TIÊu chuẩn xây dựng tcxd 81: 1981



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Chú thích: Nếu nước kiểm nghiệm có hàm lượng clorua cao, lấy 100ml nước thêm lượng dung dịch bạc sunfat tương đương với hàm lượng clorua đã biết (4,40g Ag2SO4 loại tinh khiết phân tích hòa tan trong 11 nước cất; 1ml dung dịch tương ứng 1mg Cl-), lọc kết tủa bạc clorua, nước lọc dùng xác định nitrat. Nếu hàm lượng sắt lớn, thêm vào nước kiểm nghiệm 8 - 10 giọt kali - natri tatrat 20%. Nếu hàm lượng ion nitrit lơn hơn 2mgl, lấy 20ml nước kiểm nghiệm thêm 0,05g amoni sunfat, cho bay hơi đến khô trên bếp cách thủy, hòa tan cặn, lọc lấy nước trong để xác định nitrat.

2.17.7 Tính kết quả

Hàm lượng ion nitrat (NO3), mg/l; tính bằng công thức:

Trong đó:

C - nồng độ ion nitrat, đọc trên đồ thị chuẩn hoặc trên thang màu tiêu chuẩn, tính bằng mg/l;

V - thể tích nước lấy kiểm nghiệm, tính bằng ml;

50 - thể tích nước kiểm nghiệm đã hiện màu, tính bằng ml,

2.18 Amoniac và amoni

2.18.1 Phạm vi áp dụng

Phương pháp áp dụng để xác định amoniac và ion amoni trong nước không chứa các amin, clo, cloamin, axeton, rượu và các chất hữu cơ tác dụng với thuốc thử Netle. Nước có độ đục, hàm lượng sắt và sunfua cao cản trở xác định amoniac và amom.

2.18.2 Bản chất của phương pháp

Amomac và ion amoni tác dụng với Kali iođua thủy ngân (thuốc thử Netle) trong môi trường kiềm tạo thành tủa màu vàng nâu.

2.18.3 Hóa chất

+ Nước cất không chứa amomac.

+ Thuốc thử netle: Hòa tan 100g.

Hg2I loại tinh khiết phân tích và 70g K.I. loại tinh khiết phân tích và trộn với dung dịch natri hydroxyt. Dung dịch natri hidroxyt pha như sau: hòa tan 160g NaOH loại tinh khiết phân tích trong 500ml nước cất. Hỗn hợp dung dịch pha nước cất cho đủ 1l. Sử dụng phần dung dịch trong, sau khi để lắng ít nhất 4 giờ.

Natri kali tatrat, dung dịch 50%: hòa tan 50g KNC4H4O6.4H2O loại tinh khiết phân tích bằng nước cất, làm loãng đến 100ml, thêm 0,2 - 0,5ml thuốc thử Netle. Dung dịch sử dụng sau khi để lắng trong.

Komplexon III, dung dịch 50%: hòa tan 10g natri hidroxyt loại tinh khiết phân tích vào 60ml nước cất, sau đó hòa tan 50g komplexon III vào dung dịch natri hidroxyt vừa pha. Thêm nước cất cho đủ 100ml.

+ Natri hidroxyt, dung dịch 15% .

+ Amoni clorua.

Dung dịch l: hòa tan 0,2965g NH4Cl loại tinh khiết phân tích bằng nước cất và pha cho đủ ll. Như vậy lml dung dịch này chứa 0,100mg NH4 Dung dịch chì pha trước khi sử dụng.

Dung dịch II: lấy 50ml dung dịch I làm loãng đến ll bằng nước cất. Như vậy 1ml dung dịch này chứa 0,005mg NH4. Dung dịch chỉ pha trước khi sử dụng.

2.18.4 Dựng đồ thị chuẩn

Lấy 0; 0,5; l,0; 2,0; 4,0; 6,0; 8,0; 10; ... 40ml dung dịch II làm loãng đến 50ml bằng nước cất và từng dung dịch lần lượt làm như đối với nước kiểm nghiệm ở phần tiến hành thí nghiệm. Dãy dung dịch nhận được có nồng độ tương ứng 0;0,05; 0,10; 0,20; 0,40; 0,60; 0,80; 1,00; ...; 4,00 mg/l NH4+ Đo cường độ màu của từng dung dịch bằng máy đo màu quang điện.

