A Study of Waste Cooking Oil Management of Food Services in Phnom Penh, Cambodia

By Mongtoeun Yim,¹ * Vin Spoann,² and Takeshi Fujiwara³
December 2018

Department of Environmental Science, Royal University of Phnom Penh, Cambodia * Corresponding Author
Graduate School of Environmental and Life Science, Okayama University, Japan
Waste Management Research Center, Okayama University, Japan

Abstract
A survey of waste cooking oil (WCO) management of food services in Phnom Penh, Cambodia was carried out. The research was conducted by selecting food services from three categories which include C.P. Cambodia Co., LTD, Street vendor and fast food restaurants. The samples were selected from six Khans which are 7 Makara (6.3%), Daun Penh (12.5%), Chamkarmorn (18.8%), Meanchey (18.8%), Toul Kork (18.8%) and Sen Sok (25%). Based on the result from questionnaire shows that 55% of respondents are women. Number of guests used each source indicated that at weekend more people go to food services. The amount of cooking oil consumption and WCO generation were measured, the result was 13-18 l/day and 7-10 l/day respectively. Anyway, storage and disposal of WCO were well managed by keeping in plastic container 7% and steel container 93%. And WCO was generated higher on weekend and holiday than working day. Cooking oil was changed every three days up to 68.5%, 2 days (12.5%), 4 days (6.3%) and 7 days (12.5%). The survey also revealed that 100% of the sources sold their WCO to second buyer. In terms of health awareness, it was found that 80% of the food services used the WCO 2-3 times before disposing it, while 20% of the rest used 4 times and 7 times. As a conclusion, this study shows that the food services are aware of proper WCO management. However, public awareness campaign is still necessary in order to encourage them to more effectively manage their WCO. The awareness campaign should put more emphasis on the direct and indirect effects of improper disposal and continuing reuse of WCO in food preparation after usage of two or more times. A comparative study with different populations would assist in generalising our conclusions. Organisations responsible for managing WCO will benefit from additional empirical studies among communities in other parts of Cambodia.

Keywords: Food Services; Waste Cooking Oil; Environment; Health; Management

1. Introduction

Phnom Penh, the capital of Cambodia, is one of the highest populated city in Cambodia. High production of WCO is associated with the urbanization, rapid growth and high economic development. Urbanization is making more people come to the capital due to main task such as study, business and work. Phnom Penh population has increased from 1.3 million in 2008 (NIS, 2008) to 1.5 million in 2012 (Facts Phnom Penh City, 2012). It is estimated to be 2.2 million in 2014 according to the world population review (World Population Review, 2014). Total land area of Phnom Penh has expanded from approximately 374 km² (JICA, 2005) to 678 km² in 2010 (MPP, 2012). Phnom Penh is divided into 9 districts (khans) with 96 communes (Sangkats) with an average population density of 4,572 km² and mean household size of 5.1 (NIS, 2008). At the end of 2013, 3 new districts (khans) were established. At the same time the number of food services such as CP, street vendor, fast food restaurants, local style restaurants, western style restaurants and CP, street vendor and fast food restaurants are among others that produce high quantity of WCO.

Cooking oil is commonly used for preparing food in our modern society. The world cooking method, oil frying method is widely used among others methods such as roast, baking, and grilling regarding to the contribution of good taste, attractive color and better presentation of the food. Popularity of this method is increasing; the accumulation of waste cooking oil (WCO) generated is increasing as well (Kulkarni and Dalai, 2005). In European Union (EU) alone, WCO is annually generated approximately 700,000-1,000,000 tonnes in 2005, while Asian countries such as China, Malaysia, Indonesia, Thailand, Hong Kong, India, etc. produced approximately 40,000 tonnes per year (Razali, 2005). Currently, the increasing of population and the extent at which consumers employ frying method in preparing food resulting in generating huge amount of WCO worldwide. Management of WCO has recently become a serious challenge in both developed and developing nations (Cvengroš, J., & Cvengrošová, Z. 2004, Azman, A. et al,.2012). The higher the amount of cooking oil used in food preparation, the more the possibility of generating huge quantities of WCO (Phan & Phan, 2008). WCO has nowadays been reckoned which are daily generated from various sources comprising households, restaurants, catering establishments, and industrial kitchens. According to Chhetri et al (2008), a greater quantity of WCO generated all over the world is being released into the environment and Kheang et al (2006), also reported that, Malaysia alone, around 50,000 tons of WCO daily generated from vegetable oils and/or animal fats are disposed of to the environment without proper treatment. Malaysia, as the world second largest producer and first exporter of palm oil generates around 0.5 million tonnes of WCO annually Yaakob et al., 2013). Hence, the country has the potential to sustain its recently established WCO collection and recycling centres at strategic places in various cities and towns.

