Bhoora, Please DO NOT mix PVC with the other fuels to make a 'cleaner' emission oven. It burns to give all sorts of chlorine compounds, pure gas, chlorinated carbons like Carbon tetrachloride. It has to be disposed of very carefully in pyrolytic ovens designed to remove all organochlorine compounds before they reach the open air.

But I am not sure what your goal is. Do you want to burn organically produced fuels alongside inorganically produced ones? Why? Assuming the substance burns to safe products, the cleanliness of the fuel depends on how much organically produced substance is in it. Any fossil fuel added will just burn to carbon dioxide and water, plus a small amount (hopefully) of other gases.

All common fuels contain carbon - it is too widespread to keep out of fuels and burns to a totally environmentally 'safe' product - in moderation. Low carbon fuels are therefore high hydrogen fuels - and there are few of them and they are all nasty like ammonia, hydrazine and so on.

Burning PVC in any case is very harmful for the environment. Please find another way to recycle/reuse PVC if its needed. Cow dung as a fuel is good approach but it needs a lot of energy to prepare (for example drying). You need techno-economic analysis in this case. Generally mixing high calorific fuels with low ones is difficult issue. Please express precisely what is Your goal.

Mixing cow manure with other biomass like wood or plastic reside (e.g., PVC) will not reduce CO2 emission when burned together.

Each of the abovementioned materials gas it own carbon content and, thus, will emit its own CO2. Remember the law of conservation of mass in this example. If you perform an elemental analysis of these chemicals, you can get the carbon content as a weight percent.

In addition to CO2 emission, cow manure, wood, PVC, etc will also emit other gases like nitrogen oxides, sulfur oxide as well as particulate matter.

With respect to the heat content (calorific value) of the mixture, this value will depend on the heat content of each material (cow manure, wood, PVC, etc) mutiplied by its mass fraction in the mixture. You can do a simple Google search for the calorific value of each of these chemicals in order to get the mixture calorific value.

In summary to get an accurate and quantifiable answer to your question, you need to do the following: 1) elemental analysis of these chemical to know the carbon content (wt.% carbon) and 2) the heat content/ calorific value of each of these chemicals.

Hope this helps answer your question.

Professor Yehia Khalil

Yale University

USA

You are burning a valuable fertilizer?  Why? What are you going to use for fertilizer after you burn the cow dung?  Do you expects the crops to obtain all their nutrient requirements from the air?  

You are missing the point of sustainable production. You need to rethink this. 

Bhoora both PVC and cow dung are major CO2 agents regarding emissions. Even under a precise analysis and its combination at any ratio the environmental impact is inevitable. Am in the same opinion with Yahia that a comprehensive analysis to understand the carbon content, calorific value and possibly other traced element especially for the PVC will assist in your proposal.

Sorry I still do not find any logic in your reasoning.  First of CO2 increases are a natural part of the interglacial cycle.  But, if you disagree with that statement; then it does not matter as you will starve to death before the CO2 content gets to high and triggers the greenhouse effect.  Since only 3.34 % of the Earth's surface is productive arable farmland (another 8% is grassland) and global population is anticipated to be approximately 10 billion people by 2050; then I would be more concerned about what your grandchildren are going to eat.  Assisting the decline in soil fertility through buring the nutrients provided by co dung is myopic to me.  Please read Maslow's Hierarchy of Needs.  

Assuming that all carbon eventually transforms into CO2, it should not make much difference whether you burn cow dung by itself or mixed with other fuels.

For that reason, I would not mix it with waste, and especially I would not burn waste in common stoves, see explanation of Tony Maine.

Also, if you burn waste with cow dung, you are loosing the option of using the ashes as a fertilizer.

Cloud Jon - if you use the ashes from burning cow dung as a fertilizer, should that not retain large part of the inorganic nutrients in the field?

You may also consider digesting the cow dung into biogas, burning the biogas in a combined heat and power plant, and using the rest as a fertilizer. In regards to MSW, this should be burned in a properly equipped facility.

Michal,

Methane digestion is a good start at maximizing the cow dung contribution.  Methane can be burned for electrical production and an equal amount of heat by-product.  This is a better "low tech" application.  

Boohoo - The Question is "What is the effect on emission of CO2 when burning of cow dung with various MSW materials like wood, PVC in proportion of 50:50 and burn separately ?".  This question is like unbelievable.  It singular desire to understand the tree while neglecting the importance of the forest.  Or perhaps better said, it is like talking about sex as the only component of marriage.  Such narrow thinking is myopic science and far from Sustainable. Please read my published paper posted on my profile. 

