U.S. ARMY SERVICE FORGES OFFICE OF CHIEF OF ENGINEERS ENGINEERING MANUALt chapter 7 ARMY SERVICE FORCES OFFICE OF THE CHIEF OF ENGINEERS WASHINGTON ENGINEERING MANUAL CHAPTER VH DESIGN OF SANITARY SEWERS, SEWAGE PUMPING STATIONS AND SEWAGE TREATMENT PLANTS E. M. CHAPTER VII JANUARY 1943 DESIGN OF SANITARY SEWERS, SEWAGE PUMPING STATIONS AND SEWAGE TREATMENT PLANTS TABLE OF CONTENTS PART I GENERAL 7-01. SCOPE OF THESE INSTRUCTIONS 7-02. INDUSTRIAL WASTES 7-03. DESIGN PROCEDURE 7-04. ENVIRONMENTAL SANITATION 7-05. TEMPORARY DISPOSAL OF SEWAGE a. Sedimentation and Chlorination b, Plain Sedimentation and Lime Treatment 7-06. USE OF EXISTING SEWAGE TREATMENT PLANTS Municipal Plants b. Government Plants 7-07. SITE SELECTION FOR SEWAGE TREATMENT PLANTS 7-08. DEGREE OF TREATMENT AND SELECTION OF pESIGN FACTORS a. Gene r a 1 b. Factors Affecting Treatment c_. Partial Treatment cK Design Factors 7-09. CONSERVATION OF CRITICAL MATERIALS PART II SANITARY SEWERS 7-10. DEFINITIONS a. Sewerage Works b. Collecting System c. House Sewer d. Lateral Sewe r e_. Branch Sewer Ma in Sewer Trunk Sewer jh. Force Main _i . Out fall Sewe r . Out 1 e t Pipe Inverted Siphon REPRINT INCLUDES ADDENDA TO JULY 1944. E. M. CHAPTER VII JANUARY 1943 7-11. SPECIFICATIONS 7-12. STANDARD DETAILS 7-13. BASIS OF DESIGN a. Sewage Quantities b. Peak Flow for Sewer Design Future Capacity 7-14. SIZES AND SLOPES Size Slopes c_. Hydraulic Design 7-15. SEWER LAYOUT AND ARRANGEMENT OF STRUCTURES Sewers b. Manholes c_. Flush Tanks _d. Cover e_. Limitations on Use of Sanitary Sewers f. Cross-Connections g_. Building Connections 7-16. GREASE TRAPS 7-17. MATERIALS FOR SANITARY SEWERS a_. Type of Materials b. Concrete Sewer Pipe c_. Pipe Alternates 7-18. SEWER PIPE JOINTS 7-19. MANHOLES jj_. Manhole Walls b. Manhole Foundations c. Invert Channels d. Manhole Steps e. Manhole Frames and Covers 7-20. SEWER TRENCH LOADING 7-21. FORCE MAINS 7-22. LAYOUT MAPS E. M. CHAPTER VII JANUARY 1943 7-23. DESIGN ANALYSIS PART III SEWAGE PUMPING STATION 7-24. GENERAL 7-25. LOCATION OF SEWAGE PUMPING STATIONS 7"26. PUMPING STATION CAPACITY a_. Rates of Sewage Flow • _b. Reserve Capacity 7-27. SELECTION OF PUMPING UNITS 7-28. STORAGE WELL 7-29. PUMP CHARACTERISTICS 7-30. OVERFLOWS 7-31. STANDBY POWER 7-32. SURGE PROTECTION 7-33. DESIGN ANALYSIS PART IV SEWAGE TREATMENT PLANTS 7-34. GENERAL 7-35. ELEMENTS OF SEWAGE TREATMENT PLANTS a. Screens . Grit Ch ambers c. Measuring Devices d. Preliminary Sedimentation Tanks e. Biological Processes f. Final Sedimentation Tanks jg_. Chlorination Plant h. Sludge Disposal Structures _i_. Plant Sewers and Piping j. Laboratory and Control House 7-36. SEWAGE FLOWS a_. Average 24-Hour Sewage Flows b. Average 16-Hour Sewage Flows c. Maximum 4-Hour Sewage Flows d. Minimum 4-Hour Sewage Flows e. Extreme Peak Sewage Flows E. M. CHAPTER VII JANUARY 1943 7-37. SEWAGE CHARACTERISTICS JL* Airfields, Camps and Cantonments _b. Plants, Ports and Storage Projects 7-38. CAPACITY OF SEWAGE TREATMENT PLANTS .a. Initial Design Capacity b. Capacity Factor 7-39. ARRANGEMENT OF UNITS 7-40. HYDRAULIC DESIGN 7-41. SCREENS 7-42. GRIT CHAMBERS 7-43. MEASURING DEVICES 7-44. PRIMARY SEDIMENTATION TANKS 7-45. TRICKLING FILTERS a_. Determination of Applied B.O.D. _b* Low Capacity Trickling Filters c_. High Capacity Trickling Filters 7-46. ACTIVATED SLUDGE 7-47. CONTACT AERATION _a. Tank Design _b. Tank Capacity _c. Air Requirements 7-48. FINAL SEDIMENTATION TANKS a. Requirement _b. Final Sedimentation Tank Design 7-49. SLUDGE DIGESTION TANKS _a. Capa cities _b. Disposal of Supernatant Liquor 7-50. SLUDGE DISPOSAL 7-51. DESIGN OF SLUDGE DRYING BEDS E. M. CHAPTER VII JANUARY 1943 7-52. IMHOFF TANKS fL • Sedimentation Compartments b.* Sludge Compartments 7-53. SEPTIC TANKS a. Design of Septic Tanks b . Dos ing Tank 7-54. SUB-SURFACE IRRIGATION iL* Design of Sub-Surface Irrigation 7-55. LEACHING WELLS 7-56. SUB-SURFACE SAND FILTERS a_. Design 7-57. SOIL ABSORPTION TEST 7-58. CHLORINATION _a . Points of Application _b. Chlorine Contact Tank 7-59. MECHANICAL EQUIPMENT Sludge Removal _b_. Scum Removal _c. Sludge and Scum Pumps d_. Digestion Tanks Flame Protection f_. Dr a ins 7-60. OPERATING INSTRUCTIONS 7-61. MANUFACTURER’S GUARANTEE AND SERVICE INSPECTION AND TEST 7-62. SEWAGE TREATMENT PLANT LABORATORY 7-63. DESIGN ANALYSIS APPENDIX “A” CLASSIFICATION OF SEWAGE TREATMENT PLANTS APPENDIX "B” RECOMMENDED LABORATORY FURNITURE FOR ARMY SEWAGE TREATMENT PLANTS E. M. CHAPTER VII JANUARY 1943 APPENDIX “C” RECOMMENDED LABORATORY EQUIPMENT FOR ARMY SEWAGE TREATMENT PLANTS APPENDIX “D” RECOMMENDED LABORATORY CHEMIC\LS ” APPENDIX “E” TOOL LIST FOR ARMY SEWAGE TREATMENT PLANTS EXHIBIT 1-DIAGRAM GIVING DISCHARGE OF PIPES BY RUTTER’S FORMULA, N=0.013 EXHIBIT 2-SEPTIC TANK FOR TEMPORARY SEWAGE DISPOSAL EXHIBIT 3-HOURLY SEWAGE FLOW VARIATIONS FOR ARMY CAMPS ENGINEERING MANUAL CHAPTER VII DESIGN OF SANITARY SEWERS, SEWAGE PUMPING STATIONS AND SEWAGE TREATMENT PLANTS PART I GENERAL 7-01, SCOPE OF THESE INSTRUCTIONS: These instructions relate to the collection, treatment and disposal of domestic sewage and such other organic wastes, including laundry wastes, as might be found normally in sanitary sewers serving War Projects of all types. The design of storm water drains is not included in these instructions. Storm water or surface run-off should not be discharged into sanitary sewers. 7-02, INDUSTRIAL WASTES: In general, industrial wastes such as pickling liquids, caustic solutions and other wastes from manufacturing plants should not be combined with domestic sewage and special provision for separate treatment of such wastes should be provided, if treat- ment is required. However, in certain cases, it may be feasible and economical to combine the domestic sewage with the industrial waste for joint treatment and disposal. The hydraulic factors of design for sanitary sewers also apply to conduits carrying industrial wastes. In some cases, the industrial wastes may be of such nature as to require the use of special materials for con- duits. 7-03. DESIGN PROCEDURE: The development of sewer plans, of necessity, must await the final site plan and the completion of field surveys to obtain the necessary topography. In general, however, investigations relating to location of sewage treatment works, the degree of sewage treatment required, the type of plant to be designed, etc., can be completed simultaneously with the development of the site plan. The treatment of sewage is a highly specialized service and a properly qualified sanitary engineer should be employed on the engineering design of the sewage treatment plant. 