Premium Biochar and Compost Production from Organic Waste Processing

Biochar and compost production both use organic materials. The difference lies in their compatibility level. Wet, nutrient-rich organic materials with little lignin are more suitable for compost production. Dry, lignin-rich organic materials are more suitable for biochar production. Therefore, sorting these organic materials is necessary to achieve optimal results. With organic waste comprising up to 60% of municipal waste, the raw material requirements for both biochar and compost production are estimated to be substantial.

Biochar production is a thermal process, while compost production is a biological process. A biochar production unit, a pyrolysis unit, can be installed adjacent to and integrated with a compost production unit at municipal waste treatment facilities and similar facilities. The biochar product is then used to produce compost, improving the quality of the compost to premium compost and accelerating composting times. For more details, read here. Premium compost can also be sold at a higher price commensurate with its quality. Excess energy from biochar production or pyrolysis operations can be utilized in the waste processing of RDF fractions or others. 

The production potential of this premium compost is enormous. This makes it suitable for use on critical land from post-mining reclamation, which covers millions of hectares, or even hundreds of millions of hectares of degraded drylands. When premium compost is applied to unproductive or less productive land, it becomes fertile. For example, revegetation of post-mining reclaimed land will yield a variety of agricultural or plantation products that are economically, environmentally, and socially beneficial. Biochar, with its high carbon content, will persist in the soil for hundreds of years and, as a carbon sequestration measure, can be offset by earning carbon credits. 

Compost Production with Biochar to Improve Compost Product Quality and Business Profit

Although compost and biochar production both utilize and recycle organic waste, there are several differences: compost production through aerobic fermentation is a biological process, while biochar production through pyrolysis is a thermal process. Furthermore, regarding raw materials, ideal compost production requires a moisture content of 60–70%, high nutrient content, and low lignin content, such as food waste and animal manure. Conversely, ideal biochar production requires a moisture content of 10–20% and a high lignin content, such as woody biomass.

Recent research suggests that adding biochar to the composting process accelerates composting, reduces greenhouse gas emissions such as methane (CH4) and nitrous oxide (N2O), reduces ammonia (NH3) loss, increases aeration and reduces compost density, and reduces odor. The biochar itself is not damaged or decomposed during the composting process but enriches it with various nutrients.

To achieve optimal results, the biochar dosage must be appropriate to the amount of organic matter used in the compost. Using too much biochar will disrupt the composting biodegradation process, and using too little biochar will diminish the positive effects mentioned above. With the appropriate dosage, biochar can accelerate the composting process. This is because it increases the homogeneity and structure of the mixture and stimulates microbial activity in the composting process.

This increased microbial activity will increase the temperature and speed up the composting process. Several studies have shown that adding 5% to 10% of the biochar volume at the start of composting can speed up the composting process by 20%. While the average compost production time is 2 months (9 weeks), adding biochar at the above dosage can speed up the composting process by 20%, or approximately 1.6 months (7 weeks). With the shorter production time and better compost quality, the added biochar can lead to a higher selling price, potentially equivalent to premium compost. This can offset the cost of adding biochar to the compost production process.

The pores in biochar reduce the bulk density of the compost and aid aeration during composting. For nitrogen-rich compost materials such as livestock manure, adding biochar can reduce N loss during composting, particularly NH3. The unpleasant odor is caused by the release of NH3 during composting, and for this reason, many composting facility developments are rejected by local residents. In a study, adding 20% ​​biochar (mass basis) to poultry litter reduced NH3 concentrations in gas emissions by 64% and N loss by 52% without negatively impacting the composting process.

When used, compost decomposes, with nutrients absorbed by plants, while biochar remains in the soil for centuries. This makes biochar a long-term solution for improving soil quality. Using biochar in compost offers both short-term and long-term benefits. The short-term benefit is as an organic fertilizer, while the long-term benefit is improving or stabilizing soil quality and sequestering carbon. CO2 absorbed through photosynthesis becomes biomass, or organic matter, as the raw material for biochar, and the carbon in biochar remains stable for hundreds of years, and is not released into the atmosphere during this time.

There is no data yet showing the calculated amount of compost production in Indonesia per year. However, the potential for compost production from domestic organic waste is very large, reaching around 60% of the total national waste generation which reaches more than 60 million tons per year or more than 36 million tons of organic waste as raw material for compost. There are a number of parties carrying out compost production in various regions in Indonesia, both government and private parties who contribute to compost production, with varying production capacities. With the very abundant organic raw materials (more than 36 million tons/year), the production of biochar-enriched compost can be carried out so as to maximize the quality of compost and other benefits.

This can be achieved by building a biochar production unit or installing a pyrolysis unit at the organic waste source. Organic waste materials that are less suitable for composting can be used for biochar production. Several companies are already planning to do this. Read the related article here. 

