1、BRITISH STANDARD BS EN 12255-5:1999 Incorporating Corrigendum No.1 Wastewater treatment plants Part 5: Lagooning processes The European Standard EN 12255-5:1999 has the status of a British Standard ICS 13.060.30 BS EN 12255-5:1999 This British Standard, was published under the authority of the Stand
2、ards Policy and Strategy Committee on 15 December 1999 BSI 27 July 2004 ISBN 0 580 35056 8 National foreword This British Standard is the official English language version of EN 12255-5:1999. The UK participation in its preparation was entrusted by Technical Committee B/505, Wastewater engineering,
3、to Subcommittee B/505/40, Wastewater treatment plants, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. This standard is published with a national annex, which provides further information for the UK user on polish
4、ing ponds. Cross-references The 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 C
5、atalogue 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 understa
6、nd the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a
7、 front cover, an inside front cover, the EN title page, pages 2 to 9 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments 15266 Corrigendum No.1 27 July 2004 Addition of national
8、annex(8523($167$1$5 1250(8523e(11( (8523b,6 has a warm temperature and generates density gradients within the lagoon. NA.2 Polishing ponds Table NA.1 Typical surface loading rates for polishing ponds Treatment required Type of process Number of lagoons Surface loading rate aRetention time m 3 /m 2 h
9、 d Clarification Low rate 2 or more in series 0.02 to 0.03 2 bPhosphate removal Low rate 2 in series 0.004 to 0.006 10 ca Based on typical depth of 1 to 1.5 m. bTo minimize algal growth which increase effluent suspended solids. cTo promote algal growth which assimilates phosphate and must be subsequ
10、ently removed. National bibliography Standards publications BS 6297, Code of practice for design and installation of small sewage and treatment works and cesspools. Other publications 1 The Chartered Institution of Water and Environmental Management. Handbook of UK Wastewater Practice, Tertiary Treatment (second edition). CIWEM: 1994. Page9 BSEN122555:1999
