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Bioremediation for Cleaner Ganga

by Staff Correspondent

The TrickyScribe: Traversing over 2,500 km, from Gangotri glacier in the Himalayas to the Sunderban delta in Bangladesh, the Ganga is lifeline to almost 400 millions of people. But how did one of the world’s mightiest rivers end up as a garbage dump?


Furthermore, floods and droughts, which endanger lives and cause serious damage to crops, livestock and infrastructure, are a common occurrence in the river basin. Changing climate increases challenges proving detrimental to the entire scenario.

Combination of glacial retreat, decreasing ice-mass, early snowmelt and increased winter stream flow continues mounting the pressure. Climate change is already affecting the Himalayan ice cover with a profound impact on the river.

Even as the task of cleaning the Ganga is a daunting one, significant strides can be made toward achieving this.

Animal Carcass

Animal Carcass

According to a World Bank report, a number of government efforts (Ganga Action Plan: Phases I and II) have attempted to address the pollution problem, but the results have been far from satisfactory.

According to a rough estimate, sewage constitutes the largest portion (almost 80 per cent) of the pollution load distantly followed by rural sewage, industrial effluents, cremation of the dead, industrial discharge and agricultural activities. With agricultural activities intensifying in areas near the river, particularly in urban and peri-urban areas, farmers frequently rely on waste water for irrigation.

In addition to the steps taken by the government to clean the Ganga, successful implementation of this task would require partnerships with various stakeholders. Multiple agencies working to address the problem could be brought on board.

Water Quality Chart

Water Quality Chart

The clamour for a cleaner Ganga has gained momentum in recent times. Although huge progress is being made, the need of the hour is to widen our focus. Negotiations on economic revitalization of the Ganga should involve India, Nepal and Bangladesh. The task in itself is of mammoth proportions.

Treating Urban Sewage

Indian states of Uttarakhand, Uttar Pradesh, Bihar, Jharkhand and West Bengal together generate over 7,300 million litres of sewage per day that flows into the river directly or indirectly. Half of this comes from Tier I and Tier II cities like Kanpur, Allahabad and Varanasi.

Alarmingly, the five states together have the capacity to treat only about 3,300 million litres of sewage, mere 45 per cent of the total. The rest flows into the river untreated. This colossal volume might actually be even greater, because large parts of major urban centres like Kanpur and Varanasi are not even connected to the sewage network, and their waste remains unaccounted for.

Condition Prevalent

As many as 33 nallahs and rivulets are to be blamed for the pollution of the mighty Ganges in and around Varanasi in Uttar Pradesh, a South Asia Network on Dams, Rivers and People report said. Sewage systems and treatment plants are going to take several years to be in place and effective.

The river, however, will continue to being polluted till then. Based on its experience in Delhi and Agra, INTACH initiated a month-long pilot project for cleaning wastewater flow in Assi Nadi using the process of bacterial bioremediation.

Assi Nadi is some 3.5 km long and meanders through some very densely populated built up areas directly discharging wastewater into the Nadi. Severe encroachment of the Nadi bed and channel and in the absence of adequate solid waste collection much garbage (including carcasses find their way into the Nadi). Discharge in the Nadi was measured on 3 days for 24 hours each and amounted to 66 MLD (probably 70 MLD as some flow was bypassing the V –Notch). The water is fast flowing owing to the elevation difference of 27m between origin and river level.

The Way Ahead!

Bioremediation, the process of removal of pollutants from polluted water (basically organic in nature) with the help of biological products, might help.

Introduction of bacteria concentrates (a precisely balanced blend of naturally occurring, strictly Anaerobic & Facultative live bacterial strains that start dispersing immediately on dilution with water) degrades organic pollutants, enhances dissolved oxygen levels and removes odors.

Increase retention-time by installing soil bag weirs at three locations – this intervention would create a lagoon on the upstream side allowing settling action as well as greater retention period on the otherwise fast flowing stream

Installation of coir log bundles (using 75 logs dispersed and anchored at 20 locations) – coconut coir logs are biodegradable logs specially redesigned with coco-peat inside the core – serves as a medium for bacteria to reside, grow and treat the pollutants, serves as a filtering medium to certain extent, serves to reduce the velocity of water flow by obstructing the flow.

Manual removal of floating waste – this had to be done to provide an aesthetic appearance as well as retain operational efficiency and also avoid residents’ objections. This is strictly a municipal function which needs to be performed by Municipality regularly and effectively to prevent any solid waste reaching the Assi Nadi.

Namami Gange Projects of Rs 2,000 Crore Approved

Why Bioremediation?

Sewage must be captured and taken to STPs (centralized or decentralized) for treatment, not allowed to flow through storm water channels. The exercise entails individual household connections, sewerage system, pumping stations, STP –  a matter of few years (and being implemented for past 3 decades).

Proposed solution can be implemented in a matter of 2 months and very economically

Significant pollution reduction to the extent of 70% – rest can be taken care of by river’s own natural resilience and self-cleansing capacity

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