Part 9

_First procedure._—Weigh accurately 0.5 gram of dried sludge or 5.0 grams of dried mud and put it into a 500 cc. Kjeldahl flask. Digest it with 20 cc. of sulfuric acid, or more if necessary, and 1 cc. of copper sulfate solution to assist the oxidation. Boil for several hours until the liquid becomes colorless or slightly yellow. Oxidize the residue with 0.5 gram of potassium permanganate, and follow the “Procedure for Sewage” (pp. 21–22).

_Second procedure._—The following method is convenient for routine work at sewage disposal plants. After digestion as described in the first procedure, cool, transfer to a glass-stoppered 100 cc. flask, dilute with distilled water to 100 cc., and mix well. Transfer 50 cc. with a pipette into another 100 cc. volumetric flask, and make this portion alkaline with 50 per cent sodium hydroxide, testing a drop of the liquid on a porcelain plate with phenolphthalein to insure neutralization. The formation of a floc usually indicates that neutralization is complete. Dilute the solution to 100 cc., pour it into a small glass-stoppered bottle and permit it to stand until the next day. Nesslerize an aliquot portion of the clear supernatant liquid, and calculate the percentage of nitrogen in the material.

ETHER-SOLUBLE MATTER.

Fats are usually determined only on sewage sludge, but some mud deposits contain small quantities due to the presence of trade wastes.

_Procedure._—Weigh 0.5 to 25 grams of dry material according to the quality of the sludge or mud. Add water to the weighed portion in a porcelain dish and acidify the mixture with N/50 sulfuric acid in the presence of litmus tincture or azolitmin solution as indicator. Avoid adding too much acid as an excess gives too high results on account of fatty acid residues. Evaporate the acidified mixture to dryness on the water bath, and heat it in the hot air oven at 100° C. two to three hours. Extract the dry residue with boiling ether, rubbing the sides and bottom of the dish to insure complete solution of the fat. Three extractions with ether are usually sufficient. Filter the ether solution through a 5 cm. filter paper into a small flask. Evaporate the ether slowly, dry the fatty extract for half an hour at 100° C., cool in a desiccator, and weigh. If it is desirable, particularly with certain industrial wastes, to determine the quantity of saponified fat determine the fats with and without the addition of acid. The difference between the quantities found by the two determinations is the content of saponified fat.

FERROUS SULFIDE.

The liberation of hydrogen sulfide on adding dilute hydrochloric acid to a sludge indicates the presence of ferrous sulfide. As ferrous sulfide quickly oxidizes on exposure to air a quantitative determination of this constituent must be made immediately after collection of the sample.

_Procedure._—Heat a definite portion of the sludge with hydrochloric acid in a flask. Pass the liberated gas through bromine water or hydrogen peroxide. Determine gravimetrically the sulfate in the oxidizing solution, and calculate the equivalent of ferrous sulfide by multiplying the weight of barium sulfate by 0.376.

BIOCHEMICAL OXYGEN DEMAND.

The quantity of river mud most suitable for the determination of the biochemical oxygen demand ranges within certain limits, largely according to the amount of oxidizable matter present. For examinations of river mud prepare a 1 per cent stock suspension in distilled water or tap water saturated with oxygen and free from nitrate; use in the test a dilution of this stock suspension equivalent to a concentration of 1 to 10 grams per liter of mud. For examinations of fresh sewage sludge prepare a 1 per cent stock suspension in a similar manner, but use in the test a dilution equivalent to only 0.1 to 1.0 gram per liter of wet material. For examinations of dried sludges, which have undergone more or less oxidation higher concentrations may be required.

_Procedure._—Place a measured portion of the sample, or the proper amount of the 1 per cent stock suspension of the sample, in a 300 cc. narrow-mouth glass-stoppered bottle, and dilute it to the desired concentration with water saturated with oxygen. Determine the oxygen content at 20° C. of the waters that are used for dilution. This determination must be made before the mud or sludge is added because iron sulfide in the mud or sludge rapidly consumes part of the dissolved oxygen. Incubate at 20° C. for five days.