The Importance of SRF (Slow Release Fertilizer) With Biochar in Palm Oil Plantations

Biochar is not a fertilizer so even the nutrient content in biochar can be ignored. Even though there are a number of biochars that contain certain nutrients, this is a special matter and really depends on the raw materials used. Biochar is a soil amendment that functions to improve soil properties such as soil structure including increasing soil porosity/soil friability so that roots can penetrate deeper, soil aeration, water availability, shortening the age of harvest, inhibiting the development of plant pests and retaining nutrients and reducing soil acidity. Compared to other soil amendments which have weaknesses, including the need for large and continuous amounts because they decompose quickly, have the potential to negatively affect the climate, and introduce disease-causing microbes/pests, biochar has many advantages, including the volume required is not large enough, not continuous and able to survive in the soil (helps conserve carbon in the soil) is not decomposed for hundreds or even thousands of years. The above makes biochar can function to improve soil fertility and climate solutions (carbon sequestration / carbon sink) or an action to increase organic matter on agricultural land or plantations and mitigate the effects of climate change. 

Even so, biochar can be used to make fertilizer, namely slow release fertilizer (SRF). SRF is a fertilizer whose release is regulated to provide maximum growth effect or SRF is designed or modified fertilizer for controlled fertilization according to plant needs so as to provide increased use efficiency and at the same time increase yield or harvest. This is motivated by the low efficiency of fertilization so that even more is wasted than is utilized or low NUE (nutrient use efficiency). The function of biochar in SRF is as a slow release agent in the fertilizer because it has a porous structure. In making SRF, several methods can be used, including increasing the size (granulation, pellets, etc.), smoothing the surface of the fertilizer, mixing it with other materials that are difficult to dissolve (slow-release agent) and covering the fertilizer with certain materials so that the release of the fertilizer becomes slow (coating). The use of SRF is becoming popular to save fertilizer consumption, increase yields and minimize environmental pollution. 

Soil fertility is a complex trait or condition that must be kept optimal, especially regarding this fertilization. The component of soil fertility itself includes a number of things, namely the depth of the soil solum, soil structure, nutrient content, storage capacity, humus content, number and activity of soil microorganisms, and the content of toxic elements. Productive soils with high soil fertility, both naturally and/or due to human actions, are mainly due to the following characteristics: nutrients in the soil are mobile and easy to obtain, the ability of the soil to convert fertilizer into easily available forms, the ability of the soil to store nutrients dissolved in groundwater from the leaching process, the ability of the soil to provide a natural balance of nutrient supplies for plants, the ability of the soil to store and provide water for plants, the ability to maintain good soil aeration to ensure the availability of oxygen for roots, and the ability of the soil to bind (fix) nutrients and convert them into forms available to plants. Soil fertility must guarantee high, consistent and sustainable production.  

An understanding of the nutrient composition of fertilizer and its release mechanism will help make strategic plans to slow down the release of the fertilizer at a certain level. Compared to conventional fertilizers slow release fertilizer (SRF) has a very slow release speed which can be tens of times slower so that fertilization efficiency increases significantly. It is estimated that more than 50% of fertilizer is wasted due to various reasons including evaporation, immobilization in the soil and leaching due to water, for example due to rain or irrigation. This inefficiency of fertilization is not only detrimental from an economic aspect as well as the environment, namely making the soil acidic, killing soil microbes, and water-soluble fertilizers that can poison water that may be consumed by humans and animals.

Currently, developing countries use more than 60 million tons of fertilizer per year, while according to the Food Agriculture Organization (FAO) world fertilizer consumption reached 190.4 million tons in 2015. With this low level of efficiency, can be imagined how much fertilizer is wasted useless and only pollute the environment. Regarding SRF, the dose of biochar use must also be measured properly because the use of biochar that exceeds the dose will be useless. This is due to the hydrophobic nature of biochar, so that the excess dose does not or only a little can release the fertilizer slowly.

A number of parameters to be observed for administering biochar as SRF are the amount of FFB (fresh fruit bunch) production and its quality (yield of CPO, and its FFA content), continuity of fruiting throughout the year, and the level of uniformity of fruit maturity in one bunch. And it turns out that the use of biochar gave significant positive results, namely FFB production increased by more than 20%, fruit maturity uniformity was almost 100%, CPO yield was more than 25%, and FFA was only 2-5%. With the high production of FFB and the yield of CPO, the intensification of palm oil plantations should have been carried out rather than the extensification that was suspected of being an attempt to convert forest functions or deforestation which tends to receive negative attention from various parties. For more details, read here. There are still many things that can be optimized so that the palm oil industry is efficient, environmentally friendly and sustainable.

Tens of millions of tons of empty fruit bunches (EFB) at the palm oil mills are potential raw material for biochar production as well as tens of millions of hectares of oil palm plantations that can be used for biochar applications. In addition to overcoming the problem of biomass waste, biochar production also produces energy that can be used for the palm oil mill itself, in more detail, please read here. Compared to the production of fuel pellets from empty fruit bunches (EFB pellets) and the production of electricity from empty fruit bunches, the production of biochar has many advantages and advantages both economically and environmentally. In the end, modifying the fertilizer according to the use of the biochar will significantly increase the nutrient use efficiency (NUE) in the fertilizer, ensuring the effective circulation of nutrients and mitigating climate change with carbon sequestration.