Polythene problem

Why lunch sheets should be oxo- biodegradable?
Dailymirror 2007 May 03

By Ramesh Uvais
t is four months since the ban on thin polythene came into effect, it is revealed that the use of lunch sheets has dropped drastically while the raw material use has increased drastically.
According to a survey though some four million lunch sheets were sold a day prior to the ban in January this year and today it has dropped to 2.5 million.

Industry sources attributed the cause to the use of increased raw material producing lesser volumes. For example a machine that manufactured 250 kilogrammes a day, today produces only 600 kilogrammes due to the shortage of raw materials.

Therefore the drop in sales is largely due to the want of raw material and machinery, and not because of a drop in the market.

Manufacturers said once facilities are arranged to import more machines and material they would be in a position to meet the demand.

Plastic Pakaging (Pvt) Limited Chief Mervyn Dias who has been importing degradable plastic bags to countries like Australia and England, said the raw material requirement before the ban was 38,400 kgs a month but due to the increased thickness requirement, the figure has now risen to 180,000 kgs. The overall cost of raw materials cost Rs. 21 million before the ban and now costs a staggering Rs 261 million.

Expressing his views to Daily mirror Life, Mr. Dias said there was no substitute for lunch sheets and therefore the consumption will not come down . Abanana leaf is Rs 5.00 now, but even at this price can any one supply 2.5 million banana leaf a day, he asked.

Around 300,000 sheets per day had been used for the armed services and this alone amounts to around 9 million a month, he said.

“The problem is that there is no substitute for this product . Also the households do not wash and reuse lunch sheets again for the next day as it is difficult to clean it properly. If they cannot be collected and cleaned they cannot be recycled as well.If these are collected then someone will have to washed them individually as used sheets will have oil. Can anyone do this? No, because it is difficult to collect them and even if done will have to be wash again before recycling which means the process is going to be very costly,” he said.

“Then the only solution is to make lunch sheets oxo-biodegradable. According to research done in Sri Lanka by Professor Gamini Seneviratne such sheets will degrade anywhere if there is oxygen and oxo-biodegradable bags biodegrade completely while the final product is carbon dioxide and water which disappears completely without leaving any plastic fragments in the soil . Therefore why not use biodegradable lunch sheets ? The Sri Lankan climatic condition is o.k. for degradable bags to degrade . Therefore isn't it better to make these lunch sheets biodegradable ?

“We would request the authorities to consider exempting lunch sheets from the 20 micron ban and to fix a lower thickness for lunch sheets say to about 10 microns. This will save foreign exchange and save our land also as these bags will degrade when disposed.

“There are so many advantages when oxo-biodegradable products are used because they are safe to come in direct contact with food cooked or uncooked and confirms to EC directives,” he said.

Prof. Seneviratne
Dr Gamini Seneviratne PHD Research Professor , IFS , Kandy has done extensive research about Oxo-biodegradable bags in Sri Lanka . He is probably the only professor who has carried out such research in Sri Lanka . The film used for the research was manufactured using degradable additive PDQ-H and the film was manufactured and supplied by Plastic Pakaging Pte Ltd for this testing . Plastic Pakaging Pte Ltd is a company that started manufacturing the oxo-biodegradable bags five years ago and exports to Britain and other countries . They have also carried out field testing in Sri Lanka and abroad & done extensive testing of these films abroad popularising these bags in Sri Lanka .

In an interview with Life, Dr Gamini Seneviratne said.

What is the most popular degradable bag ?
The most popular bag is the Oxo-biodegradable bag . It is popular because this degrades even in dark places , no sunlight required and the prices are very competitive .

What are Oxo-biodegradable plastics ?
Oxo-biodegradable plastics such as polyethylene HDPE , LDPE etc to which is added a degradable additive . This would accelerate the breakdown of the chemical structure of the plastic .The breakdown product are then amenable to conversion by micro-organisms, for which these products are an energy source or food , into carbon dioxide and water.

Is this a new Phenomenon?
No . The Chemistry of this breakdown is called degradation has been understood for a very long time . It involves the reaction of the plastic with oxygen in the air to form different molecules that are much smaller than the original plastic & molecules that can be wetted by water. Micro organisms can utilize these smaller , water wettable molecules as food where as they can’t use the original plastic. In conventional plastics without the additive , the degradation reaction is extremely slow taking many years more than 500-600 years .

Why is it necessary to have oxo-biodegradable plastics ?
Oxo-biodegradable plastics has all the properties like the non degradable bags , but degrade into a form that is safely absorbed into ecosystem in a certain controlled time frame . This is similar to that of natural products such as straw , leaves . There for the oxo-biodegradable bag will degrade anywhere in the world where there is oxygen degrade completely & disappear without leaving any toxic material or plastic pieces in the soil .

Are the additives used in the process harmful to people or the environment ?
No . There are no heavy metals in the additive or in the film & not harmful at all . The bags are tested for food compliance and has been approved to wrap food .

Do oxo-biodegradable bag actually biodegrade ?
Yes. We have carried out extensive research about the bag manufactured using the additive PDQ-H & we found that the film biodegrades into carbon dioxide and water The film disappears completely & finally there is no polythene fragments in the soil

Is the climatic condition o.k. in Sri Lanka for oxo-biodegradable bags to degrade?
Yes. In Sri Lanka the climatic condition is very good for oxo-biodegradable bags . The temperature in Sri Lanka is higher than UK & other countries & therefore as a result the bag degrades faster . Even the soil condition is good in Sri Lanka and ideal for oxo-biodegradable bags according to our research & tests carried out here . The bag degrades even when disposed to the landfilling under the soil as well . Why is this so important to the Environment?

Traditional plastics have excellent properties but does not degrade and this is the biggest disadvantage.