Greywater and Water Use
Wastewater from the home can be broken down into two categories. The first is blackwater, most commonly known as sewage, and it consists of toilet wastes and wastes from food grinders/garbage disposals. The other kind is called greywater, and that comes from showers and baths, dishwashers, washing machines, and sinks in the home. Greywater is quickly becoming a way to conserve water and promote healthy reuse of water in our neighborhoods.
The Filtering Process
When greywater is being reused, it must first go through a filtering process to make sure there are no harmful chemicals and pathogens in the water that could harm the plants that could be irrigated with the recycled water. A basic system involves piping greywater away from the source to a tank, where it is treated, then stored until used, depending on where it is used. There are many filtering systems, and plenty of research should be done to discover if there is a best choice for a personal system. Some of these systems include:
Aerobic Pre-Treatment � The goal of this type of treatment is to simply remove any chunks or particles and pump the water immediately into an environment where live bacteria that purify the water can continue the treatment process. This is acceptable for places where only shower, hand washing water, and laundry water are being recycled, as the bacteria can�t break down food particles.
Anaerobic To Aerobic Pre-Treatment � This type of treatment system is for greywater systems that include large amounts of food residue, such as those piping in water used in kitchen sinks and dishwashers. This has a septic tank with three sections and a sand filter that eventually produce near-potable water for food crop irrigation.
Indoor Planter Soilbox � This style of system pipes the greywater, once it has been treated, into a soilbox where it supplies water for plants in the box. The type of plants depends on the level of treatment the greywater has been given. These are frequently found in greenhouses.
Outdoor Planter Soilbox � Very much like the indoor variety, the only difference is that this soilbox system is kept outdoors and is usually only used in places that do not have hard ground freezes during the winter.
When deciding on a system, there are obviously many choices. Anyone looking to put in a system should also check with his or her local government where some systems are approved and a rebate for putting them in is offered. Of course, planters are not the only use for greywater that has been treated and pumped somewhere else for use.
Uses of Greywater
Greywater can be reused by sending it through a filtering process and removing the particles, chunks, and bacteria it picks up when it is used in showers, bath tubs, sinks, dishwashers, and washing machines. While the water that is recycled is non-potable (not drinkable), much of it is near-potable (almost clean enough to drink) and can be used on food plants. There are many uses for greywater too, including:
- Irrigation � Recycled greywater can be used for irrigation as long as it is properly filtered, but not from washing machines or dishwashers, which contain harmful chemicals that can�t be filtered out and will kill plants.
- Non-food crops � Non-food crops and plants can be irrigated with greywater that has only been partially filtered. These include things flower beds, lawns, golf courses, and parks.
- Food crops � These kinds of crops, including farmers who grow anything that we eat, can be irrigated using greywater that has been very filtered so that it is near-potable.
- Firebreaks � In places with very high, hot, dry temperatures, many buildings and cities have firebreaks of plants. These plants can be watered with recycled greywater, as the nutrients help them grow.
- Showering/Hand Washing � Water that is recycled from showering and hand washing as well as laundry can be filtered and used again in showering and hand washing. Water that is recycled from kitchen sinks and dishwashers cannot be used for showering or hand washing.
- Laundry � Water used during lightly soiled loads or rinse cycles can be used again in other loads of laundry, because it doesn�t contain as much lint and hair as laundry water from heavily soiled loads or other parts of the washing cycle.
- Toilet Flushing � Using recycled greywater to flush the toilet can help save water immensely. As toilet flushing accounts for at least 50% of home water usage, this can be a huge savings of water. Untreated greywater should not be used in toilets, and greywater should not be used in the tanks at all.
- Car Washing � Recycled greywater can be used at professional car washes for the large amount of water used by the automatic machines.
- Water Features/Landscaping � Water features and landscaping can be watered with filtered greywater that has near-potable filtration.
- Rejuvenating Habitats � Water habitats that are running low on water can be refilled with recycled greywater. This will provide water for the aquatic creatures living there and will slowly mix into the water in the habitat, so eventual evaporation takes longer.
- Industrial Use � Recycled water can be used in industry for manufacturing purposes such as heating and cooling processes.
- Fresh Water Reintroduction � Recycled greywater that has been filtered to the near-potable stage can be pumped back into clean sources of fresh water. It mixes with the fresh water there and is then filtered and purified when more water is taken for drinking water purposes.
