I 60
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
a n y case t h e y may be readily corrected t o meet local conditions. LIDlE XITROGEN (26 PER CEXT AMYONIA) is unquestionably the cheapest source of nitrogen (ammonia) in this country. The sales prices are dependent to an extent upon the quantities and deliveries contracted for. The freight is allowed at $3.00 per ton of Lime Nitrogen shipped in special containers, which should cover the greater portion of territory in the United States lying within a 500 mile haulage radius of Niagara. CAUSTIC LIME is to be air-slaked on spot, z per cent weight of Lime Nitrogen used assumed at $6.00 per ton delivered. SODA ASH: 3.5 per cent of weight of Lime Nitrogen at $16.00 per ton delivered. POWER: IOO h. p. continuous at IC. per h. p. hour. STEAM at 30c. per 1000 lbs., 60 per cent weight Lime Nitrogen. WATER:z U. s. gals. per lb. ammonia. As the larger part of this is used in condensers and coolers the greater proportion may be salt water. Assumed at zc. per Ioao gals. LABOR AND SUPERINTENDENCE: Assumed at 300 men-hours per day at 30c. per man-hour. REPAIRS AND RENEWALS: $1.50 per ton ammonia, a record of long time operations. INTEREST: Assumed at 6 per cent on plant cost of $IZO,OOO. DEPRECIATION: On plant cost of $IZO,OOO depreciated in IO years, say 8 per cent. OPERATING COST O F AMMONIA PLANT Capacity 30,000 Lbs. Ammonia per Day Gas Saturated with Water a t Cooling Water Temperatures PER LB. ITEM QUANTITY RATE PERDAY AMMONIA ..... $ 3.00 $180.00 Freight. . . . . . . . . . . . . . . . 7.20 6.00 Lime . . . . . . . . . . . . . . . . . . 1 . 2 0 tons 33.60 16.00 Soda.. . . . . . . . . . . . . . . . . . 2 . 1 0 tons 0.01 24.00 P o w e r . . . . . . . . . . . . . . . . . 2400 h. p. hr. 21.60 0.30 S t e a m . . . . . . . . . . . . . . . . . 7 2 M lbs. 1.20 0.02 W a t e r . . . . . . . . . . . . . . . . . 60 M gals. 90.00 0.30 Labor. . . . . . . . . . . . . . . . . . 300 men-hrs. ..... 22.50 Repairs and Renewals, . 20.00 ..... Interest. . . . . . . . . . . . . . . . .. 26,66 Depreciation. . . . . . . . . . . . .. 24.67 .. Miscellaneous. . . . . . . . . .
.
..
TOTAL CONVERSION COST (excluding NHI losses) $451.43 $0.01505 COST O F P L A N T
On account of t h e varied building conditions existing throughout t h e country i t is almost impossible t o give a detailed estimate of the cost of plant. A recent projection of such costs made b y this Company for a plant of this size, from which I have deducted t h e cost of land, foundations a n d sludge disposal, shows t h a t an ammonia plant of t h e size herein described could b e erected for about $IZO,OOO.This plant is designed t o produce as its final product a n ammonia gas cooled t o t h e temperature of t h e available water of t h e condensers, a n d , therefore, not strictly anhydrous. This figure further assumes t h a t water a n d power are furnished t h e plant, a n d no provision is made for power or pumping plants. Steel buildings with corrugated iron sides a n d roof, a n d of a type which h a r e demonstrated themselves a s fairly satisfactory for this service are included. The limitations imposed by building laws a n d choice of architecture may force one t o materially modify this estimate, as cheaper forms of construction may be used. On t h e other hand. many may prefer a more elaborate type of building t h a n provided in t h e above estimate, which would materially raise this figure.
