Where there is no toilet (& sewage treatment options when there is one)

Human poo & pee causes more death, malnutrition and economic problems than any other single issue; yet like animal manure, can be a source of nutrients that can build health soils, regenerate landscapes.  This is the first of a few blogs where I'll explore consequences of terrible sanitation, better treatment options some of the radical new approaches to changing habit and practices that work, and some that really don't.

When there's no toilets in a community people "go" in the open, behind bushes, buildings, wherever they can find.  If you visit lots of villages you soon get that whiff of exposed poo, and if you spend a bit of time with that community you get to understand what happens when people are in such close and regular contact with their "wastes", from the high levels of diarrhoea and a host of other water borne diseases they live with (and pay for in money for medicines and visits to distant clinics).





It's clear: dirty, unsafe water is almost always a result of contamination from faeces and sewage.  And this continues to be one of the biggest causes for under-5 mortality, especially where there are no toilets.  This has to be fixed.

This UNICEF poster I saw last week on a wall in Sindh pretty much says
it all.  Surely it's not rocket science, and yet getting people to change
these habits and practices is one of the most challenging I have come across.

In Pakistan alone, it's estimated that around 93,000 people die per year from poor sanitation and related diseases - that's more than all the civilian deaths from earthquakes and floods in the country over the last decade.

I have seen this in countless villages and urban areas across Pakistan but also Liberia and other countries. Globally the numbers are staggering: some 2.5 billion people lack access to proper sanitation; 1 billion still defecate in the open - both of these are estimated to cause almost a million unnecessary deaths a year.

Emerging evidence is also proving that lack of sanitation could be one of the leading drivers of malnutrition globally.  This powerful story in the New York Times explains it better than most, explaining how constant infection in the gut prevents children from absorbing nutrients  - regardless of how much food or money they have access to. This causes chronic stunting whereby the body and the brain fail to reach their optimal potential, a process that can't be reversed; stunted children thus  can't function academically, economically on a par with their peers. The implications this has on Governments in poor countries is staggering: address water, sanitation and hygiene or half your people will be half as productive and smart as they could be.

This gets me thinking about recent trends from donors / banks to promote cash transfers (dubbed "social protection" or social safety nets).  Billions of dollars are spent this way, and there's strong evidence to support that it works in some settings.  But if water and sanitation aren't addressed in parallel... then these underlying drivers of vulnerability will just remain in place.

Other studies have looked at the economic costs of this shitty situation. In Pakistan it is estimated that poor sanitation costs the country some $5.7 billion annually in economic losses; while in India, which has the highest numbers of malnourished children in the world the losses are equal to a dizzying $54 billion - per year!

Thinking back to my time In Liberia, during the peak of conflict in 2003 (managing health agency MERLIN's emergency response), when half a million people fleeing the rebel attack poured over to "our" side of the city, as the country's biggest cholera epidemic in years was killing far more than the bullets and bombs.  We set up a lot of cholera treatment units, water tanks, toilets, and saved many lives, for sure, but had there been adequate treatment in place already, I'm starting to think it could have reduced so much mortality.  Note to self: find out how much of cholera-endemic Liberia remains without adequate sanitation and get writing to the Government!

But it's not just OD, it's also the scourge of untreated sewerage which seeps out of semi-urban and urban communities across Pakistan (and in so much of the world).  This stinky sludge ends up contaminating our fresh water sources, killing off other plant and fish life, creating weird natural imbalances like algae blooms which when they die give off some other toxic liquid waste which is also really harmful, potentially lethal to fish, birds and humans.

So all in all, human waste is equal to untold suffering, disease, pollution and contamination for people and other forms of life.  But - this is only the case if you don't treat it properly, if your systems for treatment isn't designed with full treatment in mind, or if it's only partially complete, which seems to be the case pretty much everywhere in the world I go.

Pit Latrines and treatment options

So... what are the options?  Well first, it helps to understand the basics of the biology at play. Let's take an example of a pit latrine, it will hold the liquid and solids together in an underwater state which means that oxygen can't get in, so it's anaerobic.  A multitude of harmful bacteria live in this state, which also produces loads of methane, and uric acid (from the pee) all of which smell bad.  So if you step into one of these pit latrines you will want to get out as soon as possible.  Really not ideal, but in an emergency, better than nothing when there are thousands of people living in a small area, and open defecation would be really dangerous for public health.

The alternative in this case is a compost toilet, which prevents the waste from becoming anaerobic by adding sawdust, straw, leaves or any dry thing (rich in carbon, crunched up cardboard will do). This absorbs a lot of the liquid and allows for little bits of air (thus oxygen) to get in and around the pile, which thus remains aerobic.  A completely different, thermophyllic process kicks in whereby in heats up, pretty much like a compost heap. These are unique "heat-loving" bacteria which exist in any composting process; over time they reduce these natural processes eliminate the harmful germs and bacteria: they "treat" our wastes, making it safe.  Moreover, it transforms it into a a really rich source of nutrients for plant growth.  One of the best books, brimming with resources to understand all this is the humanure handbook.

In other words: The problem and source of so much disease and suffering has the potential to be a great resource for regenerating a denuded garden, tree planting, and so much positive growth.


