jakarta green building user guide vol. 5 water … · it represents only the total volume of water...

JAKARTA GREEN BUILDING USER GUIDE

VOL. 5

WATEREFFICIENCY

The Government of the Province ofJakarta Capital Special Territory

Didukung oleh: IFC bekerjasama dengan:

C O D E R E Q U I R E M E N T S

Water Efficiency (WE) WE01 Minimum Water Fixture Efficiency WE02 Sub-metering of Water Supply WE03 Greywater Recycling

The calculation should be done using the calculator

available on this website

http://greenbuilding.web.id

Checklist for all code requirements lists the required

documents is also available on this website

http://greenbuilding.web.id

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table of contents

C O D E R E Q U I R E M E N T01

INTRODUCTION

Water Supply in Jakarta

Flooding and Fresh Water Loss

Groundwater Over-expliotation and Land Subsidence

EFFICIENT FIXTURES

Water Efficient Flushing System

Water Efficient Fixtures

SUB-METERING OF ALL MAJOR WATER CONSUMING SYSTEMS

GREYWATER REUSE

COOLING TOWER WATER EFFICIENCY

CONDENSATE WATER HARVESTING

RAINWATER HARVESTING

Catchment Area

Gutter

First Flusing

ABSORPTION WELL

Bioretention System

WATER EFFICIENT FIXTURES AND EQUIPMENT

ON SITE ALTERNATIVE WATER SOURCE

RAINWATER COLLECTION SYSTEM

SUB-METERING OF WATER SUPPY SYSTEM

OTHER RELATED CODES

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JAKARTA GREEN BUILDING USER GUIDE

VOL. 5

WATER EFFICIENCY

D E S I G N P R I N C I P L E S

C A S E S T U D Y

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03

Filter

Storage System

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APPENDIX

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Water is an essential resource for life and good health, but about a third

of the global population does not have access to clean water to meet its

daily needs. Although a large portion of our planet contains water, most

of it is salty and thus not consumable. Freshwater comprises only 2.5% of the total water on earth, 70% of which is locked in glaciers and permanent snow cover. This limited sources combined with

massive global demand of fresh water has led to global water scarcity.

The situation is getting worse as needs for water rise along with

population growth, urbanization, urbanization and increases in

household and industrial uses.

Almost one fifth of the world’s population (about 1.2 billion people)

lives in areas with water scarcity. Water scarcity can occur even in

areas with plenty of rainfall or freshwater, if it is not well protected,

used and distributed.

1 Water Resources Institute. (http://www.scienceforums.com)

Global Water Distribution1

F I G U R E . 0 1

0.9%Others (Incl. soil soisture, swamp water, and permafrost)

68.9%Glaciers & Permanent Snow Cover

Out of 100% Global Water in the world, 97.5% of it is unconsumable Salt Water, and oly 2.5% is Freshwater.

29.9%Ground Water

0.3%Freshwater Lakes & River Storage (Only this portion is renewable)

Water Efficiency:An Introduction

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Although Jakarta’s 2010 published per capita water consumption of 78

litres/day3 looks quite good as compared to the average for 22 other

Asian Cities (278 litres/person/day), it does not portray the entire picture.

It represents only the total volume of water sold by the water company,

which does not serve 46% of Jakarta’s water needs. This shortfall is

mostly met by extracting ground water. An unauthorised water supply

system supplies bottled ground water to a large segment of the market.

About 70% of households depend on ground water supply.

2 World Resources Insitute’s Aqueduct. (http://www.wri.org/our-work/project/aqueduct)

3 Siemens Asian Green Cities Index 2013. (http://www.siemens.com/entry/cc/en/greencityindex.htm)

4 Research report by The Asian Development Bank.2004. Water in Asian cities: Utilities’ Performance and Civil Society Views. (http://www.adb.org/sites/default/files/pub/2004/water_asian_cities.pdf)

Global Water Risk2

Jakarta’s Water Supply and Usage

(in percentage)4

F I G U R E . 0 2

F I G U R E . 0 3

Low risk (0-1)

Medium to high (2-3)

High risk (3-4)

Extremely high risk (4-5)

No Data

Low to medium (1-2)

29%Non Domestic

54%Centralized Piped Water Network

46%Ground Water

20%Domestic

51%NRW

Source: The Asian Development Bank.

W A T E R S U P P L Y I N

J A K A R T A

Annual Water Use Water Supply in Jakarta

Jakarta faces multiple challenges related to water management and

efficiency, despite having ample natural supply through rivers and rainfall.

These challenges include diminished freshwater supply, flooding and land

subsidence due to excessive groundwater exploitation.

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Moreover Jakarta loses an estimated 50% of its water supply to

leakage5, one of the highest rates in Asia.

Jakarta is blessed with 13 rivers that could potentially be used for its

water needs. Unfortunately, these rivers get heavily polluted after

entering the city and are not usable for raw water supply. Cleaning up

the rivers and diverting sources of their pollution could provide a viable

source for the city’s growing water needs. According to a 2011 report

by Jakarta Environmental Management Agency (BPLHD), 71% of the

city’s river water is heavily polluted, 20% is partly polluted, and 9% is

lightly polluted.

Piped water supply in Jakarta is characterised by poor levels of access

and quality. Reliability, limited coverage of the piped network, the

low cost of groundwater, and water quality are important factors in

determining consumer preference for groundwater. This preference for

groundwater has led to excessive groundwater use and theft, which is

causing significant land subsidence, pollution and salinization of aquifers

and increased levels of flooding.7

5 Based on source water lost through network.6 The World Bank.7 Law, Environment and Development Journal LEAD Journal, Volume5/L, at www.lead-journal.org

Jakarta Rivers Before and After Entering the City6

F I G U R E . 0 4

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Jakarta experienced floods in 1996, 2002, 2007, and 2013 with

devastating consequences on human life and the socio-economic

conditions. The 2007 flood inundated more than 70% of the city and sent

about 450,000 fleeing their homes. Expenditure in flood control in the

period 1995 - 2001 amounted to about IDR 239 billion (USD 23 million).8

Groundwater extraction in Jakarta significantly exceeds groundwater

recharge, leading to a falling groundwater table and increased land

subsidence. Land subsidence was first identified when cracks were

discovered in the Sarinah bridge in 1978. Within the past 20 years, land

has subsided up to 57 cm in North Jakarta and 28 cm in South Jakarta.

With the alarming average subsidence rate of 10 cm/year, combined with

rising sea water level, it is predicted that roughly 32.5% of Jakarta area

will be under the sea in 2050, displacing millions of people and rendering

most of the north Jakarta area uninhabitable (see Figure 6).

Numerous reasons for the increased flooding have been put forward,

including:

• Drastic reduction in green open spaces resulting in increased water

runoff and sedimentation in rivers. The reduced infiltration is also

primarily responsible for the depleted groundwater table.

• Lack of an adequate garbage disposal system, resulting in pollution

and choking of rivers.

Flooding in Jakarta in 2012-20139

F I G U R E . 0 5

F L O O D I N G & F R E S H W A T E R

L O S S

G R O U N D W A T E R O V E R -

E X P L O I T A T I O N A N D L A N D

S U B S I D E N C E

8 Law, Environment and Development Journal LEAD Journal, Volume5/L, at www.lead-journal.org8 The World Bank.

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Jakarta Topography Condition Prediction

by 205010

F I G U R E . 0 6

Below average sea level

2000Around 5.1% of Jakarta Capital City area is under the average sea level.



2025Around 20.5% of Jakarta Capital City area will be under the average sea level.

2025Around 32.5% of Jakarta Capital City area will be under the average sea level.

Above average sea level

Unfortunately, most of the high density buildings requiring deep

groundwater supply are located in the critical zones for groundwater.

This highlights the importance of reducing water consumption in

buildings and using reclaimed and alternate water sources to minimize

the negative ecological impacts.

Deep Groundwater Condition in Jakarta in 200310

F I G U R E . 0 7

Critical Zone

Danger Zone

Alert Zone

10 Firdaus, Indonesia Water Institute-2013.

With the assumption of constant subsidience rate from 2000 to 2050 and the sea level rise is 6 mm/year

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Shallow Groundwater Condition in Jakarta in 200210

F I G U R E . 0 8

Critical Zone

Danger Zone

Alert Zone

It is clear the water problems in Jakarta needed to be addressed by an

integrated approach of appropriate utilization & management of surface

water, ground water & rain, waste treated water.

