Advanced oxidation process of degrading nonsteroidal anti-inflammatory drugs in sewage by UV persulfate

Patent metadata

Field	Value
Publication number	US-10233103-B2
Application number	US-201715626126-A
Country	US
Kind code	B2
Filing date	Jun 18, 2017
Priority date	Mar 14, 2017
Publication date	Mar 19, 2019
Grant date	Mar 19, 2019

Abstract

The present invention discloses an advanced oxidation process of degrading nonsteroidal anti-inflammatory drugs in sewage by UV persulfate. The sewage flows to a secondary sedimentation tank by gravity, and sediments are precipitated and separated. Na 2 S 2 O 8 solution is added therein, and a UV lamp is opened. Effluent result is analyzed after photooxidation. The sewage is transferred into a contact disinfection pool to react with ClO 2 before discharging safely. The present invention uses a UV-based advanced oxidation process, which can effectively remove the nonsteroidal anti-inflammatory drugs in sewage, meets the requirements of sewage discharging, and decreases the environmental risk of nonsteroidal anti-inflammatory drugs. The method has some advantages such as simple equipments, easy operation, reasonable economy, as well as efficient treatment effect and high stability.

First claim

We claim:

1. An advanced oxidation process of degrading nonsteroidal antiinflammatory drugs in sewage by UV persulfate, characterized in that it mainly comprises comprising the steps of:
1) separating supernatant from sediments from the sewage by settling and precipitating the sediments in a secondary sedimentary tank by gravity;
2) detecting and recording concentration of the nonsteroidal anti-inflammatory drugs remaining in the supernatant;
3) adding a NaS 2 O 8 solution with mass concentration of 50-70% into the supernatant, forming a reaction solution, wherein the molar ratio of NaS 2 O 8 and nonsteroidal anti-inflammatory drugs in the reaction solution is from 1:1 to 100:1;
4) transferring the reaction solution to an optical reactor for reacting, irradiating the reaction solution for 5-10 mins with UV light having a working power of 22 Watt, stirring the reaction solution,
5) analyzing the concentration of nonsteroidal anti-inflammatory drugs in the reaction solution after the step 4) using high performance liquid chromatography mass spectrometry (UPLC-MS), and calculating the drug removal rate and setting up dynamic simulation, and
6) transferring the reaction solution into a contact disinfection tank to react with ClO 2 for disinfecting before discharging therefrom.

2. The advanced oxidation process of degrading nonsteroidal anti-inflammatory drugs in sewage according to claim 1 , characterized in that the secondary sedimentation tank is a vertical sedimentation tank with circular section, and the sewage flows from top to bottom with velocity of 15-25 mm/s, disposing spiral baffles at the bottom to distribute the sewage uniformly with rising speed of 0.6-0.8 mm/s at water passing section and settling time of 1.5-2.5 h; suspended solids sink into a cone sludge bucket, and clean water overflow from all around the bucket along a overflow weir, disposing baffles and scum tank above the weir to intercept scum; and disposing a sludge pipe with diameter of 300-400 mm near the tank wall, and discharging sludge regularly by hydrostatic pressure.

3. The advanced oxidation process of degrading nonsteroidal antiinflammatory drugs in sewage according to claim 1 , characterized in that detecting method of the concentration of the nonsteroidal anti-inflammatory drugs comprises steps as follows:
1) sample extraction: sampling 500 mL water samples filtered with 0.22 pm mixed fibre membrane, and then storing the samples in a refrigerator of 4° C. for solid phase extraction and concentration detection of the nonsteroidal anti-inflammatory drugs afterward, and repeating each test three times and analyzing average values±standard deviation (SD);
2) sample purification: extracting solid phase extraction column of CNW HLB of aqueous phase (60 mg, 3 mL), i.e., organic balance column, and specific steps as follows:
a. balancing the CNW HTB column by adding 3 mL methanol;
b. washing the CNW HLB column with 3 mL pure water;
c. 50 mL water samples passing through the CNW HLB column at a flow rate of 5 ml/min;
d. washing the CNW HLB column again with 3 mL methanol (5%);
e. eluting with 6 mL methanol solution, and drying liquid nitrogen to 1 mL, and storing in a refrigerator of 4° C. until subsequent machine inspection,
3) detecting the concentration of nonsteroidal anti-inflammatory drugs by UPLC-MS: the UPLC-MS being operated in electrospray negative (ESI) mode, data acquisition being performed by multiple reaction monitoring (MRM), separation being performed using a ACQUITY UPLC BEH-C18 column (2.1*50 mm, 1.7 pm,) at 30° C. with isocratic elution, the selected mobile phase being pre-ultrasonic degassed prior to use consisting of water (A) and methanol (B) at a flow rate of 0.1 mL/min, the isocratic elution being performed by 20% A phase and 80% B phase, isocratic elution for 5 mins and injection volume being 10 pL by an auto-injector.

4. The advanced oxidation process of degrading nonsteroidal anti-inflammatory drugs in sewage according to claim 1 , characterized in that the drug removal rate of the nonsteroidal anti-inflammatory drugs equals to (1−C t /C 0 )×100%, wherein C 0 is the concentration prior to treatment, and C t is the concentration of the nonsteroidal anti-inflammatory drugs at reaction time of t, and wherein the concentration unit of the nonsteroidal anti-inflammatory drugs is ug/L.

5. The advanced oxidation process of degrading nonsteroidal anti-inflammatory drugs in sewage according to claim 1 , characterized in that the optical reactor is made of quartz glass, and a quartz sleeve is vertically disposed in the center of the optical reactor; and an ultraviolet lamp is placed in the quartz sleeve for irradiation.

6. The advanced oxidation process of degrading nonsteroidal anti-inflammatory drugs in sewage according to claim 1 , characterized in that the reaction is irradiated using an ultraviolet lamp comprising a quartz tube, wherein the ultraviolet lamp is a low pressure mercury lamp which emits monochromatic ultraviolet light of 254 nm, and the intensity of the ultraviolet light from the outer wall of the quartz tube is 1.35 mW/cm 2 .

7. The advanced oxidation process of degrading nonsteroidal anti-inflammatory drugs in sewage according to claim 1 , characterized in that a ClO 2 generator is connected with the contact disinfection tank, and the reaction with ClO 2 can disinfect and kill pathogenic microorganisms in the sewage.

Assignees

• Nanjing University Of Technology

Inventors

• Geng Jinju
• Gao Xingsheng
• Ren Hongqiang
• Xu Ke
• Zhang Yan
• Huang Hui

Classifications

• C02F1/68

  by addition of specified substances, e.g. trace elements, for ameliorating potable water (medicinal water A61K) · CPC title

• C02F2001/007

  Processes including a sedimentation step · CPC title

• C02F2209/00

  Controlling or monitoring parameters in water treatment · CPC title

• C02F2101/34

  containing oxygen · CPC title

• C02F2201/322

  Lamp arrangement · CPC title