The Criticality of Composting

In 2011, the 27 states in the European Union composted on average 15 percent of municipal waste, with Austria composting 34 percent, the Netherlands 28 percent, and countries like France, Spain, and Germany each composting about 18 percent.

A 2019 article said that India produces 1.5 lakh tonnes of solid waste every day and its biodegradable fraction can be upto 70 per cent for various Indian cities. Not even 5 per cent of organic waste generated by cities is converted into compost in India, even though the Swachh Bharat Mission has committed to ensuring that all organic waste produced in Indian cities is processed into making compost.

Landfilling, although according to the waste hierarchy the worst option, is still the most used MSW disposal method in the EU. Landfills need to be constructed and operated in line with the EU Landfill Directive (impermeable barriers, methane capturing equipment) to avoid environmental damage from the generation of methane and effluent.

Bio-waste is a putrescible, generally wet waste. There are two major streams – green waste from parks, gardens etc. and kitchen waste. The former includes usually 50-60% water and more wood, the latter contains no wood but up to 80% water.
As the efficiency of incineration is lowered by the moist bio-waste, it can be beneficial to remove bio-waste from municipal waste.

Waste to Energy (WtE) plants need waste of high calorific value and low moisture content to generate electricity. Only non-biodegradable, non-recyclable waste should be sent to these plants, as per the Solid Waste Management Rules, 2016. This would include only non-recyclable plastics, polymers etc.

But in India, it’s mixed waste that’s sent to WtE plants. And this mixed waste (not considering inerts) has high vegetable and wet waste content – close to 60-70 percent. Whereas non-biodegradable non-recyclable waste comes to less than 10 percent of the mixed waste.

Moreover, as the waste is mostly unsegregated with high wet content, it’s unsuitable for burning. To burn, extra fuel is needed, which would make power generation itself inefficient.

Middle-class residents in big cities generate nearly 0.8 kg of waste per day. And nearly 60% or more of the daily waste generated in households is made up of organic matter.

With increasing food demand and depleting soil quality, city compost plays a very important role as a replacement or supplement to chemical fertilisers in replenishing the nutrient-depleted soil.

Sequestering Carbon in Soils

There is increasing emphasis on identifying strategies that will reduce the rate of enrichment of atmospheric CO2 by offsetting emissions caused by humans.

Major human caused sources of increasing CO2 equivalent emissions include the combustion of fossil fuel, cement manufacturing, deforestation and the burning of biomass, and land-use conversion including drainage of peatlands, soil tillage, animal husbandry.

We need to reduce CO2 , Methane  and Nitrous Oxide emissions and offset emissions through sequestration of carbon in soils and other terrestrial and inland aquatic ecosystems.

Land-use change, deforestation and soil cultivation have added CO2 equal to nearly 50 % of that caused by fossil fuel burning. Current rates of these activities are equal to 20 % of the emissions caused by fossil fuel burning. 

The Earth's natural systems, other than oceans and atmosphere, absorb over a third of the greenhouse gas emissions caused by humans every year. However the nearly two-thirds of the emitted carbon is added to the atmosphere and oceans every year and is fast pushing earth into a hot house state. 

Why 2 min / 24 hrs / 10 days electric composting machines being sold in India are a SCAM !

Laughably, Excel Industries sells a composter claiming to compost in 2 MINUTES ! (apart from Excel machines claiming to compost in 24 hours / 10 days). 

There are many other companies in India making similar claims - for example Alfa-Therm sells machines claiming to compost in 24 hours / 10 days. 

All of these machines are SCAMS, claiming to compost in 2 minutes / 24 hours / 10 days. Here is why i say this : 

1. No scientific study in the world claims to complete composting of organics in less than 2 weeks. 

2. Even where machines have been used for composting in a few cases in the west, the wet waste undergoes processing INSIDE the machine from 10 - 14 days ATLEAST. After that it undergoes further curing outside for some weeks. 

Please note that such a length of time to compost is far more than the manual aerobic process employed in revolving drum composting, where composting AND curing are completed in 20 days after the bin is full. 

3. ALL studies say that no shredding is required for kitchen wet wastes so one of the claimed functions of these machines is useless for this purpose. Studies ALSO say that no enhancers are needed for kitchen wastes which are teeming with microbial life. So this so-called function of these machines is also not of any use. 

4. Some of these machines provide artificial heating for composting which is a ridiculous proposition - when massed together, wet wastes with free flow of oxygen around them, teem with microbial life NATURALLY. 

In manual composting, the compost pile heats up within the first 4-5 days from the activity of numerous organisms breaking down organic matter - temperatures are typically over 50 degrees C when manual composting is done right.

