Plastic bottle recycling machine. Image: Rokas Tenys Shutterstock
One way to reduce some environmental problems is to use the by-products as raw material for other economic activities. Here are four alternatives, ranging from plastic waste to cockroaches.
Methane gas for buses in Karachi.
The Green Climate Fund and the Asian Development Bank are financing a zero-emission bus network. They feed on methane from cow dung.
The new bus system will start operating in 2020 and will serve 320,000 passengers a day. It is expected to reduce emissions by 2.6 million tons of carbon dioxide (CO2) equivalent over 30 years.
The program will be implemented over four years, until reaching a fleet of 200 hybrid buses.
The project will prevent approximately 3,200 tons of cow manure from ending up in the ocean. With the project, they will be converted into energy and fertilizer in a biogas plant. It will save more than 50,000 gallons of fresh water used to clean up waste in the bay.
Cockroaches to remove kitchen waste.
Chinese cities are in full growth. This results in the generation of an avalanche of food waste that cannot be contained in landfills.
The government has opted for cockroaches to solve the problem; the insects can then be used to feed livestock or to make medicine and beauty treatments.
In Jinan City, one billion cockroaches are fed 50 tons of kitchen waste a day. The residues are transported through pipes for food in the insect farm.
The proposal has gained momentum given the ban on feeding pigs with food waste. The measure was taken to prevent outbreaks of swine fever. Cockroaches are a good source of protein, they are even capable of healing oral and peptic ulcers, as well as skin wounds.
Researchers are studying the use of cockroach extracts in beauty treatments, diet pills, and hair loss treatment.
Cockroaches have an average lifespan of six months. When they die they are washed and dried. Finally they are sent to a tank that allows to extract their nutrients.
Recycling of plastic waste.
In Surabaya, Indonesia, you can travel by subway and bus, leaving plastic bottles as a form of payment. The ticket for the bus costs 10 plastic cups or five plastic bottles. The intention is to facilitate the work of garbage collectors since the city generates almost 4,000 tons of plastic waste daily.
With the implementation of the program, a bus can collect up to 250 kilos of plastic bottles per day, which means 7.5 tons in a month. Once collected, labels and caps are removed from the bottles for auction.
The money obtained is used to make improvements to the bus lines and the creation of new green spaces.
In Germany they have a similar system.
Pellets as energy support.
In Copenhagen, the state energy company HOFOR is setting up a power plant to burn renewable wood pellets. The intention is to have an alternative energy support to wind energy.