Water Filtration – How to Make Your Own DIY Water Filter
Water is one of the most important supplies to carry when out in nature. But without proper filtration, waterborne illnesses can make survival in the wild much more difficult.
Filtering your water is easy if you have the right supplies with you. To filter water, you need two food-grade buckets and a spigot.
1. Boiling
Boiling water is effective in addressing possible contamination from disease-causing germs and it is one of the most common household methods used for purifying drinking water. This method is simple, time-efficient and requires no special equipment to use.
However, boiling water doesn’t address toxins that are found in water such as microplastics, pesticides, manures, modern synthetic chemicals, drugs, heavy metals, neurotoxic microorganisms and radioactive substances. Boiling also doesn’t dissolve nitrates, which are commonly found in groundwater and can pose a health risk at high concentrations.
When water reaches its boiling point, it undergoes dramatic physical changes that can be observed on the surface of the water as bubbles begin to form. As the bubbles rise to to filter water the surface, the water is transformed into steam and vapour. Boiling water is an important skill to know when travelling in remote areas, as it helps to ensure travellers can access safe and clean drinking water. However, it is important to remember that a boiling method does not address the concerns associated with hardness of water and therefore should be used in conjunction with a filtration system.
2. Filtration
Filtration is a process of separating solids from a fluid. The fluid can be a liquid, a gas or a supercritical fluid. The solids particles are retained on the filter, while the fluid passes through. This process is similar to sieving, but a filter can have multiple layers instead of just one (see diagram below).
It is known that humans used simple filtration techniques to get clear water as far back as 6000 years ago. The oldest documented evidence comes from drawings and writings from Ancient Sanskrit and Greek, recommending various water treatment methods including filtration.
To make a basic homemade filter, all you need are two containers, a shirt or other cloth, sand and pebbles. Start by laying the fabric on top of the container. Next, layer rocks and pebbles, then sand. Over time, the oversize particles will be deposited on top of the sand, forming a cake layer that blocks the fluid phase from reaching the oversize particle region in the pore lattice (blinding). The filtered water will trickle through the oversize particle region and out the hole at the bottom of the container.
3. Filtration in a Bottle
A water bottle with a filter is a popular and portable method of making dirty water drinkable. It is also eco-friendly and cost effective compared to purchasing bottled water, especially in long-term use.
These bottles are often made of plastic and can be reused, which limits the amount of single-use plastic that is sent to landfills. Some are designed to filter non-potable drinking water, which is useful for people traveling to places where clean drinking water may be scarce.
The water filters inside these water bottles have a pore size of 1 micron and smaller, meaning they can keep out bacteria and parasites like Cryptosporidium. Unlike water disinfectant tablets or ultraviolet light wands, which only kill viruses and bacteria, water filters allow the water to pass through the material, but they catch the bigger impurities and contaminants.
To make your own bottle with a filter, start with a clear plastic bottle. Cut off the top of the bottle, then place a piece of gauze or cheesecloth over the opening. Secure it with a rubber band or piece of tape. Next, add the filter materials you want to experiment with. Make sure the materials are layered so that the smaller pore sizes can be trapped by the larger pieces of filter material.
4. Filtration in a Can
The water filtration system on the space station is complex and uses many layers to separate impurities. You can make a simple, DIY filter with items from around the house that will remove some of these impurities. Using an iterative design process, you will build and test multiple designs to see what materials work best.
Start with a clear plastic or glass bottle. Add cotton balls, charcoal, gravel, sand or other filter material in layers. Bigger filter materials catch bigger particles, while smaller filters capture smaller impurities and even bacteria. You may also want to include a layer of activated carbon in your filter, as this can improve the taste and color of your filtered water.
Once you have a filter that works, use it to clean a sample of dirty water. Observe how the water passes through the filter and into the to filter water factory bottom bucket. Note any contaminants that collect in the bottom of the bucket. You may notice black flecks in your filtered water, which is most likely charcoal from the filter. You can sterilize your filtered water by boiling it or placing it in direct sunlight.
5. Filtration in a Pit
If you find yourself without drinking water during a camping trip, you might be able to make some by filtering lake water with a stick of pine. Researchers have found that a simple filter created by peeling bark from a tree branch and then inserting it into plastic tubing can remove bacteria from contaminated water, reports NPR.
This type of filtration is called porous. Porous means that the pores in the material can trap large particles. The liquid that passes through the pore material is known as the filtrate. Typical filters include paper, cloth, cotton-wool, asbestos, slag- or glass-wool, unglazed earthenware and sand.
Scientists at MIT have discovered that the xylem tissue in a plant’s sapwood can also be used to filter water. A low-magnification fluorescence image shows E coli bacteria trapped primarily over pit membranes at the bottom of a tracheid, which is not unexpected as the xylem filter structure effectively amplifies its nominal tracheid area by a factor of 2a (D) L. SEM images also show that pigment particles 70 nm in size are rejected by the margo pit membranes, while larger ones pass through the tracheid walls.