8. Plastic Types

Here's a concise overview of the main types of plastics:

  • 1. Polyethylene Terephthalate (PET or PETE): 

    Common uses: Soft drink bottles, water bottles. Very easy to recycle and in high demand

  • 2. High-Density Polyethylene (HDPE): 

    Common uses: Milk jugs, shampoo bottles, detergent containers. Widely accepted and easily recyclable.

  • 3. Polyvinyl Chloride (PVC): 

    Common Uses: in pipes, window frames, and flooring. More difficult to recycle.

  • 4. Low-Density Polyethylene (LDPE): 

     Used for plastic bags and squeeze bottles.

  • 5. Polypropylene (PP): 

    Common uses: in bottle caps, food containers, and car parts.

  • 6. Polystyrene (PS):

    Used for disposable cups, plates, and packaging. More difficult to recycle.

  • 7. Other:

    This category includes plastics not fitting into the above groups, like polycarbonate and nylon.

The recycling symbols associated with plastics are typically numbers inside a triangle of arrows. These numbers correspond to the different types of plastics:

  • PET or PETE (Polyethylene Terephthalate)

  • HDPE (High-Density Polyethylene)

  • PVC (Polyvinyl Chloride)

  • LDPE (Low-Density Polyethylene)

  • PP (Polypropylene)

  • PS (Polystyrene)

  • Other (includes mixed plastics)

These symbols help in identifying and sorting plastics for recycling. However, it's important to note that not all plastics with these symbols are recyclable in every area, as recycling capabilities vary by location.

Recycling of plastics - overview

Separating different types of plastics in recycling facilities is a complex process. Here's an overview of how it's done and the relative ease of separation:

  • 1. Initial Sorting:

    • Manual sorting: Workers remove obvious contaminants and non-plastic items.
    • This stage is labour-intensive but crucial for quality control.

  • 2. Size Separation:

    • Materials are typically shredded and then separated by size using screens or trommels.
    • This process is relatively straightforward and efficient.

  • 3. Air Classification:

    • Light materials like plastic films are separated from heavier plastics using air currents.
    • This method is effective but can sometimes miss denser plastic films.

  • 4. Density Separation:

    • Plastics are floated in water or other fluids. Different plastics have different densities and will either float or sink.
    • PET sinks while HDPE and PP float, making this an effective method for separating these common plastics.
    • This process is quite efficient for separating plastics with distinctly different densities.

  • 5. Optical Sorting:

    • Near-infrared (NIR) spectroscopy is used to identify different plastic types based on their unique spectral signatures.
    • This technology is highly effective and can sort large volumes quickly.
    • However, it struggles with black plastics, which absorb the NIR light.

  • 6. Electrostatic Separation:

    • Uses electrical charges to separate different plastic types.
    • This method is particularly useful for separating PVC from PET.

Relative Ease of Separation:

- PET and HDPE are the easiest to separate due to their distinct densities and widespread use.

- PP is becoming easier to separate as technology improves.

- PVC can be challenging due to its similar density to PET, but electrostatic separation helps.

- PS can be difficult due to its various forms (expanded vs. solid).

- Multi-layer or mixed plastics are the most challenging and often end up in landfills.

Challenges

Contamination: Food residue or mixed materials can complicate sorting.

Labels and additives: These can interfere with identification and separation processes.

9. Aquatic Toxicity

Aquatic toxicity refers to the harmful effects that various substances can have on aquatic organisms when introduced into water ecosystems. Here's a brief overview:

  • 1. Definition:

    Aquatic toxicity is the degree to which a substance is harmful or poisonous to aquatic life.

  • 2. Types of toxicants:

    • Chemical pollutants (e.g., pesticides, heavy metals).
    • Physical agents (e.g., microplastics).
    • Biological agents (e.g., harmful algal blooms)

  • 3. Effects on organisms:

    • Acute toxicity: Short-term, often lethal effects.
    • Chronic toxicity: Long-term effects on growth, reproduction, or behaviour

  • 4. Measurement:

    • LC50 (Lethal Concentration 50): Concentration that kills 50% of test organisms.
    • EC50 (Effective Concentration 50): Concentration causing a specific effect in 50% of test organisms.

  • 5. Factors influencing toxicity:

    • Water chemistry (pH, hardness, temperature).
    • Bioaccumulation and biomagnification.
    • Species sensitivity.

  • 6. Environmental impact:

    • Disruption of food chains.
    • Biodiversity loss.
    • Ecosystem imbalance.

EU Ecolabel Aquatic Toxicity Requirements

General Principles

1. The EU Ecolabel aims to minimize the environmental impact of products, including their potential aquatic toxicity.

2. Requirements vary by product category but generally focus on limiting harmful substances and reducing overall toxicity.

Key Aquatic Toxicity Criteria

  • 1. Critical Dilution Volume (CDV): 

    • Measures the potential aquatic toxicity of a product's ingredients.
    • Calculated based on the dosage, degradability, and toxicity of each ingredient.
    • Must be below specified limits for the product category.

  • 2. Biodegradability:

    • Surfactants must be readily biodegradable.
    • Other organic ingredients must be either readily biodegradable or inherently biodegradable.

  • 3. Excluded or Limited Substances:

    • Certain substances are prohibited or strictly limited due to their aquatic toxicity.
    • Examples include phosphates, reactive chlorine compounds, and certain preservatives.

  • 4. Toxicity to Aquatic Organisms:

    • Products must not be classified as toxic, very toxic, or harmful to aquatic organisms.
    • Typically assessed using standard eco-toxicity tests (e.g., fish, daphnia, algae).

1. Detergents and Cleaning Products:

Strict CDV limits. Phosphorus content restrictions. Limitations on environmentally hazardous ingredients.

2. Personal Care Products:

Restrictions on microplastics and other persistent substances. Limits on bio accumulative ingredients.

You have finished Module 2! 

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