Wastewater and You: Field Hygiene and Sanitation – Part Four, by LiquoredRabbit

Why should I care about Field Hygiene and Sanitation? – Part One, by LiquoredRabbit

“Wash Your Damn Hands”: Field Hygiene and Sanitation – Part Two, by LiquoredRabbit

The Never-Ending Problem of Human Waste: Field Hygiene and Sanitation – Part Three, by LiquoredRabbit

Fun Fact:

When using water for purposes other than human consumption, about 80% of that water will need to be disposed of properly.

Types of Wastewater.

Black Water:

This is any water that has human waste and is mostly contained within the latrines that were discussed in the last article.

Gray Water:

This wastewater comes from any other source except for the latrine. This can include handwash stations, showers, kitchens, or laundry stations. Disposing of this water can be relatively simple as it is not as hazardous as black water, just be mindful that there will be a lot more of this water. Gray water can be reused in a limited capacity as well which can help conserve resources.

Why does this matter?

Wastewater is still just that, waste. This water is dirty and can contaminate any source of clean water that it comes in contact with. Although the risks of black water might be obvious due to what it directly contains, gray water can cause its own host of problems that can put the health of a camp at risk. As stated earlier there will be a lot more gray water which can cause water pooling outside or near those facilities. Pools of water can attract unwanted insects and pests, as well as create an unclean area close to facilities that rely on cleanliness. For example, having water back up into your cooking area makes a much higher risk of food contamination. This water does need a place to go, and it does not have to be extremely extravagant, but it should not go into your latrine as it will lower its effectiveness by turning it into an unwanted pond.

What are some options?

Urinals:

Urinals are essential for keeping excess liquid out of the latrines and keeping them as efficient as possible. Although it is impossible to keep all fluid out of all the latrines these facilities help keep that fluid level as low as possible. This assists in the breakdown of the solid matter within those latrines. These facilities are also much easier to maintain and can be easily used by both males and females. All these facilities need to be placed like any other latrine. Those being, at least 300ft downwind and downhill from any food, at least 100ft from any ground-water source, and at least 100ft from any sleeping areas but within a reasonable distance for easy access and at least 3 feet above the water table (TB 593). Greywater can also be used in these facilities to help dilute urine. Just make sure no oil or grease from cooking or other sources are in this graywater as it will cause the soil to clog up and not allow the water to absorb as intended into the soil.

Soakage Pit:

This is a 4’x4’x4’ pit that is filled with aggregate material such as rocks or stones. Once within about 4in of filling the hole a 6 in border can be added along the top of the pit where pebbles or smaller stones are used to fill up the rest of the way to be roughly level or slightly lower than the ground. Most of the time you will not want to urinate on this structure directly but use it in conjunction with other urinal facilities to dispose of urine properly. This facility does provide females an advantage for relieving themselves as they would not have to worry about straddling over a hole like a latrine when trying to do their business. I would also advise after it has been used directly to pour a gallon or two of gray water over the pit to keep the flies away and the smell down. This facility can manage about 200 gallons of water per day depending on the soil type. That also makes this facility appropriate for basic gray water disposal as well while helping to dilute any urine as well. To make these facilities last longer you can add multiple pits to an area by keeping them roughly 20 feet from each other depending on how large each pit is. You also can dig them deeper as these pits rely on the walls of the pit to absorb the water and not the bottom directly. If it is noticed that the water seems to be pooling at the top that could mean that the soil is clogged and that the pit is full you will want to dig another pit away from this area and leave the other pit time to drain out. This is an extremely flexible option when discarding both urine and gray water and can be scaled up and down very easily to suit any camp’s needs.

Pipe Urinals:

This facility is basically a soakage pit that you stick pipes into to help the urine get deeper into the ground quicker. It is dug with the same dimensions and will include pipes over 1” in diameter and are approximately 36 inches long. The pipes will be inserted at least 8 inches into the pit and will have a basic funnel at the top. If you have any screen material around cover the funnels to prevent Anything from crawling down or falling into the funnel that may clog up the pipe. The addition of the pipes helps to use the soakage pit the most effectively by keeping the urine not directly on the top of the pit which can lead to unsanitary conditions as well as unpleasant smells. It is best to make sure that each pipe is flushed with some gray water and soap every day to keep them clean. Vents can also be added before filling the pit if you have the material and time to do so.

Trough Urinal:

This addition to the soakage pit is very advantageous when having more people as well as being able to have a more permanent facility. This is another simple facility where you would build a trough in a V or U shape that’s about 10 feet long. You can use sheet metal or wood but be mindful that if you are using wood, you should line it with tar paper to help so it does not absorb as much of the urine. You’ll then want to make sure that the trough is angled so that the fluid will flow into the soakage pit. This design is nice because you can add multiple troughs to a soakage pit and is quite easy to clean by just running soapy gray water through it daily.

