Treatment Of Wastewater From Agricultural In India
Written By:– Hrishika Rawat
Security of water, food, and energy are becoming increasingly crucial and vital for India and the rest of the globe. The combined impacts of agricultural expansion, industrialization, and urbanization are causing most river basins in India and worldwide to shut or close, resulting in moderate to severe water shortages. Water usage efficiency and demand management might help meet current and future freshwater demands.
As a result, following necessary treatment, wastewater/low-quality water is emerging as a viable source for demand control. In India’s main cities, an estimated 38354 million litres per day (MLD) of sewage is created, while the sewage treatment capacity is only 11786 MLD.
Similarly, just 60% of industrial wastewater is treated, primarily in large-scale businesses. State-owned sewage treatment plants, which handle municipal wastewater, and common effluent treatment plants, which treat wastewater from small-scale enterprises, are also not performing up to expectations. As a consequence, effluent from treatment plants is frequently unfit for human consumption, and wastewater reuse is mainly limited to agricultural and industrial uses.
Female and male agricultural labourers benefit greatly from wastewater-irrigated fields since they may produce crops, vegetables, flowers, and fodders that can be sold in neighbouring markets or used by their animals. However, there are more risks to human health and the environment when wastewater is used in agriculture, particularly in poor nations where wastewater is rarely treated and huge quantities of untreated wastewater are utilized in agriculture.
Using wastewater to grow crops can address water scarcity in agriculture
Water shortage in agriculture can be alleviated by judicious use of wastewater to produce crops. Farmers may utilize wastewater either directly through irrigation or indirectly by replenishing aquifers at a time when we need to produce more food to feed an ever-increasing population.
Using wastewater in the backdrop of water scarcity due to climate change formed the basis of talks in Berlin during the annual Global Forum for Food and Agriculture.
“…globally, only a small proportion of treated wastewater is being used for agriculture, most of it municipal wastewater. But (an) increasing numbers of countries—Egypt, Jordan, Mexico, Spain, and the United States, for example—have been exploring the possibilities as they wrestle with mounting water scarcity,” says Marlos De Souza, a senior officer with the Food and Agriculture Organization’s (FAO) land and water division.
Wastewater treatment
There are 234 sewage water treatment plants in India (STPs). The majority of them were built under various river action plans (from 1978 to 1979) and are located in (about 5% of) cities/towns along major river banks (CPCB, 2005a). The oxidation pond or activated sludge process is the most widely used technology in class-I cities, accounting for 59.5 per cent of total installed capacity. Up-flow Anaerobic Sludge Blanket technology follows, accounting for 26% of total installed capacity. Although the aggregate capacity of the plants is only 5.6 per cent, Series of Waste Stabilization Ponds technology is used in 28 per cent of them. In poor nations, where land is typically available at a fair opportunity cost and trained labour is in limited supply, a recent World Bank report highly endorsed stabilization ponds as the best wastewater treatment technology.
Status and need for the knowledge and skills on the safe use of wastewater
Wastewater is more saline owing to dissolved particles from metropolitan areas, and it is concentrated even more in dry and tropical regions due to increased evaporation. Heavy wastewater usage in agriculture can lead to salinity issues and lower land yield. Excessive industrial discharge into the environment can result in an accumulation of hazardous chemicals, which can stimulate the growth of weeds, algae, and cyanobacteria, causing groundwater and downstream water quality to degrade.
Because wastewater is a major source of plant nutrients, soils irrigated with wastewater are nutrient-rich. As a result, fertilizer dosages should be adjusted based on the nutrients in wastewater, the volume of wastewater to be applied, and the crop nutrient requirements. Soil testing should be done on a regular basis to check for nutritional imbalances or soil illness.
Crop tolerance to heavy metal concentrations in the soil varies. Metal affinities and the accumulation of absorbed heavy metals in various plant sections also vary. As a result, crops should be chosen in such a way that they can withstand the harmful elements of wastewater and accumulate in plant parts that aren’t consumed.
A suitable combination of timber trees, fruit trees, fodder, industrial crops, and cereals should be created depending on the quantity and quality of wastewater available for usage. It is recommended that wastewater be used on public parks, golf courses, green belts, and tree plantations.
Farmers should be made aware to use fresh water for washing the produce before taking it to the market. Consumers should also resort to sufficient washing and cooking to reduce pathogen load. Regular health checks and administration of anthelmintic drugs and awareness campaigns should be carried to educate the farmers, consumers, and policymakers about wastewater issues and impacts.
Indigenous technical knowledge (ITK), local knowledge’’ and “Traditional Knowledge should also be properly documented for safe and sustainable wastewater use.
Conclusion
The absence of treatment in underdeveloped nations such as India causes issues with wastewater reuse. The goal is to discover low-cost, low-tech, user-friendly technologies that, on the one hand, do not jeopardize our significant wastewater-dependent livelihoods while also protecting our important natural resources. Constructed wetlands are now being acknowledged as an effective wastewater treatment method.
Constructed wetlands use less material and energy than traditional treatment systems, are simple to run, have no sludge disposal issues, and can be maintained by unskilled staff. Further, these systems have lower construction, maintenance, and operation costs as these are driven by natural energies of sun, wind, soil, microorganisms, plants, and animals.
Hence, Policy decisions and coherent programs encompassing low-cost decentralized wastewater treatment technologies, bio-filters, efficient microbial strains, organic/inorganic amendments, appropriate crops/cropping systems, cultivation of remunerative non-edible crops, and modern sewage water application method appear to be required for planned, strategic, safe, and sustainable wastewater use.
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