DANIDA-SARAWAK GOVERNMENT Urban Environmental Management System

Environment Engineering Monitoring and Auditing Laboratory Services Occupational Health and Safety

CHEMSAIN KONSULTANT SDN BHD

DANIDA-SARAWAK GOVERNMENT

Urban Environmental Management

System Project

ESTABLISHING AN OVERVIEW OF THE

CURRENT MANAGEMENT OF OIL AND

GREASE IN FOOD OUTLETS IN KUCHING

Date February, 2004

Ref CK/0113/012/03

FINAL DRAFT REPORT

DANIDA-SARAWAK GOVERNMENT

Urban Environmental Management System

Project

ESTABLISHING AN OVERVIEW OF THE

CURRENT MANAGEMENT OF OIL AND

GREASE IN FOOD OUTLETS IN KUCHING

Date February 2004

Report No.

Issue No.

Date of Issue

Prepared Chemsain Konsultant Sdn Bhd

Checked

Approved

Establishing An Overview Of The Current Management Of Oil And Grease In Food Outlets In Kuching

C:\Documents and Settings\user\Local Settings\Temp\_AZTMP111_\Exec\River Environmental Quality\UEMS_TEC_02_15-An overview on the cur mgt of oil&grease in food outlets-Finaldraft.doc

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Table of Contents

1 Background 4

2 Objectives 5

3 Scope of Work 6

4 Methodology 7

4.1 Study Boundary 7

4.2 Identification of FOs 8

4.3 Definitions of Food Outlets 9

4.4 Jurisdiction 9

4.5 Type of Oil & Grease Trap 9

4.6 Licensing Conditions 10

4.7 Location and Accessibility of Oil and Grease Traps 10

4.8 Performance of Oil and Grease Traps 10

4.9 Current Management of Solids and Oil and Grease 11

5 Findings 12

5.1 Food outlets’ licensing conditions 12

5.2 Food Outlets Surveyed 13

5.3 Coverage of Oil and Grease Traps 15

5.4 Types of Oil and Grease Traps used and Performance 16

5.5 Location and Accessibility of the Traps 24

5.6 Present collection and removal of solids and oil and grease 25

6 Conclusion 26

7 Recommendations 27

7.1 Establishment of Standard for Oil and Grease Sizing 27

7.2 Collection of Oil and Grease 28

7.3 Pilot Study 29

List of Figures



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Figure 1: Food Outlets Breakdown by Councils

Figure 2: Locations of Food Outlets Surveyed

Figure 3: Typical Cross Section of Oil and Grease Trap (DBKU)

Figure 4: Typical Cross Section of Oil and Grease Trap (MBKS)

Figure 5: Breakdown of the Surveyed Food Outlets by Councils and Unsur-

veyed FOs

Figure 6: Coverage of Oil and Grease Traps by Councils

Figure 7: Breakdown of Types of Oil and Used in MBKS Jurisdiction

Figure 8: Breakdown of Types of Oil and Grease Used in DBKU Jurisdiction

Figure 9: Performance of Oil and Grease Traps Used in MBKS Jurisdiction

Figure 10: Performance of Oil and Grease Traps Used in DBKU Jurisdiction

Figure 11: Performance of Oil and Grease Traps Used in MPP Jurisdiction

Figure 12: Typical O & G Trap Schematic Diagram

Figure 13: Sg. Bintangor Catchment Boundary

List of Appendix

Appendix A Sample of Survey Form for the Oil and Grease Survey

Appendix B Results of Oil and Grease Survey

Appendix C Licensing Conditions of the Local Councils

Appendix D Catalogues for Oil and Grease Trap

Appendix E Calculations for Comparison of Oil and Grease Traps

Appendix F Recommended Sizing and Calculations of Oil and Grease Trap



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List of Abbreviations

DBKU Kuching North City Hall (Dewan Bandaraya Kuching Utara)

MBKS Kuching City South Council (Majlis Bandaraya Kuching Selatan)

MPP Padawan Municipal Council (Majlis Perbandaran Padawan)

O & G Oil and grease

FO Food outlet



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1 Background

From the Environment of Sungai Sarawak – Relationships Between City and

River Study, SUD Project (2001), food outlets (FOs) in Kuching’s central busi-

ness district might have been responsible for more than 70% of the oil and

grease discharge in the municipals’ drains. Although oil and grease trap is a

mandatory installation specified in food outlets’ license, the performance and

management of the traps have not been assessed.

Due to certain neglectful practices such as dumping accumulated oil and grease

downstream all these wastes (oil, grease and solids) have caused major over-

loads in the councils’ drainage and wastewater treatment facilities. Due to the

non-existence of treatment facilities for the accumulated oil and grease, they are

collected and dumped into solid waste bins, resulting in increase of collection

charges.

Instead of resorting to the above ways of disposing the oil and grease which

either pollute the surface water or increase to the load of waste to the municipal

solid wastes facilities, a way to treat or utilise the collected oil and grease has to

be devised. In fact, the State Government’s plan to implement a biogas plant at

the existing Matang Septic Sludge Treatment Plant will enable the oil and

grease to be included as one of the feed material that could be fed into the plant

for treatment and conversion into fertilisers.



