Know Your Septic Systems
According to the WHO / UNICEF, a meager 14% of the rural population in Cambodia has access to "improved sanitation." This includes flush wastewater toilets connected to sewer or septic systems, flush systems unconnected to sewer or septic, and simple latrines or pits unconnected. This means that 86% of the rural population has "no facility / field." That's right, most people use the ol' don't ask, don't tell policy and use the jungle as discretely as possible. So that's why everything is so green during the rainy season....
Well, considering their water sources are from pits dug in the ground to collect rainwater, it should surprise no one that there is so much disease and malnutrition in these rural villages. (Not to mention urban sanitation where a pultry 60% of the population has access to "improved sanitation"). That is why am researching septic systems. From what I've found, they aren't really difficult to make, and I'm considering the construction of some pilot projects in Cambodia.
While researching, I came upon a great, nay awesome, web site. It's called How Stuff Works. It has step by step instructions on everything from the Death Star to Botox. As a caveat, it took all my will power not to spend hours looking around. But it definitely has good info on septic systems for anyone considering a weekend project. Like they say, don't shit where you eat. Really, it's important.
~ J-Dub
posted by Cali Thais at
3:44 AM
4 Comments:
Gee, john, i offered my septic expertise to you a long time ago, and I could tell you more. I still do a little bit of the sewer design action. A properly designed septic system will last a good 30 years. All they are is a tank that feeds a drainfield via gravity which is a long trench in the ground with a pipe covered in gravel. Knowledge of the soil is the key to a system that will last a long time, will properly treat the wastewater, and will be relatively maintanence free. Remember not to put your drainfield near streams or underground water storage. Also, septic tanks need to be pumped every 3 years or so. Otherwise, solids will make their way to the drainfield and ultimatly destroy it.
Because they harvest rainwater, another nice invention which has been around for thousands of years is a rainwater cistern. What it is is a concrete tank, often underground, which collects rainwater off of a roof, or an impermeable substance suspended off the ground to act as a collection system. Because the water is taken from the relatively clean roof and stored underground in a concrete tank, the water remains relatively pollution free. The use of a pump and a charcoal or sand filter can further treat water before it is ingested. Pumps don't have to be powered by electricity. A handpump would be adequate to pump a decent amout of water through a filter for drinking and cleaning.
Perhaps a google search for the group "Water for People" might reveal what other organizations are doing to solve the clean water problem. No point in reinventing the wheel.
I was going to post a comment making fun of Johnny D's vast experience with toilets and the poo-poo found within ... but he basicaly did it for me.
Thanks for the offer Johnny D. Your vast knowledge of poo does not go unnoticed. I remember back in June I had such little knowledge of Cambodia that I didn't know how to respond.
Like anywhere, the soil varies quite a bit from area to area in Cambodia. In the rural villages where we have the most experience, the soil is quite hard when dry, but as soon as it is subjected to water, it is like mud and water easily percilates. The water table is pretty deep and water is usually plentiful throughout the year if a village has a well.
The rainwater cistern invention sounds like a good idea for places where water is not accessable.
But the problem is during the wet season when farmers flood their rice fields with water. We're talking water and rice everywhere. I can't imagine a drainfield would be a good thing to have around. Isn't this a problem? (But then again, right now their waste goes into the fields anyway). I mean, if you dig a three meter hole in the ground it will fill up with water within 2 hours during the rainy season. If you put a sub-pump in the bottom and pump out the water in the hole all night, the next day, it will still have water in it. That's how much water is in the soil during the wet season. What do you do with waste when the soil is like sand and it floods regularly?
"Water for People" looks solid at first look. I'll look into them more.
Keep you poop real.
I was going to write a comment about Shark's vast experience with salt and poo poo sex, but he basically did that for me.
The soil on the surface is not really the critical factor in designing your leaching trenches, its the soil within the first two meters or so in that you are really interested in. The soil typically varies pretty dramatically everywhere, as Shark can attest, and recommendations must be made on a site by site basis. Remember in the ground and everywehre in life, shit flows downhill. When determining the location of your septic system, don't put it downhill from a major source of irrigation.
I understand that there is a lot of water in the rainy season. I think the problem is keeping potable water separated from your sources of contamination. This is where the cistern comes in. By immediately isolating rainwater from source that is known to be safe, such as a roof or a large plastic tarp suspended from the ground, then you are minimizing the points in which your water can become contaminated.
You can pump all the groundwater you want out of a hole in the ground, just make sure that this water doesn't make it into peoples' mouths. It is importatant to separate your irrigation water from your rainwater. It might be beneficial to create irrigation systems in which groundwater is captured and pumped into a water tower, or a small reservoir where it can be used to irrigate crops when needed. Meanwhile, rainwater is also being harvested from safe locations and is treated for potable uses, such as drinking or cooking. Such systems would probably be fairly easy to set up and maintain.
To summarize, it appears as if three seperate systems should be established in order to reduce disease.
1. A system of capturing and storing and treating clean potable water. Even rainwater should be treated.
2. A system for capturing and storing water for irrigation.
3. A system for disposing of waste beneath the ground in locations where it won't be hazardous to your rainwater.
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