JPS6089B2 - Sludge dewatering treatment method and its equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for dewatering sludge collected from a sewage treatment plant.

Conventionally, sludge collected from sewage treatment plants has a high water content and cannot be dumped, landfilled, or fermented as it is, so it is dehydrated.

However, as shown in Fig. 4, this dewatering method involves adding an appropriate amount of flocculant from the flocculant tank 8 while transporting the collected sludge with a high water content from the sludge storage tank 1 through the sludge transport pipe, and then flocculating it. It is fed into the mixing concentration tank 6, then supplied to the belt press type dehydrator 12, and after the desired dehydration is performed, it is sent to the next process as a dehydrated cake, and the wastewater discharged from the dehydrator 12 is sent to the settling tank. 24, and the sludge particles are precipitated therein, and the top water is supplied to the washing nozzles 18 and 19 of the dehydrator 12 and used as washing water.

However, in this method, the sludge is flocculated with a coagulant and then directly supplied to the dehydrator together with the separated water for dewatering, resulting in poor dewatering efficiency and poor reuse efficiency of the desorbed water as washing water. In view of this, the present invention has been devised to improve dewatering efficiency while efficiently reusing desorbed water. Next, the present invention will be described in detail with reference to the illustrated embodiments.

In the figure, reference numeral 1 denotes a sludge storage tank for storing sludge collected from a sewage treatment plant, etc., into which sludge with a high water content is transferred using an appropriate transfer means.

Reference numeral 2 denotes a strainer which is supplied from the sludge storage tank 1 through the sludge transport pipe 3 and which removes bulky waste in advance. While supplying sludge to the tank 6, the static mixer 5 is supplied with the dissolved flocculant from the flocculant dissolving tank 7, and the flocculant is supplied from the flocculating liquid tank 8 stored therein through the flocculating liquid supply pipe 10. In this static mixer 5, the sludge and this flocculated liquid are mixed.

In addition, a flocculating liquid supply pipe 9 is provided so that the flocculating liquid can also be injected into the sludge transport pipe through a static mixer or other mixer. Flowmeter 12a, 12b, 1
2c is provided, and the flocculating liquid is injected and mixed in an adjustable required ratio with respect to the amount of sludge.

The flocculation-mixing concentration tank 6 is installed in a horizontally rotatably supported sieve drum 22, and the sludge and free water flocculated in the sieve drum and the flocculation tank 6 are separated by a furnace, and the flocculated sludge is sent to the next process. The free water is supplied to a belt press type dehydrator 12 or filtered in a sieve drum, and then led to a tank 13 provided at the lower part of the coagulation-mixing thickening tank. At this time, the cleaning water is led to the tank 13 together with the cleaning water jetted out from the sheave drum cleaning nozzle 14 provided on the upper part of the sheave drum 22 for cleaning the sheave drum.
A chute 23 for receiving desorbed water is provided at the lower part of the belt press type dehydrator 12, and the desorbed water collected in the chute is supplied into the sheave drum 22 through a washing water pipe 17 by a pump 16. A portion of the cleaning water in the tank 13 is supplied to the cloth cleaning nozzles 18 and 19 of the dehydrator through a pump P, and this tank 13 receives a makeup water pipe 20 and a drain pipe 21. The sludge collected from sewage treatment plants, etc. is mixed with flocculation liquid and supplied to the flocculation mixing tank installed in the sieve drum.The sieve drum is also supplied with desorbed water from the dehydrator, and the sludge is is coagulated in the rotating coagulation-mixing concentration tank 6, solids in the waste water are filtered and removed in a sieve drum, and free water is drained from the sieve drum to separate the solids and water. To prevent clogging, cleaning water is sprayed from a cleaning nozzle above the outer periphery of the sheave drum.

The solid content of the sludge separated by this sieve drum is removed by the dehydrator 1.
The free water separated from the sieve drum is temporarily stored in a tank and sent to the sieve drum cleaning nozzle and dewatering machine using a pump. The water is supplied to the furnace cloth cleaning nozzle and used as cleaning water, and the dehydrated water dehydrated by the dehydrator is supplied to the sieve drum by a pump. In this way, the dehydrated water is reused and the sludge is removed. The dehydration process is performed continuously. Further, the waste water from the dewatering machine may be supplied to an input chute 15 provided in the sieve drum. According to the present invention, a large amount of washing water required for cleaning the furnace cloth of the dehydrator can be obtained without requiring outside the system, and at the same time, solids mixed in the waste water by cleaning the furnace cloth can be removed from the sieve drum, which is another equipment in the system. Since the furnace cloth cleaning wastewater (containing solids) can be treated by the system, it is possible to prevent the furnace cloth cleaning wastewater (including solids) from flowing outside the system without installing new equipment.Furthermore, the furnace cloth cleaning water can be reused, and as a result, there is no need to install any new equipment from the outside. This makes it possible to clean the furnace cloth of the dehydrator without having to receive a water supply and without adding new equipment.As there is no need to add new equipment, the equipment can be made more compact, and the equipment is simple.
It has the advantage that sludge can be continuously dehydrated to a desired moisture content.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of the present invention, FIG. 2 is an external view of a flocculation mixing tank, FIG. 3 is a cross-sectional view of FIG. 2, and FIG. 4 is an explanatory diagram of a known flow. 1... Sludge storage tank, 2... Strainer, 3... Sludge transport pipe, 4... Sludge pump, 5... Static mixer, 6... Coagulation mixing thickening tank, 7... Coagulation agent dissolution tank, 8... coagulating liquid tank, 9, 10... coagulating liquid supply pipe, 11... sludge transport pipe, 12... dehydrator, 12
a, 12b, 12c...flow meter, 13...tank, 14
...Washing nozzle for sheave drum, 15...Input chute, 16...Pump, 17...Washing water pipe, 18,
19... Source cloth cleaning nozzle, 20... Supply water pipe, 21
...Drain pipe, 22...Sheave drum, 23...Chute. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. Mixing flocculating liquid with sludge in a required ratio and supplying the mixture to a flocculation-mixing thickening tank provided in a sieve drum, removing separated water in the sieve drum, and then supplying the flocculated sludge to a dehydrator. , At the same time as performing the desired dewatering, the dewatered water from the dehydrator and the filter cloth washing wastewater from the dehydrator are supplied into the above sieve drum, solids are separated, the separated solids are combined with the flocculated sludge, and then discharged from the sieve drum. A method for dewatering sludge, characterized in that the filtered and separated water is pumped to a filter cloth cleaning nozzle and a sieve drum cleaning nozzle of a dehydrator to be used as cleaning water. 2. A sieve drum is arranged horizontally, and a coagulation mixing thickening tank is provided in the sieve drum to which the sludge is mixed with a flocculating liquid, and a belt press is installed adjacent to the sieve drum to dewater the flocculated sludge discharged by the sieve drum. A type dehydrator is provided, and a cleaning nozzle for the sieve drum and a filter cloth cleaning nozzle are provided in the dehydrator so as to be supplied with dehydrated water from the dehydrator, and dehydrated water from the dehydrator and wastewater for cleaning the filter cloth are provided. A sludge dewatering device that has a pipe line so that it can be supplied into the sieve drum.