Products are on the market that allow rainwater and graywater to be reused to flush toilets and irrigate landscaping. Unfortunately, while water recycling is allowed by the Uniform Plumbing Code, it's still frowned upon by many local codes.
The other impediment is cost. The Pontos GmbH subsidiary of Hansgrohe has a whole-house graywater recycling system that it's selling in Europe, but it has no plans to bring it to the U.S.
“For one thing, water is much too cheap in the United States,” said Michael Hasenbeck, head of Pontos' strategic division in Schiltach, Germany. “While there is very substantial interest in the AquaCycle technology, the low water price in the U.S. means that it would take far too long for a Pontos AquaCycle facility to pay for itself.”
The second hurdle is the lengthy code approval process, Hasenbeck said, and then the effort involved developing a trained dealer network.
It's only a matter of time and enough drought until such systems are in use, so this is how it works.
Gray water is processed in four phases according to the process developed by Pontos. First, a filter unit filters out larger particles, such as bits of textile or hair. The filter is electronically controlled and reversed, with the remaining particles going into the sewer system. Next, bio-cultures break down the dirt components in the water in the pre- and main recycling chambers. The water is pumped along in three-hour intervals. Sediments are moved automatically into the sewer system. Then, before the water gets to the treated water storage tank, it flows along a UV lamp and is sterilized. Afterwards, it is odorless and can be stored for the long-term until it is used again.
The company has a number of packages that recycle from 900-12,500 liters per day or 238-3,300 gals./day. According to the company, the installed cost in a new single-family home in Germany is around $6,680, plus the cost of a dual drain pipe system costing from $600-$900. The dual drain requirement, however, makes the system impractical for retrofits.
Rainwater recycling is, perhaps more immediately practical and available for sale now in the form of Jay R. Smith Mfg. Co.'s Rainwater Harvesting System.
Commonly rainwater harvesting systems are constructed of three primary segments, according to the company: 1) a collection method, 2) a conveyance component and 3) a storage facility. Rainwater harvesting collection, conveyance and storage systems can be incorporated into almost any existing site or building, although it is easier to incorporate a rainwater harvesting system into new construction.
For the first stage, a collection or catchment system is generally a simple structure such as hard roofs or gutters that direct the rainwater through a conveyance component into storage. The amount and quality of rainwater collected from a catchment area depends upon the rain intensity, roof surface area and type of roofing material. For a 1,000-sq.ft. roof, about 623 gals. can be collected per inch of rainfall, regardless of pitch. Water quality from the roof catchment is a function of the type of material used on the roof, climate conditions, and the surrounding environment. The roof material should be both non-toxic and inert.
Second, conveyance components are required to transfer the rainwater from the roof catchment to storage. Conveyance is usually accomplished by connecting roof drains and piping from the roof top to one or more downspouts that transport the rainwater through a filter system to storage in tanks for reuse or recharge.
Jay R. Smith manufactures a siphonic roof drainage system that is an effective technology for capturing rainwater from a building rooftop for rainwater harvesting. In a siphonic system, several roof drain outlets can be connected to a single vertical discharge pipe. Fewer discharge points and no requirement for pitch in the piping means the rainwater can be easily routed horizontally below the roof to a storage tank, cistern or retention pond.
Finally, storage containers or cisterns for the harvested rainwater make stored rainwater available when needed. Depending on the space available, the tanks can be constructed above grade, partly underground, or below grade. Typical containers include cylindrical reinforced steel and concrete tanks, large jar shaped vessels constructed from wire-reinforced mortar, single and interconnected tanks made of either galvanized steel, concrete, ferro-cement, fiberglass, or polyethylene, or they could be made of wood, metal, or earth. The polyethylene tanks are the most common, and easiest to clean and connect to the piping system. Storage tanks must be opaque to inhibit algae growth. They should be located as close to supply and demand points as possible to reduce the distance the water is conveyed.
Before entering the storage unit, rainwater should be filtered to remove leaf debris and other large particles. Upon leaving the cistern, the stored water is extracted from the cleanest part of the tank, just below the surface of the water, using a floating filter.
Smith also shows residential systems on its Web site that can supply both potable and non-potable rainwater. The systems can use either above- or below-ground tanks and the main difference with the potable system is that it comes with water purification components.
Additional information is available at www.jayrsmith.com/products/rainwater_harvesting/index.htm
On the scale of a single toilet, a company called WaterSaver Technologies LLC exhibited the Aqus graywater system at the Greenbuild Show in Chicago in November. The system uses a 5.5-gal. tank mounted in a vanity that feeds the tank of an adjoining toilet. Water drains out of the lavatory into the tank where it is filtered and pumped to the toilet tank. If the holding tank is full, the graywater overflows down the drain through a P-trap. When graywater is available to fill the toilet tank, the device pushes up the float on the fill valve so that it does not operate. If graywater is unavailable, the fill valve fills the toilet with potable water as it would conventionally.
The company said that it has a UPC product listing pending with the International Association of Plumbing & Mechanical Officials. Additional information is available at www.WaterSaverTech.com.