Voi. 8,No. z
SUNMARY
The large number of installations operating with perfect success in various parts of t h e world for a number of years have demonstrated t h e commercial possibility of making ammonia from Lime Nitrogen. The plant in its present highly developed s t a t e is extremely certain in its action a n d simple t o operate. The efficiency obtained in t h e transformation of t h e nitrogen in Lime Nitrogen into ammonia gas is upwards of 98 per cent, or almost quantitative. T h e consumption of reagents is remarkably small, a n d t h e y are cheap a n d easy to obtain in almost all parts of t h e world. T h e quality of t h e ammonia produced b y this process is not surpassed b y a n y in t h e United States. It is chemically pure as produced a n d requires no further costly a n d tedious purification t o render i t available for t h e highest grade chemical products, or for t h e production of liquefied anhydrous product. The actual cost of production of this high-grade pure ammonia on a considerable scale, which enables o n e t o t a k e advantage of t h e lower prices at which Lime Nitrogen is offered, brings high-grade cyanamidammonia into t h e market almost as cheaply as t h e more impure forms already found there, a n d very much cheaper t h a n i t is possible t o obtain a n equal quality of ammonia from gas house liquor, t h e coke ovens, etc. N E W YORK CITY
MANGANESE IN GROUND WATER AND ITS REMOVAL B y S. B. APPLEBAUM Received June 10, 1915
Ground water as a source of municipal supply is constantly growing in importance. For many municipalities it is the only available source. For others, i t is often t h e best alternative when a surface supply, formerly wholesome a n d potable, becomes sewagepolluted. In this respect, well waters rarely fail t o meet t h e demands of modern sanitary science. It is only when engineering conditions of yield in d r y periods a n d chemical considerations of t h e mineral composition of such waters are taken up t h a t difficulties arise. T h e troubles resulting from t h e hardness or iron content of ground water a n d t h e most economical methods of removing these constituents are matters well understood. B u t t h e evil effects of manganese a n d t h e pressing need of i t s removal when i t is found present do not seem t o be fully appreciated b y our water works engineers. Superintendents of municipal water works rarely, if ever, have their supplies tested for manganese a n d t h e ordinary effects of t h a t element are often probably reported as iron troubles difficult t o cure. This article is a summary of t h e experience with manganese-containing waters of European cities, especially in t h e North German alluvial plains during t h e last decade. Further details a n d much valuable matter can be found in German publications b y R. Gans, H. Luhrig a n d Weiss, extracts of which have been printed in t h e Gesundheits-Ingenieur, Journal
Feb., 1916
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
fiir Gasbeleuchtung und Cherniker-Zeitung.
Wasserversorgung a n d t h e
FORMS O F OCCURREKCE O F M A N G A N E S E I N W A T E R
Manganese, like iron, is a common element i n t h e t o p layers of alluvial soils a n d i n many plant a n d animal organisms. As a rule, manganese will be found t o occur in all ground-waters containing considerable amounts of iron. B u t there are waters also which contain much manganese a n d little iron. T h e Dresden supply is a good example with from 0.6 to 1 . 0 p. p. m. of t h e former a n d only 0.1p. p. m. of t h e latter. Being elements closely akin, both are found i n water attached t o t h e same two radicles, t h e bicarbonate a n d t h e sulfate. I n t h e soil, manganese a n d iron are usually present in insoluble forms. B u t organic m a t t e r , b y evolving free carbonic acid or hydrogen sulfide, assists in transforming these salts into t h e abovementioned soluble forms. Of t h e two, t h e sulfate is t h e more troublesome, inasmuch as it is t h e more difficult t o remove. T H E SANITARY AND TECHNICAL EFFECTS OF MANGANESE I N WATER