Từ mật độ quang của các dung dịch đo được dựng đồ thị chuẩn. Trên trục dọc ghi mật độ quang, trên trục ngung ghi nồng độ dung dịch tương ứng (mg/l).

2.18.5 Pha thang màu tiêu chuẩn

Lấy 0; 0,5; 1,0; 2,0; 4,0; 6,0; 8,0; 10,0; ...; 20ml dung dịch II làm loãng đến 50ml bằng nước cất trong bình trụ Netle. Từng dung dịch lần lượt làm như đối với nước kiểm nghiệm ở phần tiến hành thí nghiệm. Dãy dung dịch nhận được có nồng độ tương ứng 0; 0,05; 0,10; 0,20; 0.40; 0,60; 0,80; 1,00; ...; 2,00 mg/l NH4+.

2.18.6 Tiến hành thí nghiệm.

Lấy 50ml nước kiểm nghiệm, thêm 1 - 2 giọt dung dịch Komplexon III hoặc dung dịch natri kali tatrat và lắc đều. Nếu nước có độ cứng cao, thêm 0,5 - 1ml, dung dịch natri Kali tatrat hoặc dung dịch komplexon III. Thêm 1ml thuốc thử Netle và lắc đều. Sau 10 phút đo cường độ màu của dung dịch bằng máy đo màu quang điện, dùng kính lọc màu tím (O = 400: 425mm), cuvet dầy l - 5cm hoặc so màu bằng mắt thường với thang màu tiêu chuẩn. Sau 30 phút kể từ khi hiện màu, màu của dung dịch không được thay đổi. Khi đo cường độ màu bằng máy đo màu quang điện, nếu nồng độ ion amoni lớn hơn 6 mg/l thì phải làm loãng rồi mới đo.

2.18.7 Tính kết quả

Hàm lượng ion amoni (NH4+), mg/l; tính bằng công thức:

Trong đó:

C - nồng độ ion amoni đọc trên đồ thị chuẩn hoặc trên thang màu tiêu chuẩn, tính bằng mg/l;

V - thể tích nước kiểm nghiệm, tính bằng ml;

50 - thể tích làm loãng nước kiểm nghiệm, tính bằng ml.

2.19 Tính cặn sấy khô ở 1050C

2.19.1 Tiến hành thí nghiệm

Lấy 200ml nước kiểm nghiệm đã lọc, cho bay hơi dần trong chén sứ đã sấy ở 1050C và cân đến trọng lượng không đổi trên bếp cách thủy đến khô. Chén sứ chứa cặn khô sấy 2 giờ ở 1050C, ổn nhiệt trong bình hút ẩm và cân nhanh đến trọng lượng không đổi

2.19.2 Tính kết quả

Tính cặn sấy khô ở 1500C (mg/l) tính bằng công thức:



Trong đó:

G - khối lượng cặn khô sấy ở 1050C, tính bằng g;

V - thể tích nước kiểm nghiệm, tính bằng ml.

2.20 Hàm lượng cặn không tan sấy khô ở 1050C

2.20.1 Tiến hành thí nghiệm

Lấy 200ml nước kiểm nghiệm lọc bằng giấy lọc đã sấy ở 1050C và cân đến trọng lượng không đổi. Giấy lọc chứa cặn sấy 2 giờ ở 1050C, ổn nhiệt trong bình hút ẩm và cân đến trọng lượng không đổi.

2.20.2 Tính kết quả

Hàm lượng cặn không tan sấy khô ở 1050C (mg/l) tính bằng công thức:

Trong đó:

G - khối lượng cặn khô sấy ở 1050C, tính bằng g;

V- thể tích nước kiểm nghiệm, tính bằng ml.

2.21 Hàm lượng cặn không tan cháy ở 6000C ,

2.21.1 Tiến hành thí nghiệm

Giấy lọc chứa cặn không tan sấy khô ở 1050C (mục 2.20) bỏ vào chén sứ đã biết trọng lượng và đem nung ở 6000C trong l giờ, ổn nhiệt trong bình hút ẩm và cân đến trọng lượng không đổi.

