Technology

Water is life, essential for daily sustenance and healthy living. With plummeting groundwater levels, contamination of water sources and increasing consumption, challenges in the water sector have increased manifold. Safe, sustainable and affordable water in the face of growing water needs is a severe challenge. With fresh water supplies already hard pressed to meet growing demand, technology plays an important role in managing and using the limited available water in a cost effective and critical manner.

Water contamination occurs both due to human activities and natural processes. Depending upon the purpose for which the water is needed--municipal, industrial or agriculture--treatment is carried out. The technology used will depend upon the current water quality, future standards required and economics of the treatment method. Water treatment removes contaminants that may be biological, physical or chemical in nature. 

Various water treatment technologies are present that purify polluted water by removing undesirable chemicals or biological contaminants and making it fit for human consumption. Use based classification of surface waters in India has been laid down by the Central Pollution Control Board (CPCB). The details of the permissible and desirable limits of various parameters in drinking water as per Bureau of Indian Standards (BIS) standard specifications for potable water are also detailed in the IS 10500:1991

Water treatment plants use technologies to produce water that is safe both chemically and biologically, and that is appealing in terms of colour, odour and taste. The control point for water quality determination must be the consumer's tap and not the treatment facility, which means that the water quality must not be impaired during transmission, storage and distribution to the user. The treatment methods at the plant include aeration, coagulation and flocculation, sedimentation, filtration and disinfection.  Some of the prevalent water purification & treatment technologies are listed below.

  • Capacitive Deionization (CDI) is a technology where ions are removed from water by passing it through a spacer channel with porous electrodes on each side
  • Ozonation is a chemical water treatment technique based on the infusion of ozone into water
  • Ultraviolet technology uses Ultraviolet light, just like sunlight, to kill micro-organisms present in the water
  • Reverse Osmosis (RO) is a technology that removes a large majority of contaminants by pushing the water under pressure through a semi-permeable membrane
  • TERAFIL is a burnt red clay porous media used for filtration & treatment of raw water into clean drinking water, developed Council of Scientific & Industrial Research (CSIR), Bhubaneshwar 
  • OS- Community scale Arsenic Filter is an organic arsenic filter, developed by IIT Kharagpur
  • Filtration methods that may include rapid/ slow sand filters remove dirt, rust, silt, dust and other particulate matter from water
  • Solar water purification systems 

Water treatment technologies for safe, potable water in rural areas that includes Capacitive Deionization Technology (CDI) using carbon aerogel, solar operated groundwater treatment plants and electro chlorination are described in a booklet ‘Compendium of innovative technologies on rural drinking water & sanitation’ by the Ministry of Drinking Water and Sanitation. 

Domestic drinking water filtration methods vary depending upon the method of purification used, the degree of ‘purity’ required, and the type of contaminants in the water. No one technology will fulfil all criteria--there is no ‘silver bullet’ solution. Some of the more popular methods for Household Water Treatment & Safe Storage (HWTS) options includes boiling, SODIS (Solar disinfection), Chlorine Tablets, Liquid Chlorine (online, Biosand filters, Flocculent treatment, Ceramic candle, Filter combinations, Pureit filters, Ultra Violet (UV) filters, Reverse Osmosis (RO) and Ion Exchange (IEX).

For more on water purification systems, click here.

Domestic Greywater Recycling Water filtration technologies

Any used water, other than sewage from toilet basins that exit a house or apartment complex, is referred to as sullage or greywater. This is mostly made up of water used in bathrooms and kitchens, constituting the bulk--nearly 60%-70%--of the total volume of water used in a day. 

Before underground sewerage was introduced in most cities, water followed a cyclical route. Water was drawn from dug wells within the premises. Refuse water from the bathrooms and kitchen was let out into the garden while water from the closets reached septic tanks. The soil treated the greywater and sent it back into the ground, thereby closing the household water consumption-reuse loop.

