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Vol. 16 No. 3 - July 2010

The Ganga: A Polluted Purifier

 By: 1Deepika Sharma and 2U.N. Rai*

Ganga: Mystical Powers of the Ganga

Ganga has always been more than an ordinary river. For millions of Indians she is a goddess. Yet the river is exploited as much as she is worshipped.

Ganga is in danger of dying - but if the river dies, will the goddess die too?

The question took Julian on an extraordinary journey from the Himalayas to the Bay of Bengal.

The Ganga River (Ganga in Indian language, Ganges is Latin form) is the largest and very important river basin of country. It has been a symbol of purity, but today it is grossly polluted. It has long history of reverence in India and it is often called Holy Ganga. It originated from Bhagirathi from the Gangotri Glacier in the Uttaranchal. The total length of river is about 2,510 km. One of the largest group of human population belts on earth is built around the Ganga.

The basin drains eight states, H.P., Punjab, Haryana, U.P., Rajasthan, M.P., Bihar, West Bengal and Delhi.

It is in flood throughout the summer months when the snow on the Himalayas melt. Since it is a fast-flowing, it's water is always muddy.

The Ganga River has been considered as the most sacred river of India in Puranas. It is called as Ganga Maa (or mother Ganga) or Ganga ji (or reverend Ganga). People of India believe that a bath in the holy waters of Ganga washes all the past sins of a person. Numerous pilgrimage centres such as Allahabad, Rishikesh, Haridwar, Varanasi and Patna are present all along the river. Water from the Ganga is used to cleanse any place or object for ritual purposes. The word Ganga is considered as a synonym of pure and holy water. According to a mythological legend, Lord Brahma collected the sweat of Lord Vishnu’s feet and created Ganga. Being touched by two members of the Trimurti (Brahma, Vishnu and Mahesh), Ganga became very holy.

Highly productive irrigated agriculture is practiced in fertile soils of Ganga basin since time immemorial and recent rapid industrialization has generated large demands for water and hydropower. The domestic water demand in high-population density urban areas scattered throughout the Ganga basin has outstripped the supplies.

Although there is a vast canal network in Upper Ganga basin, there are no large existing reservoirs except on Ramganga. After the Tehri dam is completed in near future, Ganga River will be partly regulated. Tehri will also help in irrigating new areas of about 3 lakh ha besides stabilizing the existing system. Tehri will also supplement water supply to Delhi through the Upper Ganga Canal.

In the hilly reaches up to Rishikesh, Ganga water is quite clean except for sediments. From Rishikesh onwards, disposal of sewage into Ganga begins. Besides the municipal waste of Rishikesh and Haridwar, industrial units discharge partly treated effluents into the river. Haridwar City has a population of 1.5 lakh and nearly 60,000 people visit the city every day on an average. This number rises to a few lakh on important religious days and may go up to 15 lakh on the auspicious days during Kumbha Mela. Considerable lengths of sewer lines are clogged by silts that flow in from the adjoining hills. Further downstream from Haridwar, Ganga flows through Bijnor, Garhmukteshwar, Narora and Kannauj. Here, water is not much polluted as these towns do not have any large industry. Moving downstream, the situation changes for the worse at Kanpur from the quality point of view. Sewage from the city (population 2.7 million) coupled with untreated toxic waste discharge from about 150 industrial units results in severe damage to water quality.

The mean value of DO at 3 mg/l at Jajmau, near Kanpur, reflects the levels of pollution caused by discharge from 80 tanneries and other industries. At Allahabad with population of more than a million, municipal wastes are the major contributor to river pollution. Yamuna whose water is highly polluted joins Ganga at Sangam. Large volume of municipal and industrial waste is dumped in the river at Varanasi, a city with approximately 1.2 million population. The Varuna River, which joins the Ganga in the vicinity of Varanasi, receives waste from many drains. Besides, due to the religious belief that those who die in Varanasi are sure to go to heaven, on average, more than 40,000 dead bodies are cremated on the river bank and the ashes and remains are dumped in the river.

