JP2001239300A - Sludge treating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To separate sludge from water by perfectly floating the sludge for a short time at the most important solid-liquid separation step in the continuous steps and to reduce the moisture content, which is 75% in the present state, of the cake-shaped sludge after dehydration. SOLUTION: At first, charcoal powder and chitosan in the natural field is added to liquid sludge by about half of the liquid sludge or smaller based on measurement weight without using chemicals for making the sludge apt to flocculate and float. Next, the power of bubbles, which are generated when the pressurized oxygen solution prepared beforehand is purged into the liquid of atmospheric pressure, is used as assistance for floating the sludge for a short time in a floating tank where the concentrated sludge is gathered by pumping it up. The floated sludge is dehydrated to obtain cake-shaped sludge that has 800% moisture content and about one-tenth volume of the concentrated sludge. The cake-shaped sludge contains the charcoal powder of 100% or more amount of the total solid content and can be dried at accelerated drying speed by making good use of air permeability being the characteristic of the charcoal powder and generating cracks in the sludge having viscosity. The obtained sludge is used as not only a nonpolluting soil reducing material but also a good agricultural material by composting it into fertilizer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to solid-liquid separation wastewater and sewage sludge treatment in which fine bubbles are attached to sludge into which charcoal powder and a chitosan solution have been injected.

[0002]

2. Description of the Related Art Due to an increase in the treatment amount and diversification of sludge properties, it has become difficult to treat the technology. Therefore, a polymer flocculant, which is a chemical, or an inorganic ferric chloride, slaked lime, etc. At present, they are used for drying and then dehydration and drying and incineration. However, in this method, only about 10% of the whole is used for recycling. The reason is that the use of chemical agents causes excessive salt and is not suitable for soil reduction. Therefore, there is a large amount of waste in the incineration direction, and there are also problems with the technology of exhaust gas treatment due to recent environmental problems. In addition, the sludge has a high viscosity and incineration with an average water content of 75% requires a huge cost for incineration equipment. At present, running costs are high, and outsourcing is also paying excessive processing costs.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to make the sludge float in a short time after entering the floating tank, and to eliminate the bad smell of the sludge. Since the problem of time is proportional to the amount of raw water,
This is because there is a limit to the space of the treatment plant in the process. Since the process is a continuous process, the time matches the entire flow. Therefore, a short process is required until the dehydration process. The above should be considered as a technical issue, and the major goal of recycling and non-polluting soil reduction should be achieved by the treatment that comes from the combination of additive materials for the next treatment. In addition, if the cake-like product after the dehydration process has a sufficient receiving system for soil reduction, it is necessary to turn to the current incineration method. is there. The challenge is to significantly reduce the cost of sewage treatment as a whole. In addition, there is a problem as an agricultural material that can be used safely and continuously as a recycled material for the future.

[0004]

The technical solution is to use charcoal powder and a chitosan solution. Charcoal powder is characterized by micropores with a large specific surface area, which makes it smaller in volume, so it has an element of buoyancy in water,
In addition, chitosan solution is a natural product similar to charcoal, so it is known in many wastewater treatments that it has no pollution and is excellent in cohesion. When the buoyancy is given to the sludge by the lightness of the specific gravity of the former and the cohesive force of the latter, the sludge is further raised in the flotation tank to obtain the energization of the fine bubbles and completely float and separate in a short time. It is already known that the pores of charcoal powder adsorb and remove odors. In addition, since charcoal powder is excellent in air permeability, after the sludge is dewatered, a viscous sludge is cracked and the drying speed is increased. Therefore, using this mechanism to tackle the machinery and equipment will greatly increase the drying efficiency by greatly reducing the water content. In particular, after dehydration, in the case of turning to soil reduction instead of incineration, there is no obstacle in terms of components, and it is the direction in the direction of return. In addition, when composting is used, by simply multiplying the number of days by about one week, actinobacteria function to make the compost strong against the formation of the aggregate structure.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The inventor has previously attempted to float and separate sewage sludge using charcoal powder. However, since it takes three to five days to completely ascend as a result, the space is not already available unless the processing is performed away from the city, and it does not become an urban one. Under such circumstances, when charcoal powder was mixed with the feed at the eel eating place, it was heard that low bed sludge floated as if the seat buton floated from the low floor in a short day, and one of them was already pressurized flotation method I knew that there was a problem, so I thought about the effect of the combination and immediately implemented it.

