Eco-audit

Eco-audit

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Plastic grocery bags are used worldwide. Consequently, they pose a huge threat to the environment across the globe. This is because plastic bags contain a wide variety of toxic substances that are emitted in the course of its existence. The situation is further complicated by modern plastic production. The current plastic bags contain a complex structure that complicates recycling. This material is not bio-degradable. That is, it takes at least 400 years for plastic bags to disappear from the environment. These effects are minimized by a composter that turns plastic material unto carbon(iv)oxide, water, and compost. This technology is expensive and out of reach to many.  Most companies deploy aggressive P2 audit strategies for failure to discover where the waste is produced and the best management strategies. This audit addresses pollution prevention through waste reduction to improve process efficiency in grocery bags production. It also outlines recommendations and strategies to attain these and save money.

Preparation

Step 1: audit objectives

This audit provides an essential framework for effective pollution prevention and strategies to reduce the impacts of pollution on human health. All activities, products, and services within an organization that are associated with these effects are also included in the audit (How are Plastic Bags Made? 2018).

Step 2: unit operations

Extrusion- entails heating polyethylene at high temperatures

Film blowing- the molten polymer is passed through the dye and inflated

Film cutting- the films are cut into sizes and placed on spindles

Conversion- entails unwrapping the film foil and cutting with a heated knife to seal the bag’s sides.

Step 3: a preliminary assessment

The assessment outlines the relationship between the unit of operation, the substance used, and the waste products.

• Products- polyethylene, lubricants, gases, petroleum, and coal
• Toxic substances- LDPE, petroleum, coal, and gases
• Toxic usage- polyethylene is toxic when inhaled, on skin or eye as vapor.
• Point of waste generation- trimming, machinery problems, during break downs, and during blown extrusion.

In-plant facility audit and results

Step 4: defining the inputs

This step involves determining the energies used. They include (according to data retrieved from Everything you need to Know about Polyethylene (2018));

• Embodied Energy- 77-85 Mj/kg and 45-55Mj/kg (recycling)
• Molding energy- 23-25 Mj/kg
• 8300 barrels of crude oil to produce 100,000 plastic bags
• 1kg of polyethylene involve 2 kg of oil

Approximately 0.489Kw/kg of electricity is used in production.  Recycling saves electricity consumed, i.e., re-melting non-conformed or used LDPE

Step 5:  water used

About 38-114 liters of water are needed to produce a kilogram of bags. That is, 220 liters produces 1000 bags.

Water can be conserved through monitoring assessment to establish aspects of machinery that require water and make necessary changes to the flow.

Step6: Emissions

carbon footprints of LDPE amount to at least 2.6kg at production/2.7kg during recycling

• burning 1kg of oil produces 3kg of CO₂­­­­­
• _­6kg of CO₂ is produced during production and incineration
• This translates to 5 bag=1kg of CO₂

Recycling saves the amount of CO₂ generated.

Reporting and recommendations

Step 7: cheap and simple recommendation

1. Strict management of solvent requirements. If solvents are needed, a separate work table with a hood and suction system should be installed.
2. Educate society on the importance of recycling grocery bags.
3. Create a composting program for society-community and businesses.

Step 9: long-term initiative for the reduction of waste

1. Incorporate degradable substitutes for polythene grocery papers
2. Segregate and recycle grocery papers; recycling 1000kgs of grocery papers saves 16.3 barrels of oil.
3. Promote the production of re-usage grocery bags

References

Everything you need to Know about Polyethylene (2018). Retrieved from the World Wide Web: https://www.creativemechanisms.com/blog/polyethylene-pe-for-prototypes-3d-printing-and-cnc.

How are Plastic Bags Made? (2018). Retrieved from the World Wide Web: http://rutanpoly.com/plastic-bags-made/