No. 3 (1921) MANUFACTURE OF FISH OIL AND GUANO 253 



4. No such factory shall be established in any place other than 

 the foreshore near the sea beach or the margin of a backwater or 

 flowing stream which opens direct into the sea and is subject to 

 tidal action. 



Provided that factories on the margin of backwaters or streams 

 must be situated near the opening into the sea. 



5. No such factory shall be established close to public thorough- 

 fares, railway stations or other places of public resort, and every 

 such factory shall be situated as far as possible from inhabited 

 houses. 



6. If the factory building is not an open shed, it must be lighted 

 and ventilated by doors and windows to the satisfaction of the 

 President of the Taluk Board. 



7. The floor of the factory must be properly cemented to the 

 satisfaction of the President of the Taluk Board. 



8. Proper arrangements must be made, to the satisfaction of 

 the President of the Taluk Board, for the disposal of the waste 

 water "" which remains after the fresh fish have been boiled and 



* See paragraphs 9S -102 supra. The effluent water problem is important fiom a 

 sanitary and economic point of view ; if it is properly treated and utilized not only will 

 any public nuisance be minimized but neiglibouring trei; and crop growth may be greatly 

 stimulated, as shown at Tanur and elsewhere. 



In addition to the remarks on filtering effluent water in the jiaragraphs mentioned, 

 the following extract from a recent paper by Mr. J. Don before the Institute of Water 

 Engineers is suggestive, in view of the fact that sand is of course everywhere available. 

 " It is well known ", he said, "that filtration through sand not only removes suspended 

 matters and organisms but also produces a marked alteration in the amount oi dissolved 

 material "'. Moreover, " the time re([uired for the purification of polluted liquids, e.g., 

 sewage efflmtits, is extremely brief. Ordinary sewage is rendered non-putrescible in ten 

 tninntes l\ passage ihrotigli a ripe fiUer-hed one metre thick. The time is too short for 

 bacteria to bring about the change, and it must be co.icluded that tne putrescible 

 matters have been absorbed by the comiionents of ihe filter ". It is further shown that 

 valual>le results are obtained even in unripe filters which have not dtveloi)ed the slim)- 

 skin characteristic of mature filters, especially where the fillers have been roofed into 



exclude light ; " experiments indicate that a sand filter is capable 



of absorbing fairly large amounts of ammonia and dissolved organic substances, and that 

 this action takes place rapidly ". Italics are by the present writer. 



~ Further, from a paper by Sir Daniel Hall on Kesearch in Agriculture, printed in the 

 Journal of the Royal Society of Arts for April 192 1, the following important paragraph 

 is taken : — • 



"Some of the principles brought to light in the course of this investigation have 

 been applied with remarkable success to the treatment of sewage. Current processes of 

 handling sewage cannot recover its most valuable constituent, the soluble nitrogen 

 compounds, which are either fermented to destruction or escape in the effluent and cause 

 trouble in the streams. If, however, the crude sewage be passed through a filter bed 

 made up of straw, the straw will pick the soluble nitrogen compounds out of the sewage 

 in order to start the humification process. Some 60 per cent of the nitrogen is removed 



