Dumpyards are sore sites. A BusinessWeek magazine article on municipal waste carried pictures of ‘biggest garbage dumps in the world’. Among the worst was of Mumbai’s Deonar, with all its mass untidiness, rising columns of smoke, and scavenging humans, dogs and vultures…
But, then, can landfills be any better? Apparently they can, and in many developed countries, they are maintained so tidily as to be worth emulating. But it is also true that this does not come cheap. The trick is to make the dump pay.
This is what the Hooge Maey project at the Port of Antwerp, Belgium, has done.
A a special purpose vehicle of four municipal authorities and a private Belgian company Indaver, Hooge Maey was tasked to tackle a 40-metre mountain of industrial and municipal wastes that had accumulated over the years at the Antwerp port.
Hooge Maey approached the project with the IMC, that is, ‘isolate, master and control’ principle. Usually, in a landfill, rain mixes with the garbage to form ‘leachates’ that over the years turn to a leachate table.
Since the Hooge Maey waste was piled on an underlying clay layer, the leachate did not seep into the groundwater table. To remove the leachate table, Hooge Maey managers drilled 34 shafts into the dump to pump it out. The retrieved leachate was collected in a buffer tank for further treatment in a biological waste water purification plant.
The waste that was still left in the landfill contained a high amount of organic material. Bacterial degradation of these materials produces methane or biogas. To prevent methane escaping into the atmosphere, with its deleterious consequences, all the shafts were sealed.
Now, the project managers got ready to extract a useful material from the dump yard — landfill gas. Now, four biogas-engines produce 4 MW of electricity. The water purification plant treats leachate water from the landfill and external waste water.
The venture has already turned profitable. The shareholders had put in € 45 million, and over the last ten years, the project has paid them back €60 million by way of dividends. But the authorities are getting read to do more. A solar power plant has been set up on one side of the ‘mountain’ and there are plans for more. Also, given its height, the Hooge Maey plans to set up wind turbines. A demonstration plant for the production of algae for industrial applications has been set up. The other possibilities are algae-fertilisers and livestock feed to name just two.
A good news for India, as Hooge Maey authorities told a team of visiting journalists from India, is that they were willing to offer technology and expertise to India for landfill remediation.
The journalists’s visit was sponsored by VITO, an independent public research Institute on Cleantech and sustainable development, Belgium, and the Government of Flanders (one of the two states of Belgium.)