Our ever-increasing demand for freshwater has led to a rapid decline in its sources, and scientists have attempted to find strategies to purify wastewater in order to reuse it to meet future demands. Today, the most common wastewater treatment techniques involve the use of chemicals or ultraviolet radiation to kill microorganisms or remove pollutants. But these classic techniques have several drawbacks, such as the toxic effects of chemicals on our health or the high energy requirements to operate treatment facilities. To create a sustainable wastewater treatment system, the focus has shifted to environmentally friendly and cost-effective technologies.
One of these technologies being explored involves using aquatic microorganisms, such as algae, which are known to be able to break down complex molecules. Recently, a team of Indian scientists (Algae and Bioenergy Research Laboratory, University of Uttaranchal; Faculty of Applied Sciences and Biotechnology, Shoolini University; and Department of Biotechnology, Dolphin Institute (PG) of Biomedical and Natural Sciences ), Korea (Department of Environmental Engineering, The University of Seoul) and Russia (Joint Institute for High Temperatures of the Russian Academy of Sciences and Department of Environmental Monitoring and Forecasting, RUDN University), led by Dr Pankaj Kumar Chauhan from Shoolini University, India, have developed wastewater treatment technology based on algal bioremediation. Their study is published in Total environmental science.
Algae quickly cover bodies of water with a green film or cause red tides, using nitrogen, carbon, phosphorus, or heavy metals in the water for nutrition. A high algal load in the water then creates competition for nutrients and sunlight with other microorganisms, resulting in a reduction in the number of bacteria present in the water. These are some of the properties that make algae promising wastewater purification agents. Added to this is the fact that they are environmentally friendly, self-contained and cost effective as a wastewater treatment agent.
Dr Chauhan explains the basis of the technology developed by his team: “We have selected a new strain of the microalgae Pseudochlorella pringsheimii because it can tolerate a high pollutant load and can develop over a wide range of temperatures. In addition, under stressful conditions, Pseudochlorella is known to accumulate large amounts of lipids in their cells, opening up the possibility of using this algal biomass for the synthesis of biofuels. ”
For their experiments, the researchers collected the strain of the microalgae Pseudochlorella pringsheimii in a natural pond and cultivated it in artificial reservoirs of raw urban wastewater that contained various heavy metal pollutants and antibiotic-resistant bacteria. After 14 days of culture, they measured three parameters in these ponds: water quality, growth and biochemical composition of P. pringsheimii. They also evaluated the possibility of using water treated with microalgae for fish farming.
The results of this pilot study were extremely encouraging. Growing P. pringsheimii dramatically improved water quality by removing heavy metals and harmful microorganisms. Dr Chauhan enthusiastically explains that “after the treatment, we observed that the levels of water pollution indicators such as chemical oxygen demand (COD), alkalinity and hardness respectively decreased by 83 , 2%, 66.7% and 69.6%. the growth of algae has almost naturally eliminated all of the bacteria and coliforms in the water. We also observed a significant increase in the lipid content of the algal biomass cultivated in the wastewater compared to the algae cultivated in the control medium. This means that these algae can be recycled for the synthesis of biofuels. ”.
Moreover, while no sucker fish survived in raw sewage, in treated sewage 84% of them not only survived but more than ten days, their body weight also increased by 47% .
This new technology is therefore a remarkable success in research on ecological wastewater treatment and highlights the opportunity to use treated water for fish farming at low cost. Dr Chauhan hopes their microalgae-based bioremediation technique will pave the way for a greener and more sustainable future.
Recover recycled wastewater
Vinod Kumar et al, Sustainable algae-based approach for the simultaneous removal of micropollutants and bacteria from urban wastewater and its real-time reuse for aquaculture, Total environmental science (2021). DOI: 10.1016 / j.scitotenv.2021.145556
Provided by Shoolini University
Quote: A new ecological and sustainable way based on algae to fight against water pollution (2021, September 16) retrieved September 16, 2021 from https://phys.org/news/2021-09-eco-friendly -sustainable-algae-based -pollution.html
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