This code attempts to address the water related challenges in Jakarta by:

• Reducing the demand for municipal and ground water (through

efficient fixtures, rainwater harvesting and recycling).

• Reducing the runoff (through rainwater collection and absorption

wells).

10 Firdaus, Indonesia Water Institute-2013.

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Faucets/fittings should not exceed the maximum flow rates and flush

capacities listed below.

Recycled water from Sewage Treatment Plant should be used for

secondary water consumption.

Air conditioning condensate harvesting should be used for secondary

water consumption.

Landscape irrigation should use water sources other than groundwater

and municipal water supply (PDAM).

The applications of alternative water sources and its usages should

follow the schematic diagram in Figure 9.

All faucets/fittings should have pressure range from 0.5 to 5.5 bars.

(1)

(1)

(2)

(3)

01 code requirement

C O D E R E Q U I R E M E N T 1Water Efficient Fixtures and Equipment

C O D E R E Q U I R E M E N T 2On site Alternative Water Source

A R T I C L E1 5

A R T I C L E1 7

P R O D U C T S / F I T T I N G S Maximum Flow Rate/Flush Capacity Requirements

Shower Taps & Mixers

Basin Taps & Mixers

Sink/Bip Taps & Mixers

Showerheads

Flushing Cisterns (per Flush)

Urinals & Urinals Flush Valve

(per Flush)

9 litres/min

6 litres/min

8 litres/min

9 litres/min

Dual flush 4.5 litres (full flush)

1.5 litres

Water Fixure Flow Rate/Flush Capacity RequirementsT A B L E . 0 1

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Alternatively, instead of having air condensate for graywater system,

it can be connected to the rainwater collection pipes to further reduce

consumption from PDAM and deep groundwater source.

Schematic Diagram of Clean and Recycled Water

System (Alternate 1)

Schematic Diagram of Clean and Recycled Water

System (Alternate 2)

Schematic Diagram of Recycled Water Use

roof rainwater collection

roof rainwater collection

condensate water

condensate water

floor drain, basin

floor drain, basin

WC

WC

condensate water

condensate water

floor drain, basin

floor drain, basin

WC

WC

condensate water

condensate water

ground rainwater collection

ground rainwater collection

floor drain, basin

floor drain, basin

STP

STP

WTP

WTP

solid waste (handled by IPLT)

solid waste (handled by IPLT)

PDAM

PDAM

ground water(if apply)

ground water(if apply)

filter

filter

filter STP

solid waste

collection point

WC

WC

F I G U R E . 0 9

F I G U R E . 1 0

F I G U R E . 1 1

water collection

water collection

raw water storage

raw water storage

absorbtion well/pool

absorbtion well/pool

city drainage

city drainage

clean water storage

clean water storage

treated water storage


clean water


(if out of cappacity)

(if out of cappacity)

recycled water consumption


clean water consumption


grey w

ater

black w

ater

(if applicable)

(for area with high permeability

soil)

(for area with high permeability

soil)

surface irrigation

hand basin

shower bath

clothes washer

cooling towertoilets

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Rainwater collection system needs to be provided. The volume of the

rainwater collection system (in m3) shall be 0.05 m (zero point zero five

meter) X ground floor area (in m2).

Absorption wells and absorption pools should be provided as per

Governor Regulation No 20, 2013 on “Absorption Well”, shown in the

following table.

Planning should include planning for placement of measuring tools for

water consumption (water sub-meter) at the following locations:

a. water consumption system from the City Owned Water Supply

Company and/or ground water;

b. water consumption recycling system; and

c. other additional water supply system in the event the two above-

mentioned systems are insufficient.

Increase the size of the rainwater collection system as per the

description below, instead of providing absorption wells and pools in

locations where:

a. Depth of surface of ground water is ≤ 1.5 m (one point five meters) in

wet season; and/or

b. Soil with water permeability < 2cm/hour (two centimeters per hour).

The rainwater collection system planning scheme shall follow the chart

as contained in Figure 9 or Figure 10 above.

(1)

(2)

(2)

(1)

(2)

C O D E R E Q U I R E M E N T 3Rainwater Collection System

C O D E R E Q U I R E M E N T 4Sub-metering of Water Supply Systems

A R T I C L E2 2

A R T I C L E1 6

A R T I C L E2 3

B U I L D I N G C O V E R A G E(m2)

V O L U M E(m3)

50

51 - 99

100 - 149

150 - 199

200 - 299

300 - 399

400 - 499

500 - 599

600 - 699

700 - 799

800 - 899

900 - 999

2

4

6

8

12

16

20

24

28

32

36

40

Volume of Absorption Well Based on Building

Coverage

T A B L E . 0 2

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(1)

(2)

(3)

(4)

A P P L I C A B L E S T A N D A R D SOther Related Codes

To meet the requirements, at least 4 sub meters should be installed

following the schematic diagrams shown in Figure 12 below:

A more elaborated water metering system for better water

management and efficiency is discussed in the Design Principles

section of this guideline.

Demand Management, Sub-metering of Water Supply Systems,

Groundwater Extraction Control (Governor Regulation Number 156

Year 2010 on Energy and Water Saving).

Rainwater Harvesting System and Zero Run Off Policy (Governor

Regulation Number 20 Year 2013 on Infiltration Well).

SNI 03-6481 concerning Plumbing System.

SNI 03-7065-2005 concerning Plumbing System Design Guideline.

Schematic Diagram ofSub-metering System

F I G U R E . 1 2

PDAM

PDAM

rainwater

rainwater

ground water

ground water

black & grey water

black & grey water

condensate water

condensate water

water collection

water collection

raw water storage

raw water storage

water storage

water storage

clean water storage

clean water storage





WTP

WTP

STP

STP

filter

filter

M

M

M

M

M

M

M

M

M

water meter

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02 design principles

Understanding water utilization patterns in buildings is important to develop efficient system and effective water management strategies. The charts below show typical water use break down in typical commercial and instutitional facilities in Singapore. The patterns in Jakarta are expected to be fairly similar to these.

Typical Water Use Breakup in Singapore11

F I G U R E . 1 3

Schools

Commercial Office Buildings

Government Office Buildings

Hotels

Toilet

General washing & irrigation

Laundry

General washing & other amenities

Staff/worker

Restaurant

Irrigation

Swimming pool

Guest room

Toilet & pantry usage

Cooling system

53.1%

0.3%

31.0%

28.0%

4.0%37.0%

39.0%12.0%

5.0%1.0%2.0%3.0%

4.0%

34.0%

51.0%

8.0%

41.0%

46.6%

11 Singapore PUB (Public Utilities Board). The National Water Agency of Singapore. 2011. Water Efficient Building Design Guide Book. Singapore: Stallion Press.

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As Figure 13 shows, most water is used for non-potable purposes,

regardless of building types. This indicates a huge water saving

opportunity through reclaimed water system, rain water harvesting and

air conditioning condensate, which are suitable for non-potable uses such

as irrigation, general washing and cooling system.

Using rain water and air conditioning condesate as alternative water

source is particularly interesting as Jakarta is characterized by tropical

climate with relatively high rainfall and relative humidity.

Significant water saving can also be obtained through the utilization of

water efficient fixtures. As indicated in Table 3 below, installing efficient

fixtures and faucets in these areas can lead to substantial water saving.

Reducing water consumption from primary sources (e.g. PAM and deep

well) has multiple benefits. Due to increasing demand and diminishing

supply, cost of water supply is increasing. Any reduction in consumption

directly reduces the building’s water supply costs and wastewater

disposal charges. It can also reduce associated energy costs, such as

treatment, pumping and water heating. Building’s water supply, cleaning

and storage system can also be reduced in size, thus saving capital costs.

