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This post was last edited by yinkuilin6868 on 2016-6-14 at 18:07. Germany’s land area is 350,000 square kilometers; its population is 82 million. There are only three cities with a population of over one million: Berlin (3.3 million), Hamburg (1.7 million), and Munich (1.28 million). Over 70% of the population lives in towns with a population of less than 100,000, with most residing in villages and towns with a population of 1,000–2,000 people. ““Environment”: If German cities are like the countryside, then Germany’s countryside is comparable to cities. Undoubtedly, the green coverage in rural areas is higher than that in cities, and the infrastructure is by no means inferior: there is everything needed such as water supply and sewage systems, electricity, communication facilities, and transportation. “ \"Waste sorting\" – if we ourselves can’t take care of our living environment, how can we expect others to do so? The trash bin in the kitchen of German farmer Ella’s home is already quite astonishing. Daily biological waste is collected through specialized biological trash bins, chopped up, and combined with the black water collected by vacuum pipeline systems to be sent to the technical treatment center in the residential area. A mixture of the two is first purified at high temperatures, and then introduced into a fermentation reactor operating at 30-40 degrees Celsius. After aerobic treatment and stabilization, a liquid substance rich in high concentrations of nutrients remains. These liquids will be stored and used for the landscaping maintenance of residential areas or sold to nearby agricultural cooperatives. The organization distributes it to its members for agricultural use and stores it in seasonal storage facilities. The reuse of nutrients not only allows the nutrient-rich waste generated in human settlements to enter the natural material cycle in an ecologically sustainable manner, but also replaces the energy-intensive production of chemical fertilizers to contribute to energy conservation. “ After entering the 21st century, the traditional centralized treatment methods have been replaced by new decentralized wastewater treatment approaches. Before the 1990s, industrialized centralized treatment methods were used for rural wastewater in Germany, whereby wastewater was pumped through drainage pipes to a wastewater treatment plant for centralized processing. However, this approach not only resulted in high costs but also led to large amounts of sediment and waste generated after wastewater treatment, placing strain on the environment. Since the beginning of the 21st century, this centralized treatment approach has been replaced by new decentralized wastewater treatment methods. The main new approaches to decentralized wastewater treatment in rural Germany are: 1. Decentralized municipal infrastructure systems. Advanced membrane bioreactors are installed in remote rural areas that do not have access to drainage systems; there, rainwater and wastewater are collected separately, and the wastewater is then purified using these advanced membrane bioreactors. It can not only reduce the costs of wastewater treatment but also yield nitrogen during the process of purifying wastewater, thereby turning wastewater into a valuable resource and enhancing the fertility of rural land. 2 Wetland wastewater treatment system. This process mainly involves channeling rural domestic wastewater through water pipes into sedimentation tanks; after passing through four layers of filtration in these tanks, the water is further purified using wetlands before being discharged in compliance with standards or used for irrigation in farmlands. The operation of this system does not require chemical agents; all materials are derived from nature, causing no secondary pollution to the surrounding environment. 3 Diversified wastewater classification treatment system. Wastewater is divided into rainwater, graywater, and blackwater. Grey water refers to domestic wastewater from kitchens, showers, and laundry, while black water refers to toilet wastewater discharged from vacuum toilets. Rainwater from rooftops and hard surfaces in residential areas is collected through rainwater pipes, and it flows into nearby surface water bodies or is directed to retention tanks installed within the residential area. This infiltration pond is part of the community’s landscaping facilities, and it appears to be part of the landscape design. Through this approach, rainwater can infiltrate the ground or directly enter the natural water cycle. Household wastewater from tasks such as washing vegetables, dishes, taking showers, and doing laundry flows as graywater through gravity-fed pipes to the plant-based water purification facilities in the residential area for treatment.