1.1 Reuse and Impacts of WCO

Reusing WCO by continuing heating and consuming reported to be very dangerous to human health which includes the risk of cardiovascular diseases, liver problem, and cancer. When cooking oil is subjected to persistent heating, the concentration of the hydrocarbons in the oil is more condensable and makes it unhealthy for human health (Kulkarni et al., 2006; Jaarin & Kamisah, 2012; Hanisah & Tajul, 2013; Schiffman, 2000).

In addition, the repeated usage of WCO is hazardous to consumers because the fried oil forms toxic compounds such as peroxides, aldehyde and polymer through several reactions such as thermolytic, hydrolysis, and oxidation (Kulkarni and Dalai, 2006). Thermolytic reaction occurs when there is no oxygen at high temperatures above 180 °C. Although WCO is known to be a carcinogenic element, it can be used as value-added products such as biodiesel, lubricants, biopolymers or soap. Many local communities are not aware of the danger. Due to the lack of knowledge of WCO management, a step must be taken into consideration to overcome it.

In some countries, waste cooking oils are recycled and utilized as alternative ingredients or materials. The main use of recycled WCO is in the production of animal feeds and in a much smaller proportion in the manufacture of soaps and biodegradable lubricants. Some health risks can be traced from the use of recycled cooking oils in animal feeding, such as undesirable levels of contaminants, particularly PAHs (Polycyclic aromatic hydrocarbons), PCBs (Polychlorinated biphenyls), dioxins and dioxin related substances (Riera et al, 2000). By consumptions of animal origin foodstuffs like milk, meats, poultry and other products, these undesirable contaminants enter the human body and cause serious long term health hazards. As these contaminants are liposoluble, they accumulate in organic lipids and finally in the body, and thereby their concentration increases gradually over the years. In other words, the body is exposed not only to a single acute action, but also to a chronic action of bioaccumulation of these hazardous compounds over the years (Rieraet.al, 2000). Hence utilizing the recycled WCO in any way is not advisable from health standpoint. Besides the health effects of these WCO, their disposal could also have a large environmental implication because of high COD (Rieraet.al, 2000). Aside from the above-mentioned application of recycling WCO, WCO utilized as an alternate feedstock in biodiesel production. Several researches along this direction have been conducted around the globe (Arjun et al, 2008; Canakci, 2007; Khalisanni et al, 2008; Zhang et al, 2003; Sudhir et al, 2007).

In order to reduce environmental and health impacts, collecting and recycling WCO is among the most common practice in developed countries or regions like the EU, Japan, United States, and Taiwan (Jaruyanon & Wongsapai, 2000). The collection and recycle of WCO for production of some valuable products are including the production of soaps, energy by anaerobic digestion, thermal cracking, and recently the production of biodiesel. Countries like China, Thailand, Japan, Taiwan and Singapore are also engaged into WCO collection and recycling for biodiesel (Jaruyanon & Wongsapai, 2000; Zhang et al., 2012).

1.2 Discharge and Management of WCO

Discharge of WCO into waters alter the oxygenation process (DO) and destroy the aquatic lives in the environment by forming a layer which covers the water surface and prevents oxygen dissolution. When the by-products of oil degradation mixed with water, it will increase the chemical oxygen demand (COD) and biological oxygen demand (BOD) of the water. Consequently, the aquatic lives absorbed poisonous compounds from the polluted water and later returned to human through food chain (Kulkarni & Dalai, 2006). On the other hand, when the WCO solidifies and accumulates inside the drainage system causing blockage the drain resulting in several operation and maintenance problems which effecting to economic development. Once sewage is blocked by oil condensation, it causes sewer backups and overflows into surrounding environment causing potential environmental health hazards and an extra cost for clean-up efforts (Chhetri et al., 2008; Schiffman et al., 2000; Carlos et al, 2011).

