All the pollution parameters show that the Yamuna is dead in its Delhi stretch, and Centre for Science and Environment has suggested measures to clean up the river.
A layer of froth was seen floating over parts of Yamuna in Delhi. Images of devotees thronging the river for the Chhath festival, standing in froth-laden waters, has once again brought the issue of the polluted river back in the glare.
Numerous river-cleaning plans and the money spent on them notwithstanding, the river continues to run dirty.
According to the Centre for Science and Environment (CSE), the cost of 22 km stretch of Yamuna clean-up in the year 2012 is about Rs 3,990 crore as per the data received from the Yamuna Action Plan.
The river, the largest tributary of the Ganga, travels a distance of 22 km through Delhi. It is the most polluted stretch of the river in its long journey. The river’s stretch in Delhi is barely 2 per cent of the length of the total river basin, but it contributes over 80 per cent of the total pollution load in the entire river.
Highlighting the condition of the Yamuna in Delhi, the CSE has maintained that this pollution load is added to the river due to urban and industrial pressures. All the pollution parameters show that the river is dead in its Delhi stretch — the dissolved oxygen (DO), which tells you if the river has life, is zero when the river passes through Delhi.
Delhi takes the river’s water and returns only sewage into it: the barrage at Wazirabad (where the river enters the city) takes water for drinking, and after this the river receives waste discharged from 22 drains.
What causes the frothing in the river?
The frothing is a sign of a polluted river. Release of untreated or poorly treated effluents — household and industrial wastewater — is the reason behind the frothing. Specifically, phosphates in the river form the froth: these phosphates come from detergent effluents from households and industries. At this time of the year, Yamuna has less water flow. As a result, pollutants do not get diluted.
What has been done till now to clean the river?
As per latest (2018) available estimates, Delhi has already spent over Rs 1,500 crore for cleaning the river; this does not take into account the cost of the common effluent treatment plants that have been built in the city. This is possibly the highest amount spent on river cleaning in the country. But it has not worked, as is evident from the pollution data.
In 2005, the Rs 380 crore YAP (Yamuna Action Plan-II) was sanctioned for Delhi. About 50 per cent of this was to be used to rehabilitate 30.2 km of defunct sewers by 2008.
In 2006-07, the Delhi Jal Board (DJB) introduced its interceptor plan to lay over 60 km of sewers along Najafgarh, supplementary and Shahdara drains. According to the CSE, this massive hardware programme, however, has not proved effective in terms of controlling pollution.
An analysis of the biological oxygen demand (BOD) indicates that nothing has changed in terms of pollution load in the river. The load has gone up from about 129 tonne per day in 1982-83 to over 261 tonne per day in 2019.
The Bureau of Indian Standards (BIS) has set down quality norms for soaps and detergents, and the Delhi Pollution Control Committee (DPCC) has now banned the sale of soaps and detergents that do not conform to those norms. But will these standards be enforced and the ban implemented? That is anybody’s guess.
According to the CSE’s problem analysis, Delhi has already built 17 sewage treatment plants (STPs), which together add up to 40 per cent of the total installed sewage treatment capacity in India. But these plants remain grossly underutilised. The city does not have the drainage to transport all its excreta to the treatment plants.
A majority of Delhi lives unconnected to underground drainage or lives in what is called unauthorised and illegal colonies. The sewage from these areas — untreated — flows into open drains crisscrossing the city. But these are the same drains, flowing past colonies, in which the STPs dispose of their treated effluent.
In this pollution scheme, the illegal unconnected waste of the majority is being mixed with the treated waste of the minority. The result is obvious: growing pollution in the river.
We can never clean the Yamuna until we can treat the sewage of all in the city. But this will require providing drainage to all, and sewage treatment for all, CSE maintains.
Drawing out a viable action plan for Delhi’s Yamuna, CSE said “we need to change the art of pollution control. We need to chalk down the strategy for business-unusual so that we can spend more money but get a living and breathing river in return.”
Provide water in the river for dilution of waste: rivers need water to assimilate the waste. Today, Delhi takes water from the Yamuna, upstream of Wazirabad, and returns only sewage to it.
Between the two barrages — Wazirabad and Okhla — there is no water. There are only some 17 drains that bring sewage into the river.
“Even if we were to treat every drop of waste before it reaches the river, it will do nothing. The river must have water to dilute the waste,” CSE stated.
There are two ways for Delhi to get water in the river. One, it can demand Haryana gives it more water. But this will be difficult. The second option is that Delhi can begin to reduce its own water demand and build water harvesting for capturing rainwater for discharge in the lean season, so that it can allow water to flow in the river. This can be done.
Maximise the utilisation of the existing STPs: there should be ways for bringing waste to the plants, by lifting it from open drains, not just waiting to build new ones or building and repairing more drains.
The sewage should be intercepted from the drains. The hardware approach needs to go. Treat all sewage by intercepting from open drains, not by building interceptors to existing drains and pumping waste to existing sewage treatment plants.
Treat but do not discharge into the drains: the treated effluent must not be put back into the same open drain, which carries the untreated waste of the majority.
“Today, we spend huge money first pumping sewage long distances for treatment and then waste this effort by dumping the cleaned water in unclean drains,” CSE said.
Sewage is treated at the Yamuna Vihar plant in east Delhi, and disposed off in the drain carrying untreated waste outside the plant. Then the same waste is treated further down in the Kondli treatment plant. Cleaned effluent is then dumped into a drain, which flows past the new colonies of Noida, which add more discharges. By the time it reaches the river, there is only sewage in the drain, no water.
Recycle and reuse the treated waste: all treated waste should be reused and recycled, as far as possible locally so that costs of pumping are reduced. In other words, sewage must be reused in gardens, in lakes or in industry. STPs must be built only when they have been planned for reuse.
CSE suggested that treatment of sewage directly in the open drains that crisscross the city. So, instead of waiting for every open ‘storm water’ drain to go underground and disappear, the system will ensure all waste is treated and cleaned as it flows through the city.
Therefore, plan for in situ drain treatment, as it will bring down pollution levels of discharge that is not intercepted. The bottom-line: use the open drain for treatment of waste. This would mean using innovative technologies for bioremediation (‘green’ plants) and oxidation to decompose and degrade sewage.
“We should build STPs close to the banks of the river to treat whatever waste remains in the drains. This would mean using technologies, which need less land to treat sewage,” it said.
The design would be not to discharge anything but treated effluents in Yamuna. The treated waste should be put into the river for dilution.