From a sanitary point of view i t was known as early as 1891 t h a t troubles with microscopic growths were t o be a t t r i b u t e d t o manganese as well as iron. I n Germany, Proskauer examined many of t h e growths i n pipes a n d reservoirs a n d found t h e m t o contain manganese, especially t h e Crenothrix, Gallionella a n d Chlamydothrix. These organisms absorb t h e manganese into their sheaths a n d form long, fibrous, gelatinous masses, which cut down t h e effective area a n d increase t h e friction of t h e water conduits in which t h e y lodge. Occasionally these growths are loosened b y heavy currents a n d t h e water issues from t h e faucets in a most unsightly condition. It is interesting t o note t h a t manganese in surface waters is deadly t o fish life. I t seems t h a t t h e brownish cast of such waters s h u t s out sufficient sunlight t o s t u n t fish growth a n d t h e oxides of manganese gradually accumulate in a n d clog u p t h e fish gills. I n other respects, t h e occurrence of manganese is of no very great sanitary significance. T h e usual amounts present in municipal waters do not affect t a s t e or color a n d even t h e higher quantities present in old mineral whters of repute have never seemed t o affect t h e health of persons drinking t h e m . It is for technical purposes t h a t manganese in water is of serious consequence. I n laundries, bleacheries, dye-houses, paper-mills, etc., as little as 0.j p . p. m. of manganous oxide will have a decidedly injurious effect on t h e quality of t h e materials coming into contact with t h e water. I n t h e laundries, t h e wash will show distinctly yellow streaks on ironing, I n bleacheries, t h e manganese of t h e water is oxidized during t h e bleaching period a n d precipitated on t h e goods, producing a muddy white effect a n d especially brown spots where t h e water has concentrated during drying. T h e same applies t o t h e finer classes of white paper. Manganese has a n injurious effect also on t h e fermentation processes of breweries a n d t h e colorbaths of dye-houses.
161
EXPERIENCE OF CITIES
T h e wide occurrence of manganese in European waters may be seen from t h e number of old mineral waters containing it. Among others may be mentioned Baden-Baden, Bilin, Eger, Fachingen, Gieshubel, Homberg, Kreuznach, Marenbad, St. Moritz, P y r m o n t , Salzbrunn, Tarasp a n d Wildungen. T h e cities t h a t have found manganese in their supplies a n d experienced troubles therefrom are : HuTscHEIN-water has I ,2 p. p. m. of manganous oxide. HANNOVER-Water has 0.22 p. p. rn. of manganous oxide, and manganese algae growths were found in the street mains. HALLE-water contains 0.1 to 0.5 p. p. m. manganous oxide. WIEsmDEN-Water contains 0.1 t o 1 . 3 p. p. m. manganous oxide. STETTIN-water contains 5 . 2 p. p. rn. manganous oxide. BRAuNscHwEIG-Iron removal plants were found to precipitate manganese. NEusALz-Iron removal plants were found t o precipitate manganese. BERNBERG-water contains 3 to 4 p. p. m. manganese. FRANKFORT A/O-High amounts of manganese in groundwater supply caused those supplies to be abandoned for the river Oder. BREsLAu-An attempt was made to substitute a ground-water supply for that of the river Oder but a sudden temporary high increase in the manganese content prevented any further development of the project. GLOGAU-water contains 0.7 to 6.5 p. p. m. manganous oxide. T h e experiences of t h e latter t y o cities are valuable enough t o deserve special consideration: B R E S L A U is on t h e Oder river. Until 1871 t h e source of municipal water supply was t h e unfiltered river water. Increasing pollution a n d danger of contamination caused t h e installation of a filter plant in t h a t year. This was soon outgrown a n d large covered filters were added in 1893. Even this extension did not succeed in reassuring t h e public, panic-stricken a s i t was after t h e cholera epidemic in 1892. A movement in favor of ground-water was set on foot: There was no doubt of t h e existence of considerable reserves of groundwater near Breslau, b u t its quality, a s t o iron content, h a d always been suspicious. Now t h a t methods of iron removal were thoroughly understood a n d known t o be