7-04. ENVIRONMENTAL SANITATION: Where conditions resulting from relatively large in- creases in population in the vicinity of the project so require, adequate measures for safeguard- ing public health in the environment should be taken. This may require cooperation with State and local authorities having jurisdiction and with the United States Public Health Service. Among the more important items to be considered are the following: housing, rooming, food supplies, restaurants, milk supplies, waterworks, sewerage and sewage disposal, public comfort stations, garbage and refuse collection and disposal, and street cleaning. Particular attention should be given to any shallow water or swampy areas within one mile of the project, and proper provisions made for mosquito abatement. Consideration of such conditions should be given during the con- struction period as well as the period of occupancy. 7-05. TEMPORARY DISPOSAL OF SEWAGE: In some instances, temporary treatment of sewage is necessary at War Projects during the construction period, or to provide for occupancy of the project prior to the completion of the sewage treatment plant. JL* Sedimentation and Chlorination: Whenever possible construction should be scheduled to provide for the completion of the primary sedimentation tanks so that these can be placed in service prior to the completion of the remainder of the plant and the sewage given partial treat- ment. In such cases it is usually possible to provide chlorination for the sterilization of the sedimentation tank effluent prior to discharge into the receiving water course. In cases where it is necessary to provide temporary treatment prior to the completion of any portion of the E. M. CHAPTER VII JANUARY 1943 sewage treatment plant it may be necessary to construct a septic tank at a convenient location and arrange for applying chlorine to the tank effluent at the rate of 100 pounds per million gallons. Such a septic tank can he excavated in earth, lined with timber sheeting and provided with a wooden roof. The cost of the temporary installation should be kept at a minimum and re- liance placed on the heavy chlorination (at the rate specified above) of the tank effluent to prevent a local nuisance and menace to health. J2* PIa*n Sedimentation and Lime Treatment; A relatively high degree of purification can be obtained by the application of hydrated lime to the raw sewage at the plant inlet. This requires the installation of a chemical feeder to feed the lime. Mixing of the lime with the sewage can be accomplished through a Parshall Flume. Sufficient lime should be added to develop a causticity of 10 to 20 p.p.m. This will result in the precipitation of the calcium and mag- nesium hi carbonates, which when settled will carry with them the suspended solids of the sew- age. The amount of lime required will vary from 500 to 1500 pounds per million gallons of sew- age depending on the hardness of the carriage water. This treatment will result in the removal of approximately 80 to 90 per cent of the suspended solids and a reduction of total bacteria in the same proportion. The reduction in B.O.D. will be from 60 to 70 per cent. This treatment can be used in conjunction with the primary sedimentation tanks if they are completed or the settling may be accomplished in a temporary septic tank, such as that described in 7-05 a above and shown on Exhibit No. 2. The volume of sludge to be handled will be substantially greater than the amount of settleable sludge solids because of the mineral precipitates but since the sludge is caustic it can be pumped into lagoons or burial pits without serious nuisance. If the digesters are completed they can be used to receive the lime treated sludge. This sludge will be beneficial in promoting alkaline digestion after the plant is placed in normal opera- tion. The excess lime treatment followed by plain sedimentation is not considered desirable for permanent treatment. Large quantities of lime would be required and the discharge of heavily treated effluents over a period of time would result in the accumulation of lime de- posits in the receiving water course. 7-06. USE OF EXISTING SEWAGE TREATMENT PLANTS: 3." Municipal Plants: For War Projects located adjacent to fairly large cities, in- vestigation should be made of the city’s sewage facilities to determine whether they are large enough to handle the flow from the project, assuming a reasonable increase in city requirements, and whether the city officials are favorably inclined toward handling the sewage at a reason- able cost to the Government for such services. These investigations should cover the prac- ticability of such a connection and whether the sewage will require pumping, or can be delivered to the city’s system by gravity. b. Government Plants: If there is an existing sewage treatment plant under the juris- diction of the War Department, or other Governmental Agency, which is accessible and which mi gjh t be suitable wi th or without enlargement, an investigation should be made to determine its capacity and condition and the possible arrangements that might be made for its use. 7-07. SITE SELECTION FOR SEWAGE TREATMENT PLANTS: Sites for sewage treatment plants should be carefully selected. The topography and location of the receiving stream will usually determine the location. Plants should preferably be located as far as practicable from buildings, private dwellings and travelled ways and consideration should be given to the direction of prevailing winds. Plants should be located where they will not interfere with military operations and should be at a safe distance from rifle and artillery ranges. If pos- sible, sites should be located above high water, but flood protection should be provided if required. Sufficient space should be available for a convenient arrangement of plant struc- tures and for possible future extensions to the plant. E. M. CHAPTER VII JANUARY 1943 7-08. DEGREE OF TREATMENT AND SELECTION OF DESIGN FACTORS: a. General: The sewage treatment plant should, if practicable, be designed to meet the requirements of local and State Health Departments, particularly as to degree of treatment and disposal of effluent and to this end the State Sanitary Engineer, or Director of the State Department of Health, should be consulted. b.