According to the technological characteristics of boat-type precipitator in an integrated oxidation ditch,the article discussed some phenomena that active sludge sedimentation rate descend and abnormal draining sludge in sludge funnel and "sludge flow" in drainage weir of precipitator,and analyzed the principium in hydraulics.

The techniques of blasting cutting a wreck to clear up the waterway are introduced.

The experience of wreck clearing away and salvage in inland waterway is introduced and improvement measures and tentative ideas are approached.

Where the vessel sinks in the harbour or the waterway with cargo on board, the wreck should be removed compulsorily by the harbor authority according to the relevant law of P.

Passing lifting wire through the sunken ship is key working procedure for sunken ship salvage.

The salvaging program for the “haifeng” sunken ship in water areas near the deep water channel of entrance of Yangtze River, blasting parameters and implementation method are introduced.

The nature of compulsory wreck removal from view of private law;

Research on the Legal Responsibility of Mandatory Wreck Removal;

A Research on the Legal Issues Relating to Wreck Removal for Public Welfare;