17 December 2019 MODERNISING HONG KONG’S ......TREATED GREY WATER RECLAIMED WATER THE SUPPLY OF...

MODERNISING HONG KONG’S WATER MANAGEMENT POLICY

Sustainable Water InfrastructureTowards a Diversif ied Water Supply

Report Launch - 17 December 2019

TODAY’S SPEAKERS

Natalie ChanSenior AdvisorCivic Exchange

Evan AuyangChairmanCivic Exchange

Dr David von EiffAssociate ResearcherCivic Exchange

Dr Frederick LeeFellowCivic Exchange

Evan AuyangChairman of Civic Exchange

Introductory Remarks


i

SMART

SAVE

Modernising Hong Kong’sWater Management PolicyPART II

SUSTAINABLE Water Infrastructure:TOWARDS A DIVERSIFIED WATER SUPPLY

December 2019


Natalie ChanSenior Advisor of Civic Exchange

SUSTAINABLE WATER INFRASTRUCTURE

Towards a Diversified Water Supply

An Overview

THE OBJECTIVES

To safeguard Hong Kong’s long-term

water security by leveraging different

water sources effectively

To fulfi ll Hong Kong’s responsibility to

ensure the right to water for our neighbours

in the region & our future generations

To contribute to the global ambition

of ensuring availability & sustainable

management of water for all

78%POTABLE

NON POTABLE22%

55-62%DONGJIANG WATER

16-23%LOCAL YIELD

0%DESALINATED WATER

22%SEAWATER FLUSHING

0%RECYCLED WATERHARVESTED RAINWATERTREATED GREY WATERR E C L A I M E D W A T E R

THE SUPPLY OF WATER

Source: WSD, 2019

75%POTABLE

45-60%DONGJIANG WATER

11.25-26.25%LOCAL YIELD

3.75%DESALINATED WATER

22.5%SEAWATER FLUSHING

2.5%RECYCLED WATERHARVESTED RAINWATERTREATED GREY WATERR E C L A I M E D W A T E R

NON POTABLE25%

FUTURE SUPPLY OF WATER

Source: WSD, 2019

EVALUATING THE DEPLOYMENT OF WATER SOURCES Assessment Criteria

→ Climate resilience

→ Water sustainability

→ Technical feasibility

→ Public acceptance

→ Potential for expansion

EVALUATING THE DEPLOYMENT OF WATER SOURCES

Local Yield Reservoirs in the right water catchment area, but lack an efficient water

transfer network

Dongjiang Water A critical source, but we should diversify sources of water supply to ensure

longer term sustainability of Dongjiang River

Seawater Flushing Reduce demand on freshwater, but using sea water in new towns away from

the coast is cost ineffective

Recycled Water Harvested Rainwater & Treated Grey Water – infrastructural costs vary largely,

depending on land use zoning and space availability

Reclaimed Water – independent of natural water cycle

Desalinated Water Independent of natural water cycle, but high energy intensity and unclear

impact on marine biodiversity

Major Findings

1

2

3

4

5

1 Enhance water resilience by reducing reliance on natural water cycle

2 Set an ambitious vision for the deployment of reclaimed water in non-potable uses

Reconsider the necessary conditions for deploying desalination as a backup option of freshwater supply

4 Build closer collaboration between WSD and DSD

5 Increase granularity and transparency of data to improve water supply planning

EVALUATING THE DEPLOYMENT OF WATER SOURCES Policy Recommendations

3


Dr David von Eiff Associate Researcher of Civic Exchange


Highlights of Research Findings

Water gathering ground

Impounding reservoir

MaxMax

Min

Min

Min

1600

30002800

2800

2600

24002200

20001800

Isohyets are in mm

Max2400

Rainfall Distribution & Catchment Areas

LOCAL YIELD1Local yield is gathered by the extensive rainwater collection and

storage system. Collection volume depends on rainfall distribution

and frequency.

C U R R E N T20% to 30% of freshwater supply

TA R G E T15% - 35% of freshwater supply

Sources: Hong Kong Observatory, 2003; WSD, 2019

Rainfall Collection(2002-2015)

0

500

1000

1500

2000

2500

3000

3500

Rainfall(mm)

0

500

1000

1500

2000

2500

3000

3500

Local Yield(million m3)

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Year

Rainfall

Local Yield

LOCAL YIELDAbout 50% of annual rainfall lands in the current catchment area,

but only about 10% of that is collected given the highly concentrated

nature of rainfall in Hong Kong. Hence, on average, only half of the

overall reservoir capacity was used in the last 30 years, i.e. just under

300 million m3.

