Thursday, 11 June 2015

Managing Solid Waste in Urban Homes - Part 2 (How do we compost ?)

Many years ago, composting was something that city dwellers knew little or nothing about. More recently when I have been speaking to many people across different apartment complexes, I would hear people speak about composting usually in the past tense ! It turned out that many would have tried and then given up composting due to problems like foul smell or liquid leaching out etc. I could well empathise with them as I too have gone through this journey with several failed attempts at composting.,

As in cooking, composting too has a few recipes which work. The good news is that unlike disasters in cooking (where you might burn your food when you don't get it right),  in composting, even if things go horribly wrong, you will still end up with compost simply because decomposition is a natural process. The difference between doing a good of composting and simply allowing things to decay is how the process takes place. Does it smell bad ? Does it leach ? Is it full of maggots and flies ? If the answer is 'yes' to any of these, then we need to learn our recipe properly.

If we take some wet kitchen waste and close it in an airtight container (or a plastic bag as many people do),  it begins to smell foul because the process of degradation that is taking place is due to anaerobic (lack of air) bacteria. The results of such decomposition are a host of smelly gases and also Methane all of which are harmful to the environment and even the ozone layer. On the other hand, if we take the same amount of wet waste and spread it out in the open, then the foul smell would be drastically reduced or even absent as aerobic decomposition releases mainly carbon dioxide and nitrogen, both of which are odourless (and naturally present in the atmosphere too).

To do a proper job of aerobic composting, the wet kitchen waste which is rich in Nitrogen, needs to be mixed with (approximately half the volume) of dry carbon rich waste such as dry leaves. The dry leaves also help absorb the excess moisture and prevent leaching. Periodic mixing prevents formation of clumps (within which local anaerobic decomposition could happen). If the mixture is managed correctly, you would be happy to see the decomposition process happen not just quickly but also neatly. 

This short video shows how to compost at home without any special equipment. 

If you intend to this for your community, then Prudent Eco Systems has solutions to offer. Do check it out on

Thursday, 4 June 2015

Managing Solid Waste in Urban Homes. - PART 1 (Why should we compost?)

As our cities grow (more in population than in size), it becomes increasingly difficult for the civic authorities to manage the volume of solid waste. Traditionally there have been centralised waste processing centres or even distant dumping grounds.  All this needs to change. The reasons are not complex to understand. 

Most of the solid waste is a mixture of substances which can leach chemicals in to the ground and into our ground water and into the food chain coming back to the very consumers who created the waste. In the process of un-controlled decomposition, gases are released many of which accelerate global warming. 

If an average household generates about 1kg of waste (lets say equal amounts of dry and wet kitchen waste) per day, it will contribute about 365 kg per year to a landfill. Multiply that by the population of few million and we will understand the magnitude of the problem !

The good news is that this is easy to change. The better news is that it is we who can be the change and it all begins in our own homes if we manage our waste wisely. 

The first step is to segregate. Lets see why with a simple example - mix a few common household items -salt, sugar and soap. We have converted three useful items into one useless mixture. Its the same with waste. Wet waste can be composted to give organic manure and dry waste like paper, metal and plastic can be recycled to create new products and reduce our demands on nature. 

If we could also compost wet waste in our own homes and backyards, we would save that 365 kg/yr  of waste from travelling to a far off toxic dumping ground and also the fuel and pollution and traffic congestion caused by the vehicles that carried all that waste through the year !!

So far, we have looked at composting as a means to solve an urban problem of solid waste. However, if we take a more global view, the reasons are more serious. Studies show that the earth is soon running out of topsoil and we have just an estimated 60 years left !! Without sufficient topsoil, agriculture/horticulture would be extremely difficult if not impossible. If we refer to this interview with Prof Crawford, he talks about how the best thing that can remedy this situation is to bring back Carbon to the soil. This is what organic compost will do. It is rich in nutrients like Nitrogen, Phosphates, Potassium (apart from Carbon) and of course a lot of microbes. It can keep people from using chemical fertilisers. 

In another article, lets see how we can compost !