In allusion to the problem of short supply of nitrogen gas,the reform of oxygenerators for the utilization of foul nitrogen gas in production was proposed and implemented in order to increase nitrogen gas supply,reduce oxygen emission rate and meet the requirements of users.

Analysis on the characteristics of the nitrogen pollution in Weihe River;

Reason and prevention measures of nitrogen pollution in groundwater at Yinchuan Area;

Analysis on the influence factors of the nitrogen pollution in shallow groundwater;

Animal husbandry exerted very important effects on meat product supply,people\'s life improvement and farmer\'s income increase,but the nitrogen of livestock manure polluted the environment,so it was important to strengthen the research about nitrogen pollution and environmental cost of livestock manure.

It's a effective and valid method to cultivate and enrich denitrifying sludge,by adopting the stage by stage rising method.