Bioremediation can close dumps, but what about the city’s garbage?

Dr Sultan Ahmed Ismail, soil biologist and Director - Ecoscience Research Foundation, said bioremediation is an internationally recognised process, where a selected group of micro-organisms are introduced and monitored over a period, to clean up the contaminated soil. “The problem with our dump yards is that there has been indiscriminate dumping of garbage – from hormonal tablets and hospital waste to plastic to organic waste. So, while conducting the bioremediation, we don’t know what the end-result of the process will be. Another way of bioremediation is to scoop out the garbage, introduce the microbes, seal it and after some time, use the  residue as compost. But in our dump yards, this must be done with caution and only after thorough testing, because it has been proved that there is presence of heavy metals. If these metals are used in agriculture, it can lead to soil contamination and enter the food chain. We need a regulatory body to supervise the process and make periodical reports to the government. The TNPCB too should be involved,” he said. 

An environmental study conducted by IIT Madras found heavy metal concentration, in the groundwater around Perungudi dumpsite. The ongoing study, which started in 2014, revealed that the groundwater contamination spread to other parts of Perungudi, as the soil leaches during the rains. This carries the contaminants to nearby areas. If there is groundwater contamination, the soil quality also is very poor. 

Dharmesh Shah, waste policy expert, said that while bioremediation is the right way to go about closing a dump, there is a lack of sustainable waste management plan in the city. “Bioremediation is not an overnight process – it happens in a phased manner. However, it is alarming that the city doesn’t have a waste management plan. We need to have source segregation along with collection points and waste disposal in a sustainable manner. Until the residents, contractors and other stakeholders get used to a sustainable waste management system, there will be a need for an alternative dumpsite. But despite such urgency, there has been no move to form a committee to draft the waste management policy, even after the sixmonth deadline as mandated by the Solid Waste Management Rules 2016,” he said. 

Chennai’s mammoth garbage problem is evident in the number of waterbodies and marshlands, turning into trash zones. Pallikaranai marshland has turned into an unofficial dumping ground. The commuters, who use this road, complain of smog caused by burning the garbage. Saravanan, an IT employee, who commutes using this road, said, “There is reduced visibility as fogginess is caused by burning the garbage. Sometimes, it is so bad that we have to wear a mask. There are a lot of insects flying around, which gets worse during the rainy season.” 

In the past, the city’s garbage dumps have been successfully remediated to parks. Point in case, the Tholkappiar Poonga set up by the government in the Adyar estuary area. Until 2007, the area was a garbage dump yard and sewage pit. However, the team from Chennai River Restoration Trust (CRRT) working on the bioremediation started by stopping the flow of waste and clearing the debris. A survey of the species present in the area was done, to aid regeneration efforts of native flora and fauna. Today, the park is a green space in the concrete jungle with more than a hundred species of birds.