In a world where fresh water is becoming an increasingly scarce resource, water reuse has become an essential practice for protecting the environment and promoting sustainable development. Specifically, water used in cleaning processes offers significant potential for reuse, helping to reduce water consumption and ease the pressure on our water resources. This article explores how we can make use of cleaning water, the benefits associated with reusing it, and offers practical tips for putting this practice into effect in our day-to-day lives.
Why Reuse Cleaning Water?
- Conservation of Water Resources
Water reuse reduces the need to draw fresh water from rivers, lakes and aquifers, helping to conserve these vital resources. Since fresh water is a limited resource that is essential for life on Earth, conserving it is fundamental to ensuring its availability for future generations.
- Reduced Environmental Impact
Treating and transporting water consumes energy and generates greenhouse gas emissions. By reusing water, the demand for drinking-water treatment and distribution processes is lowered, thereby reducing the associated carbon footprint and the overall environmental impact.
- Improved Water Security
Water reuse improves water security by diversifying the available water sources, which is especially critical in regions affected by water scarcity. With more than one source of water, communities are less vulnerable to droughts, over-exploitation of aquifers and other challenges related to water supply.
- Support for Sustainable Development
Water reuse is a key strategy for achieving several of the Sustainable Development Goals (SDGs) set by the United Nations, including sustainable management of water and sanitation for all (SDG 6), sustainable cities and communities (SDG 11) and climate action (SDG 13). By reusing water, we contribute directly to building a more sustainable and equitable future.
- Economic Benefits
Water reuse can offer significant economic benefits, such as lower costs associated with water supply and wastewater treatment. For industries and farmers, using recycled water can cut operating expenses and increase competitiveness.
How Is Reuse Carried Out?
- Separating greywater and blackwater
The separation of greywater and blackwater begins at the source, that is, at the point of generation within the residential, commercial or industrial infrastructure. This involves installing dedicated plumbing systems that direct greywater and blackwater to different handling and treatment systems:
· Greywater Collection System: This system collects water from showers, washbasins and washing machines, among others, and directs it to a treatment or storage tank. Here, the water can undergo filtration and disinfection processes to eliminate pathogens and reduce turbidity before it is reused.
· Blackwater Collection System: Blackwater is directed to a wastewater treatment system where it is treated using advanced biological and chemical processes. This treatment aims to reduce contaminant levels to levels that are safe for discharge into the environment or for reuse in restricted applications.
Water Reuse
· Greywater Reuse: Treated water can be used for irrigating gardens and crops, flushing toilets and in cooling systems, among other non-potable uses. This helps to reduce the consumption of drinking water for activities that do not require potable-quality water.
· Blackwater Reuse: Although blackwater treatment is more complex, the resulting water can be used in certain agricultural and industrial applications and for aquifer recharge, provided that it meets the quality standards required for those specific uses.
- Basic Treatment
To reuse cleaning water safely, it is crucial to put it through a basic treatment that ensures it is suitable for new uses. This treatment usually consists of two main stages: filtration and disinfection. Simple, accessible methods for carrying out each of these processes are explained below:
Filtration
Filtration is the essential first step in treating cleaning water. Its aim is to remove solid particles, residues and other impurities suspended in the water. Here is how to do it:
· Using Cloth Filters: An effective and inexpensive method is to use cloth filters, such as cotton cloths, old towels or even T-shirts. Place the filter over a wide container and pour the water slowly through the fabric. This process will retain the larger solid particles. For finer filtration, you can use several layers of cloth or mesh filters with different degrees of porosity.
Disinfection
After filtering the water, the next step is to disinfect it to eliminate pathogens such as bacteria, viruses and protozoa that can cause disease. There are several methods for disinfecting water, but here we will focus on the use of chlorine, one of the most accessible and effective methods:
· Disinfection with Chlorine: Chlorine is a powerful and accessible disinfectant that can be found in the form of household bleach (sodium hypochlorite). To disinfect the water, chlorine must be added to the filtered water in a safe and effective proportion. The recommended proportion is usually 2 drops of bleach per litre of water. After adding the chlorine, stir well and leave the water to stand for at least 30 minutes before use. It is important to make sure that the bleach is suitable for water treatment and contains no fragrances, colourants or additives.
The products used can be concentrates; these contain a higher proportion of active matter, and we can use reused water to convert them from concentrate to RTU (Ready-To-Use).
At Instaquim, we have direct-action products that require no rinsing; this aspect can mean a significant saving in water consumption in cleaning processes
Important Considerations
· Safety: It is always crucial to handle chemical products, such as chlorine, with care, following the safety instructions to avoid health risks.
· Smell Test: After disinfection, a slight smell of chlorine is normal and indicates that the process has been carried out correctly. However, if the smell is very strong, leaving the water to stand in the open air will allow the excess chlorine to dissipate.
· Storage: Once treated, the water should be stored in clean, covered containers to prevent recontamination.
Where Can We Reuse It?
- Garden Irrigation and Agriculture
The most common use of reused water is for irrigating gardens, crops and green areas. It is important to make sure that the water contains no chemical substances harmful to plants or soil.
- Outdoor Cleaning
Treated water can be used for washing patios, pavements and building exteriors, as well as for cleaning vehicles. This helps to conserve drinking water for more critical uses.
- Toilet Flushing
Using reused water for flushing toilets can mean a significant saving in drinking-water consumption in homes and buildings.
- Cooling Systems in Industrial Processes
In industry, reused water can serve as cooling water in different processes, reducing the demand for new water.
- Laundry
For domestic use, especially for washing clothes that do not require drinking water, reused water can be an option, provided that it has been properly treated to remove soaps and chemical products.
Conclusions:
Water reuse, especially in a context of growing water scarcity and climate change, is emerging as an essential strategy for the sustainable management of water worldwide. By implementing treatment practices and using water consciously, at both domestic and industrial level, we can effectively address environmental challenges and secure a more sustainable future for the generations to come.