1、BRITISH STANDARDBS EN 12255-16:2005Wastewater treatment plants Part 16: Physical (mechanical) filtrationThe European Standard EN 12255-16:2005 has the status of a British StandardICS 13.060.30g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g4
2、0g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 12255-16:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 19 December 2005 BSI 19 December 2005ISBN 0 580 47429 1National forewordThis Britis
3、h Standard is the official English language version of EN 12255-16:2005.The UK participation in its preparation was entrusted to Technical Committee B/505, Wastewater engineering, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its
4、 secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Ca
5、talogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand
6、 the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front c
7、over, an inside front cover, the EN title page, pages 2 to 14, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NOR
8、MEN 12255-16September 2005ICS 13.060.30English VersionWastewater treatment plants - Part 16: Physical (mechanical)filtrationStations dpuration - Partie 16: Filtration physique(mcanique)Klranlagen - Teil 16: AbwasserfiltrationThis European Standard was approved by CEN on 28 July 2005.CEN members are
9、bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the
10、Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status a
11、s the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain
12、, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Member
13、s.Ref. No. EN 12255-16:2005: EEN 12255-16:2005 (E) 2 Contents Page Foreword 3 1 Scope .5 2 Normative references .5 3 Terms and definitions.5 4 Requirements 5 4.1 General 5 4.2 Process types6 4.2.1 Granular media filters .6 4.2.2 Microstrainers and drum filters .6 5 Planning.6 6 Process design .7 6.1
14、 Design parameters7 6.2 Selection of filter media7 6.2.1 General 7 6.2.2 Granular media filters .8 6.2.3 Microstrainers and drum filters .8 6.3 Cleaning systems8 6.3.1 General 8 6.3.2 Granular media filters .9 6.3.3 Microstrainers and drum filters .9 6.4 Dimensions9 6.4.1 General 9 6.4.2 Granular me
15、dia filters .10 6.4.3 Microstrainers and drum filters .10 6.5 Flow distribution .10 6.5.1 General 10 6.5.2 Granular media filters .10 6.5.3 Microstrainers and drum filters .11 6.6 Construction principles11 6.6.1 General 11 6.6.2 Granular media filters .11 6.6.3 Microstrainers and drum filters .11 6.
16、7 Mechanical and electrical equipment12 6.7.1 General 12 6.7.2 Granular media filters .12 6.7.3 Microstrainers and drum filters .12 6.8 Performance monitoring 12 6.9 Additional considerations 13 6.9.1 Maintenance 13 6.9.2 Protection of the equipment.13 6.10 Hazard protection13 Bibliography.14 EN 122
17、55-16:2005 (E) 3 Foreword This European Standard (EN 12255-16:2005) has been prepared by Technical Committee CEN/TC 165 “waste water engineering”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical t
18、ext or by endorsement, at the latest by March 2006, and conflicting national standards shall be withdrawn at the latest by March 2006. It is the sixteenth part prepared by the Working Groups CEN/TC 165/WG 42 and 43 relating to the general requirements and processes for treatment plants for a total n
19、umber of inhabitants and population equivalents (PT) over 50. EN 12255 with the generic title “Wastewater treatment plants“ consists of the following Parts: Part 1: General construction principles Part 3: Preliminary treatment Part 4: Primary settlement Part 5: Lagooning processes Part 6: Activated
20、sludge process Part 7: Biological fixed-film reactors Part 8: Sludge treatment and storage Part 9: Odour control and ventilation Part 10: Safety principles Part 11: General data required Part 12: Control and automation Part 13: Chemical treatment Treatment of wastewater by precipitation/flocculation
21、 Part 14: Disinfection Part 15: Measurement of the oxygen transfer in clean water in aeration tanks of activated sludge plants Part 16: Physical (mechanical) filtration NOTE For requirements on pumping installations at wastewater treatment plants, provided initially as Part 2 “Pumping installations
22、for wastewater treatment plants“, see EN 752-6 “Drain and sewer systems outside buildings Part 6: Pumping installations. The parts EN 12255-1, EN 12255-3 to EN 12255-8 and EN 12255-10 and EN 12255-11 were implemented together as a European package (Resolution BT 152/1998). Differences in wastewater
23、treatment throughout Europe have led to a variety of systems being developed. This European Standard gives fundamental information about the systems; this European Standard has not attempted to specify all available systems. EN 12255-16:2005 (E) 4 Detailed information additional to that contained in
24、 this European Standard may be obtained by referring to the bibliography. The primary application is for wastewater treatment plants designed for the treatment of domestic and municipal wastewater. Physical filtration plant include gravity filters (static-bed or moving-bed types) and sieves (microst
25、rainers and drum filters). According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
26、 Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 12255-16:2005 (E) 5 1 Scope This European Standard specifies design principles and performance requirements for tertiary clarification (
27、receiving effluent from secondary treatment) by physical filtration plant at wastewater treatment plants serving more than 50 PT. 2 Normative references The following referenced documents are indispensable for the application of this European Standard. For dated references, only the edition cited ap
28、plies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 1085:1997, Wastewater treatment Vocabulary EN 122551, Wastewater treatment plants Part 1: General construction principles EN 1225510, Wastewater treatment plants Part 10: Safety princi
29、ples 3 Terms and definitions For the purposes of this European Standard, the terms and definitions given in EN 1085:1997 and the following apply. 3.1 granular media filter bed of filter media which is submerged in either an upflow or downflow of effluent to remove solids within the bed 3.2 drum filt
