Pollution of Sorted Waste Is a Problem.

Quality of Sorted Waste

The rate of municipal waste separation in Slovakia and across Europe continues to grow. This is a positive trend, yet the sheer amount of sorted waste does not guarantee successful or efficient recycling. The decisive factor remains the purity of separated materials, which is increasingly compromised by contamination.

Even a single incorrectly discarded or dirty item can devalue an entire batch of otherwise correctly sorted waste. The result is higher sorting costs, limited recycling options, and, in many cases, waste ending up in landfills or incinerators. Such outcomes are undesirable not only from an environmental but also from an economic standpoint.

Types of Contamination and Their Impacts

Contamination comes in many forms — from food residues in plastic packaging and toys containing toxic substances to greasy paper or used hygiene products. These impurities reduce the quality of recyclates and often make further processing impossible.

• Plastics: Packaging heavily contaminated with organic waste is difficult to sort. Technical plastics and toys often contain chemicals (e.g., SCCPs and MCCPs) that are harmful to health and hinder recycling.
• Paper: Greasy or laminated paper, as well as used hygiene products, are often incorrectly thrown into paper bins, contaminating entire loads.
• Polystyrene: Expanded polystyrene (EPS) is bulky, hard to collect, and often contaminated with food residues.

Such contamination lowers the quality of recovered materials, increases processing costs, and discourages recycling companies.

Why Is Contamination Such a Serious Problem?

• Technological incompatibility – Some composite materials (e.g., plastic-coated paper) are difficult to process.
• Economic unfeasibility – If sorting costs exceed the value of recyclate, recycling loses its sense.
• Higher costs for municipalities – The financial burden shifts to local governments and residents.
• Risk of missing legislative targets – Contamination lowers recycling rates and may lead to penalties.

Smart Solutions Against Waste Contamination

Although contamination is a complex issue, modern technologies offer promising solutions. AI-based and sensor-driven intelligent systems can significantly help.

1. Vision AI on Sorting Lines
2. Using AI cameras directly on sorting lines enables automatic contamination detection. In practice, this has reduced unnecessary waste transport by 30% and contamination by up to 40%.
3. Edge AI in Collection Vehicles
4. This technology analyzes the contents of containers during emptying. Real-time video analysis helps identify contaminants and optimize the sorting process.
5. Smart Bins
6. These AI-powered bins use cameras to classify waste at the point of disposal. Sorting happens immediately when waste is thrown in, greatly reducing contamination risk.
7. Predictive Waste Collection
8. A smart waste management solution that, based on waste volume and composition trends, can predict collection needs, optimize pricing, and analyze waste composition — increasing efficiency across municipal waste management operations.

AI4Waste and Popelka – Research Projects for Smart Cities

Slovak and Czech companies are leading advanced research projects in intelligent waste management.

• AI4Waste Recognition – A project focused on radar sensors that measure the cleanliness of sorted waste. These sensors detect unwanted materials (e.g., paper in plastic streams) using reflected signal analysis. Combined with video analytics, they enable even more accurate contamination identification. The main challenge remains practical deployment — particularly power supply and initial investment costs.
• Project Popelka – Already in the physical testing phase. It calculates optimal collection routes, estimates service times for municipalities, and recommends the nearest end-processing facilities. This allows for annual collection scheduling across entire regions.

A Future Without Contamination Is Possible – Thanks to Smart Technologies

Efficient and economically sustainable recycling requires clean sorted waste. Key roles are played by public education, technological innovation, and cooperation between municipalities, companies, and research institutions.

Smart technologies — artificial intelligence, sensors, and radar systems — represent hope for a future where waste sorting is not only quantitative but also qualitatively effective.

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