Entering Bihar, a number of industries (including fertilizer and oil refining) have come up along Ganga River. Patna is the most populous city whose wastes are dumped in the river. At Kolkota in West Bengal, the Hooghly (Ganga) river basin is highly populated as the wastes from numerous industries as well as municipal sewage is dumped in the river.

In view of the magnitude of water quality problems in the Ganga basin, two action plans were launched by the government of India: the Ganga action plan and the Yamuna action plan.

Ganga Pollution: An Ever-increasing Problem:

The level of pollution in the Ganga river has reached an alarming proportions. Two types of point sources like, surface drains carrying municipal sewage or industrial effluents, pumping stations and sewage systems effluents from industries etc are found. These point sources can be measured. Second is non point sources which cannot be measured such as run-off from agricultural fields carrying chemicals and fertilizers, run-off from areas used for dumping of solid waste and open defecation, dumping of unburn/ half burnt dead bodies and animal carcasses, dhobi ghats, cattle wallowing, mass bathing, floral offerings etc. According to a study nearly 89 milion litres of sewage is desposed into Ganga from the 12 municipal towns that fall along its route till Haridwar, where the amount of the sewage disposed in the river increase during the Char Dham Yatra season when nearly 15 lacs pilgrims visit the state each year. Apart from sewage disposal of half burnt human body at Haridwar and hazardous medical waste from the base hospital at Srinagar due to absence of incinerator are also adding to the level of Ganga pollution. The major polluting source of Ganga is leather industries, especially near Kanpur which release large amount of Chromium and other chemicals and heavy metals.

An emblem of India’s rich culture and ecology, the Ganga is, unarguably one of the World’s major river but the river is exploited and the result severe threat to the river ecology, water security and thereby to the lives of millions who are dependent on it. In Ganga there are three type of pollutants silt, biological and chemical. Sedimentation may be reduced by rehabilitation of catchment area through tree plantation.

It is estimated that some 900 million litres of sewage is dumped into the Ganga every day; three-fourths of the pollution in the Ganga is from untreated municipal sewage. In particular the middle reach of the basin between Kanpur and Buxar is the most urbanized and industrialized, as also the most polluted segment of the basin. Municipal and industrial wastes with dangerous concentration find entry into the watercourse in this segment and pose a grave threat to society.

However, industry is not the only source of pollution. An estimated 2,000,000 peoples ritually bath daily in the river, which is considered holy by Hindus.

Ganga Action plan: Where we stand now?

Ganga runs its course of over 2500 kms from Gangotri in the Himalayas to Ganga Sagar in the Bay of Bengal. Department of Environment, in December 1984, prepared an action plan for reduction of pollution load on the river Ganga. The Cabinet approved the GAP (Ganga Action Plan) in April 1985 as a 100 per cent centrally sponsored scheme.

Under Ganga action plan Government of India constituted the CGA (Central Ganga Authority) in February 1985 and renamed it as the NRCA (National River Conservation Authority) in September 1995, under the chairmanship of the Prime Minister. The GAP-I envisaged to intercept, divert and treat 882 mld (Million litres per day) out of 1340 mld of wastewater, generated in 25 towns in 3 States of Uttar Pradesh, Bihar and West Bengal. The NRCD had scheduled the GAP-I for completion by March 1990, but extended it progressively up to March 2000. The GAP-I was still in progress, the CGA decided in February 1991 to take up the GAP-II.

Many operation have taken up in Ganga Action Plan like, Increase high capacity sewage treatment plant. The NRCD sanctioned 16 STPs of 433.31 mld capacity under GAP II IN June 1994-99 but those sanctions also left about ¾ of the sewage uncovered.

How it can be saved ?