Shortly before the determination of the oxygen remaining in solution at the end of five days rotate the bottle once or twice to mix its contents and allow sedimentation for about 30 minutes. Siphon the greater part of the liquid through a narrow-bore siphon into a 150 cc. bottle, which has been filled with carbon dioxide. Reject the first 25 cc. of the siphoned liquid and allow a little to overflow at the end of siphoning. Determine the oxygen content of the solution in the bottle in the usual way (pp. 65–68). Report the oxygen demand in percentage of the dried mud or sludge.

ANALYSIS OF CHEMICALS.

The following sections describe the accepted methods for the analysis of the chemicals commonly used in the treatment of water.

REAGENTS.

1. Distilled water. In practically all the tests of chemicals it is necessary to use exclusively distilled water that has been freshly boiled to free it from carbon dioxide and oxygen.

2. Concentrated hydrochloric acid. Sp. gr. 1.20.

3. Hydrochloric acid, N/2.

4. Hydrochloric acid, N/10.

5. Ammonium hydroxide. Redistilled; sp. gr. 0.90.

6. Dilute sulfuric acid. Dilute 1 part of concentrated sulfuric acid with 3 parts of freshly boiled distilled water.

7. Methyl orange indicator. See page 36.

8. Phenolphthalein indicator. See page 36.

9. Bromine water.

10. Stannous chloride, N/20. This should be frequently standardized by titration against a standard iron solution. One cc. of N/20 stannous chloride is equal to 0.0028 gram of iron (Fe) estimated in the ferrous state.

11. Sodium hydroxide, N/1. Free from carbonate. This should be frequently standardized by titration against a standard acid solution in presence of phenolphthalein indicator. One cc. of N/1 sodium hydroxide is equal to 0.049 gram of sulfuric acid (H_{2}SO_{4}), or to 0.03645 gram of hydrochloric acid (HCl).

12. Sodium hydroxide, N/20. Free from carbonate.

13. Standard potassium permanganate. A N/10 solution. One cc. of N/10 potassium permanganate is equal to 0.0056 gram of iron (Fe) estimated in the ferrous state.

14. Alcohol. Ethyl alcohol, 95 per cent.

15. Sugar. Solid granulated cane sugar.

SULFATE OF ALUMINIUM.

Determine and report insoluble matter, aluminium oxide (Al_{2}O_{3}), ferric oxide (Fe_{2}O_{3}), ferrous oxide (FeO), basicity ratio, and, if present, free acid as H_{2}SO_{4}. If the material is what is known as “granular” sulfate mix it well before sampling. If it is in lump form crush it to ⅛ to ¼ inch size, mix, and sample it. It is unnecessary to grind the sample to a fine powder, but it is preferable to have the particles fairly uniform in size.

INSOLUBLE MATTER.

Treat 10 grams of the sample with 100 cc. of distilled water and digest one hour at boiling temperature. Filter through a weighed Gooch crucible and wash the insoluble matter with hot water freshly boiled to free it from carbon dioxide. Dry the crucible to constant weight at 100° C., cool, and weigh. Report the percentage of insoluble matter.

OXIDES OF IRON AND ALUMINIUM.

Dilute the filtrate from the determination of insoluble matter to 500 cc. with water free from carbon dioxide and thoroughly mix the solution. Transfer 50 cc. of the solution to a 250 cc. beaker, add about 150 cc. of water and 5 cc. of concentrated hydrochloric acid, and heat to boiling. Add ammonium hydroxide in slight excess; when the solution has been almost neutralized it is convenient to add a drop of methyl orange indicator and then to add about 0.5 cc. of ammonium hydroxide after the solution is neutral to the indicator. Digest at about 100° C. for a few minutes and filter. Some analysts prefer to wash this gelatinous precipitate with hot water by decantation, and some to wash it evenly distributed over the surface of a filter paper; either method may be used. It is difficult to free it completely from impurities and it is not necessary to do so unless unusual quantities of calcium, magnesium, sodium, or potassium are present. While the precipitate is being washed do not allow it to become dry, as it then packs and can not be washed clean. After most of the water has drained drying the filter may be hastened by placing it on a sheet of blotting paper. If much iron is present completely dry the precipitate, remove it from the paper, and ignite the paper separately. Finally, blast the precipitate, with free access of air to the crucible, for five or ten minutes, cool, and weigh as oxides of iron and aluminium (Fe_{2}O_{3} + Al_{2}O_{3}).