Some of the most effective ways of reducing potable water consumption

in buildings are:

1. Efficient Fixtures

2. Sub-metering of all major water consuming systems

3. Grey water reuse

4. Cooling tower water efficiency

5. Condensate water harvesting

6. Rainwater Collection

Areas of Main Improvement Potential12

T A B L E . 0 3

B U I L D I N G T Y P E

Areas with Main Improvement Potential

Toilet KitchenSinks LandscapingShower Heating/CoolingLaundry Pools Streril-

lizationResidential

Hotels

Hospitals

Schools

Offices

Shopping Centres

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

12 Arab Forum for Environment and Development (AFED). 2011. Water Efficiency Handbook, Second Edition.

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E F F I C I E N T F I X T U R E S

Water efficient fixtures are now widely available. Reduction in water

consumption directly reduces the building’s water supply costs and

wastewater disposal charges. For example, 62% reduction in water

usage was achieved at a rest stop that was equipped with ultra-

low-flow toilets and waterless urinals.13 Table 4 below outlines the

recommended maximum flow rate or flush capacity to further reduce

water consumption.

Analysis for various building types in Jakarta has shown savings in

water consumption between 8% and 39% through the use of water

efficient fixtures.

13 American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE). 2006. ASHRAE green guide: The Design, Construction, and Operation of Sustainable Buildings. USA.

14 IFC analysis for Jakarta.

Typical Efficient FixtureT A B L E . 0 4

P R O D U C T S /F I T T I N G S

Maximum Flow Rate/Flush Capacity

Requirement Recommended

Shower Taps & Mixers

Basin taps & mixers

Showerheads

Sink/Bip Taps & mixers

Flushing cisterns

Urinals & urinals flush valve

9 litres/min

6 litres/min

9 litres/min

8 litres/min

4.5 litres (full flush)

1.5 litres

7 litres/min

4 litres/min

7 litres/min

6 litres/min

4 litres (full flush)

1 litres

Potential Saving by Using Water Efficient Fixtures14

F I G U R E . 1 4

5 2515 35 450 2010 30 40

School

Hospital

Office

Apartment

Retail

Hotel

Percentage Reduction in Fresh Water Consumption

35

39

14

24

25

8

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13 The Renovator’s Supply, Inc. How a Dual Flush Toilet is Better than Standard Toilet. (http://www.rensup.com/blog/post/dual-flush-toilets)

Efficiency Using Dual Flush System15

F I G U R E . 1 5

160

140

120

100

80

60

40

20

018.9

litre/flush7.6

litre/flush11.4

litre/flush3.8

litre/flush3.8

litre/flush

Among all the water consuming fixtures in typical commercial and

residential buildings, toilet flushes consume the most amount of potable

water. In some cases, this can add up to 75% of the total water use in

the building. Efficient dual flush systems that use only about 4.5 liters

for a full flush and 3 liters for a half flush, this consumption can be cut

down significantly.

Washing hands and ablution can use up a lot of water in typical

Jakarta buildings. Faucets using up to 23 liters/min are still used in some

buildings, even though efficient faucets that use as little as 7 liters/min

are available. Lower flow rates are possible if the faucets are fitted with

tap aerators. A study done by Singapore Public Utilities Board (PUB)

indicates that flow rates as low as 2 liters per minute may be sufficient

for normal washing purposes in toilets.

Water Efficient Showerhead. A normal showerhead has a flow rate of

up to approximately 12 liters/min. A water efficient showerhead helps to

reduce the water usage without affecting the comfort level of the water

pressure for users.

Flushing of urinals can use a lot of water as well, according to an

estimate up to 20% of the total in a typical commercial building.

Waterless urinals completely eliminate water use in urinals using a one

way valve and a cartridge that prevents backflow and odors. For urinals

that use water, it is recommended to specify them with 1 Litre/flush

or less.

W A T E R E F F I C I E N T F L U S H I N G

S Y S T E M

W A T E R E F F I C I E N T

F I X T U R E

Water Consumption of Typical Toilet Flush System (m3/year)

Single Flush

Dual Flush

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S U B - M E T E R I N G O F A L L M A J O R W A T E R C O N S U M I N G S Y S T E M S

A very important strategy in water management is monitoring

consumption using sub-meters. While metering does not save any

water directly, it has an indirect impact of increasing user awareness of

consumption. Accurately measuring water use can help facility managers

identify areas for targeted reductions and to track progress from water-

efficiency upgrades. Submeters can also help identify leaks and indicate

when equipment is malfunctioning.

Although the code regulates having sub-meters only for the supply

stream if multiple water sources are used, it is recommended to have

sub-meter for the water consuming systems. Metering and recording

water consuming systems assist the building manager in isolating over

consumption and leakage problems in each consuming system. For

example, installation of sub metering system in University of California,

Berkeley campus buildings in USA revealed that 71% of the water

fixtures used 7.6 - 15 liter/flush, more than the rated 6 liter/ flush.

This indicated leakages in the system, and fixing the problem led to

significant water savings.17

An Example of Water Consumption Chart16

F I G U R E . 1 6

1200

1100

1000

900

800

700

600

500

1 5 93 7 112 6 104 8 12

October (2008)

This sudden peak may indicate a leak in the piping system

16 Singapore PUB (Public Utilities Board). The National Water Agency of Singapore. 2011. Water Efficient Building Design Guide Book. Singapore: Stallion Press.

17 The Green Initiative Fund. University of California, Berkeley. Water Metering and Sub-Metering of UC Campus Buildings. (http://tgif.berkeley.edu/index.php/funded-projects/projectstatuses/61-watermetering)

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Simple Grey Water Treatment Proses

F I G U R E . 1 8

A Schematic Diagram of the Locations tf Water Meters

Being Installed in Singapore

F I G U R E . 1 7

Source: The Renovator’s Supply, Inc. How a Dual Flush Toilet is Better than Standard Toilet (http://www.rensup.com/blog/post/dual-flush-toilets)

Fire Fighting System

Potable

Hosereel System

East Wiring Cooling TowerPotable

Water

NEWater

Cafetaria/Childcare

Flush Valve System

Landscape

Potable Water

Cooling Tower

M

M

M

M

M

M

M

M

M

M water meter

G R E Y W A T E R R E U S E

In commercial settings where bath, dish, and laundry water is available,

grey water reclamation after solid waste removal can provide a reasonable

payback of investment. The reclaimed greywater can be used for

applications such as toilet flushing, condenser water, and site irrigation.

Greywater is typically not suitable for use as potable drinking water.

Greywater use for irrigation and HVAC condensing water should be

carefully evaluated as harmful chemicals can be used to treat the

reclaimed water.

sewer

collection point

treated water

storage

grey w

ater black w

ater

(if applicable)

(overflow)

surface irrigation

hand basin

shower bath

clothes washer

cooling towertoilets

AQUACELL UNIT

Aero

bic

Screen

ing

Ultrastratio

n

Bio

log

ical T

reatmen

t

Ultravio

let D

isinfectan

t

Ch

lorin

e R

esidu

al P

rotectio

n

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Plaza Indonesia Reclaimed Used Water System18

Toilet with Greywater System

F I G U R E . 1 9

F I G U R E . 2 0

Greywater systems require significant design effort and initial cost, and

also bring the risk of contamination and pollution if mismanaged. Running

costs for more complex systems can be high, with system payback

potentially extending for many years. System maintenance and upkeep

also play important factors in choosing this water conservation method.

Filters, pumps, and treating stations all require attention. Grey water

systems are typically cost-effective in hospitality and similar buildings

with high-volume, regular non-biological contamination usage, such as

laundry plants coupled with large non-potable loads like toilet flushing and

landscaping irrigation.

Plumbing system for greywater should be clearly separated from the

blackwater system to prevent contamination.

Residential greywater systems in urban areas are typically limited to the

water from bathrooms. An innovative solution from Japan (Figure 20

below), combines the wash basins with the water cistern.

include using air handler condensate, single-pass cooling water,

rainwater, and foundation groundwater for cooling tower make-up water

and lawn irrigation. Reduced potable water use by more than 33% and

saved more than 6 million m3 of water in total since the program began

in the 1980s.19

The used water from the wash

basin is collected in the cistern

and used for toilet flushing.

University of Texas at Austin

has focused on recovering

and reusing water from onsite

alternative sources to serve non-

potable water needs. Retrofits

18 Firdaus and Indonesian Water Insittute. 2012.19 Water Sense, a US Environmental Protection Agency (EPA) program. 2012.

Watersense at Work: Best Management Practice for Commercial and Institutional Facilities Guidebook.

19

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C O O L I N G T O W E R W A T E R E F F I C I E N C Y

Cooling tower water use in commercial building located in hot and humid

climate can consume one-third to half of the total building water usage.