Source: Civic Exchange, using data requested from Hong Kong Observatory and WSD

1

Tai TamIntermediate Reservoir

Aberdeen Lower Reservoir

Aberdeen Upper Reservoir

Tai TamByewashReservoir

Tai TamUpper Reservoir

Tai Tam TukReservoir

KowloonByewash Reservoir

Kowloon Reservoir

KowloonReceptionReservoir

Shek Pik Reservoir

Shek Lei PuiReservoir

Tai Lam Chung Reservoir

Lower Shing Mun Reservoir

Upper Shing Mun Reservoir

Plover Cove Reservoir

Pok Fu LamReservoir

High Island Reservoir

Plover Cove Reservoir & High Island Reservoir make up 87% of total capacity

LOCAL YIELDLimited potential to expand reservoirs as source of freshwater .

1

→ Majority of rainfall already captured in

water catchment areas

→ Many of the water catchment areas are

located in country parks, protected by

the Country Parks Ordinance

→ > HK$20/m3 to increase capacity , with

payback period of over 250 years and

will not signifi cantly increase reliability

of supply

Sources: SCMP, 2018; Civic Exchange, using data requested from WSD

LOCAL YIELDReservoirs offer additional benefi ts in fl ood control, however,

Inter-reservoirs Transfer Scheme is currently ineffi cient.

→ Annual average loss of 19.8 million m3 (2009-2014)

→ Diversion of rainfall can help mitigate concern on

fl ooding during time periods when fl ooding was

historically problematic

1

Year

Supply Ceiling

vs

Actual Volume Supplied

of Dongjiang Water

(2006-2017)

Volume of Water(million m3)

550

600

650

700

750

800

850

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Supply ceiling

Actual volume

supplied

C U R R E N T70% to 80% of freshwater supply

TA R G E T60% - 80% of freshwater supply

DONGJIANG WATER

Source: WSD, 2006-2017

→ Current agreement guarantees Hong Kong 820 million m3 per year,

regardless of drought conditions in the Pearl River Delta

→ Hong Kong typically used about 640 million m3 on a 10-year average

2

→ Dongjiang water makes up the bulk of WSD’s spending

→ Increased from 37.8% of overall expenses in 1997 to 45% in 2018

→ Since the user-pays principle no longer holds as full cost of

present-day water supply is not refl ected in the price of water,

WSD is in constant defi cit

→ Cost of Dongjiang water has more than doubled over the past

10 years to HK$4.76 billion and continues to grow at 3-6% per year

DONGJIANG WATER2

DONGJIANG WATER Average rate of increase in the price of Dongjiang water from

2009-2018 was 6.8%. Since the full 820 million m3 is not used,

the actual rate of price increase was even higher.

HKD 130

HKD 181

HKD 100

*Using the Hong Kong Composite Consumer Price Index (CPI) as a reference between 2009 – 2018

*Infl ation rate

3%

39%

OVER 10 YEARS

Dongjiang water

6.8%

2

Dongguan & Shenzhen

0

1000

2000

3000

4000

5000

6000

2011 2012 2013 2014 2015 2016

Dongshen Project Revenue Dongshen Project Water Utilisation

0

20%

40%

60%

80%

100%

2011 2012 2013 2014 2015 2016

HK$ million

DONGJIANG WATER

Sources: Guangdong Investment, 2011-2016; GF Securities (Hong Kong), 2017

2

Hong Kong

DONGJIANG WATER Dongjiang water is a critical source of freshwater supply to Hong Kong,

but Hong Kong should begin to develop alternatives to reduce its reliance

on Dongjiang water which counts on natural water cycle. Developing

alternatives will also enhance Hong Kong’s price negotiation position.

