Waste Disposal Units And Their Negative Effects On Waterways
Studies have found that waste disposal units can use up to 16 litres of water per use, with many people using them regularly throughout the day and the advice being to run water for a minute each time to avoid clogs. Waste disposal units are a controversial piece of equipment when it comes to their environmental impacts. People find them asking themselves: do I avoid food waste going to landfill or avoid it going into the water supply? Many cities have completely banned the use and installation of waste disposal units, believing the impact they would have on water treatment systems would be overwhelming. Water is the planet’s most precious asset, so using it as a means of discarding waste is up for debate.
Where does the waste go?
Putting food waste down the waste disposal unit is easy and convenient. You wash it away and it’s gone, not to be thought about ever again. But where does it go? It goes through your septic system, into the sewer system and then to your local water treatment facility. Food waste that is too small to be caught and removed from water will go into the wastewater system, creating capacity strains. Solid waste is filtered out and sent to a digester tank, where bacteria converts the waste into biosolids. Sometimes this can then be used as a fertiliser, but often, it goes to landfill. This may be surprising to some as many think the environmental advantage of having a waste disposal unit avoids the waste going to landfill where it contributes to greenhouse gas emissions as the organic waste lets of methane.
An alarming problem with waste disposal units is what people are flushing down them. There are many dos and don'ts when it comes to what is suitable for your waste disposal unit but even people who have been using them for years don’t seem to know what can’t go down them and why it matters. Some of the most common is fats, oils and greases. These are responsible for clogging pipes, and not just yours, they can clog pipes at any point in the system. In the UK fats, oils and greases that people put down their drains build up in the sewer system and is responsible for 366,000 blockages and 5,000 floods in people’s homes each year.
The effect on marine life
Food waste disposals have been linked to nitrogen dissolving into water. There is evidence that the water put back into waterways, such as your local stream or river, affects their chemical composition and therefore can be damaging to marine life. An increase of algae blooms, that feed on the nitrogen from water waste, cause rivers and other waterways to discolour. They have also been associated with large-scale marine mortality events. An Australian study found that the eutrophic impact of putting food waste into a disposal instead of landfill is more than three times worse when it comes to what ends up back in our waterways.
Reducing the amount of food waste produced is the single biggest way to reduce the impacts that they have on the environment and our waterways. The issue of whether food waste going into landfill or into the water systems is better will be an ongoing discussion as both have their pros and cons, but waste disposal units contribute to many different environmental issues. Composting food waste is one of the better options as it avoids water consumption and reduces greenhouse gas emissions, but it seems that throwing your food waste into the bin is better than washing it down your disposal.