Project Background

Tai Po Sewage Treatment Works (TPSTW) is located within the Tai Po Industrial Estate. It consists of the Stage I/II Works and the Stage IV works which are operated independently for some treatment process and otherwise for the others. The project TPSTW Stage 5 aims to upgrade the existing TPSTW to provide additional sewage treatment capacity from the present design flow of 88,000 m3/day to 120,000 m3/day to meet the demands of both the existing and future developments. The project TPSTW Stage 5 consists of two phases (i.e. Phase 1 and Phase 2 which, in turn, is implemented under Phase 2A and Phase 2B). The design capacities of Phase 1 and Phase 2 works are 100,000 m3/day and 120,000 m3/day, respectively.

Pursuant to the Environmental Impact Assessment Ordinance, the Phase 1 and Phase 2 works are "Designated Projects". An Environmental Impact Assessment was completed in 2004 with an Environmental Permit No. EP-202/2004 for Phase 1 works and an Environmental Permit No. EP-265/2007 for Phase 2 works issued afterwards. The EPs stipulates that an Environmental Monitoring and Audit (EM&A) programme is required to ensure the mitigation measures recommended in the Final Environmental Impact Assessment Report and the Final Environmental Monitoring and Auditing Manual, are implemented during the construction and operation of the Works.

* During the Environmental Impact Assessment stage, the projected design flow of the Phase 2 works was 130,000 m3/day. Based on the latest available planning data, the design capacity of the Phase 2 works has been reviewed to 120,000 m3/day.

Phase 1 Works

The project TPSTW Stage 5 Phase 1 aims to upgrade the existing TPSTW to provide additional treatment capacity to meet the demands of both the existing and future developments, and to meet the revised discharge licence requirements which will come into effect once the Project has been completed. The scope of the Phase 1 Works includes the expansion of and modifications to the existing TPSTW to increase the total plant design capacity from the present daily average dry weather flow of 88,000 m3/day to 100,000 m3/day. Key elements of the Project include:

• expansion of and modifications to the existing inlet works and preliminary treatment facilities;
• modifications to four existing bioreactors;
• construction of two final clarifiers and modification of six existing ones;
• additional sludge treatment facilities;
• construction of a filtrate treatment plant; and
• ancillary works to the existing treatment facilities.

Parties involved in the Phase 1 Works include :

Phase 2A Works

The project TPSTW Stage 5 Phase 2A forms part of the Phase 2 Works aims to upgrade the existing TPSTW to provide disinfection in TPSTW to meet the revised discharge licence requirements which will come into effect once the Project has been completed. The scope of the Phase 2A Works includes the provision of disinfection and ancillary facilities in TPSTW for its future extended plant design capacity of 120,000 m3/day. Key elements of the Phasthe provision of disinfection and ancillary facilities in TPSTW for its future extended plant design capacity of 120,000 m3/day. Key elements of the Phase 2A Works include:

(a) provision of ultraviolet (UV) disinfection facilities; and
(b) ancillary works including power supply systems, control systems, pipeworks, building services installations, fire services installations, lifting appliances and road works.

Parties involved in the Phase 2A Works include :