AsianScientist (Dec. 5, 2019) – In a dark alley, a van pulls up at the back door of a Chinese restaurant. Foul, obnoxious fumes emanate from the van as the driver slides the door open. He heads into the restaurant and minutes later comes out with buckets of food waste and used cooking oil. He loads this into what was once blue but is now a dirty, green plastic barrel.
Elsewhere in the city, a middle-aged woman drags open a sewage cover and lowers a large scoop tied to a bamboo pole. As she retracts the contraption, a satisfied grin appears on her sun-beaten face, and she empties the sludge into a pail. Such is the scene of gutter oil collection, a highly lucrative business in parts of China, Taiwan and possibly even Singapore.
The gutter
‘Gutter oil’ refers to waste cooking oil that is reused after being filtered. Although illegal, some unscrupulous people still filter waste oil from sewer drains, slaughterhouse scraps and other sources, then sell it on to be reused.
Through repeated high-temperature cooking, vegetable oil undergoes thermal oxidation to produce toxic chemicals, including carcinogenic free-radicals. The toxic oil has been blamed for making people sick and causing some forms of cancer, but it continues to be used because it is cheaper than fresh cooking oil.
Gutter oil was once so prevalent that Professor He Dongping of Wuhan Polytechnic University estimated that in 2010, one in ten meals in China had been tainted with gutter oil.
The problem of gutter oil is just one of the many problems associated with waste cooking oil disposal. The inappropriate disposal of waste cooking oil into sewers has resulted in the formation of a 15-ton ‘fatberg’ that almost paralyzed parts of London. “Kingston came very close to being flooded with sewage,” lamented Simon Evans, a Thames Water spokesperson, in The Guardian.
Similarly, in San Francisco, inconsiderate dumping of waste cooking oil into the sewers costs the city USD$3.5 million annually in cleaning bills.
With increasing affluence, the demand for cooking oil has steadily been increasing at about three to four percent a year, from a consumption of 167 million metric tons in 2013 rising to 197 million metric tons in 2018. With an increase in consumption comes the problem of waste oil disposal. Restaurant owners are stuck with worthless goods and must pay collectors to dispose of the waste.
The gold
Fortunately, the tide is turning, and gutter oil may have new applications that are safer than being reused in cooking. In recent years, improvements in technology, rising fossil fuel prices and increasing environmental awareness have given rise to a commodity market for used cooking oil (UCO), which is used to make used cooking oil methyl ester (UCOME), a type of biodiesel.
Unlike fossil fuels, UCOME contributes a minimal amount of net greenhouse gases, and is touted as being carbon-neutral. It is also non-toxic and biodegradable. An added advantage of UCOME over other forms of biodiesel, such as those from plant-based feedstock like soy bean or palm oil, is that there is no competition between plants as feedstock for biodiesel production and plants as food crop, thus solving the food versus fuel conundrum.
Due to the nature of UCO, the process required to produce biodiesel is expensive and laborious. The UCO feedstock is highly acidic and needs to be neutralized first. It is then run through a process called transesterification, where it reacts with methanol in the presence of a catalyst to produce UCOME. This generates large volumes of wastewater, which need to be treated before disposal.
Newer technologies, like hydrotreatment and enzymatic transesterification, have made the process more economically viable and less laborious. In catalytic hydrotreatment, hydrogen is reacted with UCO at high temperature to produce hydrotreated vegetable oil. The resulting oil is of such high quality that it can be used as jet fuel.
The other method—enzymatic transesterification—makes use of an enzyme called lipase to catalyze the conversion of UCO into UCOME. This can be done even in acidic environments, thus eliminating the need for the neutralization pre-treatment step. No further chemicals are added, so the cost of wastewater treatment is kept to a minimum.
With these technological advancements, what was once dumped into drains is now a precious commodity, so much so that under the cover of night, thieves are now stealing UCO from restaurants across the United States.
