Circular wastewater and poo are hot! 

April 1, 2014 

No joke! Indeed, circular wastewater and poo are worldwide becoming more and more a popular topic. Indeed, last wednesday I was at an event in Amsterdam where the topic was water, pee, and poo turning into something valuable. And since I have also presented last weeks the outcomes of the 'Bioslurry: a supreme fertilizer' book, written together with Harrie Oppenoorth for Hivos, I thought it would be an excellent opportunity to write about this again, though from another angle than before. So what is that? Circular wastewater and poo? You will find out here.

Circular economy refers to organizing the economy and the product cycles in such a way that it is a closed loop in which everything is being efficiently used, reused, up-cycled and down-cycled. Therefore, this definitely has ties to products and services like wastewater and poo.

Wastewater is such a waste! What a waste to use at least 6 liters of water to flush your pee! And in most developed countries that is even drinkable water. Isn't that outrageous?! Then there is, next to the wastewater of showers and pee, the poo which goes into it. Poo is generally something we find disgusting, but not always. For instance, an adult is disgusted when s/he sees a child playing with poo, though the child finds it intriguing and funny. The conclusion by researchers is that we are becoming trained to disgust things (NRC Newspaper, 29 March 2014; Dekkers, 2014). So how can we turn poo into something more attractable? 

'Toilet flushing is the single highest use of water in the average home, so it also presents a prime opportunity for water conservation. With the average person flushing five times a day, toilets make up about 31% of overall household water consumption' (

Here comes the circular economy into place. How can that be? Well, when wastewater and pee and poo are treated by a machine, a (bio)digester or even algae and bacteria, it can be reused for biogas and the effluent as a fertilizer for crops. The fertilizer is often called the bioslurry (see publication for Hivos: 'Bioslurry: a supreme fertilizer'). The bioslurry can also be used as feed for algae, fish, and worms. And these can be used further for the processing of wastewater and poo, for consumption or for feed for pigs. The biogas can be used for cooking and lightning and when bigger installations are used, it can be used for electricity and mechanical power (see for more information on biogas and bioslurry this blog Bioslurry & Biogas).

Pee can also be processed and the phosphor can be captured and used for fertilizing crops, such as being done in the Heineken Music Hall in Amsterdam, The Netherlands. Indeed, phosphorous is an important component for crops, while we are running out of it. But when using pee, we can solve that problem. In addition, rainwater can be captured and filtered for drinking water, showers, and toilets.

All in all, when using these solutions, then we have a closed loop and a circular economy. It stays close to the source and home, but is within a closed circle. Isn't that great? So even wastewater and poo can become an attractable and hot topic!

So let's see what you can do to reuse your wastewater, pee and poo:

  1. Capture rainwater to filter and use it for showers and toilets.

  2. Shower shortly and flush efficiently. To reduce the amount of water being used by flushing the toilet, you can put a small bottle or brick into the water box of the toilet. This reduces the amount of water in the box.

  3. Try to see if you can construct a wastewater, pee and poo capturing system in your home such as a biodigester which you can use to generate your clean and green energy and use the poo as a fertilizer.

  4. Use all you have for such a biodigester, including kitchen garbage, an excellent feeding for a digester due to high amounts of potassium and nitrogen, which is good for crops.   







NRC. (March 29, 2014). He, bah! Article on what people are disgusted about, including poo. 

Dekkers, M. (2014). De kleine verlossing of the lust van ontlasten. 

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