* Factors Affecting Treatment: The degree of treatment required will depend upon the amount of diluting water available in the receiving stream during periods of minimum flow, the condition of the stream as regards pollution, and the use of the stream below the proposed point of discharge. Consideration should also be given to local practice with regard to the degree of treatment being provided by existing plants and the anticipated peric of occupancy of the proj ect. c. Partial Treatment: Where the effluent from the sewage treatment plant is to be dis- charged into a relatively large stream with a flow sufficient to provide a minimum dilution of about four (4) c. f.s. of stream flow per 1,000 population, sedimentation tanks with chlorina- tion will usually be sufficient. This partial degree of treatment may be suitable in cases where the effluent is to be discharged into tidal waters, or finally disposed of by irrigation on land. cl. Design Factors: If a greater degree of treatment is required, consideration should be given to operating requirements and the simplest type of plant should be used that will give the desired results. Where more than partial but less than complete treatment is required single stage high capacity filters can be used to good advantage. Treatment by the activated sludge process, standard rate trickling filters or multi-stage high capacity filters will pro- vide complete treatment where required. See paragraph 7-09 below. 7-09. CONSERVATION OF CRITICAL MATERIALS: Current policies of the War Department with respect to the conservation of critical materials must be strictly observed in the desi gi of sewerage systems and sewage treatment works. Plants should be simplified as much as possible and preference given to designs and types of treatment which require the use of a minimum amount of mechanical equipment, reinforcing steel and other items * critical materials. Where filter stone can be secured at a reasonable cost, standard rate filters, requiring a minimum amount of mechanical equipment, should be given preference. The use of high capacity filters and other types of treatment requiring greater amounts of mechanical equipment and other critical mater- ials should be confined to localities where stone is not available or where space limitations and other factors require the use of such processes. To avoid delays in securing delivery of equipment, every effort should be made to utilize types of equipment which can be supplied by several manufacturers. It *s essential that sewage t; 'atment facilities, where definitely needed, be ready for operation at the time of initial project occupancy. The ability of equip- ment manufacturers to make delivery within the required time must be carefully investigated prior to making commitments for the purchase of mechanical equipment. E. M. CHAPTER VII JANUARY 1943 PART II SANITARY SEWERS 7-10. DEFINITIONS: —* Sewerage Works; All construction for collection, transportation, pumping, treat- ment and final disposition of sewage. il* Collecting System: All sewers and appurtenances from the house to the outfall, £• House Sewer: A pipe conveying the sewage from a single building to a common sewer or point of immediate disposal. d. Lateral Sewer: A sewer which discharges into a branch or other sewer and has no other common sewer tributary to it. £,• Branch Sewer: A sewer which receives sewage from a relatively small area. f« Main Sewer: A sewer which receives one or more branch sewers as tributaries, 6» Trunk Sewer: A sewer which receives many tributarv branches and serves as an out- let for a large territory. h» Force Main; A pipe line carrying sewage under pressure from a sewage pumping station. _i_* Outfall Sewer: A sewer which receives the sewage from the collecting system and conducts it to a point of final discharge or to a disposal plant. _j. Outlet Pipe: A pipe which conveys the effluent from a treatment plant to its final point of disposal. k. Inverted Siphon: A sewer depressed below the hydraulic grade line so that the pipe or pipes are full at all times. NOTE: Pipe sizes should be so selected as to pro- vide flow velocities sufficient to prevent deposits or to scour out any deposits which might develop. 7-11. SPECIFICATIONS: Current issue of Section XXVII, Specifications for Theater of Operations and Mobilization Construction for Sanitary Sewers, Office of the Chief of Engineers, will be followed, insofar as applicable, to the materials selected. In cases where the materials and methods, approved for the work, are not covered by these Specifica- tions, suitable specifications for the work should be prepared. 7-12. STANDARD DETAILS: Standard details of construction items are shown on Stand- ard Drawing No. 672-243, O.C.E. These standard details may be modified to fit local condi- tions where such modification is desirable, subject to the approval of the District Engineer. E. M. CHAPTER VII JANUARY 1943 7-13. BASIS OF DESIGN: —• Sewage Quantities: Average daily sewage flows to be used for the design of collecting lines may be assumed as follows: Gallons per Capita per Day Type of Unit Permanent Posts Mobili- zation Type T. of 0. Type Field Training Camps Airfields, Camps, Canton- ments and Troop Facilities 100 70 50 35 Hospital Units 100 100 85 70 Plant, Port and Storage Proj ects (Civilian War Workers) 30 per 100 for 3 hour shift resident personnel Where unusual ground water conditions are known to exist an allowance of 10,000 gallons per mile of sewer per day may be added to the above for infiltration. (NOTE: The above per capita sewage quantities include laundry waste incidental to launder- ing for the resident population and no additional allowances will be made for such waste except in special cases. It is anticipated that the sewage treatment plant will be capable of treating the laundry waste together with the sanitary sewage and pretreatment of laundry waste will be provided only where specifically authorized. Standard plans for the construction of plants for the pretreatment of laundry waste will be furnished where such treatment is authorized^) b. Peak Flow for Sewer Design: The tributary population will be based on the full capacity of all buildings within the tributary areas and will include all civilian personnel. For plant, port and storage projects determination of peak flows should take into consideration maximum rates during the period the greatest number of workers are on duty. All sewers should be designed to handle peak flows based on the following: Tributary Ratio of Peak Population To Average Flow 1,000 3.7 2,000 3.66 3,000 3.62 5,000 3.55 7,000 3.47 10,000 3.34 15,000 3.18 20,000 . 3.05 30,000 2.79 35,000 2.70 40,000 2. 