Urinoil:

To this point, most of these designs have been very simple and quite easy to put in. This next option is much more technical in nature, but I felt it is worth being included as this option might be feasible in certain circumstances. It relies on the density differences between the oil and urine to create a seal so that there is no smell or ability for flies to reach it. This would be a modified 55-gallon drum that sits on top of a soakage pit and utilizes different diameter pipes and screens so as such when urine is added from the top it will sink through the waste oil to the bottom of the barrel where it will drain while using the oil to seal it in the barrel.

Grey Water:

As mentioned earlier there will be much more gray water that needs to be disposed of than blackwater. A soakage pit is an ideal way of disposing of this while also providing a second use for gray water, so you do not have to clean your latrines with valuable potable water. These other facilities are other options for when a soakage pit would not be appropriate due to a high-water table or poor soil type.

Soakage Trench:

This is another option if you have a shallow water table or difficult soil to dig through. This starts with a 2’ square pit at least 1 foot deep. From each of the sides, you’ll then want to dig trenches approximately 6 feet long and one foot wide. For each of these legs, you are going to want to gradually get deeper as you get farther away from your 2×2 pit. For example, start at around 1 foot of depth closest to the pit and taper down to about 1.5-2 feet deep towards the ends of the trenches. Fill in the entire dugout area with gravel stone or broken rock to facilitate drainage. This is designed this way to get the most amount of surface area for water to be reabsorbed back into the soil. Depending on the depth and how long the trenches are these facilities might fill up quicker than an average soakage pit. To mitigate this, you can add more of these pits and rotate their use to help stop them from filling up completely. This example below includes a grease trap that will be discussed later in this article.

Evaporation Beds:

Also known as evaporation fields, this is one of the simplest methods to dispose of grey water as it has a ton of capacity as well as sits on the surface. This option is used most often in hot and dry climates as well as areas where the soil is poor or there is a very high-water table. The downside to these beds is that they are primarily made for gray water only and are not meant to handle urine or any other Blackwater. These sites are usually quite large, in this example the bed is 8 feet by 10 feet. The outside border of the field consists of a perm that is approximately 12 inches high. Within the field, a series of rows of ridges are added which are about 6 inches in height. This allows for better water distribution within the field and acts as baffles when the water gets high. These evaporation beds can also be combined and tiered so that they flow into each other helping the evaporation process while also being able to dispose of massive amounts of gray water the downside of these facilities is that they require a lot of space and they needed to be monitored consistently to make sure that the berms are not failing.

Oils and Unwanted Grease:

It is also important to have an area for disposing of cooking grease and oils. You cannot add these products to any soakage pit as it will clog the soil and not allow proper absorption. Although not obviously hazardous, keeping oils and grease out of your wastewater disposal facilities helps to make sure that they continue to work properly. This can be accomplished by separating those materials while cooking in a separate container or using a proper grease trap that allows you to capture the grease for it to then be burned or buried with the regular garbage.

Barrel Filter Grease Trap:

This is what was displayed earlier in the article on top of the soakage trench. This is a 30 or 55-gallon drum that has the top removed and a perforated bottom. You then fill the drum with a series of materials. First, you put in about eight inches of small stones followed by about 15 inches of sand or wood ash depending on what you have. Finally, the barrel either has a screen material or you can use burlap attached to the top for larger solids. The sand and wood ash are used to help retain the material and will need to be replaced approximately every two days depending on how heavy it is used. That media can be buried or burned with other solid trash in the appropriate facility. If putting this on top of a pit you can remove the bottom entirely but when moving and cleaning it can become a hassle. The large downside of having to maintain this all the time is that you all need to have a decent supply of sand or wood ash to continually use this trap.

Wrapping up:

These facilities can take some time to put in so do not get overwhelmed, take your time, and keep things simple. These last couple of articles contain a lot of the big stuff, the really important stuff, and unfortunately, most of these options involve a lot of digging. When walking around your camp take note of areas that need drainage to prevent pools from forming these can be areas such as around hand washing stations or small laundry facilities that just might need a small soakage area to help mitigate standing water that would be accomplished with just a couple of inches of the soil replaced with an aggregate material such as small stones or pebbles it doesn’t need to be anything extravagant but just something that helps get that water back into the soil. Again, keep it simple.

Oh, and don’t forget to wash your damn hands.

Citations:

Headquarters, Dept. of the Army (2006, Sept.) Guidelines for Field Waste Management TB MED 593

Headquarters, Dept. of the Army (2014, April) Unit Field Sanitation Teams ATP 4-25.12

Headquarters, Dept. of the Army (2000) Preventive medicine services FM4-02.17