Dr. Lee Ann Clements, Dr. Nisse Goldberg, and Dr. Brian Lane have been advising a student project to improve campus and community sustainability has recently been approved for funding by the EPA.
6. Greywater Wastewater produced by bathtubs, sinks, and washing machines Low levels of suspended solids and turbidity 75% of household wastewater is grey Possible uses Car washing Ornamental fountains/ponds Irrigation
8. Our Design Residential apartment building Collect water from Washing machines Rain gutters Air-conditioning units Storage Irrigation Demonstration garden
9. Apartment Building 6 Features Conveniently located Laundry room attached Large grassy area for garden
23. s Next Steps Complete design specifications Permitting Web Site Building and installation Unveiling and demonstration
24. Rainfall Calculation Area of roof * (Avg rainfall in inches / 12 inches per foot) 6000 sq ft * (52.34 in/yr / 12) = 26,170 ft of rain/yr Rainfall in feet * 7.48 gallons per cubic foot 26,170 ft * 7.48 = 195,751.6 gallons per year Yearly rainfall / 365 days per year 195,751.6 gallons / 365 = 536.3058 gallons per day
Notas del editor
Julie - pictureSo how much water are we looking at? Part of our system requires a cistern to hold the water. But first we had to know how much water we were going to get from these three sources.
SashaFlorida has no regulations regarding storage of rainwater, but they do for laundry wastewater and A/C condensate.For 8000 gpd of laundry wastewater, we have to use a 10300 gal tank. We could use a polyethylene cone bottom tank. A tank with this capacity could weight over 2 tons, measure about 15’ tall and will have 12’ diameter. This type of tank will allow us to use gravity to distribute the water. It would have an open top with a cover on the top so that we could access the inside of the tank. This type of tank could also help us prevent anoxia, which is absence of oxygen. This is important because anoxic water could have high concentrations of hydrogen sulfide, which gives water a rotten egg smell. It could also have iron, manganese and methane, and then we would need to treat the water, making our system useless. To prevent this, greywater should be aerated, which would be easy because of the open top design. Also greywater should be stored from 24-48 hours only and with a cone bottom tank water flows easily and drains completely.During rainy season, the amount of rain might be too much for the tank to hold. We’ll use a diverter such as a valve that controls whether water comes into the tank or not. It could also be a pipe attached to the tank that reroutes water into the sewer. Diverters stop the tank from getting too full and overflowing. We might also have to use a backflow protector, a valve that lets water go from the pipes to the tank, but not the other way around. That way we wont have greywater coming back into the building.Will consider different filter options because cleaning of the filters can be time consuming and might require the use of other equipment, but they might be necessary.
This is the current project site plan. Building 6 has 26 gutters, 6 drain into the ground, and the remaining 20 drain underground into the storm sewer. It has 12 A/C units, 6 on each side. The laundry wastewater from the building goes into the WW drain. The drainfield, which is the area where the water will be filtered and absorbed into the ground, will be the on the open space next to the building. To comply with regulations, it will be about 40’x40’.
SashaThis is how the site will look like when the project is completed. We will have a 10’x10’ garden located on top of the drainfield. The cistern will be on the back so that it doesn’t block the view of the garden.
SashaTo comply with state regulations, we’ll use purple PVC pipes to take water from the WW drain into the cistern. For the rain gutters, we could use PVC pipes to take water into the cistern, or we might use gravity fed trenches to take the water directly into the garden. Purple color coded PVC pipes will take water from the cistern into the garden. At the garden site, we’ll use underground perforated PVC pipes deliver water to the garden by subsurface drip. This minimizes human water contact. The pipes will be sloped in order to use gravity to water the plants and avoid having to use a pump for that.
Frank -when dealing with grey water we know that it tends to have a high phosphorus count, an alkaline pH level which would fall in the range of 7.6 and greater, as you can see from the miniture section of the pH scale that we have up, and that it is high in sodium.The main contributing factor for these 3 issues would be laundry detergent, To be more specific its powdered laundry detergent.Many powdered detergents have a high concentration of phosphorus which would result in the discharged greywater being high in phosphorus content.-Greywater tends to have a high phosphorus concentration due to the detergents in the water. Over time this would contribute to the soil having a high phosphorus count as well. -The next issue we need to tackle is one of pH and alkalinity. Research has shown that even some of the best detergents for greywater use can be quite alkaline which, over time and with repeated application, can alter the soil pH considerably. Plant preferences for certain types of soil means that they are often starved of important nutrients or damaged by unwanted minerals when the pH is altered.-Salinity is mainly a problem with washing machine water as many powder detergents have a high salt content due to the use of fillers in laundry powders. using liquid detergents or choosing powders with no sodium content would be much safer for the plants.
Frank When planning our garden we first had to look at what type of soil we had. We did this by having it tested. Once tested we saw that we had a med to high concentration of phosphorus in the soil. We also saw that the pH level was neutral and that the grain size of the soil was classified as fine sand. -Now the effects/results of introducing greywater into this type of neutral soil is Alkaline soil. Which that leads us into our plants and our decision to use alkaline tolerant plants for our garden. We also chose to use native plants to florida which were perenial meaning that they would live for many years. Alkaline soil is Soil with a pH higher than 7.0, also called sweet soil, opposite of acid. ***The soils are neutral, with low nitrates but med-high phosphorous****
This is kind of a diagram overview of the garden layout**point out where things go**Scale
This is a 3D image of what the garden would look like from ground level.**But keep in mind that it will have more variations of flowers and shrubs it not just going to be what you see here**