Muddy Waters
Overview
Civil engineering is a profession which encompasses a great many sub disciplines, including water resources. A population is dependent on its water resources for drinking, bathing, irrigation, agriculture, etc. Being that water is often acquired from uncontrolled, unclean sources, it is necessary to remove impurities to ensure the water is safe to use.
Eligibility
There shall be no more than three (3) members allowed on each team. Both undergraduate and graduate students are allowed to participate, however, only 1 graduate student is allowed per team.
Objective
Each team will pre-construct a homemade water filter system inside of a two-liter bottle. Items that function solely to treat or purify water will not be allowed in the competition. This includes, but is not limited to: reverse osmosis systems, water filters, and water purifiers. In addition, charcoal filters, such as those found in coffeemakers are not allowed in the competition. Each filter will then be tested with a “city sewage” mixture:
- 1:4 soil to liquid mix
- Soil will be comprised of:
- 80 to 90% passing the No. 4 sieve
- 20 to 30% passing the No. 200 sieve
- Up to 15% organics
- Part of liquid will also be comprised of vegetable oil
Rules and Restrictions
- Each team shall construct their filter system using a single two-liter bottle as the containing structure. No valves or other devices may be used to control water flow, or the team member in the treatment area may manipulate the equipment to pass water through the system.
- Each team shall have a system inlet and outlet.
- Inlet: There is no limit to how far down from the top it can be cut. Funnels will not be allowed.
- Outlet: Each team shall drill 5 holes in the bottle as a system outlet. The diameter of the outlet holes must be ¼” ± 0” in diameter.
- Filter systems may have an unlimited number of components. However, two of the layers must consist of granular material and a strainer. Additionally, the total cost of the filter system must remain below $200.
- The singular piece of filter must have a diameter no greater than 6.5” and have an apparent opening size of No. 8 or smaller. There is no limit to the thickness of the filter.
- 250 grams of each granular material in clearly labeled, transparent container must be provided. A sample of the strainer of a size approximately 6”x6”, or of a diameter approximately 6.5”, must also be provided. Labels must be attached to both samples with the university name. If samples are not provided, the team will be disqualified.
- Each team will produce a short report (limited to 5 pages, including the title) on their filter. This report should include:
- Title page with the university and team member names (this counts as one page),
- A diagram of the filter with all layers coherently labeled,
- A list of all materials used,
- A sieve analysis gradation chart or table of granular material used in the filter,
- Description of design process,
- Cost breakdown of the filter system,
- An appendix with a material data sheet for every material used and purchasing receipts, including the filter mesh, if available. If a data sheet is not available, include the universal product code instead. The appendix does not count towards total number of pages.
- You may submit the report as a hard copy in-person on the day of the event, or submit earlier online with a PDF. If you choose to submit online, please email [email protected] with the subject line: “University Name – Muddy Waters” (updated 2/7/2023)
- Each team should be prepared to give a short (up to 5-minute presentation) to the judges on the engineering design behind their filter systems.
- Read all FAQ questions and responses. Responses to any question should be considered binding rules, and failure to follow them will result in disqualification.
Testing Procedure
- Each filter will be rinsed thoroughly with distilled water to ensure each filter has the same level of saturation (approximately 100% saturated).
- Each team will receive 0.5 liters of the pre-made soil-water mixture (the influent sample).
- The sample will then poured by one member of the team into the system inlet and through their filter. Upon pouring this sample in, the supervising judge will start a stopwatch. The sample may only pass through the filter system once during testing.
- The stopwatch will be stopped when 0.4 liters of effluent sample have successfully passed through the filter, which is determined by having the water draining into a beaker with 0.4 liters marked. If 0.4 liters of effluent sample is not collected within 15 minutes, the team will be deducted a percentage of the 30 points based on the sample collected. For example, if only 0.2 liters (or half of the required sample) of effluent sample was collected in the 15-minute time frame of testing, then the team will be deducted 50% of 30 points, or 15 points.