Some cooling towers can use greywater (and other kinds of recycled

water) if certain water quality criterion is met.

Two Types of Cooling Tower in term of differences in air stream

direction; Counterflow Cooling Tower (left) and Crossflow

Cooling Tower (Right)20

Two Types of Cooling Tower in term of the differences in

refrigeration circuit; Closed or indirect Cooling Tower (left) and open or dirrect cooling

tower (Right)21

F I G U R E . 2 1

F I G U R E . 2 2

Counterflow Cooling Tower

Closed Cooling Tower

Crossflow Cooling Tower

Open Cooling Tower

To reduce water usage at cooling towers, the designer should focus on

the two factors that can be controlled: drift (water droplets that are carried

out of the cooling tower with the exhaust air) and blowdown (the removal

of circulating water to maintain the amount of dissolved solids and other

impurities at and acceptable level designated by the electrical conductivity

of the water). Evaporation is integral to a cooling tower performance and

cannot be reduced without an acceptable reduction in performance.

warm moist air out

warm moist air out

cold water out

dry air in

dry air in

warm moist air out

warm moist air out

cold water out

cold water out

centrifugal fancentrifugal fan

cold water out

Fill Media

Fill Media

Cold Water Basin

Cold Water Basin

Air Inlet Louvre

Hot Water Distributuon


pump

20 Waterhouse Engineered Water. Tower Design. (http://engineeredwater.us/tower_design)

21 Betterbricks Powerful Energy Ideas, Delivered by NEEA. Cooling Tower. (http://www.betterbricks.com/building-operations/cooling-towers#TypesOfCoolingTowers)

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Four Ways of Water Leaves Cooling Tower System

F I G U R E . 2 3

Drift can be reduced by baffles or drift eliminators. Reducing blowdown

to the minimum level consistent with good operating practice can

conserve significant volumes of water. Reducing blowdown is the same as

increasing the condenser water cycles of concentration, which can be done

by multitude of ways. One way of increasing the cycle of concentration

while maintaining cooling tower and chiller performance is through

incorporating good water treatment program that includes chemical dosing

and careful monitoring of water parameters.

The relative water efficiency of a cooling tower is commonly measured

by computing the cycles of concentration. To measure cycles of

concentration, divide the conductivity of sump water by the conductivity

of the entering tap water. Many systems operate at two to four cycles

of concentration, while six cycles or more might be possible. Increasing

cycles from three to six reduces cooling tower make-up water by 20

percent and cooling tower blowdown by 50 percent.

Cooling Tower Water Usage at Various

Cycles of Consentration for 100-Ton Tower22

F I G U R E . 2 4

circulated cooling water

make up water suppy

chill

er

3

4 2

1

1

3

2

4

Fill Media

Cold Water Basin

Air Inlet Louvre


Drift Loss

Evaporated Water

Blowdown

Leaks & Overflows

Cooling Tower Water Usage at Various Cycles of Concentration for 100-Ton Tower

7.500

7.000

6.500

6.000

5.500

5.000

4.500

4.000

3.500

3.000

1 53 72 64 8 9

Cycles of Concentration

Gal

lon

s p

er D

ay

22 EPA Water Sense. 2012. Best Management Practice for Commercial and Institutional Facilities.

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Percent of Make-Up Water Saved by Maximizing Cycles of Concentration23

T A B L E . 0 5

1.5

2.0

2.5

3.0

3.5

4.0

5.0

6.0

53%

30%

16%

7%

-

-

-

-

61%

42%

30%

22%

17%

13%

7%

3%

44%

17%

-

-

-

-

-

-

58%

38%

25%

17%

11%

6%

-

-

63%

44%

33%

25%

20%

16%

10%

6%

33%

-

-

-

-

-

-

-

56%

33%

20%

11%

5%

-

-

-

62%

43%

31%

24%

18%

14%

9%

5%

50%

25%

10%

-

-

-

-

-

60%

40%

28%

20%

14%

10%

4%

-

64%

45%

34%

26%

21%

17%

11%

7%

N E W C O N C E N T R A T I O N R A T I O (CRf)

IN

IT

IA

L C

ON

CE

NT

RA

TI

ON

R

AT

IO

(C

n)

3.5 7.02.5 5.0 9.02.0 4.0 8.03.0 6.0 10.0

These subtle improvements and modifications to the condenser water

system should be incorporated into the installation at the design level

to save significant amounts of water from the onset and provide an

efficient system. Minimizing the condenser water loss, ensuring proper

water treatment, and constant system service will save valuable

amounts of water.

The 1500 m2 Environmental Science Centre in Fort Meade, Maryland,

saved about 2,000 m3 of water and approximately $1,800 by reducing its

cooling tower blowdown.24

In Australia, water efficiency of cooling tower is done by:

• Correct assembly of float valves.

• Install meter conductivity and blow-down automation system at

conductivity level which has been determined in the water which will

be recirculated.

• Implement “performance-based” maintanance.

• Reduce heat load by increasing building energy efficiency.

• Increase whole air conditioning efficiency by system upgrading or

waste water treatment.

Additional Reference :The Australian Institute

of Refrigeration, Air Conditioning and Heating,

Best Practise Guidelines. Water Conservation in

Cooling Towers(http://www.airah.org.au/

imis15_prod/content_files/bestpracticeguides/bpg_

cooling_towers.pdf)

23 Water Sense, a US Environmental Protection Agency (EPA) program. 2012. Watersense at Work: Best Management Practice for Commercial and Institutional Facilities Guidebook.

24 US Environmental Protection Agency. Top 10 Water Management Techniques. (http://www.epa.gov/oaintrnt/water/techniques.htm)

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C O N D E N S A T E W A T E R H A R V E S T I N G

In some airconditioning systems, it is feasible to collect condensate water

for uses such as irrigation, cooling tower make up, and toilet flushing.

In hot-humid climates, condensate from air conditioning can be a good

source of clean, cold water that is well-suited for reuse.

The volume of condensate generated depends upon the cooling load,

local temperature and humidity, make-up air volumes, and target indoor

temperature and humidity. As a rule of thumb, 0.1 to 0.3 gallons/hour of

condensate water can be generated per ton of cooling25. In hot-humid

climates, peak condensate production during summer months can be

assumed to be approximately 0.5 to 0.6 gph/1000 ft2 or 1.9 to 2.27

l/h/93m2 of cooled area.

Rice University in USA captures condensate water from many of its

buildings for use in the central plant’s cooling towers as make up water.

This systems is estimated to save at least 45.4 million liters of water per

year, which is equivalent to about 5 to 6% of Rice University’s annual

water consumption.

Schematic Diagram of Condesate Water for

Makeup Cooling Tower26

F I G U R E . 2 5

25 Guz, Karen. 2005. Condensate Water Recovery. Publised in ASHRAE Journal. (Vol 47, No. 6, June 2005).

26 Lucina and Sekhar, 2012. Energy and water conservation from AHU in hot and humid climate. Energy and Building Journal volume 45.

make up water suppy

make up water suppy

evaporation

COOLING TOWER

COOLING TOWER

AHU

CAP AHU

coo

ling

co

il

pre

-co

olin

g

coil

AHUAHU AHU

evaporation

Fill Media

Cold Water Basin

Air Inlet Louvre


con

den

ser

con

den

ser

warm water

warm water

blowdown

blowdown

condensate

con

den

sate

wat

er f

rom

oth

er A

HU

s

condensate pump

pumpcondensatecollector

condensatecollector

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United World College (UWC) South East Asia - East Campus, Singapore,

harvested about 1400m3 of condensate water in the first 5 months

(August - December) of operation. The harvested condensate water

reduces potable water consumption for cooling tower make-up while also

reducing the temperature of condenser water for the HVAC.

The G+20 Floor building’s HVAC system consisting fresh air handling

units typically can produce 2600 liters condensate water in 24 hrs and

78000 liters in a month at an average summer outdoor conditions, which

can be utilized trim down the demand of potable water and saving a

substantial amount of energy and carbon emissions.27

27 Khan, Shahid Ali. 2013. Conservation of Potable Water Using Chilled Water Condensate from Air Conditioning Machines in Hot&Humid Climate. Published in International Journal of Enggineering and Innovative Technology Volume 3, Issue 2.

