VOLKAN DÜNDAR

Composting of Biodegradable Waste in Urban Areas

What is Compost?

Compost is a humus-like material produced when all organic matter left behind by living organisms is broken down and mineralized by microorganisms under suitable conditions.

Various composting methods can be applied depending on the characteristics of the organic materials, the local environment, and economic conditions.

The importance of composting in urban areas stems from the critical need to separate food waste from other waste at the source during waste recycling. If biodegradable food waste in household waste is not separated from other waste at the source, the waste it contaminates cannot be recycled, leading to massive amounts of waste being transported as trash and resulting in uncontrolled dumping.

Trash: can be defined as material found where it shouldn’t be.

Household food waste is actually not a problem—it’s a resource.

According to 2024 data, the daily amount of solid waste in Istanbul is 20,000 tons.

According to municipal data, 4,609,000 tons of waste were transported in 2024. This amounts to 12,592 tons of waste transported daily.

A garbage truck carries 13–15 tons of waste. A total of 1,000 truck trips were made daily to transport waste.

Waste travels 45 km on the Asian side and 90 km on the European side to reach disposal facilities.

The daily per capita waste amount is 1.1 kg.

56% of the waste consists of biodegradable organic waste.

Managing this amount of waste is impossible.

In addition to transportation costs, there are traffic problems, air pollution, large areas of land being contaminated, and residents living near landfills are suffering.

Yet all these problems stem from a flawed lifestyle.

The linear production-consumption paradigm of “take-make-dispose” is no longer compatible with life.

Changing this paradigm and transitioning to a lifestyle that incorporates the circular use of resources is actually very easy, inexpensive, efficient, and healthy.

If biodegradable organic waste is separated from other waste at the source and composted there, managing the remaining waste becomes much easier.

If bokashi compost is produced from biodegradable household food waste at the source, the volume of this waste decreases by 50%, and 30% bokashi leachate is produced. This liquid is a nutrient-rich liquid fertilizer containing beneficial microorganisms, minerals, and bioactive molecules, and it is very easy to transport, use, and store.

Bokashi Compost:

It ensures that organic waste is separated from other waste at the source and composted on-site without transportation.

It is the process of converting organic waste into a pickle-like substance through lactic fermentation with beneficial bacteria in a low-oxygen environment (0.5–2%), without unpleasant odors or flies and insects.

• It is very easy to use
• It is the cheapest composting method.
• It requires no energy expenditure
• The volume of waste is reduced by 50% at the end of the process, and Bokashi leachate, equivalent to 30% of the weight, is obtained from the bottom. This liquid is a very rich liquid fertilizer.
• It can be done on a small scale (at home) or on a large scale
• No foul odors are produced
• There is no loss of carbon, nitrogen, or sulfur
• It acts as a fertilizer that slowly dissolves in the soil
• Waste is composted where it is generated, eliminating the costs of collection, transportation, and storage. Those who make compost often turn to balcony gardening.
• It can be used alongside compost and vermicompost
• It can be used in Black Soldier Fly (BSF) larvae production
• It utilizes all types of kitchen waste
• In some municipalities in our country, bokashi bins are distributed to the public, and food waste is converted into bokashi compost.

The reason for failure in waste management is that the public cannot benefit from the recycling economy.

In Turkey, 90% of the population lives in urban areas; 80% of these live below the poverty line, and 30% of them live below the hunger threshold. All unemployment is concentrated in cities. 90% of food consumption occurs in cities. Depending on the type of food, 40–60% is wasted during its journey from farm to fork.

Although food is the most significant expense for low-income individuals, they can only afford the cheapest, least nutritious, and most heavily contaminated foods with agricultural pesticides.

Food waste, which is not a major issue in rural areas (it is consumed by domestic animals or turned into fertilizer), is one of the biggest problems in urban areas.

Using our own water and compost, we can produce part of our own food for free through balcony gardening without any external input costs.

Worm Composting:

• Worm composting is the biological oxidation of organic waste by worms and the microorganisms that work in harmony with them. The result is worm castings, a stable product rich in humus.
• It can be practiced on a very small scale at home as well as in large-scale operations.
• The resulting product is an exceptional soil conditioner and possesses unique properties that promote plant growth.

Balcony Gardening:

• 90% of people live in cities, and while 80% of them live below the poverty line, growing one’s own food is equivalent to printing one’s own money.
• In cities, a portion of food can be easily grown in raised beds or “wicking beds” on balconies, terraces, gardens, sidewalks, and in parks.

In our home, we’ve been using this system for 15 years to compost food scraps without sending them to the city’s waste collection system, and a significant portion of our vegetables are grown in our garden.