NATIONAL WATER SERVICES COMMISSION
MALAYSIAOn –site treatment systems designed to treat
and dispose of effluent from single premise
and/or single ownership development

On-siteSmall Sewage Treatment System

Cess pit(An old system – Obsolete)

Individual Septic Tank

Communal SepticTank(Obsolete system serving multi premises)

TYPES OF SERVICES AND APPLICATION
Type of Services

Units (PE)OFF-SITE TREATMENT
Decentralized (Multipoint)
Centralized (Regional)

8,847 (17,839,120)
82 (6,407,515)

ON-SITE TREATMENT
Individual Septic Tank

1,306,662 (6,669,142)

Communal Septic Tank (CST)

4,378 (525, 240)

Small Sewage Treatment System

24001 (240,000)

Cess Pit (Pour Flush)* Source : Malaysia Water Industry Guide 2014
Note : 1. Estimate installation of SSTS since year 2008

894,859 (4,474,293)

3

DEFINITION of septic tank based on Water Services Industry 2006 (Act 655):“ A basic form of on-site treatment facility consisting of one or morecompartments that provides treatment of sewage by means of
sedimentation and anaerobic process.”

DESIGN CAPACITY
For 5 – 30 PE(1.125 – 6.750 m3/day)

APPLICATION•Serving a single premise, withcapacity not more than 30PE•

Other treatment system shallbe provided if the design PE
more than 30PE.

LIMITATION

Limitation inproviding
primarytreatment

Treatment
performance isinconsistent tomeet therequired
standards

PERFORMANCEMEASUREMENT

Performance issubjected toretention
which isaffected byquantity ofsettled solids
which
accumulated
over timeSingle Development Up To 30
Units Or 150PE In Total••

Septic tanks regarded as
temporary treatment system
Owner of system shall provide
the following•
150mm by-pass pipe fromlast inspection chamberbefore septic tank•By pass pipe extended it
to the drain outside thepremises•
The pipe shall be end
capped for futureconnection

EFFLUENTQUALITY

MAINTENCE OF
THE SYSTEM

Design for
effluent
discharge
downstream ofwater intake
pointsDesign shallallow regular
desludging

Averageeffluent quality•BOD : 50 mg/l
•Suspended
Solid : 100mg/

Individual
Development
Outside The
Local Authority
Areas

Desludging
shall be atleast once very
3 years.

Owners must becompelled toadhere to rules
and requirement

Product must be approved by SPAN• Complying with determined effluent
standard• Trenches to be provided for final effluent
discharge• Raised soak away shall be provided ifwater table is high• Desludging activities must be provided byregistered desludging contractor

All soak away shall belocated 5m downstreamof wells for domestic
consumptionDESIGN CAPACITY For 31 – 149 PE(6.975 – 33.525 m3/day)Diagram : Schematic Diagram of SSTS

TREATMENT PRINCIPLES

Limited todevelopmentwith lower
population
size

Additional
aerationprocess atthe secondtank forremoval ofBOD

Provideonly apartial
treatment

Low energy
consumption

The functionof key
components
does notrequire
intensive
energy andtechnicalability foroperation

SERVICE
LICENSEE• Performance anddurability

FACILITY
LICENSEE• Quality and needfor industry
ACCREDITATION
BODIES• Compliance tospecifications

SECTION45

SECTION
180(a)(i)• Plans and specifications for the construction ofsewerage systems and septic tanks require theapproval of the Commission• The Commission may make such rules toprovide for the minimum standards andspecifications which shall be used in thedesign, construction, installation, protection,
operation and maintenance of any watersupply system or sewerage system

MALAYSIAN SEWERAGE INDUSTRY GUIDELINESVOL. 5 – SEPTIC TANKS• 3rd Edition January 2009
• Published by SPAN

MALAYSIAN STANDARD ON SITE TREATMENTUNITS PART 1 : PREFABRICATED SEPTIC TANKSSPECIFICATIONS• Publish on June 2012

MALAYSIAN STANDARD ON SITE TREATMENTUNITS PART 2 : PACKAGED PREFABRICATED SMALL
SEWAGE TREATMENT SYSTEM SPECIFICATIONS• Draft approved by ISC D on November 2014

