PREVIOUS STORIES, 20 March 2017 A story dedicated to the theme of World Water Day 2017

Problems of Wastewater: An Overview

Nandita Singh and Om Prakash Singh

 

 

When water is used for different purposes, be it domestic, industrial or agricultural, it often receives impurities that may be physical, chemical or biological, which adversely affect its quality, turning it into wastewater. According to estimates from the Central Pollution Control Board (CPCB), urban centres of India produce as much as 61,754 million liters per day (MLD) of municipal wastewater or sewage, which includes the wastewater from residences carrying bodily wastes (primarily feces and urine), washing and bathing water, food preparation wastes, laundry wastes, and other waste products of normal living as well as liquid-carried commercial wastes from stores and service establishments such as hotels, offices and hospitals having characteristics similar to household flows. Less than 40% of the urban sewage is treated, though inadequately, before being released into local water bodies. Regarding industrial wastewater, according to one estimate, the total generation in India is over 83,000 MLD. According to CPCB, the major contributing industries are distilleries, sugar, textile, mining, electroplating, pesticides, pharmaceuticals, pulp & paper mills, tanneries, dyes and dye intermediates, petro-chemicals, cement, steel plants etc. Industrial wastewater contains a variety of toxic chemicals. There exist no estimates of agricultural wastewater generated in the country, but it is known to contain chemicals from fertilizers and pesticides, which either drain into neighboring surface water bodies or leach into soil polluting the ground water. The problems posed by wastewater for ecosystems and human populations are intimidating. In an era where freshwater availability is already challenged by increasing population pressure and adverse climate change impacts, wastewater disposal further escalates the crisis by polluting available freshwater resources. This not only decreases freshwater availability for human and ecological uses, but thwarts enjoyment of human rights to water, health, culture, livelihood and others, and on the whole challenges sustainable development in various ways. The title photo depicts Bellandur, one of the largest lakes in Bengaluru, Karnataka, which used to serve as the drinking water source for 18 villages until 1970s but is today a wastewater body that receives sewage and industrial effluents from the city. The water is dark and opaque, covered with weeds at places and produces a strong foul stench that engulfs the entire neighborhood. At the outlets downstream of the lake, heavy foaming is visible, and wildlife and fish can no longer thrive.

 

 

Untreated sewage being disposed into river Ganga through the Sisamau drain in Kanpur, Uttar Pradesh

 

Dumping of untreated sewage directly into rivers and lakes is a widespread problem in India. The 2,525km-long Ganga river winds through Uttarakhand, Uttar Pradesh, Bihar, Jharkhand and West Bengal. The river has various places of religious and industrial importance along its banks, besides providing the most fertile river basin for agriculture, with a dependent population of over 400 million. According to CPCB’s 2013 report, 2,723 MLD of untreated sewage is discharged by various cities located along this river, making it world's fifth most polluted river. Kanpur generates over 435 MLD sewage, major part of which is dumped directly into the river through a dozen of drains. Sisamau drain is the dirtiest open drain of Kanpur that discharges the highest amount of untreated sewage (upto 150 MLD) into the river at a spot which is next to the Power House that pumps drinking water supply for the city. The wastewater carried by the Sisamau drain is highly polluted – fields irrigated by its water become unproductive and local fish populations in the Ganges have died except one hybrid variety of Tilapia. People living in the vicinity of the drain complain of skin and stomach problems and a nostril-numbing stench emanates continuously. During monsoons, water from the drain enters their homes, further affecting their health and belongings. Ganga is the most holy river in India associated with several religious observances and festivals, such as Kumbh, Chath and Kartik Purnima when devotees take holy dip in the river. Pollution of the river at any location upstream disrupts observance of these religious occasions downstream, hindering enjoyment of people's cultural rights.

 

 

Tanned leather pieces being dried in the open in one of the tanneries in Kanpur, Uttar Pradesh

 

Kanpur is the largest producer of leather and leather goods in the world, bringing foreign exchange worth Rs 60,000 million (>918 million USD) to the country and giving direct livelihood to >100,000 people. Jajmau, an industrial suburb in Kanpur, has some of the biggest leather tanneries in the country, though there are also several small-scale industries in the sector. On the whole, the city is home to over 400 tanneries. Tanning is the most important process in leather production that transforms the raw hide into usable leather that remains flexible in heat and does not putrefy when wetted. While a number of different tanning methods are available, chrome tanning - regarded as the most efficient and effective method but a highly polluting process - is widely used in Kanpur.

