LCQ13: Enhancing the odour control of the West Kowloon Transfer Station and sewage treatment works

     Following is a question by Dr the Hon Priscilla Leung and a written reply by the Secretary for the Environment, Mr Wong Kam-sing, in the Legislative Council today (April 20):


     Since January 6 this year, the South East New Territories Landfill located in Tseung Kwan O has been designated to receive only construction waste, and the domestic, commercial and industrial waste that the landfill used to receive has to be diverted to other refuse transfer stations (transfer stations) and landfills (new measure). Quite a number of the residents in Mei Foo and the neighbouring residential areas (including the West Kowloon Four-Little-Dragon Estates and Hoi Lai Estate) have relayed to me that as refuse collection vehicles travel to and from the West Kowloon Refuse Transfer Station more frequently under the new measure, and the Stonecutters Island Sewage Treatment Works has increased the volume of sewage it handles upon completion of its extension works, the odour problem in the district has worsened. The residents often have to keep their windows closed and switch on air-conditioners to insulate themselves from the odour. They have also pointed out that as the transfer station is already overloaded, quite a number of refuse collection vehicles need to queue up for a long time to enter that transfer station every day, emitting odour and blocking the traffic during such process. In this connection, will the Government inform this Council:

(1) whether it has reviewed the impacts of the new measure on the loading of the various transfer stations and on the residents near the transfer stations; if it has, of the details; whether it has assessed if the implementation of the new measure is fair to the residents near the transfer stations, and whether it has formulated any long-term plan to improve the waste diversion; if it has, of the details; if not, the reasons for that;

(2) of the number of complaints about the odour problem that the authorities received from the residents of the aforesaid district and the follow-up actions taken in each of the past five years; whether they have conducted any study on the relationship between the odour problem in the district and the transfer station; if they have, of the details; if not, the reasons for that;

(3) given that while the new facilities of the Stonecutters Island Sewage Treatment Works were commissioned at the end of last year to enable the sewage treatment works to treat more sewage, the residents nearby are complaining about the worsening of the odour problem, whether the Government has reviewed the management and effectiveness of the existing deodourization facilities at the sewage treatment works; if it has, of the details; if not, the reasons for that; and

(4) given that the odour in the aforesaid district partly comes from the food waste in the domestic waste, whether the authorities have any measures in place to encourage members of the public to further reduce food waste?



     Our reply to the question raised by Dr the Hon Priscilla Leung is as follows:

(1) The Environmental Protection Department (EPD) implemented a Waste Diversion Plan (WDP) to ensure that, after the designating of South East New Territories (SENT) Landfill at Tseung Kwan O to receive only construction waste, other waste that could not be accepted by the SENT Landfill would be properly handled by the existing waste collection network. Under the WDP, the EPD has redistributed the amount of waste received by various refuse transfer stations (RTSs) and landfills so as to maximise the utilisation of those waste management facilities with spare capacity and minimise the environmental impact on the community due to waste diversion.  To facilitate the above arrangement, the Food and Environmental Hygiene Department has adjusted some of its refuse collection routes by which waste is diverted away from the areas affected by the waste diversion to other RTSs or landfills as assigned by the EPD, so as to make available sufficient handling capacity for the waste diverted from the SENT Landfill.  The EPD has also opened up the Shatin Transfer Station and aligned the fee for use of refuse transfer service in urban areas to the same level so as to encourage private waste collectors to better utilise the waste management facilities in various districts.  With the SENT Landfill receiving only construction waste since January 6 this year, the operation of various RTSs has been smooth.  As for the West Kowloon Transfer Station (WKTS), there is no significant difference in terms of the amount and type of waste received before and after the implementation of the WDP, details are set out in Annex 1.

     Furthermore, as the improvement and refurbishment works completed earlier on have enhanced the operational efficiency of the WKTS, the traffic flow inside the station for waste disposal is smoother, the time required for handling waste has been shortened, the queuing situation has been improved and the efficiency on odour control has been enhanced. At present vehicles entering the WKTS can normally dispose of waste within 30 minutes, which has significantly improved when comparing with the time required for waste disposal during peak hours in the past. No plant failure or operation incident has occurred which would otherwise have led to long queuing at the WKTS.

(2) The figures on complaints about the odour problem that the EPD received from residents of the aforesaid areas over the past five years are set out in Annex 2.

     The EPD has carried out follow up investigation for every complaint received and conducted regular inspections on the WKTS and Stonecutters Island Sewage Treatment Works (SCISTW).  During these inspections over the past five years, the EPD officers found that the operation of both facilities and their odour mitigation measures was normal.