28 UN. Habitat. Blue Drop Series on Rainwater Harvesting and utilization-Book 2: Beneficiaries and Capacity Building. (http://www.unwac.org/new_unwac/pdf/WATSAN_Normative_Pubs/Blue_Drop_Series_02_-_Capacity_Building.pdf)

29 UN. Habitat. Blue Drop Series on Rainwater Harvesting and utilization - Book 2: Beneficiaries and Capacity Building. (http://www.unwac.org/new_unwac/pdf/WATSAN_Normative_Pubs/Blue_Drop_Series_02_-_Capacity_Building.pdf)

R A I N W A T E R H A R V E S T I N G

Jakarta on an average gets about 1800 mm of rainfall annually, most of it

between November and April. For a roof area of 30 m2, a 5.5 m3 capacity

tank can provide daily reclaimed water supply of about 60 liters. This

highlights the potential of water saving through rain water harvesting.28

Rainwater harvesting can be implemented by collecting water at the

roof (roof catchment), or at the ground (ground catchment). The stored

rainwater can be used for laundry, toilet and urinal flushing, car washing,

and ornamental water features. It can even be used for cooling tower

make-up. The benefit of rain water harvesting is two fold. Firstly, it

reduces the expense of municipal supply or ground water extraction.

Secondly, it also reduces water run off to the city sewage and drainage

system thus mitigating Jakarta’s perennial flooding problems.

Average Rainfall Data for Jakarta29

F I G U R E . 2 6

Precipitation (mm)

Average Rainfall Days

125

100

75

50

25

0

JanuaryM

ay

September

March July

November

February

June

October

April

August

Decem

ber

Per

cip

itat

ion

(m

m)

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Roof Footprint Roof FootprintRoof Footprint

Roof Footprint Roof Footprint Roof Footprint

Figure 27 below outlines possible rainwater utilization based on

commercial building types and catchment areas.

Suitability of Commercial Rainwater Use30

Roof Footprint31

F I G U R E . 2 7

F I G U R E . 2 8

The size of the catchment area or roof will determine how much

rainwater that you can harvest. The area is based on the “footprint” of

the roof, which can be calculated by finding the area of the building and

adding the area of the roof’s overhang.

Equation below provides a calculation for rainwater capture potential.

Conversion factor of 0.623 is included to take into account capture

efficiency because some of the rainwater is lost through evaporation,

splashing, or other means.

C A T C H M E N T A R E A

30 Davidson, Guenter Hauber; Water Conservation Group. Supplementing Urban Water Supplies Through Industrial and Commercial Rainwater Harvesting Schemes. (http://www.watergroup.com.au/download/P_RWH-integrUrbWatSuplyGHDv1a070308.pdf)

31 Texas A & M Agrilife Extension. Rainwater Harvesting, Catchment Area. (http://rainwaterharvesting.tamu.edu/catchment-area/)

Possible

Not recommended

Acceptable

R A I N W A T E R(Roof Only)

S T O R M W A T E R(Roof & Ground)

Amenities/BathroomKitchen/Food PreparationHot Water SystemToilet FlushingLaundryIrrigationVehicle WashingCooling TowerPool Top-up WaterOther Process Water

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Channels all around the edge of a sloping roof to collect and transport

rainwater to the storage tank. The size of the gutter should be according

to the flow during the highest intensity rain. It is advisable to make them

10 to 15 per cent oversized. As a rule of thumb, one square inch (6.4 cm2)

of downspout area should be provided for every 100 square feet (9.29 m2)

of roof area.

A first flush device is a valve that ensures that runoff from the first spell

of rain is flushed out and does not enter the system. This needs to be

done since the first spell of rain carries a relatively larger amount of

pollutants from the air and catchment surface.

Storage system is used to store rainwater for later uses. It is one of

the most critical, and typically the most expensive component of the

rainwater system. Rainwater storage tank could be made of concrete,

wood, metal, clay or plastic.

The filter is used to remove suspended pollutants from rainwater

collected over roof. A filter unit is a chamber filled with filtering media

such as fibre, coarse sand and gravel layers to remove debris and dirt

from water before it enters the storage tank or recharges structure.

Charcoal can be added for additional filtration. Filter chamber can be

made manually and commercial filters are widely available.

Further discussions on filters can be found on the web such as: • Rainwater Harvesting Org. Components of A Rainwater Harvesting

System. (http://www.rainwaterharvesting.org/Urban/Components.htm)

• Freerain. Commercial Rainwater Harvesting Systems. (http://www.freerain.co.uk/commercial-rainwater-harvesting-systems.html)

For example, with an annual average of 1800 mm rainfall in Jakarta, a

catchment area (e.g. roof) of 5,000 m2, could harvest 1.8 m x 5,000 m2 x

0.623 = 5,607 m3 of rain water annually or equal to an average of 15.36 m2

per day.

To avoid water pollution, walls, roofs and gutters should not use asbestos

or toxic paints.

G U T T E R

F I R S T F L U S H I N G

S T O R A G E S Y S T E M

F I L T E R

Harvested water (m3) = average rainfall depth (m) x catchment area (m2) x 0.623 conversion32

32 Texas A & M Agrilife Extension. Rainwater Harvesting, Catchment Area. (http://rainwaterharvesting.tamu.edu/catchment-area/)

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Pumping Station

Supply

Pipe

Tank

Storage tank must be opaque and painted to inhibit algae growth, must be

covered and vents screened, and must be accessible for cleaning (if used

for potable system). The storage tank needs to be placed as close to the

catchment area as possible and the size determined by calculations based

on the demand, frequency of rainfall, surface area, budget and aesthetics.

Some of the elements of a typical rainwater harvesting system are

highlighted in the figure below.

Singapore offers interesting case studies of rainwater harvesting. Because

of low supply and high demand, country’s regulations have a strong

emphasis on rainwater collection. About 84% of the population lives in

high rise apartments. These buildings are required to collect rainwater in

cisterns on the roof. A recent study demonstrated an effective saving of

4% of the water used, the volume of which did not have to be pumped

from the ground floor. As a result of savings in terms of water, energy

costs, and deferred capital, the cost of collected roof water was calculated

to be S$0.96 against the previous cost of S$ 1.17 per cubic meter.

Rainwater Harvesting System for Reuse33

F I G U R E . 2 9

Rainwater Harvesting System at Changi

Airport, Singapore34

F I G U R E . 3 0

33 Toronto and Region Conservation, 2010. Performance Evaluation of Rainwater harvesting Systems. (http://sustainabletechnologies.ca/wp/wp-content/uploads/2013/01/FINAL-RWH-2011_EDIT3.pdf)

34 Rainwaterharvesting.org. Rainwater Harvesting in Singapore. (http://www.rainwaterharvesting.org/international/singapore.htm)

1

3

2

1

3

5

2

4

Collection System/Catchment Area (Such as roof)

Conveyance System (Infratructure that transport the water)

Storage System (Above & below ground cistern) Wrapped in geotextile & impremeable liner

Gutter around the building roof

Smart Pre-filter & First Flush

4

5 overflow to discharge

FOR USEtank access to raw water storage

Inlet Seal

Floating Intake

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Singapore’s Changi airport collects rain falling on the runways and the

landscaped areas in two reservoirs, that are used for toilet flushing

and fire fighter drills. This amounts to about 30% municipal water

consumption savings equivalent to about S$ 390,000 per annum.35

A B S O R P T I O N W E L L

Absorption wells are intended to capture, store and recharge

groundwater, while at the same time reduce runoff to the city drainage

system. Absorbtion system is applied to areas that have typically

sandy soils with acceptable permeability rates and with ground water

level below 1.5 m. However, many parts some parts of Jakarta are not

suitable for the application of absorption well. Therefore, results of soil

investigation should be examined before applying absorption well.

Asoprtion system for unconfined aquifer (air tanah dangkal) can be

implemented using apsorption pit (Lubang Resapan Biopori) or shallow

absortion well, while deep apsorption well utilizing injection system can

be used for confined aquifers.

