Millions of bags are consumed every day and hundreds of billions bags per year worldwide. The raw material of manufacturing these widely used carrying bags comes from both natural and synthetic petrochemical sources. Natural fibre like jute, coton, hemp etc have been used for hundreds of years for making carrying bag. But after the invention of synthetic plastic bags made from petrochemical products like Polyethylene & Polypropylene, the use of natural source made carrying bag reduced dramatically. And finally, it has lost its popularity. Plastic bags were first introduced in 1977 and now accounts four out of every five bags handed out at grocery stores. These bags are highly functional, efficient, cheap & light but these synthetic fibres are not environment friendly. The widely used plastic bags do not degrade to environment & gradually it deteriorates biological cycle making the world difficult for living. Every day the earth is being piled up by huge amount of synthetic non degradable garbage which became the most important concern of recent times. Recycling of the used plastic bags are a way to minimize the pollution but recycling deemed to be less efficient way that creates a huge CO2 footprint. Researchers also have claimed to invent biodegradable plastic bag but it is also controversial as the process required special condition and rate of degradability is too much low. So to save our world again need to return to natural carrying bags. Among the natural fibre Jute is the cheapest fibre that has sufficient strength. It can be a good alternative of synthetic polyethylene bag.
Bangladesh is the opportunity gainer when western consumers leave plastic bags .This is helping to revive the traditional jute industry in Bangladesh.
As daily used product, carrying bag needs to be cheap. To make a cheap natural carrying bag the raw material also need to be cheap and available. Jute is the cheapest and widely available among the natural options. As Jute is manually harvested, it is a labor effective cultivation system. Jute grows mainly in Bangladesh, Pakistan, India, Thailand mostly Asian countries where labor cost is low. For this, the cheap jute can be used as the alternative of polythene to manufacture environment friendly carrying bags.
- Biodegradability & Sustainability of Jute
Jute (Corchorus capsularis & Corchorus olitorius) is a natural vegetable fibre second to cotton in importance. Jute has various environmental advantages when compared to synthetic competing products. Jute plants require minimal amounts of fertilizer and pesticides compared to other crops and jute cleans the air by consuming large quantities of greenhouse causing CO2.
Jute is a renewable energy source with a high production per hectare. The biological efficiency of jute farming means that jute agriculture has a low environmental impact compared to other crops. Jute and jute products are biodegradable, compostable, and environmentally friendly.
Here are the major environmental benefits of jute:
- Jute cleans the air: Studies indicate that, one hectare of jute plants can consume up to 15 tons of carbon dioxide and release 11 tons of oxygen during the jute growing season (about 100 days).
- Less fertilizer, herbicides, & pesticides: Relatively modest amounts of fertilizer, herbicide, and pesticides are required for jute cultivation – especially in comparison to cotton.
- Jute has high biological efficiency: Jute can be harvested within 4 to 6 months, and can produce between 20 to 40 ton of dry stem per hectare. In comparison, the fastest growing trees take between 10 and 14 years to mature. Also, trees will only produce between 8 to 12 ton, per hectare, annually.
- Biodegradability: Jute products are 100% biodegradable and recyclable. They can also be disposed of without causing environmental hazards.
Properties required manufacturing Carrying bag:
- It has high tensile strength, low extensibility,
- Jute has the ability to be blended with other fibres, both synthetic and natural, and accepts cellulosic dye classes such as natural, basic, vat, sulfur, reactive, and pigment dyes.
- Possible to manufacture trendy and reusable bag.
- Life Cycle Analysis (LCA)
Lifecycle analysis of Jute carrying bag and synthetic polythene/plastic bag enables to measure how much energy and raw materials are used, and how much solid waste, liquid waste and gaseous waste is generated at each stage of the product’s life.
- Life Cycle of Jute
Following is a lifecycle diagram of Plastic products:
In the oceans, plastic bags and other waste kill a million sea birds and 100,000 animals such as whales, dolphins, turtles and seals, each year. Once the animal’s body has rotted, the bag is released back into the sea, to kill again and again.
Only 5% of today’s bag is from recycle sources. Plastic bags have only been around since the Thirties, so no one knows how long they last. But scientists estimate they take 400 to 1,000 years to vanish.
- Some facts about Plastic bags:
- Polypropylene is a form of plastic.
- Bags are not biodegradable or compostable.
- Polypropylene is a product of the petrochemical industry.
- Non renewable resource.
- Their persistence in the environment means that they can entangle and harm marine life and other animals.
- The amount of petroleum used to make one plastic bag would drive a car about 115 meters. The 6.9 billion plastic checkout bags we use every year is enough to drive a car 800 million kilometers or nearly 20,000 times around the world .
- Plastic bags are not free to consumers – they are actually adding an estimated $173 million a year to Australia’s grocery bills.
- In the marine environment plastic bag litter is lethal, killing at least 100,000 birds, whales, seals and turtles every year.
Plastic Bags are slow to decompose and cause untold harm to wild-life.
- Reusable & Biodegradable plastic bags
According to statistics the global consumption of plastic bags is between 500 billion to a trillion annually or a million bags every minute. This huge consumption of plastic bags creates an enormous environmental problem. There are two ways of addressing this environmental problem. Firstly, if we can utilize reusable bags which have a long life span and therefore can be repeatedly reused consumption will be proportionately decreased as compared to the use of single use plastic bags. The second alternative is to use compostable or biodegradable bags.
