Papers by Keyword: Oxidation-Reduction Potential (ORP)

Abstract: A purpose of the present study is to derive optimum study factors for removal of heavy metals using combined alternating current electric/magnetic field and electric membranes for the area contaminated with heavy metals in soil or underground water. ORP (Oxidation Reduction Potential) analysis was conducted to determine an intensity of tendency for oxidation or reduction of the samples contaminated with heavy metals, and electrical membrane treatment was used with adjustment of concentrations and voltages of liquid electrode (Na₂SO₄) to derive a high removal rate. Removal constants were analyzed to be 0.0417, 0.119, 0.1594 when the voltages were 5V, 10V, 15V, respectively, and treatment efficiency was shown to increase as the liquid electrode concentration was increased. Keywords: heavy metals, electric/magnetic field, ORP, electrical membrane

Abstract: The pilot-scale Anoxic-Anaerobic-Microaerobic-Aerobic (A2O2) biological nitrogen removal process was used to treat the wastewater from nitrogenous fertilizer production with C/N ratio of 1~2. Batch tests were conducted to investigate the patial nitrification using the activated sludge from the microaerobic tank rich in nitrite bacteria as the experimental object. Results showed that 95% removal efficiency of NH3-N could be obtained with the HRT of 30 h. The SVI affected the NH3-N removal rate and the optimal SVI was 106 mL/g. The ORP was well correlated with the logarithm of NH3-N concentration with the linear regression equation of y=-57.233x+3.308. Moreover, the kinetic model for partial nitrification was determined as v=4.762s/(9.86+s).

Abstract: The biological phosphorus (P) removal characteristics of a full-scale Unitank wastewater treatment plant (WWTP) were investigated by field survey, model analysis and sludge P content determination. In the Unitank WWTP, oxidation-reduction potential (ORP) reached the lowest value of -17 mV and the highest value of 130 mV at the end of anoxic/anaerobic stage and aerobic stage, respectively. The anaerobic P release process could be fitted by first-order kinetics with rate constant of 3.52 h^-1, while the maximum aerobic P uptake rate was 3.31 mgP/(L•h). The measured sludge P content in the Shidongkou WWTP was 15.4±2.1 mgP/gSS, significantly lower than that in full-scale AAO WWTPs.

Abstract: Abstract. Hydrogen sulfide in biogas is one of the most obstructive factors on utilization of biogas as fuel gas. At present, a domestic desulfurizing process of biogas in wide-spead use is the ferric oxide process. But this process has its disadvantages: the high cost and difficult regeneration of the desulfurizer, the secondery pollution the process caused. As a new technique, the bio-desulfurization of biogas has drawn more and more attention recently. This dissertation, with the experience of engineering abroad bio-desulfurization, is focused on providing a clue or a reference for the research and application of this technique in the future.

Abstract: Sequencing batch biofim reactor (SBBR) can remove nitrogen by simultaneous nitrification and denitrification in the biofilm. Based on the relationship between the degradation of COD, NH3-N and ΣN in wastewater and the variation of DO, ORP and pH, the results showed that when DO and ORP rapidly increased and reached a platform (DO and ORP turning point) and pH value rapidly decreased and approached the lowest value (pH turning point), the NH₃-N and ΣN reduced to minimum. Utilizing DO, ORP and pH turning points as on-line controlling points to stop aeration ensured NH₃-N completely removed and the lowest ΣN. The effect control of aeration time could save energy.

Abstract: On the basis of a large number of continuous monitoring experiments for the five-line salinity of seawater, and the uncertainty of natural seawater oxidation reduction potential (ORP) is 2.2mV, the effect of seawater salinity on the equilibrium time of ORP is studied qualitatively and quantitatively. The results indicated that the greater the salinity, the longer the time of reaching to ORP equilibrium value, the longer the equilibrium time of the seawater ORP value. It is showed that the ORP equilibrium value was obtained at 30minutes, 90minutes, 120minutes, 240minutes and 300minutes from seawater with salinity as 5,20,30,35 and 40, respectively, and the equilibrium time was more than 12 hours. Accuracy and stability of the equilibrium time of seawater ORP value under different salinity can provide technical support for metrological verification of ORP sensor.

Abstract: Choose three kinds of clean drinking water distilled water, tap water, mineral water for the object, study the impact of magnetization on water’s conductivity, pH value, ORP and the solubility of insoluble salts by experiment of magnetic field intensity 500mT and different time, the results showed that magnetic treatment can improve the conductivity, pH of three kinds of water samples, lower ORP value, and has a certain significance on human health, but it is limited in improve the solubility of insoluble salts with the characterization of calcium carbonate.

Abstract: Drinking water needs to retain all minerals such as calcium, magnesium, potassium and sodium to make body balance. It is such minerals that makes drinking water weakly alkaline. The pH value of drinking water between 7.2 and 8.0 is the best. The ion material can improve pH value and ORP of drinking water which is processed from a variety of natural polarity mineral materials and multi-functional healthy ceramic material.

Abstract: An evaluation of healthy living water was studied. The oxidation-reduction potential (ORP) and pH values of spring in the longevity village, activated water, tap water were investigated in the paper. It was found that ORP was related to the longevity closely，and an evaluation method based ORP of healthy living water was provided. The research indicated that the evaluation was true of healthy food as well.

Abstract: Spent foundry sand (SFS) from cast iron industry mixed with loess was characterized to recycle spent foundry sand as ceramic support materials. Since SFS mostly consists of sand including binding agents and residue [1], it was used as permeable media, and loess, which has highly adsorptive and reactive properties, was used as support materials Leaching tests such as Korean Leaching Test (KLT) and TCLP (Toxicity Characteristics Leaching Procedure) showed that spent foundry sands from cast iron industry were not hazardous. Turbidity in furan sand was much higher than that in other sands, and turbidity was almost not changed with increasing amount of loess. The order of ORP (oxidation-reduction potential) in spent foundry sands was green sand > furan sand > CO2 sand. ORP was decreased with the amount of sand in furan sand and CO2 sand but was increased with the amount of sand in green sand. Hence, mixture of SFS and loess can be used as ceramic support materials with reductive or oxidative capability.