Effect of pH on Pretreatment of Sulfate-Laden Wastewater for Mixotrophic Desulfurization-Denitrification Process

2010 ◽  
Vol 113-116 ◽  
pp. 429-433
Author(s):  
Wei Li ◽  
Xiao Liang ◽  
Jian Guo Lin
Keyword(s):  
Organic Carbon ◽  
Ph Value ◽  
Removal Rate ◽  
Subsequent Treatment ◽  
Sulfate Removal ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Sulfurous Compounds ◽  
Set Up ◽  
Denitrification Process

An anaerobic attached-growth bioreactor was set up to treat wastewater rich in sulfate and organic carbon. It was the pretreatment of mixotrophic desulfurization-denitrification process. With pH decreasing from 8 to 7, the sulfate removal rate and oxidation reduction potential increased, while sulfide generating rate and effluent pH decreased. When pH value was maintained at 7.5, the removal rates of sulfate and organic carbon reached 91.5% and 90.5%, respectively. Meantime, the generating rate of sulfide reached 47.8%, which was beneficial to the subsequent treatment and to the thorough removal of sulfurous compounds. The results showed that the suitable influent pH in sulfate reduction stage for the pretreatment of desulfurization-denitrification process was 7.5.

Effect of Hydraulic Retention Time on Pretreatment of Sulfate-Laden Wastewater for Desulfurization-Denitrification Process

2010 ◽  
Vol 113-116 ◽  
pp. 536-539
Author(s):  
Wei Li ◽  
Xiao Liang ◽  
Jian Guo Lin
Keyword(s):  
Organic Carbon ◽  
Sulfate Reduction ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Removal Rate ◽  
Reduction Stage ◽  
Sulfate Removal ◽  
Carbon Sulfide ◽  
Set Up ◽  
Denitrification Process

In order to treat wastewater rich in sulfate and organic carbon, an anaerobic attached-growth bioreactor was set up. It was the pretreatment of desulfurization-denitrification process. At hydraulic retention time of 128h-6.2h, sulfate removal rate and sulfide generating rate took on initial increasing and subsequent decreasing. At hydraulic retention time of 7.7h-10.2h, the removals of sulfate and organic carbon, sulfide generating rate reached 95.79%, 80% and 58.82%, respectively. The results showed that the suitable hydraulic retention time in sulfate reduction stage for the pretreatment of desulfurization-denitrification process was 7.7h-10.2h.

Derivation of Optimum Study Factors for Samples Contaminated with Cd Using Electric/Magnetic Field and ORP

2013 ◽  
Vol 813 ◽  
pp. 519-524
Author(s):  
Sang An Ha ◽  
Jei Pil Wang
Keyword(s):  
Magnetic Field ◽  
Heavy Metals ◽  
Removal Rate ◽  
Underground Water ◽  
Liquid Electrode ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Removal Of Heavy Metals ◽  
High Removal Rate ◽  
Membrane Treatment

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

scholarly journals Biological Removal NOx from Simulated Flue gas in aerobic biofilter, by Jiang R., Huang S.B. and Yang J.

2013 ◽  
Vol 10 (2) ◽  
pp. 241-248
Keyword(s):  
Gas Phase ◽  
Flue Gas ◽  
Removal Rate ◽  
Nox Removal ◽  
Biological Removal ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
O2 Concentration ◽  
Blank Experiment ◽  
Nitrate And Nitrite

A bench-scale biofiltration system was developed to evaluate the NOx removal efficiency under high oxygen concentration. The system had been running for 120 days and kept on a steady NOx removal rate above 80%. A stable NOx removal with an efficiency of more than 80% from the gas phase can be obtained by the bioreactor concept, when flue gas containing NO (400-600 ppmv) and a certain O2 concentration (0-20%). In the blank experiment, less than 35% NO was removed as oxygen increased. The tendency of the three curves about NO removal rate with various O2 concentrations was mainly similar but some differences in the highest and lowest removal rate happened in the definite O2 concentration range. Oxygen was shown to have a significant effect on NOx removal at the first two or three days when oxygen concentration increased sharply. The higher concentration NO influent gas contained, the longer time the microflora need to regain activities. Compared with humidifier, microbial regenerator which was incorporated in biofilter can improve aerobic denitrifying bacteria activity by applying alternating oxic–anoxic conditions in the presence of nitrate and nitrite. Oxidation-Reduction Potential (ORP) and Dissolved Oxygen (DO) were used to control the dose of carbon source.

