STEMM REPORT

Biomimicry: Water Filtration System

Structure Filtration Design

 Introduction

Problem Addressing

The problem addressed is the lack of clean water in impoverished areas. This group is specifically targeting the Mupfure River (see Figure 1) located in Zimbabwe, Africa. Although the river is a main water source for many people, the body of water is also very polluted mainly with metal and mineral runoff from mining. 

 

Chosen Solution

The final design solution chosen includes two polypropylene plastic containers (see Figure 2). The smaller of the two containers houses the filtration materials. The larger of the two houses the filtration materials container (which also houses polluted water). The filtration materials container is where the polluted water is filtered into clean water using pebbles, sand, and activated charcoal. Other parts of the design include a rectangular supporting structure (made of PVC pipe) that holds up the filtration materials container and an area where the filtered water is stored. The polluted water first enters the system as the water is poured into the filtering materials container. This container has space at the top to store polluted water. The water then travels through pebbles, sand, and activated charcoal to remove harmful substances. The clean water then exits through small holes at the bottom of the filtration materials container.

The purified water is then stored and exits through a spout on the bottom of the outside container (see Figure 3 for exploded view of individual parts). The system also contains a lid on the top to fully enclose the system. Two grips are placed on either side of the outer container for handling purposes. Lastly, the container incorporates a Biomimicry aspect by imitating how ivy insulates. The product currently uses artificial ivy netting created. Ivy is proven to keep buildings warmer in the winter and cooler in the summer. By applying this aspect to the filtration container, the ivy will keep the purified water cool in the warm, African climate.

How Related to Systems Engineering

The product designed is an innovation because a number of water filtration methods exist today and this is just one of many. The product created is a closed system used for filtering pollutants out of water. The specific structural design is one component of the overall water filtration system.

  
Types of Engineering Involved

Different types of engineering is involved with the design of the water filtration system. A biochemical concept exists in the engineering of the materials to filter out harmful substances in the water. Industrial engineering is applied to increasing the quality and productivity of the overall system. Structural engineering is also applied to creating the interior structure of the water filtration system, which supports the filtration materials container. 

Types of Manufacturing Needed
 
Types of manufacturing needed for this water filtration system includes mass production. Although the user puts the system together by hand, each individual part of the system is mass produced (containers, spigot, filtration materials, PVC pipe). However, the craft system of individually creating parts is needed to make the layer of ivy around the outside container. 

Manufacturing Categories
 
The water filtration system falls under the food/beverage and industrial design categories.  The outcome of this product results in filtered water readily available for consumption for the users. Industrial design is incorporated because the system is aimed to increase the quality of water in a particular area.    

Science Concepts

The concept targeted is producing clean drinking water for a particular area in order to decrease the spread of diseases due to water contamination. Some examples related to the design solution include other filtration products such as the Lifestraw, Ceramic Water Filters, and Life Sack. 

The Lifestraw is a portable, cylindrical shaped tube that purifies water from pathogens. The device is

generally inexpensive and is very useful and has positively impacted third world countries (see Figure 4). Ceramic water filters are water purification devices that were first distributed to Cambodia and resulted in a fifty percent drop in illnesses back in 2002. The filters are constructed from fired clay, which create small pores that are small enough to remove most bacteria and protozoa. The

device relies on gravity and filters between one and three liters per hour (see Figure 5). The Life Sack acts as a container for shipping food as well as purifying water. Once the food is received, the sack can be used as a solar water purification kit. The contaminated water uses a solar water disinfection process with UV radiation and thermal treatment to kill microorganisms and bacteria. The Life Sack can also be worn as a backpack for easy transportation purposes (see Figure 6). 

The final design solution for the Biomimicry aspect includes a layer of ivy coating the exterior of the filtration container modeled after the ivy plant (see Figure 7). The theory is proven that ivy acts as an insulator and in fact, ivy keeps buildings warmer in the winter and cooler in the summer. This design is targeted to keep the water cooler than it normally would be in the warm, African climate as well as addressing the aesthetic features of the product. In addition, tropical species of ivy exist in Africa so having a product with an exterior resembling artificial ivy will not look foreign to the users.

 

 

 

 

 

 

 

 

 

 

 

Technology Involved

Plastics and materials play a significant role in designing both the filtration materials system and the support structure. Decisions had to be made on the type of materials and whether those materials would be successful in the role they are playing to either filter or support the

system. Particularly in the support structure, the topic of plastics was addressed in deciding what materials the container and support structure should be composed of. Polypropylene ended up being the plastic chosen for the overall container (see Figure 8) and the spigot, used to extract clean water from the system (see Figure 9). Polypropylene is durable, heat resistant, and is safe for food and beverage storage. The plastic is used for a wide range of products including packaging, textiles, plastic parts, and reusable containers.
Polypropylene is also resistant to a number of bases and acids so the plastic does not break down easily. In addition, PVC pipes (see Figure 10) and connectors (see Figure 11) are used in creating the rectangular supporting structure. PVC pipe is strong and sturdy and will do an effective job in supporting the filtration materials container. 

Mathematical Computations

Mathematical calculations were used to calculate the minimum amount of space needed to house the minimum amount of water in the cylindrical tank. The first step was researching the average number of people per household (figuring that each household would contain one water filtration system). The next step was determining the average amount of water a person drinks in a day. Those two numbers are multiplied together to calculate the minimum amount of water needed to be stored in the filtration system (see Figure 12).   

 

The next set of calculations involved determining how big the container needed to be to house that minimum amount of water. Estimates of the general measurements of the container were made to determine what the ideal size would be to ensure that the container sits sturdily and can easily be picked up to be moved around a home. The measurements were then altered to house the minimum amount of water needed. One key formula used was the volume for a cylinder. That resulted in cubic inches. A cubic inches to ounces online calculator was used to determine the number of ounces of that container. That amount was then converted into gallons (see Figure 13).

 

That same amount of height for the filtered water storage area is needed in the top reservoir to store the polluted water. So that height was doubled. The person with the filtration materials then shared the amount of space needed for those materials and that was added (see Figure 14).

 

Conclusion

In conclusion, different design, engineering, and manufacturing aspects are applied to this project. The water filtration project incorporates biochemical, industrial, and structural engineering. The project also incorporates mass production and the craft system for developing the system. The overall design of the water filtration system incorporates two polypropylene cylindrical containers. A smaller one, which contains the necessary filtration materials, rests on a rectangular supporting structure composed of one inch PVC pipe. Water is poured into the top, into the polluted water reservoir where the liquid rests until the polluted water is filtered through the pebbles, sand, and activated charcoal within the filtration materials container. The now clean and filtered water exits the filtration materials container through small holes in the bottom of that container and enters a clean water storage area. This is where the purified, drinkable water is stored until it exits through a spout for consumption.

            

  Significant technology in this product design includes mainly the abundance of materials used to construct the system, such as the polypropylene tanks, polypropylene spigot, PVC pipe, and filtering materials (pebbles, sand, activated charcoal). Science addressed in the product design incorporates aspects from other previous water filtration innovations and how those products filter water. Mathematical calculations were also used in determining the overall size of the container, which ended up being 25” in height and 14” in diameter. Once final construction is complete, the water filtration system will hopefully successfully filter out all harmful substances in order to produce clean, drinkable water.