Due to continuous pollution of Ganga, threat is not only to humans, but also to several other species living there. The river is home to more than 140 fish species, 90 amphibian species and the endangered dolphin. We can save Maa Ganga by taking some prompt action. These are as follow:

Awareness among peoples of Rural Area.

Until now Ganga was able to clean itself and maintain the rate of pollution because of the presence of certain bacteria’s and plants but now because of the high value of the contaminants, those plants are also dying. So ultimately we are not only polluting the river but also destroying the bacteria which are helping in controlling the pollution.

Time has come when efforts should be made to create awareness among masses. So that we can help the government in controlling the increasing pollution.

Increase the capacity of sewage treatment plant.

Sewage treatment, or domestic wastewater treatment, is the process of removing contaminants from wastewater and household sewage, both runoff (effluents) and domestic. It includes physical, chemical, and biological processes to remove these contaminants. Its objective is to produce a waste stream (or treated effluent) and a solid waste or sludge suitable for discharge or reuse back into the environment.

Sewage is created by residential, institutional, and commercial and industrial establishments and includes household waste liquid from toilets, baths, showers, kitchens, sinks etc. that is disposed of via sewers. In many areas, sewage also includes liquid waste from industry and commerce.

The separation and draining of household waste into grey water and black water is becoming more common in the developed world, with grey water being permitted to be used for watering plants or recycled for flushing toilets. Most sewage also includes some surface water from roofs or hard-standing areas and may include storm water runoff.

Sewerage systems capable of handling storm water are known as combined systems or combined sewers. Such systems are usually avoided since they complicate and thereby reduce the efficiency of sewage treatment plants owing to their seasonality. The variability in flow also leads to often larger than necessary, and subsequently more expensive, treatment facilities. In addition, heavy storms that contribute more flows than the treatment plant can handle may overwhelm the sewage treatment system, causing a spill or overflow.

As rainfall travels over roofs and the ground, it may pick up various contaminants including soil particles and other sediment, heavy metals, organic compounds, animal waste, and oil and grease. Examples of treatment processes used for storm water include sedimentation basins, wetlands, buried concrete vaults with various kinds of filters, and vortex separators (to remove coarse solids). Separate sanitary sewers should not include any storm water. Sanitary sewers are much smaller than storm sewers, and they are not designed to transport storm water. In areas with basements, backups of raw sewage can occur if excessive storm water is allowed into a sanitary sewer system.

There is a need to develop a vegetation cover along the bank of river Ganga consisting of pollution resistant and abator having commercial and economic value for environmental management of pollution. The best green technology for remediate the Ganga pollution is development of constructed wetlands comprising of aquatic plants and algae for treatment of domestic waste and sewage emanating from major cities located along the bank of river.

Wetland: A Green Attempt

Wetlands are natural purifier of water and rich in productivity ecosystem, it provides food and clean water. Wetlands are home to some of the richest biodiversity on earth. Wetland have vast capacity to absorb chemicals filter pollutants sediments and cleanse life bearing water and capable of breaking down suspended solids and neutralizing harmful bacteria.

How Wetland Clean up Water?

A very important function of wetland is natural ability to filter the clean water. Water entering a wetland slows down as it moves through vegetation. Suspended particles begin to fall out or water settle into the soil at the bottom of a wetland or become trapped among the vegetation.

Wetland plants are able to take up waste water pollutant into their cells. The dead plants in the bottom of a wetland pond help and provide space and condition for important Microbes. microbes also attach themselves to stem of living plants.

Various process like decomposition, predation and neutralization, these microbes are able to transform contaminant into the less harmful forms. Microbes also convert various nitrogen compounds into nutrients that help plant grow.

Constructed wetland:

A constructed wetland is an artificial marsh or swamp, created for anthropogenic discharge such as waste water, storm water run-off or sewage treatment, and as a habitat for wild life, or for land reclamation after mining or other disturbance. Natural wetlands act as biofilter, removing sediments and pollutants such as heavy metals from the water, and constructed wetland can be designed to emulate these features. Constructed wetlands are built by humans. These constructed wetlands are primarily built to clean up waste water and create wild life habitat. Constructed wetlands naturally filter and treat waste water and are often less expensive than traditional treatment plants.