TECHNICAL SPECIFICATION SEWAGE TREATMENTSYSTEMPart 1: Prefabricated Tanks ‐ Packaged Plants• First Edition October 2010, Revision March 2013
• Publish by SPANTECHNICAL SPECIFICATION SEWAGE TREATMENTSYSTEM
Part 2: Construction and Installation ‐ Packaged Plants• First Edition October 2010, Revision March 2013
• Publish by SPANPURPOSE• To set up the requirements ofSPAN for design and constructionof Individual Septic Tank

APPLICATION• Development with populationequivalent size up to 150 PE• For single development shall not
more than 30 PE

EFFLUENT DISCHARGE STANDARDS• Standards based on Environmental Quality(Sewage) Regulations 2009 under Environment
Quality Act 1974
• Regulate by Department of Environment Malaysia(DOE)• Standard A for upstream water intake point andStandard B for downstream

LIMITATION• Septic tank performance may not be on aconsistent basis to meet DOE standards• For this reason, the effluent discharge
downstream shall met:
• BOD5 : 50 mg/L
• Suspended Solids : 100mg/L

GENERAL GUIDELINESDESIGN GUIDE‐ Initial consultation‐ Planning‐ Condition where
public sewer available
and not available‐ Design‐ Homestead
Developments‐ Non‐proprietarysystems‐ Proprietary systems

SEPTIC TANK LOCATEDIN SENSITIVERECEIVINGWATERCOURSE‐ Further treatment
methods for achieving
higher effluent quality‐ DisinfectionEffluent Discharge to Rivers / StreamParameter(mg/l unlessotherwisestate)

BOD5Standard A

Effluent Discharge to * Stagnant Water Bodies

Standard B

Standard A

Standard B

Absolute

DesignAbsolute

DesignAbsolute

DesignAbsolute

Design

20

1050

20

20

1050

20

SS

50

20

100

4050

20

100

40

COD

120

60

200

100

120

60

200

100

AMN

10520

10

52

52

NitrateNitrogen

20

1050

20

105105N/A

N/A

N/A

N/A

521055210552105TotalPhosphorus

O&G

SCOPE
• Requirement for prefabricated septictanks and their associated fittings• Treatment of sewage for up to 30 PE• Installed below ground level• Serve one premise only
• Two materials covered, FRP & PE
• Intended for use by consultants,designers, manufacturer, certifying
bodies, installers, regulators andother interested parties

Capacity

Inlet & Outlet
fittings

Flow path

Openings

Anchorage

Filter media

Partitions

Marking

Thickness

SEPTIC TANKS – GENERAL USAGEREQUIREMENTS• Only for total development < 150PE• Individual septic tank (IST) can only serveone premises• Size capacity – smallest (5PE) & largest(30PE)• Multiple IST within single lot not allowed

TYPES OF SEPTIC TANKS• Prefabricated• Cast In‐Situ

AS/NZS 1546 : 2008 ‐ On‐site domestic wastewater treatment units
Part 1: Septic Tanks
EN 12566: 2007 ‐ Small wastewater treatment systems for up 50 PT
Part 1: Prefabricated Tank
CAN/ CSA B66 : 2005 ‐ Design, material and manufacturing
requirements for prefabricated septic tanks and sewage holdingtanks

Malaysian Sewerage Industry Guidelines, Volume 5 ‐ Septic Tanks
Water Services Industry Act 2006
Water Services Industry (Desludging and Septage Discharge) Regulations
2008 [Draft]

SCOPE• Requirement for packaged prefabricatedsmall sewage treatment system (SSTS) andtheir associated fittings• Designed for sewage flow of 31 up to 149 PE• Installed below ground level• No vehicle load and not installed in highwater table area
• Two materials covered, FRP & PE
• Off‐site assembled• Intended for use by consultants, designers,
manufacturers, certifying bodies, installers,
regulators and other interested parties

