88 EXPERIMENT STATION EECORD. 



mercury vapor quartz lamps and favors the former type. He points out in addi- 

 tion that to use successfully ultraviolet rays for sterilization, the water must 

 first be clear and free from color, and also that the degree of sterilization will 

 depend on the velocity of the water past the lamp and the depth of the layer 

 of contact. He has doubts as to the practical use of ultraviolet light for the 

 sterilization of milli. 



Sewage disposal and sludge conversion, J. D. Watson (Surveyor, ^5 (1914), 

 No. 1147, pp. 55-59; Sanit. Rec, 53 (1914), Nos. 1259, pp. 64, 65; 1260, pp. 81, 

 82; 1261, pp. 109, 110; ahs. in Wasser u. Abwasser, 8 {1914), No. 7, p. 4i7).— 

 After discussing the sanitary aspects of sewage purification and disposal, the 

 author points out the need for the conversion of fixed nitrogen in sewage sludge 

 for fertilizing purposes. He states that according to Croolies the United King- 

 dom is discharging into the sea annually fixed nitrogen to the value of about 

 $80,000,000, He was impressed with the Dublin process for utilizing the ma- 

 nurial value of sludge, which consists of two operations, as follows: (1) The 

 fermenting of the crude sludge mixed with a small percentage of yeast, and the 

 separation of as much water as possible by this means, and (2) drying the 

 resulting sludge, mixed in this case with certain compounds containing phos- 

 phates and potash to produce a balanced fertilizer. 



The present position of the sewage disposal problem, G. J. Fowler (Engi- 

 neer [London], 117 (1914), No. 3036, p. 272; Surveyor, 45 (1914), No. 1157, pp. 

 504-506; aU. in Wasser u. Abivasser, 8 (1914), No. 7, pp. 4II, ^iS).— The author 

 discusses the sanitary aspects of sewage disposal and takes up briefly the con- 

 ditions permitting the profitable use of sewage sludge as fertilizer. 



It is pointed out that Manchester, Bradford, and other towns in the British 

 Isles are now exporting dried sewage manure at a profit which indicates a 

 great demand for properly prepared sewage manure, either alone or as a basis 

 for enrichment with artificial manures. The Emscher tank, it is stated, pro- 

 duced an inoffensive residue which was useful as a light manure and could 

 easily be enriched. In the Dublin process described above the fermented sludge 

 was dried and sold at about $12 per ton. The author anticipates the time when 

 it will be possible to purify sewage completely in a tank, with the production 

 of inoffensive sludge which can be disposed of as a manure. 



Sludge disposal, J. H. Kershaw (Sanit. Rec, 53 (1914), Nos. 1265, pp. 209, 

 210; 1266, pp. 229, 230). — Methods of sludge disposal are briefly discussed. 



Among those to which particular attention is given is the utilization of sludge 

 for agricultural purposes. It is stated that sewage sludge has long been known 

 to be a useful fertilizer, but in the author's opinion its value for this purpose 

 has been overrated and it has recently come into more or less disfavor as a 

 fertilizer because it has not produced the anticipated results or has not been 

 put into good condition for such use. It is pointed out particularly that the 

 sludge is not likely to contain as much ammonia as has often been assumed. 



An analysis of a sample of air-dried sludge is reported which shows 44.6 per 

 cent of water with traces of ammonia, 23.38 of soluble matter, 19.34 of organic 

 matter, 5.1 of iron and aluminum oxids, 0.77 of phosphoric acid, 6.81 of lime, 

 magnesia, etc., and 0.4 of nitrogen. 



ImhofE sewage tank and proposed sewage farm for Torrance, Cal., R. Ben- 

 nett (Etigin. News, 70 (1913), No. 23, pp. 1132, 1133, fig. 1; ahs. in Wasser u. 

 Abwasser, 8 (1914), No. 7, pp. -^22, 4^3, fig. 1). — ^A brief description is given of 

 a sewage disposal plant, consisting of an Imhoff tank capable of serving 2,500 

 people at a daily per capita sewage flow of 75 gal., and a 40-acre sewage farm, 

 the soil of which is light sandy loam. The tank eOluent is pumped from a 

 gathering well directly to the sewage farm. 



