JPS5959294A - Method for controlling amount of sludge - Google Patents

Abstract

PURPOSE:To stably and properly control the concentration of suspended matter, by calculating the amount of sludge to be returned and the amount of excess sludge to be withdrawn necessary for properly controlling the concentration of suspended matter, and controlling the amount of sludge to be returned on the basis of said withdrawal amount. CONSTITUTION:The first measuring tank 2, an aeration tank 3 and a precipitation tank 4 are sequentially attached in an inflow pipe 1 from its upper stream side, one side of a sludge-receiving chamber 5 for withdrawing sludge through the bottom of the precipitation tank 4 is connected to a pump 6, the second measuring tank 7 and the aeration tank 3 through a sludge-returning pipe 8 at the downstream side of said precipitation tank 4, and the other side of the sludge-returning chamber 5 is connected to a pipe 9 for transferring excess sludge. The detecting part 13a of a densitometer 13 for measuring the concentration of suspended matter in inflow water is provided inside the first measuring tank 2, the third measuring tank 10 is provided at a position near the outlet side of the aeration tank 3, and the detecting part 11a of an MLSS densitometer 11 is attached to the interior. An indicator 15 is constituted with the densitometer 13 for measuring the concentration of suspended matter in inflow water, the MLSS densitometer 11 and an RS densitometer 12.

Description

Detailed Description of the Invention The present invention relates to a method for controlling the amount of sludge in the activated sludge method. ), and maintaining the activated sludge concentration (hereinafter referred to as MLS8) in the tank at a constant value is an important requirement for management operations. Therefore, if the dissolved oxygen concentration is appropriately controlled, all that is left to do is to appropriately manage the IAL S B concentration in the aeration tank and adjust the amount of return sludge (hereinafter referred to as R6) necessary for this purpose. Therefore, the setting of the RB amount is an important operating condition for keeping the MLEIS concentration to be maintained constant in the sludge-loaded aeration tank, which is a processing condition of the activated sludge method. For this reason, a method of supplying RB in an amount appropriate to the amount of inflow water has been adopted, but with this method, it is impossible to maintain the MLS'S concentration constant unless the Re concentration is always constant. It is difficult, and unless excess sludge (hereinafter referred to as WS) produced as a by-product as activated sludge flocs proliferates in the aeration tank is removed one by one, the MLSS concentration in the aeration tank will increase and the sludge load will increase. Proper management becomes even more h=. Also, the M L
An increase of 88% does not only increase the accumulation of sludge in the settling tank, but also causes anaerobically putrid sludge to float to the surface, and has a negative impact on the effectiveness of sludge dewatering treatment. It will also happen. Moreover, the amount of WS produced depends on the type of wastewater, BOD
υ varies depending on stream temperature, MLSS dedication, and ventilation rate, and is also affected by water temperature.

For this reason, there is a drawback in that the amount of by-products of the removed BOD and wastewater flowing into the aeration shaft must be constantly checked, and complicated operations such as pulling out the wastewater thereby required.

In order to objectively understand that the activated sludge can fully perform its functions under such conditions, the present invention provides the following information regarding the control MLSS concentration in the aeration tank, which is indicated as a control indicator.
Aeration @Measure the SS amount of inflow water, the current MLSS concentration in the aeration tank, and the return sludge (R8) concentration, and based on the measured values, calculate the ratio and surplus sludge (hereinafter referred to as WS). The system performs arithmetic processing using the numerical values obtained from the measurement results to obtain each setting value, which is used as a guideline for operation.The configuration is as follows: an automatic measuring device that measures the concentration of suspended solids in inflowing raw sewage, the concentration of returned sludge returned to the aeration tank from the settling tank communicating with the aeration tank, and the concentration of suspended solids in the mixed liquid in the aeration tank; It consists of a recorder that records the measured value based on the output signal from this measuring device, and a calculation formula given from the measured value of the automatic measuring device to calculate the signal of the required solid substance. Calculate the amount of returned sludge and the amount of excess sludge removed that are necessary to properly control the suspended solids concentration, which is important as an operating condition for the operation of the It is characterized by the fact that the concentration of suspended solids is always controlled at an appropriate level by determining and appropriate operation.Here,
The amount of solids refers to the amount of managed MLS, S, RE3 amount, ws amount, s
This indicates the amount of s removal.

In carrying out automatic rectangle measurement of dense storms, the present invention employs the L-logical measurement method, and employs a scattered transmitted light method designed based on Lambert Beer's law. When performing measurements using this method, differences may be observed in the measured concentration values (due to differences in particle size, particle coloring, etc.). For this reason/θ, in the present invention, the target wastewater is sampled in advance and the factory wastewater test method J-K5-K
Manual analysis shall be conducted in accordance with the gravimetric measurement method for suspended substances in 1012.10.2, and the value obtained when the concentration is changed shall be compared and corrected with the value indicated on the densitometer.