5. Finally, the machines claim to mix all the wet wastes together - but they do it only during the duration of the wet waste in the machine which is only 2 min / 20 min / 24 hours. 

Mixing - which forces oxygen through the wet wastes, increasing microbial activity, is required throughout the composting operation. Only the revolving drum process achieves that, not ANY of these machines. 

6. The machines are NOT labour saving at all - the 10 day composting machine demands labour add only 55 kgs to it at a time, wait for 20 minutes, then cart the effluent from the machine in several baskets to a curing rack. This is not needed in a manual aerobic revolving drum process - once you put the wet wastes in, they only come out fully usable. 

One wonders what half-baked 'compost' will result at the end of 10 days as there is no daily mixing of wastes unlike in revolving drum system (the baskets in the machine system stay stationary). 

7. Further, in the 10 day machine system, the stationary baskets are automatically sprayed with water every 90 min, or so the company literature says. That is an astonishing step to take : wet kitchen wastes require NO water addition, studies say. 

In fact all this extra water addition will create anaerobic conditions which will :

A. Halt aerobic composting. 
B. Give rise to methane gas which is the same as PNG supplied in pipes for cooking across Delhi and surrounding towns. Methane is highly inflammable - which is why dumpsites across india where wet wastes are dumped, are always on fire. 
C. Produce ammonia, which is a highly irritating gas with a pungent, suffocating odor.
D. Produce some half-done wet mass in the end which cannot compare with aerobically produced compost which does enormous good to soils.

Aerobic manual composting done right produces no smell, no nuisance, and quickly converts wet wastes into compost. No power is needed and very simple equipment made from recycled wastes suffices.

In contrast, these machines, especially the 24 hour composting ones, use humongous amounts of power, which flies against the need to bring down electricity use - to save India from heating up due to coal burning.

The machines can also end up burning plastic wastes alongside wet wastes during heating, releasing noxious cancerous fumes. But even the machine variants that claim to not heat the wet wastes, do not follow scientific composting guidelines. 

Aerobic composting is important for saving the earth from heating up as well - a set of recent studies showed that compared to the current dumping of wet wastes (shown in blue), aerobic composting will result in a massive amount of less carbon in the air (shown in green) over 20 years.

That is because the present dumping of wet wastes  is generating a high proportion of methane, 30 times as effective at warming earth as CO2. The wet waste dumping is also generating a huge amount of nitrous oxide gas, which is 300 TIMES as effective as CO2 at warming the planet. 


In fact, if all the presently dumped organic wet wastes were AEROBICALLY composted, that would result in the sequestering (capture from air) of a huge amount of CO2 as well.

While the study pertained to California, it surely has implications for the rest of the world. 

CORRECT MANAGEMENT IN YOUR KITCHEN OF SEPARATE DRY AND WET WASTE

I was following up with a neighbor on keeping the wet and dry waste separate in his flat kitchen. We had last spoken on global warming a few weeks ago. He is a very conscientious man, doing a lot of good to the environment. But these were the mistakes he was making with wet and dry wastes (which hopefully would be corrected after yesterday’s conversation) :

·       He had kept two waste bins for wet and dry waste – one green, one blue. I explained it was not necessary to keep two separate bins – as the waste collector did not have two separate receptacles to collect wet and dry waste and the wet and dry wastes would be mixed in his cart.

·       A big plastic packet would be best for dry waste, hung at the tap below the sink – the kind of packets we get with presents or with big items we buy. we can even buy and keep such packets – as this one plastic packet will save all the rest of the dry waste from being mixed with wet waste and will be recycled itself in any case.

·       The neighbour had not monitored that his maids were putting dry and wet wastes in the different spaces for them correctly. One needs to check for about a week or so and then everyone is habituated.

·        His wet waste bin had a plastic packet into which the wet waste went and was given to the waste collector. I told him plastic mixed in wet waste would keep it from composting in oxygen rich conditions which was best. When wet waste was buried below plastics, the wet waste composted without oxygen – giving rise to lots of methane which was lethal for global warming.

·       In our home we just tear up newspapers in napkin sized pieces, kept ready in a stack in kitchen for various tasks. Such newspaper pieces went to the bottom of the wet waste bin and sides also if needed after it had been washed and dried. They kept the bin from getting too dirty and could be composted with the wet waste.

·       The neighbor was giving out the dry waste daily even if in a separate packet. I told him such small packets would not be collected by rag pickers and would remain mixed in wet waste. Dry waste needs to be stored in the kitchen only in big packets and till it is stuffed full. Takes about a week or so until it is a big bag. Then it has to be securely tied on the top and given to waste collector. Such a bag is worth 100-150 rs. to the ragpicker and is immediately plucked out and processed for the recycling industry.