Waste cooking oil which is expected to be treated and managed in a manner that could not be detrimental to the human health and/or the environment, is being disposed of by consumers via sinks, waste bins, drainage systems, toilets, or directly to the immediate water bodies and lands. According to Chhetri et al., (2008), a greater quantity of WCO generated all over the world is being released into the environment. This act in the long run contributes to water and soil contamination, causes aquatic life distraction, sewer system blockages and overflow, increases water treatment and waste management cost, and consequently generates undesirable impacts to the entire environmental system (Chen et al., 2009).

WCO management aims at preventing the general environmental and health effects associated with its improper disposal and continuing consumption among users (Korbitz, 1999). Improper waste management of cooking oil leads to discharge of WCO to environment and this will cause environmental pollution particularly land and water pollution. In water, oil layer covers the surface and prevents the dissolution of oxygen, thus causing a mass extinction of marine biota. Besides, the mixture of oil and water increases the chemical oxygen demand (COD) of water and causes it to be poisonous due to the presence of oil degradation by-products. Carcinogenic compounds are absorbed by the sea creatures and returned to human through food chain (Kulkarni and Dalai, 2006; Jafari, 2010; Marjadi and Dharaiya, 2010).

1.3 Recycling of WCO

WCO recycling has been in practice for decades in developed countries and regions such as the EU, Japan, United States, and Taiwan (Zhang, Y., 2012). In Malaysia, some recycling companies were contracted not long ago by some local authorities in order to collect WCO from various sources so as recycle into biodiesel. WCO especially from the fry process is among the liquid residues generated daily in most households, restaurants, catering establishments, and industrial kitchens (Kheang, L. S., 2006].

Some studies revealed the environmental and health effects associated with WCO makes some consumers to get rid of it through sinks, waste bins, drains, toilets, or directly to the immediate water bodies and soils. This practice at long run contributes to water pollution, soil pollution, marine ecosystem distraction, clog of drains, and consequently generates negative effects to the environment and results to an increase in water treatment cost (Kulkarni, M. G. and A. K. Dalai, 2006). There are quite a lot of end-uses for the WCO, which include production of soaps, energy by anaerobic digestion, thermal cracking, and recently the production of biodiesel. Recycling of WCO to biodiesel is simple, economical and sustainable way of abating its associated problems (Gui, M. M., 2008), and offers an advantage of not interfering with food resources.

1.4 Current situation of WCO in Cambodia

In Cambodia, there is no much information about WCO, it seems most of restaurants’ and households’ waste cooking oil is being disposed to either drainage or sinks, or disposed with other waste to landfill if it remains in small amount. This way might cause substantial drainage and edaphic pollution, and could block the sewage system and if the amount of WCO is high it is sold to second users or for recycling. Unofficially, some WCO from restaurants might be sold to street food shops and snack vendors for the complete use causing concern over human health risks (Bun et al., 2016). In Japan, most of residents in urban cities are solidifying WCO and disposing as incinerating waste, wasting valuable recyclable energy source. In local areas, the disposal of WCO to drainage is commonly practiced causing deterioration in sewage system (Haruhiro et al., 2013). Even, WCO recycling is a good practice for environment and health, but not economically matched, due to the high labour costs for collection, transportation and recycling processes in Japan.

Throughout Phnom Penh, there are many sources which are generating WCO such as restaurants, supermarkets, fast food restaurants, street food services and others. The increasing of cooking oil consumption resulted in increasing of waste cooking oil (Phan & Phan, 2008). Recently, numbers of restaurants are increasing due to urbanization, rapid economic development and rapid population growth. Presently, the migration of people to the capital for work and study causing the number of restaurants has been established. In Phnom Penh, there are 1.87 million in 2018 which is around 11.5% of the total population in the whole country. Furthermore, urbanization has increased 2.13% from 2010 to 2015. All mentioned above has strong contribution to high waste generation both liquid and solid. There are different types of solid waste generated in Phnom Penh, so far, waste cooking oil is challenging to be considered related to usage, storage, disposal, recycling and other benefits on economic and environment.

