JPS5990695A - Treatment of waste water - Google Patents

Abstract

PURPOSE:To eliminate ammonia nitrogen (NH4-N) and nitrate nitrogen (NOX- N) in a single reaction tank with high efficiency by setting up the oxidation- reduction potential of the liquid to 100mV in the single reaction tank under air supply, and removing NH4-N and NOX-N at the same time. CONSTITUTION:A sensor 9 for the oxidation-reduction potential (ORP) is provided in a liquid mixture of a reaction tank 10 in which waste water 1 in high concentration is treated directly without dilution, and the ORP value of the liquid mixture is measured and recorded continuously. The quantity of air 8 for aeration is controlled so as to confine the ORP value within the range of 0- 100mV. If the ORP value is confined within the range, the dissolved oxygen (DO) value which is important for keeping the function to remove NH4-N is controlled necessarily to the suitable range of 0<DO<1ppm. By operating the reaction tank at the above mentioned ORP value, the removal of NH4-N and NOX- N is carried out simultaneously with high efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention enables human waste, livestock manure, fisheries processing wastewater, etc. to be processed without dilution, and with very low dilution, and in a single tank.
The present invention relates to a method for highly efficiently removing 4-N and NoX-N.

When directly undiluted biological treatment of high-concentration waste liquid (e.g. human waste, livestock manure, fisheries processing wastewater, etc.) that exceeds the scope of application of the normal activated sludge method, living insects can be grown in a single reaction tank under air supply. NH4 is produced by the cooperative action of nitrifying bacteria (proliferates in aerobic conditions) and denitrifying bacteria (propagates in anaerobic conditions), both of which have completely different conditions.
-N (ammoniac nitrogen) removal and NOX-N (No2
-N and NO3-N) removal is performed simultaneously. However, a stable operation method that maximizes the activity of both substances, which have different physiological characteristics, and allows NH4-N removal and NOX-N removal to coexist with high efficiency has not been known so far.

The present invention provides a method that can achieve highly efficient NH4-N removal and NOX-N removal in a single tank, and directly treats high-concentration nitrogen-containing waste liquid, which is beyond the scope of application of the normal activated sludge method. In the method of biological treatment using no dilution or extremely low dilution, NH4-N can be removed simultaneously in a single reaction tank under air supply.
The present invention relates to a wastewater treatment method characterized by setting the redox potential of the reaction ellipsoid to a range of 0 to 100 mV (excluding 07) ZV in order to remove oX-N with high efficiency.

FIG. 1 is a diagram showing an example of an embodiment of the method of the present invention.

As shown in Fig. 1, in a reaction tank 10 that directly processes the high concentration waste liquid 1 without dilution, an ORP (redox potential sensor 9) is installed in the reaction tank mixture to continuously measure and record the mixed liquid ORB value. Then, adjust the amount of aeration air so that this ORB value falls within the range of 0 to 1 oomv (note that when ORP falls within this range, 1 is required to maintain the NH4-N removal function, and the o value is 0〈DO (1p
pm tic necessarily controlled.

In the figure, 2 is a return sludge line, 6 is an electric motor, 4 is a blower, 15 is an aeration device, 6 is a treated liquid extraction line, which leads to the sludge separation process (not shown), and 7 is an exhaust gas extraction line. Must have.

The method of the present invention will be specifically explained below using experimental examples.

Experimental equipment (as shown in Figure 1) Reaction tank 10: 20 silent reaction tower Tower diameter 1.9m, effective liquid depth 7m Aeration device 5: Rotary atomizer (500 cup-shaped rotating bodies Rotate at ~600 rpm, Supplying aeration air into the cup apply).

Diameter 0.45m Height 0.675771 Target waste liquid undiluted human waste: BOD 8800 ppmTota
l-N 3100 ppm NH4-N 2600 ppm Experimental conditions ORP: -50 to +1507'nV change in processing amount:
10n//day air amount: 30-250 Nrr? /hr Changes liquid temperature: 2
5 to 30°C Figures 2 and 3 show the results of the study of the NH4-N removal rate, NOx, and -N removal rate obtained in the above experiment.

In addition, in Figures 2 and 6, ORB is in the range of +40 to +100 mV, and DO is 0.4 to 1.0 ppm, p,
The treatment solution (DNO, -N concentration was 100 ppm.

Further, these speeds are each expressed by the following equations.

NH4-N removal rate -dN/dt = kHzBNN
Ox -N removal rate -dn/dt = k2ZB, where, N: NH4-N concentration CI)I)m), n:
kiOx-N 9 degrees (ppm), kl; NH4-'N
Removal rate constant, k,: N0X-N removal rate constant, Z,
: MLIIES concentration (ppm).

FIG. 4 shows the results of determining the relationship between the reaction tower mixed feed ORP and 1 t kZ. In FIG. 4, marks 11 and 0 indicate NOx-N, and marks 12 and 0 indicate NH4-N, respectively. As is clear from Figure 4, 0RPO
At ~100 mV, the kl p kl value shows a maximum value, and 10
It rapidly decreases above 0 tny and below omv. The reason for this is (i) When ORP is 0 or less, free oxygen does not sufficiently permeate into the flocs of high-concentration activated sludge (10,000 ppm or more), and the nitrification function is inhibited. (!1) When the ORP is 10 rJmV or more, the amount of free oxygen that permeates becomes excessive, inhibiting the activity of the No, -N removal function, and a large amount of No2-N accumulates in the mixed solution, causing the No2 Since -N has an activity-inhibiting effect on the nitrification function, the ability to remove NH and -N may be reduced.

Therefore, it is clear that there is a limit to the ORB value as a setting range where NH4-N removal (oxidation) and NOx-N removal (reduction) coexist.In the present invention, based on the above experimental results, the ORB value is set within the range of 0 to 100 mV. It was selected as follows. By operating the reactor in this range of ORB values, 1i1H4
-Kl removal and IJ'OX-N removal can be performed simultaneously with high efficiency.

[Brief explanation of drawings]

Figure 1 is a diagram showing an example of an embodiment of the method of the present invention, Figures 2 to 4
The figure is a diagram showing the results obtained in an experiment of the present invention. Sub-agent 1) Meifuku agent Ryo Hagiwara - Figure 2 Activity inside the reaction column> 5 mud H (kg)

Claims (1)

[Claims] In a method of directly biologically treating high-concentration nitrogen-containing waste liquid, which exceeds the scope of application of the normal activated sludge method, with no dilution or extremely low dilution, NH4-N is removed in a single reaction tank under air supply, and NOx-IJ lines are removed at the same time. A wastewater treatment method characterized by setting the oxidation-reduction potential of the reaction tank liquid in the range of 0 to 100 mV (excluding DmV) in order to perform removal with high efficiency.