Low Cost High Quality Arsenic Filter

Patent Filing No.: 430/KOL/2013

Arsenic contamination in groundwater has become a global issue, with more than 200 million are potential at risk, as reported by recent UN report. There are several reasons of arsenic contamination apart from anthropogenic sources which includes (i) use of phosphate fertilizers and pesticides which leaches through the sub-soil and reduces the arsenic binding capacity of the rocks (ii) oxidation of arseno-pyrites present in rocks due to excessive withdrawal of groundwater and (iii) untreated release of industrial effluent and wastes. There are widespread reports of arsenic poisoning of ground water in Bangladesh, Mexico, Vietnam, Western United States, Taiwan, India, Canada and more than 50 countries which entailed above World Health Organization limit for drinking water of 10µg/l. Arsenic poisoning is severe along the Gangetic plains in our country. In certain parts of West Bengal, arsenic concentration as high as 500 to 2000 ppb has also been found. Arsenic is found in +3 and +5 state, both of which are toxic for human health.

          Adsorption has been found to be the most suitable mechanism for removal of arsenic. However, the capacity of the adsorbent and its regeneration determines the crux of the problem. Almost all the adsorbents that are available or developed till now require regeneration because of its low capacity, which ultimately releases the arsenic back to the environment, thereby becomes an anthropogenic source. Naturally occurring laterite and ferro-manganese ores exhibits arsenic adsorption. However, the capacity of these materials needs to be increases for practical application.

          The work on removal of arsenic using naturally occurring laterite has been initiated in the Department of Chemical Engineering, IIT Kharagpur under the leadership of Prof. Sirshendu De and his students back in 2006. The idea of using laterite came by examining the geographical contamination profile in West Bengal. It was observed that seven districts along the Ganges (Malda, Murshidabad, Nadia, South and North 24 Parganas, Part of Burdwan, Kolkata) have been badly affected by arsenic contamination of groundwater. On the other hand, districts in south-western and western parts of West Bengal (Midnapore, Bankura, Purulia) do not have this problem. It has been found that reason lies in the geological nature of the soil of these regions. The red colored lateritic rock in these parts contains alumina and iron oxide components which have a natural capacity to adsorb arsenic species. The present innovation details with acid activated based laterite adsorbent (Development of high capacity and cost effective arsenic adsorbent using modified laterite, Filed 614/KOL/2009) which has high arsenic adsorption capacity (both arsenite and arsenate).

Salient features of the technology

(i)      The total removal capacity of arsenic is 32.5 mg/g, which is highest compared to all other available arsenic adsorbents.

(ii)     Ultra low cost of the filter media appropriate for the socio-economic conditions of our country. Filtered water can be produced at 2 paisa per liter ($1.2 for 1000 gallons).

(iii)    Power is required only to operate the pump to lift water into overhead tank. Flow in the filters is by gravity. In case of household filter, no power required.

(iv)    Removal of arsenic, iron and bacteriological contamination together in a single unit. The filter is capable to remove iron below the permissible limit in drinking water (0.3 ppm) and remove more than 98% of pathogenic contaminants.

(v)     The filter bed consists of different layer of materials including bacteriostatic activated carbon, charcoal, fine granular sand, activated laterite and raw laterite.

(vi)    No interference from sulphate, chloride, magnesium and iron ions are observed.

(vii)   Works over wide range of pH 5.5 to 8.0.

(viii)  The total arsenic concentration in the filtrate is always less than 10 ppb (WHO limit).

(ix)    The filter life 5 years in the worst possible condition. The filter will be more if the influent arsenic concentration is less.

(x)     No regeneration or backwashing is needed during its lifetime, which makes this technology unique and unparallel.

(xi)    The empty bed contact time is 7.2 hours which is necessary for the adsorption to occur.

(xii)   The adsorbent binds arsenic by strong chemisorption. The spent adsorbent meets TCLP protocol and can safely disposed. It can be used for making bricks, road lining, pavements, cell filling, etc. Therefore, this adsorption provides the ultimate solution for treatment of arsenic contaminated water.

(xiii)  Easy maintenance and operation.

(xiv) The cost of domestic filter would be in the range of 2500-3000 rupees (40 to 50 USD).

Units Deployed:

Total number of Household units deployed so far: 16

Lalgola, Mushidabad, West Bengal (one unit in August 2012)

Behrampur, Murshidabad, West Bengal (two units in August 2012)

Baruipur, South 24 Paraganas, West Bengal (one unit in Sep 2012)

Rajarhat, North 24 Parganas, West Bengal (two units in Oct 2012)

Bamangachi, Barasat, North 24 Parganas, West Bengal (one in March 2011 and remaining 8 in Oct 2012)

Habra, North 24 Parganas, West Bengal (one unit in Sep 2012)

Total number of community filters deployed: 3

Kashinathpur free primary school, Rajarhat, North 24 Parganas, West Bengal (installed in Oct 2012) - 500 L/day capacity

Ambika Girls High School, Rajarhat, North 24 Parganas, West Bengal (installed in December 2012) - 1500 L/day capacity

Choudhuar Primary School, Manikchawk Block, Malda, West Bengal (installed in December 2014) - 800 L/day capacity.

The technology has been developed, demonstrated and deployed in field with active support from Department of Science & Technology, Govt. of India and UNICEF, West Bengal. Technology is transferred to one company. 

The contributors to this work are –

Sourav Mondal, Barun Kumar Thakur, Kuldeep Yadav, Mrinmoy Mondal, Raka Mukherjee, Anirban Roy, Biswajit Barman and Sirshendu De, Department of Chemical Engineering, IIT Kharagpur.

Uniaxial MEMS piezoresistive accelerometer

Patent filing no.: 737/KOL/2013

Technology title: Uniaxial MEMS piezoresistive accelerometer with enhanced cross-axis signal reduction

1.    A brief description of the technology

MEMS accelerometers are micromechanical inertial sensors used for aerospace, civil, automotive, industry and consumer electronics applications. Uniaxial MEMS piezoresistive accelerometers are primarily used in strategic domains such as navigation and guidance of aircrafts and ballistic missiles. Our technology involves the conceptualization of a single-axis MEMS piezoresistive accelerometer variant designed for inertial navigation systems with enhanced crosstalk (signals along axes other than the primary sensing axis) rejection. Crosstalk is a significant aberration in accelerometer output and can severely interfere with precise definition of position and orientation which can result in catastrophic disasters. The technology is aimed at creating a system which can operate efficiently within an inertial measurement unit.

2.    Commercial prospect of the technology

Accelerometers are indispensable in applications involving motion, ranging from kinesiological studies to motion guidance in ballistic systems. It is expected that important industrial sectors such as automotive, aerospace, and strategic should benefit from such a technology, not to mention the increasing applications of MEMS inertial sensors in the field of consumer electronic gadgets.

3.    Advantages of this technology over the already existing methods

Highly precise uniaxial sensing with robust linearity, appreciable sensitivity due to the mechanical design layout and added flexibility of electrical design layout on either wafer surface. Extremely low-noise and ~1000g shock survivability under packaged conditions provide further value addition. The fundamental conceptualization of the design has been on the basis of measurements carried out on a slightly older variant which exhibits appreciable performance.

4.    A summary of the technical details involved

The conceptualized device is a precisely bulk micromachined silicon-on-insulator micromechanical piezoresistive accelerometer with aircraft navigation being the primary application. Ion implanted piezoresistors connected through a metalized Wheatstone bridge which serves as the basic signal transduction element. Deep reactive ion etching is used for realization of the mechanical structure of the sensor. The low noise property of such sensors is achieved through proper doping and bulk micromachining of the structure while the operational mechanism ensures high linearity.

5.    Future prospects of the technology

With advancement in the automotive and aerospace sector, inertial navigation systems are becoming increasingly complex with a constant need for precision sensors to meet such requirements. As with any system, improvements are possible when the application is specifically defined and it is expected that this technology will prove to be a step in the right direction for the development of robust inertial sensors.

Inventors: Prof. Tarun Kanti Bhattacharya, Mr. Anindya Lal Roy

Storage and extension of shelf life

Ultrafiltration membrane for cold sterilization of bottle gourd juice (Lagenaria siceraria) for extended shelf life and method thereof (724/KOL/2014)

A polyacrylonitrile (PAN) based hollow fibre membrane for clarification of tender coconut water with desired storage stability (768/KOL/2014)

Patent: 724/KOL/2014

1. Brief description:

In this work, an appropriate characterization of the hollow fiber membranes has been identified that has application in clarification of bottle gourd (Lagenaria siceraria) juice with long shelf life. 44 kDa molecular weight cut off membrane (MWCO) was found suitable for this purpose. A membrane based on polysulfone (PSF) was formulated to achieve this goal. The clarification process removed the sites of potent bacterial growth. Thus, this process increases the shelf life of bottle gourd juice significantly without adding any preservative after aseptic packaging. Also, since there is no thermal sterilization, browning of the bottle gourd juice does not occur. The final product from ultrafiltration is rich in polyphenol (anti-oxidant), sugar, potassium and sodium. The process is very economic, since the hollow fibers used are indigenous and very low cost (Indian patent 582/KOL/2011). The final product can be stored for 8 weeks under refrigerated condition without deterioration of the taste or aroma of the product.

2. Commercial aspects of the technology & Industries benefiting from it

Generally, processed bottle gourd juice is produced in very small scale over the world. Shelf life of the untreated bottle gourd juice is very less, about 1 to 2 days. Usually, the shelf life of the bottle gourd juice is increased by hot sterilization, commonly known as pasteurization. But, this process deteriorates the juice quality, taste and its aroma.

In the present market, bottle gourd juice is not commercially available. In India, it is a common practice to intake bottle gourd juice without any further clarification. This process of intake is not suitable as bottle gourd contains a high amount of fibrous mass which is of no use to the body.

The patented process provides a much clarified product for intake without any suspended solid and keeping intact almost all the nutritional parameters. So one can get the advantage of a whole bottle gourd fruit by consuming only 100-200 ml of the clarified juice.

3. Advantages of this technology

·         Unique formulation of membrane removes potent sites for microbial growth.

·         Since, hot sterilization is not done the aroma and the flavour or aroma of the bottle gourd juice was not deteriorated.

·         Since, no additional preservative was added in the juice, the taste of the product was same as natural bottle gourd.

·         The process was carried out in hollow fiber modules, which are very cost effective and easy to scale up for industrial production.

4. Summary of the technical details

Ultrafiltration experiments was conducted for 3 transmembrane pressure drop in the range of 35 to 104 kPa and three cross flow rates (5 to 15 l/h). Various properties were measured. Finally, a detailed storage study was done for 8 weeks after which the quality of the juice was deteriorated. By analyzing the physico-chemical properties of the filtered juice it was seen that the juice meets all its standard qualities like aroma, taste, odour and likeability even after 8 weeks of refrigerated storage. Also the nutritional quality of the juice was almost constant.

Bottle gourd juice contains high amount of fibres, thus it is more susceptible to deterioration. Also, since the amount of suspended solid is more, membrane fouling is more prominent. Hence, first a prefiltration process of microfiltration was employed to reduce the solid content. The microfiltered juice was then subjected to ultrafiltration by a 44 kDa PSF membrane. The optimum operating condition, based on productivity, was found to be 104 kPa and 15 l/h for the ultrafiltration of bottle gourd juice within the range of operating conditions studied herein. The permeate flux obtained at this operating condition was 45 l/m².h.

 The storage study was conducted for 8 weeks under normal refrigerated conditions and it was seen that all the physic-chemical properties, especially nutritional qualities like sodium, potassium, TSS and polyphenol show very less deviation from the initial value. So the sample was perfectly alright till 8 weeks of storage in aseptic packaging.  The storage study was carried out in laboratory conditions and significant results were obtained, that even after 8 weeks the juice was almost same as the original one, i.e., the taste of the juice was almost same as in zeroth week.

  5. Future prospects of the technology:

The technology is off-the-shelf i.e. it could be brought to market with nominal investment.

Patent: 768/KOL/2014

1. Brief description:

In this work, an appropriate characterization of the hollow fiber membranes has been identified that has application in clarification of tender coconut water with long shelf life. 44 kDa molecular weight cut off membrane (MWCO) was found suitable for this purpose. A membrane based on polyacrylonitrile (PAN) was formulated to achieve this goal. The clarification process removed the sites of potent bacterial growth. Thus, this process increases the shelf life of tender coconut water significantly without adding any preservative after aseptic packaging. Also, since there is no thermal sterilization, browning of the coconut water does not occur. The final product from ultrafiltration is rich in polyphenol (anti-oxidant), sugar, potassium and sodium. The process is very economic, since the hollow fibers used are indigenous and very low cost (Indian patent 582/KOL/2011). The final product can be stored for 18 weeks under refrigerated condition without deterioration of the taste or aroma of the product.

2. Commercial aspects of the technology & Industries benefiting from it

Generally the shelf life of tender coconut water is increased before packaging by either hot sterilization or addition of preservative. This deteriorates the quality of the final product, taste and aroma.

This patent discusses cheap, affordable solution, for the first time, to extend the shelf life of tender coconut water without any heat treatment or addition of preservatives. The clarification process removed the sites of potent bacterial growth without any thermal sterilization. Thus, this process increases the shelf life of tender coconut water significantly after aseptic packaging without adding any preservative or heat treatment. The final product from ultrafiltration is rich in polyphenol (anti-oxidant), sugar, potassium and sodium. It satisfies the criteria of novelty, non-obviousness and usefulness.

The invention has a tremendous commercial implication in the Indian and developing country scenario alike. Coconut is only abundant in tropical regions near coasts. So there is a high demand for coconut in the inland. This process provides a suitable method for preserving all the nutritional qualities of the coconut water without adding any external chemicals.

3. Advantages of this technology

·         Unique formulation of membrane removes potent sites for microbial growth.

·         Since, hot sterilization is not done the aroma and the flavor of the coconut water was not deteriorated.

·         Since, no additional preservative was added in the juice, the taste of the product was same as natural coconut water.

·         The process was carried out in hollow fiber modules, which are very cost effective and also very easy to scale up for industrial production.

4. Summary of the technical details

Ultrafiltration experiments was conducted for 4 transmembrane pressure drop in the range of 21 to 84 kPa and three cross flow rates (5 to 15 l/h). Various properties were measured. Finally, a detailed storage study was done for 18 weeks after which the quality of the juice was deteriorated. By analyzing the physico-chemical properties of the filtered juice it was seen that the juice meets all its standard qualities like aroma, taste, odour and likeability even after 18 weeks of refrigerated storage. Also the nutritional quality of the juice was almost constant.

         Young tender coconut water has very low suspended solid, so the membrane fouling is very less. Mature tender coconut water has a high amount of suspended solid and hence the fouling is more. The productivity for the membrane is 30 l/m².h at the optimum operating condition of 84 kPa transmembrane pressure and 10 l/h cross flow rate.  The storage study was conducted for 18 weeks under normal refrigerated conditions and it was seen that all the physic-chemical properties, especially nutritional qualities like sodium, potassium, TSS and polyphenol show very less deviation from the initial value. So the sample was perfectly alright till 18 weeks of storage in aseptic packaging.  The taste analysis shows that the taste was perfectly like the original one after 18 weeks. It has been confirmed by a series of experts that the taste was good and all showed positive purchase intention. The storage study was carried out in laboratory conditions and significant results were obtained, that even after 18 weeks the juice was almost same as the original one, i.e., the taste of the juice was almost same as in zeroth week.

   5. Future prospects of the technology:

The industrial partners of this project, M/s Technorbital Advanced Materials Pvt. Ltd.  are going ahead with the commercialization of the technology.