Biopori (left) and Shallow Absorption Well (right)36

F I G U R E . 3 1

35 United Nations Environment Programme, Division of Technology, Industry and Economics. Rainwater Harvesting and Utilization, An Environmentally Sound Approach for Sustainable Urban Water Management: An Introductory Guide for Decision-Makers. (http://www.unep.or.jp/ietc/publications/urban/urbanenv-2/9.asp)

36 Peraturan Menteri Pekerjaan Umum No. 6 tahun 2011 tentang Pedoman Penggunaan Sumber Daya Air.

control pit

absorbtion well

10 - 30 mm

80 -

100

cm

The depth of the well depend on ground water level

gutter

to s

ewer

filter

organic material

COMPOSTING

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Deep Absorbtion Well37

Bioretention System

F I G U R E . 3 2

F I G U R E . 3 3

Pipe

Sand

Gravel

Cement

Clay

Filter

control pit

gutter

absorption well

to s

ewer

from filter

concrete floor

filter

Bio retention systems treat stormwater by filtering runoff through planted

vegetation and percolating (drip feeding) the runoff through a filter

media, such as loamy sand. As the water is percolated through the soil,

pollutants are captured by fine filtration, absorption and biological uptake.

Excess water can be collected by under drain system and discharge to

the storm sewer system or directly into receiving water. Bio infiltration

systems typically are designed to store and treat run off from relatively

small storms. It should be located at least 3 metres away from buildings

to ensure water does not drain into the foundations.

B I O R E T E N T I O N

S Y S T E M S

37 Forum Teknik Sipil dan Arsitektur. Pemanfaatan Air hujan. (http://www.ilmutekniksipil.com/rekayasa-sumber-daya-air/pemanfaatan-air-hujan)

38 An Article about Bioretention System by Riversands. (http://www.riversands.com.au/bioretention-system.php)

Filter Media (sandy loam)

Transition Layer (course sand)

Drainage Layer (course sand/gravel)

Perforated Collection PipePossible Impervious Liner

0,2-0,5 m

1-3 m

0,1 m

0,15-0,2 m

0,3-0,7 m

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A rain garden is a simple form of a bio-infiltration system, that is built in

shallow depressions or low-lying areas, with a planted or stone-covered

bed that is specifically designed to capture and absorb stormwater and

allow it to be slowly absorbed into the soil.

Rain gardens are suitable for sites that are sandy, gravellly, loam, or

a mix with up to 10 per-cent clay.Sites with mostly clay soil are not

suitable. The soil sould be permeable to depth of between 0.6-1.2 m

below the rain garden. The surface of depression should be at least 1 m

above seasonally high shallow groundwater. The rain garden also need

to be as level as posible, to ensure that water does not run over the

lower edge. If possible, slope greater than 12 percent should be avoided.

The placement of the rain garden could be at a low point or at a location

somewhere along the natural flow path.

Rain Garden Variation39

F I G U R E . 3 4

a) Planted with shrubs, tall grasses, ferns, and perennials.

b) Dry creek with pebbles, river stones, boulders, and plants.

All options over sandy to loam soil with organic matter. Infiltration bed under the surface as shown in option a) applies to all options.

c) On a slope, create a depression on the upper side and a berm on the lower side.original slope

39 An Article about Rain Gaden by Canada Mortgage and Housing Corporation. (http://www.cmhc-schl.gc.ca/en/co/grho/grho_007.cfm)

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03 case study

Saving Clean Water Cost by Processing Used WaterP L A Z A I N D O N E S I A

Management of Plaza Indonesia (PI) has responded to the clean water

crisis faced by Jakarta due to insufficient clean water supply from

public water grid system (PAM Jaya) and relatively high cost of piped

water tariff (Rp. 12,550/m3). The problems of clean water supply for PI,

which has a total area of 404,100 m2, are exacerbated due to the new

regulation restricting deep ground water extraction and increasing tax.

Pergub DKI No 37, 2009 significantly increase deep ground water tax

from Rp. 4,400/m2 to Rp. 23,333/m2. This regulation is necessary to

mitigate the serious problem of land subsidence due to over extraction

of deep ground water in Jakarta.

Following the development and existing business opportunities, PI has

recently built Keraton Residential Tower (48 floors, 88 apartment units,

50,350 m2) and The Plaza Office Tower (47 floors, 62,650 m2), which

is going to increase the need for clean water and also the amount of

liquid waste generated. The facilities need at least 2,200 m3 of clean

water per day.

PI complex consists of Plaza

Indonesia Shopping Center

(4 floors, 62,750 m2), Grand

Hyatt Jakarta Hotel (26

floors, 447 rooms, 67,000

m2), and Plaza Indonesia

Extension (6 floors, 43,300

m2) equipped with an

underground parking facility

(Basement Parking) with an

area of 108,800 m2.

Plaza Indonesia

F I G U R E . 3 5

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To cope with the high demand of clean water supply, PI management

has decided to reclaim water from its wastewater as an alternative

non-potable water source for toilet flushing, irrigation and cooling

tower. Besides environmental benefit such as reducing wastewater and

mitigating water scarcity and land subsidence issues, reclaiming water

also offers financial benefit to PI.

If the clean water is totally supplied by PAM Jaya, the cost will be at

least Rp. 10.08 billion (365 days/year x 2,200 m3/day x Rp. 12.550/m3)

annually. This figure significantly increases to Rp. 13.54 billion/year,

if 40% of the total requirement is taken from the deep groundwater.

In addition, PI must pay the cost to treat wastewater which by a

conventional system would cost at least Rp. 1.750/m3, leading to a

total cost of wastewater treatment to Rp. 1.12 billion/year (2.200 x 0.8

x 365 x Rp. 1.750/m3). Therefore, total cost for clean water supply and

wastewater treatment is estimated at least Rp. 11.2 billion/year.

By conducting a comprehensive retrofit of the wastewater treatment

systems, at least 1,500 m3 of a total of 2,200 m3 of the PI clean water

needs can be generated from the used water reclamation plant system

employing Membrane Bio Reactor technology (MBR) + Reverse

Osmosis Membrane. Total savings from reduction of clean water cost

is Rp. 2.92 billion/year plus the cost savings from wastewater treatment

at around Rp. 1.12 billion/year. So the total savings made by the

management of the PI is Rp. 4.04 billion/year. The total investment cost

to implement Sewage Treatment Plant (STP) retrofit at Plaza Indonesia

is around Rp. 15 billion with a payback period of about 3.7 years.

Sample of the Clean Water Resulted from the

Processed Wastewater with the Background of MBR Plaza Indonesia40

F I G U R E . 3 6

40 Firdaus, 2013.

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Payback Period Calculation of Used Water Recycling SystemT A B L E . 0 6

I T E MN O Consumption(m3/Day)

Waterfare(IDR/m3)

Water Cost(Million IDR/Day)

Water Cost per Year (Billion IDR)

Saving Amount(Billion IDR/Year)*

Pam Water

Deep Groundwater

Used Water Treatment Cost

Used Water Treatment Cost

Total Investment Cost of Used

Water Reclamation Plant

Payback Period (Year)

1

2

3

4

5

2,200

2,200

2,200

2,200

12,550

23,333

1,400

7,211

27,61

51,33

3,08

15,86

10,08

18,74

1,12

5,79

4,29

12,95

-

0

15.00

3,5/1,16

*) Note: Relative to the use of water resulted from the used water treatment The calculation above is based on the used water total volume of 2200 m3/day.

Water reclaim system (grey water system) in high rise buildings in Jakarta

not only provides economic benefits (savings) as discussed above, but

also mitigates the problems of water pollution and helps overcome water

deficit in the deep ground water.

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Water Saving Device and Approaches: Flush Mechanisms41

T A B L E . 0 1

appendix

F L U S H M E C H A N I S M A D V A N T A G E S D I S A D V A N T A G E S

When the handle is pulled, a piston lifts water to start a siphon, which empties the cistern into the toilet bowl. When the cistern is empty the siphon is broken and the cistern refills ready for the next flush.

Siphon MechanismWhen flush is initiated, the air valve lifted on the siphon is open; when flush is complete, the valve closed.

Drop-valve Mechanism

Siphon Mechanism

Push-button Flush, Drop-valve Mechanism

Siphon Mechanism

It may be more effective (and cheaper) to retrofit water saving devices to an existing siphon-operated mechanism than opt for a push-button, flush-valve mechanism because:• Thereislesschanceofleakage;• Afaultymechanismiseasytodetect—the

flush performance is poor;• Low-flushavailable(4.5litre);and• Lowcost.