     On the other hand, the EPD is committed to enhancing the odour control and environmental performance of the WKTS.  It has also set out stringent contractual requirements for the contractor of the WKTS with respect to its operational and environmental management, with a view to ensuring that its operation will not cause any environmental nuisance to the neighbourhood.  For monitoring of odour, three inspections are carried out by the station staff every day and another three by an independent consultant every week.  The odour management of the WKTS has been found to be in compliance with the contractual requirements over the past six months (and also since the WDP was implemented).  In December 2012, several improvement works were commenced and measures implemented for the WKTS.  They included the enhancement of air scrubbing devices and the installation of air curtains to further reduce odour emission; the improvement of the vehicle washing facilities to ensure cleanliness of refuse collection vehicles leaving the station; and the installation of additional mobile deodourisers in the WKTS.  These improvement works were completed in December 2014.  To ensure compliance with environmental performance requirements, the contractor of the WKTS has increased the frequency of cleansing the station, nearby roads and the containers used for waste transfer.  The contractor has also increased the frequency of odour monitoring.  In January 2014 and July 2015, the Environment and Hygiene Committee of the Sham Shui Po District Council conducted two site visits to the WKTS to inspect its operation.  Members of the Committee witnessed the improvement in odour management within the station.  The EPD will continue to closely monitor the operation and environmental performance of the WKTS to prevent it from causing any environmental nuisance to the neighbourhood.

(3) The Drainage Services Department (DSD) takes the environmental management of the SCISTW very seriously and strives to ensure that all the treatment processes operate properly.  Currently, all the sewage and sludge treatment processes of the SCISTW are conducted in an enclosed environment.  The plant workers also strictly comply with the established odour control measures, which include:

(a) application of chemicals, such as ferric chloride and other deodourising agents, to curb odour emission from sewage;

(b) covering up potential odour emission sources, such as channels and sewage treatment facilities;

(c) installation of odour abatement units, such as activated carbon systems, chemical scrubbers and biofilters, at appropriate locations; and

(d) regular cleansing of the sewer system.

     The Harbour Area Treatment Scheme Stage 2A has been commissioned since late 2015 to upgrade and strengthen the odour control measures for the SCISTW.  Indeed, the DSD has significantly curbed potential odour emission by covering up all sedimentation tanks in the SCISTW since September 2012.  In addition to closely monitoring the plant operation, the DSD has also engaged an independent accredited laboratory to regularly monitor the level of ambient hydrogen sulphide within the plant.  According to its air quality monitoring records, the average monthly level of ambient hydrogen sulphide at the plant perimeters remained below 0.2 ppm for the past five years.  This odour level would not cause nuisance to the odour sensitive areas in the neighbourhood.

     The DSD will closely monitor the performance of the system and carry out regular inspections and appropriate maintenance works.  To protect the surrounding environment, the DSD will also monitor the plant operation and efficacy of its odour abatement facilities to ensure their proper operation.

(4) The Environment Bureau unveiled the "A Food Waste and Yard Waste Plan 2014-2022" in February 2014 to set out four main strategies as the backbone to tackle the food waste challenge, namely reduction at source, reuse and donation, recyclable collection, and turning food waste into energy, with a target of reducing food waste disposal to landfills by 40 per cent in 2022.  To mobilise our community to avoid and reduce food waste at source, the EPD has launched various education and publicity programmes in the past few years, such as the Food Wise Hong Kong Campaign, Food Waste Recycling Partnership Scheme and Food Waste Recycling Projects in Housing Estates.  The EPD, in collaboration with the commercial and industrial sectors, implemented the Food Waste Recycling Partnership Scheme in June 2010 to assist with the training of managerial and frontline staff of participating organisations on good food waste management practices and rules.  The Scheme aims to encourage the concerned trades (such as food factories) to avoid and reduce food waste at source, and perform separation at source and recycling for unavoidable food waste.  Launched in May 2013, the Food Wise Hong Kong Campaign encourages behavioural changes in the community through various programmes that promote food waste reduction at source.  Good practices of food waste reduction have also been drawn up for the trades concerned (such as the catering sector) to facilitate their reduction of food waste.  In November 2015, the EPD further launched the Food Wise Eateries Scheme to encourage eateries in the catering and hotel industries to offer food portioning options and take food waste reduction measures, thereby collaborating with their customers to reduce food waste at source.  As regards to waste treatment, the first phase of the organic waste treatment facilities (OWTF) is under construction.  It is expected that the OWTF will commence operation in 2017 and about 200 tonnes of food waste can then be treated and turned into energy per day.

Ends/Wednesday, April 20, 2016
Issued at HKT 16:44