Back in China, Chinese startup MotionEco, in collaboration with Shell’s ‘Make the Future’ initiative, has launched China’s first commercial initiative to make biodiesel from gutter oil and UCO in Nanjing. Similar efforts are seen in Shanghai, where biodiesel made from gutter oil is blended with diesel in a pilot project by China Petroleum & Chemical Corporation (Sinopec), an oil and gas company in China. From 2016 to 2018, 10 million liters of this biodiesel has been sold. In this way, Sinopec has absorbed almost all of the gutter oil produced in Shanghai.
In the Philippines, the rampant discarding of UCO into sewers and the sea has driven the beaches of Barangay Sasa in Davao City almost to ruin. To clean up the city and revive its fishing industry, Philippines’ first biodiesel processing facility was built in collaboration with Biomass Japan Inc in 2017. Local businesses and households voluntarily collect UCO and send it to the facility for processing.
“Just a little bit of sacrifice in collecting the used cooking oil so Mother Earth has an opportunity to be clean,” said Juanito Flores, a resident of Davao City, in a Channel NewsAsia interview. The biodiesel plant has since proven to be sustainable, so much so that some heavy machinery now runs exclusively on biodiesel.
It is a similar tale in Malaysia. FatHopes Energy, a Malaysian biodiesel company, was launched in 2010 by Vinesh Sinha. Sinha named the company FatHopes after his dream of producing energy from fat, and to serve as a reminder of the naysayers who mocked his vision as ‘fat hope.’ He proved them wrong. By 2017, FatHopes Energy dominated 70 percent of the UCO market in Malaysia and Singapore. Between 2015 and 2018, FatHopes Energy saw demand for its UCO increase by about 40 percent.
The price of UCO has also been increasing over the years. What was once seen as junk, is now trading at a 10-15 percent premium over crude palm oil, and traders estimate it costs MYR$600-700 a ton.
Interestingly, Singapore, which has a smaller production of UCO compared to its neighbors, is benefiting from this green revolution, thanks to Singapore’s technically advanced workforce and proximity to feedstock sources in Southeast Asia.
In 2018, Neste, a global leader in renewable energy from Finland, invested S$2 billion in Singapore to build the world’s largest biodiesel plant, capable of an output capacity of up to 4.5 million tons annually.
Locally, Singapore recycling firm Alpha Biofuels has started integrating biodiesel production from UCO directly into shopping malls. Taking up a room in the basement of Raffles City Shopping Centre, Alpha Biofuels collects UCO from surrounding food outlets and hotels, such as Fairmont Singapore and Swissotel The Stamford, and converts them into biodiesel on site before transporting them to Tuas.
It seems that the solution to the energy problem may have been lying in the gutter all along.
Fueling growth
Nonetheless, despite the advantages of UCO-based biodiesel, the take-up rate has been slow. Currently, biodiesel accounts for less than four percent of transportation fuel worldwide, and of this, only 10 percent of the world’s biodiesel is made from UCO. Despite technological advancements, investing in new machines and redesigning processes are costly. Moreover, some of these advancements are protected by patents, rendering rapid adoption unlikely.
Economic incentives and policy changes might be necessary to increase adoption of such green technologies. For example, under the European Union Renewable Energy Directive, it is mandated that 10 percent of energy for transportation use should be from renewable sources by 2020. To help member states achieve this goal, biofuels made from waste materials such as UCO can be ‘double counted.’ Though such policies are not without controversy, they have nonetheless incentivized companies to use UCO as biodiesel feedstock.
In Southeast Asia, Malaysia and Indonesia have mandated the use of biodiesel in the transportation industry. Although Singapore has no similar mandate, the Carbon Pricing Act that came into force in 2019 is a positive step towards incentivizing greener alternatives.
More widespread use of biodiesel can help to turn gutter oil into a precious resource and reduce the environmental hazards associated with fossil fuel emissions. While the foundation stones have been laid, a more concerted effort by governments, businesses and individuals is still needed to achieve a significant impact for a cleaner environment.
This article won first place at the 2019 Asian Scientist Writing Prize.
Click here to see photos of the the prize presentation ceremony held on December 4, 2019.
———
Copyright: Asian Scientist Magazine; Photo: Shutterstock.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.
