Biodigester in Kenya Quickly Replacing Septic Tanks- Expert View
Biodigester System + Material Cost Breakdown.
Biodigester is a decomposition toilet system which decomposes human excretory solid waste in the toilet digester tank using specific high graded bacteria. These waste are converted into methane gas and water of which water can be discharged to the desired surface. The biodigester system consists of an inlet that collects black water waste from toilet into the septic tank and an outlet that takes away displaced water to the soak pit.
How Does Biodigester Work
Biodigesters are designed to be incubators to bacteria and to provide all the conditions necessary for aerobic and anaerobic decomposition of organic waste. Enzymes are put into the tank to catalyze the process. Once installed properly, they function very well and exhausting is completely eliminated.
Human waste is largely organic. This can be degraded by bacteria thus reducing the mass of the waste. The water can then be recycled. Biodigesters treat black water. The grey water that leaves the bathrooms, sinks and hand wash basins bypasses the biodigester and can be directed to the soak pit. However, solids, soaps, oils and fats must be removed from this water before recycling. The end product is re-usable products such as water, which can be re-used for flushing toilets and farming after the water treatment.
The system does not need to be emptied regularly because the waste that comes out of the ‘Bio-digester’ has been treated so much so that it can be released into the local environment. The system works by storing the untreated waste- allowing the solid waste to fall to the bottom of the tank. Air is then used to agitate the sludge so that aerobic digestion can occur.
Biodigester in Kenya quickly replacing septic tanks
Waste management has been one of the major problems to many Kenyans especially for those who live or are putting up homes in urban areas that are not served by proper sewerage facilities. The cost of building and maintaining septic tank is high but thanks to the new waste management solutions ; Biodigester. The system is fast becoming a go-for waste water management and has been used in well-established waste water treatment firms, water and sewage companies, several municipalities, schools, slaughter houses and commercial and residential estates. Many have testified on how the process has helped them manage their waste. Below are some key advantages of biodigester
Advantages of biodigester
Here are some of the advantages of biodigester as an on-site sanitation system.
Biodigester Cost Cheaper to install that Septic
The biodigester tank is actually cheaper to install than the cost of constructing a traditional septic tank. On the site, one needs to excavate a hole that is 1.1 meters deep and some trenches. The inspection chambers or manholes required are also few.
The system occupies much less space and can be used where space is an issue.
Traditional septic tanks require a much deeper hole and that comes with high costs of excavation. Excavation is also very tricky and expensive in areas that have a lot of rocks, swampy areas or areas with high water tables as well as areas that have very loose soil.
Little or no maintenance-Requires no Exhausting
Exhausting a septic tank is the process of draining it when it is full. This process is undertaken after a number of years depending on the size of the septic tank.This an added expense, not to mention how messy and potentially hazardous it can be.
Unlike traditional septic tanks, the biodigester does not need exhausting. This alone makes the biodigester the best option for dealing with sewer.
This on-site sewer system does not emit any smell whatsoever.
Septic tanks emit a lot of bad smell because gases are released into the atmosphere. Imagine having to live with a foul smell which gets worse with every passing year?
Safe on the Environment
The biodigester enhances the environment in many ways:-
- The water that is produced is usually soaked back into the ground and therefore increases the amount of water found underground.
- The same water, which is rich in nitrogen and other nutrients can also be used for irrigation or watering gardens. This enhances the fertility of the soil.
Solid Structure and Design
The system is built out of reinforced concrete that is already enzymed, giving it structural strength that is superior to any other material such as cement, plastic, brick or mortar.
Easily withstands pressure and stress making it extremely reliable. The tank is small and cylindrical and thus, able to withstand pressure from the soil. This cylindrical design with a continuous wall ensures that stress is uniformly distributed, unlike rectangular designs where pressure is exerted on corners and joints.
The on-site sewer system comes with a 3 year post installation warranty from the installer which covers defects. But it can be used for more than 30years.
Approved by NEMA
The biodigester has been fully approved and recommended by NEMA (National Environmental Management Authority) .
The biodigester has been in use in Kenya for over 17 years without any major issues.
Different sizes of The Biodigester Tanks
There are 3 different types of biodigester septic tanks available, based on size.
- The Standard Biodigester – This is the smallest size and it can handle between 1-30 people (continuous users). This is the best size for residential properties and small commercial establishments.
- Medium Biodigester – The medium size biodigester can easily handle 30-120 people (continuous users) and is therefore ideal for mid-size establishments, apartment blocks, hotels, farms and small gated communities.
- Large Biodigester – This is the biggest size available for 120 continuous users or more. This is great for much bigger establishments, estates, shopping malls, hotels, schools, hospitals and blocks of flats.
Apart from these 3, Custom designs can also be created for different clients.
The biodigester offers the best solution for residential and commercial on-site sanitation system.
Biodigester Cost in Kenya
The cost of setting up a biodigester in Kenya varies greatly depending on the size of the biodigester and whether it is for a residential home or commercial building. The standard biodigester can cost from Ksh 70,000 (Download Material Breakdown below) for residential home to over Ksh 300,000 for commercial buildings and apartments but will depend on the total number of users of the biodigester.
The price is subject to changes depending on the site location, the type of soil on the site among other things. The basic materials (plus cost) needed are indicated in the Cost Breadkdown Below.