Combined with an engineering example of backwash blow down of plate hate exchanger in a cold supply engineering of Guangzhou,the different backwash methods of air conditioning main server room plate heat exchanger and terminal plate heat exchanger were introduced.

Taking Huaze aluminum electric air-cooled unit as the example, this paper probes into the initial flushing process of 300 MW direct air-cooled units, and introduces in detail its flushing methods and flushing principles.

In order to ensure the stable and better working environment and reduce the treatment effect on the following treatment process,the working cycle,the flushing index,the flushing method and the control parameters of the biological contact oxidation process are discussed in this paper according to characteristics of the biological film.

Through the experiment, combined air-water backwash mode was taken in BAF backwash and water backwash were 5～7 L /(m2·s) and air backwash 13～17 L /(m2·s) with the backwash period 24 h and the backwash time 15 min.

Study on the filtration and backwashing for the quartz filter in micro-irrigation;

Parameters experiment of backwashing on sandy filter in micro-irrigation;

Study on backwashing of bio-filter bed of iron and manganese removal in steady running period;

Study on Backwash Properties of Biological Aerated Filter;

The results showed that the optimal press is 19～65 kPa and the optimal interval of backwash is 25 min.

It was found that PAC addition was effective in enhancing flux and that flux could be recovered by backwash,suggesting that PAC can prevent membrane from fouling.