WaterPurifier

A WaterPurifier being used

The WaterPurifier is a water treatment system that can be installed in rural areas. The unit removes all pathogens and produces clean and safe drinking water without external use of electricity or chemicals.

The contaminated water is first filtrated with a ceramic filter, then a second time using a disinfection unit which is solar powered. The applied membrane is a 1 m2 tubular ceramic ultrafiltration membrane with a pore size of 40 nm. The ceramic membrane has 120 tubular membranes inside with inside diameter of 2 mm. With the application of electrolysis, the produced water remains free of bacteria and recontamination cannot take place, because of the production of chlorine residue.

The WaterPurifier is different from other water purification systems because, it only needs sunlight to operate and the unit creates disinfectant that provides residual chlorine, thus preventing recontamination. It can be used everywhere. It is extremely robust, compact, and easy to transport. It helps organizations in developing countries.

Advantages	Disadvantages/limitations
- Good quality of water. - Easy to operate - It uses solar energy. - Quality control of the purified water with an indicator stick - Environmentally friendly - Operates on solar energy - It filters the water with a ceramic filter that lasts for approx. 5 years. Thus no need of disposable filters. - Chlorine residue preventing from recontamination from bacteria	- Spare parts only available on order

Suitable conditions

The WaterPurifier is not designed to remove turbidity or chemical contaminants.

Highly effective for: Somewhat effective for: Not effective for: - Bacteria - Viruses - Protozoa - Helminths - Turbidity -Dissolved chemicals (can be removed with an additional external carbon filter) - TDS

Treatment process: Ceramic ultrafiltration and disinfection through electrolysis Inlet water criteria: Contaminated fresh water

Technical specification

Operation

The WaterPurifier is very easy to operate. One main switch will switch the unit in operation ready mode. If you tap the purified water the disinfection will start immediately. If you stop tapping water the disinfection is switched off. To generate enough pressure for the filtration process, water has to be kept in the barrel above the unit. Water pressure results in clean water. If the water barrel is empty a LED alarm light will warn you.

It is also possible to add kitchen salt (NaCl) if there is lack of it for disinfection. About 50 gram per 1000 litres is recommended. For a production of 150 m³ water per year, this will cost 7,5 kg salt. Salt can be added batchwise to each container of raw water. In one oil drum, 10 gram kitchen salt - 1 spoon). The WaterPurifier can be scaled up to 5 times in the same configuration. In that case 3 to 6 m3 water/day can be treated

The WaterPurifier is a self-contained, ready-to-use, water purification unit. There are no moving parts within the flight case as everything is build on a frame that does not move. The flight case is build so that it can be dropped on a luggage belt; normally the cases will be pitched on this. So it can survive in a lot of circumstances.

Treatment Efficiency

Input water turbidity can go up to 500 NTU and the output turbidity is < 1 NTU. The water remains safe due to the after-disinfection. Quality can be checked with an indicator strip.

Maintenance

Maintenance is simple. The filter is cleaned with a hand-powered air pump or a bicycle pump which can pump up a small air container up to 6 bar pressure. This hand made pressure is used for backwashing the membrane filter with an air pulse driven clean water backwash.

Manufacturing

The membrane and electrolysis cell cannot be manufactured locally, as they are unique part of Bright Spark. However, other parts can be locally produced.

The WaterPurifier is manufactured by “WaterPurifier”. Laboratory tests were done in Van Hall Larenstein, part of Wageningen University & Research, The Netherlands. Two weeks field tests were done at Restauracion, Dominican Republic.

The dimensions of the system are 40 x 40 x 74 cm (lxbxh), weighing 22 kg. Filtration capacity is 1 litre per minute (depending on the raw water quality). It has a flexible raw water tank capacity of 300 or 600 L/day (10-hour operation), with connections. Accessories including: hand pump 15 l/m in bucket, 220 Volt AC to 12 Volt DC adaptor; 12 Volt DC solar panel 15 pW (standard level), 12 Volt DC solar panel 150 pW (high level), oil drum 220 litres, mounting set for connecting tube/hose to a second hand oil drum, 2 m hose with GEKA connectors, tube connectors GEKA, clean water can (20 or 60 litres), water quality indicator sticks (365 units), stand for raw water tank (wood), and stand for raw water tank (aluminium).

Estimated Lifespan

The estimated lifespan is 20 years if well maintained. The membranes and the electrodes have to be replaced after 5 years.

Cost

Capital cost	Operating cost	Replacement cost	Estimated 5 year cost	Cost / metre cubed treated
€ 1.800	€100 salary per year	€ 400 for membrane €100 for electrodes		€1,21

The estimation is based on the 600 litres/day unit. The cost per litre of treated water in this case is calculated over 20 years. With 3 times replacement of membrane & electrodes. Operating cost includes salary of 1 operator, assumed to be working 1 day per week based on average annual GNI per capita in third world countries of €500 fulltime (World Bank).

Country experiences

At the moment The WaterPurifier have sales representatives in The Netherlands, Kenya, Dominican Republic, China and Egypt.