Project Information

Sun Valley Water & Wastewater Project

Graywater Reuse

The graywater system will handle additional wastewater from the clothes washer, bathroom sinks, and showers. The graywater system incorporated on Sun Valley Ranch will have a flow less than 400 gallons per day and only be used for irrigational purposes [1]. There is no need for formal notification to the ADEQ or review or design approval plans for integrating a graywater reuse system on an Arizona site [1]. The storage tank for the graywater system will be covered, sealed, and securely placed near the central dome house, and it will have a connecting outlet to allow for a hosing attachment. From there the water can be distributed to the appropriate plants near the houses. When this water is distributed, it must avoid human contact and the soil that is irrigated with this gray water must also avoid human contact. The client and all residents at Sun Valley Ranch will have to carefully consider the types of substances and detergents that are used in the clothes washer and sinks to guarantee that they do not contain harmful constituents. Certain types of constituents could inhibit the quality of the graywater to a degree that would make it inappropriate to use on plants. It is crucial that no type of fecal contamination enters the graywater system. Therefore, any person that comes into direct contact with the gray water will use the appropriate protective equipment. The maintenance worker will be the only one that handles the gray water, therefore each time he transports the gray water to the tank or provides maintenance on the system, he will wear gloves. Also, at all locations using gray water on the site will be properly labeled. The team assumed that no infants would be at the Sun Valley Ranch, and that it will be unlikely that this type of contamination will occur. The suitable plants that can be fed by the graywater are citrus and nut trees along with other plants that handle the acidity of the graywater [1]. A water pump will be utilized for this system to allow water to be delivered to the high end of the garden. Also, a filter will be incorporated on the storage tank before sending it to the water.

Operation and Maintenance
After installation of the greywater irrigation system, the owner has an obligation to ensure that the system and all its components are maintained for the duration of the operation. Greywater diversion components and their related subordinate drip irrigation systems need constant maintenance. Below are some of the maintenance activities that can be carried out on greywater installations [2]:

Ensure the storage tank has a secure cover to guarantee safety and control of mosquitoes
Regularly clean and replace filters: over time, the filters get blocked with sediments hence they should be removed and cleaned and the physical contaminants such as sand, hair etc removed.
The sludge on the surge tank should be cleaned out regularly.
Check that water is dripping from the sub-surface irrigation distribution system. After an irrigation exercise, the solid around should be constantly monitored to ensure that the soil is wet
To guarantee correct readings and pump operation, the sensor should be regularly cleaned.
Evaluate the soil condition to ensure the soil is healthy. Soil that portrays signs such as unusual odors, damp, bogginess may be unhealthy.
Look for information regarding ingredients in laundry products that may be harmful to the clothes being irrigated.

Regulations
The graywater is the wastewater that stream from all sources and dealing with additional liquid waste that coming from clothes washer, sinks, and showers. This system will not include the use of water from kitchen sink, dishwasher, and toilet.
For the graywater it’s allow just when the flow is less than 400 gallons per day, can’t be accessible by the public, gray water must be used on the site where it is generated, can only be used for irrigation, and only can be used for dip and flood. In addition here are the 13 best management practices:

First and foremost, avoid human contact with graywater, or soil irrigated with gray water.
You may use gray water for household gardening, composting, and lawn and landscape irrigation, but use it in a way that it does not run off your own property.
Do not surface irrigate any plants that produce food, except for citrus and nut trees.
Use only flood or drip irrigation to water lawns and landscaping. Spraying gray water is prohibited.
When determining the location for your graywater irrigation, remember that it cannot be in a wash or drainage carrying runoff.
Gray water may only be used in locations where groundwater is at least five feet below the surface.
Label pipes carrying gray water under pressure to eliminate confusion between gray water and drinking water pipes.
Cover, seal and secure storage tanks to restrict access by small rodents and to control disease-carrying insects such as mosquitoes.
Gray water cannot contain hazardous chemicals such as antifreeze, mothballs and solvents. Do not include wash water from greasy or oily rags in your gray water.
Gray water from washing diapers or other infectious garments must be discharged to a residential sewer or other wastewater facility, unless the gray
Water is disinfected prior to its use.
Minimize surface accumulation of gray water to promote drying of soil.
Filters may be used to reduce plugging and extend the gray water system’s lifetime. If the gray water system becomes plugged or blocked, the gray water must be directed into your normal wastewater drain system.

