JPH0649198B2 - Organic wastewater treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an improvement in a treatment apparatus for organic wastewater such as human waste, sewage, waste landfill exudate wastewater, and various industrial wastewater.
In particular, it is a very effective treatment device when mechanical means is used for solid-liquid separation of activated sludge after biological treatment.

[Conventional technology]

Taking human waste as the most representative organic wastewater as an example, the most advanced type of conventional human waste treatment equipment is recognized as the most advanced one after the biological nitrification and denitrification treatment equipment. Then, a solid-liquid separation device such as an ultrafiltration (UF) membrane is installed.

As this device, human waste is biologically nitrified and denitrified, the obtained activated sludge slurry is subjected to membrane separation of a UF membrane, and inorganic coagulants such as FeCl ₃ and alum are added to the membrane permeated water and left. CO
D, chromaticity and phosphorus are aggregated, and this aggregated floc is further U
Some of them have membrane separation by F membrane, and solid-liquid separation is reliable and perfect without being influenced by sedimentation of activated sludge, and operation management is easy.
Has attracted attention in the industry.

[Problems to be Solved by the Invention]

However, when evaluated from the standpoint of a total system for treating human waste by using such a conventional treatment apparatus, there were the following serious drawbacks.

That is, in the human waste treatment facility, a large amount of sewage such as the washing effluent of the human waste transport vehicle and the floor washing effluent is inevitably generated (when the human waste treatment amount is Qkl / day, the sewage drainage is usually 0.5
However, in the above-mentioned conventional device, the waste water is discharged into the biological nitrification / denitrification treatment device for urine and treated together with the urine. The amount of water flowing into the mechanical solid-liquid separation device for sludge increases. Since the equipment cost and running cost of the mechanical solid-liquid separator increase in proportion to the amount of inflow water, the conventional apparatus has a heavy burden on the user of the equipment cost and running cost, which is a problem.

In other words, the conventional device has no problem in the function itself of purifying both human waste and gray water, but another important function, that of purifying human waste as economically as possible, is extremely unsatisfactory. It was enough.

It is an object of the present invention to provide an energy-saving novel treatment device which rationally treats both human waste and gray water and saves both equipment cost and running cost as compared with the conventional device.

[Means for Solving the Problems]

The present invention provides a biological nitrification denitrification treatment device for organic wastewater, a mechanical solid-liquid separation device for separating activated sludge in biological treatment water flowing out from the biological nitrification denitrification treatment device, and activated sludge. It consists of a chemical injection device that injects an inorganic coagulant into the separated biologically treated water, and a membrane separation device that separates the biologically treated water that has been subjected to chemical injection by the chemical injection device into a membrane. A miscellaneous wastewater treatment device comprising a biological treatment part for treating wastewater and a chemical injection part for injecting an inorganic coagulant is installed in parallel, and the treated water of the miscellaneous wastewater obtained by the miscellaneous wastewater treatment device is treated with the membrane separation device. The apparatus for treating organic sewage is characterized in that a route leading to the outflow route of the membrane-permeated water is provided.

Further, the present invention is characterized in that a branch passage continuing to the inflow side of the membrane separation device is branched into a treated water path of the gray water, and the treated water of the gray water is further guided to a miscellaneous water use point. It is a treatment device for organic sewage.

[Work]

In the present invention, the organic sewage is treated with a biological nitrification and denitrification treatment device, the resulting mixed slurry of biologically treated water and activated sludge, activated sludge by mechanical solid-liquid separation such as centrifugation field and membrane separation. Separated to obtain biologically treated water, an inorganic coagulant is injected into the biologically treated water from a chemical injection device to form an agglomerated floc, which is fed to a membrane separation device to completely separate agglomerated flocs, etc. To obtain transparent membrane permeate.

