Eco knowledge

Taiwan receives on average 2,510 mm of rainfall every year, 2.6 times the world average. Compared with the rainfall of 180 countries in the climate data published by the United Nations’ Food and Agriculture Organization (FAO) in 2014, Taiwan ranked 13th. In other words, we have abundant rainfall.

Yet no matter how abundant rainfall is, Taiwan faces a number of challenges to keeping its water tanks full. Our densely populated country has an uneven rainfall distribution, as around 80% of the annual rainfall occurs mostly during typhoon season, between May and October, resulting in a disparity of water levels in the wet and dry seasons. Moreover, the geographical features of Taiwan – high mountains, short rivers, and high velocity water courses – cause rainwater to flow into the sea quickly, making it even more difficult to collect and utilize water resources. Together with the huge difference in humidity between wet and dry seasons, as well as the unequal distribution in regional precipitation, Taiwan faces difficulties in water storage and allocation.

Other than that, low effective water storage capacity caused by reservoir sedimentation, wear and tear on water mains, pipe leakage due to road work, and the high numbers of heavy vehicles, all contribute to the problem of water shortage in Taiwan.

According to statistical data, an average person in the city uses 200 to 400 liters of water a day for showering, flushing the toilet, washing clothes, cleaning dishes, and watering plants. Wastewater generated by these activities will end up in the same place: the water treatment plant.

Not surprisingly, water is the main component (99%) of sewage. Others include manure, chemicals, and small substances. It is the main duty of treatment plants to remove these impurities before discharging the effluent into the sea through underground drainage. Sludge filtered out from the sewage will undergo anaerobic digestion in the settling basin. During this process, microorganisms will break down biodegradable materials, releasing methane, a gas that can be used to generate electricity. Even residue is not wasted! Rich in nutrients, it can be turned into organic soil for growing plants.

Bioenergy, or biomass energy, is a renewable energy source derived from biomass. It is an umbrella term for any organic material generated by living organisms, such as crops, biogas, general waste, and general industrial waste. Taiwan has a long history of agriculture, and is therefore well-equipped with the necessary technology to grow energy crops. In other words, we have the ability to produce the raw materials necessary for bioenergy. Biomass can be used as an alternative energy source and can produce a wide array of energy products, such as biomass alcohol, biodiesel, biogas, syngas, and densified refuse derived fuel (RDF-5).