2

Pumping Station

Sea Level Sea Wall Intake Culvert

Customers Customers

Non return Valve

Customers Customers

ServiceReservoirTypical Seawater supply system (schematic)

C U R R E N T100% of non-potable water supply

TA R G E T90% of non-potable water supply

SEAWATER FLUSHING3Hong Kong maintains a dual-reticulation plumbing system to deliver

fresh and seawater

→ offset a signifi cant proportion of freshwater use for the last 60 years

→ economical alternative to fresh water for fl ushing

Source: WSD, 2019

SEAWATER FLUSHING → The economics of seawater fl ushing vary, primarily depending on

population density and distance from coast

→ Further expansion into more remote areas requires signifi cantly

more capital investment, making the cost of seawater fl ushing less

competitive compared to alternative water resources

3

Existing Seawater Supply Zone

Expanding Seawater Supply Zone

Seawater Supply Zones &

Location of proposed New Towns

SEAWATER FLUSHING → The expansion of seawater zone in the Northwest New Territories in

2014-2015 covers an additional 5% of the population

→ Before expansion, average cost of supply = HK$3.4 per m3

→ After expansion, average cost of supply increased 25% to HK$4.26 per m3

Source: WSD, 2019

3

RECLAIMEDWATER

HARVESTED RAINWATER& TREATED

GREY WATER

RECYCLEDWATER

C U R R E N T0% of non-potable water supply

TA R G E T10% of non-potable water supply

RECYCLED WATER4

HARVESTED RAINWATER

Rainwatercollected & stored

for use

TREATED GREY WATER

Treated water collected from

showers, kitchen sinks & laundry machines

etc.

RECLAIMEDWATER

HARVESTED RAINWATER& TREATED

GREY WATER

RECYCLED WATER

Reused for on-site non-potableuses such as toilet flushing

HARVESTED RAINWATER& TREATED GREY WATER4.1

4.1 HARVESTED RAINWATER& TREATED GREY WATERHarvested rainwater→ Considerations for determining the practicality of harvesting

infrastructures

→ Available space

→ Water quality

→ Treatment costs

→ On-site demand

→ Focus areas: urban residential & commercially zoned

→ About 81 km2 of land may be promising for harvesting around

14.48 million m3/year

→ Sites located in Jordan Valley, Kowloon City, Lai Chi Kok and

Happy Valley

A. Collect Rainwater

At The Roof

B. Sand Filtration and UV Disinfection

C. Reuse Rainwater for Irrigation and other Non-Potable Uses

D. Obtain Freshwater From Water

Supply During Dry Season

HARVESTED RAINWATER & TREATED GREY WATERRainwater harvesting facilities at Kowloon City No. 1 and No. 2

Sewage Pumping Stations

4.1

Source: DSD, 2017

Ground Water

Sports Pitches Rain Water

Used as Irrigation Water at Sports Pitches

Used as Flushing Water

TreatmentPlant

Underground Stormwater Storage Tank

Subsoil Drains

Toilet Flushing

Untreated

Water

Storage

Chamber

Treated

Water

Storage

Chamber

Irrigation Water

HARVESTED RAINWATER & TREATED GREY WATER4.1Happy Valley Water Harvesting System

Source: DSD, 2016

HARVESTED RAINWATER & TREATED GREY WATERHarvested rainwater → An expensive approach in Hong Kong

→ Limited available space

→ Mixed land use zoning affecting water quality

→ Highly variable cost (HK$2.86-HK$231)

→ Must be on a large scale to be economically viable

→ Typical rooftop system only provides 25% of water needed for

washing machines in a high-rise building

Treated grey water→ Stable water supply within the system, contrary to rainwater

harvesting which depends on the natural water cycle and hence

has lower climate resilience

4.1

HARVESTED RAINWATER & TREATED GREY WATERThe economics and feasibility of harvested rainwater and treated

grey water are site specifi c

→ Diffi cult for single private building owners to justify retrofi tting

without incentives, meaning they are more inclined to solely

depend on the conventional freshwater supply system that relies

upon local yield and Dongjiang water

4.1

Other Non-Potable Use To Toilet Flushing

Water Reclamation Plant Sewage Treatment Plant

RECLAIMED WATERWastewater treated to meet high standards and local regulations for

non-potable uses

→ Not reliant on natural fl ows

→ DSD pilot scheme, Ngong Ping Sewage Treatment Works,

commissioned in 2006; 11 additional small-scale water reclamation

trial plants commissioned later in 2010

4.2

Source: WSD, 2017

RECLAIMED WATER International examples Maximising Potential Comparable to Hong Kong:

→ Similar demand for water among sectors, standard of living,

overall water resources

→ Dependent upon imported water for a majority of its supply

Today, there are fi ve NEWater plants supplying up to 40% of

Singapore’s current water needs. By 2060, NEWater is expected

to meet up to 55% of Singapore’s future water demand.

