Applications of Biochar

Biochar is a carbon-rich, fine-grained residue which can be produced either by ancient techniques (such as covering burning biomass with soil and allowing it to smoulder) or state-of-the-art modern biomass pyrolysis processes. Combustion and decomposition of woody biomass and agricultural residues results in the emission of a large amount of carbon dioxide. Biochar can store this CO2 in the soil leading to reduction in GHGs emission and enhancement of soil fertility. Biochar holds the promise to tackle chronic human development issues like hunger and food insecurity, low agricultural productivity and soil depletion, deforestation and biodiversity loss, energy poverty, water pollution, air pollution and climate change. Let us have a close look at some of the most promising applications of biochar.

 

Use of biochar in animal farming

At present approx. 90% of the biochar used in Europe goes into animal farming. Different to its application to fields, a farmer will notice its effects within a few days. Whether used in feeding, litter or in slurry treatment, a farmer will quickly notice less smell. Used as a feed supplement, the incidence of diarrhoea rapidly decreases, feed intake is improved, allergies disappear, and the animals become calmer.

In Germany, researchers conducted a controlled experiment in a dairy that was experiencing a number of common health problems: reduced performance, movement disorder, fertility disorders, inflammation of the urinary bladder, viscous salivas, and diarrhoea. Animals were fed different combinations of charcoal, sauerkraut juice or humic acids over periods of 4 to 6 weeks.

Experimenters found that oral application of charcoal (from 200 to 400 g/day), sauerkraut juice and humic acids influenced the antibody levels to C. botulinum, indicating reduced gastrointestinal neurotoxin burden. They found that when the feed supplements were ended, antibody levels increased, indicating that regular feeding of charcoal and other supplements had a tonic effect on cow health.

Biochar as soil conditioner

In certain poor soils (mainly in the tropics), positive effects on soil fertility were seen when applying untreated biochar. These include the higher capacity of the soil to store water, aeration of the soil and the release of nutrients through raising the soil’s pH-value. In temperate climates, soils tend to have humus content of over 1.5%, meaning that such effects only play a secondary role.

Indeed, fresh biochar may adsorb nutrients in the soil, causing at least in the short and medium term – a negative effect on plant growth. These are the reasons why in temperate climates biochar should only be used when first loaded with nutrients and when the char surfaces have been activated through microbial oxidation.

The best method of loading nutrients is to co-compost the char. This involves adding 10–30% biochar (by volume) to the biomass to be composted. Co-composting improves both the biochar and the compost. The resulting compost can be used as a highly efficient substitute for peat in potting soil, greenhouses, nurseries and other special cultures.

Because biochar serves as a carrier for plant nutrients, it can produce organic carbon-based fertilizers by mixing biochar with such organic waste as wool, molasses, ash, slurry and pomace. These are at least as efficient as conventional fertilizers, and have the advantage of not having the well-known adverse effects on the ecosystem. Such fertilizers prevent the leaching of nutrients, a negative aspect of conventional fertilizers. The nutrients are available as and when the plants need them. Through the stimulation of microbial symbiosis, the plant takes up the nutrients stored in the porous carbon structure and on its surfaces.
A range of organic chemicals are produced during pyrolysis. Some of these remain stuck to the pores and surfaces of the biochar and may have a role in stimulating a plant’s internal immune system, thereby increasing its resistance to pathogens. The effect on plant defence mechanisms was mainly observed when using low temperature biochars (pyrolysed at 350° to 450°C). This potential use is, however, only just now being developed and still requires a lot of research effort.

Biochar as construction material

The two interesting properties of biochar are its extremely low thermal conductivity and its ability to absorb water up to 6 times its weight. These properties mean that biochar is just the right material for insulating buildings and regulating humidity. In combination with clay, but also with lime and cement mortar, biochar can be added to clay at a ratio of up to 50% and replace sand in lime and cement mortars. This creates indoor plasters with excellent insulation and breathing properties, able to maintain humidity levels in a room at 45–70% in both summer and winter. This in turn prevents not just dry air, which can lead to respiratory disorders and allergies, but also dampness and air condensing on the walls, which can lead to mould developing.

As per study by the Ithaka Institute’s biochar-plaster wine cellar and seminar rooms in the Ithaka Journal. Such biochar-mud plaster adsorbs smells and toxins, a property not just benefiting smokers. Biochar-mud plasters can improve working conditions in libraries, schools, warehouses, factories and agricultural buildings.

Biochar is an efficient adsorber of electromagnetic radiation, meaning that biochar-mud plaster can prevent “electrosmog”. Biochar can also be applied to the outside walls of a building by jet-spray technique mixing it with lime. Applied at thicknesses of up to 20 cm, it is a substitute for Styrofoam insulation. Houses insulated this way become carbon sinks, while at the same time having a more healthy indoor climate. Should such a house be demolished at a later date, the biochar-mud or biochar-lime plaster can be recycled as a valuable compost additive.

Biochar as decontaminant

As a soil additive for soil remediation – for use in particular on former mine-works, military bases and landfill sites.

Soil substrates – Highly adsorbing and effective for plantation soil substrates for use in cleaning wastewater; in particular urban wastewater contaminated by heavy metals.