 

 

Wajidpur drain disposes about 15 MLD of untreated tannery effluent along with inseparable sewage into river Ganga in Kanpur, Uttar Pradesh

 

The tanneries located in Jajmau area of Kanpur use many toxic chemicals, and leather processing here generates about 50 MLD effluents. According to a very recent government report, only 4-5 MLD effluents is pumped for treatment, while the surplus is discharged directly into river Ganga through Wajidpur drain. Studies show that the concentration of heavy and transition metals in this wastewater is extremely high. The drain water appears bluish due to presence of high concentrations of chromium used in the tanning process. In the wastewater that undergoes treatment at the common effluent treatment plant (CETP) in the area, levels of magnesium, phosphate, nitrate, fluoride, phenol, oil and grease have been found to be above permissible limits. Other heavy metals such as arsenic, cobalt, iron, copper, manganese, zinc, lead, cadmium and nickel are also present in significant quantities. The various heavy metals in the treated and untreated wastewater have contaminated groundwater which is utilized as a drinking water resource and are having a devastating impact on environment and public health. Aquatic life in the river is threatened (fish kills are often reported) and the river water quality is degraded. The treated wastewater is supplied for irrigation of farmlands in the Jajmau region which has furthered contamination of food chains; reduced crop productivity, bringing greater public health risks. Cadmium is a potent kidney toxicant while chromium VI is a known human carcinogen. Other metals too are potent sources of renal, neurological, skin diseases and blue baby syndrome.

 

 

'Gas Pani' or wastewater containing acid mine drainage from an underground coalmine in Tipong Colliery of Makum Coalfield being released directly into Tipong river in Tinsukhia district, Assam

 

Wastewater from mines may contain a number of harmful chemical contaminants. The tertiary coal deposits in northeastern part of India are highly enriched with sulphur, and therefore well known for the generation of acid mine drainage (AMD) which pollutes water. At Tipong colliery, mine water is regularly discharged in order to enable the mining process. This discharge contains AMD due of oxidation of sulphide minerals (mainly pyrites) to form sulphuric acid through increased exposure to water and air. Formation of AMD further triggers reactions that help release iron, aluminum, manganese, nickel, lead and cadmium, as well as chromium, copper, zinc and cobalt, though in smaller quantities. The orange color of the mine water discharge seen in the photo is caused by ferric hydroxide precipitating out of the water which, depending on the conditions, may form inside the mine or later. AMD in mine wastewater is also a problem associated with mining of copper, gold, silver, zinc, lead, and uranium.

 

 

Tipong river polluted by acid mine drainage near Tipong Colliery of Makum Coalfield in Tinsukhia district, Assam

 

Acid mine drainage (AMD) is a byproduct of the mining industry which may end up severely polluting surface as well as groundwater resources in and around both active and abandoned mines. Bright orange or reddish color of the water and stained rocks are usually tell-tale signs of AMD. Studies in Tipong and other collieries of the Makum Coalfield show that ground water close to the collieries and AMD affected streams are highly contaminated. Polluted surface water bodies do not support aquatic life, killing fish and other flora and fauna, and make it unfit for drinking. Attacks of gastroenteritis due to high iron and sulphur contents are common, as are cases of skin infections and ulcers among local inhabitants. It destroys soil fertility in paddy fields due to the acidic nature, and reduces natural vegetation diversity. The color further makes it unsuitable for recreational purposes. At Tipong colliery, the quantum of mine water discharge is large, continuing for upto-two hours at a stretch 4 times a day. During the rainy season, the discharge continues throughout the day because of seepage of rainwater into the mine. Though a treatment plant exists at the colliery, its capacity is too small to handle the discharge, thereby causing severe pollution of Tipong river.

