Sun Valley Water & Wastewater Project
Description of Alternatives
Water Supply System Alternatives
Before the feasible alternatives for water supply could be determined, the water demand for the Sun Valley Ranch was calculated. Table 1 shows the estimated demands based off information provided by the United States Geological Survey (USGS). The gal/day/person represents the average per person (gal/min, gal, gal/load, or oz/glass) multiplied by the assumptions. To account for the maximum amount of water that will be used, the water demand includes “other uses.” The water demand will likely vary +/- 2 gallons per day.
Table 1: Water Demand for Populations of Sun Valley Ranch
Well
The first alternative for the water supply system that the team researched was the integration of a well on site. This site may require additional drilling in the event that a dry well was initially drilled and also to get past the bedrock layer because the depth of the soil is such a low value.
The well alternative would be basic with a casing, screen, pitless adapter, filter pack, and submersible pump. The pump would fill a large storage tank that would be placed near the central dome house and be connected to another pump and piping that would lead to the showers and sinks within the home.
Importation
Because Holbrook does receive its water from the C-aquifer groundwater supply and the quality meets the federal standards, importation is also an alternative for Sun Valley Ranch. No water transportation services have been identified near Sun Valley. Therefore, under this alternative, a maintenance worker with access to a truck will be hired to carry the water from Holbrook to Sun Valley. It is assumed that the truck will have four-wheel drive and have a 10,650 lb towing capacity that is representative of most Ford trucks. A 1000 gallon water tank will be placed on a trailer connected to the maintenance worker’s truck. The tank will only be filled to 800 gallons because of towing capacity. With the weight of the trailer and water storage tank filled at 800 gallons, the truck will be towing 10,605 lbs. A 5000 gallon water storage tank on the site will be filled each week. Each week the maintenance worker will make 5 roundtrips to and from Holbrook and Sun Valley.
Wastewater System Alternatives
Septic System
A septic tank is part of a soil absorption wastewater system that is underground. The tank would receive all of the wastewater from the central dome housing. Once the waste reached the tank, the solids and liquids would begin to separate. The tank would need to be pumped every 4-5 years depending on the amount of usage. Routine maintenance could allow the septic tank to reach a lifespan of 20 years.
Stabilization Ponds
Stabilization pond systems typically consist of two ponds used for primary treatment and a third for secondary treatment. They would require a significant amount of land on the site, but the area would be smaller than most stabilization ponds because they would be handling a smaller amount of wastewater. During the summer, when these ponds would be in operation on the site, algae would supply the dissolved oxygen required by bacteria. The bacteria would help break down the organic matter within the wastewater during this time. The ponds would need to be desludged at the end of October when the retreat was vacated.
Composting Toilets
Composting toilets would be designed to handle the supply of black water from about 10 people within the retreat. There would likely be about 5 composting toilets total. Graywater would be diverted into a graywater reuse system used for irrigation to prevent this additional liquid supply from disrupting the compost mixture. Assuming the human waste was properly composted and the toilet was sized correctly, the end result would be free of pathogens or viruses. After the waste was broken down to 10 to 30% of its original volume, the nutrient-rich fertilizer would be used on plants and trees, buried, or removed by a licensed septage hauler.
