The importance of processing organic waste
The importance to process organic waste is often neglected due to the assumption that organic waste will degrade without assistance and is safe to the environment. It’s true that organic waste will degrade by themselves, however, this process can be harmful to the environment and the health of the surrounding people if it occurs in a large volume. Organic waste in landfills will decay through an anaerobic process that produces methane, which is a greenhouse gas that can cause a global impact. If compared with carbon dioxide, methane has 30 times the capacity to absorb heat, hence can be more harmful if available in high concentration (Science Daily, 2014).
Other than its environmental impacts, organic waste in landfills can also harm the health of people around the landfill. With high methane concentration, oxygen inhalation may decrease and could result in asphyxiate (EPA Victoria, 2012). Furthermore, other harmful gasses that are produced, such as hydrogen sulfide, have the potential to cause respiration diseases (Science Daily, 2016).
For the above reasons, it is particularly important to process organic waste properly to prevent them from ending up in landfills and releasing harmful gasses. Vermicomposting is one of several techniques, such as biopores, biogas conversion and BSF (black soldier flies) technique, that processes organic waste. This technique converts organic waste into compost through the intermediary of worms. Vermicomposting is very effective and beneficial, because not only it reduces the amount of organic waste ending up in landfill, vermicomposting can also produce nutritious compost for private gardens or to be sold as a business.
What is vermicomposting?
The basic process of vermicomposting is very simple. Organic waste, such as fruit peels, vegetable scrap and even non-organic waste such as used papers, are consumed by worms to be processed in their body to be excreted as casting. This casting is what becomes compost that contains important nutritions for plant growth, such as magnesium, phosphorus and potassium. This is a basic decomposing process, where an organic material is converted into non-organic material. The difference with decomposition in landfill is that worms that are used in vermicomposting goes through aerobic process instead of anaerobic process, thus do not produce methane as a byproduct and reduce the amount of released greenhouse gas. Furthermore, the worms produce nutritional compost, which returns organic element back into the soil as nutrients for plant growth.
The types of worm for vermicomposting
There are two types of earthworms that are important to be considered when determining worms for vermicomposting, which are the burrowing and non-burrowing worms. The type of worm that is non-burrowing is the most effective type for vermicomposting because they tend to consume surface organic materials instead of the soil underneath. In contrary, burrowing worms are tend to be underneath the soil, hence less likely to consume organic materials on the surface. Eisenia foetida and Eisenia eugeniae are worm species that are known to be efficient in producing compost (Zafar from Bio Energy Consult, 2018).
The nutritions inside the produced compost depend on the type of organic waste that are processed and the type of worm that processes them. Pattnaik and Reddy (2010) from Applied and Environmental Soil Science journal found that Eisenia eugeniae produces compost with more nitrogen, phosphorus, potassium and magnesium than the compost that are produced by Eisenia foetida. Moreover, the C/N ratio inside the compost also need to be considered because it influence the availability of nutrients to the plant. Both species of earthworms that are discussed can produce compost with ideal C/N ratio, which is 20:1.
The types of organic waste for vermicomposting
There are certain types of organic waste that are more efficient in producing compost. Plant based organic waste, such as fruit peels and vegetable scrap are commonly more suitable to be processed through vermicomposting. However, fruits that are too acidic, such as lemons and garlic, is an exception because it could harm the worm. Furthermore, animal based organic waste, such as meat, dungs and dairy products are often not effective to be processed through vermicomposting because they release odour and attract pests. Below are some types of organic waste that can be processed through vermicomposting and that are not suggested (Food Print):
|Can be processed through vermicomposting||Not recommended|
|Vegetable and fruit scrap (peels, seed, stem, fruit, etc)||Lemon, lime, orange (too acidic)|
|Egg shell||Onion, garlic (too acidic)|
|Seaweed||Meat, fat, bones (attract pests)|
|Seashells||Stickers (e.g. on fruits or envelopes)|
|old clothes (tshirt, socks, etc)||Bread, cakes, crackers, yeast containing food|
|Used paper||Salt, pepper, white pepper, etc.|
|Tea||Dairy products (milk, cheese, etc)|
|Dead or dried plants (without pesticides)||Animal dung|
|Natural wood||Diseased plant|
|Hair and feathers||Treated wood|
From the above list, the types of organic waste that are not recommended to be vermicomposted may be able to be processed through other techniques, such as decomposition using BSF (black soldier flies). Further information about BSF can be obtained through this link: https://waste4change.com/blog/black-soldier-flies-bsf-great-business-opportunity-and-a-perfect-solution-to-organic-waste-problem/2/.
The steps in processing organic waste through vermicomposting
Below are the equipments and materials that are required to start vermicomposting (Associate Students of the University of California):
Equipment & Materials
- Worm bin.
- Newspaper, cardboard, coir or dried plants for the bedding inside the bin as a carbon source, maintain airflow and absorber of excessive moist.
- Organic waste.
- Red wiggler earthworms.
- Cover the base of the bin with bedding (newspaper, cardboard, coir or dried plant). Don’t keep it too tight to allow airflow.
- Insert organic waste into the bin in small amount to allow the worms to adapt in the new environment before being provided with abundant food source.
- Add a layer of bedding (newspaper, cardboard, coir or dried plant) on top of the organic waste.
- Set aside the bin for one or two days to allow the waste to decay and to allow the moisture to spread evenly across the bin before placing the worms.
- After one or two days, remove the top bedding layer and insert the worms. Place back the bedding over the new worms.
- Cover the bin and place it where it does not get exposed to direct sunlight.
Let’s produce compost using your own organic waste!
With a process that is relatively easy using simple equipments, vermicomposting is very efficient in reducing the negative environmental impacts, as well as human health impacts that arise from organic waste that ends up in the landfill. Furthermore, this technique can be applied in multiple scales, hence households and even businesses can implement vermicomposting. Many might doubt this technique because of the assumption that it causes odour and is difficult to implement. However, with the right type of organic waste and the right preparation of the worm bin, this technique does not produce any bad odour at all! Moreover, the simple equipments will not disturb the aesthetic of the space where it is placed. There really is no reason not to implement this technique for you who are interested. If this technique is not suitable with your environment or the available resource, there are other techniques that can be considered, such as biopores and BSF (black soldier flies) technique (see https://bit.ly/2CDCi7v). Further information about vermicomposting can be obtained through the following list of references.