CORRECT MANAGEMENT IN YOUR KITCHEN OF SEPARATE DRY AND WET WASTE KEEPS YOUR KITCHEN DRAIN CLEAN, YOUR WET WASTE BIN CLEAN AND NOT OVERFLOWING, AND GIVES YOU THE SATISFACTION THAT YOUR WASTE IS NOT CONTRIBUTING TO GLOBAL WARMING MUCH. AND IT SUPPORTS POOR PEOPLE. IT IS EASY – WE HAVE DONE IT FOR 18 YEARS. 

Sharp rises in levels of methane

Sharp rises in levels of methane – which is a powerful greenhouse gas – have strengthened over the past four years. 

Some researchers believe the spread of intense farming in Africa may be involved, in particular in tropical regions where conditions are becoming warmer and wetter because of climate change. 

Rising numbers of cattle – as well as wetter and warmer swamps – are producing more and more methane, it is argued. 

If nothing can be done about the rise in methane levels, then even more cuts will have to be made in CO2 emissions. 

Methane..

Methane accounts for 20% of the total radiative forcing from all of the long-lived and globally mixed greenhouse gases.

Methane is a potent greenhouse gas. Carbon dioxide is the main one, because the atmosphere holds 200 times as much of it. But a given amount of methane traps at least 25 times as much heat—unless you burn it first. Then it enters the atmosphere as CO₂.

A lot of methane is being burned these days. In the past decade the technology called hydraulic fracturing, “fracking” for short, has enabled drillers in the United States to extract natural gas from deeply buried shales they couldn’t tap before. Natural gas supplies have surged; prices have plummeted. Fracking is now spreading around the world, and it’s controversial. The gas boom has degraded landscapes and polluted water. But it has also had environmental benefits. Natural gas burns much cleaner than coal. In part because American power plants have been switching from coal to cheap gas, U.S. emissions of CO₂ from fossil fuels fell last year, even as the world set another record.

Are emissions from Nitrogen fertilizers all that bad ?

Nitrous oxide gas should not be confused with nitric oxide or nitrogen dioxide. Neither nitric oxide nor nitrogen dioxide are greenhouse gases, although they are important in the process of creation of tropospheric ozone which is a greenhouse gas.

Nitrogen (N) use in agriculture substantially alters global N cycle with the short- and long-term effects on global warming and climate change. It increases emission of nitrous oxide, which contributes 6.2%, while carbon dioxide and methane contribute 76% and 16%, respectively of the global warming. However, N causes cooling due to emission of NOx, which alters concentrations of tropospheric ozone and methane. NOx and NH3 also form aerosols with considerable cooling effects.

Thus net global temperature change potential (GTP) over a 20 year time-scale is lower by 6.9% and that over a 100 year time-scale by 2.4% compared to the GTP considering nitrous oxide emission alone.

Are you unnecessarily contributing to global warming by not keeping your waste segregated ?

Solid wastes generate greenhouse gases such as carbon dioxide, methane, and small amounts of nitrous oxide. The global warming potential of methane is 25 times as much and nitrous oxide, 298 times as much as that of carbon dioxide.

Disposal of mixed waste including biodegradable matter (sometimes as high as 60 per cent) in dumpsites across India provides a perfect anaerobic environment for generation of methane and leachate. One tonne of biodegradable waste releases 0.84 tonne of carbon dioxide equivalent emissions if left to decompose anaerobically (in the absence of oxygen when buried in deep pits).

The volume of waste sent to the landfill sites can be reduced if biodegradable waste is processed locally to produce compost. Compost helps store carbon back in the soil. Its usage reduces the need for chemical fertilisers which emit large quantities of nitrous oxide — both during production and in application— and thereby helps mitigate emissions. Compost also improves moisture retention in the soil. We are losing out on mitigation through composting because at most only two per cent of the municipal solid waste in India is composted.

Recycling of dry waste also helps reduce greenhouse gas emissions because the energy required to manufacture a product using virgin materials is higher than when using recycled materials. While India has had a tradition of recycling paper, glass, metals, etc with the engagement of the informal sector, lack of segregation comes in the way of realising the full potential of recycling.This is particularly true for paper that soils easily when waste is mixed. As a result, only 27 per cent of paper in India is recycled, compared with 60 per cent in Japan and 73 per cent in Germany. Recycling requires up to 50 per cent less energy compared to production of paper based on wood pulp, and it also saves trees from being cut.