ENG-2004 — Page 307

Land, Public Works and Utilities | 257

The department also provides technical support to the Home Affairs Bureau and the Marine Department in assessing applications for fireworks displays.

Fill Supply and Mud Disposal

The Marine Fill Committee (MFC) is responsible for identifying and managing the supply of marine fill resources for development projects, and for managing disposal facilities for dredged and excavated sediment. The Public Fill Committee (PFC) has the duty to manage construction and demolition (C&D) materials and utilisation of land- based fill reserves. Both committees are responsible to the Secretary for the Environment, Transport and Works.

About 20.5 million tonnes of C&D materials were generated by local construction activities in 2004. Of this, about 18.1 million tonnes of inert materials were re-used as fill in projects such as Penny's Bay and Tai O developments, or stockpiled at the fill banks in Tuen Mun Area 38 and Tseung Kwan O Area 137.

The PFC explores ways to minimise the generation of C&D materials and reduce their disposal at landfills. Public construction works are required to adopt waste. management plans that reduce the generation of C&D materials at source. The temporary recycling facility at Tuen Mun Area 38 recycles suitable C&D materials into aggregates for re-use. In 2004, the recycling facility produced about 210 000 tonnes of recycled aggregates for use in government projects.

The MFC maintains a Fill Management Database on fill requirements, mud disposal and surplus excavated materials from major public and private projects. Its purpose is to help the construction industry coordinate sources of fill materials and make the best use of surplus materials. All project data is available at the CEDD's home page.

The department manages mud disposal facilities. In 2004, about 2.97 million cubic metres of uncontaminated mud and 1.55 million cubic metres of contaminated mud were generated from various works projects and maintenance works on navigational channels in the harbour. Uncontaminated mud was disposed of at open sea floor disposal grounds or exhausted marine sand borrow pits. Contaminated mud was placed in specially selected and closely monitored exhausted sand borrow pits, which were then capped with clean mud on completion of filling to isolate the contaminants from the environment. The use of exhausted sand borrow pits for mud disposal is preferred as it has the dual benefits of providing much needed disposal capacity and restoring the seabed to its natural profile and state.

In connection with the management of Hong Kong's fill resources and mud disposal capacity, the department, on behalf of the MFC, continues to undertake a series of geotechnical, environmental and ecological studies and monitoring to examine the effect of the dredging and disposal activities, and to investigate possible ways to avoid or minimise the impact on the marine environment.