In an urban environment where land is scarce, a traditional treatment plant may produce more reclaimed water per acre but a wetland has numerous additional benefits. It provides valuable wild life habitat, supporting numerous species of birds, mammals, amphibians and reptiles. These wetlands also serve as a recreational and educational site for visitors and residents. Constructed wetland will have four parts-

  1. The linear system will keep the wastewater and ground water out of contact in the system and it will be made from 30 mil. Poly vinyl chloride (pvc) material.
  2. The distribution medium system at the inlet will usually be a coarse drain filed rock of ¾ to 2½ inches in diameter.
  3. Plant system growing in the wetland will be cattails, bulrushes, reeds, sedges and many other plants, which would grow and flourish in the system to operate at maximum efficiently and also useful for metal uptake.
  4. The under-drain system at the end of wetland will be slotted with pipe. The under-drain moves the treated waste water out of the wetland.

Constructed wetlands are of two types: subsurface and surface flow wetland .sub surface flow wetlands can be categorized as horizontal flow and vertical flow constructed wetlands. Subsurface-flow wetlands move effluent, agriculture run-off, tannery or meat processing wastes, waste water from sewage or storm drains through lavastone or sand medium on which plants are rooted. Surface flow wetlands move effluent above the soil in a planted marsh or swamp, and can be supported by a wider variety of soil types including bay mud and other silty clay. In subsurface-flow systems, the effluent may move either horizontally, parallel to the surface, vertically, from the planted layer down through the substrate and out. Subsurface-flow systems have advantage of requiring less land area for water treatment, but are not suitable for wildlife habitat as are surface-flow constructed wetlands. The community found in wetland is called periphyton. Different species of aquatic plants have different of heavy metal uptake, a consideration for plant selection in a constructed wetland used for water treatment.

In constructed wetland many plant species planting of reed beds are popular in European plants such as, cattails, Typha Species , Sedge, Water Hyacinth, Eicchornia crassipes and Pontederia.

Buckbeans, Menyanthes trifoliate and Pendant grass (Aretophila fulva) are also useful for metal uptake. Wetland muck soils support immense population of microorganisms. Some of these microbes can use pesticides and other organic molecules as food. Wetlands reduce some pathogenic bacteria after only two hours of contact with wetland plants.

Physical, chemical, and biological processes combine in wetlands to remove pollutants from waste water. Treatment of waste water within a constructed wetland occurs as it passes through the wetland medium and plant rhizosphere. A thin aerobic film around each root hair is aerobic due to the leakage of oxygen from the rhizomes, roots, and rootlets. Decomposition of organic matter is facilitated by aerobic and anaerobic micro-organism present. Microbial nitrification and subsequent denitrification release nitrogen as gas to the atmosphere. Phosphorous is co-precipitated with iron, Aluminium, and Calcium compound located in the root bed medium suspended solids are filtered out as they settle in the water in surface flow wetlands..Harmful bacteria and viruses reduced by filteration and adsorption by biofilms on the rock media in sub surface flow and vertical flow system.

National Botanical Research Institute (CSIR) has planned to treat municipal sewage waste water with aquatic plants before allowing them to flow into the river as a low cost, eco-friendly and sustainable solution. The project entitled “plant based management of Ganga water pollution” was sanctioned to the institute by the National River Conservation Directorate, Ministry of Environment and Forest, Govt. of India. Under this project scientists plan to cover river banks at different spots, from Gangotri in Uttrakhand to Ganga Sagar in West Bengal.

* International Society of Environmental Botanists, National Botanical Research Institute, Lucknow; E-mail: 1deepikadesire@yahoo.in; 2rai_un@rediffmail.com

This article has been reproduced from the archives of EnviroNews - Newsletter of ISEB India.

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