certain i n their action, a test plant of 2 5 small wells was installed. The results were fairly satisfact o r y a n d on t h e d a t a t h u s obtained wells were bored t o yield t h e total 15,000,000gallons per day. T h e layout consisted of a b o u t three hundred 6-in. wells about 60 ft. a p a r t , pumped through collecting mains t o a n iron-removal plant of tricklers a n d sand filters. The plant was p u t in operation in t h e latter p a r t of 1904a n d i t was soon found t h a t t h e maximum safe yield was only ~o,ooo,oooogallons daily. T h e iron content of t h e water also gradually rose from 6 t o 2 0 p. p. m. b u t t h e tricklers a n d filters took care of t h e increase without great difficulty. I n t h e early p a r t of 1906, during a season of drought, t h e water table was observed steadily t o fall. On March 28, 1906, immediately after a flood of t h e Oder over t h e lands sur-
162
T H E J O I I R Y A L O F I N D V S T R I A L A N D ENGI-VEERING C H E M I S T R Y
rounding t h e wells, the chemical composition of the water changed competely over night. The total solids trebled. The iron rose t o I O O p . p. m., t h e manganese t o j o p. p. m.! and t h e water was found t o be slightly acid. The tricklers a n d filters made a strenuous effort t o remove the impurities, b u t the manganese would not precipitate. After a short while the greater number of t h e wells returned t o their normal condition. But a series of wells continued t o deliver water unfit for use and had t o be abandoned I t is interesting t o note t h a t a similar flood of the Oder, in September, 1906, reproduced t h e phenomena of 11arch. Much interesting research has been devoted t o this so-called Breslau “calamity.” Geologists, chemists and engineers have published volumes of theoretical matter. But the most probable explanation, in brief, is t h e abnormally low ground-water level, there being only about 2 f t . of water in t h e wells, assisted b y the flood of t h e Oder over t h e well area. The iron and manganese were present in t h e soil in the form of sulfides, due t o t h e action of hydrogen sulfide produced by organic matter. As t h e water level fell, air entered the soil and oxidized these sulfides to sulfates. The flood carried these soluble salts down into the ground water. Since 1906 much experimental work, especially under the direction of Dr. H. Luhrig, has been carried out in Breslau t o find a practical method of manganese removal. T h e results of these experiments will be summarized later. But t h e G L O G A U is also on$he banks of the Oder. municipal nTater supply from as far back as 1 7 0 0 on, consisted of springs in t h e hills south of t h e city. With t h e growth in population, however, t h e springs became insufficient in capacity and a search for additional supply was begun. I n 1906, therefore, test-wells were sunk on Dom Island in t h e Oder and a fair yield was obtained. The iron content, however, was from ~j t o 2 0 p. p. m. and t h e manganese, as usual, was undetermined. Nevertheless. complete plans were drawn u p for a municipal ground-water plant on Dom Island. Fortunately, Dr. Luhrig, who had been consulted, made his report before these plans were executed. He cited t h e troubles a t Breslau and warned the authorities of Glogau against taking a n y hurried false steps. T h e City decided t o investigate further, especially as t o iron and manganese removal. An experimental station was built t o handle rg,ooo gallons per hour. This plant consisted of a four-storied building, the t o p story containing coke towers, the third a n aerated-water reservoir, the second, closed sand filters, and the ground floor containing closed manganese removal filter. T h e latter, about 3l/2 f t . in diameter and 6 ft. high, was designed t o pass only about 6000 gallons per hour. I t contained a bed of manganese permutit 2 ft. deep, resting on gravel with a layer of marble in t h e t o p head. The station was p u t in operation in October, 1908, a n d proved satisfactory. I n 1910 three more manganese permutit filters were added t o take care of all t h e I ~ , O O O gallons per hour.
T‘ol. 8, S o .
