Reaping healthy harvests from human waste

By Edwin Cheserek

Forget the stench and the fat flies that come from the pit latrine. Now the human waste is helping put health foods at your table.
Apart from providing plenty of food, the human waste is  now an agent of beauty.

If you doubt this, just ask pupils of Eldoret Educational Resource Centre in Uasin Gishu County.
They have learned how to use the human waste as raw material to generate a highly valuable fertiliser.

Higher yields
To get a rich harvest, many farmers around the world use artificial fertiliser.
But this is costly and to cut the expense, many use animal dung and droppings to improve soil fertility and hence achieve higher crop yields.

Now, through extensive research, human waste has been found to serve as a fertiliser substitute rich in nutrients that plants need to grow healthy.

Before tapping the waste for fertiliser, the school started to conserve the environment through ecological sanitation toilets (ecosan).

This, explains Jacob Katila, the school’s deputy head teacher, was a way of disposing human waste by avoiding polluting the soil through digging pit latrines in the school compound.

Katila says the institution came up with the idea of raising the foundation of the toilets in such a way that the urine and waste are separated.

Once the toilets are used and there is substantial content, ash is poured into the waste on the rear end where the waste is collected.

The ash adds nutrients and makes the waste odourless.

“There are two channels that separate the waste and the urine in that the waste goes to the harvesting gauge while the urine is channelled to the harvesting container,” he points out.

Organic manure
When the collection point is filled up, the waste is given time to decompose and another compartment opened for use.

It takes six months for the waste to decay before it is harvested and directly taken to the school farms and applied to crops as organic manure.

Mr Katila says those collecting the manure wear protective devices that are disinfected to kill bacteria that might be present.

The school founder, Joseph Patrick Kibet, says the institution is encouraging farmers to use this new type of fertiliser and avoid the inorganic one.

“We are teaching farmers the importance of this kind of fertiliser. We are even giving them samples to try out,” he says. 
Besides having a very short lifespan compared to organic manure, artificial fertiliser is expensive and pollutes the environment.

Organic manure from human waste enriches the soil for three to four years. Artificial manure is said to last about two months.
But if used in excess, the  fertiliser can scorch plants.

The school also uses waste from animals it keeps in the compound to generate biogas. The animals include goats, sheep, rabbits, cows and pigs.

Mr Kibet is optimistic that in the near future the institution would produce cooking gas from the same waste that is now using as fertilisers.

“We have already dug a collecting and digesting pit where the human gas will be directly pumped into various facilities for use,” he explains.

The procedure is similar to that of using animal waste to produce biogas.
The only difference is different waste materials.

At the school, the human wastewater — urine, water from bathrooms and kitchen as well as  other solid leftovers —  are channelled to a digester, a utility similar to a septic tank.

The mixture of the solid and wastewater accumulates in the digester for a period of time where pressure is created which in turn produces methane gas which is used for cooking and lighting.

The remaining solid waste and water will then flow to a bubble reactor where it undergoes natural purifications to produce clean water for irrigating farms.

This is the water they use for drip irrigation and so far the results are good.

In addition, the water is said to be rich in nitrogen and other essential nutrients that are required by plants.

The pupils learn about the various projects going on in what is called outside class learning. Human waste can be converted using simple technology to generate biogas as cooking fuel. Indeed, this is an effort to preserve the environment as it will reduce the number of trees cut down for wood.

Indeed, all you see is not as bad as it looks and next time you enjoy your fresh fruits and vegetables, remember it could have been grown by the best produced natural manures.

The Standard
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