• Retrofitavailable.• Easytofit.• Savingsofupto30%perflush.• Lowcost.

• Fastflush.• Push-buttonoperatedratherthanaleverfor

flush action.• Separatebuttonsforfullflushandshort-

better understand by user.• Allowslowerflushvolumesbygivinga

higher flow rate.• Lowcost.

• Twoflushvolumes.• Savingsupto30%perflush.• Lowcost.

• Choiceofflushvolumes(e.g.4/2.6,6/3,6/4litres maximum/minimum flush).

• Cannowberetrofittedtocisternsinstalledbefore 1999.

• Lowcost.

• Userstopstheflush(releaseslever)whenpan is clear.

• Savingsofupto30%perflush.• Lowcost.

• Compatibilitywithretrofitdevicedependson cistern design.

• Leveroperatedratherthanbuttons.Dualflush not as well understood by users as push-button flush valves.

• Occasionallyneedtoflushmorethanonceto clear the pan.

• Generally,notveryrobust.• Notalwayscleartouserhowtooperate

the device correctly, so potential for double flushing.

• Savingscanbeveryvariable.

• Valvewilleventuallyleak(whichcanbehard to detect).

• Poorinstallationcancausevalvemechanism to stick.

• Notasrobustasthesiphonmechanism.• Mayrequiremaintenancetoremove

limescale deposits.• Ifproblemsoccur,thevalvecannotbe

replaced with a siphon mechanism.

• Occasionallyneedtoflushmorethanonceto clear the pan.

• Notalwayscleartouserhowtooperatethedevice correctly.

• Poorinstallationcancausethebuttonstobe misaligned, resulting in poor flushing.

• Buttonsneedtobeclearlylabelledtoavoidconfusion and misuse.

• Notalwayscleartofirsttimeuserhowtooperate the device correctly.

• Potentialfordoubleflushing.

S I P H O N M E C H A N I S M

V A R I A B L E F L U S H

P U S H - B U T T O N F L U S H

D U A L F L U S H

I N T E R R U P T I B L E F L U S H

41 Working Together for a World Without Waste, Business Resource Efficiency Guide. Reducing Your Water Consumption. (http://www.wrap.org.uk/sites/files/wrap/WRAP_Reducing_Your_Water_Consumption_0.pdf)

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Water Saving Devices and Approaches: Other42

T A B L E . 0 2

D E V I C E / A C T I V I T Y POTENTIAL WATER SAVINGS A D V A N T A G E S D I S A D V A N T A G E S

Also referred to as cistern displacement devices—CDDs

A flexible synthetic material partitions the cistern

• Low/nocost—canbeobtained from water supplier at little or no extra cost.

• Retrofit.• Easytoinstall.

0.5 to 2 litres per flush.

Up to 30% (between 1 and 3 litres per flush).

Up to 0.5 litres per flush.

• Nowaterinletduringflushing.

• Retrofit.

• Lowcost.• Retrofit.• Easytoinstall.• Powerofflushunaffected.

• Someofthesedevicesdeteriorateovertime and should be regularly checked and replaced if necessary, otherwise water use may increase.

• Volumeadjustersshouldnotbeusedin cisterns which were installed after January 2001, as from this date, all installed cisterns use a 6-litre flush. Using a volume adjuster in these products will result in a poor flush and can induce double flushing.

• Thedelayperiodneedstobechecked.

• Needtoensureagoodseal—canbea problem where limescale builds up.

C I S T E R N V O L U M E A D J U S T E R S ( C V A ’ S )

D E L A Y E D A C T I O N I N L E T V A L V E

C I S T E R N D A M


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The Main Advantages and Disadvantages of Urinal Water Saving Devices43

T A B L E . 0 3


A single valve such as a quarter turn ball valve can be installed in the pipework supplying the washroom.

A timer and solenoid valve can be installed on the pipework connected to the urinals, so that water supplied to the cistern is shut off during periods of non use.

• Lowcost.Typically around 70% but can be higher.

Typically around 70% but can be higher.


• Retrofitavailable.• Valveremainsclosedwhen

pressure remains unchanged (i.e.when urinal is not being used).

• Lowcost.

• Onlyapplicableifworkhoursare predictable.

• Requiresstaffreliability.

• Flushingisrelatedtooccupancy of washrooms rather than use of urinal.

• Onlyapplicableifworkhours are predictable.

M A N U A L S H U T O F F

P R E S S U R E - S E N S I T I V E H Y D R A U L I C V A L V E

T I M E R A N D S O L E N O I D V A L V E

A motion sensor is placed above the urinal to detect use. This controls a solenoid valve to allow a present volume of water into the cistern per use. When the cistern is full, the auto-siphon will automatically discharge and flush the urinal.

Barrierliquidcartridge/trap—acartridgecontaining a barrier fluid is inserted into the urinal bowl. The urine passes through the oil-based barrier fluid, which forms a seat preventing urine returning.

Deodorisingpad—apadimpregnatedwith a deodorising chemical which is inserted into the urinal outlet.

Chemicalandbiological—acartridgecontaining a chemical and microbial block is fitted into the urinal bowl or through to break down urinal and biofilm.

Chemical and microbiological blocks combinedwithaone—wayvalve—theseproducts are similar to the microbial blocks described above, but with the addition of a one-way valve to seal the waste pipe from the urinal.


Can reduce water use by 90%.

• Costeffective—ataround£170 and can be operated by battery (lifetime of between 3 and 4 years) or mains electricity.

• Retrofitavailable.• Easytoinstall.

• Disposeofthebatteryashazardous waste.

• Specialisedcleaning.• Barrierfluidneedstobe

replaced regularly.• Microbialblocksdissolve

and need to be replaced regularly.

P A S S I V E I N F R A R E D ( P I R ) S E N S O R

W A T E R L E S S U R I N A L S


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The Main Advantages and Disadvantages of Urinal Water Saving DevicesT A B L E . 0 3 (continued)


Cartridge/trap inserts containing a mechanicalsiphonvalve—thispreventsurine that has passed through it from returning to the bowl.

Vented—individualtrapsarereplacedby a single running trap installed at an angle of 1:18 to allow rapid run off of urine. A low wattage fan provides air flow in the system to remove odours.



• Mechanicalvalveremovesthe need for a barrier liquid.

• Nochemicals.• Singletrapeasytoclean.• Fanusesthesamepower

as mains-powered urinal controllers.

• Notavailableforretrofit;intended for use in specifically designed urinal bowls.

• Notsuitableforretrofit.

W A T E R L E S S U R I N A L S (continued)

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DIX

Common Types of Device and Approach that are Available to Reduce Water Use through a Tap44

T A B L E . 0 4

I T E M A D V A N T A G E S D I S A D V A N T A G E S

Screwdriver/lever actuatedPrimary function is that of an isolating valve. However, the flow through the valve can be adjusted to reduce flow rate.

The tap nose contains small holes to force water out in the form of a mist or spray.

The design of the nozzle mixes air with the water under pressure. When the water exits the nozzle the air expands, increasing the apparent water flow. Tap aerators are often integrated with a flow regulator as a pressure compensating aerator (PCA).

Percussion taps/push-down tapsTo deliver flow, the user pushes down on the tap head. When the user removes their hand, the pressure generated inside forces the tap up and it automatically closes off the flow (after a delay period set of the time of installation). A delay period of between 15 and 20 second is generally suitable for hand washing.

An infrared sensor is located on the underside of the tap head. The sensor is triggered when the user places their hands under the tap head. The temperature is preset.

Relatively new, also known as ‘click’ or two stage taps. Flow rate typically between 5 and 10 litres per minute until a resistance point is reached. To open the tap any further requires additional force. Full flow setting typically between 10 and 20 litres/minute.

• Watersavingstypicallyaround50%,but dependent on end flow rate.

• Retrofitavailable.• Cheapandeasytoinstall.

• Watersavingstypicallyupto50%,butdependent on end flow rate.

• Canachievetypicalflowratesofbetween 4 and 8 litres/minute.

• Retrofitspray-tapnoseavailable.

• Watersavingstypicallyupto50%if fitted with a flow regulator, but dependent on end flow rate.

• Retrofitavailable.• Nosplashing.• Flowratereducedtobetween2and8

litres/minute.