58 50,000 2.55 E. M. CHAPTER VII JULY 1944 £' Future Capacity; Additional capacity to provide for population increases will not be considered for lateral and branch sewers where the areas served are fully developed. In the design of long outfall sewers and main sewers serving areas susceptible of further de- velopment additional capacity should be provided by applying the capacity factors set out in Paragraph 7*37. 7-14. SIZES AND SLOPES: _a. Size: House sewers should not be less than 6 inches in diameter. The minimum size of sewers other than house sewers should be 8 inches. —* Slopes: In general, all sewers should be laid on slopes sufficient to provide a minimum velocity of 2 feet per second when flowing full or half-full. However, in unfavorable terrain, velocities of 1.5 feet per second may be used if excessive depths of sewer trench or the use of sewage lift stations can be eliminated thereby. The following slopes for various sizes of sewers’will produce satisfactory velocities: Slope in Slope in Diameter in ft./lOOO ft. for ft./lOOO ft. for Inches Velocity of 2 ft,/sec. Velocity of 1.5 ft./sec. 6 6.0 3.6 8 4.0 2.3 10 2.9 1.6 12 2.2 1.2 15 1.5 0.86 18 1.2 0.67 21 0.95 0.53 24 0.80 0.44 27 0.67 0.38 30 0.58 0.33 (NOTE: There is a tendency on the part of some designers to increase the size of the sewer where flat grades are required in order to maintain a theoretical minimum velocity of 2 feet per second. Actually the increased pipe size will result in a decrease in a depth of flow such that the resultant velocity is no more than would be obtained by using the smaller sewer at the same slope. The net result of increasing the pipe sire is to increase the cost and this practice should be avoided.) £. Hydraulic Design; Design capacities of sewers should be computed byKutter’s formula using n = 0.013 with pipe flowing full. A diagram (See Exhibit No. 1) giving discharge of pipes by Kutter's formula, n s 0.013, is inserted herein for ready reference. 7-15. SEWER LAYOUT AND ARRANGEMENT OF STRUCTURES: a. Sewers: Where otherwise feasible, sewers should not be built longitudinally under paved roadways, and pavement crossings should be kept to the minimus. The cutting of roadways for house sewers should be avoided where practicable. At railroad crossings, special construction consisting of metal pipe or sewer pipe encased in concrete should be used. ♦Sewer mains will not be installed in the same trench with water mains, but shall be located si* (6) feet or more from them horizontally and on opposite sides of roadways where practicable. Where sewer and water mains cross, the sewer will, if possible, be located below the water main. If conditions necessitate, a gravity sewer may cross over a water main, provided the sewer for ten (10) feet either side of the crossing is con- structed of cast iron, steel or other pressure pipe. Sewers under pressure such as force mains, in- verted siphons, etc., will in all cases cross under and be installed not less than two (2) feet be- low the water aain.^ ♦Single asterisks appear before and after new or revised material. E. M. CHAPTER VII JULY 1944 b. Manholes: Manholes should be constructed at the end of each lateral, and at each change of direction, slope or grade. The distance between manholes should not exceed 400 feet, except on long outfall sewers of larger pipe sizes where distances of 600 feet be- tween manholes may be used. £.‘ Flush Tanks: Flush tanks are not considered advisable or necessary in sanitary sewer systems and will be used only in connection with Types Lt-F-T and Lt-G-T Latrines as shown on Standard Drawings Numbers T.O.-700-6625 and T.O.-700-6626. ii* Cover: In general, sewers should not have less than 2 feet of cover to provide protection from traffic. For allowable sewer trench loadings see Paragraph 7-20. Limitations on Use of Sanitary Sewers; The following wastes should not be per- mitted to enter the sanitary sewers, but should be discharged through separate drains; (1) Storm water. (2) Waste water from hydraulic gasoline storage systems. (3) Waste water from garage and shop floor drains. (4) Waste water from wash racks. If Cross-Connections: There shall be no possible or actual physical connection be- tween sewer and water supply systems. g. Building Connections: All building connections into sewer lines less than 24 inches in diameter should be made only with commercially manufactured Wye branches or Tees. Where convenient, such connections may be made directly into manholes. The house sewer will be separated not less than six (6) feet horizontally from the water service pipe. 7-16. GREASE TRAPS: The removal of grease is necessary for the proper functioning of sewage treatment plants and will be accomplished by the installation of grease traps in mess halls and kitchens as outlined in Chapter XIV, Interior Utilities, of this Manual and speci- fied in Section XXXV, Specifications for Theater of Operations (Modified) and Mobilization Construction for Plumbing, Office of the Chief of Ehgineers. 7-17. MATERIALS FOR SANITARY SEWERS: ji. Type of Materials: In selection of materials for sanitary sewers, full con- sideration will be given to initial economy, speed of construction and the availability of local materials. In general, camps and cantonments are considered temporary construction and underground utilities should be constructed »>f materials to provide a useful life of at least five years. Vitrified clay sewer pipe may be used in all sizes for which it is readily avail- able. Unreinforced concrete sewer pipe may be used, in competition with vitrified clay, for sizes 24-inch and smaller, except where local conditions indicate that its use is inadvisable. Reinforced concrete pipe may be used for sizes over 24-inch, except where conditions are known to exist which would cause the severe disintegration of this material. b. Concrete Sewer Pipe; Conditions under which concrete pipe may not be used are as follows: (1) Where the sewer receives acid waste not sufficiently diluted with alkaline sewage. (2) Where acid subsoil may gradually attack and destroy the pipe, i.e., cinder fills. (3) Where local experience has indicated that concrete sewer pipe is not suitable. E. M. CHAPTER VII JANUARY 1943 £. Pipe Alternates: Where conditions indicate either vitrified clay sewer pipe or Portland Cement concrete pipe will be acceptable, specifications should be so drawn as to permit the use of either or both types. Where warranted by conditions of availability and economy, other materials may be used on approval by the District Engineer. District Engineers should make the following investigations to satisfy themselves as to: (1) Whether Portland cement concrete pipe has been installed in municipalities