No. 3 (1921) MANUFACTURE OF FISH OIL AND GUANO 20/ 



may have been found necessary for sanitary reasons. Here in 

 India, even with a powerful sun as an accessory, it would be 

 impossible; very expensive plant is needed, fuel is dear, the 

 factories are minute, and the fluid rapidly putrefactive even though 

 disinfectants are used. 



99. The proper use of the effluent water appears to be in 

 irrigating fruit trees (coconuts, etc.) or field crops; it is economic- 

 ally wrong — unless sanitarily necessary — to pour useful manurial 

 water into the sea, and sanitarily wrong to let it stagnate in the 

 sand. In one factory the water was taken by a coconut owner 

 who considered it profitable to send large boats for the fluid, 

 while it is certain that coconuts bordering the Tanur yard 

 developed abnormally by its aid. But the matter has never been 

 studied, although comparative experiments were started at Tanur. 

 In the small quantities applied to each tree no nuisance is percep- 

 tible if the sand 'round the trees is properly handled; moreover 

 since it is an objection that surface watering is inimical to the 

 trees as tending to mere surface growth of roots, it is quite possible 

 to remove both this objection and any sanitary objection by 

 inserting a couple of 2" drain pipes, of ordinary porous material, 

 vertically in the soil three feet or so from the tree and on opposite 

 sides of it, so that the water passes at once below the surface and 

 the sun's action, and penetrates deeply into the sub-soil; this is 

 also economical of water in ordinary tree irrigation. In this way 

 a potential nuisance can be avoided and turned into an economic 

 benefit. 



100. It is suggested that the following procedure may be 

 adopted where it is sought to utilize the effluent water or where, if 

 it cannot be sent into the sea, it might otherwise be a nuisance. 

 Receive all such water in a masonry tank of which there should be 

 two, each sufficient for the receipt of the whole effiuent water from 

 a day's working, so that while one is under treatment as below the 

 other may receive the current day's outflow. Treat the fluid with 

 a sufficiency of lime in powder, taking care to sprinkle the powder 

 in successive portions on to the surface ; this will temporarily 

 deodorize the fluid and at the same time precipitate solid impuri- 

 ties as a sludge or sediment ; the supernatant fluid can then be 

 baled or carried to any available coconuts as at Tanur yard. 

 The calcareous sludge at the bottom of the tank can then be 

 removed and dried with very little annoyance. 



