Cluster Systems and Gray Water

by Larry Losoncy, PhD

A technological revolution is happening in the world of sanitation treatment systems, and a timely one it is! The idea is simple: instead of getting rid of the wastewater coming out of our homes and offices, why not treat it and reuse it? For example, if the wastewater could be recycled for watering lawns and shrubs, the homeowner would cut the water bill and lessen the demand for water treated to a higher level of quality suitable and safe for drinking.

Nothing profound in this concept. The concept did not go very far with individual homes and smaller offices, however, because in practice it is not economical to do this approach with just one structure. The concept has proved economical with larger facilities such as schools and large plants. And now it is catching on with the cluster approach.  By clustering a number of sites on one treatment system the economics change significantly. It is by far much cheaper to run a collecting line from several homes to one nearby  treatment tank and system than to put a treatment system with each home. It is cheaper to treat a large amount of waste in one system than to treat the same amount in many smaller systems. And it is less costly by far to do the treatment right there on the site as opposed to piping the waste to a large central treatment plant miles away and then piping the recycled water back for local use.

The math works fine. The holdup in years past has been that when math hits sanitation it is no longer pure math (excuse the pun). Practical considerations enter the picture, such as where would the on-site treatment take place? How many sites would use the system (referred to as “sizing”). How would the system be managed and regulated to assure efficiency and health safety? That is where the revolution is now occurring: just treat gray water.  “Gray water” refers to waste that does not come from the toilet, the non-sanitation waste water. The most popular examples of this approach are underway with storm water runoff. As we all know, when it rains the neighborhoods create runoff because buildings and concrete prevent the rain from soaking into the ground. By diverting this water into ponds for irrigation the water becomes an asset instead of a problem. Naturally enough, some treatment is required, whether through treatment ponds or processing tanks or some combination.

When one steps back and views the big picture there is yet another advantage in treating waste on-site: it helps to reduce the danger of sanitary sewer overflow plaguing the central sewage systems of the United States. These overflow situations have a variety of causes, including flooding, line breaks, clogging of lines with grease and other materials, deteriorating systems and overloading. As early as 2004 the EPA estimated the number of these overflow incidents to be between 23,000 and 75,000 annually, discharging between three and ten billion gallons of raw sewage. Statistically speaking, this is a very small percentage of the total discharge, estimated to be 50 billion gallons per day. But in reality it is a very large amount of material containing pathogens and bacteria that cause disease and life-threatening illnesses such as cholera, Hepatitis B, stomach flu and respiratory infections.

Systems are now coming online that can mix even sanitary waste (“blackwater”) with storm water and treat all of it locally to a level that is safe as well as economical for reuse in irrigation and toilet flushing. Prospective homebuyers in new developments will be the first to hear about such approaches where they live or intend to live because these approaches are being advertised as valuable features. When environmental advances also equal dollar savings everybody wins!

Prediction: America is moving away from centralized sewage treatment plants and away from the traditional septic system. One of the next advances to be watching for will be cluster systems that separate out the sanitary waste and dispose of it through evaporation, making the rest of the wastewater easier and quicker to treat. Waterless toilets will play a part in this advance and, to the extent that they do so, the water bill will be that much less. On average about 20 percent of the water used in a typical residence is for flushing.

Some of the old sayings are once again being proven true. There really is such a thing as economics of scale. In numbers there is strength. In this case in numbers there is savings.  And yes, it is better to work together. Local is better than central because the responsibility falls closer to home! Leaks and malfunctions show up immediately. Any damage is confined and instantly addressed. The rewards are also instantly recognized and appreciated. And when the environment is the winner, so, too, are the people living in that environment.


Larry Losoncy is the president of Clean Up America, Inc. The company manufactures and markets  The Sanitizer™ non-discharge, evaporative toilet.  To learn more about The Sanitizer™ please go to