E1.1.1 The sewage flows to be generated from the Preliminary Preferred Development Option are estimated in the Table E.1. This assessment is applicable to the Preferred Development Option, as the Preliminary Preferred Development Option is slightly more intensive than the Preferred Development Option.

Table E.1 Estimated Sewage Flows

E1.1.3 The Study Area is located at the upstream end of the existing sewerage network for Ma On Shan New Town which has not been designed to cater for the development.

E1.1.4 In 2000, TDD commissioned a Feasibility Study Assignment on Additional Sewerage and Sewage Treatment Works in Sha Tin and Ma On Shan. The study recommended:

(i) to reconstruct the Ma On Shan Area 108 Sewage Pumping Station (by May 2007 tentatively);

(ii) additional new sewers to be laid in the similar alignment to the existing trunk sewers in Ma On Shan district;

(iii) installation of one additional pump at Ma On Shan Main Pumping Station; and

(iv) minimisation of transient effect on Sha Tin Sewage Treatment Works by modification of the existing fixed speed sewage pumps to a variable speed pump.

E1.1.5 The above works have taken into account the proposed population of the Base Scheme considered in Technical Report No. TR1 & 2 for this Study. Since the population quantum for the Preferred Development Option is significantly less than that for the Base Scheme, review of the findings in the above assignment is not required.

E1.1.6 The Stage III extension to Sha Tin Sewage Treatment Works is under construction and will be completed by 2007. Similar to the situation explained in the preceding paragraph, the treatment works upon expansion will have sufficient capacity to serve the Preferred Development Option.

Sewerage Works within Study Area

E1.1.7 Based on the above, only gravity sewers would need to be laid to Area 108 Sewage Pumping Station (SPS) as local improvement works to serve the proposed development to the north of Sai Sha Road. A short connection would be required for the Wu Kai Sha Station development which is located to the south of the road and next to Area 108 SPS.

E1.1.8 A network of gravity sewers is proposed beneath roads within the development to connect to Area 108 Pumping Station, as conceptually shown on Figure E.2. Two gravity sewers are proposed to run from the north of Whitehead along Roads L1 & L2, Road D1(W) and Road D1(E) to collect sewerage generated from proposed development. A stretch of footpath along Sai Sha Road adjacent to Lok Wo Sha development will be widened to accommodate the proposed sewer by constructing a retaining wall along the existing slope. The sewage collected will be conveyed to Ma On Shan Area 108 Sewage Pumping Station for discharge via the Ma On Shan sewerage network to the Sha Tin STW.