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1、BRITISH STANDARD BS 6297:1983 Incorporating Amendment No. 1 Code of practice for Design and installation of small sewage treatment works and cesspools (Formerly CP 302 and CP 302.200) UDC 628.314.2-181.4+696.138 Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:28:07 GMT+00:00 2006, Uncontro
2、lled Copy, (c) BSI BS 6297:1983 This British Standard, having been prepared under the direction of the Building Services Standards Committee, was published under the authority of the Board of BSI and comes into effect on 29 April 1983 BSI 01-1999 The following BSI references relate to the work on th
3、is standard: Committee reference SEB/19 Draft for comment 80/15003 DC ISBN 0 580 13123 8 Cooperating organizations The Building Services Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following: Association of District Councils*Gre
4、ater London Council Bath Manufacturers Co-ordinating CommitteeHeating and Ventilating Contractors British Gas CorporationAssociation British Ironfounders AssociationIncorporated Association of Architects and British Plastics FederationSurveyors* British Plumbing Employers CouncilInstitute of Plumbin
5、g British Precast Concrete Federation Ltd.Institution of Environmental Health Officers Builders Merchants FederationInstitution of Gas Engineers Building Services Research and InformationInstitution of Municipal Engineers* AssociationInstitution of Public Health Engineers* Chartered Institution of B
6、uilding ServicesInstitution of Water Engineers and Scientists* Clay Pipe Development Association LimitedLocal Authorities Organization Consumer Standards Advisory Committee of Metal Sink Manufacturers Association BSINational Brassfoundry Association Convention of Scottish Local Authorities*National
7、Coal Board Council of British Ceramic Sanitaryware National Federation of Building Trades ManufacturersEmployers Department of Health and Social SecurityNational Water Council Department of the Environment (PSA)*Royal Institute of British Architects* Department of the Environment (BuildingRoyal Inst
8、itution of Chartered Surveyors Research Establishment)Royal Society of Health* Department of the Environment (WaterScottish Development Department* Directorate)Trades Union Congress Department of the Environment (HousingWater Companies Association and Construction)* Domestic Solid Fuel Appliances Ap
9、proval Scheme The organizations marked with an asterisk in the above list, together with the following, were directly represented on the Technical Committee entrusted with the preparation of this British Standard: British Water and Effluent Treatment Plant Institute of Clerks of Works of Great Brita
10、in AssociationInc. Cement and Concrete AssociationInstitute of Water Pollution Control Institute of Building Control OfficersWater Research Centre Amendments issued since publication Amd. No.Date of issueComments 6150December 1990 Indicated by a sideline in the margin Licensed Copy: sheffieldun shef
11、fieldun, na, Tue Dec 05 01:28:07 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6297:1983 BSI 01-1999i Contents Page Cooperating organizationsInside front cover Forewordiii Section 1. General 1Scope1 2References1 3Definitions1 4Collection of information3 Section 2. Materials 5Notes on materials3 Sect
12、ion 3. Design 6Design: general4 7General requirements for tanks6 8Cesspools6 9Septic tanks7 10Preliminary treatment10 11Primary and secondary settlement tanks11 12Biological filters including rotating biological contactors, and secondary settlement tanks13 13Activated sludge units16 14Tertiary treat
13、ment (polishing) processes19 15Disposal of final effluent20 16Pumping22 17Automatic monitoring and alarm systems23 Section 4. Installation 18Installation23 Appendix A References to standards not included in the text25 Appendix B Relevant sections of statutes and regulations currently applicable to s
14、mall treatment works and cesspools26 Index41 Figure 1 Sewage treatment: broad options for small communities8 Figure 2 Typical septic tanks, two in series, separate, for populations of up to 3027 Figure 3 Typical septic tanks, two in series, separate, for populations of over 3028 Figure 4 Typical sep
15、tic tanks, two in series, combined, for populations of up to 3029 Figure 5 Typical septic tanks, two in series, combined for populations of over 3030 Figure 6 Twin inlets for tanks in excess of 1 200 mm wide31 Figure 7 Typical tank inlet (crested weir)32 Figure 8 Typical upward flow settlement tank3
16、3 Figure 9 Typical horizontal flow settlement tank 34 Figure 10 Typical rectangular biological filter 35 Figure 11 Typical circular biological filter36 Figure 12 Treatment on grass plots37 Figure 13 Typical upward flow clarifier38 Figure 14 Cross section of typical underdrain39 Figure 15 Typical slu
