How does solar distillation work?

The WaterPyramid is based on the principle of solar distillation which, over the years, has proven to be a highly efficient mechanism in cleaning water in order to provide safe drinking water. The mechanism behind solar distillation is simple and effective. Solar energy penetrates an airtight space through a transparent cover and is absorbed by the polluted water in the bottom of the space. The water (brackish, saline or contaminated with fluor and/or arsenic) is heated to temperatures up to 50-70 degrees Celsius, evaporates first and then condensates.

Within the airtight system, convection currents are formed between the cover and the water surface. Over the water surface, the air is saturated with water vapour, and it moves upwards where it is cooled by contact with the cover. Here, its vapour partially condenses and is extracted from the system.

WaterPyramidWaterPyramid and rainwater harvesting, does it work?

The total ground space of the WaterPyramid factory is used to collect rainwater during the rain season. After collection, the rain water is cleaned and filtered thoroughly in various stages. Then it is stored in a large tank were final purification takes place, using a simple silver disinfection method. The produced water is regular tested and reaches such an quality that it can be safely provided as drinking water for human consumption.

What is the quality of produced drinking water?

The WaterPyramid produces purified high quality drinking water. In the evaporation process, impurities such as salt, heavy materials and microbiological organisms are totally removed. The produced water is only brought to the marketplace for human consumption after that thorough testing of the microbiological and chemical parameters of the produced water meet the drinking water standards.

The table hereafter displays an example of measured conductivity EC and total dissolved solids (TdS) in the produced distillate and rain water in Mandinari, the Gambia.

Quality of various water sources in Mandinari, The Gambia

source

What is the life span of a WaterPyramid?

Although highly dependant on the specific climate conditions and the level of maintenance, generally speaking after three years of operations, the plastic foils have to be replacement for new ones.

Is pre-treatment of feedwater necessary?

Dependant on the quality of the feedwater, pre-treatment can be necessary. In that case we advise to use simple aeration and sedimentation, possibly in combination with Rapid Sand filtering techniques.

Is post-treatment of produced water necessary?

Yes, some treatment is necessary to remineralise the produced water. That can be achieved by passing the distillate over a calcium containing material of by adding salt tablets to the product water. If the produced water is being stored for longer periods, we advise dosing chlorine based chemicals to the system. Presently we are working on more appropriate ways to remineralise distilled water using locally available minerals.

What parameters influence the production rate?

The water production is related to local climatological conditions such as the intensity of the solar radiation, clouds, outside temperature, humidity and wind activity. Further, regular operations, cleaning of WaterPyramid surface, and maintenance will contribute to a stable water production.

WaterPyramidWhat is the maximum production of the WaterPyramid?

The water production is primarily related to the intensity of the solar radiation and the ground size of the WaterPyramid. In tropical regions, a water production of up to 2 liters a day per m WaterPyramid ground space can be achieved. Thus, a WaterPyramid with a ground space of 600 m produces daily a maximum of about 1.250 litres of distillate.

What can be done if we need more water?

The WaterPyramid is designed using a modular concept leaving space for (future) expansion on demand. WaterPyramids can be linked together to meet your specific water needs.

How environmental friendly is the WaterPyramid?

The electrical energy necessary to produce drinking water can be obtained using solar panels in combination with battery back-up system. Reverse osmosis (RO) desalinators in the same production range usually require about 10 times as much energy to produce 1000 litres of water. And compared to the RO systems, the WaterPyramid produces hardly any brine.

Are consumer based applications feasible?

Physical laws require relatively large sizes for the WaterPyramid (600 m minimum) to achieve competitive results. As a consequence, a reduction of size implies reduction of advantages, making the WaterPyramid less suitable for small scale domestic applications.

Why is UV disinfection better than chlorination?

Chlorination is often used to disinfect water because it is simple and easy. However chlorination is having the major disadvantage in that it releases for instance chloroform into the water. This substance is suspected to cause cancer. Our UV systems do not show this negative side effect.

Maintenance difficult?

Operating our systems is simple: the filters and the UV lamp can be replaced easily without technical assistance.

Water production range

Depending on the application, the water production ranges from 3.000 up to 17.500 litres/day.