On the other hand, various miscellaneous wastewater discharged in this treatment facility
The supernatant water obtained by being introduced into a wastewater treatment equipment separate from the above and biologically treated, injected with an inorganic coagulant, and subjected to solid-liquid separation by sedimentation separation, etc. is the final stage of the organic wastewater treatment. Has almost the same water quality as the permeated water that flows out from the membrane separator (slightly high SS only), and is combined with the permeated water for subsequent post-treatment such as activated carbon, ozone, chlorine sterilization, or Discharge as it is.

Further, most of the supernatant water (treated water) obtained by subjecting the gray water to biological treatment and undergoing solid-liquid separation by injecting an inorganic coagulant can be reused as water for miscellaneous use in the treatment facility. After use, it will be subjected to the biological treatment as waste water again. However, since salts accumulate in the water during continuous circulation in this way, a portion of the treated water of the gray water is supplied to the inflow side of the membrane separation device.

As described above, since the wastewater having a large amount of wastewater is not allowed to flow into the mechanical solid-liquid separation device for activated sludge in the treatment of organic sewage, the equipment cost and running cost of the solid-liquid separation device are significantly reduced as compared with the conventional device. .

〔Example〕

An embodiment of the present invention will be described with reference to FIG.
Reference numeral 2 is a biological nitrification / denitrification treatment apparatus equipped with an organic wastewater introduction pipe 1, and any type such as a known batch type or nitrification liquid circulation type is applied. 3 is a mechanical solid-liquid separation device for mechanically solid-liquid separating the activated sludge slurry flowing out of the biological nitrification denitrification treatment device 2, which is a membrane separator or a centrifuge.

The solid-liquid separated water (biologically treated water) from which the activated sludge has been separated by the mechanical solid-liquid separation device 3 uses a UF membrane, a precision filtration (MF) membrane, etc. via the biologically treated water outflow pipe 4 and the storage tank 5. And a chemical injection device 7 for injecting an inorganic coagulant and an alkaline agent injection device 8 for adjusting the pH.

In addition, a sludge dewatered separated water separated by a sludge dewatering pipe 9 and a sludge dewatering machine 15 which will be described later (also this is a wastewater Sludge dewatering / separation water outflow pipe 10 for discharging the sludge dewatering / separation water is provided, and a miscellaneous wastewater treatment device 11 for performing biological treatment such as batch activated sludge treatment by the intermittent aeration method is provided. An injection part 12 is provided.

Reference numeral 13 is a pipe line for drawing out the treated water of the gray water obtained in the gray water treatment device 11, and the membrane separation device 6 is provided in the pipe line 13 '.
While being merged with the membrane-permeated water outflow pipe 14, the pipe 13 ″ is recycled to the place where miscellaneous water is used.

The activated sludge discharge pipe 16 of the mechanical solid-liquid separation device 3 is divided into an activated sludge return pipe 16 'for returning the activated sludge to the biological nitrification and denitrification treatment device 2 and an excess sludge discharge pipe 16 ". The sludge discharge pipe 16 ″ and the coagulated sludge discharge pipe 17 of the membrane separation device 6 pass through the dehydration auxiliary agent addition section 18 and the sludge dehydrator 1
Open to 5. This sludge dewatering machine 15 uses a belt press,
Centrifugal dehydrator, screw press, filter press, etc. are used.

In the figure, 19 is a dehydrated cake discharged from the sludge dehydrator, 2
Reference numeral 0 indicates an air diffuser of the gray water treatment device 11, and reference numeral 21 indicates an excess sludge discharge pipe.

Thus, for example, the decontaminated urine is guided from the organic wastewater introduction pipe 1 to the biological nitrification and denitrification treatment device 2, and BOD, COD, nitrogen components (TN), etc. are biologically nitrification and denitrification treatment. After being removed by the treatment, the mechanical solid-liquid separation device 3 separates the biologically treated water into activated sludge, and most of the activated sludge discharged from the activated sludge discharge pipe 16 passes through the activated sludge return pipe 16 ′ to biology. It is recycled to the automatic nitrification and denitrification treatment device 2,
The surplus is supplied to the sludge dehydrator 15 from the surplus sludge discharge pipe 16 ″.

