One of the many ways commercial facilities and hotels are reducing water consumption is to use greywater. Greywater is typically defined as “gently used” water that comes from restroom sinks, kitchen sinks, showers, etc. Facilities that use greywater are often “doubled plumbed,” with greywater going into storage tanks and water from toilets and urinals discharged into sewer systems.
While some greywater may look discolored, even “dirty,” it is usually safe and even beneficial to use to irrigate vegetation, even though it should not be used for human consumption. Because facilities that are landscaped often use more water for vegetation than anywhere else, if water can be re-used here, it can prove to be a significant water and cost savings.
Klaus Reichardt, CEO and founder of Waterless Co. Inc., which manufacturers no-water urinals, says that hotels and commercial facilities should be aware that there are some rules and guidelines they must follow to use greywater properly. Those guidelines are below.
Greywater should not be stored for more than 24 hours. After that, it will start to breakdown and may develop odors.
Avoid touching greywater. While it is known as “gently used” water, it can contain pathogens that are harmful if consumed by people.
Don’t let greywater “pool” on the surface. This can result in mosquito breeding grounds.
Elaborate pumps and filters are usually not necessary. While some plumbing will be required, as mentioned earlier, extensive or additional systems are likely unnecessary. These extra systems require maintenance, can be costly, and require more energy to operate.
Don’t over water vegetation with greywater. Irrigate vegetation with the same amount of water as with freshwater.
Install a valve system to switch between waters. The system should make it easy to switch from a greywater source to a freshwater source, just in case the greywater tank is dry.
Use environmentally friendly products. “Building owners and managers should also switch to greywater friendly products,” says Reichardt. “For instance, many environmentally preferable cleaning solutions, laundry detergents, even dishwashing detergents will not affect the pH of water so they can be perfect for greywater.”