BT7EAL ENGINEEEING. 591 



Report on methods of purification of sugar refinery sewage, U. Beetholet 

 {Bill, ticrv. Sante et Hyy., 1913, Sup., pp. MII+122; abs. in Wasser u. Ab- 

 wasser, 9 (1915), No. 11, pp. 389, 390). — This report describes the processes of 

 purification of sugar refinery sewage employed in Belgium, and reviews the 

 processes employed in Germany, Austria-Hungary, France, Italy, and Russia. 



The first section discusses the composition of the sugar beet. The second 

 section points out that sugar refinery sewage is highly putrefactive and a 

 nuisance, owing to its content of nitrogenous and nonnitrogenous organic mat- 

 ter, and is contaminating to the air and to rural and other water supplies. 

 Mechanical, chemical, and biological methods of purification used are described. 

 The mechanical processes consist mainly of reduction and filtration, the 

 chemical process of reduction, precipitation, and filtration, and the biological 

 process of the oxidation of organic matter in natural soil. 



Recent results of experiments on tlie purification of sewage by aeration 

 in the presence of activated sludge, at the University of Illinois, E. Baiitow 

 and F. W. MoHLMAN (Engin. and Contract., U (1915), No. 22, pp. 433, 43/f, fig. 

 1). — ^A continuation of the experiments previously noted (E. S. R., 33, p. 786) 

 on a larger scale is reported. The purpose was- to determine the amount of 

 air required, the best method for distributing the air, the time required for 

 purification, and the quantity and quality of activated sludge formed. 



It is concluded " that activated sludge may be built up by changing sewage 

 at frequent intervals without complete nitrification of each dose of fresh sewage. 

 A considerable degree of purification is also obtained from the beginning of the 

 operation, and the time for building up adequate sludge for the process is cut 

 down very decidedly." 



One sq. ft. of filtros plate for air diffusion was not sufficient for 10 sq. ft. 

 of floor area in a tank, and 3 sq. ft. of plate per 10 sq. ft. of floor area gave 

 the best results. " It is quite essential that the plates be as nearly as possible at 

 the same level. A variation of i in. in level will cause uneven air distribution. 

 The distribution seems to become more uniform the longer the plates are 

 used. . . . The gi-eatest efficiency in air consumption will be obtained when 

 enough air is used to make the sewage nonputrescible and to keep the sludge 

 activated." 



The new equipment used in the experiments is also described. 



The treatment of sewage by aeration in the presence of activated sludge, 

 E. Baktow (Metallitrg. and Cliem. Engin., 13 (1915), No. 15, pp. 901-904, figs. 

 6). — The substance of this article has been noted above. 



Sewage disposal by means of the septic tank, J. Graham (Dam. Engin., 73 

 (1915), No. 7, pp. 198-200, figs. 7). — Detailed descriptions, with illustrations, of 

 the construction of the septic tank and the tile distribution system of residen- 

 tial sewage disposal are given, including a plan and section view of a tile sys- 

 tem on a slope. 



The action of certain bacteria on the nitrogenous material of sewage, 

 E. G. BiEGE (Amer. Jour. Pub. Health, 5 (191.5), No. 10, pp. 1048-10-56) .—Btu<\ies 

 on the effect of Bacillus coli communis, B. cloacce, B. pijocganeus, B. jwoteus vul- 

 garus, B. mesentericus ruber, and B. stibtiUs under aerobic and anaerobic condi- 

 tions and in pure cultures and in symbiosis on fresh, filtered, and sterilized 

 sewage are reported, the object being apparently to throw light on the action 

 taking place in a septic tank. Particular attention was paid to the effect on 

 free ammonia, organic nitrogen, nitrites, and nitrates. 



" Bacteriologically it was shown that B. coli was completely overgrown under 

 anaerobic conditions in the 24-hour period. Under aerobic conditions it was 