Contrary to popular belief, greywater is largely free from pathogens. As it is mostly made up of easily degradable organic waste and chemicals from cleaning products, it can be purified and reused in-situ with minimal effort. In many homes and apartment complexes, sending this perfectly reusable resource out of the plot along with sewage common-sight. Greywater can be brought back into the water cycle by employing simple biological and mechanical filtration techniques.

There are two basic requirements apart from the necessary plumbing arrangements for treating domestic wastewater:

  1. Open soil space
  2. Water loving plants

Water from bathrooms and kitchens can be diverted through a dedicated pipeline into the plant bed set aside for the treatment process. Here, the nutrients present in the waste water are absorbed by water loving plants such as Canna or Cyperus while the soil bacteria polish off the organic waste from the water. 

  • Constructed wetlands – These wetlands are created to replicate the process of bio-filtration that occurs in a natural setting. Here, the water is purified using two media, the planted surface and the gravel bed underneath. 
  • Reed bed treatment plants – A smaller version of the constructed wetlands, reed beds are perfect for individual houses and smaller complexes.
  • Mechanical filtration – Mechanical systems such as sand filters and pebble flow systems can be used to help filter out waste from the water by separating the discernable solids from the liquid component. 
  • Lava filters – These pebble filters are a combination of both biological and mechanical systems where the stones act as support structures for microorganisms that help break down the waste. 

For more on the basics of rainwater harvesting and greywater recycling, refer Self reliance in water: A book by Indukanth Ragade.  

Sewage treatment--Municipal and Industrial

Waste water flowing out of urinals and toilet closets are referred to as ‘blackwater’ or sewage. Blackwater cannot be treated in the same way as greywater as the former contains a heavy pathogen load from the fecal matter suspended in it. Sewage from towns and cities flowing directly into water bodies is one of the major reasons for water pollution.

Municipal wastewater treatment plant, Yelahanka, Bangalore

While City Corporations are in charge of laying underground sewerage pipes to collect, channel and treat sewage, localities outside city limits have a greater responsibility of managing their own waste. Apartment complexes and townships mostly rely on small scale sewage treatment plants (STP) to treat their waste.

Wastewater can be treated either in the presence or absence of oxygen. While aerobic digestion involves the breakdown of waste by microorganisms in the presence of oxygen, anaerobic systems work in its absence. Various types of processes are used to treat both domestic and industrial waste water such as:

  • Activated Sludge Process where biological agents such as bacteria are used in the presence of air to oxidise the nutrients present in the sewage 
  • Sequencing Batch Reactors help equalize, aerate and sediment waste water in timed batches by mixing it with activated sludge and oxygen to reduce the organic load 
  • Membrane Bio Reactors provide a higher degree of organic and solid removal by combining the principles of both mechanical filtration and biological digestion to treat municipal waste 
  • Moving Bed Bioreactors are mainly used for aerating and treating high-strength wastewater where several floating polyethylene bio-films move in suspension provide surface area for the nutrient-digesting bacteria to grow 
  • Trickling filters are low-cost, aerobic systems made up of a fixed bed of gravel, rocks and moss over through sewage is passed to remove the nutrient material in the suspension 
  • Facultative aerated lagoons are shallow ponds where the sewage is allowed to with the atmospheric oxygen in the upper layers while the sludge settles down at the bottom 
  • Waste stabilisation ponds, categorized into three broad types – anaerobic, facultative and aeobic depending on the oxygen use intensity – help in reducing nutrient content and polishing waste water to re-use quality 
  • Up-flow anaerobic sludge blanket digestion treats wastewater in the absence of oxygen where the feed enters the tank through the bottom and flows upward as the bacteria present in the sludge digest organic the matter 

The CPCB publication on the status of sewage treatment in India throws light on the performance of sewage treatment plants across the country and the technologies currently being used in them. The status of waste water generation and treatment across the country is also available on the ENVIS Centre on hygiene, sanitation, sewage treatment systems and technology. 