near their respective projects and has given satisfactory results. (2) Whether aggregates meeting Federal Specification No. SS-A.281, Grade MA” requirements, are available. (3) Whether manufacturers can comply with the Specification requirements as to machine manufacturing and curing. (4) Whether, if both types (vitrified terra cotta and cement concrete pipe) are specified, competition can be had. 7-18. SEWER PIPE JOINTS: Sewer pipe joints should preferably be made with hot poured bituminous material, preformed bituminous or plastic bituminous material. Cement mortar may be used on approval by the District Engineer, 7-19. MANHOLES: a. Manhole Walls: Manhole walls may be constructed of brick masonry, concrete block masonry or unreinforced monolithic concrete, depending on availability of materials, skill of available workmen and other considerations affecting economy. b. Manhole Foundations: Manhole foundations shall be of unreinforced concrete. c. Invert Channels; Invert channels may be formed in the concrete, built up with brickwork and mortar, constructed of half-tile, or made by laying pipe straight through the manhole with the top half broken out and removed after construction. The most practical and economical method under local conditions shall be used. d. Manhole Steps: In order to conserve metal, manhole steps should be omitted wherever possible. Access can be had by the use of a ladder. Where manhole steps are necessary they may be cast iron, wrought iron or ordinary steel rods. If cast iron they should be of a pattern readily available locally. If wrought iron or steel rods are used they should be not less than 3/4-inch diameter. e_, Manhole Frames and Covers: To conserve critical materials reinforced concrete frames and covers should be used in locations subjected to traffic. Unreinforced concrete and wood covers may be used in locations not subjected to traffic. E. M. CH AFTER VII JANUARY 1943 7-20. SEWER TRENCB LOADING: Where the loads in the sewer exceed those that can be safely carried by the pipe, and where required for wet soil conditions, concrete cradles will be used. Sewer trench loadings should be computed by the Mars ton-Anderson Formula as developed in Rjlletin 96, Iowa State College, Engineering Experimental Station, which is as follows: W = CwB2 where W = dead load on the pipe in pounds per lineal foot. W =. weight of ditch filling material in pounds per cubic foot, taken from Table B below. B= breadth of ditch in feet at the top of the pipe. H — height of fill in feet above the top of pipe. C= coefficient of load on pipe in ditches determined from the following Table A. TABLE A Ratio of depth to width H/B Value of the Coefficient C for Use in the Marston-Anderson Formula Damp Top Soil and dry and * wet sand Saturated Top Soil Damp Yellow Clay Saturated Yellow Clay 2.5 1.70 1.77 1.83 1.91 3.0 1.90 1.99 2.08 2.19 3.5 2.08 2.18 2.28 2.43 4.0 2.22 2.35 2.47 2.65 4.5 2.34 2.49 2.63 2.85 5.0 2.45 2.61 2.78 3.02 5.5 2.54 2.72 2.90 3.18 6.0 2.61 2.81 3.01 3.32 6.5 2.68 2.89 3.11 3.44 7.0 2.73 2.95 3.19 3.55 7.5 2.78 3.01 3.27 3.65 8.0 2.82 3.06 3.33 3.74 8.5 2.85 3.10 3.39 3.82 9.0 2.88 3.14 3.44 3.89 9.5 2.90 3.18 3.48 3.96 10.0 2.92 3.20 3.52 4.01 11.0 2.95 3.25 3.58 4.11 12.0 2.97 3.28 3.63 4.19 E. M. CHAPTER VII JANUARY 1943 TABLE B VALUES OF “w” WEIGHTS OF DITCH FILLING MATERIAL For USE IN MARSTON-ANDERSON FORMULA Material Wt. of Filling per Cubic Foot Partly compacted damp yellow clay 100 Dry Sand 100 Saturated Top Soil 110 Sand 120 Saturated Yellow Clay 130 NOTE: Allowances for live loads over sewer trenches are not made except under railroad tracks and other locations where metal pipe, concrete encasement or a protective conduit is re- quired. 7-21. FORCE MAINS: Sewage force mains will be constructed of cement asbestos, wood stave, cast iron or steel pipe of adequate strength to withstand the internal pressures and ex- ternal loads, and shall be water-tight. The line must be large enough to handle peak rates of flow without excess loss of head due to friction. In general friction losses through long force mains should not exceed 100 feet when the combination of pumps producing the maximum discharge are in operation. Consideration will be given to venting all summits in force mains, to provid- ing drainage at low points, and to protecting against surge in long lines. 7-22. LAYOUT MAPS: A layout map showing the entire collecting system, together with unit maps to a scale of 1 inch to 50 feet, should be prepared. Distribution of sewer layout maps should be as provided in Section 1, Chapter XXIII of this Manual, 7-23. DESIGN ANALYSIS: A design Analysis, required by Paragraph 703.33 a. (Revision of November 2, 1942) Orders and Regulations, Corps of Engineers, will be prepared to accompany all plans and specifications for sanitary sewers. The design analysis will indicate the total trib- utary population to be served by each main sewer and the method used in determining sewer sizes. E. M. CHAPTER VII JANUARY 1943 PART III SEWAGE PUMPING STATIONS 7-24. GENERAL: Sewage pumping stations may be required to pump the sewage from areas which cannot be served by the main gravity system or at sewage treatment plants where pumping is required to handle the sewage through the plant. Sewage pumping stations, in general, will comprise a screen, a sump or storage well and a dry well for the pumping equipment. 7 -25. LOCATION OF SEWAGE PUMPING STATIONS: The location of sewage pumping sta- tions serving portions of a system will usually be determined by the topography. Such stations should be located as far as practicable, from buildings, but should be readily accessible from an improved road. Sewage pumping stations at treatment plants will usually be constructed ad- jacent to and in connection with the other plant elements. 7-26. PUMPING STATION CAPACITY: _a. Rates of Sewage Flow: The average rate of flow for which pumping capacity is to be provided should be based on the per capita sewage flows stated in Paragraph 7-12 a above. The capacity of the pumping station should be ample to handle maximum rates of sewage flow as outlined in Paragraph 7-12 b above. The design should be such that there will not be long in- tervals between the operation of a pump during periods of minimum flow, especially if such in- termittent discharge will adversely affect the operation of a sewage treatment plant by intro- ducing high rate flows at infrequent intervals. b. Reserve Capacity: Additional capacity to provide for population increases will not be considered for sewage pumping stations serving areas which are fully developed. If the pump- ing station serves an area which may be expanded it is wise to provide space in the building for the installation of an additional or larger pump at a later date. In the design of sewage pump- ing stations constructed in connection with sewage treatment plants additional capacity should be provided by applying the same Capacity factor used in the design of the sewage treatment works. 