2.21.2 Tính kết quả

Hàm lượng cặn không tan cháy ở 6000C (mg/l) tính bằng công thức:

Trong đó:

G - Hiệu khối lượng cặn không tan sấy khô ở 1050C và cặn còn lại sau khi nung ở 6000C, tính bằng g;

V - thể tích nước kiểm nghiệm, tính bằng ml.



chú thích: Các đơn vị đo lòng kí hiệu trong tiêu chuẩn này dựa theo bảng đơn vị đo lườ ng hợp pháp hiện hành.

CONSTRUCTION STANDARD

TCXD 81:1981

Water used for construction - Methods for chemical analysis

General principles

This Standard deals with the techniques for taking, preserving, transporting samples, the methods for chemical analysis of ordinary water used for constructed serving assessment of water quality before use.

This standard does not apply to household water, water for industry, domestic sewage, industrial sewage, and water used for other special purposes.

1. Water sampling, preservation and transport of water samples.

1.1. Water shall be sampled with a plastic can, bottle, or jar with a flat stopper or a rubber stopper. The glass bottle or jar used for storing the water sample must be rinsed with a bichromate (5 g of potassium bichromate mixed with 50 ml of sulfuric acid on a double boiler, then rinsed again with clean water and then distilled water. If a plastic can is used, it must be rinsed with dilute hydrochloric acid, then rinsed again with clean water and distilled water. After the sample is taken, the sample container shall be rinsed two or three times with the sampled water. The rubber stopper must be rinsed with distilled water and dipped into melted paraffin.

1.2. The bottle must be completely filled with water without any air between the water and the stopper. After the sample is taken, the bottle shall be closed and sealed with paraffin.

1.3. The minimum amount of water sample for analysis is 31.

1.4. The period of time between the sampling and the analysis must not exceed 24 hours. If the water sample is preserved with appropriate chemicals or in a freezer, this period may be 2 - 3 days.

1.5. Do not sample water that is temporarily contaminated (by lime, cement, oil, etc.) or in contact with a new construction.

1.6. The water source must be checked at least twice a year during the dry season and the rainy season.

1.7. Sampling instruments.

The shapes of the water sampling instruments vary according to the sources of water.

1.7.1. Figure 1 - Water sampling instruments including a glass bottle (a) with a minimum capacity of 31, a wooden stick (b) with a length of 2 m - 3 m, a rubber pipe (c) and a glass pipe (d). The bottle glass is immersed in the water to a wanted depth. Water in the bottle is sucked through the glass pipe (c). The bottle is then taken out and closed with the rubber stopper.

1.7.2. Veresagin’s instrument - Figure 2: A glass bottle with rubber stoppers to which two glass pipes (No. 2 and 4) are attached. A thermometer is installed at the middle of glass pipe No. 3. Glass pipe No. 4 is connected with rubber pipe No. 5. The glass bottle must be rinsed with the bichromate mixture. When sampling, rubber pipe No. 5 with a weight (No. 7) is immersed to a wanted depth. The upper end of the rubber pipe is connected to glass pipe No. 4. Clamps No. 3 and 6 are loosened. Remove air from the bottle through glass pipe No. 2 with a pump or mouth (if the depth does not exceed 0.5m) until the bottle is filled with water. Clamps No. 3 and 6 are then tightened. Remove rubber pipe No. 5 and pour water from the bottle to the container.

1.8. Water sampling method.

1.8.1. Sampling at the tap: Connect a rubber pipe to the tap. Leave water flowing for 15 minutes then put the rubber pipe in a bottle in such a way that its end touches the bottom of the bottle. Leave the water in the bottle to change its volume for several times, then close the water with a paraffin-rinsed rubber stopper.

1.8.2. Sampling at the pump: Use a funnel to take water from the spout of the pump (the tip of the funnel must touch the bottom of the bottle).

1.8.3. Sampling at a borehole or a well: Use a weighed rope or a long stick to drop the bottle. The stopper is tied to another string. When the bottle reaches the wanted depth, pull the string to remove the stopper, then pull the bottle up and put the stopper back on.

1.8.4. Taking samples from a river: If the river is small, the sample shall be taken directly with a container where the flow is fastest. Immerse the bottle to a depth of 50 cm from the surface. Keep the water from being muddy and leave the bottle to be filled with water. If the river is large, it is necessary to take samples from both banks and at the middle of the stream at various depths, whether by hand or instrumentally. Samples shall be taken at a depth of 50 cm by hand, or the average depth instrumentally.