A barrier preventing pesticides getting into surface water – berms around fields and ponds can be equipped with 30-50 cm deep barriers made of bio-char for filtering out pesticides.

Treating pond and lake water – bio-char is good for adsorbing pesticides and fertilizers, as well as for improving water aeration.

Use of biochar in wastewater treatment – Our Project

The biochar grounded to a particle size of less than 1.5 mm and surface area of 600 – 1000 m2/g. The figure below is the basic representation of production of bio-char for wastewater treatment.

We conducted a study for municipal wastewater which was obtained from a local municipal treatment plant. The municipal wastewater was tested for its physicochemical parameters including pH, chemical oxygen demand (COD), total suspended solids (TSS), total phosphates (TP) and total Kjeldahl nitrogen (TKN) using the APHA (2005) standard methods.

Bio filtration of the municipal wastewater with biochar acting as the bio adsorbent was allowed to take place over a 5 day period noting the changes in the wastewater parameters. The municipal wastewater and the treated effluent physicochemical.

The COD concentration in the municipal wastewater decreased by 90% upon treatment with bio-char. The decrease in the COD was attributed to the enhanced removal of bio contaminants as they were passed through the bio char due to the bio char’s adsorption properties as well as the high surface area of the bio char. An 89% reduction in the TSS was observed as the bio filtration process with bio char increased from one day to five days

The TKN concentration in the wastewater decreased by 64% upon treatment with bio char as a bio filter. The TP in the wastewater decreased by 78% as the bio filtration time with bio char increase. The wastewater pH changed from being alkaline to neutral during the treatment with bio char over the 5 day period

Use in Textiles

In Japan and China bamboo-based bio-chars are already being woven into textiles to gain better thermal and breathing properties and to reduce the development of odours through sweat. The same aim is pursued through the inclusion of bio-char in shoe soles and socks.

Waste Management in Food Processing Industry

Food processing industry around the world is making serious efforts to minimize by-products, compost organic waste, recycle processing and packaging materials, and save energy and water. The three R’s of waste management – Reduce, Reuse and Recycle – can help food manufacturers in reducing the amount of waste sent to landfill and reusing waste.

EPA’s Food Recovery Hierarchy

EPA’s Food Recovery Hierarchy is an excellent resource to follow for food processors and beverage producers as it provides the guidance to start a program that will provide the most benefits for the environment, society and the food manufacturer.

Notably, landfill is the least favored disposal option for waste generated in food and beverage producers worldwide. There are sustainable, effective and profitable waste management options including:

  • making animal feed,
  • composting to create nutrient-rich fertilizer,
  • anaerobic digestion to produce energy-rich biogas,
  • recycling/reusing waste for utilization by other industries,
  • feeding surplus food to needy people

Waste Management Options

Food manufacturers has a unique problem – excess product usually has a relatively short shelf life while most of the waste is organic in nature. Food waste created during the production process can be turned into animal feed and sold to goat farms, chicken farms etc. As far as WWTP sludge is concerned, top food manufacturers are recycling/reusing it through land application, anaerobic digestion and composting alternatives.

Organic waste at any food processing plant can be composted in a modern in-vessel composting and the resultant fertilizer can be used for in-house landscaping or sold as organic fertilizer as attractive prices.

Another plausible way of managing organic waste at the food manufacturing plant is to biologically degrade it in an anaerobic digester leading to the formation of energy-rich biogas and digestate. Biogas can be used as a heating fuel in the plant itself or converted into electricity by using a CHP unit while digestate can be used as a soil conditioner. Biogas can also be converted into biomethane or bio-CNG for its use as vehicle fuel.

Items such as cardboard, clean plastic, metal and paper are all commodities that can be sold to recyclers Lots of cardboard boxes are used by food manufacturers for supplies which can be broken down into flat pieces and sold to recyclers.

Cardboard boxes can also be reused to temporarily store chip packages before putting them into retail distribution boxes. Packaging can be separated in-house and recovered using “jet shredder” waste technologies which separate film, carton and foodstuffs, all of which can then be recycled separately.

Organizing a Zero-Landfill Program

How do you develop a plan to create a zero-landfill or zero waste program in food and beverage producing company? The best way to begin is to start at a small-level and doing what you can. Perfect those programs and set goals each year to improve. Creation of a core team is an essential step in order to explore different ways to reduce waste, energy and utilities.

Measuring different waste streams and setting a benchmark is the initial step in the zero-landfill program. Once the data has been collected, we should break these numbers down into categories, according to the EPA’s Food Recovery Challenge and identify the potential opportunities.

For example, inorganic materials can be categorized based on their end lives (reuse, recycle or landfill).  The food and beverage industry should perform a waste sort exercise (or dumpster dive) to identify its key streams.

Nestlé USA – A Case Study

In April 2015, Nestlé USA announced all 23 of its facilities were landfill free. As part of its sustainability effort, Nestlé USA is continually looking for new ways to reuse, recycle and recover energy, such as composting, recycling, energy production and the provision of safe products for animal feed, when disposing of manufacturing by-products.

Employees also work to minimize by-products and engage in recycling programs and partnerships with credible waste vendors that dispose of manufacturing by-products in line with Nestlé’s environmental sustainability guidelines and standards. All Nestlé facilities employ ISO 14001-certified environmental management systems to minimize their environmental impact.