• Retrofitavailable.• Automaticallyclosesafteruse.• Watersavingsupto50%,but

dependent on end flow rate and flow duration.


• Paybackperiodcanbeafewmonths.

• Improvedhygiene—tapdoesnotneedto be touched.

• Watersavingsupto70%,butaredependent on the end flow rate and flow duration.


• Providesuserflexibilitywherefasterfilling is sometimes required.

• Orificemayblockwithscalebuild-up.• Doesnotregulatepressure.

• Requiresmaintenancetopreventblockage.

• ThereisariskofLegionellaifthetapis not operated regularly.

• Doesnotregulatepressure.

• Noteffectiveatpressureoflessthan1bar (100kPa).

• Standardaeratorsdonotregulatepressure.

• Mechanismcanjam(hardwatercanbe a contributor).

• Delaycycleneedstobesetcorrectly.

• Retrofitnotapplicable.• Requiresenergy–mainsorbatteryto

operate.• Scaldingcanbeanissueifthe

temperature control is incorrectly set.• Ifsensorisfouledbysoap,thenwater

flow is continuous.• Coststypicallyaround£300/tap

means longer payback period.

• Fullflowsettingnotpressureregulated.

• Longerpaybackperiods(between£150and£200perunit).

I S O L A T I N G B A L L V A L V E

S P R A Y T A P

T A P A E R A T O R

S E L F - C L O S I N G T A P S

E L E C T R O N I C S E N S O R T A P

M I X E R T A P S F I T T E D W I T H A W A T E R B R A K E


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Common Types of Device and Approach that are Available to Reduce Water Use through a TapT A B L E . 0 4 (continued)

I T E M A D V A N T A G E S D I S A D V A N T A G E S

Changes in water pressure or temperature cause the thermostat element to expand or contract. This in turn moves the slide valve which alters the proportion of hot and cold water entering the TMV, thus maintaining the mixed water temperature.

Avoids long periods of running water to get the desired temperature.

Soap dispenser delivers a ball of foam/mousse.

Relatively new. They allow the user to push a button to override a default lower flow rate setting to provide a higher flow rate delivery mode. The flow rate is controlled by an integrated flow regulator.

Flow regulators are designed to maintain a constant flow independent of supply pressure. Often integral in ‘water efficient’ taps at time of purchase.

• Watertemperatureisset—useslesswater at initial draw-off.

• Onlyonetapmayberequired.• Savingscanvary.

• Useslesswateratinitialdraw-off.• Savingscanvary.

• Smallamountofsoaprequiredperevent (water saving of up to 50%).

• Whenuserrubshandstogether,foam/mousse reduces to a small volume that requires less water to rinse from hands.

• Watersavingstypically50%inwatersaving setting.

• Providesuserflexibilitywherefasterfilling is sometimes required.

• Retrofitavailable,easytofit.• Regulatesflowregardlessofpressure.• Flowregulatorscanbedesignedto

operate at different flow rates.• Lowcost.

• Longerpaybackperiodsforthemoreexpensivevalves(between£50and£200perunit).

• Capitalcostsforinstallationofheater.

• Mayrequirenewsoapdispenser.

• Notalwaysavailableasretrofit,oftenincorporated into existing tap ranges.

• Notwaterefficientintheoverridemode.

T H E R M O S T A T I C M I X E R V A L V E ( T M V )

P O I N T - O F - S O U R C E H E A T E R

F O A M S O A P

E C O - B U T T O N S

T A P F L O W R E G U L A T O R

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Common Types of Device and Approach that are Available to Reduce Water Use through a Shower45

T A B L E . 0 5

I T E M WATER SAVINGS A D V A N T A G E S D I S A D V A N T A G E S

Screwdriver/lever actuatedPrimary function is that of an isolating valve. However, the flow through the valve can be adjusted to reduce flow rate.

The aerator is fitted between the hose and the showerhead. The design of the aerator nozzle allows air to mix with the water under pressure. When the water exits the nozzle the air expands, increasing the apparent water flow. Shower aerators can be integrated with a flow regulator as a pressure compensating aerator (PCA).

The design of the showerhead mixes air with the water under pressure. When the water exits the showerhead the air expands, increasing the apparent water flow.

Changes in water pressure or temperature cause the thermostat element to expand or contract.

This in turn moves the slide valve which alters the proportion of hot and cold water entering the TMV, thus maintaining the mixed water temperature.

• Retrofitavailable.• Cheapandeasytoinstall.

• Retrofitavailable.• Flowratereducedto

between 6 and 10 litres/minute.

• Retrofitavailable.• Flowratereducedto

between 6 and 10 litres/minute.

• Watertemperatureisset—uses less water at initial draw-off.

Typically 50%, but dependent on water pressure.

Typically 50%, but dependent on end flow rate.

Typically between 50% and 70%, but dependent on end flow rate.

Variable.

• Onlyapplicableifworkhoursare predictable.

• Requiresstaffreliability.

• Noteffectiveatpressurebelow 1bar (100kPa).

• Notsuitableforusewithelectrically heated showers.

• Lowflowmaynotprovideusersatisfaction—‘coldfeet’effect.

• Standardaeratorsdonotregulate pressure.

• ThereisariskofLegionellaif the shower is not operated regularly.

• Noteffectiveatpressurebelow 1bar (100kPa).

• Lowflowmaynotprovideusersatisfaction–‘coldfeet’effect.

• Generallynotsuitableforuse with electrically heated showers.

• Retrofitnotavailable.• Longerpaybackperiodsfor

more expensive valves (up to£200perunit).

I S O L A T I N G B A L L V A L V E

S H O W E R A E R A T O R

A E R A T I N G S H O W E R H E A D

T H E R M O S T A T I C M I X E R V A L V E ( T M V )


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Common Types of Device and Approach that are Available to Reduce Water Use through a Shower

I T E M WATER SAVINGS A D V A N T A G E S D I S A D V A N T A G E S

Avoids long periods of running water to get the desired temperature.

The regulator is fitted between the hose and the showerhead.

As electromagnetic valve works with a sensor device (infrared). When the sensor is activated the shower runs for a set period of time before shutting off.

• Useslesswateratinitialdraw-off.

• Retrofitavailable,easytofit.

• Regulatesflowregardlessof pressure.

• Flowratesofbetween6and 10 litres/minute can be achieved.

• Lowcost.

• Improvedhygiene—tapdoes not need to be touched.

• Canachieveflowratesofbetween 6 and 8 litres/minute.

Variable.

Typically 50%, but dependent on end flow rate.

• Upto70%,but dependent on the end flow rate and flow duration setting.

• Canachievetypical flow rates of between 6 and 8 litres/minute.

• Capitalcostsforinstallationof heater.

• Notsuitableforusewithelectrically heated showers.

• Requiresenergy—mainsorbattery operated.

• Ifsensorisfouledbysoap then waterflow is continuous.

• Coststypicallyaround£300/tap means longer payback period.

P O I N T - O F - S O U R C E H E A T E R

S H O W E R R E G U L A T O R S

E L E C T R O M A G N E T I C ( S E N S O R ) T A P S

T A B L E . 0 5 (continued)

Mechanical timed flow control. Usually works through controlled bleed from one side of a diaphragm to the other via a pinhole and it is the length of time that water is delivered through the showerhead.

• Automaticallyclosesafteruse.

• Flowratereducedtobetween 6 and 10 litres/minute.

• Cartridgemechanismuses a groove (rather than a pinhole) to pass the water from one side of the diaphragm to the other.

• Actuatingthevalvepushesa rubber washer down the length of the groove, cleaning away any scale deposits or other build-up as it moves.

Typically up to 50%, but dependent on end flow rate.

• Thedelaycycle(‘bleed’)needs to be correctly set.

• Ifthemechanismoperatesthrough the use of a pinhole in a diaphragm, the hole can become blocked by scale build-up.

P U S H - B U T T O N S H O W E R

DINAS PENGAWASANDAN PENERTIBAN BANGUNANPEMERINTAH PROVINSI DKI JAKARTA

Jalan Taman Jati Baru No. 1 Jakarta Barat t. (62-21) 856 342f. (62-21) 856 732

www.dppb.jakarta.go.id

jakarta green building user guide vol. 5 water … · it represents only the total volume of water...

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