For the reclaimed water general permit, there is no need for formal notification to department, no review or design approval, no public notice, and no reporting or renewal.

The suitable plants that can be fed by the graywater are, citrus and nut trees, rabbit brush, honeysuckle, and burning bush.

Disposal and Reuse Options

The composting toilets have strict water to solids ratio requirements, and the graywater regulations do not allow kitchen sink water to enter the system. Therefore, the kitchen sink water must be handled separately through different methods. The main concern with the water that goes down the kitchen sink drain is the risk of contamination by types of pathogens from raw meat. The water will consist of all substances washed from hands, vegetables, fruit, meat, and containers. The kitchen sink water is frequently diverted from the graywater supply because it often contains solids and grease as well. Therefore, an interceptor will be incorporated on the container that collects the kitchen sink water [3]. The kitchen sink water will be diverted into its own separate container. From Table 1, approximately 100 gallons of water will be used on the site by the 10 people per day for food preparation and dishwashing. To allow for fluctuations in this water supply, the kitchen sink container will need to hold approximately 120 gallons.

The urine that is diverted from the composting toilets will be combined with the kitchen sink water. Urine typically contains higher levels of nitrogen, phosphorous, and potassium which can helpful nutrients for plants [reference: http://www.scientificamerican.com/article/human-urine-is-an-effective-fertilizer/]. The composition of urine is typically a little strong for plants, and therefore, it should be diluted. There is the potential fecal contamination concern with the reuse of urine. However, the urine diversion system will prevent almost all potential fecal matter that may enter the urine supply. This system will not prevent 100% of any type of fecal matter because the system is simple to minimize cost. Therefore, the maintenance worker that handles the waste will, as with the gray water system handling, use the proper protective equipment when is transporting and handling the urine supply. The urine does require an appropriate dilution factor because most urine supplies have a high nitrogen and salt level [4]. The urine will be diluted with the kitchen sink supply with a ratio of 10:1 for most plants and 20:1 for seedlings and more sensitive plants [4]. The urine that is diverted from the composting toilet diversion system and the urinals will be sent to its own separate container as well. Estimating an average of 0.26 gal/day/person results in approximate volume of 26 gallons of urine/person/day. Therefore, to allow for fluctuations in the volume of urine produced per day, the container for urine will need to be approximately 40 gallons.

Referencing the water demand table, approximately 100 gallons of water will be used on the site by the 10 people per day for food preparation and dishwashing. This will be combined with the urine that is diverted from the composting toilet. Estimating an average of 0.26 gal/day/person results in approximate volume of 26 gallons of urine/person/day . Therefore, the kitchen sink and urine water supply will provide an additional 126 gallons of water per day for plants

References:

[1] Arizona Department of Environmental Quality. Using Gray Water at Home. [Online].
Available FTP:http://www.greywateraction.org/sites/default/files/laura/Sep09/ADEQbrochure.pdf

[2] S. Sharvelle et.al. (2012). Long-Term Study on Landscape Irrigation Using Household
Graywater-Experimental Study. [Online]. Available FTP: http://greywateraction.org/wp-%20content/uploads/2014/12/Long-term-Study-on-Landscape-Irrigation-Using-Household-%20Graywater.pdf

[3] Arizona Department of Environmental Quality.(2005). Water Quality Division: Rule
Clarification. [Online]. Available FTP:http://azdeq.gov/environ/water/permits/download/012.pdf

[4] Northwest Edible Life. (2013). How to Use Pee in Your Garden. [Online]. Available FTP:
http://www.nwedible.com/how-to-use-pee-in-your-garden/

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