  • Supreme Court question authorities on why manual scavenging still prevails Taking note of four to five deaths every month due to manual scavenging, the Supreme Court came down heavily on the government for failing to provide protective gear to people engaged in manual scavenging and cleaning of sew...
    swatiposted 3 months 4 weeks agoread more
  • In 2014, the Government of India launched the Swachh Bharat Mission (SBM) to accelerate efforts in achieving universal sanitation coverage. The issue of access to safe drinking water and sanitation facilities also became a major Sustainable Development Goal (SDG-6) when the United Nation set 17 glob...
    priyadposted 3 months 4 weeks agoread more
  • Dear Sir, I am living in a hilly area and I have to take water from 130 meter down. There is an open well and 1.5 hp submersible pump, my problem is the delivery hose. I used green coloured hose and after 3 months its broken, now I want to replace it. Can you suggest me the proper hose to use for t...
    Anonymous (not verified)posted 4 months 2 days agoread more
  • Spatial and temporal information of agriculture, forest, topography, land use change, climate and socio-economic factors are very useful in the planning and implementation of Natural Resource Management (NRM) programs. Despite this relevance, quantitative information on these variables is not widely...
    priyadposted 4 months 5 days agoread more
  • Why clear water reservoir is having only 15 years of design period? Source: CPHEEO
    Anonymous (not verified)posted 4 months 6 days agoread more
  • New Delhi, September 17 (India Science Wire): A new technology developed by Indian scientists for ecological restoration is helping in revival of mangroves degraded due to rising sea levels, climate change and human intrusion in the Sunderbans in West Bengal.  Ecological restoration means revi...
    priyadposted 4 months 6 days agoread more
  • NGT orders DDA to ensure farming on the Yamuna floodplains is stopped by 2020 The National Green Tribunal (NGT) has ordered the Delhi Development Authority to ensure that farming of fruit and vegetables on the Yamuna floodplains is stopped and the area is restored into a biodiversity area. The trib...
    swatiposted 4 months 6 days agoread more
  • Telangana government, tribals stand against proposed uranium mining in Nallamala forests A few months ago, the environment ministry gave in-principle approval to the Uranium Corporation of India Limited (UCIL) to begin exploration for uranium in the Nallamala forest, which stretches across the stat...
    swatiposted 4 months 6 days agoread more
  • We have 235 feet borewell at home and we use texmo compression motor to pump. We observed that the water is not pumped up to the water tank from past few days. We could see meagre water in tank even if motor is running for more than an hour. We already had a borewell with 90ft depth and since there ...
    Anonymous (not verified)posted 4 months 1 week agoread more
  • Choked by sewage and effluent discharge, lakes in and around Indore are in a terrible state and in need of restoration. A bustling city in central India, Indore was declared the cleanest city in India three years in a row. After cleaning the streets and its garbage landfill area, it has now turned i...
    Amita Bhaduriposted 4 months 1 week agoread more
  • Hello, I have a new borewell in Tumkur, Kallambella, where I have received water of 1.5 inches at a depth of 1050 feet borewell. A further depth of 75 feet was dug, so the total depth of borewell is at 1050 feet. I am planning for agricultural work in this 3 acres piece of land. Considering the amo...
    Anonymous (not verified)posted 4 months 1 week agoread more
  • While enhanced irrigation coverage has been hailed as an important way to improve agricultural productivity, it continues to lag behind in India and agriculture continues to be rainfed, subject to the vagaries of the monsoon. High groundwater dependence for irrigation has not only led to its depleti...
    aarti kelkar kh...posted 4 months 1 week agoread more
  • I have a borewell depth of 650 ft and I have fixed a 3hp 40 stage single phase Texmo pump, because of the silt the pump run only once and its not running now. What should I do now to pump the water. Is there any way to use the same pump by doing any process or should I go for compressor pump. If yes...
    Anonymous (not verified)posted 4 months 1 week agoread more
  • Government identifies 100 wetlands for restoration in next five years At the 14th session of the Conference of Parties (COP 14) to the United Nations Convention to Combat Desertification (UNCCD), the Environment Ministry identified more than 100 wetlands for restoration in the next five years&...
    swatiposted 4 months 1 week agoread more
  • Sardar Sarovar dam fills up while ignoring thousands in submergence area As the rains arrived this year, the central government decided to fill up the Sardar Sarovar dam to its full height of 139 m for the first time since its construction was completed in 2017. The government has claimed since 201...
    swatiposted 4 months 1 week agoread more
  • Is the water received from Chennai Metro Water safe for consumption ? Or do we need RO purifier for it for safety?
    Anonymous (not verified)posted 4 months 1 week agoread more
  • Does borewell recharge requires removal of submersible pump? 
    Anonymous (not verified)posted 4 months 2 weeks agoread more
  • While most parts of the country are facing a water crisis, here’s a case from the arid state of Rajasthan, where decentralized initiatives are solving water issues. Dungarpur in southern Rajasthan has exemplified how community participation with local level planning processes are working towards i...
    Anonymous (not verified)posted 4 months 2 weeks agoread more
  • We are Villa community with 180 villas and we already have water meters. We would like to know what are best strategies and possibilities of remote monitoring, etc. Please send me any information to this regard to my email kvelorum@gmail.com
    Anonymous (not verified)posted 4 months 2 weeks agoread more
  • How to lift broken motor from a borewell at 400ft depth?
    Anonymous (not verified)posted 4 months 2 weeks agoread more