At present time, there is no clear information on how much cooking oil consumed, how much WCO produced, the way of storage and dispose and recycling activities are showed. So it is very crucial and urgent to start the survey on it. The research study focuses on how to store, dispose, recycle of WCO and daily amount of cooking oil used and amount of WCO generated. There are various restaurants which produce a lot of waste cooking oil, but fast food restaurants, street vendor and CP supposing to produce more WCO among all. Hence, fast food restaurants, street vendor and CP were selected for this research study. Seven Khans were selected as study areas because they are more populated and others already studied by students group from department of environmental science of RUPP in 2017 (Street vendor and CP not included).

2. Methodology

A survey has been conducted to assess the generation of WCO in the selected major food services in Phnom Penh. Moreover, the utilization and disposal practices of these establishments have also been surveyed. The survey is to evaluate the generation and disposal of the WCO as well as the list of major food services is presented in the following.

2.1 Study Area and method

This survey was conducted in six Khans (districts) to study on current situation of WCO management for food services such as fast food restaurants, street vendor and CP, and to estimate the amount of cooking oil used and WCO generated in daily pattern and how they dispose their WCO. The survey was conducted in August to September 2017 by gathering information about daily rates of cooking oil used and WCO generation, collection and disposal practices. Questionnaire survey was conducted to know the attitude, awareness, storage and disposal method regarding to WCO management. Open-ended questions were used to interview respondents who are work closely with WCO management of food services in Phnom Penh city, Cambodia. Personal information such as gender, and occupation of participants was recorded for further information.

Figure 1: Location of food services selected
Fig 1

2.2 Sampling and Sample selection

Fast food restaurants, CP, and Street vendor were selected for this study because they are the main sources of using cooking oil and generating WCO. All Khans mentioned above were selected because they are more populated and there are more food services among others. However, there were some challenges related to sampling sites, so we decided to selected samples with voluntary pattern. It means that if they are happy to join and to cooperate we selected. Google map was also used to search for the location of each. Actually we planned to select food services more than twenty but due to lacking of participation, we had selected sixteen food services for our study.

2.3 Data Collection

From August to September 2017, collected data using structured questionnaire from sixteen food services in Phnom Penh were stratified and selected based on the proportion of the total number of food services in each khan. In accordance with the food services differences samples was drawn from 7 Makara, Daun Penh, Chamkarmorn, Meanchey, Toul Kork and Sen Sok. WCO measurement was selected from four fast food restaurants, two CPs and two street vendors for consecutive two weeks.

There are two kinds of data collected 1) primary data collected by using questionnaire and WCO measurement, 2) secondary data collected from available sources such previous studies, ministries, departments and other institutions. The questionnaires were completed with the one who are working closely with management of restaurants and WCO management as well (means that the one who knows about storage, disposal of WCO, they might be manager or staff). The questionnaire used for this study was designed in Khmer languages. The contents of the questionnaire cover socio-demographic information, awareness on the significance of WCO recycling, attitude and practice regarding reuse and recycling of WCO. Number of persons in each source, number of guests per day, amount of cooking oil used, amount of WCO generated and amount of oil absorbed in food were evaluated. For WCO analysis were conducted for consecutive fourteen days to know daily rates of cooking oil used and WCO generated, collection and disposal practices of WCO. The purpose of fourteen days of measurements is to minimize the error and make more accuracy. The WCO management issues are included the quantity of cooking oil consumed and WCO generated, WCO reuse, recycling and disposal means.