The pretreatment of acrylonitrile and styrene with the ozonation process

1997 ◽  
Vol 36 (2-3) ◽  
pp. 263-270 ◽  
Author(s):  
Cheng-Nan Chang ◽  
Jih-Gaw Lin ◽  
Allen C. Chao ◽  
Bo-Chuan Cho ◽  
Ruey-Fang Yu
Keyword(s):  
Organic Nitrogen ◽  
Ph Value ◽  
Raw Materials ◽  
Removal Rate ◽  
Acrylonitrile Butadiene Styrene ◽  
Ozone Treatment ◽  
Oxidation Reduction ◽  
Initial Ph ◽  
Cod Removal Rate ◽  
Ozonation Process

Acrylonitrile and styrene are used as the raw materials for manufacturing acrylic fiber, thus they are often found as pollutants in the petrochemical wastewater. This study utilizes ozone to decompose the organic nitrogen contained in acrylonitrile and styrene, and the oxidation process was monitored using on-line measurements of oxidation-reduction potential (ORP) and pH. The efficiency of organic nitrogen decomposition was also estimated based on the COD, organic nitrogen, TOC, ammonia-N, nitrite, and nitrate measurements. Both the initial pH and alkalinity are observed to affect the degradation rate of organic nitrogen. The acrylonitrile sample with the lowest initial pH value (i.e., 4.0) has a shorter t1/2 of 18.9 min and that for samples of the highest initial pH (i.e., 11) was 34 min. The alkalinity of one acrylonitrile sample was boosted by adding 500 mg/l CaCO3, to simulate the field ABS (Acrylonitrile-Butadiene-Styrene) wastewater effluent. It was observed that within a short ozone contact time, the acrylonitrile sample spiked with 500 mg/l CaCO3 had the highest COD decomposition rate of 0.411 min−1, or 1.3 times more than that for samples without addition of CaCO3. Results of the ozonation process can be fitted with a modified Nernst equation for the various pH conditions. Additionally, the ozone treated synthetic ABS sample shows a faster COD removal rate in the subsequent biological process than those samples without ozone treatment.

Study on SO2, NO Removal from Flue Gas Using an Aqueous NaClO2 Solution with Oxidation Reduction Potential and pH Control

2014 ◽  
Vol 955-959 ◽  
pp. 2221-2225 ◽  
Author(s):  
Ye Sun
Keyword(s):  
Removal Efficiency ◽  
Flue Gas ◽  
Feeding Rate ◽  
Ph Value ◽  
Ph Control ◽  
Sodium Chlorite ◽  
Regression Equations ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Optimized Conditions

Removal of SO2 and NO from the flue gas using an aqueous sodium chlorite solution was achieved in a bubbling reactor, ORP and pH were used as monitoring parameter. The effect of pH, NaClO2 feeding rate and SO2 concentration on simultaneous removal of SO2 and NOx efficiencies were systematical investigated. The results showed that SO2 removal efficiency was always 100% and NOx removal efficiency could achieve 65% at optimized conditions, the optimized pH value of 5-5.5 was observed. The correlation analysis among ORP, original pH, NaClO2 feeding rate and input SO2 concentration was established using multiple regression equations.

scholarly journals Dynamic Experimental Study on Treatment of Acid Mine Drainage by Bacteria Supported in Natural Minerals

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 439 ◽  
Author(s):  
Yanrong Dong ◽  
Junzhen Di ◽  
Xianjun Wang ◽  
Lindan Xue ◽  
Zhenhua Yang ◽  
...  
Keyword(s):  
Acid Mine Drainage ◽  
Treatment Effect ◽  
Mine Drainage ◽  
Ph Value ◽  
Oxygen Demand ◽  
Sulfate Reducing ◽  
Acid Mine ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Geographic Origins