 

 

Wastewater from a textile dyeing industry being discharged untreated into a stormwater drain for disposal into river Yamuna in South-East district, National Capital Territory of Delhi

 

National Capital Territory of Delhi (NCTD) is estimated to be home to about 130,000 industrial units, distributed between 28 industrial clusters and residential areas. These include many textile dyeing units which present a huge pollution problem through generation of millions of liters of hazardous toxic wastewater, full of color and organic chemicals. Many of the chemicals are poisonous and damaging to human health directly or indirectly. Presence of sulphur, naphthol, vat dyes, nitrates, acetic acid, soaps, chromium compounds and heavy metals like copper, arsenic, lead, cadmium, mercury, nickel, and cobalt and certain auxiliary chemicals all collectively make the effluent highly toxic. The colloidal matter present along with colors and oily scum increases the turbidity and gives the water a bad appearance and foul smell. In many cases, the wastewater from the dyeing industry in NCTD is released untreated into drains that finally discharge into the Yamuna river, contributing to its progressive ‘death’. Presence of the untreated wastewater in the river prevents the penetration of sunlight, in turn depleting dissolved oxygen in water. This destroys marine life and also hinders self-purification process of the water. The effluent further contaminates aquifers in the vicinity, making groundwater unfit for human consumption. In addition when this effluent is allowed to flow in the fields it reduces soil productivity, besides entering the food chain.

 

 

Stretch of river Yamuna polluted with untreated industrial wastewater in South-East district, National Capital Territory of Delhi

 

Many of the 130,000 industrial units in the NCTD produce toxic wastewater, a substantial amount of which is directly released untreated into river Yamuna. The extent of toxic wastes in the river water, mostly originating from industrial sources, is testified by the thick white foam overlaying the water surface. CPCB which monitors the water quality of Yamuna in NCTD has graded it in the severely polluted category, fit only for recreation, aesthetics, and industrial cooling. Severe pollution of the river water not only causes health hazards if used for drinking or bathing purposes, but the pollutants leach into the adjoining aquifers, making the groundwater unfit for drinking. Vegetables and crops raised with the polluted water pose further health risks not only for the local population, but also for customers outside. In fact, use of this frothing river for recreation is questionable as is its use for religious purposes, especially on occasions such as Chath or Kartik Purnima when devotees may be intimidated of entering the chemically laden waters for a holy dip.

 

 

Avalahalli Lake highly polluted by untreated industrial wastewater from manufacturing industries on its banks in Bengaluru, Karnataka

 

A great majority of Bengaluru’s lakes and tanks have become recipients of untreated industrial effluents and sewage. Pharmaceutical and other manufacturing industrial units situated along its banks lack adequate and operational treatment facilities on site, leading to release of untreated industrial wastewater into the lake. Increasing concentrations of the contaminants in the lake causes pollution of the groundwater resources on which local inhabitants may depend for drinking and other domestic uses. Pollution of the lake also disturbs the natural aquatic flora and fauna, hence affecting the local ecology.

 

 

Houseboats - a major source of untreated sewage in Punnamada Lake in Alappuzha district, Kerala

 

Tourism in Kerala is a major economic activity that provides employment for nearly 1 million people in the state. Houseboat tourism in Vembanad Lake, the longest lake of India lying across 3 districts of Kerala, is one of the main tourist attractions. Most tourists visit Punnamada Lake which is the part of Vembanad Lake lying within Alappuzha and Kottayam districts, the main attraction being houseboat tourism. There are over 1000 houseboats in Punnamada, of which only about 500 are registered. Data from the Kerala State Pollution Control Board show that Punnamada and the larger Vembanad Lake are under severe environmental stress due to biological, chemical and physical pollutants. The rapidly growing houseboat tourism is a major culprit behind the increasing pollution. A substantial part of these pollutants is derived from the sewage released from the houseboats, besides other wastes. The average of total coliform bacteria has been found to be about 30% higher near the houseboat jetty than in the rest of the lake. Eutrophication is a serious problem due to pollution – a vicious cycle of de-oxygenation that affects the fish and other aquatic organisms. Also, degradation of quality in the drinking water sources in the neighboring villages is a major consequence, sometimes leading to outbreaks of gastrointestinal infections.

 

 

Wastewater from shipping industry destroying ecosystem near Krishnapatnam Port in Nellore district, Andhra Pradesh

 

Krishnapatnam Port is India's largest private sector port that has been operational since 2008. It covers an area of 4,553 acres and is expected to handle 200 million tonnes of cargo annually. While it would definitely help boost the country’s economy, the impact of wastewater emanating from activities at the port is turning out to be considerable. Due to leakage of oil and release of untreated wastewater from the ships into the deep backwater channel that provides the connectivity, the ecology of the entire area has been destroyed. The grasslands and natural vegetation on the banks has burnt out and fish populations in the channel wiped out. This has further destroyed the livelihoods of the local fishermen, besides also contaminating their drinking water options, in turn bringing ill-health and enhancing their economic plight.

