It points out that traditional gravity pollution discharge system consumes large amount of freshwater resources and brings about the unable reclaim of the nutrition components of N,P,K in civic feces wastewater because of the dilution of civic feces.

A drainage system of high-pressure compressor is introduced.

In view of problems in blowdown system of boiler, some idea about design and operation are put forward.

On the basis of an analytical study of the blow down system of four 20 t/h industrial boilers the system as a whole underwent an upgrading from the perspective of energy saving.

Comparing siphon drainage system with gravity drainage system, the paper considers the siphon drainage system to possess many advantages such as small pipe dia, little installing space, non-sloped suspended pipe, short sewage connecting and underground pipe length etc.

Compared with gravity drainage system, it has the advantages of small pipe diameter and installing space, non-sloped suspended pipe, less sewage connecting and underground pipes and etc.

The vacuum drainage system is adopted in reconstruction of a subway shopping centre due to the following reasons:poor air ventilation in the underground shopping centre;trying not to affect current constructions;and difficulties to set gravity drainage systems.