Benefits of Using Greywater
The benefits of using filtered greywater make the filtering process easily worthwhile. They not only save money, but water as well, and create less waste in the process. Here are some more benefits of reusing greywater for the household, all of which can help you as well as the environment around you:
- Lower fresh water use � Using recycled greywater means using less fresh water for uses that aren�t part of food growth or preparation.
- Less strain on things like failing septic systems � By having a separate piping system and filtering greywater for use, homeowners with failing septic systems can buy themselves a little more time on those systems. It can also reduce the amount of leakage in a system that does eventually fail.
- Reclamation of nutrients � Nutrients that are otherwise wasted in things like dishwater can be reclaimed with greywater recycling. These nutrients can go towards growing healthier plants.
- Plant growth � Plants that are grown with recycled greywater have been proven to grow larger and healthier. This is because the recycled water is still full of nutrients which aren�t lost in the original use.
- Reclamation of heat � There are many greywater recycling systems that use a special energy system that collects heat for the next time you want fresh hot water from the greywater that is running through pipes, sort of like hydroelectric power.
- Energy conservation � By recycling greywater, you can practice energy conservation. It takes a lot more energy to purify potable water than it does to filter greywater.
- Less chemical use � When there is less fresh water needed, there is also less chemicals needed to purify it to potable level. This saves on the amount of chemicals pumped back into fresh water sources.
- Water recharging � When greywater is used to recharge natural water sources, including both surface and ground water sources, there is eventually more fresh water to draw from when potable water is needed.
- Building development � Building in areas with very little fresh water is more feasible with greywater recycling. Less money is spent on digging wells or finding ways to pipe water to the new developing areas and more can be spent on housing.
Greywater Use and Water Conservation
Greywater use can be a large part of water conservation. The goals of water conservation include saving more fresh water for later use, energy conservation, and habitat conservation. Greywater promotes all of these goals.
- Sustainability � Greywater use promotes the sustainability factor of water conservation by reducing the amount of fresh water that is needed every day. This ensures that there is more fresh, clean water when it is needed for potable uses and that fresh water sources are consistently refilled with treated greywater that hasn�t been used a second time.
- Energy conservation � The goal of energy conservation in regards to water conservation is to reduce the amount of energy needed to process fresh water so it is potable. Reusing greywater helps with this goal because it reduces the amount of fresh water needed in homes and takes less energy to filter for a second use.
- Habitat conservation� The habitat conservation aspect of water conservation is helped by greywater reuse because it not only helps refill delicate aquatic ecosystems, but also reduces the amount of water that has to be taken from those ecosystems to fulfill the water demands.
Planning Your Own System
When planning your own greywater recycling system, there are several things you should look at before choosing a system. Knowing where you�re going to put the system, what it�s going to do, and other factors will help you choose what kind of system you want, need, and can afford, which are the three questions you need to answer.
- Current septic system � The first thing you need to learn about is the state of your current septic system. Will it handle the construction of a greywater system, and could it possibly extend the life of your septic system? Make sure that your system won�t be harmed by a greywater system.
- Where will it be placed? � The placement of the greywater system is also something you need to consider. If you�re going to put a system indoors for use with a greenhouse, you�ll need to have different piping than if you were going to put the secondary use portion outside. Systems placed outside need to be sturdier than those which are inside.
- Where will the water be collected from? � The greywater collected has a lot to do with the type of system you choose. If you are only collecting shower and sink water that has no chance of having food pathogens in it, you don�t need an intense filtering system. If you are planning to use dish water and other waters that contain particles of food, your filtering system will have to be more precise.
- What will you use the recycled water for? � When choosing your system, you need to decide what you will be using the recycled water for. If it is simply to water a decorative crop of flowers, you won�t need an as advanced system that could be used for greywater that would nurture food crops. You will also need an internal system if you want to use the water to flush the toilet, or reuse the rinse cycle water from washing machines.
- Government approved systems � Another thing to think about when choosing a system is which systems are government approved. Not only are government approved systems ones that have been tested as being better for the environment, but there are also rebates that people can get to save money after installation of these systems. It all depends on which systems are approved by your state government.
Whether you are planning a system to practice water conservation or to simply save your poor septic system some trouble, reusing greywater obviously has a lot of benefits. It is becoming more popular at the state and city level to reuse greywater, as it is less of a burden on aquatic ecosystems and saves energy. Before deciding if a greywater system is for you, remember that you�re not only helping the environment, but also saving energy, conserving water, and being a responsible consumer.