 

 

A local drain carrying untreated wastewater from a dairy farm into Najafgarh drain, finally emptying into river Yamuna in South-West district, National Capital Territory of Delhi

 

In urban Delhi, dairy farming is a significant livelihood activity, especially in the urban villages. Some of the dairy farms are large with 40-50 buffaloes. The wastewater from dairy farms, which largely derives from animal waste and their washing, is almost never subject to any treatment, and is an important source of pollution of river Yamuna. It is rich in nutrients like nitrogen and phosphorous, which can cause eutrophication. It can also leach down to groundwater, polluting the local drinking water sources, affecting human health.

 

 

Najafgarh drain carrying sewage water for emptying into river Yamuna near Wazirabad Bridge, Central district, National Capital Territory of Delhi

 

The Najafgarh drain is a channelized waterway that was meant to transfer the water from River Sahibi that flowed from Rajasthan into River Yamuna, in order to prevent flooding during monsoon season. However, today it is the most polluted water body in the NCTD due to direct inflow of untreated sewage from surrounding populated areas which is discharged into Yamuna. In fact, Delhi had a network of several stormwater drains, big and small, originating mainly from the Ridge and feeding the Yamuna. Over time many of these have been turned into sewage drains, killing river Yamuna bit by bit. Presently 21 drains regularly discharge sewage from different parts of the NCTD into the Yamuna every day, of which 67 % pollution is caused by the Najafgarh drain alone.

 

 

Yamuna –a dead river – in Central district, National Capital Territory of Delhi

 

The stretch of the Yamuna that flows through Delhi traverses a distance of only 22 km but in the process, it becomes ecologically dead due to pollution from several million liters of untreated city sewage and industrial wastewater. The present state of the Yamuna river is alarming. Described now as a huge sewage canal, Yamuna water is almost unfit for human or even ecological use. It cannot even support bacteria or aquatic life. While the coliform bacteria count reaches up to 7,500 per 100cc of water, concentration of heavy metals such as cadmium, nickel, zinc, iron, copper, manganese, lead, chromium, mercury and arsenic in the river water and in the soil of nearby agricultural fields are also considerable along its course. The water appears black, and cannot sustain life. A report submitted by CPCB to the Supreme Court in 2015 reveals near negligible traces of dissolved oxygen (DO) in the waters of the river passing through NCTD, with a minimum DO level of 1 mg/l, while the minimum amount of DO that will support a large population of various fishes ranges from 4 to 5 mg/l.

 

 

A rural settlement on the bank of Vembanad Lake in Alappuzha district, Kerala

 

The Vembanad Lake is part of the larger Vembanad-Kol wetland, acknowledged as a wetland of international importance under the Ramsar Convention in 2002 and located partly below sea level. Shallow parts of the lake and its shores were converted into rice fields over the last century, with rural settlements developing alongside the fields on earthen bunds. These settlements are largely unconnected by land and lack access to basic amenities like water supply and sanitation. The houses have on-site sanitation facilities that drain their domestic wastewater directly into the lake, which implies increase in pollution load of the lake, particularly with increasing population. The practice of wastewater dumping directly into the lake has deepened water quality problem to the extent that at many locations, the residents no longer have access to safe water for drinking and other domestic uses, leading to health and concomitant economic concerns.

 

 

Spreading fertilizer in the paddy fields irrigated by Shanti Sagara in Devangere district, Karnataka

 

The practices followed in cultivation greatly affect the quality of water contained in surface water bodies as well as groundwater aquifers due to generation of wastewater from the fields. Intensive cultivation of crops causes release of chemicals from fertilizers and pesticides into the wastewater that may to seep down into the groundwater, leading to toxicity of the groundwater reserves that are often utilized for withdrawing drinking water. The agricultural runoff from the fields may also be allowed to be flushed into nearby surface water bodies with similar consequences for the local populations. The high nitrate and phosphorous content in such waters is often a result of consistent use of fertilizers while high concentration of persistent organic pollutants (POPs) like DDT, aldrin, dieldrin and heptachlor comes mainly from use of insecticides and pesticides. The latter cause cancer and other serious diseases, thus posing considerable health risk to affected populations. The agricultural fields shown in the photo are irrigated by Shanti Sagara (also known as Sulekere) which is the biggest tank in Karnataka and one of the largest in Asia, but they bring pollution to the tank through the agricultural runoff containing fertilizers and pesticides which is flushed back into it. It is noteworthy that water from Shanti Sagara is also supplied for drinking to the neighboring communities which, in the light of pollution from agricultural runoff, can pose health risk. Further, the use of polluted water for irrigation can introduce contaminants in the food chain.

