Section 2 by Sk6813Vm

VIEWS: 0 PAGES: 8

									                                                      Page 1 of 8
                                           Section 2 Chapter 17e




     Chapter 17e
Sewage treatment works:
     compliance




         June return reporting requirements and definitions manual
                                           2004/1.2 – 8 June 2004
Page 2 of 8
Section 2 Chapter 17e


Chapter 17e
Sewage treatment works: compliance
Guidance to companies
The purpose of this table is to collect information on works compliance by treatment type and size. The
information will be used as an explanatory factor in Ofwat's revision of sewage treatment works (STW)
models.

The compliance figures reported in the table must be an unweighted average of the compliance figures
for the STW in each of the various size/treatment type categories. The compliance figures used must be
those determined by the Environment Agency and not a company's own assessment of compliance.

Companies must calculate the percentage compliance figure for individual sewage treatment works as:

STW compliance = 1- number of failures for sanitary determinands x 100%
                    total number of sanitary determinands tested

The STW size banding used is the same as described for table 17c and in the general guidance.

Guidance to Reporters
Reporters must ensure that the figures used agree with those determined by the EA. If the figures are not
consistent with those reported by the EA, the Reporter must comment and explain any changes.

Reporters must comment on whether or not companies have followed the above guidance on calculating
compliance figures.




June return reporting requirements and definitions manual
2004/1.2 – 8 June 2004
                                                                                           Page 3 of 8
                                                                                Section 2 Chapter 17e

Column definitions
The definitions for the columns are as defined in the common definitions in Chapter 17.1.

Line definitions

   1      Compliance by STWs in size band 1                                            %(1dp)

 Full line title:         Compliance by sewage treatment works in size band 1.

 Primary purpose:         Informing relative performance and efficiency assessments.

 Definition:              The average percentage of compliance with discharge consents for STWs of
                          size band 1 ( <= 15kg BOD5/day) for each treatment category. This should be
                          calculated as the unweighted mean for works in each particular treatment
                          category. The convention outlined under the common definitions should be
                          used to calculate STW size. Sea outfalls should include those discharging
                          untreated sewage and sewage subject to preliminary treatment in the relevant
                          column.

                          The figures reported must be the compliance figures determined by the
                          Environment Agency, not as interpreted by the company.

 Processing rules:        Input field

 Responsibility:          Comparative Efficiency Team

 Previous references: STWE001 – STWE010



   2      Compliance by STWs in size band 2                                            %(1dp)

 Full line title:         Compliance by sewage treatment works in size band 2.

 Primary purpose:         Informing relative performance and efficiency assessments.

 Definition:              The average percentage of compliance with discharge consents for STWs of
                          size band 2 (15 - 30kg BOD5/day) for each treatment category. This should be
                          calculated as the unweighted mean for works in each particular treatment
                          category. The convention outlined under the common definitions should be
                          used to calculate STW size. Sea outfalls should include those discharging
                          untreated sewage and sewage subject to preliminary treatment in the relevant
                          column.

                          The figures reported must be the compliance figures determined by the
                          Environment Agency, not as interpreted by the company.

 Processing rules:        Input field

 Responsibility:          Comparative Efficiency Team

 Previous references: STWE015 – STWE 024.




                                            June return reporting requirements and definitions manual
                                                                              2004/1.2 – 8 June 2004
Page 4 of 8
Section 2 Chapter 17e


   3      Compliance by STWs in size band 3                                           %(1dp)

 Full line title:        Compliance by sewage treatment works in size band 3.

 Primary purpose:        Informing relative performance and efficiency assessments.

 Definition:             The average percentage of compliance with discharge consents for STWs of
                         size band 3 ( 30 - 120kg BOD5/day) for each treatment category. This should
                         be calculated as the unweighted mean for works in each particular treatment
                         category. The convention outlined under the common definitions should be
                         used to calculate STW size. Sea outfalls should include those discharging
                         untreated sewage and sewage subject to preliminary treatment in the relevant
                         column.

                         The figures reported must be the compliance figures determined by the
                         Environment Agency, not as interpreted by the company.

 Processing rules:       Input field

 Responsibility:         Comparative Efficiency Team

 Previous references: STWE029 – STWE038



   4      Compliance by STWs in size band 4                                           %(1dp)

 Full line title:        Compliance by sewage treatment works in size band 4.

 Primary purpose:        Informing relative performance and efficiency assessments.

 Definition:             The average percentage of compliance with discharge consents for STWs of
                         size band 4 (120 - 600kg BOD5/day) for each treatment category. This should
                         be calculated as the unweighted mean for works in each particular treatment
                         category. The convention outlined under the common definitions should be
                         used to calculate STW size. Sea outfalls should include those discharging
                         untreated sewage and sewage subject to preliminary treatment in the relevant
                         column.

                         The figures reported must be the compliance figures determined by the
                         Environment Agency, not as interpreted by the company.

 Processing rules:       Input field

 Responsibility:         Comparative Efficiency Team

 Previous references: STWE043 – STWE052




June return reporting requirements and definitions manual
2004/1.2 – 8 June 2004
                                                                                           Page 5 of 8
                                                                                Section 2 Chapter 17e


  5      Compliance by STWs in size band 5                                            %(1dp)

Full line title:       Compliance by sewage treatment works in size band 5.

Primary purpose:       Informing relative performance and efficiency assessments.

Definition:            The average percentage of compliance with discharge consents for STWs of
                       size band 5 (600kg - 1500kg BOD5/day) for each treatment category. This
                       should be calculated as the unweighted mean for works in each particular
                       treatment category. The convention outlined under the common definitions
                       should be used to calculate STW size. Sea outfalls should include those
                       discharging untreated sewage and sewage subject to preliminary treatment in
                       the relevant column.