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2 Objectives

The Ministry of Environment and Public Health and NREB have planned the

implementation of a pilot scheme aiming to assess the potential improvement of

the oil and grease waste management through the institution of a combined

trapping, collection and treatment system. In lieu of optimising this pilot

scheme, surveys on current food outlets’ oil and grease management are war-

ranted.

As such, the survey carried out is to:

Find out the current food outlets’ licensing conditions imposed by the

councils;

Obtain information on the actual coverage of oil and grease traps;

Obtain an overview of the general location and accessibility of the traps;

Examine the present collection and removal of solids and oil and grease;

Identify the types of oil and grease traps used and gauge their performance;

and

Estimate the amount of oil and grease generated from the FOs.

The results and findings from this study will be used to identify the supplemen-

tary technical studies to further improve the performance of the various types of

existing oil and grease trap utilised in Kuching’s food establishments and also

to assist in the planning of the pilot scheme.



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3 Scope of Work

Prior to carrying out the survey on the existing management of the oil and

grease at all food outlets, the scope of work are tabled during the kick off meet-

ing. In order to achieve the objectives of this survey the following scope are

carried out.

In demarcating the boundary of the study, the line of thoughts is to survey FOs

in all areas under the jurisdiction of the three councils namely namely Majlis

Bandaraya Kuching Selatan (MBKS), Dewan Badaraya Kuching Utara

(DBKU) and Majlis Perbandaran Padawan.

From previous study, Sungai Sarawak Baseline Study (2001), it was estimated

that there are five hundred plus food outlets located within the three councils.

As such, the aim is to survey all the food outlets to provide and overview of the

oil and grease management in the three councils. The result of the survey will

provide the answers to the objectives as listed in Section 2.



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4 Methodology

The study methodology follows closely the objectives of the study. As such,

for a study to be reflective of the current situation and practical to be carried

out, a survey boundary has to be identified. In the mean time, a survey form is

created (as attached in Appendix A) to assist in the information gathering.

Three groups of surveyors are assigned to carry out the survey. One form per

FO is to be used. The relevant data to be collected based on the survey form

are as follows:

• Name;

• Types of oil and grease trap installed;

• Respective councils’ licensing requirements for oil and grease manage-

ment;

• Actual coverage of the oil and grease trap (i.e. what kind of waste is being

fed through the trap);

• Description of the location of the trap;

• Relative accessibility of the trap and degree of convenience in cleaning it;

• Performance of Oil & Grease traps.

The following section describe the reasoning for the study boundary, classifica-

tion and each question in the survey form.

4.1 Study Boundary

As stipulated in Section 3.0, the study boundary is demarcated by areas within

the three councils, MBKS, DBKU and MPP. List of food outlets from the three

respective councils were obtained. Following that, the lists are used to identify

and confirm the licensing status of the FOs. As MPP covers a large area up to

Mile 23, the survey for MPP areas is limited up to Mile 7. This is because ar-

eas more than Mile 7 are less congested in terms of FO numbers and should the

collection system be carried out, it will not be feasible economically due to the

longer distance to Matang Septic Sludge Treatment Plant. In addition to that,



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the urban areas where the density of FO is higher are identified to be of a

higher priority at the time of study.

Table 1 shows the number of the existing FO in the three councils based on the

lists obtained from the three councils. From Table 1, there are a total of li-

censed 802 food outlets within the three councils. Only MBKS has the list for

the unlicensed food outlets, thus increasing the number of FOs to 867. With

reference to the focussing on urban areas and omitting areas further than Mile

7, the total number of the FO to be surveyed is 806 (see also Figure 1). This

value is much higher than the originally estimation of 500 FOs. However, the

survey will still cover the initially agreed numbers, which is in the range of 500

FOs.

Table 1: Number of Licensed and Unlicensed Food Outlets By Council

Council Licensed Unlicensed Total

MBKS 361 65 426

MPP 174 Not Available 174

DBKU 267 Not Available 267

TOTAL 802 - 867

Figure 1: Food Outlets Breakdown By Councils

Breakdown of Food Outlets Within Study Boundary

MPP, 113,

14%

MBKS, 426,

53%

DBKU, 267,

33%

4.2 Identification of FOs

Item A of the survey form provides the identification as well as the location of

the FOs. The FOs surveyed are identified by the signboard of the shop and ad-

dress is noted. Location is also marked on the map.



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4.3 Definitions of Food Outlets

For the survey, the existing food outlets are categorised into coffee shop; food

centre; fast food restaurant; and individual restaurant. In order to differentiate

between one food outlets to another, the following definitions are used to clas-

sify the food outlets. These definitions will ease the identification of different

FO during survey. Throughout the survey, it was noted that bakery is also con-

sidered as food outlet and subsequently included in the survey. This is included

in Item B of the survey form.

Coffee shop is defined as FO with one shop lot whereby heavy cooking is car-

ried out at the back of the shop. Usually the shop may have two to four stalls in

the coffee shop.

Food centre is considered as FO with more than 4 stalls and occupies more

than one shoplots. Normally, the FO licensees sell the drinks whereas the stalls

selling food are rented out.

Fast food restaurant is referring to FO which serves fast serving food such as

fried chicken and pizzas. The common fast food restaurants found in the sur-

vey are Sugar Bun, Kentucky Fried Chicken and Pizza Hut.

