DEVICE AND METHOD FOR MAINTAINING STABILITY OF ANAEROBIC AMMONIUM OXIDATION (ANAMMOX) BY USING COMBINED ZEOLITE FILLER TO RESIST WATER QUALITY FLUCTUATIONS

Abstract

A device and a method for maintaining the stability of anaerobic ammonium oxidation (anammox) by using a combined zeolite filler to resist water quality fluctuations are provided.

The device includes a water inlet tank, an anammox reactor, and a water outlet tank, where the anammox reactor is filled with the combined zeolite filler maintained in a state of suspension, domestic sewage enters the anammox reactor through a water inlet pump, and effluent water enters the water outlet tank through an overflow port. The device combines the physical characteristics of zeolite adsorption of ammonium with the anammox process: when the concentration of ammonium in the influent water is too high, the zeolites will temporarily store the excess ammonium adsorbed; when the concentration of nitrite in the influent water is too high, the zeolites are capable to release the stored ammonium into a liquid phase through balanced adsorption desorption.

Claims

1. A device for maintaining a stability of an anammox by using a combined zeolite filler to resist water quality fluctuations, comprising a water inlet tank, an anammox reactor, and a water outlet tank, wherein the water inlet tank is provided with a heating rod and a water inlet pump; the anammox reactor is provided with a water inlet, the combined zeolite filler, an on-line pH/DO detector, a reflux inlet, a reflux pump, and an overflow port; the combined zeolite filler is provided with a polypropylene mesh spherical shell, zeolite particles, and polystyrene foams; and the water inlet tank is connected to the water inlet of the anammox reactor through the water inlet pump; and the anammox reactor is connected to the water outlet tank through the overflow port.

