Techase Dedicated to River Silt Treatment for Flood Control

In the summer of 2017, monitoring data from the Hunan hydrographic bureau showed that Hunan recorded 20.5 days of rain in June, the accumulated average rainfall in the province was 407.1 millimeters, which was equivalent to the waters of five Dongting Lakes in Hunan. It broke through the historical weather records from 1951. Changsha, the provincial capital, was the region with the most severe storms. From June 22 to July 2, the average cumulative rainfall in Changsha was 435 millimeters, exceeding 120 millimeters recorded during the 1998 flood.

As of July 19, this round of flooding had affected about 4,030,000 people in 1,207 villages and towns in 115 counties (cities, districts) of 14 city states in Hunan province. Over 310,000 people were transferred and 6,369 houses collapsed. It caused the direct economic losses of 6 billion yuan. The direct economic loss of water conservancy facilities was 1.37 billion yuan.

What caused the flood? The main reason was the continuous heavy rain, which was rare in a hundred years. The river and lake, as the main force for rapid diversion of rainwater, “reversed and betrayed” at the key moment. As a result, a large number of rivers and lakes poured into the city.

What prevents the diversion of rivers and lakes? That must be the mud under the river and the lake. A lot of sludge deposition slowed down the discharge of rainwater. When the floods receded, the relevant government departments in many places in Hunan had already conducted dredging work for some rivers. How to dispose and clear the river silt? Because dredging of rivers and lakes will produce a lot of high water content, high organic matter, and even poisonous and harmful dredging mud. Therefore, the treatment and disposal of sludge from dredging had become a hot topic of concern.

Quickly and effectively treating and disposing the large-scale mud in the form of “reduction, harmless, and stabilization” had become the key to the smooth implementation of urban dredging and dredging projects.

Techase combined its own technological advantages and provided a reasonable and efficient solution to the problem of silt disposal in rivers and lakes under these circumstances. According to the different conditions on the site and different customer requirements, flexible process were adopted to realize the dredging, treatment and disposal of river silt.

Let's see how it was handled in the end.

After the mud transported to the shore, which were excavated by the dredger, it were processed by the garbage sorting equipment and the sand water separation equipment. At the same time, in the event of heavy metals and highly polluted mud, special conditioning was required. Heavy metals and high pollutants were separated and stabilized in a timely manner. Finally it was treated by mechanical dewatering or geotube.

Method 1, mechanical dehydration

The treated mud was pumped to a special quick press for dredging in rivers and lakes or a special screw machine for dredging in rivers and lakes for rapid dehydration. The tail water was returned to the water body or the tube after being settled and filtered. The dehydrated sludge can be disposed of according to the actual conditions of the project. It can be used as garden soil, engineering soil, building materials, etc.

Method 2, geotube

The treated sediment was injected into the geotube. Then through flocculation, sedimentation and drain filtration, the volume can be greatly reduced. Geotube reduced the requirements of land using by multi-layered stack. The process is completely closed and pollution-free. It is a cheap and environmentally friendly method of treating sediments in rivers and lakes. Silt dehydration consolidation process eliminates the secondary pollution problem that occurs during dredging and ensures the smooth implementation of the dredging project.