Returning Life to Soil: Converting Municipal Organic Waste to Biochar for Environmental Management and Sustainable Agriculture

Conference paper

Author: Mahmudul Islam Piash

Department of Soil, Water and Environment, University of Dhaka, Dhaka- 1000, Bangladesh.

Abstract:

The basic idea is to return the carbon and nutrients back into earth from where they were originally generated and are usually considered as waste. Daily, vast amount of municipal organic wastes are produced throughout the world. These are normally dumped at landfill sites and cause environmental problems. Besides, application of untreated organic wastes into soil is an unsustainable practice. However, proper modification could convert these to a potential soil amendment. These demand a unique technique of bio-resources management that would sequester carbon and nutrients in soil for years to come and ensure quality food production. Therefore, producing Biochar (thermo-chemical conversion of Biomass) from municipal organic wastes might be a reasonable option for hazard-free waste management. Aside from this, incorporation of Biochar improves physicochemical properties of soil, supplies adequate macro and micro nutrients, and reduces the agricultural emission of greenhouse gasses.

Introduction:

The two biggest challenges of this century are to combat with the changing climate and sustain food production for increasing number of population. To increase agricultural production, soils must be kept healthy. Organic matters are considered as the life of soil which potentially helps to sustain food production. But the climatic condition and existing management practices of our country don’t allow organic matter to be sequestered in soil for long. Moreover, unavailability of adequate biomass makes the addition of organic matter rather difficult. Carbon stored in Biochars can also be sequestered in soil for hundreds to even thousands of years (Preston and Schmidt, 2006), otherwise that would eventually return to atmosphere by natural decomposition.

The idea is supposed to solve two major problems of the country. Those are:

Ø  Increasing amount of municipal wastes (22.4 million tons/year) in major cities and consecutive environmental issues caused by leachate and greenhouse gas emission from landfills (Waste, 2012).

Ø  Growing threat towards existing food security due to climate change, reduced arable lands, soil degradation, scarcity of water, salinity intrusion and agricultural mismanagement.

What is Biochar?

Biochar is simply defined as a carbon rich by-product obtained by thermo-chemical conversion of biomass in oxygen limited condition for C sequestration or agricultural or environmental management purpose.

Fig. 1: Terra Preta (Source: www.mavitecgreenenergy.com)

Historical Background of Biochar:

The idea of Biochar is a bit old. It was used as a soil amendment for at least 2000 years ago by ancient tribes in the Amazon basin called Terra Petra (Glaser et al., 2002).:

Idea Demonstration:

Fig. 2: Demonstration of the Idea

Steps to Idea Implementation

Raw material separation

Two methods could be utilized for separation of municipal organic wastes. One is the source separation at production facilities; widely used in developed countries.  The other one is the separation at disposal sites which is currently more suitable for Bangladesh. The largest landfill site of Bangladesh at Matuail in cooperation with JICA is expecting to use a new waste separation technique (Refuge Derived Fuel- RDF) to separate organic and utilizable wastes from bulk mass. That would facilitate trouble-free collection of biomass for Biochar production at dumping stations. The following diagram shows a demonstration of RDF seperation technique. 

Fig. 3: RDF separation method (Source: Pyrocrat)

Biochar production

Biochar production is fully scalable. Pyrolysis ovens are becoming available in all sizes, mobile and stationary: from cooking stoves to industrial-sized units for power generation.

Fig. 4: Process flow diagram of Biochar Production (Source: International Biochar Initiative)

A full scale commercial Biochar production unit may look like the following unit. Setting up a industrial pyrolyzer at dumping stations might be effective.

Fig. 5: A commercial Pyrolyzer  (Source: dglikes.wordpress.com)

Benefits of Municipal organic waste Derived Biochar

The benefits are two folds: better waste management and improved productivity.

Waste management benefits

If proper management approach can be taken, these wastes would be converted to revenue generating source to waste managing authority (City corporations). Appropriate approach would reduce the need of the waste dumping sites, lower the spreading of hazardous leachate, produce energy, reduce the emission of GHG's from landfills etc.

