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The subject of the reduction and precipitation - stripping - struvite (MAP) \The entire wastewater treatment process, as well as the various factors affecting the system. The Xichang Emperor Xin Vanadium and Titanium Industry Co., Ltd. is an enterprise production V205 its production wastewater containing pollutants, heavy metals V, Cr, and NH3-N. On the basis of the findings of the laboratory tests, a full investigation of the situation on the spot, as well as considering the technical feasibility and economic reasonableness under the premise of using the two-step method for purification of wastewater, the first reduction and precipitation to In addition to the V and Cr in the wastewater reuse after stripping-MAP treatment to remove heavy metals V, Cr NH3-N wastewater V205 wastewater pollutant content to meet emission and reuse requirements. Experimental data indicate that the wastewater pH, reducing agent, and its amount, reaction time, reaction temperature, and the precipitation reaction the pH value is the main factors of the impact reduction precipitation method of Cr6 removal efficiency. In the wastewater water temperature ≥ 40 ° C, the reduction reaction pH value ≤ 2.0 and guarantee the reduction reaction the wastewater pH ≤ 3.0, NaHSO3 as reducing agent, the amount of NaHS03 dosage is about 1.2 times the theoretical amount, the reaction time is ≥ 10 min, the precipitation reaction The best water temperature ≤ 40 ℃ conditions, wastewater treatment effluent of Cr6, total chromium and total vanadium concentration (GB8978-1996) can be reduced to the integrated wastewater discharge following a standard value. Affect the stripping method of the main factors of the wastewater removal efficiency of NH3-N: pH, water temperature, gas-liquid ratio and stripping time. The wastewater water temperature is 30 to 40 ° C, pH value of 10.5-11.0 gas-liquid ratio of 3000:1, stripping 30 min under the conditions of the pre-removal of NH3-N wastewater stripping effluent NH3-N and then by MAP to In addition to NH3-N; affect MAP of the main factors of the removal efficiency of NH3-N: molar ratio, pH value, temperature, precipitation dosage is reaction time. Wastewater water temperature of 35-40 ° C, pH value of 8.5-9.0, precipitating agent dosage n (Mg2): n (PO43-): n (NH4) 1.0: (1.0-1.025): 1.0 to precipitate 30 min under the conditions of removal of NH3-N, effluent NH3-N concentration can be reduced to the Integrated Wastewater Discharge (GB8978-1996) with a standard value of 15 mg / L or less. Applied research results show that the parameters of laboratory studies, V205 wastewater Cr6, total chromium, total vanadium and NH3-N removal rate was 99.93%, 99.87%, 99.30%, 98.72%. SS process is removed out of the water, the average concentration of 14.5 mg / L. Water by biochemical Tong biochemical, CODcr and phosphorus cleared away, the average effluent concentration of 37.5 mg / L and 0.16 mg / L, respectively, can be used as a water reuse or discharge standards. Restore precipitated the removal of heavy metals V, Cr with simple equipment, low investment, small footprint, easy operation and management, mixed wastewater tractable, good results, and adaptable to changes in water quality; stripping method deaminase with less investment, low running costs, the process is simple, easy transformation; the MAP law process is simple, low investment in equipment, less power consumption, convenient operation running, high ammonia removal efficiency, the reaction product of MAP versatile. Therefore, reduction and precipitation - stripping-MAP \The topics for the reduction and precipitation - stripping-MAP method to remove heavy metals V, Cr, and purification of high concentrations of NH3-N wastewater engineering design to provide theoretical guidance and design based on V2O5 production wastewater.
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