PETpla.net Insider 05 / 2020

PACKAGING / PALLETISING PETplanet Insider Vol. 21 No. 05/20 www.petpla.net 17 Water supply in Mexico City Is safe drinking water possible without plastic? by Claudia Wörner, PR Agency yes or no Media and Kathya Santoyo Zarate, Editorial Director of “Global Energy & Global Industries” in Mexico One thing is clear: plastic waste in the environment is a problem. In many parts of the world plastics are needed. In Mexico City, for example, plastic bottles are important for supplying the population with clean drinking water. 8.9 million people live in Mexico City - a little more than in Austria or Switzerland. The entire conurbation even has over 21 million inhabitants. This makes Mexico City the world’s third largest megacity after Tokyo and Mumbai - and it faces an enormous challenge: supplying its inhabitants with drinking water. Fresh drinking water from plastic bottles Water flowing from the taps is often visibly contaminated by sedi- ments or colouration. If it is flowing at all, because the city’s water network is repeatedly disturbed. 18 per cent of the population officially live with a water supply system that functions only irregularly. Another source of water is the tankers known as “pipas”. But its quality is as unclear as its origin. The irregular supply has cre- ated a vicious circle. People collect the water in tinacos - canisters on the roofs - in case the water fails again. Because the water supply is so poor, the inhabitants of Mexico City consume between 250 l and 500 l of drinking water in plastic bottles every year, depending on estimates. It is the only safe source of drinking water for them. The people use it for personal consumption - even for cooking. Tap water, on the other hand, is only just used for household purposes and for washing. Energy recycling as the most sensible option So, plastic bottles in Mexico City are important for the well-being and health of the inhabitants. To prevent these plastic bottles from becom- ing an environmental problem, the waste must be properly disposed of and recycled. The best and easiest way to do this would be to collect and thermally recycle plastic waste. This energy recycling even has a double benefit: On the one hand, clean drink- ing water for the population. On the other hand, the energy contained in the plastic can be used to generate electricity and heat. Background of the water crisis Due to the geographical location of Mexico City, the procurement of water is a challenge. In the past, the metrop- olis was located in the middle of a salt- water lake; today the groundwater is pumped out. An earthquake in Novem- ber 1985 contributed significantly to the current situation. For well over 100 years, the water of the megacity has been pumped from deep wells. About 3,000 wells in the city area pump it up from depths of 400m. This causes the city’s ground to sink in. In 2014, satellite measurements by the Euro- pean Space Agency (ESA) showed that in large parts of the city area, the water will sink by 30cm per year. In some places it is even 50cm per year. As a result, new damage to the water systems is occurring time and again. Pipes break, wastewater seeps into drinking water pipes, gradients are reversed. Over 40 per cent of the water pumped is lost through leaks. In view of this situation, there is no improve- ment in sight despite all the efforts of the city administration. The strong earthquake of 19 November 1985 is considered to be an accelerator of the water shortages, and on the morning of that day, in addition to numerous buildings and roads, the underground water and sewage pipes were also severely damaged. Many households were left without water afterwards. In others, only a cloudy liquid flowed out of the pipes. The aversion to tap water spread among the inhabitants. In addition, shortly afterwards the city administration warned against using the water for cooking or drinking. Clean water from plastic bottles is therefore the only solution for the inhabitants of Mexico City. PACKAGING