30、er or microstrainer cylindrical sieve or cloth filter which rotates about a horizontal axis and is partially-immersed in a horizontal flow of effluent to remove solids 4 Requirements 4.1 General Physical filtration processes can include the following: granular media filters; sieves such as microstra
31、iners and drum filters. Filter processes are used to remove fine suspended solids from treated wastewater by mechanical filtration. Where aeration is involved, it is normally limited to air scouring to remove solids accumulation trapped by filtration. Physical filters may also be designed to remove
32、phosphate. EN 12255-16:2005 (E) 6 4.2 Process types 4.2.1 Granular media filters 4.2.1.1 Static bed filter An upflow or downflow of effluent percolates rapidly through a bed of filter media trapping solids within the bed. For shallow bed and downflow filters, solids are predominantly captured at the
33、 surface. The rate of filtration is high causing a rapid accumulation of solids in the bed and a high rate of increase in headloss. At regular intervals a bed shall be taken out of service and washed using filtered effluent with or without air scour to remove accumulated solids. Washing can be affec
34、ted by either a pumped or siphonic upflow of filtered effluent across the entire bed or by a travelling bridge washing individual compartments. 4.2.1.2 Moving-bed filter (continuous operation) In this style of filter, an upflow or downflow of effluent passes continuously through a bed of mineral med
35、ia to remove solids. An air lift raises mineral media from the bottom of the bed for washing and returns cleaned media to the top of the bed, enabling continuous filtration. 4.2.2 Microstrainers and drum filters Microstrainers and drum filters are based on a sieve or cloth covered cylinder rotating
36、horizontally about the longitudinal axis. The cylinder is suspended in a tank to which the effluent to be filtered is supplied. Drum filters are partially or completely submerged in the effluent to be filtered, whilst a microstrainer cylinder is only immersed to about two thirds of its diameter. In
37、microstrainers the liquid flow is from inside to outside the cylinder. In drum filters the liquid flow is from the outside to inside the cylinder. For a microstrainer, backwash nozzles situated vertically above the rotating cylinder, direct effluent onto the upper cylinder surface and dislodge trapp
38、ed solids into a trough within the rotating cylinder. For a drum filter a backwash pump with nozzles situated laterally and close to the filter cloth surface induces flow of filtered effluent back through the cloth against the main flow of the wastewater. The flow of filtered effluent dislodges trap
39、ped solids which are then pumped away from the equipment. Drum filters generally do not rotate except when backwashing takes place. 5 Planning The choice of physical filtration process depends on the size of the treatment plant, space available, the type, quality, quantity and variability of effluen
40、t to be treated, the final quality of effluent required, and the frequency of maintenance that is required for the process. Physical filtration may be used to supplement efficient secondary solids separation. The following factors shall be considered in design: type and efficiency of secondary treat
41、ment and clarification processes; capacity and dimensions of the filtration plant; quality required for treated effluent; range and variation in hydraulic or suspended solids loads; prevention of dead zones and detrimental deposition in tanks or channels; establishment of multiple units or other tec
42、hnical means to ensure maintenance of required final effluent quality if one or more units are out of operation; EN 12255-16:2005 (E) 7 final destination of the liquors generated from washing; head loss to be minimised; measurement and control; media specification; tests to determine the required di
43、mensions of filter media or cloths. 6 Process design 6.1 Design parameters The following operational parameters shall be considered and values shall be selected which are appropriate for the required level of treatment: surface loading rate required (m3/m2x h); suspended solids load (kg/h); pore or
44、media size; maximum wash water requirement as a percentage of the treated flow rate; frequency of backwashing to maintain filtration rate; disposal route for backwash liquors; control of influent flows to the treatment process during washing; control of excessive instantaneous wash water flow rates.
45、 6.2 Selection of filter media 6.2.1 General Filter media should have an extensive surface area with narrow pores or channels designed to flocculate and trap suspended solids, and to allow effluent flow with minimum head loss. The filter media shall be capable of cleansing through some form of backw
46、ashing or scouring. Influents to the filters include varying proportions of colloidal to non-colloidal suspended solids. Microstrainers can be less suited to removal of colloidal material than other processes. Filterability tests should be carried out and the required effluent quality shall be consi
47、dered before making a choice of process for physical filtration. The following factors shall also be considered in choice of media: design life; quality of influent; requirements for replacement; ease of replacement; EN 12255-16:2005 (E) 8 durability to withstand weathering and exposure to sunlight
48、where applicable; durability to withstand corrosion and chemical attack; non-biodegradability; ease of cleaning by backwashing; resistance to abrasion during backwashing; pore sizes. 6.2.2 Granular media filters Filter media can be made from the following materials: graded mineral; plastics of regul
49、ar size and shape and randomly arranged. The filter media should have a spherical shape and narrow size distribution to form a bed with a high porosity, and smooth surface to enable efficient washing. The particle size distribution, shape for the materials constituting the bed and also the depth of the bed shall be selected taking account of the effluent to be treated and the desired filtrate quality requirements. For filters which contain shallow beds (0,3 m to 0,5 m de
