11 Facts You Need To Know About Bio Digester Toilets

Biodigester toilets are biodegradable systems that turn human solid waste into organic manure for safe disposal in the environment.

These toilet waste digesters address the liquid and solid wastewater treatment issues at residential, commercial, community, and public facilities. This is in sharp contrast to septic tanks, cesspit tanks, and manholes that require periodic emptying.

Before explaining how this is done, it’s worth noting that the kind of biodigesters here are NOT those that produce gas that has come up lately.

The septic system is a large holding tank designed to store human waste materials, which must be periodically removed by pumping.

We have answered the most frequently asked questions by our prospective customers here.

1. History of Biodigester Toilets in Ghana

The history of biodigesters in Ghana is not clear, but they became prominent after the 2014 severe cholera outbreak in some parts of Accra.

The government and the World Bank then decided that, considering the sanitation situation, especially in low-income households here in Accra, bio-digester toilets were our best bet.

The Government through the GAMA Project, has since been implementing this policy through the installation of low-cost bio-digester toilets. In fact, using biodigesters as an integrated toilet wastewater management system is nothing new.

In some parts of New Zealand, the Samoa Islands, and Papua New Guinea, these eco-friendly biodigesters are used effectively to solve toilet waste water treatment issues. This technology has proven to be a better option than traditional, foul-smelling septic tanks in Ghana.

2. How do bio digesters work?

Bio digesters eliminate toilet waste water odors by overpowering the naturally occurring bacteria mostly found in septic tanks and manholes.

For example in biofil digesters, the wastewater from the flush unit (water closets) is organically filtered through a porous slab, allowed to penetrate a small rock-filled soak hole from which it leaches into the soil.

In places where there are gutters, the black water is organically filtered out of the bottom of the digester and drained into it.

Bio-degradable toilet waste digesters have established themselves as the modern-day answer to KVIPS, pit latrines, and septic tanks as toilet treatment systems in Ghana.

3. Where does the wastewater from a bio-digester go?

There are a lot of misconceptions about biodigesters as an effective toilet wastewater management system.

One of the most asked questions is where the flushed water from a water closet goes.

Usually, people are not sure how such a small box can contain all this water and serve a whole household without getting full.

However because bio-digester toilets are used as part of the process of treating bio-degradable toilet wastewater and sewage sludge, the process often referred to as anaerobic digestion is adopted.

Natural composting organic manure is introduced to treat all organic biodegradable materials through the natural process of anaerobic decomposition.

Flushed water and solid waste enter at the top of the biodigester where immediate separation of solids and liquid contents of the waste occurs. All liquids will then be organically filtered out of the bottom of the digester and drained into the soil where further and final decomposition occurs.

Other solids (toilet rolls & all degradable cleaning materials) are decomposed and converted into rich & safe soil for easy disposal.

Now the final effluent (wastewater) produced is a clear odorless liquid suitable for discharge either into a waste watercourse, through a customized soak hole trenches, or a drain-filled system.

4. Waste Water Soak Hole Construction

We fill the bottom of the soak hole with a layer of rocks. With each rock about 3” in diameter.

For the layer of large rocks, we determine how many inches high they should be based on the depth of the soak hole. A typical construction of a soak hole must ensure that the bottom of the soak hole is 2’6” below the bottom of the leachate pipe hole.

The depth of the soak hole from the surface of the ground will depend on the water table for the toilet site. Regardless of how deep the digester bed hole is, we maintain the bottom of the soak hole at the above-given specifications.

5. What Becomes Of The Solid Waste In A Bio Digester?

Because the biodigester is a simple compact onsite organic waste treatment system it essentially uses a biological filter consisting of a fiber, a medium of black soil, and in some cases porous concrete. The bacteria and other organisms generated through this technology then bio-degrade solid waste.

So for the layperson, the immediate question that comes into mind is “What becomes of the human remains in a biodigester and what does it look like”?

When the digesters get the maximum per day uses, it will take at least 5 years and as much as 15 years in some cases for the toilet waste box to get filled up and ready for dislodging which involves scooping out the human remains (manure) with a shovel for easy disposal.

The solids waste and human waste remains are harvested as pure compost which can be used for agricultural purposes after years of usage. The harvesting time depends on the number of users in a given facility and the type of soil on which the biodigester was installed.

This is totally new to what we have been accustomed to over the years whereby a tanker shows up to collect solid waste which often finds its way into the sea.

In highly developed countries, the process is used for industrial or domestic purposes to manage waste and reduce the emission of landfill gas into the atmosphere.

6. Reasons why people choose biodigester toilets in Ghana

Even though biodigester toilets cost have come up lately for public discussions, there’s no doubt they have become the choice for most homeowners in Ghana today.

While there is no concrete research available that shows the exact percentage currently adopting this wastewater treatment method, there is no doubt that they are effectively helping to improve the sanitation situation in most homes.

7. Biodigesters cost less to install

They are cheaper to install (as compared to digging a manhole or buying culverts for septic sewage tanks). Even the idea of digging all those feet and doing all those concrete works makes bio digesters your best bet any day.

8. Eco-friendly technology

Biodigesters are the most environmentally safe and highly improved means of treating toilet wastewater in Ghana today. The use of locally sourced materials means that they are safe for the environment. They are easy to maintain and do not come at any additional cost to the homeowner.

9. No more dislodging

There have been some misconceptions about this saying. But what we are simply saying is that with DreamHouse biodigesters, you don’t need a typical truck to show up saying they are there to empty your tank.

Because digesters use an aerobic digestion process, solid waste after a cycle (which usually lasts between 5 to 8 years) changes into sand (manure) which can easily be disposed of at your backyard. As a result, no septic sludge is stored and as a result, the biodigester product has a unique ‘odour-free’ operation guarantee.

10. Groundwater not affected

Water is directed into top soils where microbial activities are most active. Nutrients are removed by soil bacteria decomposition. Digesters are designed above ground and typically have no more than a week of decomposed contents in them.

11. Internationally approved

Not only do biodigester toilets in Ghana have governmental approval (you can check from the nearest District Assembly), but they have also received worldwide acceptance by the World Bank.

In fact, over the last 5 years, the Government of Ghana has received over $150 million in grant from the World Bank as part of a project complementing efforts to provide low-income households with increased access to improved sanitation and water supply. Simply put our biodigesters are safe for everyone; private homes, offices, and public needs.