According to the 2013 Statistical Communiqué on National Economic and Social Development issued by the National Bureau of Statistics, the daily treatment capacity of urban sewage treatment plants at the end of 2013 reached 118.58 million m3, and the urban sewage treatment rate reached 84.9%.With the continuous increase of sewage treatment volume, a large amount of sludge has been produced, and the treatment and disposal of sludge has received extensive attention.
The sludge produced by the sewage treatment plant is complex before it is deeply treated. It contains a lot of harmful substances such as heavy metals, viruses and parasite eggs. The water content is generally above 95%. It is easy to be spoiled and easily cause secondary pollution. Therefore, sludge must be applied. Harmless and stabilized.
The methods for final disposal of sludge at home and abroad mainly include landfill, incineration, agricultural use, etc.The final disposal methods of these sludges are faced with the problem of how to reduce the moisture content of the sludge. Ultrasonic technology has been used in the treatment of excess sludge due to its cleanliness, simple operation, cavitation and mechanical effects.generally used as a sludge pretreatment means to improve the dewatering of sludge.
Flocculant cationic guar gum (CGG) is an agent obtained by amination and cation modification of guar gum.Currently used mainly as a thickener and conditioner, it has been reported to be used as a flocculant in the field of wastewater treatment.
The natural modified flocculant CGG has the advantages of wide source, no secondary pollution and easy degradation, and is an environmentally friendly flocculant. Its flocculation mechanism mainly has two aspects.On the one hand, the cohesion caused by electrical neutralization; on the other hand, by the cross-linking adsorption between suspended solids.