In order to solve the problem of pollution of acid mine drainage (AMD), such as low pH value and being rich in SO42−, Fe and Mn pollution ions, etc., immobilized particles were prepared by using sugar cane-refining waste (bagasse), a natural composite mineral (called medical stone in China) and sulfate-reducing bacteria (SRB) as substrate materials, based on microbial immobilization technology. Medical stone is a kind of composite mineral with absorbability, non-toxicity and biological activity. The adsorption capacity of medical stone is different according to its geographic origins. Two dynamic columns were constructed with Column 1 filled by Fuxin’s medical stone-enhanced SRB immobilized particles, and Column 2 filled by Dengfeng’s medical stone-enhanced SRB immobilized particles as fillers. The treatment effect on AMD with SRB-immobilized particles enhanced by medical stone from different areas was compared. Results showed that Column 2 had better treatment effect on AMD. The average effluent pH value of Column 2 was 6.98, the average oxidation reduction potential (ORP) value was −70.17 mV, the average removal percentages of SO42−, Fe2+ and Mn2+ were 70.13%, 83.82% and 59.43%, respectively, and the average chemical oxygen demand (COD) emission was 555.48 mg/L.

scholarly journals Determination of the Relaxation Time of Physico-Chemical Characteristics of Water After Cavitation Treatment

2001 ◽  
Vol 14 (5) ◽  
pp. 550-563
Author(s):  
Veronika V. Shelenkova ◽  
Keyword(s):  
Electrical Conductivity ◽  
Relaxation Time ◽  
Ph Value ◽  
Hydrodynamic Cavitation ◽  
Time Range ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Physico Chemical ◽  
Cavitation Action

The results of hydrodynamic treatment of water in the supercavitation mode are presented. Changes in the physicochemical properties of water (electrical conductivity, pH, oxidation-reduction potential (ORP), oxygen content (OCP), etc.) were revealed, the rational duration of cavitation treatment of water was established, and data on the relaxation of these properties were obtained. At the same time, there is an increase in temperature, pH and electrical conductivity, a decrease in ORP and CRC. The time range with the most intense changes in pH and ORP is 30–90 s. The rate of pH and ORP change in the range of 30–90 s is three and two times higher, respectively, than in the range of 90–300 s. These results correlate fairly well with the results of studies of the effect of ultrasound on water. It was found that the maximum pH value is reached under cavitation action for 180 s. The minimum value of ORP takes at 300 s of cavitation treatment, but remains in the area of positive values. It is shown that during the relaxation time, activated water after treatment for 200 min under the used modes of hydrodynamic cavitation treatment does not return to its original state in all measured parameters

scholarly journals Effect of liming on the change of some agrochemical soil properties in a long-term fertilization experiment

2014 ◽  
Vol 60 (No. 4) ◽  
pp. 146-150 ◽  
Author(s):  
I. Jaskulska ◽  
D. Jaskulski ◽  
M. Kobierski
Keyword(s):  
Organic Carbon ◽  
Soil Properties ◽  
Soil Ph ◽  
Ph Value ◽  
Manganese Content ◽  
Farmyard Manure ◽  
Available Phosphorus ◽  
Long Term Experiment ◽  
Set Up

For 10 years (1999&ndash;2008) there was investigated the effect of liming on soil pH<sub>KCl</sub> and on organic carbon, available forms of macroelements and DTPA-extracted forms of some metals in 6 different fertilization objects in a long-term experiment set up in 1948: without fertilization (0), straw + NPK (STR NPK), NPK, farmyard manure (FYM), FYM NPK, FYM NPKMgCa. As a result of the application of 12.0 t/ha of lime (4.3 t Ca/ha), an increase was found not only in soil pH value but also in organic carbon, plant available phosphorus, zinc and copper contents and a decrease in manganese content. Despite significant changes in the soil properties, they still varied across the long-term fertilization objects.

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