The power of friendly bacteria present in effluents flowing into the national river Ganga can be harnessed to combat the very same pollutants. That is what a study by a BHU assistant professor has concluded.
The bacterial population, which feeds and multiplies on these effluents, can be used to develop a microbe-based cleansing technique.
For that, these bacteria would have to be isolated from others present in the water, grown and later re-released into the effluent being discharged in the river.
Once that is done, the assortment of useful bacteria in the effluents can bring down organic load and heavy metal content flowing into the Ganga to a safe/permissible level. These bacteria are present particularly in the Assi nullah at Varanasi.
The study by Dr Asha Lata Singh, assistant lecturer of Environmental Science at the Department of Botany, BHU, was conducted in 2009. It has traced alarming levels of heavy metals and organic load in the national river at Varanasi.
The increasing organic load on the Ganga is caused primarily by industrial effluents and heavy metal contamination. Dr Singh used samples of Ganga water collected from 24 prominent ghats dotting the national river in Varanasi in 2009.
Singh told HT, “All we've to do is to use the bacteria-based microbial cleansing technique in two phases - first at the industrial units discharging water into the Ganga and then at Sewage Treatment Plants (STP) that will perform microbe-based treatment of the sewage finally flowing into the river.”
“A mixed consortia of bacteria found thriving in the Assi nullah flourish by using the organic load in the water as nutrient to multiply their population. Also, these bacteria, through the process of surface absorption of heavy metals, further clean the effluents/sewage flowing into the river,” Singh added.
The industrial units polluting the river can use this bio-remediation power of the microbes to ensure that the water being discharged is not noxious. Treating the water at the sewage treatment plants, via the same natural technology, can further bring down all contaminants to a safe level, that too at a lower cost.
The microbes/bacteria can be used for developing bio-fertilisers too. Singh said the water samples were studied for the level of heavy metals, including iron, manganese, lead, cadmium, copper, chromium and zinc. The samples were collected from Harishchandra, Kedar, Chauki, Pandey, Chassati, Darbhanga, Ahilyabai, Dashwashamedh, Rajendra Prasad, Laitha, Samne, Assi, Rewa, Tulsi, Bhadaini, Jain, Shivala, Chetsingh and Hanuman ghats among others.
Examination of the samples revealed the iron content was above the permissible limit (0.3ppm). The maximum concentration of 1.981 ppm was found at Rewa Ghat. The level of copper was found above the permissible limit (0.05ppm) in 23 samples. The maximum concentration of 0.168 ppm was found at Assi Ghat.
The concentration of chromium was above the permissible limit (0.05 ppm) in 13 samples. The maximum concentration (0.072 ppm) was at Anandmayi Ghat. The lead content was above the permissible limit (0.05 ppm) in all samples with the highest (0.84 ppm) at Assi Ghat, which was 16.8 times more than the permissible limit.
Cadmium too was found above the permissible limit (0.01 ppm) in 14 samples, the maximum (0.051 ppm) being at Chet Singh Ghat. About the health hazards of water contaminated by heavy metals, Singh said lead caused convulsions and renal failure, besides affecting mother's health during pregnancy, as well as foetus growth.
Excess cadmium excess can lead to testicular degeneration, prostate cancer and renal damage. According to research, use of heavy metal-laden Ganga water was causing carcinoma of the gall bladder in East UP and West Bihar.