Method for recovering nitrogen and phosphorus in sewage by electrochemical struvite crystallization

A struvite and electrochemical technology, which is applied in the field of nitrogen and phosphorus sewage treatment and resource utilization, can solve the problems of low purity, high pharmaceutical cost, and low struvite efficiency.

Active Publication Date: 2018-10-19
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve a series of technical problems such as the high cost of dosing agents, low efficiency and low purity of struvite generated by the existing struvite crystallization method for recovering nitrogen and phosphorus in sewage, and provides an electrochemical Struvite Crystallization Method for Recovering Nitrogen and Phosphorus from Sewage

Method used

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  • Method for recovering nitrogen and phosphorus in sewage by electrochemical struvite crystallization
  • Method for recovering nitrogen and phosphorus in sewage by electrochemical struvite crystallization

Examples

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Embodiment 1

[0025] Build a double-chamber electrolytic cell reactor: made of plexiglass, the shape is a cylinder, the cathode and anode chambers each occupy half of the cylinder, and the volume is 300ml respectively; the two chambers are separated by a cation exchange membrane. A ruthenium-iridium-titanium plate is used as the anode, and a 304 stainless steel mesh is used as the cathode; a 10Ω high-precision resistor is connected in series in the circuit; the Keithley2700 data acquisition system is used to monitor the voltage at both ends of the resistor to calculate the system current; an air bag with good airtightness is used Gas produced in the cathode compartment is collected. Set the anolyte to 15mM Na 2 SO 4 , the cathode chamber is 10mM (NH 4 ) 2 SO 4 and 10mM NH 4 h 2 PO 4 , the molar ratio of N and P is controlled to be 3:1, and the final NH 4 + -N is 30mM, PO 4 3--P is 10 mM. With 0.1M NaOH and 0.1MH 2 SO 4 Adjust and control the initial pH of the anolyte to 7, and...

Embodiment 2

[0027] Build a double-chamber electrolytic cell reactor: made of plexiglass, the shape is a cylinder, the cathode and anode chambers each occupy half of the cylinder, and the volume is 300ml respectively; the two chambers are separated by a cation exchange membrane. A ruthenium-iridium-titanium plate is used as the anode, and a 304 stainless steel mesh is used as the cathode; a 10Ω high-precision resistor is connected in series in the circuit; the Keithley2700 data acquisition system is used to monitor the voltage at both ends of the resistor to calculate the system current. Use an airtight air bag to collect the gas produced in the cathode chamber; set the anolyte to 15mM Na 2 SO 4 , the cathode chamber is the control PO 4 3- -P concentration is 10mM, set N:P=1:1, its corresponding NH 4 + -N concentrations were 30 mM, respectively. with 0.1M NaOH and 0.1M H 2 SO 4 Adjust and control the initial pH of the anolyte to 7, and the initial pH of the catholyte to 5. The part...

Embodiment 3

[0029] Build a double-chamber electrolytic cell reactor: made of plexiglass, the shape is a cylinder, the cathode and anode chambers each occupy half of the cylinder, and the volume is 300ml respectively; the two chambers are separated by a cation exchange membrane. A ruthenium-iridium-titanium plate is used as the anode, and a 304 stainless steel mesh is used as the cathode; a 10Ω high-precision resistor is connected in series in the circuit; the Keithley2700 data acquisition system is used to monitor the voltage at both ends of the resistor to calculate the system current; an air bag with good airtightness is used Gas produced in the cathode compartment is collected. Select 15mMNa 2 SO 4 For the anolyte, it is used to increase the conductivity of the anolyte. Catholyte is 10mM NH 4 h 2 PO 4 , 10mM (NH 4 ) 2 SO 4 Prepare the simulated wastewater and control the molar ratio of N:P to be 3:1, and the final NH 4 + -N concentration is 420mg / L, PO 4 3- -P concentration...

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Abstract

The invention discloses a method for recovering nitrogen and phosphorus in sewage by electrochemical struvite crystallization. The method is used for solving the problems of large overpotential and high magnesium source cost of existing electrochemical struvite crystallization recovery of nitrogen and phosphorus in sewage, and acidolysis of cheap magnesium mineral in an anolyte is used to significantly reduce the overpotential and reduce the cost of the magnesium source. The method is based on the conditions of acidification of the anolyte and alkalization of a catholyte, formed by electrode reactions in a dual-chamber electrolytic tank, and the magnesium mineral is added into an anode chamber to prevent preventing acidification of the anolyte and stabilize the pH value of the anolyte; andmagnesium ions released by the acidolysis of the magnesium mineral go through a cation exchange membrane and migrate to a cathode under the driving of electric field force, the migrated magnesium ions and ammonium ions and phosphate radicals in sewage in a cathode chamber undergo a crystallization reaction under alkaline conditions to form a struvite precipitate and stabilize the pH value of thecatholyte, so the purpose of simultaneously removing and recovering nitrogen and phosphorus in the sewage is achieved. The method makes the electrochemical struvite crystallization recovery of nitrogen and phosphorus in the sewage have great application and promotion values.

Description

technical field [0001] The invention discloses a method for recycling sewage nitrogen and phosphorus by electrochemical struvite crystallization, and belongs to the field of nitrogen and phosphorus-containing sewage treatment and resource utilization. Background technique [0002] Wastewater nitrogen and phosphorus recovery is a hot spot and frontier in environmental research. Nitrogen and phosphorus are not only pollutants to be removed in sewage treatment, but also fertilizer elements necessary for the growth of food crops. The eutrophication of water bodies is becoming more and more serious due to the discharge of nitrogen and phosphorus in sewage, which not only destroys the water ecosystem, but also poses a serious threat to the safety of drinking water for humans and animals; at the same time, the production of nitrogen fertilizer consumes about 2% of global energy, and phosphorus is a As an irreplaceable and non-renewable resource, the world's available phosphate rock...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/461C02F1/42C02F101/10C02F101/16
CPCC02F1/42C02F1/461C02F2101/105C02F2101/16Y02E50/30
Inventor 张志强佘璐张姣夏四清
Owner TONGJI UNIV
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