Water is one of the most overlooked aspects of conservation efforts. For instance, high process industries like energy production and manufacturing utilise enormous volumes of water. In addition, a typical commercial building or high-rise condominium also wastes a lot of water by not using a water recycling system.
Recycling or reusing water is a cost-effective way to reduce consumption and make better use of wastewater.
A water recycling system, not just for green buildings, is very relevant today, primarily because of Australia’s scarcity problem. Australia has been cursed with below-average precipitation. For example, Australia only trails Antarctica in the lowest volume of annual rain out of all continents in the world.
Yet, only a small number of buildings in Australia are redirecting wastewater for other uses.
What is Water Recycling System?
Essentially, reclamation is the process of treating what could have been wastewater and circulating it back into the system. Treatment solutions will filter and capture solids and other contaminants (either organic or inorganic) from the water.
A water recycling system is not limited to green buildings alone. You can also find such initiatives in:
● Irrigation and landscaping
● Industrial and manufacturing
● Parks and recreational facilities
● Decorative fountains and ponds
● Groundwater recharge
Of course, each recycled water requires a different treatment. Depending on the initial water quality or the application by the end-user, you may need primary, secondary, or advanced treatment.
People think that you need an excessive amount of chemicals to treat water. However, modern water treatment solutions have become more environment-friendly. For instance, they use membrane filtration systems like reverse osmosis to remove solids and other impurities. There’s also a biological treatment method to eliminate the organic matter.
Different Methods of Recycling
A water recycling system demands a mixture of technologies depending on the water quality and the intended use. For instance, using wastewater to flush toilets and urinals is considered a low-level process. There’s also grey water from your laundry or dishwashing area, which may contain organic matter, liquid soap, detergents, bleach and chlorine.
Grey water will require a different treatment process. For example, you can use activated charcoal to filter and clean the grey liquid to eliminate the organic and inorganic chemicals. Blackwater, which may contain fecal materials, involves a complex process of treatment solution or aeration and sludge settling, among others. The aerobic biological treatment uses beneficial bacteria to counteract the contaminants in blackwater. Meanwhile, membrane bioreactors are a combination of membrane and biological treatment methods.
Chlorine can also treat the water, but most service providers steer clear of the chemical since it’s not as environmentally friendly as other methods.
Implementing a Water Recycling System
A green building can utilise four methods of recycling:
1. Greywater treatment and recycling – A typical commercial building would have an abundant supply of grey water, which is considered easier to treat than wastewater. However, the water must undergo ultrafiltration before being redistributed into the water treatment system. The typical methods to treat grey water include sedimentation, flotation, or UV disinfection.
2. Blackwater treatment and recycling – Blackwater is a mixture of grey and sewage water, so it’s more complicated to treat. For instance, the water is allowed to settle in a separate tank after adding some beneficial bacteria into the fluid. Afterwards, the water will be routed into another tank with three different chambers for aeration, sludge settling, and irrigation. The last step is to add chlorine into the water. However, you can only utilise recycled water for watering lawns or decorative plants since it might still contain bacteria harmful to humans.
3. Rainwater harvesting — One of the cheapest ways to recycle is gathering free water resources through catchments and storing them in water tanks. These can be treated through UV light or chlorine in the filtration and sterilisation process. But of course, you can also use rainwater to water plants or flush toilets. Unfortunately, Australia has low annual precipitation, so this method rarely applies.
4. Recovering and reusing HVAC water – The water collected from HVAC condensation can also be recycled and reused for watering plants or cleaning water to wash surfaces. According to this study, you can collect 25 litres of water from a 2-ton air-conditioning unit.
Adopting a water reclamation program is never easy, and it should be integrated into the building plans from the start. But, first, you need to get the input of the water treatment consultants who will assess the groundwater and wastewater before designing bespoke solutions unique to your situation.
However, a water recycling system can also be installed in an old building, although it is more complicated. For example, you need ample room to store the machines to recirculate the water for reuse.
A water recycling system is ideal for places where resources are limited. However, even if you have an abundant water resource, it is your responsibility to conserve as much as possible for future generations. Besides, you cannot claim to be a green building and earn a LEED rating if you do not employ this essential requirement in the construction.