Pour flush toilets and sewage treatment    

The other types of toilets are the pour flush ones that most people living in cities or richer countries use every day.  Squat plate or sit-on-top they both hold a bit of water to receive your delivery, then water is added and it disappears, through a U-bend into a septic tank where it sits in that same anaerobic environment discussed above.  Millions of naturally occurring anaerobic tolerant bacteria in the tank consume the solids, changing it over time from solid to less dense and then floating scum, which then rise and leave the tank as more waste arrives.

Now, here's the gross and deeply unsettling part: septic tanks only partially treat this sewage.  It is still highly contaminated and is known to be one of the largest sources of ground-water contamination.  Bacteria, viruses, parasites (including worms and protozoans) are the types of pathogens in sewage waste and run-off from septic tanks.  The bacteria can cause numerous diseases including typhoid, dysentery, gastroenteritis, cholera; the viruses meanwhile include such infamous horrors as polio, hepatitis A, viral gastroenteritis.

Example 1: A latrine + septic tank built by a humanitarian organisation
in a village in Sindh, Pakistan following floods. Good intentions,
but potentially dire consequences as the overflowing septic tank has
created a perfect environment for dangerous bacteria and viruses. 

Here are a few examples... 

Example 2: raw sewerage running through a semi-urban
area of  Jacobabad, Pakistan.  These channels
are often blocked with garbage and overflow into the street.
Next stop: the nearest irrigation canal.

Example 3. Another overflowing latrine (Punjab)
another aid project, this time a good example
of the algae bloom, causing very hazardous
toxins.  Is this any better than open defecation?

I have hundreds of examples; the point is that a septic tank alone does not treat the sewerage waste.  Most designs recommend a soak-away pit. This is basically a hole in the ground filled with some gravel where the septic water seeps into, through a perforated pipe, or just straight into the gravelly hole.  And then, into the ground, maybe into the ground-water, we don't really know.  I've heard it said that soil acts as an excellent filter, but there's little research to show what happens when hundreds of households seep their waste-water into the same soil, it eventually builds up, and leads to contamination of ground water.

Built by IDEP in Bali, this constructed wetland is only about
18 months old and is seriously flourishing.
The water at the end of it smelled fresh.
The trees were growing at a phenomenal rate

So, treatment options for septic tank waste-water? I have found nothing better than constructed wetlands that allow plants to absorb the nutrients, to literally transform the harmful pathogens into plant growth.  There are quite a few different ways of doing this, which would (and do) fill entire books, but I have seen some excellent results here, by IDEP in Bali. See picture, left.

These are gravel-filled sealed tanks, into which water-tolerant plants are set. There is no soil, only gravel.  The roots transform the nutrients from the sewage waste (nitrogen, ammonia and urea) into plant growth.  The roots oxygenate the water.

Constructed wetland by IDEP, at
Ulluwatu in Bali. 

Ecological treatment of wastes can go up to large scale - as shown here.
 Thanks to Florence Cattin for this photo and for so much valuable advice on the theory and practice of waste water gardens. 

There are other wetland system too, like Jay and Clara Abrahams of biologic design, who build "wetland ecosystem treatment or WET systems".  These too are remarkable and I have visited many of their installations in England.  Jay points out these WET systems are not simple horizontal or vertical flow reedbeds; instead the WET systems use soil as the purification medium, not gravel as do conventional reedbed treatment systems.

A small portion of a WET system in the South of England, mid-winter.
from a quiet large institution, this treated
all sewage and grey-water wastes.  

During our visits Jay points out that the bacteria in sewage is relatively vulnerable when it leaves its septic tank and that if you have created a viable ecosystem in an un-lined wetland, studded with hundreds of grasses, bushes and trees, the proliferation of much stronger  bacteria devour these  "new kids on the block".

The waste flows from one pond to the other through the soil banks that separate each.  The extensive root networks and living soils provide a living filtration process.  Fish and ducks can be introduced.  Larger, older systems are like forests, attracting birds and enabling the return of biodiversity and health to the overall environment.  Moreover, these systems promote rapid growth of high value species which can earn the owner serious money. In this case willow is planted which is harvested and sold locally.

Lastly, there's biogas.  Human manure has less potential energy than that of cows, but it is still an organic material and will produce methane. It's such an obvious way to get energy from waste, but I doubt it would perform very well if the sewage weren't combined with other wastes, like sawdust and chopped up food waste, from kitchens or fruit markets.  We installed such a system in our home, described in this blog, but we haven't lived there enough since then to really learn from it.  But there is copious evidence already out there; we are well passed proof of concept.  Check this 2 minute video for one. Crucially, we now know that biogas digesters are very effective at treating harmful pathogens, though not completely, so care should be taken of the slurry emerging as a bi-product.  Again, not a problem if properly designed at the beginning.  

In Conclusion
It's clear that ecological systems can treat our sewage waste if we allow it to: the problem becomes an opportunity - and part of a solution for another problem.  We need to start making these links.

It need not cost much more than we are currently spending, if we adopt the right designs, for which we need more testing, experimentation and research.  Last week I joined a team from IDEP Bali who were teaching local NGOs in Pakistan how to build basic constructed wetlands - so we can start to learn from these results soon.