LCQ7: Odour problem at Tsuen Wan waterfront

     Following is a question by Dr Hon Kwok Ka-ki and a written reply by the Secretary for the Environment, Mr Wong Kam-sing, in the Legislative Council today (October 23):

Question:

     Some residents of Tsuen Wan West have relayed that the seawater odour problem of Rambler Channel off the Tsuen Wan waterfront has been causing distress to them for many years. The Environmental Protection Department (EPD) has indicated that polluted water and matters have been discharged into the stormwater drainage system of Tsuen Wan District, and the organic matters therein have deposited and accumulated inside the culverts and then decayed, thus generating the odour. The Review of West Kowloon and Tsuen Wan Sewerage Master Plans, which was completed by the EPD in 2010, identified in Tsuen Wan District three and 49 cases of misconnection of foul water pipes to stormwater drains (foul water pipe misconnection cases) by street-level shops and buildings respectively. In this connection, will the Government inform this Council:

(1) of the respective numbers of foul water pipe misconnection cases which have been (i) uncovered, (ii) followed up and (iii) rectified by the authorities since 2010;

(2) given that the Drainage Services Department is constructing and plans to construct a total of 12 dry weather flow interceptors to reduce pollution to the water in the coastal area of Tsuen Wan Bay and Rambler Channel, but such interceptors will be able to remove only about 70 per cent of the total pollution loading from the stormwater drainage system, whether the authorities will consider providing financial assistance to the owners' corporations in need, so as to expedite the rectification of foul water pipe misconnections in buildings; if so, of the details; if not, how the authorities will encourage property owners and their owners' corporations to solve the problem; and

(3) whether the EPD will collaborate with other government departments to enhance monitoring and testing work, so as to identify more street-level shops and buildings which have misconnected foul water pipes; if so, of the details and the timetable; if not, how the authorities thoroughly solve the odour problem at the Tsuen Wan waterfront?

Reply:

President,

     In an effort to improve the water quality of Victoria Harbour, the Government has been progressively implementing the Harbour Area Treatment Scheme (HATS). Upon full commissioning of the HATS Stage 2A in December 2015, all sewage generated in areas around Victoria Harbour, including Kowloon, Tsuen Wan and most parts of Hong Kong Island has been intercepted and diverted to the Stonecutters Island Sewage Treatment Works for centralised treatment. As a result, the overall water quality in the harbour has significantly improved. However, there are still residual polluting discharges entering certain coastal waters of Victoria Harbour, causing some degree of odour problems. The Environmental Protection Department (EPD), in collaboration with other relevant departments, has been implementing a series of measures to control near-shore pollution problems at source.

     The reply to the question raised by Dr Hon Kwok Ka-ki is as follows:
 
(1) The Review of West Kowloon and Tsuen Wan Sewerage Master Plans, which was completed by the EPD in 2010, identified 52 cases of sewage being discharged into storm drains in Tsuen Wan District. Among these cases, 38 have already been rectified, while the remaining 14 are being handled by the Buildings Department (BD). These remaining cases all involve communal pipe misconnections within buildings in old districts. About half of these buildings do not have owners' corporations (OCs) formed and hence more time is required in co-ordinating with owners and residents to solve the misconnection problems. Apart from that, the EPD had carried out more than 1 300 effluent discharge inspections in Tsuen Wan District from 2010 to September 2019 and revealed 15 cases of sewer pipe misconnection. Among these cases, 14 have been rectified. The remaining case is being followed up by a restaurant's owner and the rectification work is expected to be completed by the end of this year.

(2) At present, the BD, the Urban Renewal Authority (URA) and the Hong Kong Housing Society (HKHS) are implementing a number of financial assistance schemes to assist eligible building owners in carrying out building repair and maintenance, including the rectification of defective drainage within buildings. Details are set out as follows:
 

     In addition, to further safeguard public safety, the Government plans to launch the Operation Building Bright 2.0 at a cost of $3 billion to provide technical and financial assistance to eligible building owners to carry out inspection and repair works under the Mandatory Building Inspection Scheme, including the rectification of defective drainage within buildings.

(3) The EPD will continue to carry out pollution source investigation in Tsuen Wan District and trace the effluent discharge routing in each case to confirm the pollution source(s). If there is sufficient evidence, the EPD shall instigate prosecution against the suspected illegal discharger(s). When an expedient connection within buildings is identified during investigation, the case will be referred to the BD for follow-up under the Buildings Ordinance. If there is contravention of the Buildings Ordinance, the BD will supervise the duty holder to rectify the expedient connection.

     Sewage pipe misconnection is only one of the sources that causes residual polluting discharges entering certain coastal waters of Victoria Harbour through the stormwater drainage system. The EPD is carrying out a consultancy study on further enhancement of the near-shore water quality and the general environment of Victoria Harbour for developing a comprehensive plan to thoroughly solve the odour problems caused by residual polluting discharges entering certain coastal waters of Victoria Harbour. Apart from rectifying problems of sewage pipe misconnection, the study also reviews measures of enhancing collaboration between departments, raising public awareness on reducing discharge of pollutants to stormwater drains at source, as well as implementing engineering solutions such as provision of newly designed dry weather flow interceptors near the stormwater outfalls or at other strategic locations. The consultants will submit the complete study report within this year. While the study is yet to be completed, the Government is gradually implementing some pollution control works including the modification and construction of dry weather flow interceptors on both sides of Victoria Harbour, as well as systematic investigation and rehabilitation of ageing sewers with high risks of structural failure to alleviate leakage-induced odour problem across the territory. In addition, the Government is collaborating with academic institutions to investigate the application of "odour-control hydrogel" to inhibit odorous gas emission in the drainage system.

Note: Since July 1, 2015, the URA has taken over all the rehabilitation scheme areas previously managed by the HKHS under the three financial assistance schemes and provides a territory-wide service under the schemes. In other words, the HKHS has stopped accepting new applications under the three schemes since then but continues to process and follow up on applications received on or before June 30, 2015.