The biologically treated water separated by the mechanical solid-liquid separation device 3 is once stored in the storage tank 5 from the biologically treated water outflow pipe 4, and then an inorganic coagulant such as FeCl ₃ or polyiron sulfate is injected from the chemical injection device 7. In addition, an alkaline agent for pH adjustment such as NaOH, Ca (OH) ₂ is injected from the alkaline agent injecting device 8 to remove COD, chromaticity, PO ₄ ^-3 , colloidal SS, etc. under acidic conditions of pH _{4 to} 5.5. The aggregated flocs are formed and supplied to the membrane separation device 6 to completely separate the aggregated flocs into membranes. A tubular type or a flat membrane type is used as the membrane separating device 6 because SS blockage does not occur in the pipeline. Further, the flocculated flocs separated by the membrane separation device 6 are discharged from the coagulated sludge discharge pipe 17 and are dehydrated by the sludge dehydrator 15 together with the excess sludge discharged from the excess sludge discharge pipe 16 ″.

On the other hand, various sewage discharged from the treatment facility is led from the sewage introduction pipe 9 to the sewage treatment device 11, and is intermittently connected with the sludge dewatered separated water from the sludge dewatered separated water outflow pipe 10 of the sludge dehydrator 15. After being aerated from the air diffuser 20, an anaerobic / aerobic atmosphere condition is formed in the device, nitrogen and BOD components in the wastewater are removed, and then aeration and agitation are completely stopped and left to stand for activation. The sludge is allowed to settle, but before shifting to the stationary settling mode, the inorganic coagulant injection section 12
Inorganic flocculants such as FeCl ₃ , polyiron sulfate, PAC, Alum, etc. are injected and stirred, and PO ₄ ^-3 and non-biodegradable COD components remaining in the wastewater are flocculated to form activated sludge flocs. Take it into the county.

In this way, after the stationary settling mode set for the stationary time of about 1 to 1.5 hours is completed, the treated water as the supernatant water is withdrawn from the pipe line 13. This treated water is SS10mg /
Below, BOD, COD, chromaticity, phosphorus, and nitrogen were sufficiently removed, and the water quality was the same as the membrane permeated water obtained in the membrane separation device 6 (SS was slightly higher), and the pipeline 1
After passing through 3 ', it is merged with the membrane permeated water in the membrane permeated water outflow pipe 14 and subjected to a subsequent step, for example, post-treatment such as activated carbon, ozone, chlorine sterilization, or discharged as it is.

The treatment of gray water may be a continuous treatment type other than the batch activated sludge treatment method described above. In the case of the continuous treatment type, a solid-liquid separation section for activated sludge slurry is provided in the latter stage of the gray water treatment apparatus 11 and solid-liquid separation is performed by injecting an inorganic coagulant into the solid-liquid separation section. A coagulation separation part is installed after the liquid separation part, and the biologically treated water from which the activated sludge has been separated in the solid-liquid separation part is guided to the coagulation separation part and an inorganic coagulant is injected to perform coagulation separation. The water becomes the treated water for gray water.

Further, most of the treated water extracted from the gray water treatment apparatus 11 via the pipe 13 can be recycled again as the miscellaneous water for various washing via the pipe 13 ″.
In that case, the treated water recycled as miscellaneous water is again guided as miscellaneous wastewater from the miscellaneous wastewater introduction pipe 9 to the miscellaneous wastewater treatment device 11, and undergoes the above-mentioned treatment. Since salt is accumulated in the water while it is in the middle of water, which will impair the biological treatment and the pipeline, the branch pipe connected to the storage tank 5 on the inflow side of the membrane separation device 6 in the pipeline 13 'as shown in FIG. 22 is branched and a part of the biologically treated water is continuously or intermittently blown from the branch pipe 22 to the storage tank 5 to perform membrane separation to prevent the accumulation of salts.

The excess sludge from the gray water treatment device 11 is supplied to the sludge dehydrator 15 via the excess sludge discharge pipe 21, and is dehydrated together with other sludge.

