During the Cold War, West Berlin was completely surrounded by East Germany. The Berlin Wall sealed the city...and its waste.
While food and supplies could be transported in from West Germany, there was no way West Berlin could send its waste all the way through East Germany and over the border to West Germany. It wasn't practical.
During the Cold War East and West Germany's border ran from near Lubeck in the north, down to midway between Dresden and Nurnberg. Berlin sat firmly inside East Germany. CIA World Factbook map
So as the US and its allies poured money into rebuilding West Germany, West Berlin's rubbish grew and grew.
Initially the city used landfills for rubbish. But eventually the landfills could take no more so an incinerator was built. This made little difference.
As well as rubbish, there was also the matter of sewage which caused problems for West Berlin's administrators. Solving this problem became one of the first waste agreements the Communist East had with the West.
Under the agreement, East Germany would handle West Berlin's sewage provided the West helped fix the East's leaking sewage plants. This included financing upgrades to the Nord plant , at Schonerlinde, on the outskirts of Berlin.
So US post-war reconstruction funds helped pay for Communist sewage plants.
While this sewer diplomacy bubbled along, East German soldiers continued to shoot at East Berliners trying to escape over the Berlin Wall into the West.
Thousands were trying to join separated families in wealthier West Berlin. This part of the city was booming and in 1971 had a population nearly double that of Communist East Berlin (2,083,987 compared to 1,087,982)
Nevertheless as West Berlin's affluence grew so too did it effluence. The city was being swamped by waste. So the Communist East once more entered into some Capitalist haggling over consumption and waste disposal. Thus despite hostilities and disagreements on most things, the two Cold War opponents were quite prepared to reach an agreement on one thing....waste.
In 1972, East Berlin agreed to take some of West Berlin' s rubbish. The arrangement worked well for the East. The West had lots of waste. And the East had ample space for landfills. After all Berlin was surrounded by Communist East German territory..
East Germany wanted the arrangement to continue. But more than that, it insisted West Berlin continue to tear down and construct buildings, toss out food, throw away furniture and create high levels of waste. Basically the West had to meet target levels of waste, otherwise the deal ended. Then in 1974, both agreed the waste relationship seemed to be working so a 20 year contract was signed.
Under this agreement apart from paying annual fees, the West Berlin public waste company Berliner Stadtreinigungsbetriebe (BSR) agreed to fund the modernisation of East Berlin's waste system.
West Berlin had no alternative but to accept the conditions. It was a costly agreement.
Throwing out waste became an expensive luxury. So West Berliners and the BSR were determined to reduce the burden of waste disposal. Although consumption increased, their waste did not exceed the East's targets. Thus they were not penalised with even higher costs.
The West Berliners did this by recycling everything they could. Residents separated metals, glass, paper, timber and kitchen waste. Incineration was expanded. More importantly, investments were made in new waste treatment methods.This new technology placed West Germans at the forefront of waste recovery and treatment technology.
Berlin: The Spatial Structure of a Divided City. Elkins, T.H; Hofmeister; Methuen & Co, New York; 1988
http://www.stadtentwicklung.berlin.de/umwelt/umweltatlas/ed110_06.htm Senate Department for Urban Development, Berlin