7-27. SELECTION OF PUMPING UNITS: Horizontal or vertical centrifugal pumps are usually best suited for sewage pumping installations. For small stations serving populations less than 1500, twin pneumatic sewage ejectors or ejector type pumps are acceptable and may be used in lieu of centrifugal putnps. The use of the ejector type of equipment eliminates the need of screens and the units can frequently be installed in a pit entirely below ground thereby eliminating the need of a pumping station. For stations serving populations of 5,000 or less, two pumping units, each capable of handling the maximum rates of sewage flow will probably suf- fice. For stations serving populations greater than 5,000 three or four pumping units will be required, depending on the head capacity characteristics of the station as a whole. The mini- mum size of centrifigual pumps should be such as to pass a 2-inch sphere with 4-inch suction and discharge, piping and valves. All pumps will normally be actuated by float controlled switches. 7-28. STORAGE WELL: The storage well should be carefully designed to eliminate the possibility of sludge deposits. In order to prevent the sewage from becoming septic due to long retention during periods of minimum flow the capacity of the storage well should be large enough only for the proper operation of the pumps. For pumping stations serving a population of less than 3500 the storage well should provide about ten minutes storage at the average rate of flow. For stations serving a population greater than 3500 storage of three to five minutes at the average rate of flow is sufficient. E. M. CHAPTER VII JANUARY 1943 7-29. PUMP CHARACTERISTICS: If the pumps discharge intp an adjacent conduit of ample size or directly into the primary sedimentation tank at the sewage treatment plant there will be no increase in friction head when pumping at increased rates of flow and all pumps in the station may be operated together to deliver the peak rates of flow. If the pumps discharge into a long force main there will be an increase in friction head when the rate of flow is in- creased. This will create a total head higher than the rated head of the individual pumping units so that not more than one or possibly two pumps will be capable of operating effectively at one time. Under such conditions it will be necessary to provide one pump having head capa- city characteristics capable of handling the maximum rate of flow. 7-30. OVERFLOWS: Whenever possible an overflow should be provided from the storage or sump well to a point of outlet to operate only in case of power outages or short periods of shutdown. The elevation of the overflow must be low enough to prevent the backing up of sew- age into buildings. Generally the operation of an overflow into an adjacent water course dur- ing a power outage will not create a serious menace to public health because of the infrequency of use and the overflow should be omitted only in cases where a water supply would be definite- ly endangered. 7-31. STANDBY POWER: Standby power will be required only where it is impossible to provide a suitable overflow. Where standby power is required one pumping unit capable of handling the peak flow should be equipped with a combination head and standby gasoline engine. 7-32. SURGE PROTECTION: When the location of the pumping station requires a force main of several thousand feet, provision should be made for protection against surge and for drainage of the force main. A suitable air chamber at the pumping discharge will usually provide adequate surge protection. 7-33. DESIGN ANALYSIS: A design .Analysis, required by Paragraph 703.33 a. (Revision of November 2, 1942) Orders and Regulations, Corps of Engineers, will be prepared to accom- pany all plans and specifications for sewage pumping stations. The design analysis will in- dicate the total tributary population to be served by the pumping station and the basis of design for each component unit. E. M. CHAPTER VII JANUARY 1943 PART IV SEWAGE TREATMENT PLANTS 7-34. GENERAL: The basic design data contained herein applies to the planning of sewage treatment plants of all sizes. It is important that designs be simplified as much as possible and preference given to types of treatment which require the use of a minimum amount of mechanical equipment, reinforcing steel and other items of critical material. It is anti- cipated that sewage treatment plants will be capable of treating the normal laundry waste to- gether with the sanitary sewage. Plants for the pretreatment of laundry waste will be con- sidered only at locations where existing treatment works are overloaded and where the pretreat- ment of the laundry waste will make it unnecessary to enlarge the sewage treatment plant. At certain Ordnance Plants and Chemical Warfare Plants there may be unusual industrial wastes which require special treatment involving the neutralization of chemical compounds used in the manufacturing processes. 7-35. ELEMENTS OF SEWAGE TREATMENT PLANTS: Listed below are the elements that make up sewage treatment plants. A plant designed to give partial treatment may include screens, grit chambers, measuring devices, all of the types of preliminary sedimentation tanks listed under subparagraph _d. of 7-58, “Chlorination,” all of the sludge disposal facilities listed under _h and the auxiliary items listed under JL_ and j_ below. A plant designed to pro- vide complete treatment will include in addition to the above one of the biological processes listed under subparagraph _e_ below and one of the types of final sedimentation tanks listed under subparagraph _f_. It will be seen that a treatment plant may consist of a number of dif- ferent combinations of treatment methods. a. Screens: Screens remove large suspended and floating matters, such as sticks, rags and miscellaneous materials that would clog pumps or cause excessive scum. b_. Grit Chambers: Grit chambers remove sand and similar heavy gritty materials that would injure pxjmps or clog sludge pipes. c_. Measuring Devices: These devices measure the amount of sewage flowing into or out of the plant. In large plants sludge may also be measured. Such