Capacity

Inlet & Outlet
fittings

Openings

Anchorage

Filter mediaPartitions

MarkingThickness

Treatment
efficiency

SSTS – GENERAL USAGEREQUIREMENTS• Only for development 31PE ‐149PE• Prefabricated onlyMS 1225‐2:2006, Polyethylene (PE) tanks for cold water storage ‐ Part 1: Capacity more up to600 gal (first revision)
AS/NZS 1546.3: 2008, On‐site domestic wastewater treatment units ‐ Part 3: Aerated
wastewater treatment systems
BS EN 12566‐3+A1: 2009, Small wastewater treatment systems for up 50 PT ‐ Part 3:
Packaged and/or site assembled domestic wastewater treatment plants
CAN/ CSA B66: 2005, Design, material and manufacturing requirements for prefabricatedseptic tanks and sewage holding tanks

Malaysian Sewerage Industry Guidelines, Volume 5 ‐ Septic Tanks
Water Services Industry Act 2006
Water Services Industry (Desludging and Septage Discharge) Regulations 2008 [Draft]

To elevate and maintain thequality of on‐site treatment
system produced by the
manufacturers at desirable
level to perform as required

To ensure necessary certification
is obtained thus manufacturers
are more responsible andaccountable.

By specifying the requirements and test specification, it will;
Enable Septic Tanks and SSTS to be
manufactured/ constructed incompliance to manufacturing
requirements and performance
criteria established in the standard

End users will have theopportunity in having goodquality and certified products

SCOPE• Requirements for
packaged sewage
treatment plantconsisting prefabricatedtanks made of FRP or PE• Serve between 150 and5000 populationequivalents

SPECIFICATION• Performance requirements andassociated test methods for theprefabricated tanks and their accessories
that are installed buried in the groundwith no vehicles loads are applied aboveit• Marking requirements and evaluation ofconformity for the prefabricated tanks

SPECIFICATION• Operational requirements and performance
criteria that deal with features such asfunctional design and material as means ofcompliance with overall requirements of thepackaged plant• Focus is on operational systems of the plantcomprising piping, aeration, pumping,
control and other ancillaries• Specification also includes treatment
efficiency testing to ascertain if the plantachieve the effective and reliable
operational performance under normal
operating conditions throughout its
serviceable life spanWell Planned
SewerageServices

Good Quality
AssetsADVANTANGE & DISADVANTANGE OF ON-SITE TREATMENTSYSTEMADVANTAGES• Low installation cost
• Easy installation• Serving a single premise

DISADVANTAGE• Inconsistent treatment
performance• Require regular desludging
frequency of once every 3years• Capacity allowed only up to30PE• Lacking of Enforcement

SEWAGE CHARACTERISTICS AND EFFLUENT QUALITYCOMPONENT(IDEAL)
INFLUENTPE
RANGE

BOD

COD

SS

TN

NH3-N

Oil &Grease

All

All

250500300

503050

BOD

COD

SS

NO3-N

NH3-N

Oil &GreaseP*

EFFLUENTINDIVIDUAL SEPTICTANKPARAMETER/CONCENTRATION (mg/l)

CAPACITY
RANGE(m3/day)P*

5 - 301.12 – 6.75

50

200

100

N/A

N/A

N/A

N/A

31 - 149

6.97 – 33.52

3516075

N/A

N/A

7.510²SMALL SEWAGE

TREATMENT SYSTEM

CHALLENGES IN DETERMINING THE DESIGN INFLUENT PARAMETERS
The influent parameter in Malaysia mostly diluted due to infiltrationand illegal discharges from rain gutter
Note :

1Only applicable for effluent discharge to stagnant water bodies such as lakes and ponds
2 The proposed effluent parameters for SSTS

WAY FOWARD

End users will
have theopportunity inhaving goodquality andcertifiedproducts

To
standardize
on-sitetreatment
system

To elevate andcontrol thequality ofprefabricatedcomponents ofthe systemproduced bymanufacturers

To ensurenecessarycertification is
obtained thus
manufacturers
are more
responsible andaccountable

To ensure thesystem would
be able toprovidetreatment
efficiency asintendedTo ensureconstruction andinstallation is at
desirable level toperform as
requiredTo specify levelof operation andmaintenancerequired as
defined for thesystem

THANK YOUSEWERAGE REGULATORY DEPARTMENTNATIONAL WATER SERVICES COMMISSION
MALAYSIA