RESEARCHERS of Bhakta Kavi Narsinh Mehta University (BKNMU), Junagadh have developed a bio-coagulant from seeds of drumstick (moringa oleifera) which has been found to be very effective in treating domestic wastewater without generating any non-bio-degradable slurry.
As part of their research, the team collected samples of domestic sewage from Junagadh city and then treated the sample wastewater by adding the powder of matured, sun-dried drumstick seeds in laboratory setup.
Drumstick seeds were ground into a powder to be used as a bio-coagulant for treating domestic wastewater through aerobic processes.
The team comprised of Vaishali Varsani, a doctoral research scholar with the department of life sciences of BKNMU, Dushyant Dudhagara, an assistant professor, and Prof Suhas Vyas, head of department of life sciences at BNKMU.
The researchers found that moringa oleifera seed powder (MOSP), thanks to its properties, triggers coagulation and flocculation of organic matters and colloidal particles in wastewater resulting in sedimentation of suspended matters and thereby removal of turbidity of water.
MOSP achieves this by destabilising colloids through its cationic protein which is positively charged and acts as a magnet for negatively-charged colloids in water.
The researchers treated MOSP with HCL (hydrochloric acid), NaOH (sodium hydroxide) and NaCL (sodium chloride) for enhancing its potential and then conducted the laboratory experiment of treating one litre of wastewater with the help of one gramme of MOSP.
They also conducted experiments of treating wastewater by plain or natural MOSP.
The experiments suggested that HCL-treated MOSP removes turbidity of wastewater by 84.48 percent to 93.69 percent.
Turbidity refers to suspended matters in water that makes it muddy and imparts a grey colour.
The researchers also observed that HCL-treated MOSP reduces biological oxygen demand (BOD) by 27 per cent while reducing chemical oxygen demand (COD) by 45 per cent.
Similarly, they also observed that NaCL-treated MOSP reduced total suspended solids (TSS) by 97 milligram (mg) in a wastewater sample having TSS in the range of 97 to 133 mg.
They also concluded that NaOH-treated MOSP reduces the total dissolved solids (TDS) to 237 mg from 954 mg in the sample of untreated wastewater. Similarly, HCl-treated MOSP was found to have reduced pH (proton concentration) from alkaline 8.03 to near neutral pH of 7.14 pH.
The experiments revealed that MOSP coagulants purify domestic wastewater to standards significantly higher than those prescribed by the World Health Organisation. For example, MOSP managed to bring the nephelometric turbidity unit (NTU) from 20.6 to 1.3 NTU, which is better than WHO-prescribed turbidity of 5 NTU for drinking water. It also brought down the pH value to well within the WHO recommended range of 6.5 to 8.5.
The findings have been recorded in a research paper submitted in March this year and published in US-based Heliyon journal, last month.
The researchers argue that activated MOSP bio-coagulants provide an effective alternative of inorganic chemical coagulants like potassium aluminium sulphate and iron chloride, iron sulphate, slaked lime, polysalts etc, as treating wastewater through such inorganic chemicals generates excessive non-biodegradable sludge, the researchers note.
Newsletter | Click to get the day’s best explainers in your inbox
“The highlight of our research is that moringa oleifera seeds, which are generally considered a waste, can be a very effective and economical option of inorganic chemicals in treating domestic sewage. Seeds of drumstick will find an alternate use and we will have a product which will treat wastewater without the hazards of chemicals,” Prof Vyas told The Indian Express, adding, “We are testing the MOSP in larger samples.”
Presently, civic bodies treat domestic wastewater through its sewage treatment plants using activated sludge process, which is an anaerobic process, and sequential batch reactor (SRB) technology which is an aerobic process. However, these STPs generally chlorinate the treated wastewater to remove any pathogens before discharging it.
Separate Vidarbha team seeks help from Kishor