17、dge drying bed40 Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:28:07 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6297:1983 ii BSI 01-1999 Page Table 1 Filter medium capacity14 Table 2 Grading limits for 50 mm filter medium15 Table 3 Air supply17 Publications referred toInside back cove
18、r Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:28:07 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6297:1983 BSI 01-1999iii Foreword This code of practice, prepared under the direction of the Building Services Standards Committee, encompasses the subject matter previously covered by cod
19、es of recommended practice for small sewage treatment works, CP 302:1972, and for cesspools, CP 302.200:1949. CP 302 and CP 302.200 are withdrawn. The use of cesspools or of septic tanks without further treatment of their effluent is generally considered not to be good practice but it is recognized
20、that in some situations such installations are the only practicable means of dealing with sewage. The increasing and wider application of synthetic materials and the production of larger prefabricated (package) units has been recognized and the scope of the code has been extended to include treatmen
21、t units to deal with sewage from populations of up to 1 000 persons. New processes developed since the publication of the previous code, such as the rotary biological contactor, are now included and it is intended that the code should not inhibit the development and application of other suitable new
22、 processes. The code gives guidance for those experienced in the design of small sewage treatment works. However, it is recognized that not all works are regularly designed by such persons and it is strongly recommended that specialist advice should be sought where appropriate, including where groun
23、d conditions are difficult, where there are likely to be abnormal flow or pollution loads, and for the design of tanks, and biological or other processes. It is not within the scope of this code of practice to set out in detail the full operation and maintenance requirements of small sewage treatmen
24、t works. Adequate maintenance is essential for even the smallest works to ensure that it produces the standard of effluent required, and instructions for proper operation and maintenance should be provided by the designer. For general guidance see National Water Council Technical Paper No. 4 “The Op
25、eration and Maintenance of Small Sewage Works”. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. This code of practice represents a standard of good practice and takes the form of reco
26、mmendations. Compliance with it does not of itself confer immunity from relevant legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages 1 to 42, an inside back cover and a back cover. This standard has been updated (see copyright date)
27、and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:28:07 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:28:07 GMT+0
28、0:00 2006, Uncontrolled Copy, (c) BSI BS 6297:1983 BSI 01-19991 Section 1. General 1 Scope This code of practice deals with the design and installation of sewage treatment works suitable for the domestic discharge from domestic and industrial communities ranging from single households up to about 1
29、000 population equivalent and with the storage of sewage by means of a cesspool, the contents of which are periodically removed for disposal or treatment. Domestic discharges are taken to include those from schools, hotels, restaurants, etc. but the code does not deal with the treatment of trade eff
30、luents, or the effluent from chemical closets. General guidance only is given on good design and installation practice. Particular requirements will be determined by local conditions. The codes recommendations should be supplemented as required by skilled engineering advice based on a knowledge of s
31、ewage works practice and of local conditions. Materials for tanks and other structures are not indicated on the diagrams, which are included for guidance on general proportions and details of inlets, outlets and other features, and should not be scaled. 2 References The titles of the publications re
32、ferred to in this British Standard are listed on the inside back cover. A list of other standards of interest in this field is given in Appendix A. 3 Definitions For the purposes of this code of practice the following definitions apply. 3.1 activated sludge a flocculent microbial mass, produced when
33、 sewage is continuously aerated 3.2 aerobic action a biological process promoted by action of bacteria in the presence of dissolved oxygen 3.3 anaerobic action a biological process promoted by the action of bacteria in the absence of dissolved oxygen 3.4 baffle a device used in a tank to check eddie
34、s and promote a more uniform flow through the tank 3.5 biochemical oxygen demand (BOD) the amount of dissolved oxygen consumed by microbiological action when a sample is incubated, usually for 5 days at 20 C 3.6 biological filter a bed of relatively inert material (such as slag, moulded plastics, cl