1.8.5. Taking samples from a pond or lake if the depth of the pond or lake is depth, samples shall be taken at a depth of 1 - 1.5 m with the instruments in Figure 2 or Figure 1. Samples shall be taken near the banks and at the middle or the pond or lake. If the pond or lake is shallow, samples shall be taken at a depth of 50 cm from the surface. Do not let the water muddle when taking samples.

1.1.2. Sampling underground water: Samples shall be taken after at least 15 minutes of continuous pumping. The pumping times depends on the capacity of the well, as long as the samples are not taken from stagnant water. Do not sample underground water with a compressed-air pump.

1.9. Taking samples to analyze special criteria.

1.9.1. Corrosive carbon dioxide In order to assess the corrosiveness of water to concrete, a separate sample must be taken to analyze corrosive carbon dioxide apart from the samples for overall analysis. A bottle with a capacity of 1 liter shall be filled with water and 4: 5g of calcium carbonate. Close the bottle tightly and leave it for 5 days. Violently shake the bottle 2 - 3 times for 5 - 10 minutes each time every day. If corrosive carbon dioxide is present in the water, the amount of bicarbonate ions will increase compared to the samples of water without calcium carbonate added to.

1.9.2. Nitrite, nitrate, ammonium crystalline residues

When nitrite or nitrate residues cannot be analyzed within 24 hours as from the sampling, add 1 ml of concentrated sulfuric acid or 2 ml of chloroform to every liter of water.

1.9.3. Hydrogen sulfide and sulfides. If hydrogen sulfide and sulfides cannot be analyzed right after the samples are taken, the samples must be preserved (by adding 10 ml of cadmium acetate or zinc acetate 10% to every liter of water, etc.). However, they must be analyzed within 24 hours as from the sampling.

1.10. Transport of water samples.

Water samples may be transported with various types of vehicles. Water bottles must be protected from collision and damage. The vehicle must have a roof.

Water samples being sent to laboratories for analysis must have labels specifying:

- The name of the water source;

- The sampling time;

- The sampling position;

- The weather during the sampling;

- Temperatures of air and water;

- Analysis requirements;

- The person in charge of sampling.

2. Analysis method

2.1. General conditions

2.1.1. The criteria of a sample of water shall be analyzed in this order: gases, oxidation state, pH, nitrite, nitrate, ammonium, etc.

2.1.2. If a criterion can be analyzed either with a specialized device or by weight comparison, the former method shall apply if the device and other conditions are satisfactory. The latter method may only be used if the former method is not possible.

2.1.3. When doing analysis using precipitation method, and when the tested substances are in dissolved form, the water sample must be preliminarily filtered. The water sample must not be filtered before determination of gases.

2.1.4. The water sample shall be diluted by adding water to the mark of the volumetric flask. Only distilled water may be mixed with chemicals. If the analysis method does not mention the use of distilled water, distilled water is still the only kind of water may be used.

2.1.5. When diluting a chemical with distilled water or mixing a chemical with another chemical, there will be two numbers connected with a plus (+) in a pair of round brackets. The first number indicates the amount of the diluted chemical, while the second number indicates the amount of distilled water or the second chemical. Example: “Dilute hydrochloric acid (1 + 99)” means a unit of hydrochloric acid is diluted with 99 units of distilled water.

2.1.6. In this standard, the purity of chemicals are symbolized in Vietnamese language. The corresponding foreign symbols are provided in TCVN 1058/71 “Chemicals. Classification of purity”

2.2. pH.

2.2.1. Measuring pH by potentiometric method.

The potentiometric method ensures high accuracy and is able to measure all ranges of pH from 1 to 14. The pH shall be measured in accordance with the instructions provided by the manufacturer.

2.2.2. Measuring pH with mixed indicators.

Each indicator has a short range of 1 - 2 pH value. When using mixed indicators, the color range will be widen.

2.2.2.1. Chemicals

Methyl red 0.2 % solution. Bromothymol blue 0.1% solution.

One portion of methyl red shall be mixed with two portions of bromothymol blue. This mixture of two indicators has a color range that can indicate pH values from 4 to 8.

Disodiumhydrophosphate 0.2 M. Nitric acid 0.1 M.

The phosphate-citrate buffer solution with pH value from 3.0 to 8.0 in Table 1.



