CONTENTS 



CHAPTER I 



PAGES 



INTRODUCTION ... ... ... ... ... ... I-2I 



CHAPTER II 



CHEMICAL ANALYSIS OF SEWAGE AND EFFLUENTS 



Methods of collecting samples — Gauging the flow — Samples should be 

 collected proportional to the flow and corresponding to one another — 

 Weirs — Floats — V notch — Meters — Hourly variation of sewage— Official 

 methods of collection and analysis — Recommendations of the British 

 Association — Determinations of total solids — Chlorine — Free and albu- 

 minoid ammonia — Oxygen consumed — Mineral constituents ... 22-42 



CHAPTER III 



CHEMICAL ANALYSIS {continued) 



Determination of nitrates — Nitrites — Organic nitrogen — Dissolved oxygen 

 — Carbonic acid — Incubator tests — Weights discharged per day — Pro- 

 posed standards for eflluents— Ratio of chlorine to total nitrogen, and of 

 oxidized to unoxidized nitrogen ... ... ... ... 43-60 



CHAPTER IV 



BACTERIA AND OTHER ORGANISMS IN SEWAGE 



Their identification and numbers and morphological characteristics — 

 Bacterial tests for the purity of effluents — Possibility of the survival of 

 pathogenic organisms ... ... ... ... ... 61-94 



CHAPTER V 



CHEMICAL CHANGES PRODUCED BY BACTERIA 



Hydrolysis and oxidation — Nature and order of the reactions — Symbiosis 

 and antagonism — Enzymes — Classes of transformations — Utilization of 

 gases produced — Sources of energy— Nitrosification, nitrification, and 

 denitrification ... ... ... ... ... ... 95-131 



CHAPTER VI 



IRRIGATION AND SEWAGE FARMS 



Broad irrigation — Soils — Application of lime or ashes — Trenching — 

 Organisms in soils — Suitable crops — Transpiration of water — Statistics 

 of sewage farms — Systems of distribution — Ridge and furrow — Catch- 

 water — Intermittent irrigation with under-drainage — Merthyr Tydvil — 

 Calculation of dilution by subsoil water — Irrigation with previous 

 treatment — Areas required — General aspect of land treatment ... 132-149 



CHAPTER VII 



SUBSIDENCE AND CHEMICAL PRECIPITATION 



Screens — Settling tanks — Roughing filters — Clarification — Lime — Aluminium 

 sulphate— Ferric sulphate— Ferrous sulphate— Alumino-ferric — Sludge : 

 its composition, volume, and disposal ... ... ... ... 150-167 



ix 