To explain the embodiment of the present invention with reference to the drawings, an inflow pipe (1)
Inside, there is a 2-l measuring tank (2) and aeration 41! iI < 3) and a settling tank (4) are installed sequentially from the upstream side, and a sludge storage chamber is provided on the downstream side of this settling tank (4) to pull out sludge from the bottom of the settling tank [4]. The negative side of (5) is the pump (
6), the second measuring ridge (7), and the aeration tank (3) are connected by a sludge return pipe (8), and the excess sludge transfer pipe (9) is connected to the other side of the sludge storage chamber (5). It is. First measurement tank (2)
Inside is an inflow water suspended solids (hereinafter referred to as Ni SS) concentration meter αj
A detection unit (13α) is installed, an eighth measurement tank αO is installed near the outlet side of the aeration tank (3), and an MLSS
Detection of concentration αD 11μ (11(Z))

In addition, a second measurement tank (7) installed in the middle of the return sludge pipe (8)
The detection part (12α) of the R8 densitometer (6) is installed inside. (to) is an indicator consisting of the influent water suspended solids (nee SS) concentration meter 03, M L 8.8 concentration meter 1 round, and R8 concentration meter (c), and the conversion pilt built in this indicator 09
(not shown), the concentration at that time is indicated to each indicator, and this signal is further transmitted to the recorder 0Q and the arithmetic unit α power. This recorder uses a pen mechanism to continuously record the measured values at 8 locations, while the arithmetic unit α calculates the R9 amount (rate) and the WS withdrawal amount based on the set arithmetic formula. It is something to do.

Next, calculations are performed based on the "sludge ordinance" which is the standard of calculation. This is because the time required for suspended matter analysis is shorter than that for BOD-MLSS loading, so data can be obtained in a short period of time, and the sludge age is adjusted by increasing or decreasing the Mn3Si degree in the same way as the BOD-MLS8 loading adjustment. If the sludge order is kept within the standard, when the BOD-MLBE3 shellfish values are almost equal to each other, it is possible to obtain the load amount in a shorter time than by measuring the BOD by obtaining the sludge order. It is.

The functions of the calculator are the items that are manually memorized in advance (inflow water volume (Ql: m, aeration tank volume (■: m3, MLSS concentration to be controlled 2m♂μ), and the items sent from the automatic measuring device). Calculation is performed using the following calculation formula based on the measured value of .

Incidentally, when a flow meter is provided in the middle of the inflow pipe (1), θ1f and the amount of water inflow Q are input directly to the computer through the totalizer.

Amount of returned sludge (Rs): m”, 41 MLSS (my/j-)-v Ying Hoho (my%')-□
□-Karichin-Keturu-kiri-aki (♂/13: 9-side ♂rib (my/JL)-MLSS (my/l) Excess sludge extraction amount (ws): m"The numerical value obtained in this way Based on this, the amount of sludge to be returned is adjusted, excess sludge is pulled out, and the MLSSg treatment in the warm tank is performed.

As described above, the present invention quickly obtains numerical values that satisfy the conditions necessary for engine operation by combining an automatic measuring device, a recorder, and a computing device that corresponds to the formula specified as a control indicator. In order to ensure that the activated sludge can fully perform its functions, set values for the amount of returned sludge and the amount of surplus sludge can be determined by performing inverse arithmetic processing using the numerical values obtained from the measurement results.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall flowchart, FIG. 2.8 is an explanatory diagram showing an outline of the arithmetic device, and FIG. 4 is a schematic diagram of the device. (3) is an aeration tank, (4) is a settling tank, (5) is a sludge storage chamber, (8) is a sludge return pipe, (9) is an excess sludge transfer pipe, α0
is the MLSS concentration meter, bottle a is the return sludge concentration meter, αj is the inflow water suspended solids concentration meter, (19 is the indicator, α0 is the recorder, and α force is the calculation device. Patent applicant: Hide Kitayama, attorney) 1) Dai Kazuo 11th 4th Kyo 8. . ~1゜4,34 11

Claims (1)

[Claims] In a sewage treatment system using the activated sludge method, the concentration of suspended solids in the raw sewage flowing into the aeration tank, the concentration of returned sludge returned to the aeration tank from the settling tank communicating with the aeration tank, and the suspension of the mixed liquid in the aeration tank are determined. An automatic measuring device that measures the solid matter concentration, a recorder that records the measured value based on the output signal from this measuring device, and a calculation formula given from the measured value of the automatic measurement 4M to calculate the required amount of solid matter. ti from the arithmetic unit
c D. Calculate the amount of return sludge and amount of excess sludge necessary to manage the appropriate amount of suspended solids, which is an important operating condition for activated sludge treatment, and adjust and adjust the amount of return sludge based on these values. A method for controlling the amount of sludge whose purpose is to determine the amount of excess sludge to be extracted and to constantly manage the concentration of suspended solids by appropriate operation.