Table 1

pH

Disodiumhydrophosphate 0.2 M

Nitric acid 0.1 m

3.0

3.2


3.4

3.6


3.8

4.0


4.2

4.4


4.6

4.8


5.0

5.2


5.4

5.6


5.8

6.0


6.2

6.4


6.6

6.8


7.0

7.2


7.4

7.6


7.8

8.0


20.5

24.7


28.5

32.2


35.5

38.5


41.4

44.1


46.7

49.3


51.5

53.6


55.7

58.0


60.4

63.1


66.1

69.2


71.7

77.2


82.3

86.9


90.8

93.6


95.7

97.2


79.5

75.3


71.5

67.8


64.5

61.5


58.6

55.9


53.3

50.7


48.5

46.4


44.3

42.0


39.6

36.9


33.9

30.8


27.3

22.8


17.7

13.1


9.2

6.4


4.3

2.8


2.2.2.2. Creating a standard colors.

Add 10 ml of buffer solution to each test tube. Add 0.6 ml (5 - 7 drops) of mixed indicators to the tube, shake it to see the color.

2.2.2.3. Running the test

Pour 10 ml of water sample to the test tube; add 0.6 ml (5 - 7 drops) of mixed indicators to the tube, shake it to see the color and compare this color to the standard colors.

2.2.3. Measuring pH with paper indicator

Paper indicator provides a simple but less accurate method than a pH meter or mixed indicators.

Dip a piece of paper indicator into the water sample and until it is evenly drenched; take it out and leave it to dry; then compare the color with the color box on the paper box.

2.3. Alkalinity

2.3.1. Scope of application

This method is meant for determination of alkalinity of every kind of water.

2.3.2. Nature of the method

The substances in the water that make the water alkaline are those that react with strong acids. The alkalinity of water is proportional to the amount of hydrochloric acid used for neutralized such substances. If pH is below 4.5, alkalinity is zero. When carbonates and hydroxides dissolve in water and increase pH to over 8.3, the part of alkalinity that is in proportion to the amount of acid necessary for reducing pH to 8.3 is called free alkalinity. The alkalinity that is in proportion to the amount of acid necessary for reducing pH to 4.5 is called total alkalinity

2.3.3. Chemicals

+ Hydrochloric acid solution, 0.1 N.

+ Phenolphthalein solution, 0.5%.

+ Methyl orange solution, 0.1%.

2.3.4. Running the test

- Free alkalinity shall be determined if pH value of the water sample is above 8.3. Pour 100 ml of water sample in a 250-ml conical flask, add 2 - 3 drops or phenolphthalein and titrate with 0.1 N hydrochloric acid until no color is seen.

- Total alkalinity: Pour 100 ml of water sample in a 250-ml conical flask, add 2 - 3 drops of methyl orange and titrate with 0.1 N hydrochloric acid until the yellow turns into orange.

2.3.5. Result calculation

Free alkalinity X1 (mgdl/l) and total alkalinity X2 (mgdl/l) is calculated as follows:

Where:


V1 - Volume of 0.1 N hydrochloric acid that reacts with phenolphthalein during titration, expressed as ml;

V2 - Volume of 0.1 N hydrochloric acid that reacts with methyl orange during titration, expressed as ml;

N - Equivalent concentration of hydrochloric acid;

V - Volume of water sample, expressed as ml

2.4. Free carbon dioxide

2.4.1. Scope of application

This method is meant for determination of free carbon dioxide in every kind of water.

2.4.2. Nature of the method

This method is based on the titration of free carbon dioxide with sodium hydroxide and phenolphthalein.

2.4.3. Testing instruments

The instrument for determination of free carbon dioxide (Figure 3) is a 250 ml sphere with a two-hole rubber stopper. One hole of burette B is connected with rubber pipe C, the other hole is connected with a bent glass pipe with valve D. Valve D is closed during the titration.

2.4.4. Chemicals

+ Sodium hydroxide solution, 0.1 N.

+ Phenolphthalein, 1% alcohol solution.

2.4.5. Running the test

Pour 100 - 200 ml of water sample (the volume of water sample depends on the content of free carbon dioxide) into the titration flask; add 0.3 - 0.5 of ground potassium sodium tartrate (if the water sample contains iron and the water hardness is found significant), 0.2 ml of phenolphthalein. Shake the flask and titrate with 0.1 N sodium hydroxide until the solution turns into a stable pink. Water must be pour quickly into the titration flask and immediate close the flask to avoid losing carbon dioxide.