- When either 0.4 Liters of the effluent sample is collected and the timer has stopped or the 15-minute testing timeframe is completed, the collection beaker will be taken to be tested by a supervising judge.
Scoring and Judging
Points will be determined from the following listen of items. The maximum score of points a team may receive is 100 points.
|
Amount of time to produce 0.4 L of the effluent sample* |
40 points |
|
Turbidity |
40 points |
|
Technical Report and Presentation |
20 points |
|
Total |
100 points |
* If 0.4 liters of effluent sample is not collected within 15 minutes, the team will be deducted a percentage of the 30 points based on the sample collected. For example, if only 0.2 liters (or half of the required sample) of effluent sample was collected in the 15-minute time frame of testing, then the team will be deducted 50% of 30 points, or 15 points.
The final score will be based on the sum of a team’s rankings in the three categories, with the lowest cumulative score receiving 1st place.
Teams will be disqualified from ranking for soda bottle filters that violate the rules of construction, have materials that are not visible through the soda bottle walls, and ‘leak’ water or granular media during competitive filtration.
Comments (20)
Starr Alfonso
October 15, 2022 at 10:49 pmThere’s a missing 10% in calculating the score, is it on a out of 90?
nbohaczyk
October 17, 2022 at 2:01 pmPlease see the updated Scoring Chart for point distribution. It will total to 100 points max.
Emily Rodriguez
December 8, 2022 at 3:23 pmCan active carbon be used and its other derivates?
nbohaczyk
December 13, 2022 at 7:13 pmYes, the filter system may have an unlimited number of components, as long as total cost of system is less than $200.
Maya
December 14, 2022 at 8:50 pmIs there a minimum or maximum of one straining component? and what defines the strainer?
nbohaczyk
December 16, 2022 at 1:32 pmYou may use as many components in the filter system as you’d like, as long as the total cost of the filter system is within the $200 maximum budget. A strainer typically consists of a fine-mesh or filter paper, but may be any media that would meet the definition of a “strainer” (a device having holes punched in it or made of crossed wires for separating solid matter from a liquid.)
Robert
January 30, 2023 at 4:01 pmWhere will the water for the mixture be sourced from? Will it be lake water? Tap water?
nbohaczyk
February 1, 2023 at 1:11 pmTap water mixed with contaminants. There is a general mix of liquid:solids under the competition page.
Arya Desai
February 3, 2023 at 5:32 pmWill we be submitting a hard copy of the report at the conference, or will we submit a pdf online before the competition?
nbohaczyk
February 7, 2023 at 3:30 pmYou may submit a hard copy or a PDF online before the competition, both will be accepted. Methods to submit online will be updated in the rules.
Bryant Morales
February 4, 2023 at 7:00 pmWhat if the components for the filter are donated. Does that still count towards the budget?
nbohaczyk
February 7, 2023 at 3:28 pmNo, donated items will not count towards your budget. Just please make note of them in your report.
Bryant Morales
March 2, 2023 at 9:36 pmDoes No. 8 or smaller means we can use a piece of filter with smaller holes than a No. 8, or a smaller number like No. 4 and No. 2?
nbohaczyk
March 3, 2023 at 9:15 pmNo. 8 or smaller is related to apparent opening sizes (AOS). You may use a material with an AOS of 2.36 mm or smaller.
Starr Alfonso
March 2, 2023 at 10:15 pmFor the 1:4 soil to liquid mix: Is there a specification of organic?
nbohaczyk
March 3, 2023 at 9:12 pmUp to 15% of the soil mix will be comprised of organic materials.
Starr Alfonso
March 2, 2023 at 10:36 pmFor the 1:4 soil to liquid mix: Is there a specific vegetable oil?
nbohaczyk
March 3, 2023 at 9:12 pmVegetable oil will comprise a small percentage of the liquid ratio.
Rose Cyr
March 21, 2023 at 10:35 pmAre we allowed to use more than one piece of mesh to keep materials from flowing to the top of the filter?
nbohaczyk
March 22, 2023 at 10:09 pmNo