→ Majority used for industrial sector and 10% placed in reservoirs

for reuse

→ By 2002, 82% of public respondents indicated willingness to

drink reclaimed water directly

4.2

Faecal & Total Coliforms(Means) 1.00E+02

1.00E+01

1.00E+00

1.00E+03

1.00E+04

1.00E+05

1.00E+06

1.00E+07

PlantFeedwater

MFFiltrate

ROPermeate

NEWater PUB Raw Water

PUB Drinking Water

Concentration(CFU/100mL)

Faecal Coliform

Total Coliform

4.2Challenges with regards to public acceptanceStrict regulations in Singapore have made NEWater

just as safe, if not safer than traditional sources

RECLAIMED WATER International examples

Source: PUB NEWater Expert Panel, 2012

Adoption through regulatory change

→ Upgraded wastewater treatment leading to a signifi cant

diversifi cation in the permitted uses

→ 47 approved uses of reclaimed water at the state level,

e.g. irrigation, industrial or commercial cooling, supply for

recreational impoundment, toilet fl ushing

→ Municipalities have the fl exibility to pick and choose the ones that

best suit their circumstances

→ Grants and low-interest loans available for public agencies to

investigate the feasibility of reclaimed water projects, with hopes of

securing 30-50% of the supply by 2050

RECLAIMED WATER International examples 4.2

Desalination is the process that separates dissolved salts and

minerals from water

→ Tseung Kwan O Desalination Plant planned for 2022 completion,

with capacity of supplying 5%-10% of overall freshwater demand in

Hong Kong

Tseung Kwan O Desalination PlantSource: WSD

C U R R E N T0% of potable water supply

TA R G E T5% of potable water supply

DESALINATED WATER5

T S E U N G KWA N O

Energy-intensive

→ Production of each m3 of water requires 6-8 times as much

electricity as our current fresh water does to produce and distribute

→ More electricity use means higher carbon footprint as current

power production relies on fossil fuel

→ WSD already accounts for 53.8% of the Government’s electricity use

Potentially environmentally damaging

→ Brine disposal (concentrated salt water) may severely

affect reproduction and growth of marine organisms

DESALINATED WATER5

LOCALYIELD

PO

TA

BL

E

CURRENT AVERAGEUNIT PRICE

CLIMATERESILIENCE ADAPTABILITY

NO

N-P

OT

AB

LE

FL

US

HIN

GO

NLY

DONGJIANG WATER

DESALINATEDWATER

HARVESTEDRAINWATER

TREATEDGREYWATER

RECLAIMEDWATER

HK$4.20 LOW

LOW

HIGH*

HIGH

HIGH

HIGH

HIGH

LOW

LOW

LOW

LOW - MEDIUM**

HIGH

HIGH

LOWSEAWATERFLUSHING

HK$10.13

HK$2.86 - HK$231

HK$1.50 - HK$16

HK$6.50

HK$4.26

HK$12 - HK$13

* Guaranteed by purchase agreement

** As Hong Kong will continue to phase down coal for electricity generation and use more natural gas and increase

non-fossil fuel sources, the climate-related shortcomings of energy-intensive water resources will gradually decrease.

Advances in energy storage systems will also make the use of renewable energy more practicable over time.

WATER SNAPSHOT

Dr Frederick Lee Fellow of Civic Exchange



Policy Recommendations

POLICY RECOMMENDATIONS

Considerations

→ Climate resilience

→ Water sustainability

→ Technical feasibility

→ Public acceptance

→ Potential for expansion

POLICY RECOMMENDATIONS

Enhance water resilience by reducing reliance on natural water cycle

Set an ambitious vision for the deployment of reclaimed water in non-potable uses

Reconsider the necessary conditions for deploying desalination as a

backup option of freshwater supply

Build closer collaboration between WSD and DSD

Increase granularity and transparency of data to improve water supply planning

1

2

3

4

5

→ For the purposes of securing Hong Kong’s long-term sustainability and

fulfi lling our regional responsibility, rely less on natural water cycle, e.g.

