How Does Recycling-Bin Contamination Cause Problems?

• Bin with contaminants
• Mould spreading
• Jammed machine
• Whole load discarded

What you will learn

• Say what contamination in a recycling bin is.
• List three ways it does harm: mould, tangled equipment and a discarded load.
• Recognise the items that contaminate most often.

Before you start

You only need to know that recycling bins are collected and trucked to a sorting facility.

What is contamination in a recycling bin?

It is something that should not be in recycling. According to UW Recycling, a contaminant is something that can degrade other materials or the recycling process. According to Pinellas County, contamination happens when residents try to recycle items that cannot be recovered in mixed recycling programmes.

A familiar example is food and liquid. According to UW Recycling, food and liquids in recycling cause mould.

• Tub with food
• Mouldy paper
• Bottle affected

In what ways does contamination do harm?

There are three main ways. First, mould eats away at the fibres in paper and cardboard, so they can no longer be made into new paper. Mould can also spread to other accepted items such as bottles and cans, lowering their value.

Second, long soft items such as plastic bags, wires, clothing and string lights tangle in the sorting machinery. That damages equipment and stops the line until someone untangles them.

Third, according to UW Recycling, when a load has too much contamination the entire load is sent to landfill, clean material included. According to Pinellas County, contamination also raises recycling costs and lowers the quality of materials.

• Wrapped drum
• Cord and bag
• Stopped conveyor

How common is contamination, and from which items?

In Pinellas County, the 2024 composition study put the contamination rate at 21.7%, about one pound in every five pounds put in collection bins that could not be recycled. That is one county's figure; other places may differ.

The top contaminants in that study were plastic bags, tanglers such as cords, ropes and hoses, foam packaging, food waste and food residue, batteries and yard waste.

Real-world example

Picture a plastic tub with leftover rice thrown into the bin on top of a stack of clean paper. This is a hypothetical walk-through to follow the consequences. The rice grows mould, the mould spreads to the paper, and if many tubs like it pile into one load, the whole load may be discarded.

Common misunderstandings

Adding an uncertain item "just in case" does not help. An item that cannot be recovered is still contamination and raises the cost of recycling.

A clean item can be contamination too. A plastic bag is not accepted by the programme, and it tangles equipment however clean it is.

Frequently asked questions

What is recycling contamination?

Something that should not be in the recycling bin because it can degrade other materials or the recycling process.

Why does food ruin recyclables?

Food and liquids cause mould, which eats away paper and cardboard fibres and spreads to other items.

When can a whole load be rejected?

When the load contains too much contamination. According to UW Recycling, a load with too much contamination is sent to landfill, clean material included.

Summary

• Contamination is anything that should not be in the recycling bin.
• It harms through mould, tangled equipment and discarded loads.
• Plastic bags, cords, foam packaging and food residue top the list in Pinellas County.