2.4 Data Analysis

After the data collected from both questionnaire and WCO measurement, it is very important to properly analyze the data with program that is convenient. Microsoft word and Excel were used for data analysis. Qualitative and quantitative statistics were then used to explain socio-demographic background, practice regarding reuse, recycling and disposal of WCO, awareness on WCO recycling and attitude towards WCO management practice. Numerical data analysis by using Excel to know the amount of cooking oil consumed and amount of WCO produced and to analyze the relationship between factors effecting amount of cooking oil consumes and amount of WCO generated with t-test, ANOVA and others for two or more variables.

3. Results and Findings

WCO resulted from cooking of foods by food cookers, food manufacturers and catering establishments such as fast food restaurants, CP and street vendors. This waste is an important waste management concern since it poses some disposal problems and possible contamination of water and land resources (Arjun et al, 2008).

Table 1: Sample distribution of each location
Location	Percentage (%)
7 Makara	6.3
Daun Penh	12.5
Chamkarmorn	18.8
Meanchey	18.8
Toul Kork	18.8
Sen Sok	25.0
Total	100.0

3.1 Location of samples

Table 1 shows the sample distribution of the study area. In accordance with the food services differences samples was drawn from 7 Makara (6.3%), Daun Penh (12.5%), Chamkarmorn (18.8%), Meanchey (18.8%), Toul Kork (18.8%) and Sen Sok (25%).

3.2 Number of guests go for food services

Figure 2 · Daily guests go for food services

A survey was conducted to determine the generation, utilization and disposal of used cooking oil in selected major food chains and restaurants in Phnom Penh. From 25 food services identified as respondents for the survey, there were only 16 food services positively participated in the survey. Figure 2 shows the daily guests go for food services. Numbers of guests go for food services are higher at the weekend and on holiday. However, fast food restaurants show that 6%, Street vendor 3% and CP 2% higher at the weekend than working day. Number of people are using street vendor and fast food services are high accounted for 130-150 people on working day and 180-190 people at weekend while CP has low number accounted for 60 people on working day and 80 people on weekend (Figure 2). Based on this result it is indicated that people might like go to eat outside during weekend and holiday.

3.3 Amount of cooking oil used by each type

Figure 3 · Amount of cooking oil using by type of food services

Figure 3 shows the volume (in liter) of cooking oil consumed in a day by the sources. Amount of cooking oil using is different from one to another. The total volume of cooking oil used on daily basis as determined in the survey conducted is in the range of 14-18 liters/day. Street vendor use cooking oil the most, this might be due to the foods they made such as crickets, birds and others that need more oil than other kinds of food. CP and fast food restaurants use chicken and potato, so amount of cooking oil using is less than street vendors, but it is not much different. So type of food is effected to amount of cooking oil.

3.4 Amount of WCO generation

Figure 4 · Amount of WCO generated (l/day)

Figure 4 shows the volume in liter of waste cooking oil (WCO) generated in a day by each source. Amount of WCO generated is different from day to day especially on working day and at the weekend. Average amount of WCO generation was high for CP followed by fast food restaurants accounted for 3.7 l/day and 3.4 l/day respectively and street vendors produced the lowest accounted for 1.15 l/day. WCO generation from street vendor is much lower compared to others. This might be caused by the way of consumption such as using many times or not changing the oil but add up and up. Amount of cooking oil correlated to the day, at the weekend and on holiday and also number of guests.

Table 2: Types of cooking oil used
Categories	CP	Street Vendor	Fast Food Restaurant
Soya + Vegetable (%)	14.0	0.0	43.0
Vegetable (%)	86.0	100.0	57.0
Olive (%)	0.0	0.0	0.0
Sesame (%)	0.0	0.0	0.0

3.5 Types of cooking oil and reason to use this kind

Cooking at a high temperature has impact on health because oil can be oxidized easily which forms free radicals and compounds which are harmful to human health. So type of oil with more stability and not easily oxidized is a good choice, so oils that are high in polyunsaturated fats should be avoided for cooking (Mpiima, 2017). Table 2 shows the types of cooking oil they are using. Even type of cooking oil they are using is different from one to another, normally Soya and Vegetable oil are the most common. However, fast food restaurants use oil required by the company, while street vendor and CP use cooking oil according to price. High percentage of CP (86%) and Street vendors (100%) use vegetable oil because it is easy to find and it has lower price, while fast food restaurants has 57%.

