ox THE TREATMENT VXD UTILIZATION OK SEWAGE. 149 



The tliuuderstorm which occurred on the Gth July afforded further proof 

 of the connexion between the river-water and that of the effluent dram. 

 On the morning following the storm the Avater in the river had risen 7 feet 

 6 inches perpendicular, and on walking along the bank the Inspector found 

 the river-water percolating through and flooding the ground 18 inches deep. 

 The water in the effluent drain was 3 feet 6 inches deep, and was estimated 

 to be running at the rate of 3500 to 4000 gallons per minute. 



The surface of the filtering areas was prepared for cultivation in the spring 

 of 1871, and in June of that year cabbages were planted and mangolds sown ; 

 and the crops were sold in the autumn, yiekUng very good prices. As soon 

 as cleared they were replaced by others, some of which are now in the ground, 

 and some have been sold at high prices. 



The adjoining land at Troedyrhiw, belonging to the Local Board, has been 

 cultivated as a sewage-farm proper with complete success, the croj^s grown 

 being of a high class. The Eoard also intends to apply the sewage to the 

 land before i-eferred to in the valley of the Taff, but has reduced the quantity 

 previously intended to be taken by 112 acres, since the success of the downi- 

 ward-filtration system has been demonstrated. It will of course be under- 

 stood that this latter system is in this case only intended to be used in 

 conjunction with the ordinary sewage-irrigation ; and, considered as a means 

 for the disposal of the sewage, and especially of the night-sewage, there 

 can be little doubt of the success of this method. But whether it would be 

 equally favourable in other cases, when solely relied on for the disposal and 

 purification of the sewage of other towns, and under all the difterent con- 

 ditions as to soil, water, strength of sewage, &c., is a subject upon which 

 there may be considerable doubt, but which is, nevertheless, a proper one 

 for further investigation. 



The Rivers Pollution Commissioners have recently presented another Report 

 to Parliament, in which they describe the operations at Troedyrhiw ; and they 

 therein admit that the fears expressed in their first Report, that the manurial 

 properties of sewage would be entirely lost in this process, and that the 

 treatment of the sewage of a large town by it would probably result in a 

 nuisance, have not been borne out in this case. 



The Commissioners state : — •" Our analyses show that the effluent water 

 entering the Taff from the Mcrthyr intermittent fdters was of even a more 

 highly satisfactory degree of purity than the samples which we examined 

 resulting from the process carried out on a small scale in our laboratory ; but 

 a comparison of the proportions of chlorine in the sewage and effluent 

 water shows that the whole of the latter is not derived from the former. 

 AVe find, in fact, that each gallon of the sewage, on June 19, 1871, had 

 become mixed with 2-2 gallons of subsoil-water, and that on October 20, 

 1871, each gallon of sewage had become mixed with 1-9 gallon of subsoil- 

 water. This result involves the assumption that the subsoil-water contained 

 the same proportion of chlorine as that present in the water of the neigh- 

 bouring Taff, which, according to our analyses, has 1-2 part of chlorine in 

 100,000 parts." 



It will be seen that this opinion of the C!omraissioners, founded upon 

 chemical analysis, more than confirms the conclusion of this Committee, 

 based upon the results of the gaugings taken, that the effluent sewage is 

 diluted with twice its bulk of comparatively pure water. 



The Commissioners consider, nevertheless, that the net result of the action 

 of the soil of the intermittent filters upon the sewage was highly satisfactory, 



