304 THIO WATKli-SUlTLY OV TOWNS IN Till': TllOl'ICS 



grounds. Samples were found to be faintly opalescent, becoming njore so on standing, 

 anil depositing a very small amount of sediment. Tbo taste was faintly chalybeate. The 

 colony couut varied between 1000 and 2000 per 1 c.c. }i. coli, as a rule of a " flaginac " 

 and oxcretal type, was present in 1 c.c. and larger quantities, the free ammonia figure, '5 

 to -6 parts per million, was excessively high, and iron and manganese were present 

 in objectionable quantities.* 1"33 parts of iron per million and 0'17 of manganese clearly 

 Danger of indicated that there would be trouble with crenothrix growth in pipes to which such water 

 was admitted, and this proved to be the case, C. poh/xpora speedily making its appearance. 



According to Hazen, -5 part of iron per 1,000,000 is about the permissible limit, while, 

 in the Rod-El-Farag well-water in Cairo, trouble had ensued with -35 part per 1,000,000 of 

 iron and -77 part manganese. 



Dr. Beam, our Chemist, and I, reported that, as a result of the examination and a study 

 of the topography of the well district, we were led to believe — 



1. That the irqn and manganese are derived from strata and will persist in the water. 



2. That we are dealing with a mixture of deep well-w-ater whose source is the Blue 

 Nile and of superficial or ground water highly charged with micro-organisms which is 

 gaining access to the wells either through defective joints in the pipes or, what is more 

 likely, through cracks and fissures in the strata or through porous beds. 



Naturally this adverse report did not please those who had forced on the water scheme 



without due precaution, deliberation and the necessary enquiries and tests. Only one well 



had been tested, and the conditions of sampling were said to be unsatisfactory. 



Pumping trials Proper pumping trials with ordinary pumping apparatus were now commenced, the 



mixed water from 5 wells vras examined with every precaution, and the results, as will 



be seen from the conclusions to our report, were much the same. We stated that — 



" 1. From a physical staudpoiut it is apparent that the water is quite unsuitable for a town supply. It is 

 not clear when freshly pumped, and becomes distinctly turbid on standing. Jloreover, as predicted, the 

 presence of iron and manganese in the water has resulted in the rapid grow-th of the crenothrix fungus and 

 the development of an odour distinctly disagreeable. The taste is also somewhat unpleasant. 



" Such a water would infallibly cause serious trouble by leading to a blocking-up of the service pipes, 

 especially those of small calibre. The greatest trouble would result when the iron-stained filaments of the 

 fungus break off and become diffused throughout the water. This renders the water quite unfit for laundry 

 use owing to the unsightly and destructive deposit of iron mould on linen and other fabrics. Moreover, it is 

 not to be expected that people would pay water rates for water of this character. 



" In this connection we may cite the so-called ' water calamity ' of Berlin, and the similar calamities 

 recorded from Rotterdam, Charlottenburg, and many other places, including, to come nearer home, the recent 

 revelations in Cairo. It is true that aeration combined with filtration will, in most cases, remedy this evil, 

 but the filtration must be efficient, as there is already a case on record of an incompletely filtered water, from 

 which the iron was not wholly removed, resulting in the growth of crenothrix. 



" 2. From a chemical standpoint the water still remains much harder than that of the Blue Nile, and a 

 soft water is always preferable for a town supply, from an economical standpoint, owing to the action of hard 

 water on boilers and soap. The presence of iron is, of course, objectionable chiefly for the reasons already 

 detailed. 



" In our former report we mentioned that the tjuantity of iron is far in excess of what is permissible 

 in a town supply. The slight reduction in total solids and carbonates indicates that the forced pumping has 

 resulted in the drawing in of a larger amount of the water to which the contamination of the deep well-water 

 is due. 



" 3. From a bacteriological standpoint the water is in much the same condition as it was at the time 

 of the former examinations, so far as the presence of li. coli, the standard bacterial indicator of impurity, goes. 



"The number of organisms present in 1 c.c. is greater than that present in the last sample t.ikcn from 

 Well No. 3, on Jan. 19, 1008. The results of the examination of this siimple have not been submitted to the 

 Board, as the analysis was still proceeding at the time of the last meeting. 218 micro-organisms were then found 

 per 1 c.c. and true ' Hagiuac ' JS. coli was present in 1 c.c. of the water. 



" Hence, there has Ijcen very little change, and what change there is has occurred in the wrong direction. 

 In a pure, deep well-water the bacterial count at blood heat should not exceed 5 to 10 micro-organisms per 1 c.c. 



" As stated, Jl. coli is taken as the standard of pollution, and the presence of B. cnUritidis sjvr^ihnf^ merely 

 serves to add <x>nfirmation to the evidence of pollution. 



• Much free ammonia unaccomixmicd by " albuminoid," however, as is well known, is frequently found iu 

 waters containing iron and is derived from the reduction of nitrates. 



