JPH027624Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a sludge dewatering device that performs gravity dewatering of sludge and then pressure dewatering.

In the dewatering treatment of settled thickened sludge, it is common to add and mix a polymer flocculant to the sludge in advance, and then directly feed the mixed sludge to a filter press for dewatering.
Therefore, for example, if the initial sludge concentration is 3%, the polymer flocculant solution concentration is 0.1%, and the addition rate is 1.0% to water, the sludge volume is 100: the polymer solution volume is 30, and the sludge is Although it is aggregated, the concentration is about
In addition to being diluted to 2.3%, the volume supplied to the filter press increases by approximately 1.3 times, which poses the problem of worsening dewatering conditions such as sludge concentration and throughput.

Therefore, the applicant of the present application focused on the fact that the filtration rate, that is, the dewatering rate, increases as the sludge concentration increases, as shown in Figure 2. We have proposed a technique that solves the above problem by adding and mixing a sludge agent, dewatering the mixed sludge by gravity, and then supplying it to a filter press to dehydrate it under pressure. However, in this disclosed technology,
When the pump supplies sludge after gravity dewatering to the filter press, if the sludge particles have a large diameter of around 10 mm, only water is sucked into the pump from the sludge tank after gravity dewatering, and the solid content is supplied to the filter press. A difficult problem has arisen.

The purpose of this invention is to solve the above problems and provide a sludge dewatering device with high dewatering efficiency.

That is, by adding and mixing a polymer flocculant to sludge,
In a device that dewaters the mixed sludge by gravity and then supplies it to a filter press for pressure dehydration, the sludge tank after gravity dewatering is shaped like a funnel, and the dehydrated sludge is supplied to the filter press from the bottom via a sludge pump. This is how it was done.

Hereinafter, embodiments of this invention will be described based on the accompanying drawings.

As shown in FIG. 1, sludge is sent from a settling tank or the like to a rotary mixing tank 1, a polymer flocculant is added thereto, mixed, and then fed to an endless filter type gravity dehydrator 2. In the dehydrator 2, the mixed sludge is moved together with the filter cloth for gravity dewatering, and the sludge after gravity dewatering is sent to a hopper-shaped sludge tank 3 installed on the discharge side. Collect the filtrate in water tank 4.

A pipe leading to a sludge pump 5 is connected to the bottom of the sludge tank 3, and the pipe is also connected to a filter press 6, and the pump 5 supplies sludge after gravity dewatering from the sludge tank 3 to the filter press 6 for processing. Pressure dehydrate. As the pump 5, a piston pump, screw pump, or the like is used.

Since the sludge tank 3 is funnel-shaped in supplying sludge to the filter press 6,
Solids with heavy specific gravity are collected at the bottom of the sludge, and pressure is further applied by the water level, so the suction of the pump 5 supplies the sludge containing not only water but also sufficient solids to the filter press 6, resulting in high filtration speed. Dehydration takes place. Furthermore, if a lid is provided on the sludge tank 3 and the inside of the tank 3 is pressurized with a compressor or the like while the lid is sealed, sludge can be more smoothly supplied to the filter press 6, and the supply flow path can be If it is a flowing type, that is,
If the bottom discharge port of the sludge tank 3, the pump, and the sludge inlet of the filter press are placed in the lower order in order so that the sludge flows down naturally, the supply operation will be made even smoother.

In addition, in the example, when the concentration of sludge fed into the mixer 1 is 2 to 5%, the sludge concentration in the sludge tank 3 is 6 to 10%, and the filtrate obtained by gravity dewatering is usually ss: 50 to 10%. Since the concentration is 100 ppm, this filtrate may be used as filter cloth washing water for the filter press 6 using the pump 7 as shown in the figure.

As described above, according to the sludge dewatering device of this invention, when coagulated sludge is subjected to gravity dewatering and then pressurized dewatering, a funnel-shaped sludge tank is provided on the discharge side of the gravity dehydrator, and the sludge tank is drained from the bottom of the sludge tank. Since the dewatered sludge is supplied to the filter press via the sludge pump, solids collect at the bottom of the sludge tank and are pushed out to the pump side by water level pressure, so the water content of the sludge is reduced as before. Sludge containing sufficient solid content is supplied to the filter press without being supplied with only sludge, resulting in efficient dewatering.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an embodiment of the sludge dewatering apparatus of this invention, and FIG. 2 is a diagram showing the relationship between sludge concentration and filtration rate. 1... mixer, 2... gravity dewatering machine, 3... sludge tank, 5... sludge pump, 6... filter press.

Claims (1)

[Scope of utility model registration request] A mixer that adds and mixes a polymer flocculant to sludge, an endless filter type gravity dewaterer that receives and moves the mixed sludge discharged from this mixer and performs gravity dewatering, and further pressurizes this dehydrated sludge. In a sludge dewatering device comprising a filter press for dewatering, a funnel-shaped sludge tank is provided on the discharge side of the gravity dehydrator, and dehydrated sludge is supplied to the filter press from the bottom of the sludge tank via a sludge pump. Sludge dewatering equipment.