Community Based
Solar DFU system

.Community based DFU system

Desire energy manufacture and supply De-Fluoridation units, for the fluoride effected areas. Desire De-Fluoridation unit are available on media based (Bio F/AA) and also with Automatic Fuoride Removal Unit (ARFU)  (approved by MNIT) based on Electro-coagulation – a patented technology of Desire Energy.  Desire De-Fluoridation unit have capacity to reduce fluoride to 0.5 PPM even from 15 PPM  fluoride content in raw water. We have rapidly installed more than 3000 units till date and we are running these units successfully in various parts of the country

These De-Fluoridation units can work without/with conventional electricity and can be clubbed with solar energy based pumps to provide disruption free end-to-end solutions to the cosumers.

.Rajasthan- An outlook on pure water crises

Rajasthan, an arid state is heavily dependent on groundwater which is directly related to rainwater. With more than 90% of water is brackish out of which 50% contains high level of fluoride particles, the state poses great threat of water borne diseases. Excess of fluoride in water can cause dental fluorosis, skeletal fluorosis, thyroid and neurological problems which hampers and overall physical and mental growth of child and mother during pregnancy. Besides fluoride, there are other contaminants which are found in water in the form of solid waste, chloride and plastic that too put a negative impact on the body. Other TDS (Total dissolved Solids) such as calcium, magnesium, potassium, chlorides, bicarbonates and sulphates are also found in drinkable water. According of BIS (Bureau of Indian standards) the minimum TDS that a potable water must have is 30 PPM (parts per million) and should not exceed 500 PPM in order to stay the water fit for drinking. Unfortunately constant exposure of water to chemicals and other poisonous substances have increased the level of TDS close to 5000 PPM.

.Community based DFU system

With consistent innovation and hard work, desire has come up with a distinctive solution to the water problem. In order to make it pure and drinkable, Desire has introduced a DFU system (Defluoridation system) which runs on solar energy and converts fluoride rich water into potable one. This system purifies water contains high concentration of Fluoride in it. The community based DFU system is basically installed in the areas where the concentration of Fluorides and other solid impurities are high such as villages, Gramin blocks and remote areas where connectivity of electricity is not available. Owing to the quality output and high performance for long run, DESIRE has successfully installed more than 3000 units of DFU system across India.

.Desire Have A 2 Technology

1)  BIO-F technology 

Bio-F De-fluoridation System:

Why Fluoride Removal?

Excessive Fluoride in Water is a menace. The permissible limit in drinking water is 1.5 ppm in India where as it is much lower as per World Health Organization Standards. Excess Fluoride in Water can cause several diseases such as:
• Dental Fluorosis
• Skeletal Fluorosis – Arthritic pain, spine rigidity, mal-shaping of bones, etc. When you ingest Fluoride, only about 50 comes out and the remainder is stored in the bones, which accumulated over a period, causes severe physical problems.
• Cancer
• Genetic Damages
• Fluoride is more toxic than lead and slightly less toxic than Arsenic.

Why Bio-F?

• Safe-No Chemical required.
• High & steady adsorption
• High fluoride removal efficiency
• Stable regeneration capability
• Cost effective
• Tested & certified by various leading labs across the country
• Safe, Simple regeneration.

Bio-F Regeneration Methods – Convenient Safe Simple

Regeneration Method 1 – Keep the media dissolved in alum solutions for 2-3 hours. Then the drain alum solution out and rinse with fresh water.
Regeneration Method 2 – The new generation method develop by us, require you to just insert hot water at > 70 degree C or pass steam through the media and then risen the fresh water.

BIO-F v/s Activated Alumina

No. Activity Activated Alumina OxiMax Bio-F
De-fluoridation capacity
1 mg/g
3-4 mg/g
Regeneration Process
Regeneration by exposing to 4% caustic soda (hazardous chemical) difficult to carry out regeneration onsite. Must be carried to regeneration centre.
Regeneration using alum or hot water/ steam >70oC. Can be easily carried out at site.
Wastewater contaminated with Fluoride thus going back to ground at the same location.
No Fluoride in wastewater.
Neutralization required with sulphuric acid after regeneration again hazardous chemical use.
No neutralization necessary.
Number of Regenerations Possible
3-4, after which media needs replacement.
15-20 times


In India, an estimated 62 million people, including 6 million children suffer from fluorosis due to consumption of excess fluoride contaminated water. As per BIS 10500, 2004 and WHO guideline the desirable limit of fluoride in drinking water is 1.0 mg/L, which can be extended to 1.5 mg/L in the absence of alternate source.
automated Fluoride removal process is a water purification system suitable for fluoride affected area with water containing excess fluoride. The defluoridation process is based on the principle of electrolysis, using aluminium plate electrodes placed in the raw water containing excess fluoride. During the electrolysis, anode gets ionized and fluoride is removed by complex formation, adsorption, precipitation,coagulation and settling.

The present invention relates to an automated Fluoride removal unit and more particularly an automated Fluoride removal unit based on the principle of electrolysis by passing Direct Current (DC) obtained from solar photovoltaic system; through aluminium plate electrodes placed in fluoride containing water, formation of complex with fluoride in water followed by adsorption and removal by settling.
The conventional automated Fluoride removal methods are divided into two basic types depending upon the mode of action: based on chemical reaction with fluoride and absorption process and is completely manual.The conventional De-fluoridation process based on absorption process have no provision of LIVE monitoring.The conventional defluoridation processes does not reduce bacterial contamination
The main object of the present invention is to provide fully automated electrolytic defluoridation unit which is easy to operate and can be monitored LIVE and requires less maintenance.Another object of the invention is to provide a technique which is capable of removing fluoride and reducing total dissolved solids, which include hardness, nitrate and microbial contamination from raw water with excess fluoride concentration.Another object of the invention is to provide fluoride safe water, without any chemical addition for removal of fluoride. Another object of the invention is to provide an electrolytic defluoridation process, capable of removing fluoride to safe limit of <1.00 mg/L which is portable and palatable in taste.

Salient Features

• Removal of fluoride by active species of hydroxide of aluminium produced by passing DC power through aluminium electrodes
• Simple to fabricate, easy to operate with minimum maintenance
• Suitable for treatment of raw water with fluoride concentration upto 10 mg/L
• Produces potable water with palatable taste as against the other available chemical treatment methods
• Quantity of sludge produced is much less (60-70%) than conventional treatment methods
• Simultaneous reduction in bacterial contamination in treated water
• Cost of treated water Rs. 45-60 per 1000 liter
• Capacity : 300 Ltr per batch in 30 minutes.