Pages

Policy matters this week

NGT pushes MoEF to issue notification to ban unnecessary use of RO purifiers

Topics

Sub-Categories

Regions

News this week

Cyclone Bulbul causes devastation in West Bengal and Odisha

Topics

Sub-Categories

Regions

Study points to vulnerabilities faced by women in the mountains and plains of Uttarakhand, which is likely to only increase with climate change.

Socially constructed notions of the different roles and responsibilities of men and women have a huge bearing on access to and control over resources, and subsequently on their vulnerabilities. More often than not, this leads to vulnerabilities that are skewed towards women, more than men. Gender mainstreaming entails re-organising formal structures of decision making and institutional processes to acknowledge gender as a centrality, rather than as an add-on.

Topics

Sub-Categories

Regions

Sir,

I need help for setting up subsidised solar irrigation pump. What are the requirements for the process? Where should I contact and whom?

Topics

Sub-Categories

Regions

Hello,

Pls advice me a permanent solution for my septic soak pit overflowing issues. We have a total 6 members family (adult-4 children-2) and our home is an independent one. I cleaned up my septic tank after 15 years but problem is not with the septic tank but the soakpit. I consulted with many people, each one suggests different things. Kindly advise me.

Thank you
Jaison, Kerala

Topics

Sub-Categories

Regions

November 8, 2019 12:00AM

Topics

Sub-Categories

Regions

The number of people vulnerable to floods triggered by climate change by 2050 is triple that of previous estimates, according to a new study.

A new research study by Climate Central, a US-based non-profit research group has projected that 300 million people could face annual coastal flooding triggered by climate change by 2050. Scott A Kulp and Benjamin H Strauss, the authors of the study suggest that the choices made today will likely determine whether our planet’s coastlines will even be recognizable, by the middle of the twenty first century.

Topics

Sub-Categories

Regions

Policy matters this week

Focus on water conservation in MGNREGA: Rural Development ministry to states

Topics

Sub-Categories

Regions

News this week

The link between water and Delhi's air pollution crisis

Topics

Sub-Categories

Regions

I have a pond in Murthal, Sonipat district and my borewell water parameters shows 1530 ppm of TDS and 6.2 - pH. I want to reduce the TDS level upto 500 - 700 ppm for fish farming and pearl farming. The TDS level of water in this area has increased significantly in the past few years and I am looking for a solution to counter this situation. Also need suggestion, if this water treatment affects the growth of live stocks in any way. Appreciate for the suggestions and solutions.

Topics

Sub-Categories

Regions

Pages

Subscribe to RSS - Technology