The filtration of public water-supplies / Third edition, revised and enlarged.

by Allen Hazen

CONTENTS.

PAGE
Chapter I.	Introduction.	[1]
II.	Continuous Filters and their Construction	[5]
	Sedimentation-basins	[8]
	Size of Filter-beds	[10]
	Form of Filter-beds	[11]
	Covers for Filters	[12]
III.	Filtering-materials	[20]
	Sand	[20]
	Sands Used in European Filters	[24]
	Effect of Size of Grain Upon Efficiency of Filtration	[30]
	Effect of Grain Size Upon Frequency of Scraping	[32]
	Selection of Sand	[33]
	Thickness of the Sand Layer	[34]
	Underdraining	[35]
	Gravel Layers	[35]
	Underdrains	[39]
	Depth of Water on Filters	[45]
IV.	Rate of Filtration and Loss of Head	[47]
	Effect of Rate Upon Cost of Filtration	[48]
	Effect of Rate Upon Efficiency of Filtration	[50]
	The Loss of Head	[52]
	Regulation of the Rate and Loss of Head in the Older Filters	[52]
	Apparatus For Regulating the Rate and Loss of Head	[55]
	Apparatus For Regulating the Rate Directly	[57]
	Apparatus For Regulating the Height of Water Upon Filters	[59]
	Limit to the Loss of Head	[60]
V.	Cleaning Filters	[68]
	Frequency of Scraping	[72]
	Quantity of Sand to Be Removed	[74]
	Wasting the Effluents After Scraping	[74]
	Sand-washing	[76]
VI.	Theory and Efficiency of Filtration	[83]
	Bacterial Examination of Waters	[93]
VII.	Intermittent Filtration	[97]
	The Lawrence Filter	[100]
	Chemnitz Water-Works	[107]
	Application of Intermittent Filtration	[111]
VIII.	Turbidity and Color, and the Effect of Mud upon Sand Filters	[113]
	The Measurement of Color	[114]
	Amount of Color in American Waters	[115]
	Removal of Color	[117]
	Measurement of Turbidity	[117]
	Relation of Platinum-wire Turbidities to Suspended Matters	[122]
	Source of Turbidity	[123]
	The Amounts of Suspended Matters in Water	[129]
	Preliminary Processes to remove Mud	[133]
	Effect of Mud upon Sand Filters	[137]
	Effect of Turbidity Upon the Length of Period	[137]
	Power of Sand Filters to Produce Clear Effluents from Muddy Water	[139]
	Effect of Mud Upon Bacterial Efficiency of Filters	[141]
	Limits to the Use of Subsidence for the Preliminary Treatment of MuddyWaters	[142]
IX.	Coagulation of Waters	[144]
	Substances used for Coagulation	[145]
	Coagulants Which Have Been Used	[150]
	Amount of Coagulant required to remove Turbidity	[150]
	Amount of Coagulant required to remove Color	[153]
	Successive Applications of Coagulant	[154]
	The Amount of Coagulant which Various Waters will receive	[155]
X.	Mechanical Filters	[159]
	Providence Experiments	[159]
	Louisville_Experiments	[161]
	Lorain Tests	[161]
	Pittsburg Experiments	[162]
	Wasting Effluent After Washing Filters	[163]
	Influence of Amount of Sulphate of Alumina on Bacterial Efficiency ofMechanical Filters	[165]
	Influence of Degree of Turbidity upon Bacterial Efficiency of Mechanical Filters	[167]
	Average Results Obtained with Various Quantities of Sulphate of Alumina	[171]
	Types of Mechanical Filters	[172]
	Efficiency of Mechanical Filters	[179]
	Pressure Filters	[180]
XI.	Other Methods of Filtration	[181]
	Worms Tile System	[181]
	The Use of Asbestos	[181]
	Filters Using High Rates of Filtration Without Coagulants	[182]
	Household Filters	[183]
XII.	Removal of Iron from Ground-waters	[186]
	Amount of Iron Required to Render Water Objectionable	[186]
	Cause of Iron in Ground-waters	[187]
	Treatment of Iron-containing Waters	[189]
	Iron-removal Plants in Operation	[192]
XIII.	Treatment of Waters	[197]
	Cost of Filtration	[200]
	What Waters Require Filtration	[207]
XIV.	Water-supply and Disease—Conclusions	[210]
Appendix I.	Rules of the German Government in Regard to the Filtration ofSurface-waters Used For Public Water-supplies	[221]
II.	Extracts from “Bericht Des Medicinal-inspectorats Des HamburgischenStaates Für Das Jahr 1892”	[226]
III.	Methods of Sand-analysis	[233]
IV.	Filter Statistics	[241]
	Statistics of Operation of Sand Filters	[241]
	Partial List of Cities Using Sand Filters	[244]
	List of Cities and Towns Using Mechanical Filters	[247]
	Notes Regarding Sand Filters in the United States	[251]
	Capacity of Filters	[254]
V.	London’s Water-supply	[255]
VI.	The Berlin Water-works	[261]
VII.	Altona Water-works	[265]
VIII.	Hamburg Water-works	[269]
IX.	Notes on Some Other European Water-supplies	[272]
	The Use of Unfiltered Surface-waters.	[275]
	The Use of Ground-water.	[276]
X.	Literature of Filtration	[277]
XI.	The Albany Water-filtration Plant	[288]
	Description of Plant.	[289]
	Capacity of Plant and Means of Regulation.	[308]
	Results of Operation.	[314]
	Cost of Construction.	[314]
Index		[317]