Individual restaurant is FO that is operated by a single operator whereby the

drinks and food are prepared from the same kitchen. There are no food stalls

for the individual restaurant.

4.4 Jurisdiction

Item C of the survey form indicates which council the FO is located in, MBKS,

DBKU or MPP.

4.5 Type of Oil & Grease Trap

Item D in the survey form provides information on the type of oil and grease

trap used. There are the choices of passive grease trap, precast concrete grease

trap. Passive grease trap refers to any type of oil and grease trap without any

mechanical installation, e.g. pumps. Precast concrete grease trap refers to

grease traps, which are made of concrete. Others could be local made stainless

steel trap or HDPE trap. There is also allocation to state if the grease trap is of

specific brand and also the space to specify the dimensions of the oil and grease

trap.

For the FOs with and without oil and grease traps, the strainer system (item E

of survey form) will give indication on the type of strainer used, may it be

stainless steel or plastic.

Information on what sort of food goes through the trap will also be reported as

indicated in item G of the survey form.



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4.6 Licensing Conditions

With reference to item F of the survey form, the licences displayed in the FOs

have to be examined with regards to oil and grease management, i.e. if oil and

grease trap is required. If so, is it a grease trap, oil trap or combination of oil

and grease trap.

4.7 Location and Accessibility of Oil and Grease Traps

The location of the trap is also noted as per item H of the survey form. The lo-

cation is meant by whether the trap is in the shop or outside, below sink, etc.

Item I) will provide a more detail information on whether the trap is easily ac-

cessible for the cleaning and maintenance. In addition to that, information of

the distance from the trap to the nearest exit and the ease of accessibility is also

recorded. This information will provide an overview on how easily accessible

the oil and grease trap will be for collection.

4.8 Performance of Oil and Grease Traps

In order to assess the performance of the oil and grease trap, two assessment

techniques will be adopted. One is by visual inspection (item J) of survey

form) and another is by the 25% Rule of Oil & Grease Trap Efficiency Test

(item L) of survey form).

4.8.1 Visual Inspection

Visual inspection is carried out by looking at the effluent of the oil and grease

trap and should any of the following criteria is matched: clear & smooth

effluent/no apparent release of O&G from trap/no by-pass of incoming flow

occurs, then, the performance of the oil and grease trap is considered as good.

However, should the effluent match any of the following criteria: murky &

obstructed effluent/O&G overflowing the trap /incoming flow diverted through

modified plumbing, then the trap is considered be bad and not performing.

The visual inspection will be carried out on all the surveyed FOs.

4.8.2 25% Rule of Oil & Grease Trap Efficiency Test

This 25% Rule of Oil & Grease Trap Efficiency Test will only be carried out on

selected outlets. Three establishments from each food outlet category in each

council will be carried out. As such, a total of 36 food outlets will be carried

out. The 25% trap’s efficiency test involves measuring thickness of grease

layer in the trap twice (i.e. before and after peak hours) according to the condi-

tions stated in the attached survey form (Item L of Appendix A). The peak

hours is noted to occur twice, i.e. 9 am to 10 a.m. and 12 p.m. to 1.30 p.m.



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The 25% test is based on the rule of thumb which states that if the grease layer

or the sediments in the oil and grease trap is more than 25% of the total effec-

tive depth of the oil and grease, then, the trap is not efficient anymore.

The rationale behind this is that the liquid retention time in the trap is reduced

by more than 25% hence warrant the trap unable to remove oil and grease ef-

fectively.

4.9 Current Management of Solids and Oil and Grease

Item K of the survey forms will give information on the existing conditions of

collection and removal of solid, oil and grease, the frequency and amount of oil

and grease removed, based on interview with the FO operator.



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5 Findings

This section will describe and summarise the findings from the oil and grease

survey carried out in the months of August to early October 2003. The details

of the survey are attached in Appendix B. The locations of the food outlets

surveyed are also enclosed in Figure 2 (see Appendix B for detailed FOs loca-

tion).

5.1 Food outlets’ licensing conditions

Based on the information gathered from the officers at the three councils,

MBKS, DBKU and MPP, it was found that the oil and grease trap is a require-

ment for two councils, namely MBKS and DBKU. It is one of the minimum

application requirements that the councils look into when new FO operators

apply for licence. In fact, DBKU has published a booklet titled Standard Min-

ima Premis Makanan. This booklet mentioned on the requirement of oil and

grease trap with the illustration as shown in Figure 3 below.

Figure 3: Typical Cross Section of Oil and Grease Trap (DBKU)

MBKS on the other hand, also have the minimum standard requirement. It is

stipulated in their “Application for Approval in Principle for Establishment of

Entertainment & Food Premises and Issue of Licences” form (Source: Data

Management of Public Complaints and Licences in Kuching Government

Agencies, April 2002) that oil and grease trap is required for kitchen with heavy

cooking but there is no guideline on the sizing. The following figure, Figure 4

shows the typical layout provided by the council to new FO operators applying

for license.



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Figure 4: Typical Cross Section of Oil and Grease Trap (MBKS)

When checked against the licensing requirements, it was found that the oil and

grease trap requirement is not in the license conditions enclosed at the back of

the FO license displayed on the wall for both MBKS and DBKU. The licensing

conditions displayed stresses more on hygiene, cleanliness and disposal of solid

wastes (see Appendix C). Based on verbal conversation with the officer s in

the Councils, the oil and grease trap usage will be checked every year prior to

renewal of licensing conditions.