Subtract the content of total iron, expressed as ferric oxide (Fe_{2}O_{3}), from the weight of the combined oxides and report the difference as aluminium oxide (Al_{2}O_{3}), in percentage.

TOTAL IRON.

As filter alum usually contains 0.2 to 0.3 per cent of iron use a 10 gram sample for the determination of total iron. Treat the sample with 50 cc. of freshly boiled distilled water and add 5 cc. of concentrated hydrochloric acid and 1 cc. of bromine water. Evaporate the solution to dryness, dissolve the residue in water, and wash it into a flask with sufficient water to make the volume about 50 cc. Add 50 cc. of concentrated hydrochloric acid, boil to expel oxygen, and titrate, as hot as possible, with N/20 stannous chloride.

If a 10 gram sample is used the percentage of iron (Fe) is equal to the number of cubic centimeters of stannous chloride used multiplied by 0.028, and the percentage of iron expressed as ferric oxide is equal to the number of cubic centimeters of stannous chloride used multiplied by 0.040.

FERRIC IRON.

As filter alum usually contains 0.02 to 0.04 per cent of ferric iron use a 20 gram sample. Boil 50 cc. of distilled water to expel oxygen, add 50 cc. of concentrated hydrochloric acid, and add the sample while the solution is boiling. Keep it boiling till the sample is dissolved. The flask should be kept filled with carbon dioxide during this process by dropping in occasionally small amounts of sodium carbonate. When solution of the sample is complete titrate it hot immediately with N/20 stannous chloride.

If a 20 gram sample is used the percentage of ferric oxide (Fe_{2}O_{3}) is equal to the number of cubic centimeters of stannous chloride used multiplied by 0.020.

FERROUS IRON.

The content of ferrous iron is the difference between total and ferric iron. The percentage of ferrous oxide (FeO) is, therefore, equal to 0.90 times the difference between the percentage of total iron expressed as ferric oxide and the percentage of ferric iron expressed as ferric oxide. Report the percentage of ferrous oxide (FeO).

BASICITY RATIO.

Transfer 50 cc. of the filtrate from the determination of insoluble matter to a 200 cc. casserole and dilute it to 100 cc. Boil the solution and titrate it at boiling temperature with N/1 sodium hydroxide in presence of phenolphthalein indicator. The percentage of acidity in equivalent of sulfuric acid (H_{2}SO_{4}) is equal to the number of cubic centimeters of sodium hydroxide used multiplied by 4.9. In this titration iron and aluminium are precipitated as hydroxides and any free acid is neutralized.

Calculate the percentage of sulfuric acid equivalent to the determined percentages of aluminium oxide, ferric oxide, and ferrous oxide by the following formula:

2.88 Al_{2}O_{3} + 1.83 Fe_{2}O_{3} + 1.36 FeO.

If this percentage of acid equivalent is less than that found by titration report the difference as percentage of free acid. If the percentage of acid equivalent is greater than that found by titration the difference divided by 2.88 is the percentage equivalent to the excess of aluminium oxide present. Divide this excess by the percentage of total aluminium oxide and report the quotient as the basicity ratio.

LIME.

Mix well the sample, which should contain no lumps. If foreign matter is present grind the sample to pass a 100–mesh sieve.

Place 20 grams of granulated cane sugar and 1 gram of the sample in a 250 cc. glass-stoppered bottle, tightly stopped, and mix the mass by rolling. Do not shake hard as much of the lime could thus be lost as dust. Then add 187.4 cc. of distilled water freshly boiled to expel carbon dioxide. This makes 200 cc. of sugar solution. The lime is mixed dry with the sugar and the water added later to keep the lime from lumping. After shaking the sugar solution one hour titrate 50 cc. of it with N/2 hydrochloric acid in presence of methyl orange indicator. The acid used is equivalent to the carbonate and hydroxide in 0.25 gram of the sample.

Filter the remainder of the sugar solution, discarding the first 25 cc. of filtrate. Titrate 50 cc. of the filtrate with N/2 hydrochloric acid in presence of methyl orange indicator. The acid used is equivalent to the hydroxide in 0.25 gram of the sample.