Only one in every 200 is recycled; the other 199 take up to 1,000 years to degrade. The major number of plastic bags remain un recycled and contributing pollution to our environment. Again, the recycling process emits many toxic gases include CO2.
As an alternative to the reusable bags many companies supply shopping bags made from biodegradable plastics, bioplastics or corn starch based plastics which conform to current standards for compostability or biodegradability. While these bags may compost rapidly under certain environmental conditions, unsuitable conditions will result in more prolonged breakdown and more environmental accumulation of these bags. The anaerobic conditions existing in landfills also do not favor the breakdown of these bags. Additionally, the accumulation of biodegradable bags in litter streams will prevent recycling of other plastics with which they are mixed. There is lot of controversies regarding the efficiency of degradation of biodegradable plastic bags. “Biodegradable plastic bags” contains ingredient that means they self-destruct after a few months, breaking up into tiny pieces made of simple molecules that bugs and fungi can happily munch up. But European Plastics Recyclers Association warned that they “have the potential to do more harm to the environment than good.”
Technically it is “oxo-degradable” plastics. These are plastics made to degrade in the presence of oxygen and sunlight, thanks to the addition of tiny amounts of metals like cobalt, iron or manganese. But whether it actually happens seems to depend a lot on where the “biodegradable” plastic ends up. If it gets buried in a landfill it probably won’t degrade at all because there is no light or oxygen. Studies of one brand in the US, commissioned by the Biodegradable Products Institute, found that breakdown is very dependent on temperature and humidity. It goes slow in cold weather. And high humidity virtually stops the process, making long, wet winters sound like bad news. You might think a compost heap full of biodegrading bugs would be ideal. But a recent Swedish study found that polyethylene containing manganese additive stops breaking down when put in compost, probably due to the influence of ammonia or other gases generated by microorganisms in the compost.
So, Biodegradable plastic bags carry more ecological harm than good
- Advantages of jute Bags over Poly Bags
Jute bags are completely biodegradable, where the toxic effects of synthetics are serious that several western countries have banned it for use in food products.
Jute bags have also advantages over synthetic bags as :
more stackability, does not easily tear, re-usability, porosity, space utilization, withstand at high temperature and many more.
According to the United Nations in their report entitled Jute and Hard Fibres: Overview of Major Current Issues, jute has the following advantages as compared to non woven polypropylene.
1. Production of polypropylene fibre requires 10 to 20 times more energy than jute fibre.
2. Production of 1 ton of polypropylene produces 3.7-7.5 tons of CO2 whereas jute production has a negative impact on CO2 production.
3. Jute is a totally renewable resource whereas polypropylene is derived from non renewable resources.
4. Jute is biodegradable and compostable whereas polypropylene is not biodegradable and causes environmental accumulation of plastic and releases cancer causing compounds.
From an environmental perspective the advantages of jute as compared to polypropylene are abundantly clear there being no environmental comparison between natural agricultural crops and synthetic plastics produced by the petrochemical industry.
When it comes to financial cost however, the advantages of polypropylene are clear, though the costs to the environment may not yet be so clear. For these reasons, those corporations and organizations that choose to utilize more expensive jute products are clearly leading the way and putting the environment first.
- Comparative performance of jute and synthetic bags
A comparative study was undertaken by IJIRA to assess the comparative performance of jute and synthetic bag from end use point of view. Findings of the study has been tabulated (Table I ) where it is seen that jute bag is much superior to its synthetic counterpart in all respect except price.
Table: I (Observation based mainly on field trial performance)
|Sl.No.||Properties||Jute bags||HDPE woven bags|
|03||Storage space utilization||Excellent||Poor – Storage space utilization is affected due to low stack height (to avoid stack collaps).|
|04||Resistance for Hooking||Fair||Poor – Hook holes generally irrecoverable.|
|05||Drop Test performance (On dropping from minimum height of 16’)||Good (all bags survived)||Poor – All bags severally damaged.|
|06||Surface Texture||Rough (Suitable for stack stability)||Smooth|
|07||Operational Convenience||Good||Poor – Abrasive nature of bag causes palm injury during manual handling besides the griping inconvenience and laborers are prone to accident risks during stacking and destacking due to slippery surface texture.|
|08||End-use performance (w.r.t. bursting damage spillage and replacement)||Good||Poor – bags are prone to irreparable damage resulting in spillage and replacement|
|09||Grain preservation efficiency||Excellent||Poor – due to low air permeability and non hygroscopic nature.|
|10||% seepage of cement during field trial||1.18%||1.16%|
|11||Effect of atmospheric temperature and sunlight||Unaffected||Prone to rapid deterioration|
|14||Weight||Heavier than HDPE woven bag.||Lighter|
|15||Cost||Higher compared to HDPE bags but jute bags have attractive resale value||–|
However, it is not denying that cost of jute bag is higher as compared to synthetic bag. In fact, Sack Sewing & Finishing Deptt. of jute mills is highly labour intensive and machinery used are very old and low productive.
To be continued……