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From Stabilisation Ponds To Artifical Wetlands: 5 Wastewater Management Models Across The World For India To Follow

India generates an estimated 61,754 million litres of liquid waste per year, against a developed treatment capacity of 22,963 million litres, causing most on India’s untreated liquid waste to be directly discharged into water bodies

  • India will face an acute water crisis by 2030
  • Recycled wastewater can be used for irrigation and industries
  • Cost-effective recycling methods can be implemented across India

Demand for freshwater in India would rise to 1.5 billion cubic metres by 2030 from the current 898 billion cubic metres, as estimated by the Central Water Commission, a technical organisation under the Ministry of Water Resurces. This also means that the current shortfall between demand and supply of freshwater which is at 135 litres per capita is likely to rise to about 300 litres per capita in about a decade. In reality, India is heading towards a water crisis due to over exploitation of both freshwater and groundwater resources. This underlines the importance of conserving freshwater for only consumption and start using treated wastewater for irrigation, industries, energy production and other purposes. Several nations have successfully implemented wastewater treatment models to reduce the pressure on freshwater resources. India can take a cue from some of these examples and implement similar models to treat wastewater and put it to use instead of discharging it in to water bodies and polluting these.

Kenya – Development of Stabilisation Ponds

Stabilisation ponds in Kenya

Stabilisation ponds in Kenya

One of East Africa’s emerging nations in terms of economy, Kenya faced immense water scarcity from the 1980s to early 2000s. The emergence of private industries at the beginning of the 1980s resulted in the over utilisation of freshwater resources. The population boom and urbanisation in the 1980s also put immense pressure on the country’s water resources. Due to rapid consumption of freshwater, by 2006, nearly 18 million people in Kenya had no access to freshwater supplies and had to purchase water at exorbitant prices.

The government of Kenya emphasised on the development of low cost technologies which would not increase the state’s financial burden but prove to be effective nonetheless. The government developed a number of stabilisation ponds to treat wastewater throughout the country. Wastewater generated from household or industries is directly carried to a nearby stabilisation pond, where suspended solids in the water and soluble organic matter are removed using sunlight, algae and microorganisms. Pathogens in the wastewater are also removed. Once the wastewater has been treated, it is transported to industries or households for them to use it for purposes other than consumption. The Government of Kenya has set up more than 2,000 wastewater stabilisation ponds from 2006 to 2016. An investment of an estimated $600 is required to set up a wastewater stabilisation pond, which is way lesser than setting up a wastewater treatment plant. As per data from Water Mission International, Kenya’s wastewater treatment percentage has improved from 6 per cent in 1997 to 33 per cent in 2015, thus showing a gradual but healthy rate of growth and a potential model for India to follow.

Egypt – Treating Wastewater Using Kaolin

Water treated with kaolin was shown to be completely devoid of pollutants

Water treated with kaolin was shown to be completely devoid of pollutants

Egypt is another water scarce country with an available water supply of only 20 cubic metres per person as opposed to the minimum standard of 66 cubic metres. Similar to Kenya, rising population and economic development had resulted in over dependence on the river Nile for years. To treat wastewater, the government of Egypt decided to use kaolin, a silicate clay mineral known for its ability to absorb heavy metals found in industrial wastewater. Water treated with kaolin was shown to be completely devoid of pollutants and heavy minerals. In the ten years between 2005 to 2015, the Egyptian government set up 395 small scale wastewater management plants where kaolin treatment was effectively used. From a mere 8 million litres per day in 2005, Egypt’s wastewater treatment capacity rose to 27 million litres per day in 2015. According to United Nations Environment Programme, industrial dependency on river Nile has come down by 40 per cent in the last ten years, indicating that using kaolin can be effective for wastewater treatment. Kaolin is available in India as low cost mineral and can be effectively used in small scale wastewater management setups.

Vienna – Implementing Two-Sludge Activation Treatment for Large Cities

A two-sludge activation system was implemented in wastewater treatment plants around the city

A two-sludge activation system was implemented in wastewater treatment plants around the city

Vienna, Austria’s largest city generates 125,000 million litres of wastewater every day. Being a busy metropolis and an industrialised city, Vienna revamped its 27 sewage treatment plants to adequately handle wastewater for reuse. A two-sludge activation system was implemented in wastewater treatment plants around the city. Instead of a single sludge system which puts immense pressure on the waste treating tanks, the two-sludge system ensures carbon removal from wastewater and better nitrification for reuse purposes. Though this is not essentially a low-cost wastewater treatment model, revamping India’s wastewater treatment plants with two-sludge activation system would ensure that they become more capable at treating wastewater. The wastewater treated using a two-sludge system can be better utilised for irrigation purposes and hence will lessen much of India’s agricultural dependency on freshwater.

Nepal – Construction of Artificial Wetlands

Artificial wetlands use wetland plants such as duckweed, cinnamon fern and water nymph to remove waste and pollutants from water

Artificial wetlands use plants such as duckweed, cinnamon fern and water nymph to remove waste from water

Nepal has set an exemplary model in managing and treating wastewater. Industrialisation near the Bagmati river and the presence of only five wastewater treatment plants made wastewater treatment difficult to execute in Nepal by the late 1990s. Till 1997, the wastewater treatment plants in Nepal only had the capacity to deal with 5 per cent of the country’s wastewater. The Government of Nepal, in 1997 ordered the construction of an artificial wetland with plants which could treat wastewater and become a low-cost alternative to wastewater treatment plants. These wetlands use wetland plants such as duckweed, cinnamon fern and water nymph to remove waste and pollutants from water. More than 13 such artificial wetlands have been built across schools, hospitals and monasteries in the last 20 years. India can adopt this method of constructing wetlands for wastewater treatment as it costs Rs. 18 lakhs to build such a wetland but only Rs. 20,000 per year to maintain it.

Singapore – Turning Wastewater into Drinking Water

A wastewater treatment plant in Singapore

A wastewater treatment plant in Singapore

While many developed countries Spain, Norway and Sweden have extensive wastewater treatment systems in place, Singapore stands out among them. Reuse of wastewater in Singapore in not limited to just irrigation or industries but has been extended to consumption as well. 4 wastewater treatment plants in Singapore produce 430 million litres of water every day, all of which generates from wastewater. 5 per cent of the consumed water in Singapore comes from treated wastewater, thereby lessening the pressure on freshwater resources immensely. These plants extract pollutants, bacteria and viruses from wastewater and use reverse osmosis and membranes to refine the water to get rid of any disease causing elements. Singapore has also organised awareness campaigns on global freshwater scarcity and allows the public to tour these wastewater treatment plants so that the general public is also aware of how safe recycled wastewater is for consumption. India too should look at implementing a similar method to turn some of its wastewater into water fit for consumption.

The methods implemented by these countries show that there are several options which can be undertaken to treat wastewater in India. The cost effective methods can be undertaken in smaller towns and rural areas. The more costly methods, such as revamping of wastewater treatment plants need financial support and expertise from the government. Simultaneous implementation of both small and large scale methods will see wastewater treatment in India become a regular practice and decrease our dependency on freshwater resources.

Also Read: Wastewater Recycling: A Multi-Billion Dollar Opportunity For India To Avoid The Impending Water Crisis

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