Table 3: Reason to use type of cooking oil
Reason to use	CP		Street Vendor	Fast Food Restaurant
Reason to use	Soya	Vegetable	Vegetable	Soya	Soya +Vegetable
Price (%)	-	-	100	-	-
Quality(%)	-	50	-	-	-
Easy to find(%)	100	50	-	-	-
Requirement(%)	-	-		100	100

The reason of using the kind of cooking oil mentioned in Table 3 indicated that street vendor using vegetable oil because of price (100%), and CP shown that because of quality (50%) and easy to find (50%), while fast food restaurants use soya and vegetable oil because of requirement by company (100%). Not only type of cooking oil effect to human health and environment, but also the way of cooking is the case such the heating and using frequency.

3.6 Relationship between number of guests and amount of cooking oil used, WCO generated and oil absorbed in food with evaporation

Table 4: Number of guests, amount of cooking oil used, WCO generated and oil absorbed in food (l/source/day) and [l/person/day]
Type of Food Services	Number of Guests (person/day)	Amount of oil using [l/person/day]	Amount of WCO generated [l/person/day]	Amount of oil absorbed in food and evaporation [l/day]
CP	71	13.9 [0.196]	7.5 [0.107]-54%	6.3 [0.089]-45%
Street Vendor	165	17.5 [0.106]	10.0 [0.061]-57%	7.5 [0.045]-43%
Fast Food Restaurants	159	15.1 [0.095]	8.4 [0.053]-55%	6.8 [0.042]-45%

Table 4 show the relationship between number of guests and amount of oil used, WCO generated and oil absorbed in food, the amount was calculated as liter per source per day and as liter per capita per day. The result shows that street vendors have the highest amount among three and CP is the lowest one. Amount of cooking oil used, WCO generated and cooking oil go to food were measured in two consecutive weeks by daily measurement in order to know the variation of each stage. Table 4 shows the variation of each stage. Amount of oil using for CP is the highest (0.196 l/person/day) followed by Street vendor (0.106 l/person/day) while fast food is the lowest (0.095 l/person/day). Based on one way ANOVA test indicated that p-value (0.012) is lower than 0.05. So number of guests has correlation with amount of oil used, WCO generated and oil absorbed in food per source per day, it means that more people more oil, more WCO and more oil absorbed in food. However, it is contrast as person per day. It means that amount of oil used,

Table 5: Frequency of changing cooking oil for food services
Type of Food Services	Frequency of changing new cooking oil
Type of Food Services	2 days (%)	3 days (%)	4 days (%)	7 days (%)
CP	12.5	25.0	-	6.3
Street Vendor	-	12.5	-	-
Fast Food Restaurant	-	31.3	6.3	6.3
Total (%)	12.5	68.8	6.3	12.5

3.7 Frequency of changing cooking oil for food services

Table 5 shows the frequency of changing new cooking oil of food services, means that percentage of changing cooking oil of each kind. This table shows that most of the food services change their cooking oil within three days consisting of up to 68.8% followed by 2 days and 7 days with 12.5%. The way of using is effected to WCO generation; more importantly it is affected to human health because if they use cooking oil many times making it lower quality (Morrison, 2006). Utilizing the recycled WCO in any way is not advisable from health standpoint. Besides the health effects of WCO recycled, their improper disposal could also have a large environmental implication, because of high COD (Rieraet.al, 2000).

Table 6: Methods of storing WCO for each source
Type of Food Services	Material to store WCO
Type of Food Services	Metal container (%)	Plastic container (%)	Others (%)
CP	90	10	-
Street Vendor	88	12	-
Fast Food Restaurant	93	7	-

3.8 Storage and disposal of WCO by each source

Figure 5 · Amount of WCO sold per week as litre

Normally metal container is used to store WCO because it is simple, free and easy to use. On the other hand it is left after finishing the oil that why most of the sources using metal containers. Table 6 shows the manner in which the WCO is stored with the details of it.