35、inker, etc.) to promote or assist natural aerobic degradation of sewage 3.7 bottom water level (BWL) the minimum operating water level in a pump well or dosing chamber 3.8 cesspool a covered watertight tank used for receiving and storing sewage from premises which cannot be connected to a public sew
36、er and where ground conditions prevent the use of a small sewage treatment works including a septic tank 3.9 combined system a drainage system in which both foul and surface waters are conveyed in the same pipe 3.10 distributor a device for spreading settled sewage over the surface of a biological f
37、ilter 3.11 dosing chamber a small tank which receives settled sewage until the desired quantity has accumulated, when it is discharged automatically to the distributor of a biological filter 3.12 dry weather flow (DWF) when the sewage flow is mainly domestic in character, the average daily flow to t
38、he treatment works during seven consecutive days without rain (excluding a period which includes public or local holidays) following seven days during which the rainfall did not exceed 0.25 mm on any one day NOTEWith domestic sewage from industrial premises the dry weather flow should be based on th
39、e flows during five working days if production is limited to that period. Preferably, the flows during two periods in the year, one in the summer and one in the winter, should be averaged to obtain the average dry weather flow. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:28:07 GMT+00:0
40、0 2006, Uncontrolled Copy, (c) BSI BS 6297:1983 2 BSI 01-1999 3.13 effluent polishing (tertiary treatment) a further stage of treating sewage by removing suspended solids. Consequential removal of residual BOD may occur 3.14 filter medium the material of which the biological filter is formed and on
41、which a biological film containing bacteria and fungi develops 3.15 final effluent the effluent discharged from a sewage treatment plant 3.16 humus tank see secondary settlement tank 3.17 mixed liquor a mixture of sewage and activated sludge undergoing circulation and aeration in the aeration tank o
42、r channel of an activated sludge plant 3.18 mixed liquor suspended solids (MLSS) the concentration of dry solids in milligrams per litre of mixed liquor in the aeration tank or channel of an activated sludge plant 3.19 package plant a prefabricated factory-built sewage treatment installation 3.20 po
43、pulation equivalent the equivalent, in terms of a fixed population, of a varying or transient population, e.g. of a hospital or restaurant, based upon a figure of 0.060 kg BOD per head per day or 120 L per head per day 3.21 primary settlement tank a tank in which the majority of settlable solids are
44、 removed from the crude sewage flowing through it 3.22 rotary biological contactor a unit consisting of a series of closely spaced, parallel discs, mounted on a rotating shaft which is supported just above the surface of the waste water to be treated 3.23 scumboard a device used at the outlet end of
45、 a tank to retain scum and other floating material 3.24 secondary settlement tank a tank in which settlable solids or humus is separated from the effluent flowing through it from biological filters or an activated sludge plant 3.25 separate system a drainage system in which foul and surface water ar
46、e conveyed by separate pipes 3.26 septic tank a type of settlement tank in which the sludge is retained for sufficient time for the organic matter to undergo anaerobic decomposition 3.27 sewage the water-borne wastes of a community 3.28 storm sewage sewage flowing to a treatment works in wet weather
47、 or discharged from storm overflows, when the sewage is diluted with rainwater 3.29 sludge a mixture of solids and water produced during the treatment of waste water 3.30 sludge loading the mass of BOD applied daily per unit mass of activated sludge MLSS 3.31 specific surface a property of biologica
48、l filter media expressed as surface area per unit volume (m2/m3) 3.32 supernatant liquor the liquor in a settlement tank, lying between the deposited solids and any floating scum 3.33 suspended solids (SS) solids in suspension in sewage liquors as measured by filtration either through a glass fibre
49、filter paper followed by washing and drying at 105 C, or by centrifuging followed by washing and removal of the supernatant liquid Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 01:28:07 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6297:1983 BSI 01-19993 3.34 top water level (TWL) the maximum water level in a settlement tank, an aeration tank, or a sludge storage tank 3.35 water table the level below which the ground is saturated with water 4 Collection of information The following main items of basic information should be o