Tackling stormwater and
wastewater in Hong Kong

By Ir Chi-chiu Chan

President, Hong Kong Institution of Engineers (HKIE)

It is difficult not to notice in the news that there are serious flooding incidents and severe droughts in different parts of the world every now and then, and it seems to be getting more and more frequent. Developed countries and advanced economies are not immune. Even though there are still on-going discussions among the experts as to the seriousness of climate change, or whether climate change is induced by human activities or not, we cannot just stay put without planning and doing something to tackle the problem.

Hong Kong is a highly urbanized city, where we have more skyscrapers than most other cities and our ground surface largely paved with hard covers. We are also one of the major cities with the highest annual average rainfall. In the past decades, a lot of effort has been spent to improve the stormwater drainage infrastructure, such as the award-winning stormwater drainage tunnels in different parts of Hong Kong, thereby reducing the risk of flooding in the urban centres. But that is not enough. On completion of these major construction projects, we also need to look into other management methods, one of which is rainwater harvesting. This method is being practiced in some public and private housing developments, and the water so collecting is used for irrigating landscaped areas, street cleansing and the like. If we are to look only at the cost of fresh water so saved and calculate the payback period, then the rainwater harvesting system is doomed from the start. But it does have a promising future in Hong Kong, as it not only improves the resilience of the stormwater drainage system, but also reduces our demand for fresh water, another issue for this water-scarce city.

Hong Kong relies on importing raw water from Mainland China to meet some 70 to 80% of its demand. We can foresee a growing demand for water in Hong Kong yet an increasing competition for the same water source from other Mainland cities. To plan for the future, we need to look for other possible water resources. Water reclamation has been studied and tested successfully at different sewage treatment works in Hong Kong. On top of treating the wastewater to meet the discharge standard, part of it is further processed for re-use in non-potable purposes such as toilet flushing and landscape irrigation. This approach has a good prospect, as Hong Kong seeks to increase its water resources to meet the needs of the growing population, but at the same time wishes to contain the pollution loading from the treated sewage effluent to some sensitive receiving water bodies. Along the same line, grey water reuse can be introduced to building developments of varying scales to achieve the same objectives, if sufficient incentive is provided to the property developers.

To take forward rainwater harvesting and water reclamation will require the coordinated effort of different government departments, but definitely worth pursuing. Alternatively, we can consider bringing all the relevant departments in charge of stormwater management, wastewater treatment and water supply under one roof to enhance co-operation and effective administration.

Biography – Ir CHAN Chi Chiu

Ir Chan is a civil engineer by profession. After graduation from the University of Hong Kong in 1976, he worked in the then Highways Office and Drainage Division of the Government for two years, and then continued his engineering career in the Water Supplies Department. He has been involved in the planning, design and construction of new waterworks projects, operation and maintenance of the water supply and distribution system, and the provision of customer services. In 2008, he was transferred to the Civil Engineering and Development Department, taking charge of the planning, management and implementation of development and infrastructure projects in the North and West New Territories. From September 2010 to February 2014, he was the Director of Drainage Services, overseeing all aspects of wastewater and stormwater drainage services, covering capital projects for new infrastructure, improvement works to existing assets, operation and maintenance of existing systems and facilities, and collection of sewage services charges. He is currently the President of the Hong Kong Institution of Engineers and an Adjunct Professor of the Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology.