Underground Brine Detection Before Well Digging

By: Agrata Patel, Ananya Gupta and Prabudutta Mishra

May 2018

Introduction

The earlier problem statement was to design shoes for salt farmers and prevent using gum-boots during the process of salt harvesting. But during the field visit to Kutch, the team discovered that Agariyas used gum-boots. However, the living conditions and the meager income of Agariyas in Rann itself calls for additional support in their lives. Since most of the salt is harvested in Little Rann of Kutch, which is also a Wild Ass Sanctuary, Agariyas have been facing much criticism and almost no support from the Government for living in the region and hampering lives of the endangered species. The government provides them with a safety kit, including gum-boots; a government water tanker delivers drinking water every 15 days in the desert of Rann. Agariyas are recognized as monthly waged laborers by the rules and regulations of Government. This instantly refrains them from enjoying any schemes provided by the Government for the farmers (Government of India has developed a range of schemes for upliftment of farmers). With most of their salt farming being done in the free land, most of Agariyas do not own land more than one acres. Government regulations recognize a person owning and farming land more than two acres of land as a farmer. During the field visit, the team observed the living conditions of Agariyas, spending eight-nine months in the semi-arid region, in a temporary shelter made of Jute bags. Many facts such as dependency on government for clean water, scorching heat, less availability of green vegetables, no access to proper education non-transparent payments methods through cash and more to be observed.

 

User Research

Name: Shanti Bhai

Location: Rann of Kutch, Near Kharaghoda

Family Information: Shanti Bhai- Dadi Mukeshbhai- Sonalben Ram-laxman five yr. old and eight yr. old

Machines Owned: Solar Panels and AC generator

Tools Owned: Spearhead Pipe, Two Connecting Pipes, Rotating Tool

Shanti Bhai is currently living in the Rann nearest to the village Kharaghoda with his small family of 6 people. It is not very far but that does not help the severe heat they have to experience. The land is seamless. There are cracks in the dried land. The only exception is their house and the farm, their only source of income. They live in a small hut containing a room and a small kitchen. The hut is supported with bamboo sticks tied together and covered with untied jute sacks, which flutter in the breezing wind of Rann. One could see only the necessities inside his hut .Outside, a barrel of diesel is placed with his two pair of gumboots placed over it, one provided by the government and another purchased. Three khats are kept in a corner along with a Dish TV umbrella. Surrounding his house are failed bore-well digging marks, with three functioning bore wells.

 

A pump is connected to the bore-well pipes, sometimes operated by the diesel AC generator, which receives more shade than the family or the three solar panels installed beside their supposed washroom, covered with battered jute bags from three sides. While his children freely roam around in the no-vegetated area, laughing and playing, his mother cooking food for the whole family, he and his wife earn their living by harvesting salt everyday. They even have a pet pigeon with them, which his children love to play with. But little do they know how it helps his father to detect the toxic gas released while bore-well digging. His wife compromises her sanitation and menstrual habits for the work. With blisters and bruises in their hands caused due to interaction with heavy tools in salty hands and UV light, they put up a smile and earn till they can

 

. They would soon be going back to their village home when the rainy season arrives, and be back again during winter to continue the process. Shanti Bhai is currently living in the Rann nearest to the village Kharaghoda with his small family of 6 people. It is not afar but that does not help the severe heat they have to experience there. The land seems seamless, with nothing built in nearby vision. There are cracks in the dried land. The only exception is their house and the farm, their only source of income. They live in a small hut containing a room and a small kitchen. The hut is supported with bamboo sticks tied together and covered with untied jute sacks, which flutter in the breezing wind of Rann. One could see only the necessities inside his hut and not a single useless object would be noticed in his temporary abode. Outside, a barrel of diesel is placed with his two pair of gumboots placed over it, one provided by the government and another purchased. Three khats are kept in a corner along with a DishTv umbrella. Surrounding his house are failed bore-well digging marks, with three functioning bore wells. A pump is connected to the bore-well pipes, sometimes operated by the diesel AC generator, which receives more shade than the family or the three solar panels installed beside their supposed washroom, covered with battered jute bags from three sides.

 

While his children freely roam around in the no-vegetation area, laughing and playing, his mother cooking food for the whole family, he and his wife earn their living by harvesting salt everyday. They even have a pet pigeon with them, which his children love to play with. But scarcely do they know how it helps his father to detect the toxic gas released while bore-well digging. His wife compromises her sanitation and menstrual habits for the work. With blisters and bruises in their hands caused due to interaction with heavy tools in salty hands and UV light, they put up a smile and earn till they can. They would soon be going back to their village home when the rainy season arrives, and be back again during winter to continue the process.

Shantibhai’s salt farm, use of solar panel in daytime and DC generators to pump water from wells. Tools like spearhead pipe, connecting pipe, rotating

User Research

Name: Kana Bhai

Location: Rann of Kutch, Near Patadi

Machines Owned: AC generator, Two Borewell pumps

Tools Owned: Spearhead Pipe, Two Connecting Pipes, Rotating Tool, Tractor, Tractor compatible rakes

Crystalline structure of first batch of production.

Kana Bhai is now packing up and is ready to go back to his home in village. Rainy season is approaching, salt harvesting won’t be possible at this time of the year. They are leaving behind the stack of salt crystals and salt pans which was their source of income for the past eight months, knowing that it’ll be washed away completely when they come back, and they’d have to start again. They have sealed their 50ft bore well, one thing they are notoriously famous for. The sealing is done by placing piece of cloth in 30ft narrow bore and then filling the rest 20ft with mud, which they’ll be digging and opening in the next season. They own a tractor, which helps them a lot in salt harvesting.

 

Process: Salt Harvesting

Bore well digging

Well/bore well is made using manual boring process. Three iron pipes of 10 ft each are used, with one having Arrow spearhead on one end and O-ring on the other end, which are used for joining the pipes accordingly. The other two pipes contain O-rings on both ends for further connections. The ground is dug manually by inserting the spearhead pipe first and rotated using the rotating tool having tightened around the spearhead pipe. As the spearhead pipe is inserted almost completely, the connecting pipe are connected and ground is dug further, until it is 30 ft completely. A mug of water is then poured into the pipe to create vacuum and obtain brine water. This is a risky process. Before digging the bore well, the availability of water is not known. A number of dry bore wells are dug to finally obtain the one containing brine water in it. The iron pipes are then removed and a hard plastic pipe is then inserted into the bore well which is connected to the pump placed on the land. The pump is run using solar power when sun is there or using diesel accordingly. Brine water is then channeled into the prepared salt pans.

 

Transfer to Salt Pans

Two types of salt pans are used during salt farming process- one is not leveled and the other is leveled. The brine water freshly out of bore well are channeled into unlevelled salt pans interconnected using small gaps in the borders. The temperature of brine is initially 7-8 C. It is then left in the same salt pans for 10-15 days in order to increase the brine concentration and temperature. The final temperature, according to farmer is 20-25 C. There is no precise measurement of checking the temperature and thoroughly depends on the experience. After the farmer is satisfied with the brine concentration/ temperature, he channels it into the leveled salt pans using small mud pipeline connecting both.

 

Preparation of leveled Salt Pans

While brine water is in the unleveled salt pans, new large salt pans are prepared. Land area of around 500-700 ft are dug approximately 1 ft deep and moistened with the bore-well water. The farmers then press on the moistened mud barefoot to level the field, followed by rollers. It is done so as to prevent seeping of brine solution into the ground. After the whole field is evened out with almost all pores closed, the now concentrated brine water is then channeled into the pans, where it crystallizes into salt crystals.

Salt Extraction

The brine solution in the leveled salt pans crystallize into a thick layer of salt every 2-3 days. The layer is then scraped with dantala or the tooth rake in rotational motion to obtain small crystals which are then moved to the side using gantara or the flat rake. The pile of salt crystals obtained are then picked up by the truck of salt refining company for further process. The process of obtaining salt crystal is done repeatedly for 4 months, with the quality of salt decreasing in every turn. The first batch of salt obtained is of the finest quality, with the last one being the worst harvested in the batch. The price of salt decreases as the quality decreases.

Process: Salt Refining

Washing And Drying

The salt crystals brought from the Rann are unloaded in big piles surrounding the factory. Different quality of salts are kept separately and can be seen clearly from afar. Every time, half a tonne of salt are brought into the machine opening, where two or three workers are ready with the spade to insert small chunks of salt into the machine. A small opening covered by iron rods parallel aligned admits the salt crystals into the conveyor belt. The conveyor belt now carries the salt upwards into the washer. Before that, a jute rope is tied loosely in a rod which just touches the center of the salt pile in the conveyor belt. It spreads the salt evenly in the belt for similar washing. A water inlet goes inside of the washer which is evenly showered for quite a long distance upon the salt crystals. The whole process is done inside an aluminum covered machine, which ends with a fast moving roller which dries the now clean salt crystals using high centrifugal force. A water outlet goes out of the machine just before the drier starts.

Grinding

Dried crystals are now carried along in the conveyor belt downwards, which ends into a large funnel where the crystals are grinded. The mechanism of the grinding machine exactly resembles the Atta grinding machine. Out of the funnel comes slightly grained salt, the size of crystal approximate of sugar crystals, which are then carried upwards in the conveyor belt with another loosely hanging jute rope to evenly spread out the salt.

 

Addition of Iodine

A large of barrel approximately 50 L containing iodine solution is placed in one side. It has a hole on the bottom, the side of the conveyor belt. A pipe attached to it, with three holes evenly spread out over the conveyor belt release the iodine in a thin line over the grained salt. The conveyor continues carrying the now iodine contained salt upwards into another funnel shaped grinder which results into finer salt, ready to be packaged.

