CN-121735427-B - Emergency treatment method for impact on water quality of purified water plant of domestic sewage

Abstract

The invention provides an emergency treatment method for the impact of water quality of a purified water plant of domestic sewage, which aims at rapid judgment and intervention of sudden ammonia nitrogen/dissolved oxygen double-high phenomenon. The method comprises the steps of detecting the rising rate of ammonia nitrogen and dissolved oxygen in time, detecting the abnormal water quality change in time, determining whether oxygen supply is insufficient by adjusting aeration quantity in an initial judging stage, adding thiourea detection reagent after complexing heavy metal ions by adopting disodium ethylenediamine tetraacetate in a determining stage, determining an abnormal root through a color reaction, cutting off a polluted water source, reducing water inflow, adding sodium hypochlorite, supplementing healthy sludge and replacing part of sludge to restore microbial activity, and finally gradually restoring normal water inflow load and adjusting aeration quantity to stabilize the dissolved oxygen. The method can rapidly locate the cause of the problem and implement targeted treatment, thereby ensuring that the water plant maintains stable operation under sudden water quality impact and the effluent quality reaches the standard.

Inventors

• YUAN YUN
• ZHOU SHUNING
• CHEN ZHAN
• ZHANG CHI
• YANG YI
• ZHOU FEN
• CHEN SHIHUI
• LI JIE
• LV XIN
• XIA MENGYING
• ZHU YUNFEI
• XIE GUOJIE
• ZHANG YING
• Yu Yefan
• FANG HAO
• SHI XIAOBO
• Ba Jianjie
• ZHOU BIN
• Qin Zhongchong

Assignees

• 宁波市城市排水有限公司

Dates

Publication Date

20260512

Application Date

20260213

Claims (10)

1. 1. An emergency treatment method for the impact of the water quality of a purified water plant of domestic sewage is characterized in that, The emergency treatment method comprises the following steps: detecting the concentration change of ammonia nitrogen and dissolved oxygen in unit time, and judging the sudden ammonia nitrogen/dissolved oxygen double-high phenomenon when the ammonia nitrogen concentration is increased at the rate of 3-5 mg/L.h and the dissolved oxygen concentration is increased at the rate of 2-4 mg/L.h; S200, primarily judging, namely, adjusting aeration quantity of a biological reaction tank to improve oxygen supply, and judging that the sudden ammonia nitrogen/dissolved oxygen double-high phenomenon is not insufficient in oxygen supply but nitrifying bacteria activity is inhibited when ammonia nitrogen concentration is still continuously increased under the condition of improving oxygen supply; S300, determining, namely taking a water sample, adding a thiourea detection reagent into the water sample, and if the solution becomes haematochrome, determining that the root cause of the sudden ammonia nitrogen/dissolved oxygen double-high phenomenon is thiourea in the water inlet; s400 the emergency treatment, including, S401, checking and cutting off a water inlet source containing thiourea; S402, reducing water inflow, and adding sodium hypochlorite aqueous solution into the advanced treatment area; S403, supplementing and replacing sludge; S404, gradually recovering the water inflow load to 75% -85% of the designed value, and slowly increasing the aeration amount of the reaction tank to stabilize the concentration of dissolved oxygen at 2.5-3.5 mg/L; S500, verifying the effluent, and when the ammonia nitrogen concentration of the effluent is less than or equal to 1mg/L and the dissolved oxygen concentration is 2-4 mg/L, confirming that the emergency treatment is completed.
2. 2. The emergency treatment method according to claim 1, wherein the determining step specifically comprises the steps of S301 taking 100-500 mL of water sample, adding disodium ethylenediamine tetraacetate into the water sample, and enabling the molar ratio of the adding amount of the disodium ethylenediamine tetraacetate to the concentration of heavy metal ions in the wastewater to be 1:1.5-2.5.
3. 3. The emergency treatment method according to claim 1, wherein the thiourea detection reagent comprises 3.2-4.8 mol/L of HAc solution, 2.3-3.5% of NaNO 2 solution, 0.1-0.3 mol/L of Fe (NO 3 ) 3 solution, 0.8-1.3 mol/L of HNO 3 solution.
4. 4. The emergency processing method according to any one of claims 1 to 3, wherein the determining step further includes: S302, taking the treated water sample, placing the water sample in a colorimetric tube, adding 0.1-2.0 mL of LHAc solution, adding 0.1-2.8 mL of LNaNO 2 solution, carrying out one-time volume fixing by deionized water, and standing at room temperature for 20-40 min; S303, sequentially adding 1.0-3.5 m LFe (NO 3 ) 3 solution and 0.1-2.0 m LHNO 3 solution), carrying out secondary volume fixation by using deionized water, taking a reagent blank as a reference, shaking uniformly, and measuring the absorbance.
5. 5. The emergency treatment method according to claim 1, wherein in the step S402, the water inflow is reduced to 800-1200 m 3 /h.
6. 6. The emergency treatment method according to claim 1, wherein in the step S402, the addition concentration of the sodium hypochlorite aqueous solution is 8-15 wt%, the addition flow rate is 1800-2200 l/h, and the addition amount of the sodium hypochlorite aqueous solution relative to the sewage is 800-1200 ppm.
7. 7. The emergency treatment method according to claim 1, wherein step S403 specifically includes inoculating solid healthy sludge in the biological reaction tank, adding 20-50 mg/L sodium acetate, maintaining ph=7.5-8.0 in the biological reaction tank, and synchronously discharging excess sludge in the secondary sedimentation tank, so as to maintain the sludge concentration at 4500-6000 mg/L.
8. 8. The emergency treatment method according to claim 1, wherein a thiourea standard solution is prepared and absorbance is measured by adding the thiourea detection reagent to obtain a standard working curve.
9. 9. The emergency treatment method according to claim 2, wherein the heavy metal ion concentration is measured by atomic absorption spectrophotometry and/or atomic fluorescence.
10. 10. The emergency treatment method according to claim 2, wherein after the sampling in step S301, the sample is filtered through a microporous filter membrane of 0.20-0.80 μm.

