Composting Science Basics

The process of reducing the amount of waste produced by a person or a society.

Using an item more than once, either for its original purpose or a new function.

The process of obtaining substances from waste (secondary raw materials) and using them as substitutes for primary raw materials.

The biochemical decomposition of organic substances found in waste, transforming them into a nutrient-rich soil amendment.

Technologies that aim to reduce the volume of waste and recover energy from it.

The proper disposition of discarded or discharged materials according to environmental regulations.

The end products of food processing industries that are not recycled or reused, discarded due to their low economic value.

A rich soil created through the composting process, excellent for gardening and horticultural plants.

The ideal temperature range for composting, where microorganisms thrive and rapidly break down organic matter.

The measurement of acidity or alkalinity, important for composting because microorganisms prefer a neutral pH.

The ratio of carbon to nitrogen in organic matter, crucial for efficient composting.

A thermal process that breaks down organic matter in the absence of enough oxygen, producing a gas rich in hydrogen and carbon monoxide.

The main components of gasification gas, used as fuel or for further chemical conversion.

A process that occurs during composting, where organic acids release and temporarily lower the pH.

A process that occurs during composting, where nitrogen compounds break down into ammonia, increasing alkalinity.

The final neutral pH value (7) that compost typically reaches at the end of composting.

The ideal pH for compost, where microorganisms thrive and decomposition occurs efficiently. A higher pH can inhibit microbial activity, while a lower pH can create an unpleasant odor.

The ratio of carbon to nitrogen in composting material, which ideally is less than 80:1. A higher ratio indicates less nitrogen, which is crucial for microbial activity.

Smaller particle size is beneficial for composting because it increases the surface area for microorganisms to work on, leading to faster decomposition and more heat generation. Think of a sandwich: the more you cut it, the more surface area is exposed!

Fresh air is crucial for composting because it provides oxygen for the aerobic microorganisms that decompose organic materials. Regular mixing helps to introduce oxygen, especially in the early stages of composting.

The space within the compost pile where air can circulate, supplying oxygen to the microorganisms. It is essential for proper aeration.

The ideal moisture content for composting, where microorganisms can thrive. Too high and the process slows down, too low and the microorganisms struggle.

The amount of heat generated by the composting process, which indicates the level of microbial activity. Higher temperatures speed up the decomposition process.

The activity of the microorganisms is crucial for composting, and this activity is affected by the moisture content, aeration, and particle size, as well as the pH and C/N ratio.

A thermal process that involves burning solid waste in an oxygen-rich environment at high temperatures (above 850°C), producing combustion gases, ash, and heat.

The main goal of incineration is to reduce the volume of waste while simultaneously recovering the energy contained within it.

The process of breaking down organic matter in the absence of oxygen using microorganisms, producing biogas (methane) and digestate.

A common application of biomethanation in treating wastewater sludge and solid organic waste, offering volume and mass reduction of input materials.

The net energy produced per ton of solid waste through incineration, which can be used for electricity generation and district heating.

The primary chemical reactions that occur during incineration, involving the breakdown of solid waste components like carbon, hydrogen, sulfur in the presence of oxygen.

The inorganic residue remaining after incineration, consisting of non-combustibles like minerals.

High-pressure steam produced in the fluidized bed boiler during incineration, used for energy generation in power plants.

A process that converts organic materials into gas, liquids, and solid char, producing a synthetic gas (syngas) containing hydrogen, carbon monoxide, and other gases.

In pyrolysis, volatile components of the organic material are converted into gases, liquids, and solid char.

The main products of pyrolysis are syngas (synthetic gas), char, and ash. Syngas is used for energy generation, char can be used as fuel or recycled, and ash is typically disposed of in a landfill.

The main reactions taking place during gasification are: * Conversion of solid fuels into gaseous products, like carbon monoxide and hydrogen. * Chemical reactions between the fuel and steam to produce more hydrogen. * Reactions that produce heat.

Gasification is similar to pyrolysis, but it involves the addition of air or oxygen, which allows for complete combustion and produces more energy.

The syngas produced during gasification is a valuable energy source that can be used to generate power, heat, or produce chemicals.

Waste is often treated through gasification or pyrolysis to recover energy and produce recyclable materials. For example, gasification can convert municipal solid waste into syngas.

The main advantage of gasification and pyrolysis is the conversion of waste materials into energy and valuable byproducts, reducing reliance on fossil fuels and landfills.