Dongjiang water, by investing more on alternatives

→ As the current Dongjiang water purchase agreement expires in 2020,

the Hong Kong government can consider to

→ Renegotiate the nature of the agreement with the Guangdong

authorities to maintain stability of Dongjiang water prices over the years

→ Set a lower fi xed portion with a variable portion available as needed, which

could even be charged at a higher price to encourage conservation efforts

Reduce reliance on natural water cycle

1

Set an ambitious vision for the deployment of reclaimed water in non-potable uses→ 20% reclaimed water = savings of 197 million m3

1. Freshwater fl ushing areas

2. Other non-potable demand

→ Construction, industrial and government: do not require high quality

fresh water and have low public exposure

→ A small portion of the service sector: the most challenging from a public

acceptance standpoint as it has high public exposure

2

Attributes for considering the viability of desalination

→ Cost-benefi t

→ Minimum volume of desalinated water required to make the option

economically viable

→ Energy use

→ WSD is currently one of the largest users of electricity in Hong Kong and

desalination may substantially increase its use and hence carbon emissions

→ Transitioning to the use of clean energy would therefore lessen the impacts

→ Marine conservation

→ Brine disposal may severely impact marine ecosystems

According to the latest TWM 2019, WSD will be using desalinated water to supply 3.75% of Hong Kong’s total water supply (or 5% of fresh water supply)

Reconsider the necessary conditions for deploying desalination as a backupoption of freshwater supply

3

→ The work of WSD and other government departments, especially the

Drainage Services Department (DSD), has an impact on each other through

their decision-making; the synergetic benefits might make projects

traditionally considered too expensive to be more cost-effective

→ Benefits of collaboration:

→ Flood control (Inter-reservoirs Transfer Scheme)

→ Grey water from sinks for flushing

→ Run-off recycled onsite for use before being diverted to the flood pond

Closer collaboration between WSD & DSD & other government departments

4

Current practices

→ Unmetered seawater fl ushing

→ Metered freshwater fl ushing only at the building level

→ Lack of timely access to usage information

Challenges created

→ Diffi cult for users to quickly notice and respond to peaks or receive positive

