97 



immediately upon contact with sea water, the organic matter 

 would initially be deposited over a relatively small area. 

 Experiments have shown, however, that sludge generally does 

 not flocculate immediately, and being lighter than sea water 

 tends to rise. 



Several observations have been made dtiring a number of 

 experiments on the reactions of sludge in sea water; namely, 

 (1) sludge in the form of large **globs*' rises towards the 

 surface, but begins to disintegrate after rising only a short 

 distance, (2) after the "globs" break up into smaller par- 

 ticles there is a tendency for the smaller pieces to settle 

 very slowly towards the bottom, (3) colloidal (and perhaps 

 clay size) particles do not always flocculate, but form a 

 residual turbidity which lasts in quiet waters for periods 

 in excess of 48 hours, (4) several experiments in which 

 simulated thermoclines were used, indicated that the therrao- 

 cline may not suppress the rising organic matter below the 

 thermocline =■ apparently no matter how much temperature 

 difference exists between the boundary layerSo 



The tendency for the sludge to rise in the experiments 

 was due in part to the lighter density of the sludge, but it 

 was also probably due to gas trapped in the large "globs". 

 Once the gas was released by disintegration of the "globs", 

 more stirface area of the sludge was exposed which facilitated 

 better f locculation. The above laboratory experiments may or 

 may not simulate actual conditions in the ocean; however, the 

 experiments did show the necessity of eliminating as much 

 grease and gas from the sludge as possible. 



