Is there a reason for greywater treatment?
Due to its origin greywater naturally contain high levels of nutrients. These nutrients originate from the soaps, shampoos, and laundry detergents that are used while cleaning. As one washes oneself or one’s clothes it is these substances that wash away dirt (germs, sweat and soil), that naturally collect on one’s skin and clothes. Greywater is thus a combination of these three substances, fresh water, soaps and dirt. It is only in special applications that it necessary to treat greywater.
How does one get rid of the germs (pathogens)?
Without getting overly scientific, there are two main kinds of pathogens found in greywater, those that require oxygen (aerobic) and those that die in the presence of oxygen (anaerobic). It is the anaerobic pathogens that may produce malodours and that could cause health complications. Both types of pathogens naturally die when all the nutrients in the water have been absorbed or when they are exposed to sun light.
How is Greywater typically used?
Filtered (direct) greywater systems are the most common. (Garden Rhapsody) Here greywater from the home in sent directly to a filter and is then pumped directly onto the lawn or used for flushing toilets. The number one rule when using greywater like this is that it may not be stored. The use of this greywater for garden irrigation is perfectly safe as it is never allowed to stagnate, since it is never stored, and is immediately exposed to oxygen and sunlight. To see how the system works click here. (Garden Rhapsody)
If it is required that greywater is stored, or if the greywater is to be used in a drip irrigation system, or reused for washing laundry and cars then it is essential that the greywater undergoes a treatment process. This treatment process is called bio-digestion.
The bio-digestion of greywater requires the nutrients in the water to be absorbed and the pathogens filtered out. This is done by making use of the pathogens natural tendency to feed and consume the nutrients in the water. Because anaerobic pathogen tend to produce malodours, oxygen is bubbles through the water, killing the anaerobic germs, leaving only the aerobic pathogens to digest the nutrients. Once all the nutrients have been absorbed even these aerobic pathogen die.
When the nutrient levels in the water have been eliminated, all that is left to purify the water adequately enough for reuse and this involves a suitable filtration process. Greywater Bio-Digestion can be seen as the artificial replication of the natural process that occurs in nature when greywater is applied directly.