Fig. 6: Waste managing benefits (Source: www.ngi.no)

Soil amendment benefits

When applied to soil, Biochar adds the fuel for biological life processes. It also improves water holding capacity, raises pH, CEC, specific surface area etc. Moreover, it’s a source of essential nutrients specially the micro’s.  A comparative study on Biochars produced from different feedstocks showed unique porosity and Domestic organic waste derived Biochar’s highest nutrient status.

 

Fig. 7: Nutrient content & SEM images of Biochar (Piash et al., 2016)

Limitations of Biochar

The major limitation in Biochar production is the unavailability of biomass and energy-requiring production technology. Sometimes, Biochars might contain pollutants if the feedstocks weren’t carefully selected. Moreover, Biochars when applied for the first time, can reduce yield.

Conclusion

A little effort to incinerate biomasses in a partially closed chamber would produce Biochar that can mitigate many problems. Production of Biochar from municipal organic wastes would facilitate one of the best waste management practices, ensure Bangladesh’s contribution to mitigate climate change and enhance soil productivity in a sustainable way.

References:

1.  Glaser, B., J. Lehmann and W. Zech. 2002. Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal-A review. Biol. Fertil. Soils. 35: 219-230.
2. Piash, M. I., M. F. Hossain and Z. Parveen. 2016. Physicochemical properties and nutrient content of some slow pyrolysis biochars produced from different feedstocks. Bangladesh J. Sci. Res. 29(2): 111-122.
3. Preston, C. M. and M. W. I. Schmidt. 2006. Black (pyrogenic) carbon: A synthesis of current knowledge and uncertainties with special consideration of boreal regions. Biogeosciences. 3: 397-420.
4. Waste Atlas. 2012. Country Data: Bangladesh.

Impact of climate change in coastal area of Bangladesh and achievement from COP19

The most of the parts of Bangladesh stands on the coastal area. Large number of people lives and directly related with various kinds of occupation associated with sea or coastal. But recently it has faced some problems which were great threat for the existence of the ecosystem as well as the living peoples.

This was happened for climate change. Sea level rise is one of the most reason for the climate change, which impacts suffer Bangladesh very much.

·         Harsh coastal stroms

·         Strong coastal stroms

·         Heavy rain

·         Flooding 

Associate stroms increase dramatically. Recently happened (Sidr, Ayla )  come here with lots of tears for the mangrove forest( Sundarban),its close coastal area.  We can see their ruins in sea site forest of Sundarban. Many trees destroyed, people become homeless for these stroms.

Another most important issue is the flooding of coastal area. The technaf area is going to be flooded where lives almost 2,00000 peoples those are directly related with fishing and agriculture. But they always straggle to survive. Most of the areas are almost go to the belay of sea for sea level rise. The people remain always in a funk.

Another problem is the decrease of soil fertility for inter of saline water into agricultural soil. So many  farmers become helpless by the lost of the land.

 

“To invite all parties or intensity domestic preparations for their intend nationally determine contribution” -  the conclusion by this line from COP19 , we can estimate that the developed country will helps financially, but will be it very much helpful for us when we continuously lost our land?

The Warsaw COP, it was expected, would chart a new paradigm of climate finance including by way of a financing roadmap for climate related activities between 2014 and 2020,in addition to the promised US$ 100 bn/year by 2020. This has not happened. The only solace was that the Adaptation Fund Board had given a drive and managed to obtain commitment for US$ 100 million. The most relevant decision on long term finance was the following:

"Decides to continue deliberations on long-term finance and requests the secretariat to organize in-session workshops on, inter alia, strategies and approaches for scaling up climate finance referred to in paragraph 10, cooperation on enhanced enabling environments and support for readiness activities, and on needs for support to developing countries, from 2014 to 2020. Further requests the secretariat to prepare a summary of the workshops for consideration by the Conference of the Parties and to inform the ministerial dialogue referred to in paragraph.

Bangladesh participated in COP19 not only in negotiation but also in many other activities. The group of about 130 participants from Bangladesh and elsewhere organized a side entitled “climate initiatives of Bangladesh: experience of finance, adaptation and migration”.

 The role of Bangladesh was highly appreciated in CMP plenary for its ratification of second commitment period of Kyoto protocol. The secretary general of UNFCCC appreciated this initiative by Bangladesh very much.

Financial help for the developing country is not the main solution for the impact of climate change, we need less production of  CO2 that can gives us much pleasure as we as to built up a pacifying world.