For MPP, the installation of oil and grease trap is not a requirement in the ap-

plication conditions, nor is it in the licensing conditions. Similar to MBKS and

DBKU, the licensing conditions of MPP concentrates on hygiene, cleanliness

and disposal on solid wastes (Appendix C).

5.2 Food Outlets Surveyed

Of the 806 FOs in the three Councils, a total of 649 FOs had been surveyed.

This works out to be 80% of the total known number of FO (from councils)

(see Figure 5). The breakdown of the FOs by licensed and unlicensed catego-

ries is tabulated in Table 2.



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Figure 5: Breakdown of the Surveyed Food Outlets by Councils and Un-

surveyed FOs

Breakdown of Surveyed and

Unsurveyed Food Outlets by Councils

DBKU, 226

(28%)

M PP, 87

(11%)

Unsurveyed,

157

(19%)

M BKS, 336

(42%)

Table 2: Breakdown of FO Surveyed

Food Outlets Surveyed (10 October 2003)

Council MBKS MPP DBKU

L U L U L U

Total FO

Surveyed with /

without Licence

218 118 87 - 226 -

Total FO

Surveyed –

breakdown by

councils

336 87 226

% FO Surveyed

– breakdown by

councils

(336/426 x 100) =

79

(87/113 x 100) =

77

(226/267 x 100) =

85

TOTAL FO

SURVEYED

649

% TOTAL FO

SURVEYED

80

Note:

L – Licensed

U - Unlicensed



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5.3 Coverage of Oil and Grease Traps

Based on the results of the survey, it is concluded that DBKU has higher per-

centage of oil and grease traps installed at the FOs compared to MBKS and

MPP (see Table 3 and Figure 6 for illustration of FOs with and without O & G

trap).

Even though the application for FO license requires the need for O & G traps,

they are not always installed. The reasons could be due to the FOs abandoning

the use of O & G trap as maintenance is too much of a hassle, lack of

understanding of the fuction of O & G trap and possibly due to no follow up or

lack of enforcement from the Councils. There are also cases of O & G trap

being used for a while and later abandoned as experienced by the surveyors

when they go back to the FOs for double-checking on the performance. As

such, Council’s enforcement or checking during the yearly licence renewal may

not be sufficient. Lower percentage of o & g traps installed in the MBKS areas

could also be due to the licensing requirement which states that grease trap to

be provided for heavy cooking kitchens. ”Heavy cooking kitchen” refers to

kitchens which involve usage of substantial amount of oil for cooking of food,

i.e. frying and deep frying activities. As such, FOs operator could argue on the

point that their FOs do not involve heavy cooking.

As MPP do not require the FO to be installed with oil and grease traps, the FO

licensee only require to install strainers. As such, most outlets in MPP areas

only have plastic strainers installed. Among the FO surveyed in MPP area,

there are six FO installed with oil and grease traps.

Figure 6: Coverage of Oil and Grease Traps by Councils

Number of FOs Surveyed

336

226

8762

165

6

274

6181

0

50

100

150

200

250

300

350

MBKS DBKU MPPLocal Councils

Nu

mb

er

of

Fo

od

Ou

tlets

Total Surveyed

O & G

w/o O & G

Note: O &G – Oil and Grease Trap, w/o – without,



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Table 3: Breakdown of Results of Oil and Grease Trap (O&G Trap) Usage in the FO

Surveyed

Food Outlets Surveyed (10 October 2003)

Council MBKS MPP DBKU

Usage of O & G

Trap

W WO W WO W WO

FO With or

without

Licence

L U L U L U L U L U L U

Breakdown 35 27 183 91 6 0 81 0 165 - 61 -

Total Of FO with

/ without O & G

Trap

62 274 6 81 165 61

% FO with O &

G Trap

18 7 73

Note:

W - With Oil and Grease Trap

WO – Without Oil and Grease Trap

L – Licensed

U - Unlicensed

5.4 Types of Oil and Grease Traps used and Performance

5.4.1 Types

There are three main types of oil and grease traps used. They are local made

stainless steel (SS) o & g traps, precast concrete o & g trap (round and rectan-

gular) and high density polyethylene (HDPE) made o & g traps. Plate 1 –

Plate 4 show the different type of oil and grease traps in use at FOs.

Plate 1: Typical stainless steel o &

g trap with SS strainer.

Plate 2: Plan view of rectangular

precast concrete o & g trap.

Inlet

Outlet



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Plate 3: Circular precast concrete o

& g trap found at the Kuching Civic

Centre.

Plate 4: Typical HDPE o & g trap in

use.

Local made stainless steel o & g traps could be bought from aluminium work-

shops in Kuching such as those in Carpenter Street. HDPE made traps are

mostly supplied by Weida, a company mainly involve in manufacturing poly-

ethylene made products (see Appendix D for catalogues). The available sizes

are 50L, 100 L and 200 L capacity. Other oil and grease suppliers but products

not yet in use include Bioclear Sdn. Bhd.’s Wade Aclimatic Grease Converter

(see Appendix D) and oil and grease trap distributed by Jasa Kukuh Sdn. Bhd.

