Wastewater treatment a must for food safety
Apr 25, 2022
Untreated industrial and sometimes domestic wastewater usually contains potentially toxic elements in concentrations that are several-fold higher than the maximum permissible limits for irrigation and drinking water. The authorities have so far failed to effectively enforce waste treatment laws, and strict adherence to the norms has remained a daunting task. Proper processing and management will improve food quality and safety as well as human and animal health.
Treatment of industrial wastewaters and sewage sludge is mandatory in India. Effluent treatment facilities for individual and clusters of industries are constructed in cities and towns for primary, secondary and tertiary treatment to remove toxic substances and kill pathogens. However, disposal of untreated industrial and urban wastewater into surface drains, underground water-recharging tube-bores, water bodies and for irrigation of field crops is common. Thus, toxic substances and perilous pathogens present in untreated effluents pose great health hazards to animals and humans through the soil/water-plant-animal-human continuum. The most important sources of water pollution with regard to human activities are urban and industrial wastewater.
Punjab Agricultural University (PAU) studies have shown the concentration of potentially toxic elements in wastewaters being several-fold higher for industrial cities (Ludhiana, Jalandhar and Amritsar) compared to less or non-industrial cities (Sangrur and Abohar). Further, sewage water from the domestic zone contained lesser toxic elements. In wastewater from electroplating industrial area, the Cr, Ni and CN concentrations were much higher than maximal tolerable limits for disposal on agricultural lands. Two case studies from Ludhiana’s open drain Buddha Nullah and Jalandhar are conspicuous. The Buddha Nullah carries nearly clean water before entering Ludhiana.
When travelling 15 km through the city, an increasing number of industries pour untreated wastewater that increases concentration of toxic metals manifold to make water almost like poison. The concentrations of Pb, Cr, Cd and Ni in wastewater at the city end, respectively, were 21, 133, 700, and 2,200 times higher than those in deep-tubewell water. Similarly, the concentration of Cr and Al in its water increased manifold after receiving the wastewater from the leather-manufacturing factories in Jalandhar city. Buddha Nullah, Kali Bein (historic rivulet turned into a sewer drain around Sultanpur Lodhi and Kapurthala) and several other drains eventually merge with Sutlej and Beas rivers, thus polluting their fresh waters, which are used for irrigation and drinking in Malwa region of Punjab, and Rajasthan.
Industries often drill deep tube-bores for disposal of their wastewater on or near their locations. Experts point out that this practice of so-called ‘charging ground aquifer’ actually pollutes the natural and clear water. One PAU study revealed that the concentrations of Pb, Cd, Ni and Cr were significantly higher in shallow hand-pumps’ water samples located within 200 metres of Buddha Nullah than deep-tubewell water, and were several-fold higher than the permissible drinking water standards. This is one of the main reasons for more and more groundwater becoming unfit for animal and human consumption, and in some cases for irrigation. A PAU investigation showed that bioavailable concentrations of Pb, Cd and Ni in surface soils, largely irrigated with sewage water, around densely industrialised area of Ludhiana were much greater than in the soils around a less industrialised city, Sangrur,
Adverse impact on crops
Growing vegetable and fodder crops using wastewater is a common practice near cities. These could cause toxicity in humans (consumption of vegetables) or animals (fodder) and subsequently in humans consuming milk, meat, etc. In a PAU study, the concentration of Cd in aboveground parts of maize, rapeseed (sarson & toria), pearl millet (bajra) and lady’s finger (bhindi) was 2-3.5 times higher when grown in polluted than non-polluted soils. The Ni concentration in various crops was 16% to 136% higher in wastewater-irrigated than tubewell-water irrigated crops.
Well-developed technologies are being used to treat wastewater for ensuring its good quality before use in several countries. In Europe and North America, water is generally pumped out from nearby water bodies (river, streams and lakes), cleaned and supplied to the cities and industries. Then, wastewater is treated before use for irrigation and excess is released to water bodies. But in India, open sewage-water drains pollute the shallow groundwater of hand-pumps and tube-wells installed in their vicinity.
Wastewaters of industries and cities must be efficiently treated, by considering both useful (nutritive and irrigation potential for crops) and harmful effects (toxic substances and pathogens) to meet requisite parameters, before they are discharged to drains or used for irrigation. Untreated industrial and sometimes domestic wastewater usually contains potentially toxic elements in concentrations several-fold higher than the maximum permissible limits for irrigation and drinking water. The authorities have so far failed to effectively enforce the waste treatment laws, and strict adherence to the norms has remained a daunting task.
Proper processing and management would lead to a win-win situation by upcycling and reusing of wastewaters and minimising environmental damages. It will also improve food quality and safety as well as human and animal health. Future food security, quality of food and feed, soils, animals and humans will depend on safeguarding our land, soil and water resources.
More News and Articles
May 28, 2022
With competition for water resources occurring in many regions of the world, how businesses meet their own needs and those of the communities in which they operate will be increasingly vital for their long-term survival and growth, says Erik Driessen, …
May 24, 2022
The Government has allocated $220 million under the Research, Innovation and Enterprise 2025 (RIE2025) Urban Solutions & Sustainability (USS) domain to drive new initiatives in water technologies and resource circularity. This draws from the National Research Fund, under the five-year …
May 23, 2022
The Pump Centre Conference offers a range of sessions headed by experts in their field. Here’s a precis of those talks made available so far, beginning with Smith & Loveless’ Andrew Hornabrook who considers the demands of optimising force main …
May 20, 2022
Since 1993, the United Nations has been calling for World Water Day. This year under the motto “Groundwater: Making the Invisible Visible”. Groundwater is invisible, but its impact is visible everywhere. Out of sight, under our feet, groundwater is a …
May 19, 2022
New Zealand's water sector must do more to attract a pipeline of talent in order to meet safe drinking water and improved environmental standards, a new report says.
May 18, 2022
The Water & Wastewater Equipment, Treatment and Transport (WWETT) Trade Show Successfully Wraps with Over 10,500 Registered Professionals in its Return to a Live Format Fueling Wastewater Industry Connection and Growth
WWETT, the world's largest annual trade show for wastewater and environmental service professionals, concluded its annual event February 21-24, at the Indiana Convention Center in Indianapolis.
May 17, 2022
Researchers decipher how the microbial inhabitants of sewage treatment plants help eliminate intestinal parasites.
May 16, 2022
Late in January the U.S. Environmental Protection Agency (EPA) and its federal partners announced the Industrial Control Systems Cybersecurity Initiative – Water and Wastewater Sector Action Plan to help protect water systems from cyberattacks. It focuses on high-impact activities that …
May 13, 2022
Boston Joins the ZutaCore Certified System Integration Partner Program, to Expand Availability of Intelligently Applied™ Direct-on-Chip, Waterless, Two-Phase Liquid Cooling
Global System Integrator Adds HyperCool™ to Enhance its Portfolio of Sustainable Data Center Solutions
May 12, 2022
Water and sewerage services provider Unitywater today announced it had appointed Anna Jackson its new Chief Executive Officer.
May 11, 2022
What is the best way to replace an old wastewater treatment plant? Which early warning system is most successful in protecting against flooding? Thanks to a method developed by Eawag, experts can analyse complex decision-making problems in a simple way.
May 10, 2022
Yarra Valley Water has completed a $34 million project to upgrade the sewer network to support Melbourne’s fast-growing northern suburbs. A proud adopter of trenchless technology, Yarra Valley Water has an emphasis on adding value while minimising disruption to the …