Which US city has the most garbage?

Sustainable cities: Turn garbage into gold

The Russian capital Moscow has a garbage problem. In order to dispose of the garbage of 12.4 million inhabitants, a new landfill is to be built in Arkhangelsk, 1200 kilometers away, in order to store the capital's garbage there for an indefinite period. When the excavators came, environmental activists and residents in the village of Schijes took to the streets to block the access routes to the planned landfill.

Moscow isn't the only city that would like to make the garbage go away. According to UN Habitat, the United Nations Housing and Settlement Program, we produce two billion tons of waste worldwide every year. By 2050 it will be four billion tons. 80 percent of this comes from cities in which three quarters of all goods are produced. Very few cities have their garbage problem under control.

Worldwide, more than a third of all waste ends up unsorted in landfills, according to the World Bank report "What a Waste 2.0". The consequences: environmental pollution, contamination of drinking water and damage to health.

The millions of people who make a living from collecting rubbish are the first to get sick. But she and the residents at the landfill are not the only victims. It pollutes the air when they burn electronic waste in the open air to get to the recyclable metals.

In the Agbogbloshie district of Accra, everything is contaminated with electronic waste: the water, the air and the soil.

Unsorted waste - for example from hospitals or slaughterhouses - is infected with germs that also flow into the groundwater and bodies of water. Plastic packaging such as plastic bags or PET bottles clog sewage systems and reach the oceans via rivers - and ultimately end up in the fish on the plate.

Raw materials from garbage

According to UN Habitat, there are a lot of raw materials in the garbage if they are properly separated and appropriately reused. Organic waste can be used as compost and in biogas plants and thus used for energy generation and soil improvement. Many metals are already so expensive that recycling is also economically viable. In an urban mining system, valuable resources such as gold, silver, copper or aluminum can be extracted - but only if the mixed waste is properly collected and separated.

Everything that can be recycled saves resources and raw materials.

Energy from garbage

Cities are energy guzzlers. Factories, households and traffic consume vast amounts of it: for production, for heating or cooling apartments, for light, for mobility. Here, too, savings and recycling can save fossil fuels. For example, through district heating networks that use the waste heat from industrial and waste incineration plants. Or through biomass plants in which compostable household waste, wood and straw are processed into biogas, electricity or heat.

Biomass for energy generation can also be used on a large scale

Better insulation of the building lowers energy costs, regardless of whether it is heated or cooled. In traffic, well-developed public transport networks and the promotion of cyclists and pedestrians can not only save energy, but also improve the quality of life in cities.

With such measures, the Danish capital Copenhagen wants to become CO2-neutral by 2025 - and seems to be sticking to the schedule. For hot water preparation, the energy obtained from garbage and waste products is supplemented by wind energy and solar thermal energy. An additional well-developed cycle path system as well as parking and charging areas for electric cars should make urban mobility as CO2-free as possible.

Industrial water from wastewater

Wastewater and cooling water from industrial production, rainwater from the sewer system and wastewater from households in a city: around the world, around 90 percent of wastewater flows unfiltered into rivers and seas or seeps into the ground.

Many cities are already struggling with water scarcity or lack of water. A lot of water could be reused if it were only treated technically - for agriculture, for flushing toilets, for heat generation, even for drinking water.

When it comes to water treatment, Singapore is exemplary. The city is considered to be one of the richest, cleanest and safest cities in the world. But it has - except for rain - no fresh water supplies of its own. The city has to import almost a third of its drinking water consumption from neighboring Malaysia.

Singapore uses rainwater and high-tech recycling to meet its water needs.

It rains a lot in Singapore - and the city-state has built sewers and 17 artificial lakes to catch and store the precious water. This means that Singapore covers almost a third of its water needs.

40 percent of the water in Singapore is now generated by the "NEWater" treatment project. The treated wastewater is usually not used as drinking water, although it meets the requirements of the World Health Organization (WHO), but is used for industrial production and cooling. But when the drinking water in the reservoirs becomes scarce due to a lack of precipitation, up to five percent of the treated water can also be added there.

Climate killer concrete

Cities are growing incessantly, especially in developing and emerging countries. Around four billion people already live in cities today, and by 2050 it should be over six billion. In order to accommodate all the people, workplaces and production facilities, one building material in particular is used: concrete. Concrete is malleable, flexible and relatively inexpensive. It consists of sand, gravel, water and the binding agent cement - concrete would be the perfect building material for booming cities if it weren't for the carbon footprint.

Cement is a climate killer and causes more CO2 than all air traffic. (Photo: Dubai)

Because cement production is energy and CO2-intensive and causes far more climate-damaging CO2 than global air traffic. If the cement industry were a country, it would be at the top of the list of CO2 emitters as the third largest greenhouse gas emitter, after China and the USA. The UN Habitat program assumes that the demand for concrete will increase by 2050, especially in the rapidly growing cities in Asia and Africa. How much depends above all on whether it is possible to use alternative building materials or to make cement more climate-friendly.

The good news: the new technologies are already there. They are not only more environmentally friendly but also cheaper than concrete, can often be combined with local raw materials and can be used worldwide.

So did Dr. Gnanli Landrou from the Professorship for Sustainable Building at the ETH Zurich in Switzerland, developed a cement-free building material, mainly based on clay. Its earth concrete is 90 percent more environmentally friendly and 60 percent cheaper than normal concrete.

Other materials science projects reduce the cement content in building materials and replace it with rubble, wood or waste products from agriculture. At the University of Lagos, researchers have even used the ashes from cassava pods as a cement substitute. The plant bowls are in abundance wherever cassava is a staple food.

Soon more plastic than fish in the sea

Rivers, seas and soils have already degenerated into landfills. If the trend continues like this, there will be more plastic waste than fish in the world's oceans by 2050, according to a study by the Ellen MacArthur Foundation.

But not only the amount, but also the sometimes toxic composition of the plastics give cause for concern, according to the study, which primarily examines the consequential damage to plastic packaging. 95 percent of the plastic packaging is intended for single use. Almost a third of it later ends up unfiltered in the environment, where it takes centuries to decompose.

According to the study, not only could costs be saved, but income could also be generated if the plastic were professionally recycled. Only 14 percent of plastic waste is collected for recycling, with so-called "thermal recovery" being the top priority. This is incineration in waste plants to generate energy.

Real recycling into high-quality or equivalent products can only take place if the plastic waste is sorted according to type and does not consist of several different plastics. With the study, the foundation wants to stimulate better recycling of plastic waste: With a circular economy in which raw materials are recycled again into products of equal value or at least recycled that replaces fossil fuels. Meanwhile, according to the Ellen MacArthur Foundation, more than 150 companies have joined the "New Plastics Economy Global Commitment" and want to make their plastic packaging recyclable.

Avoid instead of utilizing

But better than any recycling is avoidance, according to the foundation's study. No single-use packaging, no plastic mixtures that cannot be recycled and, above all, no plastics that are not collected and ultimately end up in the environment.

This applies to the entire amount of waste. Around a third of all food produced is lost. In the countryside due to the lack of storage and transport options, but also in the cities tons of food end up in the garbage every day. Food that was left on the plates, was too crooked or unsightly to sell - or was simply too much bought. Here, too, the "less is more" principle applies: for the environment, for the climate, for the consumption of resources and for health.

At least with household waste, everyone can start with themselves: do without packaging, buy durable and repairable products and throw less in the bin.