(verbally informed by DBKU officer) with the product known by the name of

SIMPAK®.

5.4.2 Sizing

Generally, the typical sizes (L x W x D) of stainless steel oil & grease trap are 2

ft x 1 ft x 1 ft and 2 ft x 1½ ft x 1½ ft. Based on the survey, it is noted that the

oil and grease trap of size 2 ft x 1 ft x 1 ft are utilised for coffee shops whereas

oil and grease trap of 2 ft x 1½ ft x 1½ ft are mostly utilised at food centres.

Bakeries on the other hand displayed a trend of utilising SS oil and grease trap

of size 2 ft x1½ ft x 1½ ft.

For MBKS jurisdiction, SS oil and grease traps are the most commonly used

traps followed by precast concrete and HDPE. The percentage breakdown of

traps used is shown in Figure 7.

In DBKU jurisdiction, SS oil and grease is also the most commonly used traps

whrees precast concrete and HDPE have the same percentage of usage. The

breakdown is hsown in Figure 8.

Inlet

Outlet



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Figure 8: Breakdown of Types of Oil and Grease Used in

DBKU Jurisdiction

HDPE

1%

Precast Concrete

1%

Stainless Steel

98%

Precast Concrete

Stainless Steel

HDPE

5.4.3 Efficiency

As explained in Section 4.8, there are two methods of accessing the efficiency

of oil and grease traps, i.e. by visual inspection and 25% rule. The results of

the efficiency via visual inspection is summarised in Figure 9, Figure 10 and

Figure 11 for MBKS, DBKU and MPP jurisdictions respectively. For the ef-

fluent outlets which could not be seen, they are deemed not detected. The re-

sults show that the efficiency of most of the oil and grease traps are good based

on the criteria set in Section 4.8.1.

Figure 7: Breakdown of Types of Oil and Grease

Used in MBKS Jurisdiction

Precast Concrete

5% HDPE 18%

Stainless Steel 77%

Precast Concrete

Stainless Steel

HDPE



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Figure 9: Performance of Oil and Grease Traps Used in

MBKS Jurisdiction (Visual Inspection)

Bad

6%

Not Detected

5%

Good

89%

Bad

Good

Not Detected

Figure 10: Performance of Oil and Grease Traps

Used in DBKU Jurisdiction (Visual Inspection)

Not Detected

9%

Bad

22%

Good

69%

Bad

Good

Not Detected



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Figure 11: Performance of Oil and Grease Traps

Used in MPP Jurisdiction (Visual Inspection)

Bad

33%Good

67%

Bad

Good

For 25% rule efficiency test, the results are tabulated in Table 4 (see Section

4.8.2 for methodology of 25% rule efficiency test). Visually, the oil and grease

traps efficiency are mostly good whereby the effluent looks clear and flow

smoothly as well as the fact that there is no apparent release of O&G from trap.

However, the detailed survey on 12 FO per council which is carried out base on

the 25% Rule on the selected food outlets showed that the oil and grease trap

efficiency are in fact classified not efficient. This is due to several reasons:

• Accumulation of oil and grease and solids are already more than 25% of

the total effective height of the oil and grease traps in the morning (before

peak period) (see Table 4). With the 25% rule, the thickness of the oil

and grease should not be more than 25% for the oil and grease trap to be

effective, as such, should the oil and grease be more than 25%, this mean

that the oil and grease trap is deemed not efficient. The rationale behind

this is that the liquid retention time in the trap is reduced by more than

25%, hence warrant the trap unable to remove oil and grease effectively.

• Oil and grease traps are not cleaned as often as mentioned during initial

survey. If they are cleaned daily as claimed, then the grease level will be

below 25% early in the morning (assuming they clean at the end of the

day) or during the second measurement (after lunch peak period).

• For those that are cleaned daily, the results show the oil and grease traps

are not efficient. This is most probably due to the capacity of the oil and

grease trap being under sized.

• Effluent may have the characteristics of “good efficiency” visually.

However, when there is stagnant flow, a film of oil could be seen in the

drains but would not be seen when inspecting visually. This is further

confirmed by the comparison of visual inspection versus 25% rule test in

Table 4. Eventhough the visual inspection indicates the oil and grease trap

is efficient, the 25% rule showed a negative results, i.e. bad eficiency.



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Figure 12: Typical O & G Trap Schematic Diagram

•



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Table 4: Results of 25% Rule Efficiency Test

NAME A B C D (B >25% A) (C >25% D) (B >25% A) (C >25%D)

Efficiency

(25% Rule)

Effcien-

cy (Vis-

ual) O&G Types

Fre-

quency

BEFORE

PEAK

BEFORE

PEAK AFTER PEAK AFTER PEAK

DBKU Jurisdiction

SMK Star

20"

20"

V.

Thick 2" More Than 25% More Than 25% More Than 25% More Than 25% BAD BAD HDPE (24"x18"x18") Daily

I Café

17"

17"

V.

Thick 1" More Than 25% More Than 25% More Than 25% More Than 25% BAD GOOD S.S(48"x16"x17") 2x week

G . M Nur

14"

14"

V.