Description

Emergency treatment method for impact on water quality of purified water plant of domestic sewage Technical Field The invention relates to the technical field of town sewage treatment, in particular to an emergency treatment method for the impact of the water quality of a purified water plant of domestic sewage. Background In the running process of a domestic sewage purification water plant, the condition of external water quality impact is often encountered, such as the theft and drainage of industrial wastewater, the discharge of construction slurry and the influx of a large amount of pollutants caused by extreme weather conditions, such as storm, flood and the like, and the serious adverse effect is often caused on the original biochemical treatment system. In the biological treatment link, external impact can cause the damage of an activated sludge system, and after a large amount of high-concentration toxic or nondegradable pollutants enter a biological pond, the activity of microorganisms can be reduced or the large area of microorganisms can die, so that the biochemical system is crashed. In addition, the external water quality impact can also cause equipment blockage and damage, construction slurry and suspended particles easily cause deposition and blockage of an aeration system, so that the distribution of dissolved oxygen is disordered or the aeration efficiency is reduced, and meanwhile, facilities such as a membrane assembly, a pipeline and the like can be damaged due to the attachment or pollution of impurities, so that the operation resistance is increased, the energy consumption is increased and even the operation is stopped. Although some researches on the water works to deal with sudden water quality pollution exist in the prior art, the existing method only can lighten short-term impact influence to a certain extent, does not give out targeted effective urgent treatment measures, and cannot radically solve the problem of breakdown of a biochemical system caused by external water quality impact. Therefore, when a water plant suffers such an emergency, it is often difficult to timely recover the stability of the system, so that the quality of the effluent water continuously exceeds the standard, and the treatment efficiency is obviously reduced. Disclosure of Invention The invention provides an emergency treatment method for the impact of the water quality of a purified water plant of domestic sewage, which solves the problems that the prior art is difficult to accurately identify and cope with the sudden ammonia nitrogen/dissolved oxygen double-high phenomenon, effectively overcomes the defects of lag reaction, long recovery period and easy exceeding of the standard of the water quality when the traditional process encounters sudden toxic impact, and remarkably improves the emergency treatment capability and the water outlet stability of the purified water plant for coping with the water quality mutation. The invention provides an emergency treatment method for the impact of the water quality of a purified water plant of domestic sewage, The emergency treatment method comprises the following steps: detecting the concentration change of ammonia nitrogen and dissolved oxygen in unit time, and judging the sudden ammonia nitrogen/dissolved oxygen double-high phenomenon when the ammonia nitrogen concentration is increased at the rate of 3-5 mg/L.h and the dissolved oxygen concentration is increased at the rate of 2-4 mg/L.h; S200, primarily judging, namely, adjusting aeration quantity of a biological reaction tank to improve oxygen supply, and judging that the sudden ammonia nitrogen/dissolved oxygen double-high phenomenon is not insufficient in oxygen supply but nitrifying bacteria activity is inhibited when ammonia nitrogen concentration is still continuously increased under the condition of improving oxygen supply; S300, determining, namely taking a water sample, adding a thiourea detection reagent into the water sample, and if the solution becomes haematochrome, determining that the root cause of the sudden ammonia nitrogen/dissolved oxygen double-high phenomenon is thiourea in the water inlet; s400 the emergency treatment, including, S401, checking and cutting off a water inlet source containing thiourea; S402, reducing water inflow, and adding sodium hypochlorite aqueous solution into the advanced treatment area; S403, supplementing and replacing sludge; S404, gradually recovering the water inflow load to 75% -85% of the designed value, and slowly increasing the aeration amount of the reaction tank to stabilize the concentration of dissolved oxygen at 2.5-3.5 mg/L; S500, verifying the effluent, and when the ammonia nitrogen concentration of the effluent is less than or equal to 1mg/L and the dissolved oxygen concentration is 2-4 mg/L, confirming that the emergency treatment is completed. Preferably, the determining step specifically comprises the steps of S301 taking 100-500 mL of water s