Packaging

Until now, the salt was untouched, all processes done by the machines although in open. Now the processed salt in the conveyer belt is carried along to another room where the salt is dropped into the either sides of the platform. Beside the platform are sit workers in groups of three along the line. The have a broken pipe of approximately 2’ radius, a weighting machine with one end containing a packaged salt of appropriate weight, a heated sealing device, and a stack of polythene packets. They take a pipe full of salt and insert it into the packets, which is then weighted in the machine to measure the amount which is accurate in 90% of the cases, due to highly curated broken pipe. The packets are kept aside the heated sealing machine, where another worker folds the packets and then presses it against the sealing machine to seal it. A worker following her inserts the pile of packets into a sack counting the numbers of packets. The sack are then sewn. The whole process of filling and sealing is quite fast and repetitive, so much that the workers are accustomed to it. The salt are now ready to go out in the market.

Problem Brief

Situated in the Little Rann of Kutch in Gujarat, are approximately 50,000 Agariyas who spend their lives extracting more than 65% of salt being manufactured in India. The salts are extracted from the underground brine solution available in abundant quantity at 30-70 feet depth in Rann. Every year, when Agaiyas come back to Rann in the month of October, they dig a few new bore wells and repair a few old ones. The process of bore well digging is quite interesting. Assuming the availability of brine underneath, the Agariyas dig the ground manually using long iron pipes, which takes two days to finish. They dig up till 20-50 ft and see weather the soil starts becoming moist or not. If it does, they continue digging to get the brine, or leave the bore well aside, marked as failed with their 2 days efforts gone in vain. During the first field visit to Rann, a farmer mentioned about digging 25 wells only to find the last one successful! It is possible to detect the availability of groundwater from the land surface before digging. Although Rann of Kutch doesn’t imply these methods , but it is possible there too.

 

Ground Resistance Method

The most cost effective solution to detect the ground water is by passing the current through the area and noting the time taken by the current to complete the circuit. The ground, even consisting of a huge concentration of salt would offer a large amount of resistance to the current. However, the presence of salt water or brine solution facilitates easy conductivity of the current, resulting in much lesser resistance offered and much less time taken.

Seismic Waves

This method is used by Oil Corporations to detect oil underground. Seismic waves are generated using large force into the ground. These waves pass through different layers of mud and get reflected by the bed-rock, just below the oil or water layer. The time taken by them to return back to surface is recorded to calculate the depth of crude oil.

 

Proton Magnetic Resistance (PMR)

This is a direct water detection method. It consists in sending electric currents into the ground, then measuring the signals emitted by the nuclei of hydrogen atoms in water molecules. It requires sophisticated equipment including proton magnetometers which can measure electromagnetic fields ; their recordings can be interpreted on site and, most importantly, the quantity of groundwater present in the rock can be deduced in a few seconds.

 

Probable Low Cost Method

One of the possible low cost methods found is based on the principle of ground resistance and conductivity of brine to detect the groundwater. The method is to measure the variations in ground resistance at different distances. When current is applied to the ground, it follows the least resistant path. And brine is a good conductor of electricity.

 

Soil Sample Collection

For the prototype testing, a model soil level of Rann has to be constructed. The team visited Shantibhai again, to collect soil and brine samples from his bore well. Soil from different depths in the Rann were starkly different from each other. The soil consists of sandy dry soil in the topmost layer followed by the black soil and then somewhat sunset yellow soil arriving at 20 ft. When we dug deeper, a clear crystal rock appears at a certain level.

Meeting with Geologists

Little Rann of Kutch has a typically different soil composition from the rest of areas and even the deserts of India. It is due to the high salt concentration of soils of Rann. Little Rann is a known source of Gypsum, Bromine and many other important minerals. Dr. N. Y. Bhatt, HOD, M. G. Science Institute explained us about the soils of Kutch. Little Rann of Kutch has seismic plates experiencing the earthquakes at intervals.

 

Prototyping

To initiate the prototyping, a model of different layers of soil present in Kutch and with the water(brine) at the deepest level, was constructed. With one feet depth of the whole soil composition and brine place in some spots in the water table model, The two iron electrodes would be inserted. Initially the soil resistance of every layer of the soil was separately measured by passing current. A drop in the variable resistance suggests the availability of water at a depth of the distance between the electrodes. By increasing the distance between two poles , we can increase the depth of the current path. The protype is intended to be developed so as to indicate the availability and non-availability of water at a certain depth by yes or no by calculating its percentage. Besides the ground resistance method, 3D- Geo mapping can be done to determine the avalibility of brine underground using cost effective IR sensors. However, there are more things to explore and determine to make the project user-friendly.

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