WaterPod FBD Rainwater Purification
The WaterPod is a project based out of New York designed to be a sustainable, navigable living space, showcasing the critical importance of the environment and serves as a model for new living technologies. It is currently scheduled to launch in New York in May, 2009, navigate down the East River, explore the waters of New York Harbor, and stopping at each of the five boroughs it will dock at several Manhattan piers on the Hudson River. However, The WaterPod needed help developing several aspects of its design, including the processing of drinking water without outside help. To this end, The WaterPod contacted CSU Humboldt State University's Engineering 215 class. The Fire Breathing Dragons (FBD) are a group of students from Humboldt State University's Engineering 215 class who have developed a system for filtering rainwater based on the WaterPod's needs. The water needed to be drinkable after coming off the roofs and surfaces of the WaterPod project.
The FBD rainwater purification system exists to provide clean drinking water for the WaterPod Project. The WaterPod is designed to be a sustainable, navigable living space, showcasing the critical importance of the environment and serves as a model for new living technologies. The FBD rainwater purification system uses a sediment filter, an activated carbon filter, and a .5 micron ceramic filter, to help efficiently process water aboard the WaterPod. In addition it uses a First Flush system to remove a set amount of water at the beginning of a rainfall; water that would otherwise contain contaminats and sediment.
 Problem Statement
The objective of this project is to design a safe, cost effective, durable, easy to use water filtering system that will enable the Waterpod team to have a source of renewable, drinkable water supply.
The FBD Rainwater Purification Project was designed to attempt to meet a collection of criteria. These criteria were each assigned a number according to their importance, 10 being highest and one being lowest, as shown in the table below.
|Durability||The ability of the project to survive a set amount of time. The project should be able to survive the six months it is to be active. The materials and components should therefore be made of a strong, solid material.||8|
|Cost||The amount of money going into the project throughout the duration of its making. The total cost of the project will not cost more than $300. The project will not be constructed if any material components collectively exceed $300.||9|
|Safety||The project should not in any way threaten the safety of the WaterPod staff.||9|
|Functionality||The projects easy of use. The project should be easy to use on a daily basis. Since only crew members will be using it, the project does not have to be understandable to all ages.||9|
|Shipablility||The ability of the project to be shipped. The main components of the project should be able to be shipped to New York via a provided crate.||4|
|Educational Value||The ability of the project to be informative. The project should make some sort of effort to be educational to the general public. It should explain the mechanics of the project.||5|
|Water Quality||The effectiveness of the water’s treatment. Any water coming out of the project should be potable and ready to use on site.||9|
|Maintainability||The projects ability to be fixed when needed. The project should be able to be cleaned and fixed easily when the need arises||8|
|Aesthetics||How good the project looks. The project should not look out of place to a very high degree.||1|
 Description of Final Project
- 1) Debris Screen
- 2) Ball Valve
- 3) First Flush
- 4) Sediment Filter (25 micron)
- 5) Activated Carbon Filter (5 micron)
Our final design has two main steps. The first step is to divert the first 3 gallons of rainfall to the first flush to be diverted further into the river or for other unspecified use. The second step is to take the remaining rain and divert it to be filtered for consumption. (See Fig. 1)
The design is takes rain water that has already been caught and putting it through our final design to be filtered for consumption by the inhabitants of the WaterPod. Once the rain water has been caught and diverted to a single location, our final design can take effect. The rain water immediately goes through a 30o self cleaning debris screen. The debris screen mesh size is 1/16 inch wide. The self cleaning takes effect when the water hits the screen with debris the angle of the screen is great enough so that the force of the water pushes the debris down and eventually off the screen. (See Fig. 1, #1) The mesh screen keeps the big pieces of debris out of our design.
The first 3 gallons of rain water than flow straight down to the first flush. (See Fig. 1, #3) The first flush picks up the first 3 gallons of rain water because after it has not been raining for a couple weeks there is more contaminants on the catchment system, such as fecal matter, dust, bugs, and other sediment the air contains that could settle on the catchment. Inside the first flush there is a fiber glassed piece of foam float (about the shape of a small water bottle). The float floats to the top of the first flush reservoir where there is an O-ring at the top. The float has a rubber stopper on the top to prevent the first flush water from back flowing into the rest of the system. (See Fig. 1, #3) The first flush also has two ball valves, one on either side. The top ball valve is to shut off the first flush manually once it has filled up (See Fig. 1, #2) . This was put on there to be sure that no first flush water back flooded the rest of the system. The second ball valve at the bottom of the system is set up to hold the water in the first flush and then after the top ball valve is completely closed the bottom valve can be opened to release the first flush water, making it ready for the next rain fall. The first flush water can be discharged to the river or it can be used for other purposes but in no way for human consumption.
After the first flush is full or shut off the water than starts to flow through the filtration process. The system is designed to run off gravity fed pressure. The first two filtration processes happen right before the water enters the first tank (See Fig. 1, #4&5). The first filter process is a 25 micron sediment filter that gets any particle that is bigger than 25 microns out of the water to help deter the second filter from clogging (See Fig. 1, #4). The second filter is a 5 micron Carbon filter (See Fig. 1, #5) The carbon filter is before the first tank because the water is going to be sitting in the tank for an extended period of time, having the water go through the carbon filter will help prevent the stagnant water from growing algae or bacteria. The first tank is pressurized and will pump the water up to the 12 ft. water tower.
From the water tower, the water is once again gravity fed down to the final Ceramic .2 micron filter that filter the water immediately before it goes through the facet where is will be consumed as drinking water by the inhabitants of the barge. The Ceramic filter is the final filter that cleans the cysts, cryptosporidium, Giardia, and reduces turbidity, odor, and taste, out of the final consumable rain water.
|Item||# of Items||Cost ($)|
|3/4in x 10ft PVC||1||2.99|
|PVC Ball Valve||1||8.99|
The filters on this project should be changed out every six months at least, in order to maintain the quality of the filtered water, as well as avoiding clogging. In some cases the filters should be changed out sooner depending on how dirty the water being collected on a regular basis is. In the case of the WaterPod's rainwater runoff, the estimated time to replacement is still six months, but if used in a different location this replacement time may change.
- E6000 glue
- PVC Pipe Cutter
- 2 or 3 step PVC Pipe glue
- Pliers/Wrench (will vary in size for the desired size of pipe)
- Teflon Tape
 Discussion and Next steps
The FBD Rainwater Purification System has successfully met most of its criteria. Specifically durability, cost, safety, functionality, water quality, and maintainability. The projects filters can be changed out to different grades of filter quality, depending on the project's use. However, it is recommended that filters of at least the quality specified on this page be used if the water is going to be used for human consumption. In addition the size of the project can be changed by adjusting the length of pipe in between each section, making the FBD Rainwater Purification System versatile.
See Help:Footnotes for more.