Composting
| Technology | |
| |
| Technology details | |
| Name: | Composting |
| Category: | Conversion (Biochemical processes and technologies) |
| Feedstock: | Biowaste in general, Food waste, Garden and park waste (wood, leaves) |
| Product: | Compost |
Composting is a biological process in which micro-organisms convert organic matter such as plant and animal scraps into soil-like material called compost. Compost is easier to handle than manure and other raw organic materials, stores well and is odor-free. Composting is an ancient technology, practiced today at every scale from the backyard compost pile to large commercial operations.
Feedstock
Origin and composition
Composts can be made from most organic by-products. Common feedstocks are poultry, hog and cattle manures, food processing wastes, sewage sludge, municipal leaves, brush and grass clippings, sawdust, and other by-products of wood processing.
Ideally, several raw materials should be mixed together to create the "ideal" range of conditions, which are as follows:
| Condition | Ideal |
|---|---|
| C:N ratios of combined feedstocks | 25-35:1 |
| Moisture content | 45-60 wt.% |
| Available oxygen concentration | >10% or more |
| Feedstock particle size | Variable |
| pH | 6.5-8.0 |
| temperature | 54-60°C |
Pre-treatment
The pre-treatment usually starts with a sizing activity by chipping the feedstock and subsequently the necessary structural material is mixed in. The purpose of the structural material is to prevent the organic material from caking together. The feedstock mixture is also stripped of metals by means of an electromagnet. In preparation for intensive ripening, a homogeneous airy material is obtained.
Process
Composting occurs through the activity of micro-organisms naturally found in soils. Under natural conditions, earthworms, nematodes and soil insects do most of the initial mechanical breakdown of organic materials into smaller particles. Under controlled conditions, composters break down large particles through grinding or chopping. Once optimal physical conditions are established, soil bacteria, fungi, actinomycetes and protozoa colonize the organic material and initiate the composting process. These mesophilic organisms function best at warm temperatures (10-45°C). As temperatures in the compost pile increase, thermophiles (i.e., micro-organisms that thrive at temperatures above 45°C) take over. In the active "thermophilic" phase, temperatures of 54-65°C are reached which is high enough to kill pathogens and weed seeds and to break down phytotoxic compounds (i.e., organic compounds toxic to plants). After the active composting phase, temperatures gradually decline to around 37°C. The mesophiles recolonize the pile and the compost enters the "curing phase". During curing, organic materials continue to decompose and are converted to biologically stable humic substances (i.e., the mature or finished compost). There is no clear defined time for curing. Common practices in commercial composting operations range from one to four months.
Product
The final product is a valuable soil resource named compost. Compost can replace materials like peat and topsoil as seed starters, container mixes, soil amendments, mulches and natural fertilizers.
Post-treatment
In post treatment, the compost is screened at small sizes (up to 12 mm) and any remaining impurities are removed. The coarse fraction is reused in composting as a structural material.
Technology providers
| Company name | Country | Technology category | Technology name | TRL | Capacity [kg/h] | Processable mass [kg] | Feedstock: Food waste | Feedstock: Garden & park waste |
|---|---|---|---|---|---|---|---|---|
| Company 1 | [Country HQ location] | [Technology category (if different sub-categories are defined this has to be specified here, the available categories can be found on each technology page under the chapter Process and technologies)] | [Technology name (the "branded name" or the usual naming from company side)] | [4-9] | [numeric value] | ● | ● | |
| Company 2 | [Country HQ location] | [(if different sub-categories are defined this has to be specified here, the available categories can be found on each technology page under the chapter Process and technologies)] | [Technology name (the "branded name" or the usual naming from company side)] | [4-9] | [numeric value] | ● | ● |
Attero
Attero is a Dutch industrial scale waste processing company. It has a long history in processing the organic fraction of municipal solid waste (OFMSW), which are further processes at various locations. At first, the OFMSW is digested after which the resulting solid fraction will be composted togther with e.g., twigs. Subsequently, any contaminating component like glas or plastics are removed from the compost using various techniques. The various fractions within the compost are sifted for different applications.
| General information | |||
| Company: | Attero |
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| Country: | The Netherlands | ||
| Contact: | |||
| Webpage: | https://www.attero.nl/ | ||
| Technology and process details | |||
| Technology name: | Technology category: | Conversion (Biochemical processes and technologies) | |
| TRL: | 9 | Capacity: | kg·h-1 |
| Microorganism: | Processable mass: | 300.000.000 kg | |
| Other: | |||
| Feedstock and product details | |||
| Feedstock: | OFMSW | Product: | Soil amendment, biofuel |
Open access pilot and demo facility providers
Here we make the link to the Europe-wide network & database of open access multipurpose pilot and demo infrastructures for the European bio-economy.
Unfortunately the Pilots4U database doesn't contain shared facilities for the technology of composting. There is, however, a selection for anaerobic digestion: Pilots4U Database
Patents
Currently no patents have been identified.