Blackwater and Water Recycling
When the topic of wastewater recycling comes up, most experts say that you should only recycle greywater and dispose of all blackwater. Blackwater, or sewage as it�s sometimes called, is the wastewater that comes from toilets, garbage grinders, and dishwashers. This sewage is different from greywater because it contains bacteria, pathogens, and food particles, which can rot. It is also more difficult to treat than greywater. But there are also some arguments for the recycling of blackwater and how it can help your home.
Wastewater from our homes comes from many different sources. The wastewater that comes from showers, washing machines, and sinks is considered greywater because, while it has particles and contaminants, they�re not deemed dangerous. The rest of the wastewater, from toilets, dishwashers, and garbage grinders, can contain food particles, feces, and other human body fluids and is considered hazardous. This is what makes up blackwater.
Blackwater is generally not recycled, mostly because it contains so much sewage that it is hard to clean adequately for use. Yet, science has come up with systems that will recycle blackwater, most systems filtering the water enough to be used outdoors in watering lawns and plants from underground. There are even systems that will make blackwater clean enough to be potable (drinkable), but those systems are very expensive, hard to maintain, and the people who drink that water have to get over the stigma of drinking toilet water.
Blackwater Recycling Systems
The filtering system for removing usable water from blackwater is generally outside the home. Water is piped to it, and then it goes through a process before being used to water the lawn or non-food gardens via underground pipe systems. Water recycled from blackwater should never be used as drinking water or on food crops because they could still contain harmful bacteria. There are five basic steps to blackwater filtration:
Primary treatment tank � The primary treatment tank is where blackwater goes when it runs away from the home via gravity and pipes. Here, the sewage sits for 24 hours while an established colony of bacteria works to break down the bigger particles. After the 24 hour period, the settled blackwater is pumped to the secondary treatment tank.
Secondary treatment tank � When the settled blackwater is pumped away from the primary treatment tank, it goes into the secondary treatment tank. This tank is separated into three stages to help with the continuing process.
Blackwater aeration stage � The first chamber in the secondary treatment tank begins the aeration stage. This means water and air are injected into the tank at timed intervals so that the tank contents are churned. Bacteria in the tank then settle so they can feed on the sludge in the tank. When that�s finished, the water is moved to the sludge settling chamber.
Sludge settling chamber � The water that is piped from the aeration chamber ends up in the sludge settling chamber. A bacteria biomass mechanism forces sludge downwards and the partially treated water upwards to be collected and sent on to the irrigation chamber stage.
Irrigation chamber � When the water is piped out of the sludge settling chamber, it is eventually pushed into the irrigation chamber. Here, it is clarified and chlorinated, which is the last step of the process. The water can then be piped into ground irrigation systems for use in gardens.
Benefits of Blackwater Recycling
The benefits of blackwater recycling are larger than a person might think. It isn�t all about keeping your lawn watered, though that is an excellent use for the recycled water. The filtered blackwater is also good for the environment and other benefits which include:
Reduces stress on septic systems � A blackwater recycling system can take some of the stress off older septic systems which may be close to failing.
Conserves energy � Removing the harmful bacteria from blackwater costs a lot of money and uses energy from processing plants. By doing it at home on an as needed basis, you will be helping to conserve energy.
Water conservation � Using recycled blackwater to water lawns and non-food crops/gardens conserves energy. There is a lot of fresh water wasted on watering lawns and those kinds of plants.
Habitat protection � By recycling blackwater, there is less chance of wastewater seeping into natural habitats.
Plant growth � The plants that are grown with recycled blackwater rarely need any fertilizer. There are enough nutrients left in the water after being treated that plants can easily feed off of them.
Problems with Blackwater Recycling
There are certainly several advantages to working with blackwater recycling. Unfortunately there are also disadvantages that might make people reconsider when deciding to put in a blackwater recycling system. Some of these drawbacks include:
Cost � Blackwater recycling systems can be expensive - not only to install, but to maintain, and to fix if something happens to it.
Smell � While many people say there isn�t a discernable smell, there are others who claim that they can smell the system (which is mostly sewage) all the time. This can be from dying bacteria as well.
Maintenance � The system usually requires maintenance every three months or so by the company that installed it. There is usually a charge each time they come out to check on the system.
As filtering wastewater from home gets more and more popular, many people are looking to not only recycle greywater, but blackwater as well. Extracting usable water from sewage means that there is hope for the future for water filtering and recycling. If the disadvantages of a blackwater recycling system can be overcome, then the advantages of such a system can move to the next level of refiltering water.