Cloud Jon, I also find the question unbelievable, but at the same time, I respect it as legitimate. We both might find the question of whether to burn hazardous waste separately or mixed with cow dung unbelievable, as in our cultures, most people would not consider either option. There are, however, other regions, where finding fuel to cook food for your family is unbelievably difficult, and it is the top priority. In such conditions, if the only option is to use old tires or other rubbish, people do it, so that today, they can eat and survive. The long-term consequences are of much lesser concern, as there are so many perils that one may not live long enough to be concerned about unhealthy environment shortening their life expectancy. Thinking about what is really sustainable, perhaps burning cow dung (a renewable fuel) in a vented mud stove (fully recyclable and nearly zero embedded CO2 appliance) is far more sustainable than living in a modern house, cooking with natural gas.

Hello everyone

I would like to add one statement and expect your views about it. Everyone has pointed out the use of PVC as a fuel, which is no doubt a bad choice. I'll give a tip for the destruction of PVC before think about this statement.

"Any fuel which contains carbon and it is not one of the fossil fuels, will not make the atmosphere polluted with CO2 provided it is burned completely"

Now let me explain what does it mean.

Any fuel other than a fossil fuel will mainly be a form of biomass (wood, agricultural residue, cattle dung, some kinds of MSW). Now from where did this biomass come? In general the biomass is either direct or indirect byproduct of natural vegetation; plants, trees etc. These plants consume atmospheric CO2 for their growth and reproduction. Thus it can be said that the biomass is indirectly composed as a result of atmospheric CO2. After the combustion (preferably complete combustion) of the biomass, the carbon in the form of CO2 is again released into the atmosphere, which is again consumed and refixed by the plants. Thus it means if one is using Biomass as a fuel and is using it efficiently (No CO is produced), then he/she is not increasing the CO2 levels. In fact, biomass is a Carbon Neutral fuel.

Good thing is that if a fossil fuel is to be replaced by biomass or its derivative, then it will surely reduce the CO2 levels. 

Why is there increase in the CO2 levels when fossil fuel is burned? 

As we all know that fossil fuels were formed a very long time ago with certain conditions of temperature and pressure. Talking about coal, the lowest quality of coal called a Lignite takes around 4000000 years to form and the best quality of coal; Anthracite takes around 46000000 years to form. But it takes only a fraction of a second to burn a significant quantity of such fuels. Thus the carbon obtained from fossil fuels takes a long time to get fixed, due to which the CO2 levels are increased whenever a fossil fuel is burnt. Similar is the case with the liquid and gaseous fuels.

I hope the questioner got his answer.

Best way to carry out the destruction of non-biodegradable wastes such PVC, Polythene, etc. is Pyrolysis. In this process, these non-biodegradable wastes are heated to a high temperature of ~1100-1400C in the absence of air/oxygen. this process breaks the polymers into small hydrocarbon comprising a black/brown colored liquid called as Bio-Crude or simply Bio-oil, which has properties similar to that of petroleum and can be fired directly using modified fuel burners.

I hope that I conveyed my point.

Regards

Harmanpreet Singh

Regarding the effects quality of combustion on climate:

Most of organic compounds and carbon monoxide resulting from incomplete combustion will oxidize into CO2.

Particulate matter resulting from incomplete combustion will have varying effects, black carbon (soot) mostly acts as CO2, although its lifetime is relatively short.

Methane resulting from decomposition of biomass (rather than combustion) also has a similar warming effect as CO2.

Regarding PVC destruction:

While thermal depolymerization seems to be a great technology, it is not commonplace as there are economic barriers, even in the U.S. and the EU.

In answering the original question, I recommend following the concept of "appropriate technology": What technology do we choose for heating the homes and cooking food for families, and what technology do we choose for handling plastic waste, in the given context, which, in this case, appears to be rural India.

This is the real problem we need to resolve, and in the end, we use our "high science" to come up with a practical "low-tech" solution - just like engineers at NASA put their brains together to solve a technology failure in the space using duct tape (for non-US readers: a grey tape originally manufactured to seal ducts, however, due to its excellent properties, it is widely used, notably in low-tech settings such as rural areas, to tape just about anything and everything).