measurements provide val- uable information to the plant operator and lead to obtaining better effluents. jd. Preliminary Sedimentation Tanks: These remove a large proportion of the settleable solids and thus reduce the load of organic solids preliminary to treating the partially clari- fied sewage by biological means. (1) Plain or Single-story with sludge removing equipment: These tanks allow the solids to settle on the tank bottom where moving blades pxish i t to a hopper at the center or at one end. From there the sludge is pjumped or drawn by gravity to the sludge digestion tank. (2) Plain or Single-story with Hoppered Bottoms: These tanks allow the sludge to settle into hoppers from which it is withdrawn to the sludge digestion tank. (3) Imhoff or Two-story: These tanks have an upper story which serves as a sedi- mentation tank. It has a V-shaped bottom with a slot at the px>int of the V through which the solids settle to the lower story. In the lower story the sludge is retained until it is di- gested. E. M. CHAPTER VII JANUARY 1943 e. Biological Processes: These are also known as secondary treatments because they provide opportunities for bacteria to stabilize or oxidize the organic matter remaining in the sewage after the preliminary treatment. They allow intimate contact with a medium that contains a bacterial growth and obtains oxygen from the atmosphere. (1) Standard or low capacity trickling filters: These are beds of crushed rock, gravel, or slag of relatively large size. The sewage trickles in a thin film over the stones which are coated with an organic film containing the aerobic oxidizing bacteria. (2) High capacity trickling filters: The only important differences between these and the standard filters are the greater dosing rate and the provision for recirculating fil- tered effluent back the filter. Some filters may have provision for forcing air through them. These filters depend more upon coagulation of colloidal sewage solids for their efficiency than do standard filters. More careful design of final settling tanks is therefore required. (3) Activated Sludge: In the activated sludge process settled sewage is passed through aeration tanks where it is brought into contact with previously developed activated sludge. Activated sludge is created by aerating with compressed air blown into it or by mech- anical agitation or by a combination of these methods. The sludge contains aerobic bacteria which act upon the organic matter. The sludge assimilates some of the organic matter and con- stantly increases in volume. The activated sludge is settled out in the final sedimentation tank, a portion of it being returned and mixed with the incoming settled sewage and a portion of it wasted to the digester. (4) Con tact -aeration: In this treatment the sewage passes through a tank con- taining submerged plates or large stones. Air is applied at the bottom of the tank and the rising bubbles set up aerobic conditions and promote an organic film on the surfaces which stabilize the organic matter of the sewage. (5) Other approved processes; These include sand filters, sub-surface irrigation and leaching pools. They are useful under favorable conditions and for small installations. _f. Final Sedimentation Tanks: These tanks separate coagulated solids or sludge, if treatment is by (_e_) above, from the sewage, leaving the clear, stabilized liquid as the ef- f luent. (1) Flat-bottomed Tanks: Tanks with sludge moving equipment are the same as those described under subparagraph (1) above. (2) Hopper-bottomed Tanks: These are the same as those described under subpara- graph _d (2) above. g. Chlorination Plant: Chlorination has several uses in sewage treatment. When used as a disinfectant it is usually applied in the effluent to kill pathogenic organisms remain- ing after other treatments. When used to prevent odors at the plant it is applied to the raw sewage where it both inhibits the growth of bacteria which form odorous gases and neutra- lizes those already formed. E. M. CHAFTER VII JANUARY 1943 h. Sludge Disposal Structures: Sludge is a by-product of all of the processes of sub paragraphs d_, e_, and _f_ above. It is unstable, large in quantity and high in water content. It is usually stabilized and reduced in quantity by anaerobic bacteria in digestion tanks. (1) Digestion Tanks: These are tanks which hold the sludge for the 6 to 12 weeks necessary for anaerobic digestion. Digested sludge is withdrawn from time to time from the bottom of the tank. Heating makes it possible to keep the sludge at the optimum temperature for more rapid digestion. (2) Sludge Pumping Facilities: These are necessary to return activated sludge to the aeration tank; to remove sludge from sedimentation tanks to the digestion tank; or to re- move sludge from the digestion tank to the sludge drying bed. Some of these processes in any one plant may be accomplished by gravity flow. (3) Sludge Drying Beds: After digestion sludge is inodorous and drainable. Sludge drying beds are constructed of sand underlain by gravel, and drained by open-jointed tile pipes. Sludge is run onto the bed and water drains away or is evaporated. J_. Plant Sewers and Piping: These comprise all of the sewer and piping connections between the various plant units. j_. Laboratory and Control House; A central building housing the electrical pumps, equipment controls, plant laboratory and operating records. A complete schedule of laboratory equipment for plants of various types is contained in Appendix “RM. 7-36. SEWAGE FLOWS: a.. Average 24-Hour Sewage Flows: The average daily sewage flow to be used for the de- sign of sewage treatment plants will be determined by multiplying the total tributary popula- tion, increased by the proper capacity factor, as set out in Paragraph 7-37 by the following per capita daily rates of flow: Type of Unit Gallons per Capita per Day Pe rmanent Pos ts Mobili- T. of 0. zation Type Type Field Trainin g Camps Airfields, Camps, Cantonments and Troop Facilities 100 70 50 35 Hospital Units 100 100 8 5 70 Plant, Port and Storage Projects (Civilian War Workers) 30 per 8 hour shi ft 100 for resident personnel Additional allowances should be included for ground water infiltration if provision has been made for ground infiltration in the design of the sewers. E. M. CHAPTER VII JANUARY 1943 b_. Average 16-Hour Sewage Flows: The sixteen hour average rate of flow will be 125 per cent of the average rate for 24 hours. c. Maximum 4-Hour Sewage Flows: The maximum 4-hour average rate of flow will be 17 5 per cent of the average rate for 24 hours. d. Minimum 4-Hour Sewage Flows: The minimum 4-hour average rate of flow will be 40 per cent of the average rate for 24 hours. • » 2 2 100 ml l f - 19 1 1 1 Low Form 100 ml S-24765 1 1 Dessicator, Schiebler, with plates, 250 mm S-25015 14560 8-600 6 Dishes, evaporating, Coors, porcelain, 150 ml S-2 5505 18575-2 8-690-C 2 I Files, triangular tapered, 4” S-32225 88325 9-725 12 6 Filter paper-No. 500 per pkg. of 100-9 cm S-32915 13250 9-795 2 12. 