Swimming Pool Codes - City of Fargo

More documents

Recommendations

Info

Diatomaceous earth is the skeletal remains of a type of microscopic plant called diatoms,which flourished in lakes in early geological times. There they decomposed, leaving onlytheir white, silica-impregnated porous skeletons, which settled to the lake bottom formingdeposits of diatomaceous earth.Basically, the operation of diatomaceous earth (D.E.) filters consists of pre-coating a numberof porous filter elements with a slurry or solution of diatomaceous earth. The key to thesystem is the filter element, the most common of which is the septum; a cloth covered plasticgrid. The cloth of the septum is initially coated with diatomaceous earth by the re-circulatingthe water from the effluent of the filter to influent through a bypass line while the D.E. feederis operating. This results in the cloth surface of the filter elements becoming coated withD.E. material. It is this “cake” of diatomaceous earth, which performs the filter action,trapping dirt on the porous D.E. while allowing the water to pass through. Once the elementshave become coated, the filter can be placed into normal operation.Most filter manufacturers recommend pre-coating at a rate of 1.0 to 1.5 pounds of filter aidmaterial per 10 square feet of filter surface area. Additional amounts of the diatomaceousearth slurry are added continuously during the filtering cycle to prevent packing of thefiltered material. The amount of slurry to be added varies with water quality, type of filter,and other conditions. As the cycle continues, the filter cake gradually builds up a resistanceto the water flow and if not carefully controlled, can reduce the efficiency of the unit.Pressure diatomaceous earth filters are back-washed when the loss-of-head reaches up to 20to 25 psi. Recommended head loss pressures vary with the filter manufacturer and may beconsiderably less for some installations. Always follow the backwash procedurerecommended by the manufacturer. Backwash consists of reversing the water flow andincreasing the water velocity up to 5 to 10 gallons per minute per square foot. Strong surgesof wash water are effective for cleaning the filter elements.Vacuum type diatomaceous filters are back-washed when the pressure loss through the filterreaches a predetermined level on a vacuum gauge. Again, the manufacturer’s operationalrecommendation should be followed. Some manufacturers recommend back washing whenthe vacuum gauge reads approximately 15 inches of mercury or about 7.5 psi. In washing,the filter aid adhering to the septum is gently broken up with water from a hose, the drainvalve is opened, and the filter cake is flushed to the drain pump.Diatomite filters should be chemically cleaned when excessive head losses are noted,immediately after pre-coating. Chemical treatment should be accomplished with a closed recirculationsystem. No damage to the re-circulation system should result when the filterelements are of synthetic or metallic material.The filter elements may be cleaned while in the filter or removed and cleaned manually.Manual cleaning is generally more effective.The amount of chemicals used for cleaning the elements, without removal from the tank, willdepend upon the degree of clogging. The filter is back-washed, filled with water, isolatedfrom the pool, and re-circulated. The necessary chemicals to be used for treatment are added21
and re-circulated through the filter tank for one to two hours. The filter is then drained,flushed, pre-coated, and placed back in operation.To remove build-up of common materials, the following methods may be applied:A. Iron. Add approximately 1 lb. of crystalline oxalic acid to each 125 gal. ofwater in the filter.B. Manganese. Same as for iron, with the addition of about 1 oz. of sodiumbisulfate for each 100 gallons of the acid solution in the filter. Add thebisulfate slowly over a period of time to prevent the formation of sulfurdioxide gas.C. Oil and Grease. Add about 1 lb. of sodium hexametaphosphate (a commercialcompound is “Calgon”) per 100 gallons of water in the filter.D. Diatomite Clogging. Same as for oil and grease.E. Organic Matter. Same as for oil and grease. An alternative of 10 ppm ofchlorine solution is sometimes effective.F. Calcium and Magnesium. Add about 1 gal. of muriatic acid per 125 gallonsof water in the filter.When cleaning the elements in the filter is not effective; removal of the elements and manualcleaning may be required. Manual cleaning of common materials from the filter elementsmay be accomplished using the following solutions:A. Iron, Calcium, and Magnesium. Dilute muriatic acid.B. Manganese. Same as for iron, with the addition of a small amount of sodiumbisulfate.C. Oil, Grease, Organic Matter, and Diatomite. An 8% solution of sodiumhexametaphosphate.Use extreme caution when handling acids, as they are harmful to the eyes, skin, and clothing.Oxalic acid is poisonous when taken internally.Washing them with a detergent in an ordinary washing machine may clean the plastic fabricand drop sleeves.5.6 CARTRIDGE FILTERSCartridge type filters have several advantages over the sand and diatomaceous earth filters.Among the advantages are much lower initial cost of installation, longer filter runs, compactsize, and replaceable filter elements. In addition, no water is wasted for back washing.Operational costs for cartridge filters are higher than for any other type of filter, however, asthe filter elements have a life expectancy of them from a few months to a few year.Cartridge filters consist of filter elements made of paper, cloth or a combination of both.Individual filter elements are normally about 12 inches in length and a few inches indiameter, but contain about 4 to 6 sq. feet of filter area. Even though cartridge filters aredesigned to operate at flows of 0.375 gallons per minute or less, the large surface areacontained in one filter element enables the size of a filter unit to remain relatively compact.22
Page 1 and 2: OPERATIONALSTANDARDS FORSWIMMING PO
Page 3 and 4: 5.3 Sand filters ..................
Page 5 and 6: CHAPTER 1 - LAWS AND REGULATIONS1.1
Page 7 and 8: 2.1 BACTERIAL TESTINGCHAPTER 2 - OP
Page 9 and 10: G. Diving is not permitted except i
Page 11 and 12: Soda ash should be applied with a s
Page 13 and 14: CHAPTER 4 - DISINFECTIONSwimming po
Page 15 and 16: a substantial amount of chloramines
Page 17 and 18: D. Always pour calcium hypochlorite
Page 19 and 20: 4.9 IODINEIodine is an effective ba
Page 21 and 22: Centrifugal pumps, which are not se
Page 23: water) to the filter in an amount s
Page 27 and 28: 6.1 SWIMMING POOL START UPCHAPTER 6
Page 29 and 30: (calcium carbonate) out of the pool
Page 31 and 32: pool. Within hours, it will be back
Page 33 and 34: CHAPTER 7 - SPECIAL POOLS7.1 WADING
Page 35 and 36: Unless the water is being chlorinat
Page 37 and 38: A-2 POOL LOADINGA. Indoor Pools:(i)
Page 39 and 40: Pounds = 1% x 5 gal. x 8.34 - 0.64
Page 41 and 42: A-5 CHLORINATOR SETTINGSGas chlorin
Page 43 and 44: immediately any reagents that touch
Page 45: F. A bottle of ammonium hydroxide s

Swimming Pool Codes - City of Fargo

Create successful ePaper yourself

Delete template?

Save as template?