If a 1 gram sample is used the percentage of calcium oxide (CaO) is equal to 5.6 times the number of cubic centimeters of hydrochloric acid used in the second titration; and the percentage of calcium carbonate (CaCO_{3}) equivalent to the carbonate present is equal to 10 times the difference in cubic centimeters between the results of the two titrations.

SULFATE OF IRON.

INSOLUBLE MATTER.

Treat 10 grams of the sample with 100 cc. of freshly boiled distilled water cooled to 30° C. or less. When solution is complete filter through a weighed Gooch crucible, wash, dry, cool, and weigh. Report the weight of the residue, in percentage, as insoluble matter.

IRON AS FERROUS SULFATE.

Dissolve 1 gram of the sample and dilute to 200 cc. with freshly boiled distilled water cooled to 30° C. or less. Add 5 cc. of dilute sulfuric acid (1 to 3) to a 50 cc. portion of the solution and titrate with N/10 potassium permanganate. The percentage of ferrous sulfate (FeSO_{4}.7H_{2}O) is equal to 11.12 times the number of cubic centimeters of potassium permanganate used.

ACIDITY.

Shake 12.25 grams of the sample in a 150 cc. bottle with 75 cc. of 95 per cent alcohol for ten minutes. Run a blank. Filter rapidly both sample and blank and wash rapidly with alcohol sufficient to make 100 cc. of filtrate. Titrate with N/20 sodium hydroxide in presence of phenolphthalein and subtract the result of titrating the blank from that of titrating the solution of the sample. The percentage of acidity, expressed as sulfuric acid (H_{2}SO_{4}), is equal to 0.02 times the number of cubic centimeters of sodium hydroxide used.

SODA ASH.

INSOLUBLE MATTER.

Treat 5.305 grams of the sample with 200 cc. of freshly boiled and cooled distilled water. When solution is complete filter through an asbestos mat in a weighed Gooch crucible, dry, cool, and weigh. Report the weight of the residue, in percentage, as insoluble matter.

AVAILABLE ALKALI.

Dilute the filtrate from the determination of insoluble matter to 1,000 cc. and thoroughly mix. Titrate 25 cc. of this dilution with N/10 hydrochloric acid in presence of methyl orange indicator. The percentage of available alkali, expressed as sodium carbonate (Na_{2}CO_{3}), is equal to 4 times the number of cubic centimeters of hydrochloric acid used.

CHEMICAL BIBLIOGRAPHY.

The subjoined bibliography comprises the publications cited in the text of this report. The references are arranged alphabetically by authors’ names and under each author in order of dates of publication. When different pages of a single work are cited letters are used in connection with the number that refers to the work.

Bibliography 1:

ANDREWS, L. W. Sprengel’s method for colorimetric determination of nitrates: _J. Am. Chem. Soc._, Vol. 26, pp. 388–91, 1904.

Bibliography 1a:

_a._ ASSOC. OFF. AG. CHEMISTS. Determination of iodine and bromine: _J. A. O. A. C._, Vol. 1, No. 4, pt. 1, pp. 47–8, 1916.

Bibliography 1b:

_b._ BACHMANN, FRANK. A new seal for the prevention of aeration in deaerated liquids: _J. Ind. Eng. Chem._, Vol. 6, pp. 764–5, 1914.

Bibliography 2:

BARTOW, EDWARD, and RODGERS, J. S. Determination of nitrates by reduction with aluminium: _Am. J. Public Hygiene_, new ser., Vol. 5, pp. 536–44, 1909; also _Illinois Univ. Bull._, Vol. 7, No. 2 (Water Survey Ser. No. 7), pp. 14–27, 1909.

Bibliography 2a:

_a._ BLINN, WILLIAM. Determination of manganese as sulfate and by the sodium bismuthate method: _J. Am. Chem. Soc._, Vol. 34, pp. 1379–98, 1912.

Bibliography 2b:

_b._ BUSWELL, A. M. Modified apparatus for the putrescibility test: _J. Ind. Eng. Chem._, Vol. 6, p. 325, 1914.

Bibliography 3:

CALDWELL, G. C. A method in part for the sanitary examination of water and for the statement of results, offered for general adoption: _J. Anal. Chem._, Vol. 3, pp. 398–403, 1889.

