Treating wastewater with plants, animals, and bacteria

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:Time: Pickton, in the province of Prince Edward Island in Canada, plans to invest 16 million dollars in building a state-of-the-art wastewater treatment plant known as the “Living Machine”. Its feature lies in using three living organisms—plants, animals, and bacteria—to treat wastewater simultaneously. Compared to conventional methods, its advantages are reduced sludge production, lower levels of toxic substances, and improved water quality of the wastewater. Conventional methods utilize only bacteria, a single living organism; they can also be considered part of advanced methods. This innovative technology was invented by Canadian scientist John Todd and has been recognized by the United Nations. This person was also listed by the Massachusetts Institute of Technology in the United States as one of the 35 greatest inventors of the 20th century. 　　How does Living Machine work? This system is essentially an imitation of natural processes, that is, the recycling of waste in wetlands such as swamps, ponds, and riverbanks. Since plants use waste as fertilizer, and many small animals feed on waste, both plants and animals are included in this artificial ecosystem. And why would a sewage treatment plant need to be built in a greenhouse? Since Canada is located in North America and experiences many cold periods, many organisms enter a state of dormancy at low temperatures, which slows down or even stops wastewater treatment processes. It is conceivable that building the factory in a greenhouse can solve the aforementioned problems. Moreover, using a mixture of local raw materials and those brought from the tropics can ensure that the processing process operates throughout the year. Once completed, this wastewater treatment plant will look and smell like a tropical greenhouse. It fully meets environmental requirements — “clean and green”. 　　New technologies reduce sludge production. One concern is the spread of sludge from wastewater treatment plants to farmland; however, the sludge produced by Living Machine is 30% less than that generated by conventional methods, as plants and small animals consume it. Moreover, plants can break down many types of synthetic organic compounds into smaller, non-toxic molecules, including 14 substances listed by the U.S. Environmental Protection Agency as major pollutants. 　　The U.S. Environmental Protection Agency believes that, from an aesthetic perspective, this wastewater treatment and recycling technology is unique in its ability to create a pleasing environment. Moreover, it can reliably meet the targets in terms of biochemical oxygen demand, total suspended solids, and total nitrogen content. It is a new technology that is ideal for treating urban and certain industrial wastewater. Currently, more than a dozen such wastewater treatment plants have been built around the world. 　　Low costs and operating expenses As for costs and operating expenses, its advantages become evident when compared with conventional methods. A conventional wastewater treatment plant is like a bottomless pit – chemicals, operation, maintenance, and sludge removal all require funding. It is also a place that people avoid approaching, let alone one from which revenue can be generated. But Living Machine is different; with its tropical greenhouse aroma and attractive appearance, it is not only a scenic sight in the city but also highly attractive to tourists who come to visit it. For example, the wastewater treatment plant built in Bear River Town, Fundy Bay, Nova Scotia, saw 8,000 visitors come to see it in the weeks before it was opened to the public; the town was unable to handle such a large influx of visitors and was forced to stop tours. Another example is South Berlington, Vermont, where 20,000 visitors come each year just to see the local wastewater treatment plant. If each person spends 100 dollars on food, accommodation, and gas, then these tourists’ total spending in that town for the entire year amounts to 2 million dollars. If visitors who come along the way are also taken into account, charging a few dollars per person still adds up to a significant amount. The Living Machine uses less chemicals and less energy, which means its operating costs are low. Moreover, it can also produce some agricultural products suitable for sale, such as flowers, certain types of fish, and plants for aquatic gardens, and so on. In summary, it is evident that such environmentally friendly technologies have great prospects for development.