〔The invention's effect〕

As described above, according to the present invention, the following extremely beneficial effects can be obtained.

Since the wastewater with a large amount of water is not allowed to flow into the organic wastewater treatment process, the amount of inflow water to the mechanical solid-liquid separation device following the biological nitrification / denitrification treatment device during the treatment process is significantly larger than that of the conventional device. In addition to the above, the amount of water flowing into the membrane separation device is significantly reduced as compared with the conventional device.

As a result, the equipment cost and running cost of the mechanical solid-liquid separator and the membrane separator will be reduced to at least 1 / 1.5 of the conventional equipment.

With the conventional device, even if an attempt is made to reuse highly treated water such as human waste as miscellaneous water, since the chloride ion concentration is as high as 1500 mg / degree, it is highly corrosive and practically impossible to reuse. However, in the present invention, since the gray water is treated separately, it is possible to obtain treated water having a chlorine ion concentration of about 200 mg /, and it can be reused as water for miscellaneous use.

[Brief description of drawings]

FIG. 1 and FIG. 2 are configuration explanatory views showing an embodiment of the present invention. 1 ... Organic wastewater introduction pipe, 2 ... Biological nitrification and denitrification treatment device, 3 ... Mechanical solid-liquid separation device, 4 ... Biotreatment water outflow pipe, 5 ... Storage tank, 6 ... Membrane separation Device, 7 ... Medication injection device, 8 ... Alkaline agent injection device, 9 ... Miscellaneous drainage introduction pipe,
10 ... Sludge dewatering separated water outflow pipe, 11 ... Miscellaneous wastewater treatment device, 12 ... Inorganic coagulant injection part, 13, 13 ', 13 "
...... Pipeline, 14 ...... membrane permeate water outflow pipe, 15 ...... sludge dewatering machine, 16 ...... activated sludge discharge pipe, 16 '...... activated sludge return pipe, 16 "...... excess sludge discharge pipe, 17 ...... Coagulated sludge discharge pipe, 18 ... Dehydration auxiliary agent addition section, 19 ... Dewatered cake, 2
0 ... Air diffuser, 21 ... Excess sludge discharge pipe, 22 ... Branch pipe.

Claims (2)

[Claims] 1. A biological nitrification denitrification treatment device for organic wastewater, a mechanical solid-liquid separation device for separating activated sludge in biological treatment water flowing out from the biological nitrification denitrification treatment device, and activated sludge. It consists of a chemical injection device that injects an inorganic coagulant into the separated biologically treated water, and a membrane separation device that separates the biologically treated water that has been subjected to chemical injection by the chemical injection device into a membrane, and is discharged at the treatment facility. A sewage treatment apparatus comprising a biological treatment section for treating sewage and a chemical injection section for injecting an inorganic coagulant is installed in parallel, and the effluent treatment water obtained by the sewage treatment apparatus is subjected to the membrane separation. A treatment device for organic wastewater, characterized in that a route is provided to lead to the outflow route of the membrane-permeated water of the device. 2. A biological nitrification and denitrification treatment device for organic wastewater, a mechanical solid-liquid separation device for separating activated sludge in biological treatment water flowing out from the biological nitrification and denitrification treatment device, and activated sludge. It consists of a chemical injection device that injects an inorganic coagulant into the separated biologically treated water, and a membrane separation device that separates the biologically treated water that has been subjected to chemical injection by the chemical injection device into a membrane, and is discharged at the treatment facility. A sewage treatment apparatus comprising a biological treatment section for treating sewage and a chemical injection section for injecting an inorganic coagulant is installed in parallel, and the effluent treatment water obtained by the sewage treatment apparatus is subjected to the membrane separation. A route leading to the outflow route of the membrane permeated water of the device is provided, and a branch passage connected to the inflow side of the membrane separation device is branched to the route, and the treated water of the miscellaneous wastewater is further guided to a place where the miscellaneous water is used. An apparatus for treating organic wastewater, characterized by: