radiation. • Chlorine and bromine are the chemical treatments of choice. • UV radiation plus hydrogen peroxide is also effective for swimming pools. • 0.6 mg/L free available residual chlorine recommended.

17. Pool water treatment (continued): • Control of pH, corrosion, scale. • pH should be adjusted to above 7.4. • (Eye irritation occurs below pH 7.4). • Addition of soda ash (sodium carbonate) raises pH (lowered by chlorine). • High pH promotes scale formation and can be lowered by addition of fresh water or acids (HCl, H2SO4, sodium bisulfiate).

18. Treatment of bathing beaches: • If turnover rates are unsatisfactory for natural waters, disinfection may be necessary. • Chlorine or other disinfectant can be added in dry or liquid form. • Natural waters can also be recirculated, filtered and chlorinated similarly to human-made pools.

19. Control of bathing beaches: • Control of algae • Copper sulfate doses of 5 lb/mg every 2-4 weeks usually controls algal growth. • Control of aquatic weeds. • Lowering of water levels during winter will kill plants. • Elimination of pathogenic protozoa. • CuSO4 and elimination of plants will help.

20. Sampling of pool, bathing beach water • Water samples should be collected by plunging collection bottle downward and forward till filled. • Sampling points should be near bathing beach area or pool outlet(s). • One sample per 300 ft of beach in about 2 ft depth of water recommended. • Sodium thiosulfate is used to eliminate free chlorine in chlorinated pool samples.

21. Summary: • Treatments for disinfection of pools (and other bathing areas) include chlorinaton, bromination, iodination, and UV radiation. • Control of pH as well as algae and weeds may be necessary in some circumstances. • Periodic sampling ensures safe levels.