Project: Eco Wash

We also tried also to find a solution for the water problem in Chazanga. This is one of the biggest problems Zambia has to deal with. Especially, the informal settlements still find great difficulties in tackling this problem. Most of the water supply comes from so-called waterpoints spread within these settlements. However, there are only very few for the amount of residents. Which leads to long queues, only little water per resident and a long journey picking up this water. Because of the shortage people use as little water for sanitation purposes as possible. This results in low hygiene standards and polluted groundwater.

With the fund given to us by Students 4 Sustainability we tried to tackle this problem. We made a design for a little sanitation buildings, which will improve the situation of the poor residents of these informal settlements. This building can be a huge value especially for the residents of Chazanga where groundwater can be found a problematic depth of 135m. During our stay we were able to design and build a prototype of this building, the Eco Wash. This is an improvement of the Eco San.

Eco San
PPHPZ is already trying to improve their situation by building Eco San toilet in collaboration with the residents. The Ecological Sanitation commonly abbreviated to Eco San is a dry toilet. This means the toilet itself does not use any water. The idea of the Eco San is that the faecal matter and urine are collected in three separated chambers. One chamber is for collecting the urine, and two chambers are for the faecal matter. However, only one chamber for the faecal matter will be in use at a time. When the first chamber is full after approximately one year, the second one will be used. In the meantime, a fermentation process will find place in the first chamber. After a while the faecal matter will be ready to be used as fertilizer for agricultural purposes. The urine will be diluted with water and can also be used as fertilizer. PPHPZ already constructed over a hundred of these toilets in the informal settlements. They are able to finance these toilets trough low-interest-loans given to potential users.

During our stay in Zambia we mainly focussed on the Multipurpose Centre. When we did the survey among the residents living close to the plot the most common problem was the water shortage. With that in mind we decided we wanted to help improving this situation. We came up with the idea of implementing a water harvesting system on the roofs of houses in these settlements. However, we also heard that washing is done outside their houses during the night, using the so-called bucket shower technique. That’s why we came up with the idea of developing a sanitation building, which harvests water from the roof, which can be used for washing and laundry, combined with an Eco San toilet. This way the building will only use very little water and can partly eliminated the water shortage.

AfbeeldingThe Eco Wash is a building that consists of two parts, the Eco San toilet and the washing part. The washing part can be divided into three components, the water harvest system, the bathroom and the sink for laundry and dish purposes. The combination with the Eco San toilet makes it a complete sanitation building, ideal for water-deficient regions. Now we will explain the new parts of the Eco Wash in detail.

Water Harvest System
Since the little water supply in the informal settlements, a water harvest system seems solution to improve this situation. The water harvest system collects rainwater from the roof. The roof measures 7,6 m2 and has a gutter which is connected to the water tank outside the building. The size of the tank can be adjusted to its number users, but for the prototype we just took the 500L tank. The tank is connected to two taps, one on the outside and one in the bathroom.

The bathroom of this little building situated next to the Eco San toilet. This bathroom is, just like the rest of the building, made out of concrete and Hydraform blocks. The concrete blocks are needed for the lower 1m to make the chambers of the Eco San toilet. This is the reason why the lowest four layers are made out of concrete blocks. Because the Hydraform blocks are made out of soil for 90% we thought this would give problem when the block get wet very often, they might start to crumble. That’s why we decided to finish the inner wall is with tiles to prevent the Hydraform blocks from getting wet. The bathroom measures an approximately 1,2 x 1,6 m, which seems small. However, locals considered this to be spacious bathroom. It has a tap inside which is connected with the water tank outside. The tap can fill another tank inside which is used for bucket showering. The floor is made out of concrete and has a drain. The water goes through this drain to the same storage as the urine. This way the two mingle, and no additional water will be needed to dilute the urine for agricultural purposes. This makes the little building even more environmental friendly.

On the outside of the building a sink with a tap will be placed. This tap is also connected to the water tank. The used water goes through the drain to the same storage where it mingles with the urine and bathing water. The sinks is meant for laundry purposes.

We are sure that the Eco Wash will be implemented in the informal settlements and in this way contribute to a solution for the water shortage. Due to all its advantages;
Only uses rainwater
The used water and urine is used as fertilizer
The faecal matter can be used as fertilizer
Improving hygiene
Less water carrying


Firstly, we discussed with PPHPZ about our findings in Chazanga, about the water problem and our idea to develop a water harvesting system. After some discussion we came up with the idea of making a little self-sufficient sanitation building. This building harvests rainwater, which will be used for washing. When this is combined with the Eco San we thought it would be a very complete and affordable building. We had a closer look at the Eco San toilets and after that we started to make a new design for the complete building using Revit, an architectural program. We made drawings of the prototype and discussed these drawing with the people of PPHPZ.

Cost and Materials
Together with PPHPZ we made a list of the needed building materials and estimated its cost. The list of building materials can be found in the appendix … It turned out that such sanitation building is very affordable. A contractor of the Eco San toilet wanted to help us with building this prototype. So, together with her and two builders we drove around in Lusaka to collect all the building materials. This took quite some time, because of the volume of the building materials and the limited space in the truck. However in one and a half day we were able to collect the most necessary building materials so we could start building.

First we had to decide together with PPHPZ where the building would be built. The best spot seemed to be next to the guardhouse. However, a few changes had to be made according to the contractor. So we made some adjustments on the design. After clearing the area of rubbish we started to mix the Quarry dust with cement for the foundation. This was quickly done and we poured the mix into the ditches. The mix needed to dry for a day to get strong, so decided to continue on Saturday, however the builders never show up. Also on Sunday it was a no-show of the builders, which was a setback and putted more pressure on our tight schedule. When we arrived on Monday the builders were already there, however they started over at different place. The reason was a neighbour who said that a water pipe was located underneath the foundations that will be replaced this year. This huge setback forced us to start building all over again at a different spot. Unfortunately, after a lot of discussion with Nelson, there was no other option than to put in on a place that was partly underneath a tree. We really did not like this location, since it will not demonstrate the water harvest system as good as on the first location. It also meant that our schedule became even tighter.

The first day instead of letting the foundation dry, we had to start building right away after putting the concrete in place. We were able to finish the different chambers and we had put most of the concrete blocks in place. We also placed the door of the bathroom.
The second day we continued with making the reinforced concrete surface that spans the two chambers of the Eco San toilet. We first had to make a wooden mold and cut the steel wire to the right length. After doing this, we had to use a pipe to make openings in the concrete surface.
The third and fourth day we constructed the Hydraform walls. This wall started from the level of the Eco San up towards the roof. This took quite a while, longer than we expected. The cornerstones needed to be shortened to the right sizes using a saw, this was labour-intense job. The doors were placed while constructing the walls. After placing the blocks, the corners had to be finished with mortar to make the wall more solid and stable.
The fifth day was mainly spend on the construction of the water harvesting system. We made the beams that carry the roof. Adjusted the corrugated sheets to the right sizes, connected the gutter to the roof and water tank. We placed the pipes, taps, sink, drains and build the storage for the used-water and urine. We put tiles inside and made a cover for the faecal matter chamber. It was more work than we thought on beforehand, however we managed to complete the Eco Wash just in time.

We also include two time schedules that show the time it would take to build the Multipurpose Centre and the Eco Wash.