Environmental Challenges and Continuous Improvement

In 2004, we continued to face with the challenges of increasing volume of sewage to our sewage treatment works in which some have already been overloaded, and we have committed to improve our service delivery to meet the ever higher demand of the public on environmental quality. We took a two-pronged approach of maintaining a lively dialogue with the stakeholders to understand their concerns and explain our work, and exploring the latest proven technology to address the specific local environmental issues. A few examples of how we addressed the issues are given below.

Overloading of Sewage Treatment Works


We tackled the problem of sewage overloading by a long term solution of extending the capacity of our sewage treatment works.  In the interim, we modified the treatment processes and made extra effort to monitor the processes to achieve the effluent quality standards.  In 2004, the Stage 3 Phase 1 of the Shatin Sewage Treatment Works was commissioned successfully and the treatment capacity was increased from 148,000 to 216,000 m3/day. The treatment capacity will further be increased to 318,000 m3/day upon the successful commissioning of the Phase 2 of the project in 2005. The extension of the Tai Po Sewage Treatment Works and Shek Wu Hui Sewage Treatment Works were in satisfactory progress.

On process modification, we have been upgrading the Siu Ho Wan Treatment Works to Chemically Enhanced Primary Treatment with UV disinfection to remove BOD and disinfect the effluent, modifying two primary sedimentation tanks at Shek Wu Hui Sewage Treatment Works to Sequencing Batch Reactors to reduce the nitrogen loading to the aeration tanks, and converting some aeration tanks of the activated sludge treatment process at the Yuen Long Sewage Treatment Works to be operated as extended aeration process to reduce sludge production.


 

Siu Ho Wan Sewage Treatment Works

Shatin STW aeration tank

Shatin STW sedimentation tank

Odour Control


Odour is a common problem of sewage and sewerage. The extension of the sewage treatment works and the process modification and upgrading mentioned above help alleviate the problem. In addition, we added ferric chloride to precipitate the odour causing agent, sulfide; and added calcium nitrate to prevent its production in the sewerage handling septic sewage.

Sewerage Works in Urban Area


Construction and replacement of sewers in busy urban areas pose a unique challenge to us. We have to strike a balance between the disruption to traffic and the impact on the environment.  We need to restrict the work site area and shorten the work duration on one hand, and put in more pollution control equipment on site and limit our working hours on the other hand.   In addition to reduce road openings to a minimum, we have to implement stringent environmental control on site to properly manage dust, odour, noise and muddy discharge. Furthermore, we also set up communication channels to neighbours so that their grievances can be attended to and resolved immediately.

Works in Java Road near North Point Pier

Works in shopping district Causeway Bay