feedback about conservation efforts

→ Unable for WSD to determine true effi ciency of the system and to compare

it with potential alternatives

Increase granularity and transparency of data to improve water supply planning

5

Question & Answer Session

Sustainable Water InfrastructureTowards a Diversif ied Water Supply

Dr David von Eiff Associate Researcher

Dr Frederick Lee Fellow

Ms Natalie Chan Senior Advisor

水資源管理政策現代化

可持續供水系統邁向多元化的水源

研究發布會 - 二零一九年十二月十七日

講者

陳琦高級顧問思匯政策研究所

歐陽杞浚主席

思匯政策研究所

David von Eiff 博士副研究員


李煜紹博士資深學人


歐陽杞浚思匯政策研究所主席

序辭


i

SMART

SAVE

Modernising Hong Kong’sWater Management PolicyPART II

SUSTAINABLE Water Infrastructure:TOWARDS A DIVERSIFIED WATER SUPPLY

December 2019


可持續水務基建

邁向多元化供水系統

概要

陳琦女士思匯政策研究所高級顧問

目標

通過有效利用各種水源來維護香港長遠

供水穩定

履行香港的責任，確保鄰近城市及下一代有可

靠的供水

為實現全球目標出一分力：確保人人

有水用和達致可持續水資源管理

78%飲用

22%非飲用

55-62%東江水

16-23%本地集水

0%海水化淡

22%海水沖廁

0%循環再用水中水重用雨水回收再造水

供水系統

來源: 水務署, 2019

75%飲用

45-60%東江水

11.25-26.25%本地集水

3.75%海水化淡

22.5%海水沖廁

2.5%循環再用水中水重用雨水回收再造水

25%非飲用

未來供水系統

來源: 水務署, 2019

審視水資源調配

評估標準

→ 氣候抗禦力

→ 水源可持續性

→ 技術可行性

→ 公衆接受程度

→ 擴充潛力

審視水資源調配

本地集水水塘已興建在適當的集水區内，但水塘間欠缺有效率的輸水網絡

東江水不可或缺的水源，但同時應開發其他水源，確保東江流域水源的可持續性

海水沖廁減少對淡水的需求，但在離岸較遠的新市鎮使用海水不符合成本效益

循環再用水回收雨水及重用中水 – 基建工程的成本差異很大，取決於土地用途劃分及可用空間

再造水 – 不用依賴天然水循環系統

海水化淡不用依賴天然水循環系統，但能源需求大，對海洋生態可能帶來潛在影響

主要研究結果

1

2

3

4

5

1 增强水資源抗禦力，減少對天然水循環系統的依賴

2 為再造污水作非飲用用途訂立更進取的願景

重新審視採用海水化淡作為後備水源的必要條件

4 水務署與渠務署之間建立更緊密的協作

5 提升數據的精準度和透明度以改善供水系統

審視水源調配

政策建議

3



主要研究成果

David von Eiff 博士思匯政策研究所副研究員

集水區

水塘最低

最低

最低

1600

3000 最高 2800

最高

2800

2600

24002200

20001800

等雨量線單位為毫米

最高

2400

雨量分布和集水區

1 本地集水本地集水是一個龐大的雨水收集及貯存系統。

水塘位置取決於雨水分布和頻率。

現時

食水供水20%-30%

目標

食水供水15%-35%

來源：香港天文台，2003；水務署， 2019

降雨收集量 (2002-2015)

0

500

1000

1500

2000

2500

3000

3500

降雨量(毫米)

本地集水(百萬立方米)

3500

3000

2500

2000

1500

1000

500

0

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

年份

降雨

本地集水

本地集水

每年大約有50%的雨水落入集水區，但由於降雨高度集中，水塘只儲

存到當中約10%。因此在過去30年，每年平均只用了水塘一半的儲水

量，即不到3億立方米。

來源：思匯政策研究所，使用香港天文台及水務署提供的數據

1

大潭中水塘

香港仔下水塘

香港仔上水塘

大潭上水塘

大潭副水塘

大潭篤水塘

九龍接收水塘

石壁水塘

石梨貝水塘

九龍水塘

九龍副水塘

大欖涌水塘

下城門水塘

城門水塘

船灣淡水湖

薄扶林水塘

萬宜水庫

船灣淡水湖和萬宜水庫佔總儲

水量的87%

本地集水擴大水塘作為淡水水源的效用有限。

1

→大部分雨水已落在集水區

→許多集水區都位於郊野公園內，

受《郊野公園條例》保護

→水塘容量每增加一立方米，成本是20港

元，投資回本期超過250年，也不會顯

著提高供應的可靠性

來源：南華早報，2018；思匯政策研究所，使用水務署提供的數據

本地集水

水塘在防洪方面提供額外效益，但現時的水塘間轉運隧道計劃

效率不高。

→每年平均損失1,980萬立方米食水（2009-2014）

→在水浸較嚴重的時期轉運雨水，能減低水災風險

1

年份

東江水的最高供水量和

實質供水量

(2006-2017)