                       The figures reported must be the compliance figures determined by the
                       Environment Agency, not as interpreted by the company.

Processing rules:      Input field

Responsibility:        Comparative Efficiency Team

Previous references: STWE057 – STWE066



  6      Compliance by STWs in size band 6                                            %(1dp)

Full line title:       Compliance by sewage treatment works in size band 6.

Primary purpose:       Informing relative performance and efficiency assessments.

Definition:            The average percentage of compliance with discharge consents for STWs of
                       size band 6 (>1500kg BOD5/day) for each treatment category. This should be
                       calculated as the unweighted mean for works in each particular treatment
                       category. The convention outlined under the common definitions should be
                       used to calculate STW size. Sea outfalls should include those discharging
                       untreated sewage and sewage subject to preliminary treatment in the relevant
                       column.

                       The figures reported must be the compliance figures determined by the
                       Environment Agency, not as interpreted by the company.

                       Where a works load is split into two treatment streams in Table 17b, the
                       works should be reported consistently with the classification in Table 17b, line
                       27.

Processing rules:      Input field

Responsibility:        Comparative Efficiency Team

Previous references: STWE071 – STWE080




                                          June return reporting requirements and definitions manual
                                                                            2004/1.2 – 8 June 2004
Page 6 of 8
Section 2 Chapter 17e


   7      Average compliance by STWs - all sizes                                      %(1dp)

 Full line title:        Average compliance by sewage treatment works of all sizes for each
                         treatment category.

 Primary purpose:        Informing relative performance and efficiency assessments.

 Definition:             The total average percentage of compliance with discharge consents for all
                         STWs in each treatment category. This should be calculated as the
                         unweighted mean of percentage compliance for all sizes of works of each
                         particular treatment type.

                         Sea outfalls should include those discharging untreated sewage and sewage
                         subject to preliminary treatment in the relevant column.

                         The figures reported must be the compliance figures determined by the
                         Environment Agency, not as interpreted by the company.

 Processing rules:       Input field

 Responsibility:         Comparative Efficiency Team

 Previous references: STWE085 – STWE094



   8      Compliance by small STW w. NH3 consents (5 - 10mg/l)                        %(1dp)

 Full line title:        Overall percentage compliance with consents for small sewage treatment
                         works with ammonia consents.

 Primary purpose:        Informing relative performance and efficiency assessments.

 Definition              The average percentage of compliance with discharge consents for all types
                         of small STWs (receiving <=1500kg by BOD5/day load) with ammonia (NH3)
                         consents which are less than (or equal to) 10mg/l but greater than 5 mg/l.
                         This should be calculated as the unweighted mean of percentage compliance
                         for all sizes of works of each particular treatment type.

                         The figures reported must be the compliance figures determined by the
                         Environment Agency, not as interpreted by the company.

                         Note that small STWs with ammonia consents must be included in the figures
                         above (lines 1-7) as well as in lines 8 and 9.

 Processing rules:       Input field

 Responsibility:         Comparative Efficiency Team

 Previous references: STWE099




June return reporting requirements and definitions manual
2004/1.2 – 8 June 2004
                                                                                        Page 7 of 8
                                                                             Section 2 Chapter 17e



  9      Compliance by small STW w. NH3 consents (< = 5mg/l)                        %(1dp)

Full line title:       Overall percentage compliance with consents for small sewage treatment
                       works with ammonia consents.

Primary purpose:       Informing relative performance and efficiency assessments.

Definition:            The average percentage of compliance with discharge consents for all types
                       of small STWs (receiving <=1500kg by BOD5/day load) with ammonia
                       (NH3)consents which are less than (or equal to) 5 mg/l. This should be
                       calculated as the unweighted mean of percentage compliance for all sizes of
                       works of each particular treatment type.

                       The figures reported must be the compliance figures determined by the
                       Environment Agency, not as interpreted by the company.

                       Note that small STWs with ammonia consents must be included in the figures
                       above (lines 1-7) as well as in lines 8 and 9.

Processing rules:      Input field

Responsibility:        Comparative Efficiency Team

Previous references: STWE113




                                         June return reporting requirements and definitions manual
                                                                           2004/1.2 – 8 June 2004
Page 8 of 8
Section 2 Chapter 17e

CHANGE CONTROL SHEET
CHAPTER 17e

  Issue date                                    Description of change


 31/1/97


 4/4/97           1.     Lines 1 - 9: individual line definitions incorporated
                  2.     Line titles in table picture revised
                  3.     Unit of measure corrected to %.


 16/5/97          1.     Additional guidance on derivation of compliance figures.
                  2.     Additional guidance for Reporters.


 27/2/98          1.     Change in guidance to method of calculating STW compliance
 First issue of   2.     Prior year JR98 references revised.
 Enhanced
 JR98 Manual


 2/7/2001         1.     No changes to this Chapter.


 6/8/2001         1.     Guidance to Line 6 revised to take account of changes in Table 17b.


 03/5/2002        1.     No changes to this Chapter.


 5/6/2003         1.     Textual changes to guidance.


 2004/1.0         1.     Chapter 17e brought into June return.
 11/12/03         2.     There are no changes to this Chapter in version 1.0.

 2004/1.1         1.     There are no changes in this Chapter for issue 1.1.
 11/03/04

 2004/1.2         1.     There are no changes in this Chapter for issue 1.2.
 08/06/04




June return reporting requirements and definitions manual
2004/1.2 – 8 June 2004

								
To top