2. A method for maintaining the stability of the anammox by using the combined zeolite filler to resist the water quality fluctuations according to claim 1, wherein start-up and operation control steps are as follows: 2.1) start-up phase: starting the anammox reactor in a continuous-flow mode, inoculating sludge, wherein the sludge is anammox granular sludge, and controlling a concentration of the sludge in the anammox reactor at 3000-4000 mg/L; controlling a water inlet temperature of an influent water by the heating rod, within a range of 30-35? C.; and controlling a pH value within a range of 7-8 and a hydraulic retention time of 10-15 h; wherein the influent water has a nitrite concentration of 60-90 mg/L and an ammonium concentration of 50-70 mg/L, and a ratio of the nitrite concentration and the ammonium concentration is controlled at 1.32; and the influent water comprises the following substances: 60-90 mgN/L of NaNO.sub.2, 50-70 mgN/L of NH.sub.4Cl, 0.5-1.0 g/L of NaHCO.sub.3, 20-40 mg/L of KH.sub.2PO.sub.3, 100-300 mg/L of CaCl.sub.2.Math.2H.sub.2O, 100-300 mg/L of MgSO.sub.4.Math.2H.sub.2O, 0.5-1.0 mL/L of a first trace element solution, and 0.5-1.0 mL/L of a second trace element solution, wherein mL is a unit of a volume of an added first trace element solution or an added second trace element solution, L is a unit of a total volume of the influent water, and the above concentrations are the final concentrations of various substances in the influent water; and preparing the first trace element solution or the second trace element solution based on the following matrix ratio with water as a solvent, wherein the first trace element solution comprises: 6-7 g/L of EDTA.Math.2Na, and 5-6 g/L of FeSO.sub.4.Math.7H.sub.2O, and the second trace element solution comprises: 18-20 mg/L of EDTA.Math.2Na, 0.01-0.02 mg/L of H.sub.3BO.sub.3, 0.4-0.5 mg/L of ZnSO.sub.4.Math.7H.sub.2O, 0.2-0.3 mg/L of CoCl.sub.2.Math.6H.sub.2O, 0.2-0.3 mg/L of CuSO.sub.4.Math.5H.sub.2O, 0.9-1.0 mg/L of MnCl.sub.2.Math.4H.sub.2O, 0.1-0.2 mg/L of NiCl.sub.2.Math.6H.sub.2O, and 0.2-0.3 mg/L of NaMoO.sub.4.Math.2H.sub.2O; after stripping for a deaeration by nitrogen, the influent water continuously flows into the anammox reactor through the water inlet pump; adding the combined zeolite filler inside the anammox reactor, wherein a dosing ratio is 30-40%, and an inside of the polypropylene mesh spherical shell is filled with the zeolite particles with a diameter of 3-8 mm and the polystyrene foams, the diameter of each of the zeolite particles and a diameter of each of the polystyrene foams are larger than a mesh diameter of the polypropylene mesh spherical shell to make the zeolite particles and the polystyrene foams not fall out, and the zeolite particles and the polystyrene foams are filled at a volume ratio of 1:1-1:2 for suspending inside the anammox reactor; controlling a reflux ratio at 300-500% through the reflux pump, to prevent the combined zeolite filler from settling; when the concentrations of nitrite and ammonium in an effluent water are both less than 5 mg/L, and a removal rate of a total nitrogen stably remains at above 70% for more than 14 days, wherein the anammox reactor is started successfully; 2.2) operation phase: 2.2.1) simulated water quality fluctuation phase: controlling the water inlet temperature of the influent water within the range of 30-35? C. through the heating rod; and controlling the pH value within the range of 7-8 and the hydraulic retention time of 10-15 h; wherein the nitrite concentration and the ammonium concentration in the influent water fluctuate at 30-70 mg/L, and every two hydraulic retention times constitute a cycle: the nitrite concentration in the influent water in a first hydraulic retention time is 30-50 mg/L, and the ammonium concentration in the influent water in the first hydraulic retention time is 50-70 mg/L; the nitrite concentration in the influent water in a second hydraulic retention time is 50-70 mg/L, and the ammonium concentration in the influent water in the second hydraulic retention time is 30-50 mg/L; the influent water comprises the following substances: 30-70 mgN/L of NaNO.sub.2, 30-70 mgN/L of NH.sub.4Cl, 0.5-1.0 g/L of NaHCO.sub.3, 20-40 mg/L of KH.sub.2PO.sub.3, 100-300 mg/L of CaCl.sub.2.Math.2H.sub.2O, 100-300 mg/L of MgSO.sub.4.Math.2H.sub.2O, 0.5-1.0 mL/L of the first trace element solution, and 0.5-1.0 mL/L of the second trace element solution, wherein mL is the unit of the volume of the added first trace element solution or the added second trace element solution, L is the unit of the total volume of the influent water, and the above concentrations are the final concentrations of the various substances in the influent water; preparing the first trace element solution or the second trace element solution based on the following matrix ratio with water as the solvent, wherein the first trace element solution comprises: 6-7 g/L of EDTA.Math.2Na, and 5-6 g/L of FeSO.sub.4.Math.7H.sub.2O; the second trace element solution comprises: 18-20 mg/L of EDTA.Math.2Na, 0.01-0.02 mg/L of H.sub.3BO.sub.3, 0.4-0.5 mg/L of ZnSO.sub.4.Math.7H.sub.2O, 0.2-0.3 mg/L of CoCl.sub.2.Math.6H.sub.2O, 0.2-0.3 mg/L of CuSO.sub.4.Math.5H.sub.2O, 0.9-1.0 mg/L of MnCl.sub.2.Math.4H.sub.2O, 0.1-0.2 mg/L of NiCl.sub.2.Math.6H.sub.2O, and 0.2-0.3 mg/L of NaMoO.sub.4.Math.2H.sub.2O; after stripping for the deaeration by nitrogen, the influent water continuously flows into the anammox reactor through the water inlet pump; controlling the reflux ratio at 300-500% through the reflux pump, to prevent the combined zeolite filler from settling; 2.2.2) actual water quality fluctuation phase: the influent water of the anammox reactor is a mixture of domestic sewage and nitrite; controlling the water inlet temperature of the influent water within the range of 30-35? C. through the heating rod; and controlling the pH value within the range of 7-8 and the hydraulic retention time of 10-15 h; wherein the nitrite concentration in the influent water is 30-70 mg/L, the ammonium concentration in the influent water is 30-70 mg/L, and the ratio of the nitrite concentration and the ammonium concentration fluctuates irregularly at 0.5-2.3; after stripping for the deaeration by nitrogen, the influent water continuously flows into the anammox reactor through the water inlet pump; and controlling the reflux ratio at 300-500% through the reflux pump, to prevent the combined zeolite filler from settling.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 is a schematic diagram of the structure of a device for maintaining the stability of anaerobic ammonium oxidation (anammox) by using a combined zeolite filler to resist water quality fluctuations:

[0025] In FIG. 1: 1-water inlet tank, 2-anammox reactor, 3-water outlet tank; 1.1-heating rod; 1.2-water inlet pump; 2.1-water inlet, 2.2-combined zeolite filler, 2.3-online pH/DO detector, 2.4-reflux inlet, 2.5-reflux pump, and 2.6-overflow port;

[0026] FIG. 2 is a schematic diagram of the combined zeolite filler. In FIG. 2: 2.2.1-polypropylene mesh spherical shell, 2.2.2-zeolite particles, and 2.2.3-polystyrene foams.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0028] 1. As shown in FIG. 1, a device for maintaining the stability of anammox by using a combined zeolite filler to resist water quality fluctuations includes a water inlet tank (1), an anammox reactor (2), and a water outlet tank (3); the water inlet tank (1) is provided with a heating rod (1.1) and a water inlet pump (1.2); the anammox reactor (2) is provided with a water inlet (2.1), a combined zeolite filler (2.2), an on-line pH/DO detector (2.3), a reflux inlet (2.4), a reflux pump (2.5), and an overflow port (2.6). The combined zeolite filler (2.2) is provided with a polypropylene mesh spherical shell (2.2.1), zeolite particles (2.2.2), and polystyrene foams (2.2.3); [0029] experimental device connection: the water inlet tank (1) is connected with the water inlet (2.1) of the anammox reactor (2) through the water inlet pump (1.2); the anammox reactor (2) is connected with the water outlet tank (3) through the overflow port (2.6);