水量（百萬立方米）

550

600

650

700

750

800

850

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

最高供水量

實質供水量

現時食水供水70%-80%

目標

食水供水60% - 80%

東江水

來源：水務署，2006-2017

→無論珠江三角洲的乾旱情況如何，現時協議都保證香港每年有

8億2千萬立方米食水

→香港每年平均使用6億4千萬立方米

2

→ 東江水佔水務署大部分的支出

→ 由1 997年的37.8%，增加到2018年的45%→ 由於東江水的全部成本未能反映在水價中，用者自付原則未能

落實，因此水務署一直處於赤字狀態

→ 東江水的成本在過去10年倍增至港幣47.6億元，並每年持續上升3-6%

2 東江水

東江水東江水在2009-2018年間的平均漲幅為6.8%。由於未用盡

8億2千萬立方米的全額，實質價格上漲幅度會更高。

港幣 130 元

港幣 181 元

港幣 100 元

*以2009-2018年的綜合消費物價指數作參照

*通脹率

3%

39%

10年間

東江水

6.8%

2

東莞和深圳

0

1000

2000

3000

4000

5000

2011 2012 2013 2014 2015 2016

東深供水工程收入東深供水工程用水

0

20%

40%

60%

80%

100%

2011 2012 2013 2014 2015 2016

百萬港元

6000

東江水

來源: 粤海投資有限公司年報, 2011-2016; 廣發控股（香港）, 2017

2

香港

東江水

東江水是香港的重要食水來源，但香港必須戮力發展替代水源來減少對東

江水的依賴，避免依靠天然水循環系統。發展替代水源亦可增強香港的議

價能力，爭取一個更合理的價格。

2

抽水站

水平面海提進水口用戶用戶

單向閥

用戶用戶

配水庫典型海水供應系統（概要）

現時

非飲用水供水100%

目標

非飲用水供水90%

3 海水沖廁香港使用兩套供水系統，分別輸送食水和沖廁用的海水

→在過去60年抵消了大量食水使用→較經濟的選項代替食水沖廁

來源：水務署，2019

海水沖廁

→海水沖廁是否符合經濟效益，主要取決於人口密度和與海岸的距離

→進一步擴展到偏遠地區需要大量資金，令海水沖廁的效益遜於其他水源

3

現時海水供應範圍

計劃發展的海水供應範圍

海水供應網絡及擬建新市鎮

海水沖廁

→政府在2014-15成功將沖廁海水管網絡延伸至新界西北，令涵蓋人口增加5%

→擴建前平均供應成本為每立方米HK$3.4

→擴建後平均供應成本增加25%至每立方米HK$4.26


3

再造水

中水重用及雨水回收

循環再用水

現時

非飲用水供水的0%

目標

非飲用水供水的10%

4 循環再用水

雨水回收收集並儲存雨水以供使用

中水重用從浴室、廚房

和洗衣機等收

集並經過處理

的中水

再造水


循環再用水在現場重用，作非飲用用途，如沖廁

中水重用及雨水回收4.1

4.1 中水重用及雨水回收

雨水回收→雨水回收配套的實際考慮

→ 儲存空間

→ 水質

→ 水質處理費用

→ 現場需求

→ 重點地區: 市區住宅和商業區

→ 要做到每年回收約 1,448萬立方米雨水，需要大約81平方公里的土地

→ 佐敦谷、九龍城、荔枝角、跑馬地設有雨水回收系統

A.從綠化天台收集雨水

B.砂濾和紫外光消毒

C.重用雨水作灌溉及其他非飲用用途

D.天旱時以食水作後備供水


九龍城一號及二號污水泵房的雨水集蓄設施

4.1

來源：渠務署，2017

地下水

運動場雨水

在運動場上用作灌溉

用來沖廁

污水處理設施

地底蓄洪池

底土排水系統

沖廁

未經處理的

水源

儲存

設施

已處理的

水源

儲存

設施

灌溉用水

中水重用及雨水回收4.1跑馬地雨水回收系統

來源：渠務署，2016


雨水回收 →在香港是一個昂貴的方法

→可用空間有限

→混合土地用途影響水質

→成本變數多（港幣2.86元-231元）

→必須大規模實施，經濟上才可行

→典型的屋頂雨水回收系統，只足夠一棟大廈的洗衣機25%用水量

中水重用→供水穩定，有較强的抗禦氣候變化能力，與須倚靠天然水循環系統

的雨水回收相反

4.1


經濟效益和可行性，將因應選址而不同

→單棟私人樓宇的業主缺乏誘因改變食水水源，意味他們較傾向採用

現有的食水供應系統，就是本地集水及東江水

4.1

其他非飲用用途沖廁用途

再造水設施污水處理設施

再造水

經過處理的污水，淨化後符合高標準和本地法規，適合非飲用用途

→不依賴天雨

→渠務署於2006年啟用昂坪污水處理廠；2010年進行1 1項小規模

再造水試驗計劃

4.2


再造水海外例子加強潛力與香港可作比較：

→不論是各行業對水的需求、生活水平，或水資源總量，也非常相似

→大部分水資源都依賴進口

新加坡現時有5座NEWater處理廠，為當地提供40%用水。

到2060年，NEWater將為新加坡提供高達55%的用水。

→再造水大多用於工業界，另10%儲放在水塘供市民重用