 

 

A channel conveying untreated sewage into Moti Jheel in Motihari, Bihar

 

Moti Jheel is a picturesque natural lake in the midst of Motihari city. Spread over 450 acres in the midst of the town, the lake bifurcates the town in two parts. Once this lake was full of lotuses and a healthy green spot in the city. It was also once renowned for pisciculture, but is now hardly used for any practical purposes by the city dwellers. It has become the epitome of neglect with water hyacinth in stagnant polluted water. Pollution of the water is a result of release of untreated sewage straight into the lake through 20-30 small and big channels. A large number of new buildings that stand on encroached banks of the lake contribute further to the process by draining their sewage directly into the lake. Extreme pollution of this central surface water body in the city has not only led to environmental degradation, but also adversely affected the quality of the groundwater reserves which are widely used for drawing drinking water in the city.

 

 

Chamdawadi Nullah - a stormwater drain carrying untreated domestic wastewater in Mumbai, Maharashtra

 

Residents of Mumbai - the commercial capital of India - are expected to enjoy access to an efficient and effective wastewater disposal system. However according to one recent estimate, as much as 40% of the sewage generated in the city finds its way into the numerous drains and disposed into rivers, lakes or the sea completely untreated. Chamdawadi drain used to serve as a stormwater drain in Bandra area of the city which emptied stormwater into Mithi river. However, over the years, it has been turned into a wastewater drain into which untreated sewage and industrial wastewater is discharged along its course. The quantum of wastewater contained in the drain produces an unbearable nauseating stench, besides making it a breeding ground for flies and mosquitoes that bring different kinds of diseases to the local residents, particularly the slum dwellers nearby, adversely affecting their health and socio-economic wellbeing.

 

 

Chamdawadi drain filled with solid waste and untreated wastewater in Mumbai, Maharashtra

 

It is estimated that about 9,400 tonnes of municipal solid waste is generated in Mumbai each day. While some of this finds its way into the sanitary landfills, a good amount is just dumped into drains and other conveniently located surface water bodies. The plight of this drain which used to be a tributary of river Mithi, is more than obvious. Solid waste such as plastics dumped into water bodies further degrades water quality, introducing toxic chemical contaminants. If the water body is stagnant, these toxic chemicals may further leach down into the soil, further contaminating the groundwater, besides promoting breeding of flies and mosquitoes that bring disease and suffering to the local residents.

 

 

This story amply demonstrates how colossal a problem wastewater is and how devastating its impact can be for human and ecological systems, if not addressed appropriately and adequately. It leads to eutrophication of water bodies and can destroy ecosystems – both aquatic and terrestrial - leaving rivers, lakes and their flora and fauna ‘dead’ and forests and grasslands denuded. Foul stench and extreme pollution makes environments unfit for human residence, leading to ill-health and diseases. The untreated wastewater can even percolate underground and poison aquifers, restoration of the quality of which is difficult. Since underground aquifers are widely used in rural as well as urban India for drawing drinking water, poisoning of aquifers implies denial of the human right to water for the local residents. Pollution of surface water bodies with biological and chemical contaminants similarly makes rivers and lakes unusable for extracting drinking water. Even treatment of such extremely polluted waters may not render it potable. As the story shows, in many cases, the surface water bodies are so polluted that the water is not even fit for bathing or recreational purposes. Irrigation with such polluted water can introduce dangerous contaminants in the food chain, triggering serious health concerns. Also affected are the cultural practices in India where a large number of religious occasions like Kumbh and Chath are based on ritual bathing. Taking examples from the story, this is almost no longer possible in river Yamuna in Delhi and becoming increasingly challenging in river Ganga, which hurts religious sentiments of devotees. On the whole, it is evident that wastewater is a menace which can deeply affect sustainable development through multifarious pathways. It interferes with enjoyment of human right to water, food, health and several other concomitant rights of the people. Worst of all, it reduces the availability of freshwater for human and ecological uses by destroying clean water bodies. Such a damage has the potential to substantially deepen the water crisis in India in a climate change regime. There is thus an urgent need for the authorities to awaken to the cause and find sustainable ways to prevent or resolve the crisis caused by wastewater.

 

 

 

 

 

 

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Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh
Photo by: Om Prakash Singh