Why discuss Rainwater Harvesting in India?

In India, rainwater harvesting is an ancient tradition. From as far back as 4500 BC, the simplest of earthworks in Thar Desert and Rajasthan, would harvest water from the falling rain. These simplest forms of rainwater harvesting would evolve in accordance to the eco-regions within India’s borders. Using rivers, floods, monsoon, underground rivers, surface water and the earth itself, the ancient cast of pallar (water managers) have been respected for thousands of years. Rainwater harvesting in India is more than an age old tradition that varies from region to region, rainwater harvesting is an integral part of Indian identity and cultural history, that without, India would never have been.

Zeta Potential in Water Treatment Process Control

Physical processes such as sedimentation, flotation and filtration remain at the heart of most process trains for the treatment of water and wastewater. All these processes depend on the principles relating the size, density and the charge of the particles to be removed. The relative importance of the particle charge on the process efficiency is strongly dependent on the size of the particles under investigation.
Once the particles reach a certain size their mass causes a rate of sedimentation due to gravity that is sufficiently large to outweigh any effects due to the surface chemistry of the particles. However, within the range of sizes normally encountered within water and waste water processes (less than 1000 µm), there will be a fraction of fine material, less than a few tens of microns, where understanding charge interactions between the particles will assist in determining the optimum treatment regime.
The surface charge, or more strictly speaking, the zeta potential (z), is determined by measuring the particle velocity induced when a potential difference is applied across a capillary cell containing the sample (Zetasizer, Malvern Instruments Ltd.).
Zeta potential is known to be a key determinant in understanding physical processes such as flocculation and sedimentation.

low cost arsenic fluoride filters using activated alumina

You always need EXPERT ADVISE. Do contact us for your needs..

Reverse Osmosis (RO) is the most comprehensive water filtration system in that it removes the most contaminants, including flouride, arsenic,but like you said, it does mess with the PH. I bought this  activated alumina filter to the line up. Activated alumina decreases the flouride and arsenic levels in water. Other than reverse osmosis, Activated alumina filters are the only filters that I know of that remove flouride and arsenic...

Drinking Water Treatment - Activated Alumina

http://articles.extension.org/pages/31568/drinking-water-treatment-activated-alumina

Activated Alumina Arsenic filter

 “Nirmal Filter” also exists in India. It uses arsenic adsorption on an Indian-made activated alumina and it is followed by filtration through a ceramic candle. It is less expensive than a Magc-Alcan filter ($10-15 capital cost) but it needs to be regenerated every 6 months. Efficiency: 80-90% arsenic removal.

http://akvopedia.org/wiki/Arsenic_filter

Costs

Adsorption: Magc-Alcan filter

Treatment Efficiency	Production	Cost	Lifespan
Magc-Alcan: 80-85% arsenic removal. Nirmal: 80-90% arsenic removal	100 litres/hour	$35-50 capital cost	6 months to 1 year

Home Arsenic filter by DNGM RESEARCH FOUNDATION :

Read about a very simple filter for your home here:

http://www.dngmresfoundation.org/content_details.php?left_menu=43

............

Fluoride filter by INREM Foundation,Ahmedabad
 basic cost of aa is Rs 200 to 300 per filters. plus activated charcoal Rs 25 to removal traces of aa which is harmful, rest buckets say around rs 200, and other material together , basic making cost wld be around rs 600 to rs 800.

About Activated Alumina

Activated alumina is a filter media made by treating aluminum ore so that it becomes porous and highly adsorptive. Activated alumina will remove a variety of contaminants including excessive fluoride, arsenic and selenium. The medium requires periodic cleaning with an appropriate regenerate such as alum or acid in order to remain effective.

It is interesting to note the type of physical properties of the activated alumina are never discussed in these articles, although they may have a significant effect upon the fluoride or arsenic removal performance. Other factors likely to have an effect upon alumina performance are flow rate, other ions in the water to be treated, pH of the water, and the method and conditions of regeneration.
Activated Alumina

The granular activated alumina used in the evaluations discussed in this report is 14 X 28 grind activated alumina (AA). This is a transition alumina with a high surface area (>300 m2/g), which makes it especially suited for adsorption of certain species. It is a fairly high purity alumina with a pore volume of ~0.5 cc/gm and a bulk density of 46 lbs./ft3. The 14 X 28 S product is a similar activated alumina but in a spherical form. The granular alumina has the advantage of being available in smaller sizes, making the internal active surface of the alumina more readily available. However, the spherical alumina has the advantage of a lower pressure drop in packed bed (i.e., down flow) systems. The fluoride removal data described were obtained with laboratory scale experiments using 14 x 28 mesh size granular alumina in a packed column.
Regeneration Methods

Most arsenic and fluoride removal applications are long term and necessitate regeneration of the alumina. There are three known methods for regeneration: (1) NaOH/H2SO4, (2) Al2 (SO4)3 and (3) H2SO4.
Regeneration of saturated alumina is carried out by exposing the medium to 4% caustic soda (NaOH), either in batch or by flow through the column resulting in high-arsenic-contaminated caustic waste water. The residual caustic soda is then washed out and the medium is neutralized with a 2% solution of sulfuric acid rinse. During the process about 5–10% of the alumina is lost and the capacity of the regenerated medium is reduced by 30–40%. The activated alumina needs replacement after 3–4 regenerations.http://www.tramfloc.com/tf133.html

ARSENIC REMOVAL TECHNOLOGIES
http://www.sswm.info/content/arsenic-removal-technologies

Activated Alumina

Activated alumina (Al₂O₃) has a good sorptive surface, in the range of 200-300 m²/g. The large surface area gives the material a very large area for adsorption of arsenic. When water passes through a packed column of activated alumina, the impurities including arsenic present in water are adsorbed on the surfaces of activated alumina grains. Eventually, the column becomes saturated, first at its upper zone and later downstream towards the bottom end, and finally the column gets totally saturated. Regeneration of saturated alumina is carried out by exposing the medium to 4% caustic soda (NaOH) either in batch or by flow through the column resulting in highly arsenic-contaminated caustic wastewater. Arsenic removal by activated alumina is controlled by pH and the arsenic content of water. The efficiency drops as the point of zero charge is approached and at pH 8.2 where the surface is negatively charged, the removal capacities are only 2-5% of the capacity at optimal pH (CLIFFORD 1990). Some examples of activated alumina based sorptive media are: the “BUET Activated Alumina”, the “Alcan Enhanced Activated Alumina” and the “Apyron Arsenic Treatment Unit”.

Important Weblinks

http://techtv.mit.edu/ [Accessed: 04.01.2010]

Video produced by Global Water Trust (2008), showing arsenic scenarios and the implementation of KanchanTM Arsenic Filter.

http://web.mit.edu/ [Accessed: 04.01.2010]

This weblink provides information on WATSAN and researches on Household water treatment technologies including KanchanTM Arsenic Filter by MIT.

http://www.eng-consult.com/ [Accessed: 23.10.2010]

This web link contains different articles and an overview of several arsenic removal methods with their advantages and disadvantages.

http://www.who.int/ [Accessed: 20.10.2010]

This web link contains a general discussion on different arsenic removal options for controlling risk.

http://www.youtube.com/ [Accessed: 13.01.2011]

This web link connects to a video on arsenic treatment by coagulation/filtration processes.

FOUR KALSHI FILTER AT VILLAGE( Removes Iron, Fluoride, Arsenic)

Description 

A homemade, four-pitcher filter unit, one of the simplest and most inexpensive ways treat drinking water. The first pitcher contains coarse sand. The second contains  activated alumina, third pitcher contains activated carbon, and the fourth collects the filtered water. 

A sari cloth is sometimes used as an additional filter between the top 2 kalshi. 

Benefits

• Simple
• Excellent microbial removal, Iron Removal,Fluoride and Arsenic Removal
• Can be constructed of local materials
• Cost:Minimum

Drawbacks

• Fragile
• Low flow (1-2 litres / hr.)
• Irregular flow rate, requires frequent cleaning
• Availability of activated alumina

Cost :Rs.500/=

Operating & Maintenance: replacement of activated alumina after two months

CONTACT : Saleem Asraf Syed Imdaadullah, 09899300371(Delhi)

                     Rakib Hussain (Mobile: 9859171561,Guwahati.)

ENVO PROJECTS,NEW DELHI. www.saleemindia.blogspot.com