Learning From Singapore’s Circular Water Economy
By Julian Kirchherr, Ralf van Santen 17 November, 2017
Kirchherr & van Santen show how Singapore is developing a powerful circular water economy
Hong Kong is surrounded by green hills and faced with heavy rainfall during its three-month rainy season. Water supply appears to be unlimited during this time. However, the city state is actually a water scarce region that relies significantly on water imports to meet its needs. Since the 1960s the Dongjiang River that runs through neighbouring Guangdong province, China, provides approximately 80% of Hong Kong’s freshwater.
However, Guangdong has recently been found to be one of the 14 provinces in China that failed to meet their 12th Five Year Plan (12FYP) water quality targets. This is caused by insufficient wastewater treatment and low sewage discharge standards.
The Dongjiang River is supposed to provide water for over 40 million people. Cities are allocated a certain volume they are allowed to use to ensure sustainable levels of withdrawal from the river. However, many of the cities’ demands already exceed their allocated volume. This is about to also hold true for Hong Kong whose demand is projected to meet its allocation quota by 2020.
Hong Kong faces an imminent water crisis…
… like Hong Kong, is in a critical water situation
Hong Kong thus faces an imminent water crisis. Some lessons on how to overcome this crisis may be learnt from Singapore.
Like Hong Kong, Singapore lacks sufficient natural water resources. The country started importing water from Malaysia in 1927 already. Today, imported water meets up to 60% of Singapore’s needs. However, Singapore is experiencing political tensions with Malaysia with the importing agreement with Malaysia expiring in 2061 in any case. At the same time, experts project a doubling of Singapore’s water demand by 2060. Singapore is thus in a critical water situation.
Singapore’s circular water economy
In response, Singapore has been at the forefront of developing what is now called a circular water economy. While water becomes successively more polluted in a linear system, a circular water economy aims to reduce pollution to enhance future use. The circular water economy thus rests on maximizing water reuse. Additional pillars of the circular water economy are freshwater demand reduction, and increased rainwater retention.
Singapore has been at the forefront of developing what is now called a circular water economy
… from maximizing water reuse, to reducing freshwater demand, to increasing rainwater retention
The Singaporean government has adopted ambitious plans to increase the rates of reused water. Reclaimed wastewater is recycled into NEWater. The five existing NEWater plants meet 40% of water demands today. Singapore aims to increase this share to 55% by 2060 by extending their production. NEWater is used for non-potable tasks, but during dry spells it also tops up existing freshwater reservoirs.
To reduce freshwater demand, water tariffs are currently being raised by 30% in two steps…
To reduce freshwater demand, water tariffs are currently being raised by 30% in two steps. The first raise took place in July 2017; the second will be in July 2018. The government regards it as an important and effective measure to reduce consumption. Indeed, after the raise in 2000 the per capita consumption in Singapore declined from 165 litres back then to 148 litres today. Furthermore, a mandatory labelling scheme promotes the use of water conserving fixtures and appliances in Singapore.
Finally, the government seeks to raise public awareness regarding water conservation practices through campaigns and public spaces that incorporate water bodies. Singapore hopes to reduce the per capita consumption to 124 litres by 2060.
…the government is also targeting an increase in harvested rainwater
66% of Singapore’s surface is already regarded a catchment area with the country overall featuring 17 catchment areas that harvest rainwater. Their share will increase by protecting previously unprotected water bodies to make them suitable for potable use. A separate underground sewerage system collects harvested urban storm water, ultimately suitable for large-scale consumption. The government targets a 15% share of harvested rainwater by 2060.
Our own tentative calculations quantify the impact of Singapore’s circular water economy. By 2060, 730 million cubic metres of freshwater are saved compared to a business-as-usual scenario. However, implementing such a circular water economy is costly. The main cost drivers are NEWater processing and rainwater retention costs, with NEWater processing costing USD0.3 per cubic metre for instance. These costs are justified, though, considering that water scarcity can decrease GDP growth by up to 6 percentage points.
By 2060, 730mn m3 of freshwater are saved compared to a business-as-usual scenario…
…costs of a circular water economy are justified as water scarcity can decrease GDP growth by 6 percentage points
How Hong Kong can learn – from pricing reform to reducing leakage
Hong Kong can draw valuable lessons from the described circular water economy actions. Unlike Singapore, Hong Kong prohibits the use of reclaimed wastewater for potable ends. However, instead of pumping it into the sea, sufficiently treated wastewater could be used for non-potable tasks, such as irrigation and industrial cooling – just as it is in Singapore.
Hong Kong has one of the lowest water tariffs in the world
Like Singapore, Hong Kong could also reduce per capita consumption through water pricing reforms. Hong Kong has one of the lowest water tariffs in the world that subsequently fails to incentivize water conservation. Consequently, at 224 litres per capita per day, consumption is over 50% more than Singapore’s per capita consumption.
Finally, deepening existing catchment areas and utilization of harvested storm water can increase water retention capacities in Hong Kong. Currently, 17 catchment areas harvest approximately 20% of total needs. Yet more harvesting facilities can be incorporated in public spaces, as demonstrated by Singapore. Additionally, existing properties can be retrofitted with green roofs and walls to enhance rainwater retention capacities.
Finally, there are also low hanging fruits beyond the circular water economy that can lessen Hong Kong’s dependence from water imports. Most importantly, Hong Kong should address the significant leakages from its network. In 2015, approximately 33% of the total water supply was lost by leakages.
Hong Kong has already started to implement some circular water economy actions…
…but more ambitious water reuse & reduction efforts are needed
Admittedly, Hong Kong has already started to implement some circular water economy actions. For instance, properties are increasingly provided with grey water, while seawater is used to flush toilets, which has reduced freshwater demand by 20%. Furthermore, the government attempts to reduce per capita consumption through awareness campaigns, instalment of water saving devices in various types of premises, and developed conservation practices with high water-consuming sectors. However, many more actions need to be undertaken to ensure Hong Kong’s water security.
Singapore demonstrates that a circular water economy can be a powerful answer to a looming water crisis. Hong Kong may be able to learn much from Singapore’s approach. While Hong Kong already implemented several of the circular water economy’s features, more ambitious water reuse and reduction efforts as well as additional water retention capacities could ensure greater resilience of Hong Kong’s water system.
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