Bibliography 4:

CALKINS, G. N. A study of odors observed in the drinking waters of Massachusetts: _Report Mass. State Board of Health_, pp. 355–80, 1892.

Bibliography 5:

CHAMOT, E. M., and PRATT, D. S. A study on the phenoldisulfonic acid method for the determination of nitrates in water: _J. Am. Chem. Soc._, Vol. 31, pp. 922–8, 1909; Vol. 32, pp. 630–7, 1910; and REDFIELD, H. W., Vol. 33, pp. 366–81, 381–4, 1911.

Bibliography 6:

CLARK, H. W. Experiments upon the purification of sewage and water at the Lawrence Experiment Station: _Report Mass. State Board of Health_, pp. 427–578, 1896.

Bibliography 7:

CLARK, H. W., and FORBES, F. B. Methods for the determination of lead, tin, zinc, and copper in drinking waters: _Report Mass. State Board of Health_, pp. 577–85, 1898; pp. 498–506, 1900.

Bibliography 8:

COHN, A. I. Tests and reagents, 1st ed., p. 216, John Wiley & Sons, New York, 1903.

Bibliography 9:

DIBDIN, W. J. The purification of sewage and water, 3d ed., pp. 345–51, D. Van Nostrand Co., New York, 1903.

Bibliography 10:

DOLE, R. B. The quality of the surface waters in the United States: _U. S. Geol. Survey Water-Supply Paper_ 236, pp. 15–9, 1909.

Bibliography 11:

DRAPER, H. N. Lacmoid and carminic acid as reagents for alkalies: _Chem. News_, Vol. 51, pp. 206–7, 1885.

Bibliography 13:

DROWN, T. M., and MARTIN, HENRY. Determination of organic nitrogen in natural waters by the Kjeldahl method: _Tech. Quart._, Vol. 2, No. 3; _Chem. News_, Vol. 59, pp. 272–6, 1889.

Bibliography 14:

DROWN, T. M. The chemical examination of waters and the interpretation of analyses: _Examinations by the State Board of Health of water supplies of Mass. 1887–90_, pt. 1, Examination of water supplies, pp. 519–78, 1890.

Bibliography 15:

——. Report upon the examination of the outlets of sewers and the effect of sewage disposal in Massachusetts: _Report Mass. State Board of Health_, pp. 285–452, 1902.

Bibliography 16:

——, and HAZEN, ALLEN. A report of the chemical work done at the Lawrence Experiment Station: _Examinations by the State Board of Health of water supplies of Mass. 1887–90_, pt. 2, Purification of sewage and water, pp. 707–34, 1890.

Bibliography 17:

DUPRE, Dr. Some observations on the permanganate test in water analysis: _Analyst_, Vol. 10, pp. 118–22, 1885.

Bibliography 18:

ELLMS, J. W. A study of the relative value of lacmoid, phenacetolin, and erythrosine as indicators in the determination of the alkalinity of water by Hehner’s method: _J. Am. Chem. Soc._, Vol. 21, pp. 359–69, 1899.

Bibliography 20:

——, and BENEKER, J. C. The estimation of carbonic acid in water: _J. Am. Chem. Soc._, Vol. 23, pp. 405–31, 1901.

Bibliography 21:

FARNSTEINER, BUTTENBURG, and KORN, _Leitfaden für die chemische Untersuchung von Abwasser_, Berlin, p. 20, 1902.

Bibliography 22:

FITZGERALD, and FOSS, _Report Boston Water Board_, p. 86, 1893.

Bibliography 23:

FORBES, F. B., and PRATT, G. H. The determination of carbonic acid in drinking water: _J. Am. Chem. Soc._, Vol. 25, pp. 742–56, 1903.

Bibliography 24:

FOWLER, G. J. Sewage works analyses, pp. 21–37, John Wiley & Sons, New York, 1902;

Bibliography 24a:

pp. 31–4;

Bibliography 24b:

pp. 58–60;

Bibliography 24c:

pp. 86–9;

Bibliography 24d:

pp. 89–95;

Bibliography 24e:

pp. 96–7;

Bibliography 24f:

pp. 98–100.

Bibliography 26:

FOWLER, G. J. _Univ. of Manchester Lecture_, March, 1904, Pamphlet, p. 7.

