Whenever I agree to terms for a new biodigester construction for a potential client, what I tell them is that we are not going to add the kitchen and bathroom waste water to that of the biodigester wastewater. Instead, a separate soakaway must be constructed for those two, and either they understand it or some of them are quick to disagree, saying that they do not want plenty of soakaways in their compound.
I also advise them that this is the best and safest option for them.
The truth is, even when you do consider the construction of a septic tank as your waste management option, you are still not going to add the kitchen and bathroom waste water to the septic tank; you will be required to add the kitchen waste water to a soakaway that will be attached to the septic tank.
I once built a biodigester for a family who had a four-bedroom house, and after two months of using the biodigester, I got a call that said that there was a lot of water in their backyard and that they were angry and disappointed in me for constructing a biodigester because it seems the digester is ineffective in managing their toilet wastewater.
After an inspection was done, they realized that the kitchen and wastewater had been added to the biodigester and its soakaway.
After enquiring from the family, they told me that when the plumber came to do the connection, he decided to add both the kitchen and bathroom waste water to the digester.
When you construct a biodigester, one of the first key things is to do a separate soakaway for your kitchen or bathroom wastewater. There is a reason for that: kitchen and bathroom water are not regulated, but wastewater from toilets is. Whenever you visit the washroom and you flush the unit, you cannot flush immediately after that. What it means is that, after the flushing of the unit, it will take some time for the water to fill the cistern again before it can be flushed again.
So let’s say you have a kid who goes to the washroom and then decides to stay there and play with the flush unit.
He or she is not going to be able to keep on flushing the unit over and over again because, after one flush, he will have to wait 2 or 3 minutes for the water to fill up again before he can flush; hopefully, at that moment, you will be able to find out what is going on and then you can put your kid in order.
But in the case of a bath tap or a sink, you cannot regulate it because if somebody goes there and mistakenly leaves the tap open, the water is not regulated, so all that water will just flow into the soakaway, which will render the soakaway ineffective.
That’s why we say kitchen and bathroom water are not regulated.
The main reason biodigesters work is that we separate the water from the human waste. If you add the wastewater from your kitchen or bathroom to the digester, you are basically making it unable to work to its full potential. This is why we recommend having a separate soakaway for your kitchen and bathroom water.
Because those waters are not regulated, if they are mistakenly left on, they will overflow the sink or the tank and then cause a whole lot of problems in your backyard.
What I do recommend, however, is that you put the water in the gutter or do an overflow tank that connects the pipes into the gutter so that there is a continuous flow of the water.
But if you do construct a biodigester, you know you are in safe hands because in the morning when you wake up, after visiting the toilet and flushing, it will take time for the water to fill the tank again before it can be flushed, so then that gives room for the biodigester itself to separate the water from the human waste for that water to go into the soakaway and still wait for the subsequent one that will come.
In summary, my recommendation to those who are interested in the construction of a biodigester is that a separate soakaway must be done for your kitchen and bathroom waste water. That way, you are going to have the peace of mind that you will need in terms of your toilet wastewater management.
And for biodigester builders, insist on having a separate soakaway done for the kitchen and wastewater. Sometimes prospective clients might complain that their cost will go up, but it’s better to have a safer option than to go back and do a digester, and then the wastewater from the kitchen and the bathhouse in the process will render the digester ineffective, and then people will complain and say the biodigesters do not work. Separate your kitchen wastewater from your digester soakaway.