2
During 1914 the Permutit Company of Berlin erected a municipal plant on Dom Island of about three times the capacity of the experimental station. This plant consists of six closed steel filters, 7 ft. 4 in. in diameter by 2 0 ft. high. These tall shells contain four decks, the upper two removing t h e iron b y aeration under pressure and filtration, t h e lower two, marble and manganese permutit, removing t h e manganese. The tall filter represents a n effort towards economy and compactness. I n 1913 a manganese permutit plant was also erected in Dresden. The municipal water contains 0 . I part per million of iron and 0 . 6 t o 1 . 0 p. p. m. of manganese. The plant consists of six closed filters I O it. in diameter and about ~j ft. high, with a capacity of I O , O O O , O O O gallons per day. J I E T H O D S O F RIANGAKESE R E M O V A L
FILTRATIOX-\vhen t h e manganese is present in the form of t h e bicarbonate a n d is accompanied b y a considerable amount of iron in the water, i t can be removed b y aeration and filtration. T h e aeration may be effected in tricklers or under pressure in a closed shell, t h e filtration following through fine sand. I n most iron-removal plants of this nature an examination of the precipitate on the filters will show the presence of the manganese thus removed. I n Strettin the open iron-removal plant was observed t o reduce the manganese content of j . 2 p. p. m. t o 0 . 2 7 p. p. m. A similar effect was noted in Wiesbaden. The shortcomings of this method of manganese removal, however, are: I-It will not remove a n y appreciable amount of manganese when the raw water contains very little iron. 2-It fails completely when t h e manganese is present as the sulfate, as a t Glogau and Breslau. 3-Even under the most favorable conditions, the manganese is not entirely removed. 4-It usually involves double pumping of the water or pumping of air. 11. ADDITIOS O F LIx-This method was one on which Dr. Luhrig in his Breslau experimental work laid great stress. He removed t h e greater part of the iron b y aeration and filtration and then added a slight excess of lime-water (2-4 per cent). The precipitates of iron and manganese t h u s formed were allowed t o settle in basins and the settled water filtered through sand. The method is a n old one and is thoroughly practical, b u t its disadvantages are: I-The addition of l i m e w a t e r requires t h e most careful chemical attendance t o control t h e amounts needed as t h e composition of t h e raw water varies. 2-An excess of lime-water is needed t o complete t h e reaction and this excess imparts a highly disagreeable taste t o t h e water. I n Breslau, the excess was successfully removed, either b y the further addition of alum, of free carbonic acid, or by mixing t h e effluent with filtered river water. Either of t h e latter operations adds t o t h e complexity of the method. I. AERATIOK A K D
Feb., 1916
T H E J O C R N A L O F 1 - V D C S T R I A L A N D E N G I N E E RI N G C H E M I S T R Y
111. A D D I T I O K OF PERMANGAKATE-This Was also one of t h e Breslau experiments. Permanganate is an oxidizing agent par excellence, and attacks t h e manganese in all forms. Like lime it is a reagent of old standing. With an average of 8 p. p. m . of >Ins04 in water, it will not involve a cost of t r e a t m e n t greater t h a n 0 . 6 of a cent per 1000 gallons, b u t its disadvantages are similar t o a n d greater t h a n those of t h e lime method. I-With manganese in t h e sulfate from one of t h e products of t h e oxidation is sulfuric acid. This has t o be completely neutralized, preferably by filtration through marl, which increases t h e hardness of t h e water. 2-The chemical control a n d t h e attendance necessary is still more troublesome t h a n with lime-water. A slight excess of permanganate is undesirable a n d a n under-dose leaves manganese in t h e effluent. I V . O Z O K E OR ELECTROLYSIS-Dr. Luhrig also experimented in t h e laboratory with ozone a n d electrolysis. Ozone is still more effective t h a n permanganate as a n oxidizing agent, b u t t h e precipitates formed are extremely fine, making it necessary t o r u n t h e filters at slow velocities. Furthermore, t h e cost of t r e a t m e n t for plants on a large scale is still prohibitive, which is also t h e case with electrolysis.
