In 1860s, Dutch engineer Liernur invented a pneumatic sewer technology, which was applied in Amsterdam, Berlin, Paris and some other cities. However, for many reasons, not least due to the very limited technical at that time, this technology was completely replaced by natural gravity sewer plus lift pumping system in 1910s.

Until the 1970s and 1980s, thanks to technology development in all relevant industries, the pneumatic system was revived and became again available for the market, known as vacuum or underpressure sewer. But, as the European and American countries have meanwhile already completed the urbanization as a whole, this "new" drainage system could no more find wide application in the following decades and therefore also not greatly further developed. Whether it is architectural design or the design of sewage drainage system in urban and rural planning, The high water consumption, flushing the human waste to sewer and the end of the pipe treatment became a fixed pattern, limiting people's imagination in planning and design, and restricting the transformation of sewage system to a water-saving, smart, and resource-recovering system.

Unlike the gravity drainage system, the underpressure drainage system is not easily limited by building structure, environment, terrain and other conditions, and can be flexibly applied to various types of buildings, urban, rural and industrial park. As the liquid-air-mix has a higher speed than that in the gravity sewer, the underpressure system has a self-cleaning effect, can effectively avoid precipitation, makes it possible to convey medium with small flow rate but high-concentration, such as blackwater over a long distance. It provides effective means for the separated wastewater streams and intelligent treatment in civil and industrial areas. Since the diameter of the underpressure pipes is much smaller than that of the gravity flow, and the gradient does not need to be formed by gradually increasing the depth, the pipeline laying and construction become simpler.

At present, new problems and new ideas in the urbanization or infrastructure upgrading of emerging developing countries provide a broad space for the development of new drainage technologies.

The accumulated experience of China's rapid urbanization over the past three decades, the increasing awareness and demand for "ecological civilization" and "rural revitalization plan" have given birth to the overall improvement of the existing underpressure drainage technology and the highest level of the implementation.

EnviroSystems underpressure drainage technology mainly for:

• Green Building
• Ecological town
• Toilet revolution
• Sponge city
• Underground space
• Upgrade rural infrastructure
• Smart networking of pipelines
• Sewage management in coastal area

Principle

The underpressure drainage pipe network is similar with the tap waterin terms of system structure,except that the flow direction is in theopposite direction. It is a closed collection system, can conveyhigh-concentrated wastewater, and make "water flowingupward"possible.

SystemComposition

Interface/collection unit: collector, air flush toilet, etc.. Their main function is to collect and convey the wastewater into to the underpressure pipe.

Pipe network unit: link the interfaces in the form of a network and led to the collection station.

Collection station: generate and maintain the necessary under-pressure for servicing the whole system with a temporary storage capacity for the sewage.

Monitoring system: realize the automatic operation of the system, and remote monitoring, diagnosis and control when necessary.