Debate: Gutter oil

Recycled cooking oil is proliferating because illegal companies make money at every stage of the process. Two experts have opposing views on a waste-to-energy solution.

Wang Jinfu

Better for engines than the table

Recent news about the food on our table has been somewhat sickening. A series of police crackdowns since July on factories that recycle used kitchen oil, or "gutter oil", illegally reflects how vicious the food-producing chain has become. To make matters worse, the illegal food-producing chain is armed with ultra-modern equipment.

"Gutter oil" is made from discarded cooking oil and kitchen waste, which come mainly from restaurants and other eateries such as cafeterias and canteens, but also from sewers.

The crackdown has helped net many an illegal operator, but an estimated 2 to 3 million tons of waste cooking oil is produced every year and part of it is certain to return to our dining tables.

We cannot and should not rely on police to prevent "gutter oil" from contaminating the food on our tables. Therefore, it would be better to turn waste oil into energy.

That waste cooking oil is toxic is beyond doubt. After being used many times in restaurants and other eateries, cooking oil produces harmful substances like fatty and trans fatty-acids, and even strong carcinogens like flavacol. Combined with the large quantities of bacteria and other dirty elements that accumulate in sewage, it is impossible to turn waste cooking oil into a non-toxic medium of cooking.

But the harmful substances that "gutter oil" carry are good material for the chemical industry. The two main ingredients of cooking oil, that is, fatty acid and grease, can be used to make fatty acid methyl ester, or environmentally friendly biodiesel - fuel made from natural, renewable sources such as new and used vegetable oil and animal fat - which can be used to power vehicles. As much as 90 percent of "gutter oil" can be recycled into biodiesel.

Biodiesel contains more oxygen and burns more thoroughly. Combustion using ordinary diesel produces 90 percent more carbon emissions compared to biodiesel. Tests show that even simple engines emit less smoke when powered by biodiesel.

Besides, biodiesel contains little sulphur, and therefore does not cause any acid rain. In fact, biodiesel is considered so precious by many developed countries like Germany and the UK that they have passed laws to mix it with petrochemical diesel and collect waste cooking oil for the industry.

But a big problem is that biodiesel producers can hardly get enough supply of gutter oil in China, because there are few qualified enterprises in the waste oil collection market. For example, there are only four in Beijing, far from enough to collect all the waste oil from sewage across the city.

An estimated 80 percent "gutter oil" in China is collected by unqualified enterprises or people, because unlike developed countries, China doesn't have many supporting policies for the biodiesel industry. This increases the cost and thus makes it hard for companies to make profit.

Biodiesel is sold at the same price as fossil diesel, that is, about 7,000 ($1,100) yuan a ton. The processing cost for biodiesel producers is about 1,000 yuan a ton, on top of which they have to pay 17 percent value-added tax as well as consumption tax of 0.8 yuan per liter. So the highest purchasing price they can afford is 6,000 yuan a ton, minimizing their chances of making profit.

In contrast, illegal waste oil factories pay no more than 300 yuan a ton for processing and don't have to pay any tax at all. Besides, they can sell the "gutter oil" as cooking oil for about 8,000 yuan a ton and, hence, can offer a price higher than 6,000 yuan a ton when collecting.

No wonder, illegal factories get the lion's share of the cooking oil waste. That's why they have become part of a vicious circle as a healthy industry withers and food scandals continue to keep us wary.

The government has to intervene to prevent the situation from worsening. It should intensify its supervision over restaurants and ensure that they sell cooking oil waste only to qualified collecting agencies, a common practice in developed countries. And considering the difficulty of cracking down on all illegal "gutter oil" collectors in China, it should subsidize the biodiesel industry to help the companies in the sector offer higher purchasing prices.

The government has indeed taken a good first step by exempting biodiesel producers from consumption tax since July. But it should exempt them from paying value-added tax, too, if it wants them to become more competitive than the illegal "gutter oil" factories in the waste oil market.

After all, the best way to suppress the illegal "gutter oil" industry is to replace it with a healthy one, especially an environmentally friendly one.