5 cm 1 » »» M 6 3 Flasks-Erlenmyer-Pyrex 500 ml S-34355 1490 5 10-040 6 3 Flasks 250 ml ” ft f • 2 1 Flasks, filtering, side tubulature 500 ml S-34375 1498 5 10-17 5 2 1 Flasks, Volumetric 1 liter S-34805 16220 10-200 1 I 500 ml ft It 2 1 250 ml It »• 4 2 200 ml ” ft It 2 1 100 ml ” ” t f 1 1 Flask, Volumetric, 200 ml - Large mouth for D. 0. S-34995 16290 10-240 1 1 Filter, Sedgewick, Rafter Graduated for B.O.D. Di io» S- 84015 29030 15-400 1 1 Plate, Spot, size 00 Plate, Porcelain S-70025 18600 13-745 S - 6998 5 18600 13-745 APPENDIX »C" (CONT'D.) E. M. CHAPTER VII JANUARY 1943 QUANTITY DESCRIPTION CATALOGUE NUMBERS Type c A & B >f Plant C D E. H. Sargent & Co. Central Scienti fic Co. Fisher Scienti fic Co. 2 1 Tongs, crucible, lock joint-91/” S-8 2205 19620 15-185 1 1 14” S-82215 99 99 2 1 Triangle, Nichrome 2” S-82445 19705 15-260 2 1 Wire Gauze-Chromel 4” x 4” S-85315 19960 15-585 20 10 Rubber tubing, medium wall pure gum per ft. lA" S-7 3505 18200 14-155 10 10 3/8” M II 99 10 10 Rubber tubing, Vacuum, *4” S-7 3535 18204 14-175 1 1 Filter Pump-Richards Size A 3/8” S-33565 13205 9-965 6 4 Bottles, dropping 30 ml S-8745 10535 2-980 1 1 Funnel Support - 4 place S-78815 19035 14-740 1 1 Brush, Test Tube Med. S-9995 1097 2 3-590 1 1 Brush, Flask Size B S-9965 10985 3-570 1 I Mortar 8s Pestle porcelain - 100 ram S-62235 17 380 12-960 6 3 Bottles - 5 gallon S-8435 10310 2-885 1 1 Still-Water, Stokes gas heated S-27645 12805 9-055 1 12 8 1 1 6 6 3 Chlorine Testing Set Automobile radiator hose for water seals per ft. Milk kettles, ivory enameled, seamless 4 qt. cap. (for sample storage) S-838 25 29 2 55 APPENDIX "C" (CONI'D.) E. M. CHAPTER VII JANUARY 1943 QUANTITY DESCRIPTION E. H. Sa r gen t fr Co. CATALOGUE NUMBERS Type o A fit E f Plant C D Central Fisher Scientific Scientific Co. ' Co. 2 Beakers, Pyrex, 2 liter S-4675 1426 5 2-540 2 2 1 >1 99 99 2 600 ml 99 ” 99 4 6 400 ml 99 99 99 4 6 250 ml 99 99 9 9 2 50 ml >1 99 99 lA Watch Glasses 115 mm 1 doz. S-8360 5 158 50 2-610 Bottles, Glass stoppered, Flint Glass, Mach. made. 12 6 32 oz. S-8345 10430 2-915 6 3 16 oz. 9 9 ” 99 72 24 8 oz. 99 99 99 36 36 A _ ** OZ . 2 1 Bottle Washing, Pyrex - 1000 ml S-9365 10710 3-395 2 1 Burettes, Geissler, Blue Line-50 ml S-10635 159 2 5-C 3-700 2 1 Burners, Tirril with Stabilizer S-12295 11025-C 3-960 2 1 Clamps, Burette, Spring Closing S-19045 12120 5-770 1/3 Clamps, pinch, 1 doz. S-19045 12180 5-850 3 2 Stoppers, rubber, assorted sizes, solid per lb. $1,00 S-7 330 5 18150 14-130 1 1 Cork Borer, brass set 1 to 6 S-2317 5 12460-B 7-845 12 6 Crucibles, Coors, size 1, wide form S-23665 18 535 7-955 12 6 Crucibles, Gooch, size 3, o.7 mm, perforation, Coors Porcelain S-24315 18565 8-195 APPENDIX "C" (CONT*Do) E. M. CHAPTER VII JANUARY 19 43 QUANTITY RECOMMENDED LABORATORY CHEMICALS FOR ARMY SEWAGE TREATMENT PLANTS. C D ITEM Type of Plant A & B ■ 18 Lbs, 9 Lbs. Sulphuric Acid, C. P. 18 Lbs. 9 Lbs. ” ” Tech. 6 Lbs. Hydrochloric Acid. 100 grams 100 grams Sodium Azide* 1 Lb. 1 Lb. Sodium Bicarbonate 1 Lb. Sodium Carbonate, Anhyd. C. P. 5 Lbs. 5 Lbs. Sodium Hydroxide Pellets U.S.P. 1 Lb. 1 Lb. Sodium Thiosulphate, Cryst. 1 Lb. 1 Lb. Potassium Iodide C. P. 1 oz. 1 oz. Potassium Bin-iodate C. P. 5 Lbs. 5 Lbs. Potassium Bichromate, Tech. 5 Lbs. 5 Lbs. Manganous Sulphate C. P. Va Lb. Va Lb. Potato Starch 1 oz. 1 oz. Methylene Blue (USP) *4 Lb. * Lb. Asbestos, Med. fiber, acid washed 5 Lbs. Ferric Chloride, C. P. Lump 5 Lbs, Copper Sulphate Cryst., Tech. % Lb. Va Lb. Chloroform - U.S.P. 100 grams Orthotolidine 100 ml Phenolphthalein Indicator 100 ml Methyl Orange Indicator Obtain in field - Ampules Calcium Hypochlorite 5 Lbs. 5 Lbs. Calcium Chloride, Anhyd. * For Secondary Treatment Plants Only. APPENDIX "D" E. M. CHAPTER VII JANUARY 1943 APPENDIX «E" TOOL LIST FOR ARMY SEWAGE TREATMENT PLANTS Minimum Requirements for Class A, B 8s C Plants Quant. Description Catalogue No. * 1 Wrenches, pipe, 8” 258 ZAO or equal 1 ” ” 12” 2512 ZAO ” ” 2 00 H 2518 ZAO ” ” 1 ” 24” 2524 ZAO ” ” 1 Wrenches, Open Double End Set of 9, %** to J” P 725 ZAO Series or equal 1 Wrenches, Socket, hex, set of 10 and handle, 7/16” to 1” P 21 ZAO • • 1 Wrench, Crescent Adjustable, 10” 710 ZAl ft 1 Vise, Combination jaw and pipe. Swivel base A 20444 ZA2 ” »» 1 Hammer, Blacksmith, 254 lb. 0272 ZAO • > 1 ” Ball pein #2 252 ZAO ft 1 ” Claw #1 211 ZAO ft 1 Pliers, Combination, 8” 26 GZAl ” ft 1 Screw Driver, 6” 26 ZAO ” ft 2 File, 10” Mill Bastard 3 ZA3 ft 1 Cold Chisel, 54” 200 ZAO • f 1 ” ” 1” extra long 205 ZAO ft 1 Hacksaw 1027 ZAl ft 1 Hacksaw Blades, doz. 1412 FLZA0 ” ft 1 Wrecking Bar, 24” 95 ZAO ft 1 Hand Saw, 26”, 8 point 80 ZA2-D8 ft * H. Channon Co. Cat. #166, Chicago, 111. Discharge of pipes, n = 0.013. (John H. Gregory.) Slope tin Slope in Feef per Thou5 and Discharge, DIAGRAM GIVING DISCHARGE OF PIPES BY KUTTER’S FORMULA, n= 0.013. Mote:- For Scale for a.5^t ddand /.§y divide Scale for Slope in Feet per Thousand by /a. EXHIBIT I - E.M. JAN.,1943 - CHAPTER VII WALES SIDING ' '' 1/2“ TO 2" OPEN JOINTS DEPENDENT ON SOIL SLOPE FROM TO OPEN ENDS- DRY LIME FEEDER POSTS JOIST INFLUENT SEWER PIPE SUBMERGED PORTS" BAFFLE BAFFLE- LIME STORAGE PARSHALL FLUME /SEWER PIPE •BRACES EACH WAY •BEAMS; WEIR EFFLUENT -SEWER PIPE DECKING ’ LAID l“ OPEN JOINTS NOTES1- 1. PROVIDE 12 HOURS DISPLACEMENT PERIOD FOR 24 HOUR AVERAGE RATE OF FLOW BASED ON ACTUAL POPULATION WITHOUT CAPACITY FACTOR. 2. LENGTH OF TANK SHOULD BE FROM 2 TO 3 TIMES THE WIDTH, AND AVERAGE LIQUID DEPTH FROM 6 TO 10 FEET. • WALES PLAN PROVIDE TRAPDOOR AT EACH END AND CENTER OF TANK DECKING. SLOPE SLOPE SIDING OPEN JOINTS DECKING JOIST -BEAM SECTION POST BRACES SEPTIC TANK ‘^CONCRETE FOR WALES TEMPORARY SEWAGE DISPOSAL FRAMING DETAIL NO SCALE EXHIBIT 2 E.M. JAN. 1943 CHAPTER VII SEE PARAGRAPH 7-05. a. AND b. HOURLY SEWAGE FLOW VARIATIONS FOR ARMY CAMPS HOURLY RATE OF FLOW IN PER CENT OF AVERAGE PER 24 HOURS MAX. RATES AV. RATES MIN. RATES NOON ** AVERAGE OF 7 DAYS 9-14-41 TO 9-20-41. AA AVERAGE OF 95 DAYS 6-13-41 TO 9-15-41. * AVERAGE OF 6 DAYS SELECTED FROM MONTHLY RECORD OF AUG., 1941. A AVERAGE OF 7 DAYS 7-24-41 TO 7-30-41. HOURS OF DAY EXHIBIT 3 E.M. JAN. 1943 CHAPTER VII