Background
the Four Peppers: Harry Jones, Lauren Virzi and Mario Kaluhiokalani and Amanda Madden are the head of the Greenhouse Water Reclamation Project at Campus Center of Appropriate Technology (CCAT) located in Humboldt State University. The proposed project will be in progress for the duration of 13 weeks toward the end of the 2019 Spring Semester. CCAT is in need of a way to recycle the water used for the plants in the greenhouse. As CCAT strives to be a sustainable property, hydrating plants tend to produce a lot of water loss over time. Our job is to figure out how to make this water of use.
Problem statement
The objective of this project is to design and construct a system that will recycle the water used to hydrate CCAT greenhouse plants.
Literature Review
This is a review of the available literature pertinent to water reclamation systems.
Water Reclamation Basics
The reclamation of water from sources such as wastewater, groundwater, and rainfall is a critical relief to water needs across the globe. [1] Water reclamation is a system that recycles or reclaims water. The implementation of such a system could take many shapes and forms, which is why so many different forms of this system exist. Whether the system collects rainwater, runoff, or excess water from gardens they will share many qualities within their design and construction.
Water Reclamation Concerns
There are a number of different concerns involving water reclamation. For starters, it is important to understand the path that the water has taken to ensure it maintains cleanliness. Another issue that can arise is when one may not be comfortable reusing the water as is and would prefer to have a filtration system as well. A filter, of course, means money. Money is a luxury that a lot of people do not have, such as those who would most benefit from a system like this. Other concerns include the transport of water and whether or not a pump is needed. Not only is this another expense, but also spatially can be a challenge.
Sources of Reclaimed Water
Sources of water for reclamation are: rainwater, wastewater, industrial groundwater, urban stormwater, desalinized seawater, and irrigation return water. [1]
Types of Water Reclamation
As mentioned above, water reclamation can take many forms. Below I will elaborate on the three main types. It is important to note that there are many sub categories of system types within each of these types.
Potable Reuse
For water to be considered potable it needs to go through an extensive filtration process to ensure that contaminates are at a minimum. Drinkable water has very little contaminants. One can make their own filter out of a variety of natural materials, such as sand. [2] The gravity sand filter is effective in detoxifying water.It is an opened topped and partially filled with gradient sand and gravel sizes. The water travels with downward flow. The downside of this mechanism is that it is slower and requires a large area. A gravity sand filter is also inexpensive to build.
Nonpotable Reuse
Nonpotable water is much more simple to come by, as well as to reuse. A system like this required a dual distribution system so that potable and not potable water can be transported separately. This water can be used for residential and professional. The extent to which we would filter this water is to separate debris with a screen.This water would most likely be used to re hydrate plants.[3] Separation of debris by flotation is another mechanism. That would be our main goal as to make re watering plants less intensive. Most sediment sinks to the bottom. Using that condition to our advantage, debris free water can be transported to the storage container by diverting water through an overflow. [4]. PVC Piping is one of the most common uses to transport water in water reclamation systems.[5]
De Facto Reuse
De facto reuse is when water is directed from a natural source, into the towns use, then the wastewater is returned. This is a common method amongst dry area.
Use of reclaimed water
After water is reclaimed from the sources above, it may be used for applications that do not require high quality water such as: toilet flushing, irrigation, vehicle washing. Augmentation of this water can be used for current or future needs, protecting aquatic ecosystem flows, and recharging groundwater. [6] In 2009, use of reclaimed water substituted for more than 127 billion gallons of drinking water while serving to add more than 79 billion gallons back to available groundwater supplies. Using reclaimed water for non-drinking purposes extends our freshwater supplies and ensures sustainable use of a vital natural resource. [7]
System Maintenance
To reduce the accumulation of particulate matter within a water reclamation system it is recommended to flush out the material using an increased flow rate or pressure, which should be done regularly to maintain a functioning system. The injection of chemicals like chlorine and acid into an irrigation system are often used to flush out material, however such applications go beyond the scope of CCAT's operational interests. Conducting water quality tests of irrigation water captured for criteria such as pH, biological and chemical oxygen demand, transparency, etc. would be an effective way to determine the presence of contamination and the viability of using reclaimed water for irrigation within the greenhouse.
Plant nursery trays are irrigated on top of these tables in the greenhouse behind.
- ↑ 1.0 1.1 Novotny, Vladimir, Ahern, Jack, and Brown, Paul. 2010. Water Centric Sustainable Communities : Planning, Retrofitting and Building the Next Urban Environment. Hoboken: John Wiley & Sons, Incorporated. Accessed February 20, 2019. ProQuest Ebook Central.
- ↑ Huisman, L., and W. E. Wood. World Health Organization." Slow Sand Filtration, 1974. Accessed February 20, 2019.
- ↑ Grafman, Lonny. To Catch the Rain: Inspiring Stories of Communities Coming Together to Catch Their Own Rain, and How You Can Do It Too. Arcata, CA: Humboldt State University Press, 2017.
- ↑ Aulenbach D., Shammas N.K., Selke W., Wang L. (eds) Wastewater Renovation by Flotation. In: Flotation Technology. Handbook of Environmental Engineering, vol 12. Humana Press, 2010
- ↑ "Vinyl in Building and Construction." Building With Chemistry. Accessed February 21, 2019. https://buildingwithchemistry.org/chemistry-in-bc/vinyl-in-building-and-construction/.
- ↑ Asano, Takashi, Franklin Burton, and Metcalf & Eddy. Water Reuse: Issues, Technologies, and Applications. New York: McGraw-Hill, 2007.
- ↑ Lusk, Mary. "Reclaimed Water: Frequently Asked Questions." UF/IFAS Extension Flagler County. June 29, 2017. Accessed February 21, 2019.