V. F I L T R A T I O K
THROCGH
MAKGAXESE
PERMCTIT-
This method is t h e one t h a t was successfully tried out in Glogau in 1908 a n d later made t h e basis of t h e municipal plant there installed. Permutit is a n artificial zeolite or complex alumina silicate, first made on a laboratory scale in Germany b y R. Gans in connection with soil studies. Much research h a d been devoted t o fertilizers a n d t h e manner in which t h e nutritive elements reached t h e plant roots. It was noted t h a t t h e operation proceeded more rapidly a n d effectively in some soils t h a n in others. Gans’ theory was, in brief, t h a t this transmission of potassium a n d ammonium involved a chemical reaction or exchange between t h e soil a n d t h e fertilizer which only t h e zeolite soils could accomplish. He prepared a n artificial zeolite by fusing together quartz, aluminum silicate a n d alkali-carbonate at a temperature approximating t h a t of t h e earth’s natural furnace, t o demonstrate this reaction. By t h u s omitting t h e inactive impurities a product was obtained many times more effective t h a n t h e natural zeolite in exchanging t h e bases found in soil for those of t h e fertilizer. This power of exchange was found t o be great enough t o make permutit commercially applicable for water purification. Undesirable bases i n water, like iron, manganese, calcium a n d magnesium can be easily exchanged for sodium b y passing t h e water through a bed of permutit a t rates greater t h a n those of t h e usual rapid sand practice. For manganese removal, t h e method t h a t was successfully applied a t Glogau a n d later at Dresden is a slight modification of t h e direct exchange reaction. T h e sodium permutit obtained from t h e usual melt i n t h e furnace is treated with a dilute solution of manganous chloride t o form manganese permutit b y exchange. The latter is t h e n oxidized b y a 2 t o 3 per
163
cent solution of permanganate. This treatment is carried out in t h e closed shell a n d t h e product t h u s formed is used directly as a filter bed for manganese removal. The reactions t h a t t a k e place may be written as follows: T h e most probable chemical formula for sodium permutit is 2% 02. A1103. S a 1 0 ; let us denote this b y Na2O.Pmt. Then N a O . P m t MnClz = h l n O . P m t 2NaCl illInO.Pmt zNaMnO4 = NazO.Pmt MnO.hIn2O;. The higher oxides t h a t are formed in t h e second reaction are finely divided a n d coat t h e porous grains of sodium permutit. They possess t h e intense oxidizing power which seems necessary for t h e complete precipitation of manganese, t h e permutit acting as a catalytic agent or a carrier of t h e active material. The following chemical reaction t h e n takes place : NazO.Pmt Mn0.Mn20i. 21LIn(HC03)2 = SasO.Pmt 5Mn02 4C02 2H20 The filter bed becomes inactive when there are no higher oxides left on t h e permutit grains. When this happens permanganate is once again added a n d t h e bed is regenerated. The Glogau experimental filter above described passed 678,000 gallons between J a n . 15th, 1909,a n d Feb. 2nd, 1909,at a rate of 9 . 2 gallons per sq. ft. per minute with only one regeneration. About 8 . 8 lbs. of permanganate were used, giving 7 7 , 2 0 0 gallons per lb. of permanganate. Besides regeneration, t h e only other attention given t o t h e filter is a daily stirring u p of t h e bed b y means of a rake a n d a backwash. The water t h u s wasted averages about I per cent of t h e total amount filtered. Assuming t h e cost of permanganate (potash preferably) t o be IOC. per lb., t h e cost of chemical for treatment b y manganese permutit ranges from 0 . I t o 0 . 2 cent per 1000 gallons, depending upon t h e amount of manganese in t h e water. T h e cost of installation is not excessive on account of t h e high rates of filtration used. The rate a t Glogau is about 71/2 gallons per sq. ft. per minute. I n Dresden t h e rate is 2 0 gallons per sq. ft. per minute. The advantages of this method of manganese removal over those previously described may be summarized thus: I-The compactness, due t o high rates of filtration, saves floor space. 2-The pressure t y p e of installation avoids a n y extra pumping. 3-The absence of a n y continuous chemical feed reduces t h e necessary attendance t o t h a t of a rapid sand plant. 4-The effluent has no corrosive tendencies on pipe. (Aeration is frequently followed b y pitting due t o dissolved oxygen in t h e water.) 5-The manganese, in whatever form it may be present, is completely removed.
+
+
+
259
EAST1
8 2 STREET, ~ ~
NEWYORKCITY
+
+ +
+
+
+