The test shall be run twice. The volume of water sample in the second test is equal to the volume in the first one. Add the same amount of 0.1N sodium hydroxide as in the first titration, 0.3 - 0.5 g of potassium sodium tartrate, 0.2 ml of phenolphthalein, and keep titrating with 0.1 N sodium hydroxide until the solution turns into a stable pink. Calculate the average result after two titrations:

2.4.6. Result calculation

The concentration of free carbon dioxide (mg/l) is calculated as follows:

Where:


Vt - Volume of 0.1N sodium hydroxide used during titration, expressed as ml;

N - Equivalent concentration of sodium hydroxide;

0.044 - Miliequivalent weight of CO2;

V - Volume of water sample, expressed as ml.

2.5. Corrosive carbon dioxide

2.5.1. Scope of application

This method is meant for determination of free carbon dioxide in every kind of water.

2.5.2. Nature of the method

This method is based on the reaction between carbon dioxide and calcium carbonate, which creates an amount of bicarbonate (HCO3) that is equivalent to the amount of corrosive carbon dioxide. Bicarbonate is titrated with hydrochloric acid and methyl orange indicate, then compared to the content of bicarbonate in the water sample without
additional calcium carbonate.

2.5.3. Chemicals.

+ Hydrochloric acid, 0.1 N solution.

+ Methyl orange solution, 0.1%.

2.5.4. Running the test

Pour 100 ml of water saturated with calcium carbonate (a sample taken separately to analyze corrosive carbon dioxide) into a 250-ml conical flask, add 2 - 3 drops of methyl orange and titrate with 0.1 N hydrochloric acid until yellow turns into a reddish orange.

2.5.5. Result calculation.

The concentration of free carbon dioxide (mg/l) is calculated as follows:



Where:


V - Volume of 0.1 N hydrochloric acid that is used for titration of water saturated with calcium carbonate, expressed as ml;

V1 - Volume of 0.1 N hydrochloric acid used during titration of overall alkalinity, expressed as ml;

N - Equivalent concentration of hydrochloric acid; 0.022: Miliequivalent weight of CO2;

V - Volume of water sample, expressed as ml

2.6. Hardness of carbonate.

2.6.1. Scope of application

This method is meant for determination of content of calcium bicarbonate and magnesium bicarbonate when the water does not contain any other bicarbonate and carbonate, except for bicarbonates and carbonates of alkali metals

2.6.2. Nature of the method

When titrating the total alkalinity, bicarbonate salts of calcium and magnesium, bicarbonates and carbonates of alkali metals in the reactions, the content of such bicarbonates and carbonates (which do not contributing factors to the hardness) is determined by water sample with the same volume as the water sample used for determination of total alkalinity while boiling. While boiling Ca(HCO3)2 and Mg(HCO3)2 form precipitates in the form of CaCO3 and MgCO3. Filtered water that contains carbonates alkali metals is titrated with hydrochloric acid and methyl orange indicator.

2.6.3. Chemicals

+ 0.1 N hydrochloric acid solution.

+ Methyl orange solution, 0.1%.

2.6.4. Running the test

Pour 100 ml of water sample into a 250-ml conical flask, add some “gravel” and boil until the volume is reduced to 1/3. Filter and rinse precipitated calcium carbonate and magnesium carbonate several times with distilled water (boiled and cooled) until the volume of filtered water reaches 100 ml. Add 2 - 3 drops of methyl orange into the filtered water, then titrate with 0.1 N hydrochloric acid until the yellow turns into a reddish orange.

2.6.5. Result calculation.

The carbonate hardness is expressed as Germany degree (1 Germany degree - 10 mg/l CaO) and calculated as follows:



Where:


V1 - Volume of 0.1 N hydrochloric acid used during titration of total alkalinity, expressed as ml;

V2 - Volume of hydrochloric acid used during titration of carbonates and bicarbonates of alkali metals, expressed as ml;

N - Equivalent concentration of hydrochloric acid;

0. 02804 - Miliequivalent weight of CaO;

V - Volume of water sample, expressed as ml;

Notes: Water hardness is also expressed as miliequivalent weight. Units are converted according to Table 2, where a gren is equal to 0.0647989 g and a galon is equal to 4.5459631



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