The author is a professor of chemistry at Tsinghua University and specializes in clean energy studies. These are excerpts from his interview with China Daily's Zhang Zhouxiang.

Jiang Gaoming

Joint efforts can cut profit chain

A nationwide crackdown on "gutter oil", or recycled cooking oil, is on. To prevent recycled cooking oil from appearing on our dinner tables, some people suggest a waste-to-energy transfer is better than a crackdown by police. But that is easier said than done.

The government first launched a crackdown on "gutter oil" 10 years ago, but the situation, against all expectations, has only deteriorated.

As the cooking oil scandal shows, a strong profit chain has been formed in the illegal oil processing industry: illegal operators collect waste cooking oil from sewages and restaurants and sell it at 4,000 yuan ($629) a ton to underground factories. The illegal factories then process the oil and sell it for 6,000 yuan a ton to middlemen, who then sell it to restaurants for about 8,000 yuan a ton, which is still a lot cheaper than normal cooking oil that cost about 12,000 yuan a ton.

Lured by the huge profits that can be made at every stage of the illegal process, many individuals and enterprises have joined the illegal oil recycling sector. The result: the vicious industry is growing by the day.

Some people suggest that we learn from the practices of developed countries, most of which have established a mechanism for dealing with waste oil. For instance, a law passed in Germany in the 1970s makes it mandatory for all restaurants to sign a contract with the government and keep an accurate record of every drum of kitchen garbage they produce, thus preventing waste cooking oil from returning to the dinner table.

In the US and Japan, it is mandatory for restaurants to sell (or give) garbage containing used cooking oil to only certain collectors so that it can be dealt with in an environmentally friendly way. Japanese collectors even add inedible castor oil to the waste oil they sell to prevent it from being reused as cooking oil. It, still, can be processed as biodiesel that can be used in the garbage trucks, which certainly is a healthy cycle.

Some people advise that we should emulate these examples, and help the biodiesel industry replace the underground factories. They say that because biodiesel is sold at almost the same price as petrochemical products - about 7,500 yuan a ton - the government should offer subsidies to biodiesel producers to keep illegal "gutter oil" collectors at bay.

That may be a piece of good advice but people who advise it forget how much cooking oil waste is produced in China everyday. The general consumption habit in China is to order more food in a restaurant than we can eat and create unnecessary waste, owing to which an amazingly high amount - 2 to 3 million tons - of waste cooking oil is generated every year.

The latest figure I found, shows that in April 2006, Japan's garbage dumps collected less than 1,500 tons of waste cooking oil. Small amounts of subsidy can work in countries like Japan, but China has to provide huge amounts of subsidy - a heavy burden on taxpayers - to just get things going.

Besides, even with government subsidies, it would be difficult for biodiesel producers to fight a price war with illegal oil recycling factories, for there is too big a gap between their profit margins. To raise their sales, underground factories generally sell recycled cooking oil at 8,000 yuan a ton, still about 2,000 to 4,000 yuan less than fresh cooking oil.

Once biodiesel producers enter the market, underground factories can easily raise the collection price by 1,500 yuan a ton to compete with them, something that can debilitate biodiesel producers that rely on government subsidies for survival. So promoting a healthy industry to recycle waste cooking oil for non-edible use may be a good practice in other countries, but not so practical in China.

What we should learn from the countries that have laws or regulations on recycling used cooking oil to pre-empt public health hazards is stricter supervision and detection. Instead of passing laws for collecting of waste cooking oil from restaurants, the government should strengthen supervision over the oil they use to prevent waste cooking oil from returning to the dinner table. That would be more effective and more convenient both.

No less important than detecting waste cooking oil is curtailing over-ordering, given people's consumption habit in China. That would require consumers to change their habits. Every consumer should bear in mind that each morsel or bit of food he/she leaves on the table could be used to reprocess cooking oil - that's why he/she should take away the uneaten food instead of wasting it. Perhaps the government should introduce some measures - fines, for instance - to punish people who waste food.

In other words, the problem of waste cooking oil is deep-rooted in China and can be solved only with the help and efforts of all.

The author is a researcher from Institute of Botany, the Chinese Academy of Sciences.

(China Daily 10/31/2011 page9)