[0006]

Example 1 Charcoal flour is not limited to wood species, but softwood is advantageous because it has a low bulk density. In addition, since the particle size of the charcoal powder is also related to the bulk density, it is determined to be less than 2 mm from the experimental results. This is because if the particles are made finer, the cost increases due to the charcoal productivity, and at the same time, it causes scattering and deteriorates the workability. Also, if it is larger than 2 mm, the bulk specific gravity is affected. Next, the production temperature of charcoal is important. This is because the properties of charcoal vary greatly depending on the production temperature, that is, the treatment temperature. As described above, the use of low-temperature coal is most advantageous in the present invention because the bulk weight in the physical properties has the most influence. Therefore, softwood low-temperature coal such as cedar, cypress, and larch is the most suitable material for the present invention. The moisture content of the charcoal powder itself is 15% to 25%
Is an appropriate rate, and when it is 15% or less, splatters appear as in the case of fine powder, resulting in poor workability. The stirrer is for improving the familiarity with the sludge on the whole and for coagulation.

[0007]

Embodiment 2 The role of the charcoal powder of the present invention is to raise a solid product to a specific gravity of 1.0 or less in a liquid having a specific gravity of 1 of the concentrated sewage sludge, and therefore, the charcoal powder is relatively small in the charcoal powder. It is desirable to use a low-temperature coal having a high hydrophobicity, that is, a high volatile content, and to have a low volumetric gravity. The ratio of the charcoal powder injected into the final concentrate is 0.2% based on an average water content of 98% of the final concentrate. Many are good because they affect the processing cost.

[0008]

Embodiment 3 The chitosan solution makes a 1% chitosan solution. 1% solution means 1g of chitosan in 50cc of water
And mix with standing water for about 15 minutes. Next, 10 cc of 1N organic acid (complex acid) is added and stirred. And 100c
Water was added until it became c. The solution prepared in the above ratio is mixed into the sludge with the same 10 ppm as the sludge as the charcoal powder. This chitosan solution serves to coagulate the sludge. The charcoal powder plays an active role in the subsequent drying step and the like, but it takes a long time to float with the charcoal powder alone until flotation and separation, so that it is not based on a predetermined continuous process. Therefore, it was selected as the same natural coagulant. In this approach, the 1% chitosan solution is subsequently injected and stirred into an injection tank with a stirring device containing charcoal powder.
When the stirring is completed, the process proceeds to the next pressurized flotation tank, where the oxygen solution in the previously prepared pressurized tank is introduced in the atmosphere, so that fine bubbles immediately adhere to the sludge and simultaneously float on the entire surface, and solidify. It performs liquid separation.

[0009]

In the field of wastewater treatment and sewage treatment, it is now an alarm that the majority of treatment methods are proceeding in the incineration direction as an environmental problem. Under such circumstances, it is social contribution to use charcoal powder and chitosan, which are natural products, to achieve this purpose without using chemicals for the ultimate purpose of reducing the soil and reducing the soil. There are no other disadvantages. It is a meaningful thing that can be started immediately.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4D015 BA02 BA03 BA12 BA17 BA22 BB08 BB12 CA12 DA31 DB32 DC02 DC04 EA33 4D028 AA03 AC01 AC06 AC09 BE08 4D037 AA11 AB02 BA02 BA04 BB08 BB09 4D059 AA03 BE41 BE55 BK02 DA03 DA61 BA12 BA17 BA22 BB08 BB12 CA12 DA31 DB32 DC02 DC04 EA33

Claims (2)

[Claims] 1. Charcoal powder from a raw sludge raw water through an initial settling process to an activated sludge process, or from a concentrated sludge stage through a digestion tank to a halfway point between a pressurized flotation tank and a next step. In addition, a chitosan solution injection tank is installed. Then, the chitosan solution is injected and stirred with a metering injector while the predetermined charcoal powder remains powdery. Subsequently, the charcoal is advanced to a pressurized flotation tank to obtain the energization of fine bubbles generated in the atmosphere by an oxygen solution introduced from a pre-formed pressurized tank, and to completely separate and float the sludge from water in a short time, charcoal. Processing method combined with pressure flotation method using powder and chitosan solution. 2. The method of generating bubbles is not limited to the pressure-floating method, and is a processing method using another fine bubble generator.