Design Guide for Community Water Systems - The Water, Sanitation ...

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connected directly to any sewer. Such chambers or pits shall be drained to thesurface of the ground or provided with sump.8.5. Installation of Mains.8.5.1. Standards.Specifications shall incorporate the provisions of the AWWA standards and/ormanufacturer's recommended installation procedures.8.5.2. Bedding.a. A continuous and uniform bedding shall be provided in the trench for allburied pipe. Backfill material shall be tamped in layers around the pipe,and to a sufficient height above the pipe that the pipe is adequatelysupported, stabilized, and protected. Rocks and hard objects larger thanone inch diameter found in the trench shall be removed for a depth of atleast six inches below the bottom of the pipe. Sand or other fine nonacidicgranular material should be used for pipe bedding in high trafficareas. As an alternative, a chipper may be used on the trencher to preparethe soil removed from the trench as bedding in high traffic areas.b. Width of trenches shall be at least four inches larger than the pipe'sdiameter.8.5.3. Cover.All water mains shall be covered with at least 42 inches of earth or otherinsulation to prevent freezing. Lesser cover depth may be accepted in certainareas as approved by the department.8.5.4. Blocking.All tees, bends, plugs, valves, and hydrants shall be provided with reactionblocking, tie rods, or joints designed to prevent movement. Pre-cast concreteblocks should not be used.8.5.5. Pressure and leakage testing.All types of installed pipe shall be pressure tested and leakage tested inaccordance with the latest edition of AWWA Standard .8.5.6. Disinfection.All new, cleaned, or repaired water mains shall be disinfected in accordancewith the latest edition of the AWWA Standard. The specifications shallAug. 29, 2003Page 152
include detailed procedures for the adequate flushing, disinfection, andmicrobiological testing of all water mains.8.6. Separation of Water Mains, Sanitary Sewers and Combined Sewers8.6.1. General.The following factors should be considered in providing adequate separation:a. Materials and type of joints for water and sewer pipes;b. Soil conditions;c. Service and branch connections into the water main and sewer line;d. Compensating variations in the horizontal and vertical separations;e. Space for repair and alterations of water and sewer pipes; andf. Off-setting of water mains around manholes.8.6.2. Parallel installation.Water mains shall be laid at least ten feet horizontally from any existing orproposed sewer. The distance shall be measured edge to edge. In cases whereit is not practical to maintain a ten-foot separation, the department may allowdeviation on a case-by-case basis, if supported by data from the design engineer.Such deviation may allow installation of the water main closer to asewer, provided that the water main is laid in a separate trench or on anundisturbed earth shelf located on one side of the sewer and on either case, atsuch an elevation that the bottom of the water main is at least 18 inches abovethe top of the sewer. In areas where the recommended separations cannot beobtained, either the waterline or the sewer line shall be constructed ofmechanical joint pipe or cased in a continuous casing.8.6.3. Crossings.Water mains crossing sewers shall be laid to provide a minimum vertical cleardistance of 18 inches between the outside of the water main and the outside ofthe sewer. This shall be the case where the water main is either above orbelow the sewer. At crossings, the full length of water pipe shall be located soboth joints will be as far from the sewer as possible but in no case less thanten feet. Special structural support for the water and sewer pipes may berequired. In areas where the recommended separations cannot be obtainedeither the waterline or the sewerline shall be constructed of mechanical jointpipe or cased in a continuous casing that extends no less than ten feet on bothsides of the crossing.8.6.4. Exception.Any variance from the specified separation distances in paragraphs 8.6.2.and8.6.3. must be submitted to the department for approval.Aug. 29, 2003Page 153
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Design GuideforCommunity Water Syst
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2.18. AUTOMATION. .................
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4.3.11. Waste Disposal. ...........
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CHAPTER 6 -- MINIMUM CONSTRUCTION R
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Maximum Hour Demand -- The amount o
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(This page is intentionally blank.)
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and deviations are subject to indiv
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(blank)Aug. 29, 2003Page viii
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a. A description of the nature and
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a. Hydrological data, stream flow,
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4. Be conducted under the same oper
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maintaining the new technology and
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1.2.1. Plans shall include:a. Suita
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name, number, effective date, publi
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e. The site will provide all-weathe
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chlorine residual by methods in "St
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etween them, a six-inch band of con
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a. Regulated recreational activitie
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e done to determine the degree and
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1. Pumping rate;2. Pumping water le
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sieve analyses of the water bearing
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e circulated in the annular space s
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emoved. Therefore, every well shoul
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3.2.6.4. Pitless well units.a. The
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SIZE (inches)6 id.8101214 od.161820
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Chapter 4 -- Tre atment4.0. General
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settling basins shall be not less t
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3. Shall have valves located outsid
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d. Be automatic. Timers on automati
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2. Uniformity coefficient not great
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j. During air scour, the backwash w
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. An easily readable meter or flow
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4.3.4. Design Pressure Drop or Tran
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4.3.9. Flow Meters.Totaling rate of
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utilized, shall be 1.0 milligrams p
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. Removal of precursors prior to ch
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5. Consideration shall be given to
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. Pre-treatment requirements. Iron,
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t. Housing. Bagged salt and dry bul
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4.7. Iron and Manganese ControlIron
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Where phosphate treatment is used,
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3. Series and parallel flow piping
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approval of the department before u
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contact time must be provided to co
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a. Sanitary sewers with the approva
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1. Obtain a letter of approval from
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6. The provisions for the final dis
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a. Missouri River or Mississippi Ri
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5.0.3. General equipment design.Gen
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minimize chemical dust created by t
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1. At least 30 days of chemical sup
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Page 126 and 127: 5.4.2. Acids.a. Acids shall be kept
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Page 134 and 135: possibility for overfeed.h. Protect
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Page 144 and 145: g. Water from pump gland drainage s
Page 146 and 147: 6.3. Pumps.6.3.1.Pumps shall be siz
Page 148 and 149: 6.4.2.2. Suction lines.Suction line
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Page 152 and 153: parameters: average winter (Decembe
Page 154 and 155: a. Overflows shall be sized to perm
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Page 158 and 159: largest pump out of service shall b
Page 160 and 161: 7.1.4. CostsAs part of the final en
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Page 164 and 165: provided on larger tanks as needed
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Page 172 and 173: 8.6.5. Force mains.There shall be a
Page 174: 8.11.2. Filling device.A filling de
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