→在2002年，82%公眾受訪者表示願意直接飲用再造水

4.2

大腸桿菌和總細菌含量（平均） 1.00E+02

1.00E+01

1.00E+00

1.00E+03

1.00E+04

1.00E+05

1.00E+06

1.00E+07

PlantFeedwater

MFFiltrate

ROPermeate

NEWater PUB Raw Water

PUB Drinking Water

濃度（菌落形成單位/100毫升）

大腸桿菌含量

總細菌含量

4.2公眾接受程度的挑戰新加坡嚴格的監管令NEWater的水質達致與傳統水

源的標準，甚至更安全

再造水海外例子

來源： PUB NEWater Expert Panel, 2012

透過改變法規而採用

→污水處理水平逐漸提升，令再造水的用途變得更多元化

→加州政府批准了再造水的47個用途，包括灌溉、工業或商業冷卻系

統、康樂用水、沖廁

→個別城市可按照自己的情況，自由選擇最適合他們的用途

→公共機構可獲得津貼和低息貸款，進行研究再造水的可行性，希望

到2050年達致30-50%的供水量

再造水海外例子 4.2

從海水中抽走已溶解的鹽分和礦物質

→ 將軍澳海水化淡廠計畫於2022年完工，可為香港提供5%-10%的淡水

Tseung Kwan O Desalination PlantSource: WSD

現時

食水供水的0%

目標食水供水的5%

5 海水化淡

將軍澳

能源需求大

→海水化淡需要的電力，是目前生產和輸送淡水所需電力的6-8倍

→用電量更多意味著更高的碳足跡，因為香港目前的電力生產依賴化

石燃料

→水務署已經佔政府用電量的53.8%

潛在環境破壞

→化淡廠釋放的高濃度鹽水，可能嚴重影響海洋生物的繁殖和生長

5 海水化淡

本地集水

飲用用途

現時每立方米成本抗禦氣候變化的能力適應能力

非飲用用途

只限沖廁用途

東江水

海水化淡

雨水回收

中水重用

再造水

港幣4.20元低

低

高*

高

高

高

高

低

低

低

低 - 中**

高

高

低海水沖廁

港幣10.13元

港幣2.86-231元

港幣1.50-16.00元

港幣6.50元

港幣4.26元

港幣12.00-13.00元

*透過供水協議獲得保證

** 隨著香港將逐步淘汰煤炭發電並使用更多天然氣及非化石燃料，將可逐漸減少因開發水資源需要大量能

源而影響氣候的缺點。而能源儲存系統的進步，也將令可再生能源的使用更切實可行。

水資源簡介



政策建議李煜紹博士思匯政策研究所資深學人

政策建議

考慮因素

→ 氣候抗禦力

→ 水源可持續性

→ 技術可行性

→ 公衆接受程度

→ 擴充潛力

政策建議

增强水資源抗禦力，減少對天然水循環系統的依賴

為再造污水作非飲用用途訂立更進取的願景


水務署與渠務署之間建立更緊密的協作

提升數據的精準度和透明度以改善供水系統

1

2

3

4

5

→確保香港的可持續發展並履行香港的地區責任，發展替代水源來減少對天然水

循環系統的依賴，例如東江水

→現時的東江水供水協議將在2020年到期，香港政府可以考慮

→與廣東省部門重新談判協議的性質，穩定東江水價格

→減低東江水每年保證輸港上限，在有需要情況下才購買非固定的水量，甚至

可以考慮收取更高價格，以鼓勵節約用水

增强水資源抗禦力，減少對天然水循環系統的依賴

1

為再造污水作非飲用用途訂立更進取的願景

→ 20%再造水 = 節省1.97億立方米

1.淡水沖廁

2.其他非飲用用途

→建築、工業和政府部門用水: 無需高質素的食水，同時與市民的接觸面較小

→一小部分服務業用水：從公眾接受的角度來看最具挑戰，因爲與市民的接

觸面較大

2

海水化淡可行性的考慮因素

→成本效益

→令海水化淡合乎成本效益的最少供水量

→能源需求→水務署現時是香港最大電力用家之一，海水化淡只會大幅增加用電量，加劇碳排放

→採用清潔能源，減低對環境的影響

→海洋生態保育

→棄置高濃度鹽水有可能嚴重影響海洋生態系統

根據最新的《全面水資源管理策略

2019》，水務署將會用海水化淡為全港供水3.75%（即食水的5%）


3

→水務署與其他政府部門，特別是渠務署的工作環環相扣，會因彼此的決策而互

相影響。協同效益能令一直被認爲太昂貴的項目，變得符合成本效益

→協作效益包括：

→防洪（水塘間轉運隧道計劃）

→將從洗手盆收集的中水，重用於沖厠

→轉運徑流至蓄洪池前，先即場重用

水務署與渠務署之間建立更緊密的協作

4

現時做法

→海水沖廁用量未經水錶記錄

→只以大廈為單位經水錶記錄淡水沖廁用量

→缺乏即時用水資訊

造成的挑戰

→用戶難以適時地留意到用水量過高而作出反應，或得知有關節約用水努力

的成效

→水務署難以評估系統的真正效率，並與其他替代水源作比較

提升數據的精準度和透明度以改善供水系統

5

問答環節

可持續供水系統邁向多元化的水源

David von Eiff 博士副研究員

李煜紹博士資深學人

陳琦女士高級顧問

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