[0030] 2. specific operation as follows: [0031] 2.1) start-up phase: [0032] the anammox reactor is started in a continuous-flow mode, the inoculated sludge is anammox granular sludge, and the concentration of sludge in the reactor is controlled at 3000?300 mg/L; the heating rod controls the water inlet temperature at 32? C.; the pH value falls within a range of 7.5?0.5; the hydraulic retention time is 10 h; the influent water has a nitrite concentration of 70 mg/L and an ammonium concentration of 50 mg/L; the influent water is specifically composed of the following substances: 70 mgN/L of NaNO, 50 mgN/L of NH.sub.4Cl, 0.5 g/L of NaHCO.sub.3, 30 mg/L of KH.sub.2PO.sub.3, 300 mg/L of CaCl.sub.2.Math.2H.sub.2O, 300 mg/L of MgSO.sub.4.Math.2H.sub.2O, 1.0 mL/L of a trace element I solution, and 1.0 mL/L of a trace element II solution, where mL is a unit of the volume of the added trace element I solution or the trace element II solution, L is a unit of the total volume of the influent water, and the above concentrations are the final concentrations of various substances in the influent water; the trace element I solution or the trace element II solution is prepared based on the following matrix ratio with water as a solvent, and the trace element I solution includes: 6.4 g/L of EDTA.Math.2Na, and 5.0 g/L of FeSO.sub.4.Math.7H.sub.2O; the trace element II solution includes: 19.11 mg/L of EDTA.Math.2Na, 0.014 mg/L of H.sub.3BO.sub.3, 0.43 mg/L of ZnSO.sub.4.Math.7H.sub.2O, 0.24 mg/L of CoCl.sub.2.Math.6H.sub.2O, 0.25 mg/L of CuSO.sub.4.Math.5H.sub.2O, 0.99 mg/L of MnCl.sub.2.Math.4H.sub.2O, 0.15 mg/L of NiCl.sub.2.Math.6H.sub.2O, and 0.22 mg/L of NaMoO.sub.4.Math.2H.sub.2O; after stripping for deaeration by nitrogen, the influent water continuously flows into the anammox reactor through a water inlet pump; the combined zeolite filler is added inside the reactor, the dosing ratio is 40%, and the inside of the polypropylene mesh spherical shell is filled with the zeolite particles with a diameter of 4 mm and the polystyrene foams, the diameters of the two are larger than the mesh diameter of the spherical shell, so that the zeolite particles and the polystyrene foams will not fall out, and the zeolite particles and the polystyrene foams are filled at a volume ratio of 1:1 to ensure that they can be suspended inside the reactor; the reflux pump controls the reflux ratio at 500%, thus preventing the combined zeolite filler from settling; and after 15 days of operation, when the concentrations of nitrite and ammonium in the effluent water are both less than 5 mg/L, and the removal rate of total nitrogen stably remains at above 70%, it indicates that the anammox reactor has been started successfully. [0033] 2.2) operation phase: [0034] 2.2.1) simulated water quality fluctuation phase: the heating rod controls the water inlet temperature at 32? C.; the pH value falls within a range of 7.5?0.5; the hydraulic retention time is 10 h; the influent water includes nitrite and ammonium whose concentrations fluctuate at 30-70 mg/L, and every two times of hydraulic retention constitutes a cycle: the concentration of nitrite in the influent water in the first hydraulic retention time is 30 mg/L, and the concentration of ammonium therein is 70 mg/L, at this time, relatively excessive ammonium will be adsorbed by zeolites; the concentration of nitrite in the influent water in the second hydraulic retention time is 70 mg/L, and the concentration of ammonium therein is 30 mg/L, in this case, the nitrite is relatively surplus, and the zeolites desorb the ammonium adsorbed in the previous cycle into a liquid phase, thereby providing a substrate for the growth of anammox bacteria; except for nitrite and ammonium in the influent water that are changed in concentrations as above, the other substrates remain unchanged, including: 0.5 g/L of NaHCO.sub.3, 30 mg/L of KH.sub.2PO.sub.3, 300 mg/L of CaCl.sub.2.Math.2H.sub.2O, 300 mg/L of MgSO.sub.4.Math.2H.sub.2O, 1.0 mL/L of a trace element I solution, and 1.0 mL/L of a trace element II solution, where mL is a unit of the volume of the added trace element I solution or the trace element II solution, L is a unit of the total volume of the influent water, and the above concentrations are the final concentrations of various substances in the influent water; the trace element I solution or the trace element II solution is prepared based on the following matrix ratio with water as a solvent, and the trace element I solution includes: 6.4 g/L of EDTA.Math.2Na, and 5.0 g/L of FeSO.sub.4.Math.7H.sub.2O; the trace element II solution includes: 19.11 mg/L of EDTA.Math.2Na, 0.014 mg/L of H.sub.3BO.sub.3, 0.43 mg/L of ZnSO.sub.4.Math.7H.sub.2O, 0.24 mg/L of CoCl.sub.2.Math.6H.sub.2O, 0.25 mg/L of CuSO.sub.4.Math.5H.sub.2O, 0.99 mg/L of MnCl.sub.2.Math.4H.sub.2O, 0.15 mg/L of NiCl.sub.2.Math.6H.sub.2O, and 0.22 mg/L of NaMoO.sub.4.Math.2H.sub.2O; after stripping for deaeration by nitrogen, the influent water continuously flows into the anammox reactor through a water inlet pump; the reflux pump controls the reflux ratio at 500%, thus preventing the combined zeolite filler from settling; [0035] 2.2.2) actual water quality fluctuation phase: the influent water of the anammox reactor is a mixture of domestic sewage and nitrite, and the domestic sewage is taken from the family dormitory building of Beijing University of Technology; the heating rod controls the water inlet temperature at 32? C.; the pH value falls within a range of 7.5?0.5; the hydraulic retention time is 10 h; the concentration of nitrite in the influent water is 30-70 mg/L, the concentration of ammonium therein is 30-70 mg/L, and the ratio of the two fluctuates irregularly at 0.5-2.3; after stripping for deaeration by nitrogen, the influent water continuously flows into the anammox reactor through a water inlet pump; the reflux pump controls the reflux ratio at 500%, thus preventing the combined zeolite filler from settling. According to the same principle, zeolites can maintain a relatively stable denitrification efficiency in spite of fluctuating influent substrate ratios, and ammonium and nitrite in the effluent water still maintain a relatively low concentration. After 39 days of operation, the denitrification efficiency of the system reaches and remains at 75%, indicating that efficient denitrification has been achieved through anammox.