Thick 1" More Than 25% More Than 25% More Than 25% More Than 25% BAD BAD S.S(24"x18"x18") 3 x week

D'aliff Rest

14"

14" 0.4" 1" More Than 25% More Than 25% More Than 25% More Than 25% BAD BAD S.S(22"x14"x14") Daily

Oriental Kitchen

14"

14" 0.4" 1" More Than 25% More Than 25% More Than 25% More Than 25% BAD GOOD S.S(22"x14"x14") Daily

Denis Place

14"


Saujana

32"

32" 4" 2" More Than 25% More Than 25% More Than 25% More Than 25% BAD GOOD RC(46"x36"x32" 2x week

H2O

14"

14" 0.4" 1" More Than 25% More Than 25% More Than 25% More Than 25% BAD BAD S.S(22"x14"x14") Daily

Wanniey F. Centre

14"

14" 2" 1" More Than 25% More Than 25% More Than 25% More Than 25% BAD GOOD S.S(22"x14"x14") Daily

Kyros Kebab

12" 0.2" 0.2" 1" Less than 25% Less than 25% Less than 25% Less than 25% Good GOOD S.S(24"x18"x12") Daily

SCR

14"

14" 0.4" 1" More Than 25% More Than 25% More Than 25% More Than 25% BAD GOOD S.S(22"x14"x14") 1 x week

Caprilla

12"


Note:

A – Bottom of Outlet Pipe to Bottom of Tank

B – Grease layer

C – Settled Solids

D - Bottom of Outlet Tee to Bottom of Tank

Refer to Figure 12 for indication of locations for A - D



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NAME A B C D (B >25% A) (C >25% D) (B >25% A) (C >25%D)

Efficiency

(25% Rule)

Effcien-

cy (Vis-

ual) O&G Types

Fre-

quency

BEFORE

PEAK

BEFORE

PEAK AFTER PEAK AFTER PEAK

MBKS Jurisdiction

Melor Café

14" 0.2" 0.2" 1" Less than 25% Less than 25% Less than 25% More Than 25% BAD GOOD S.S(22"x14"x14") 2xweek

Kok Ming

14" 14" 1" 1" More Than 25% More Than 25% More Than 25% More Than 25% BAD GOOD HDPE(18"x10"x14") 1xweek

Chilliepeppers

14" 14" 3.5" 1" More Than 25% More Than 25% More Than 25% More Than 25% BAD GOOD S.S(22"x14"x14") 2xweek

Sichuan Caiguan

14" 0.4" 0.4" 1" Less than 25% Less than 25% Less than 25% More Than 25% BAD GOOD S.S(22"x14"x14") 1xweek

Ten Ichi Restau-

rant

24" 0.78" 0.78" 2" Less than 25% Less than 25% Less than 25% More Than 25% BAD GOOD S.S(52"x20"x24") Daily

Taiwan Taste

17"

17"

V.

Thick 1" Less than 25% Less than 25% More Than 25% More Than 25% BAD GOOD HDPE(18"x10"x14") Daily

KFC

14" 0.4" 0.4" 2" Less than 25% Less than 25% More Than 25% More Than 25% BAD BAD S.S(22"x14"x14") Daily

McDonald 14"

v.

Thick

v.

Thick 2" More Than 25% More Than 25% More Than 25% More Than 25% BAD GOOD S.S(22"x14"x14") Daily

Sugar Bun

12" 0.2" 0.4" 1" Less than 25% Less than 25% Less than 25% Less than 25% GOOD GOOD S.S(24"x18"x12") Daily

My Provide

14" 14" 3.5" 1" Less than 25% Less than 25% Less than 25% Less than 25% GOOD GOOD S.S(22"x14"x14") 1xweek

Khadijah Café

14" 14" 3.5" 1" Less than 25% Less than 25% More Than 25% More Than 25% BAD GOOD S.S (24"x 18"x18") Daily

Rest SCR

14" 14" 3.5" 1" Less than 25% Less than 25% More Than 25% More Than 25% BAD GOOD S.S (24"x 18"x18") Daily

MPP

Najmi Café

14" 14" 3.5" 1" Less than 25% Less than 25% More Than 25% More Than 25% BAD GOOD S.S(22"x14"x14") 2xweek

KFC BT. 7

14" 14" 3.5" 1" Less than 25% Less than 25% More Than 25% More Than 25% BAD BAD S.S(22"x14"x14") Daily

SUGAR BUN BT.

7

12"

12" 0.4" 1" Less than 25% Less than 25% More Than 25% More Than 25% BAD GOOD S.S(24"x18"x12") Daily

KFC MJC

14" 14" 3.5" 1" Less than 25% Less than 25% More Than 25% More Than 25% BAD BAD S.S(22"x14"x14") Daily



24

.

In order to access the current capacity of the oil and grease trap used and com-

pared with oil and grease traps sizing with other countries, Denmark and the

United States of America (US), the following conclusions are made. For sizing

criteria, calculations and assumptions made for each method, refer to Appendix

E.

Table 5: Comparison of Oil and Grease Sizing for Different Methods (300 meals@ 4

L/s)

Local Made

Stainless Steel*

WEIDA Denmark

method

US Method

Size (L x

W x D)

(2 x 1.5 x 1.5) ft (0.64 x 0.44

x 0.45 ) m

(1.6 x 0.9 x

0.5 ) m

-

Residence

time (s)

15.5 # 25 # 180 5400

Effective

volume

62 L 100 L 720 L 1710 L

Note:

*Local Made O & G - Typical from Survey # Based on Denmark method, assume all calculations are for 300 meals, with

flow of 4 l/s.

Based on Table 5, it could be concluded that the exisitng oil and grease traps

used currently in Kuching are small in terms of capacity when compared with

the Denmark and US method. However, for a more practical approach in

improvising the sizing of the oil and grease trap, the Denmard method will be

used as it has a lower residence time and been proven to work in Denmark. US

method is not chosen as it would give a large volume and is not very realistic to

install or provide an oil and grease trap of that size.

5.5 Location and Accessibility of the Traps

The locations of the oil and grease trap are mostly located below sinks, outside

and behind shops or adjacent to sinks. Most of these oil and grease traps are

not hindered (see Plate 5 and Plate 6).

Distance of oil and grease trap to the nearest exits ranges from 1 m - 6 m.

There are normaly no hindrance from the oil and grease traps to the exits.

Details could be checked in Appendix B.



25

.

Plate 5: Typical location of o & g trap

is below sink.

Plate 6: Another location of o & g

trap below sink.

5.6 Present collection and removal of solids and oil and grease

From this survey, the findings show that there is no collection of oil and grease

from the O & G trap available commercially. The general procedures for oil

and grease trap maintenance carried out by the FO operators are removing of

the solids from the strainers and scooping of the oil and grease into plastic bags.

These are then disposed off at the communal or individual garbage bins. This

mode of disposal is recommended by the councils and the recommended fre-

quency is twice a week. The surveyed result shows that most of the FO opera-

tors clean their oil and grease traps daily. The frequency other operators clean

their oil and grease traps either twice a week or once a week.

5.7 Estimated Amount of Oil and Grease Collected

From the collected data, it is noted that the amount of oil and grease removed

from the trap in a FO ranges from 0.5 – 10 kg per day. From the survey result,

it is noted that lower end range of oil and grease generated (0.5 kg) correspond

to mostly to coffee shops whereas fast food restaurant and individual restaurant

generate the higher end of the range of oil and grease (10 kg). It should be

noted that this amount is very subjective and based on interview with the FO

operators. These data, however, could not be verified.

An estimation on the amount of oil and grease that can be potentially collected

from Fos in Kuching is given as follows. Based on 806 FOs (the number of FO

which are within the survey area), for a minimum 0.5 kg per day of oil and

grease, the minimum amount oil and grease which could be collected daily is

0.4 tonnes per day. For this calculation, it is assumed that all the FOs produce

the same amount of oil and grease daily. However, the mid range of 5 kg per

day, the amount of oil and grease that could be collected from the 806 outlets

are four tonnes and the maximum oil and grease that could be if the assumption

that all the FO produce 10 kg per day will be 8 tonnes per day.



26

.

6 Conclusion

Based on the findings in Section 5, the following conclusion is deduced.

• In terms of requirement for installation of oil and grease traps in FOs, only

MBKS and DBKU have the requirements. MPP only stressed on the needs

for the solids to be separated from the sink discharge. The percentage of

FOs having oil and grease traps installed is higher in DBKU compared to

MBKS.

• The three types of oil and grease commonly found is local made stainless

steel and more sparsely used are precast concrete and HDPE made oil and

grease traps.

• Current management of the oil and grease is by scooping the oil and grease

into plastic bags and dumped into garbage bins for disposal into the mu-

nicipal dumpsite in Matang. This is the management method recom-

mended by the Councils as there is currently no facility available to treat

the oil and grease.

• The efficiency of the oil and grease trap is concluded to be not efficient.

This is due to two main reasons, namely undersized oil and grease trap;

and insufficient maintenance of oil and grease trap.



27

.

7 Recommendations

Based on the above findings and conclusions, there are several recommenda-

tions to be carried out for short term and also long term effect of the oil and

grease management.

7.1 Establishment of Standard for Oil and Grease Sizing

Based on the findings of this survey, there is no doubt that a standard for sizing

is required for FOs operators based on the O & G loading generated at their

FOs. Not only will the standard sizing be easy to enforce by the Council side,

the FO operators will be able to allocate the appropriate space for the oil and

grease trap installations.

Based on the findings, the consultant has come up with the oil and grease

design based on the Danish local authority standard. Three different sizings are

designed and the recommended installation are as shown in Table 6 (see

Appendix F for sizing calculations).

Table 6: Sizings of Oil and Grease Traps for different FOs

No. Type of Food Outlets (Assumption) Effective Capacity

1. Food Centre (100 meals per stall ) 360 L (per stall)

2. Coffee Shop (3 stall) 720 L

3. Individual Restaurant (600 meals per day) 1440 L

The above sizing are tentative and subject to the findings of the pilot study.

In the long term, once the standards sizing are established, these knowledge

should be extended to the existing and future FOs. It is recommended that

importance of the oil and grease maintenance be conveyed to the FOs.



28

.

7.2 Collection of Oil and Grease

Without proper collection, the oil and grease from the FOs will still end up in

the drain or the municipal dumpsite. As such, the need for proper collection

system is indeed important. There are a few ways to collect the oil and grease.

There is the option of scooping of the oil and grease by the FOs and accumulate

in a dedicated containers and be collected by a third party or be collected via a

special machine by a third party directly from the FOs. There is a machine

known as Dung Beetle which could be used to collect the oil and grease from

the individual FOs. The following picture shows the Dung Beetle. Table 7

shows the specification of the machine.

Centralised washing is also one of the recommendations to be implemented on

new food outlets. This would ease the implementation of oil and grease trap

installation and collection.

Plate 7: Dung Beetle



29

.

Table 7: Specifications of Dung Beetle

Type 2-wheeled universal “walking” tractor.

Engine 4 stroke 12 hp Diesel engine with recoil starter.

Transmission 4-speeds forward plus 1 reverse. Engageable differential lock.

PTO: Independently operating. Vacuum pump powered through V-belt.

Max. speed 12 km per hour.

Brakes Handle operated drum brakes on front wheels with engage able park-

ing brake. Pedal operated drum brakes on rear wheels.

Turning radius

within

kerbs/walls

3.05 metres within kerbs, 3.3 metres within walls

Body Self-supporting tank, twisting angle through pivot point limited to +

20 degrees

Overall length 3.5 metres.

Overall width 1.1 metres.

Total weight Empty ~675 kg, fully loaded including driver ~1550 kg.

Vacuum pump

capacity

4300 litres per minute.

Maximum vac-

uum in tank

- 0.8 bar.

Positive pres-

sure

0.5 bar.

Sludge tank Net operating volume approx. 800 litres.

Suction valve 3” ball valve, top mounted.

Discharge valve 3” ball valve, bottom mounted.

7.3 Pilot Study

In order to improve the current oil and grease management, a pilot scheme is

recommended to be set up. This pilot study will incorporate installation of new

and larger oil and grease traps in a “selected” study area. Means to monitor the

new installations should also follows. As such the consultant has identified Sg.

Bintangor Catchment to be the area of pilot study (see Figure 13).

The reason Sg. Bintangor is chosen in lieu of installing new oil and grease trap

in MPP areas which do not have oil and grease traps are for the ease of moni-

toring. Should other areas be chosen, then the result may not be as easy to

monitor as the discharge may be to different catchments. Another reason is due



30

.

to the fact that Sg. Bintangor Catchment area is within DBKU jurisdiction,

which has a higher percentage of oil and grease traps being installed. As such,

the drainage systems are anticipated to be centralised to one outlet, therefore

minimise the renovation works to be carried out, thus lower cost implication as

well as minimise disturbance to the FOs operators. Last but not least, the rec-

ommendation of Sg. Bintangor Catchment is also in line with the State Gov-

ernment’s policy to improve the water quality of Sg. Bintangor. As such, Sg.

Bintangor catchment is the obvious choice as from previous Danish Coopera-

tion Environment and Development (Danced) funded project, the detailed land

uses and drainage of the Sg. Bintangor Catchment is available.

To monitor the water quality before and after improvement, a 3-Tier Monitor-

ing Program is devised.

• Tier 1: Localised – Monitoring of effluent discharge at oil and grease trap /

direct discharge outlets.

• Tier 2: Monitoring of effluent discharge downstream - drains downstream.

• Tier 3: Overall catchment - Monitoring of Sg. Bintangor.

Tier 1: Localised

This is a localised approach to monitor the effluent discharge at oil and grease

trap / direct discharge outlets (for FO without Oil and grease trap). In order to

monitor whether the new installation has shown any improvement or not, the

following procedures are recommended:

• Collect sample of 100 ml from O & G trap or discharge outlet using glass

beaker,

• Let the sample sit for 15 minutes,

• Measure oil & grease layer

• Record

The above procedures are to be carried out before and after new installation.

The frequencies of collection is recommended to be twice a day for

comparison, twice a month for two consecutive days (duplicates). The

duration of monitoring is suggested to be three months and if required, the

monitoring could be extended to 6 months or one year.



31

.

Tier 2: Downstream Drains

This Tier 2 will provide a micro view whether there is any improvement

resulting from the new installation. The sampling locations are at the

downstream of several oil and grease traps discharges. The following

procedures are recommended to be carried out:

• Collect samples from the downstream drain and to be analysed for the

parameter oil and grease.

Similar to the Tier 1 procedures, the samples are to be collected before and

after new installation. The frequencies is recommended to be twice a day for



monitoring may extend to 6 months or one year.

Tier 3: Overall catchment

Tier 3 will provide an overall view (macro) on the effectiveness of the new

installation. This is monitored by monitoring the water quality of Sg.

Bintangor.

• Collect samples from the Sg. Bintangor and be analysed for the parameter

oil and grease.

Similar to the Tier 1 and Tier 2, the samples are to be collected before and after

new installation. The frequencies is recommended to be twice a day for



monitoring may extend to 6 months or one year.

Once the pilot scheme is sucessful, it could be extended to other areas such as

Mile 7 and Batu Kawa New Township.

7.3.1 Additional Work

Based on the survey carried out, there are ninety five FOs within the Sg.

Bintangor Catchment area. While the choice of Sg. Bintangor is a sound one,

the forseeable problem related to this new installation will be limited space

available. As such, a separate study under the pilot scheme has to be carried

out to determine where to install the oil and grease trap and the adequacy of

space for the installation.

Concurrently with the implementation of the pilot scheme, the collection

system should also be in place to ensure that the collected oil and grease could

be collected and disposed properly.

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