Bibliography 27:

FOX, CHARLES J. J. On the coefficients of absorption of nitrogen and oxygen in distilled water and sea water and of atmospheric carbonic acid in sea water: _Trans. Faraday Soc._, Vol. 5, pp. 68–87, 1909.

Bibliography 29:

——. The composition of sewage in relation to problems of disposal: _Tech. Quart._, Vol. 16, pp. 132–160, 1903.

Bibliography 30:

——. Experiments upon the purification of sewage and water at the Lawrence Experiment Station: _Report Mass. State Board of Health_, pp. 447–700, 1894.

Bibliography 31:

HAYWOOD, J. K., and WARNER, H. J. Arsenic in papers and fabrics: _U. S. Agri. Dept. Bur. Chem. Bull. 86_, pp. 25–7, 1904.

Bibliography 32:

GILL, A. H. On the determination of nitrates in potable water: _J. Am. Chem. Soc._, Vol. 16, pp. 122–32, 193–7, 1894.

Bibliography 33:

GOOCH, F. A. A method for the separation and estimation of boric acid: _Am. Chem. J._, Vol. 9, pp. 23–33, 1887.

Bibliography 34:

——. A method for the separation of sodium and potassium from lithium by the action of amyl alcohol on the chlorides: _Am. Chem. J._, Vol. 9, pp. 33–51, 1887; also _U. S. Geol. Survey Bull. 422_, p. 175; also _U. S. Agri. Dept. Bur. Chem._, _Bull. 152_, p. 80, 1911.

Bibliography 35:

GOTTSCHALK, V. H., and ROESLER, H. A. Action of soap on calcium and magnesium solutions: _J. Am. Chem. Soc._, Vol. 26, pp. 851–6, 1904.

Bibliography 36:

GRANDVAL, AL., and LAJOUX, H. Nouveau procédé pour la recherche et le dosage rapide de faibles quantités d’ acide nitrique dans l’air, l’eau, le sol, etc., _Comptes rend._, Vol. 101, pp. 62–5, 1885.

Bibliography 37:

HANDY, J. O. Determination of acidity or alkalinity: _Proc. Engineers Soc. West. Pa._, Vol. 19, p. 705, 1903.

Bibliography 38:

HARRINGTON, CHARLES, and RICHARDSON, M. W. A manual of practical hygiene, 5th ed., pp. 457–62, Lea & Febiger, Phila. and New York, 1914.

Bibliography 39:

HAZEN, ALLEN. On the determination of chlorine in water: _Am. Chem. J._, Vol. 11, pp. 409–14, 1889.

Bibliography 40:

——. Apparatus for the determination of ammonias in sand sewage: _Am. Chem. J._, Vol. 12, pp. 427–8, 1890.

Bibliography 42:

——. Report on the chemical precipitation of sewage: _Examinations by the State Board of Health of water supplies of Mass., 1887–90_, pt. 2, Purification of water and sewage, pp. 735–91, 1890.

Bibliography 43:

——. A new color standard for natural waters: _Am. Chem. J._, Vol. 14, pp. 300–10, 1892.

Bibliography 44:

——. Experiments on the purification of sewage at the Lawrence Experiment Station: _Report Mass. State Board of Health_, pp. 393–448, 1892.

Bibliography 45:

——, and CLARK, H. W. On the effect of temperature upon the determination of ammonia by Nesslerization: _Am. Chem. J._, Vol. 12, pp. 425–6, 1890.

Bibliography 46:

——, and ——. On the determination of nitrates in water: _Chem. News_, Vol. 64, pp. 162–4, 1891.

Bibliography 47:

HEHNER, OTTO. Estimation of hardness without soap solution: _Analyst_, Vol. 8, pp. 77–81, 1883.

Bibliography 48:

HILLEBRAND, W. F. The analysis of silicate and carbonate rocks: _U. S. Geol. Survey Bull. 422_, pp. 113–8, 127–8, 141–6, 219–20, 221, 222, and 230, 1910.

Bibliography 49:

HOLLIS, F. S. Methods for the determination of color and the relation of the color to the character of the water: _J. N. E. Water Works Assoc._, Vol. 13, pp. 94–118, 1898.

Bibliography 50: