In Practice: how smart water treatment could reduce plastic waste

Developments in smart water treatment can be an important factor in the erosion of the UK’s huge waste plastic pile, explains Dave Norman of Clearwater.

Increasing amounts of plastics are reportedly being amassed by UK recycling plants after China ended its 20-year role as the world’s leading importer of UK plastic waste. Without a backup plan to turn to and with no other country prepared to take in anywhere near the amount of plastic waste that China had been importing until earlier this year, recycling plants and plastic manufacturers must draw up a new battle plan to slash plastic waste in a cost-effective manner.

With China importing 1,400,000 tonnes of UK waste plastic between 2014 and 2017, the UK was able to reduce the amount of plastic being sent to landfill. Now that the Chinese government has decided to end the importing of waste materials from overseas, UK businesses are challenged with finding alternative ways to dispose of waste plastic.

The situation may have been dubbed a crisis by notable figures in the recycling industry, but many in the UK are recognising the opportunity to reduce the use of non-recyclable plastics with a push towards creating plastics of a better quality that are easier to recycle.

Breakthrough of High-Density Polyethene (HDPE) in fighting the plastic problem

When it comes to reducing waste plastic and increasing the production of recyclable plastic, water is perhaps an unlikely resource, but it is through the clever use of water in the production of HDPE that an impact can be made.

The recycling of waste plastics into food grade plastics is one way that existing plastic can be re-used. This is made possible by shredding waste plastics such as milk bottles and separating the bottles from caps, labels and glues. However, when first introduced in the UK almost a decade ago, the end product, HDPE, was deemed too costly making demand minimal. Now, however, the demand is greater than ever before.

Once produced, HDPE is far easier to recycle than virgin plastic and water is crucial to the process of creating this plastic. Not only is water required in the hot wash that ensures the plastic is clean and safe after the plastic has been shredded into flakes, but water can also be used to reduce the amount of energy required in the heating process.

The effectiveness of turn-key pre-treatment plants

Implementing a turn-key pre-treatment plant can drastically reduce both the make-up water required, as well as the waste water generated which would traditionally have been blown down the drain, creating energy expenditure savings of 5 percent upwards, while removing the cost of draining away waste water. By analysing and optimising on-site boilers, energy savings can be made in the process of heating up the plastics during the recycling process.

Another area where significant savings can be achieved is in the cooling towers that require large amounts of water to cool the plastics down. The quality of make-up water in the cooling towers can be optimised through effective water treatment, but the system must also be analysed for inefficiencies, losses and leaks. Clearwater can also design and install bleed recovery systems to drastically reduce the waste bleed water which traditionally does to drain.

Growing emphasis on eco-friendly solid chemical treatment

The water used in the HDPE recycling process must be subjected to chemical water treatment to ensure it is clean, safe and compliant. Traditionally this has been achieved through the addition of liquid chemical solutions, typically supplied in either 25, or 250L drums that are cumbersome to transport and store making them environmentally unfriendly.

There is, however, a growing shift towards solid chemical water treatment as a far more environmentally friendly alternative to liquid chemical treatment.

Solid chemicals are supplied in smaller pack sizes that provide the same level of treatment than the liquid alternative, reducing the amount waste plastic generated by empty containers. Furthermore, the smaller solid chemical containers are created from HDPE meaning they’re quicker and easier to recycle and re-use.

Dave Norman, Clearwater