Figure 5 and 6 show graphically the manner in which the WCO is disposed by the establishments and the price of WCO. As shown in the figure, all of them sell their WCO generated to buyers. But it is not clear whether these buyers bought the WCO from all establishments for what purposes. Besides selling, we are not sure how many of them still directly dispose/throw in part of their WCO via kitchen sink/canal/drainage. Normally WCO was sold within one week with various price as mentioned in Figure 6. However, fast food restaurants produced WCO the most during one week up to 42 l/week (6 l/day), while the rest produced with similar amount accounted for 23-24 l/week (3.4 l/day).

Figure 6 · Price of WCO sold as riel per litre

The price of WCO differ from one place to another except fast food restaurants ranging from 1200 to 4500 riels per litre, but fast food restaurants need to sell their WCO to their own company. The average price for fast food restaurants are half of CP and street vendor (see Figure 6). The reason is not clearly stated. But may be due to different buyers with different price.

4. Discussion

A survey of waste cooking oil (WCO) management of food services in Phnom Penh, Cambodia was carried out. The research was conducted by selecting food services from three categories which include C.P. Cambodia Co., LTD, Street vendor and fast food restaurants. The samples were selected from six Khans which are 7 Makara (6.3%), Daun Penh (12.5%), Chamkarmorn (18.8%), Meanchey (18.8%), Toul Kork (18.8%) and Sen Sok (25%). A survey conducted to selected major food chains and restaurant in Phnom Penh revealed that a considerable volume of used cooking oil is generated. It is also revealed that majority of the establishments under survey are basing on the number of times the cooking oil is used in determining that the oil should not be used anymore and should be disposed. Further, majority of the establishments sell the WCO generated to second buyers.

Based on the result from questionnaire shows that 55% of respondents are women and the amount of cooking oil consumption and WCO generation were asked, however, the confirmation of the result was found out by the measurement of each source. And the amount of cooking oil used and WCO generated is differed from one to another depending on the way of cooking and frequency of changing new oil. WCO was generated higher on weekend and holiday than working day. Medium size restaurants generate more WCO than other kinds of restaurants (large and small) because most people can afford for medium restaurants, so it means that more food are served with more WCO generated.

Cooking oil was changed every three days for all sources which is up to 68.5%, 2 days (12.5%), 4 days (6.3%) and 7 days (12.5%). The consumption of cooking oil more than once poses threats to human health, which can lead to diseases such as heart diseases, stroke, Parkinson’s disease, Alzheimer’s disease, liver and other diseases (Morrison, 2006). The survey also revealed that 100% of the sources sold their WCO to second users. In terms of health awareness, it was found that 80% of the food services used the WCO 2-3 times before disposing it, while 20% of the rest used 4 times and 7 times. So some establishments are not aware or ignore about impacts caused by using WCO many times.

5. Conclusion

Number of guests used each source indicated that at weekend more people go to food services. The amount of cooking oil consumption and WCO generation were measured, the result was 13-18 l/day and 7-10 l/day respectively. Anyway, storage and disposal of WCO were well managed by keeping in plastic container 7% and steel container 93%. And WCO was generated higher on weekend and holiday than working day.

In an attempt to raise awareness and generate information that would be helpful in improving the WCO management among establishments, a survey was conducted to determine the reuse of WCO, WCO recycling status, disposal means, awareness on WCO recycling significance. The findings from this study revealed that the WCO management of the three establishments is well managed; however public awareness campaign is still necessary in order to encourage them to more effectively manage their WCO. The awareness campaign should put more emphasis on the direct and indirect effects of improper disposal and continuing reuse of WCO in food preparation after usage of two or more times. A comparative study with different populations would assist in generalising our conclusions. Organisations responsible for managing WCO will benefit from additional empirical studies among communities in other parts of Cambodia.

Acknowledgments

This research was carried out under the supported fund of Royal University of Phnom Penh (RUPP). I would like to give profound thanks to RUPP for make this program happen. And special thanks to Research Office for coordinating and supporting for all documents processing, especially to Dr. Sok Serey for mankind reviewing all reports and Mr. Thou Reno, Chief of Research Office, for helping all the time.

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