scholarly journals Plasma electrolysis method for reducing COD in tofu wastewater

2018 ◽  
Vol 67 ◽  
pp. 01002 ◽  
Author(s):  
Widya Pangestika ◽  
Nadira Kamilia Permatasari ◽  
Nelson Saksono
Keyword(s):  
Chemical Oxygen Demand ◽  
Oxygen Demand ◽  
Potential Method ◽  
High Concentration ◽  
Radical Species ◽  
Plasma Electrolysis ◽  
Electrolysis Method ◽  
Organic Wastewater

Chemical Oxygen Demand (COD) is one of pollution parameter that have to be reduced so the wastewater may not harm the environment. Tofu wastewater is one of the organic wastewater that have high concentration of COD. The level of COD in untreated tofu wastewater outnumbered 8000 mg/L. This parameter could be lowered by plasma electrolysis that produced radical species to degrade pollutants in the wastewater. Three variations had been done in this study, such as: the addition of Fe2+ ion as a catalyst, the voltage, and the depth of anode. It was shown that addition of 60 mg/L of Fe2+ ion in plasma electrolysis could degrade COD in tofu wastewater to 73%. The effect of the voltage also had been studied. By using the voltage at 750 V could discard COD as much as 85%. The last variation that was conducted in this study is the effect of the depth of anode in plasma electrolysis. The result showed that 73% of COD in tofu wastewater could be reduced by using the depth of anode 2 cm. All of these results showed that plasma electrolysis is a potential method to degrade pollution parameter, especially COD in tofu wastewater.

scholarly journals Analysis of Wastewater Generated in Greenhouse Soilless Tomato Cultivation in Central Europe

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2538 ◽  
Author(s):  
Artur Mielcarek ◽  
Joanna Rodziewicz ◽  
Wojciech Janczukowicz ◽  
Artur Dobrowolski
Keyword(s):  
Organic Matter ◽  
Chemical Oxygen Demand ◽  
Central Europe ◽  
Oxygen Demand ◽  
Complete Recovery ◽  
Qualitative Composition ◽  
Coconut Fiber ◽  
High Concentration ◽  
North Eastern ◽  
Soilless Cultivation

Soilless plantations under cover constitute a significant part of horticulture. This study aimed at determining the qualitative composition of wastewater generated from the soilless cultivation of tomato under cover. This is important for managing the wastewater, which may be recirculated to allow the or employ a partial or complete recovery of minerals. Two plantations located in north-eastern Poland, which differed in the type of substratum (coconut fiber or rockwool), were studied. The generated wastewater was characterized by a low content of organic matter and a high concentration of total nitrogen (TN), total phosphorus (TP), and salinity (EC). Over 99% of the TN was constituted by nitrates. The chemical oxygen demand (COD) changed from 50.07 to 75.82 mgO2·L−1 (greenhouse 1), and from 37.35 to 78.12 mgO2·L−1 (greenhouse 2); the content of TN changed from 403.59 to 614.89 mgN·L−1 (greenhouse 1), and from 270.00 to 577.40 mgN·L−1 (greenhouse 2); that of TP changed from 35.44 to 78.00 mgP·L−1 (greenhouse 1), and from 54.10 to 104.00 mgP·L−1 (greenhouse 2); and the EC changed from 3.53 to 6.93 mS·cm−1 (greenhouse 1), and from 4.94 to 6.94 mS·cm−1 (greenhouse 2). No statistically significant correlations were noted between TN and TP, or between TP and EC.

Coupling of anodic oxidation and adsorption by granular activated carbon for chemical oxygen demand removal from 4,4′-diaminostilbene-2,2′-disulfonic acid wastewater

2010 ◽  
Vol 62 (11) ◽  
pp. 2669-2677 ◽  
Author(s):  
Lizhang Wang ◽  
Yuemin Zhao
Keyword(s):  
Activated Carbon ◽  
Chemical Oxygen Demand ◽  
Residence Time ◽  
Applied Voltage ◽  
Oxygen Demand ◽  
Granular Activated Carbon ◽  
Cod Removal ◽  
Disulfonic Acid ◽  
High Concentration ◽  
Solution Ph

Experiments were performed to reduce chemical oxygen demand (COD) from 4,4′-diaminostilbene-2,2′-disulfonic (DSD) acid manufacturing wastewater using electrochemical oxidation coupled with adsorption by granular activated carbon. The COD removal is affected by the residence time and applied voltage. When the residence time is increased, lower value of COD effluent could be obtained, however, the average current efficiency (ACE) decreased rapidly, and so does the applied voltage. In addition, aeration could effectively enhance COD removal efficiency and protect anodes from corrosion. Furthermore, the acidic condition is beneficial to the rapid decrease of COD and the values of pH effluent are independent of the initial solution pH. The optimization conditions obtained from these experiments are applied voltage of 4.8 V, residence time of 180 min and air–liquid ratio of 4.2 with the COD effluent of about 690 mg L−1. In these cases, the ACE and energy consumption are 388% and 4.144 kW h kg−1 COD, respectively. These perfect results from the experiments illustrate that the combined process is a considerable alternative for the treatment of industrial wastewater containing high concentration of organic pollutants and salinity.

Removal of Organic Matters in Pesticide Wastewater by Supercritical Water Oxidation

2014 ◽  
Vol 955-959 ◽  
pp. 2340-2348 ◽  
Author(s):  
Dong Hai Xu ◽  
Shu Zhong Wang ◽  
Chuan Bao Huang ◽  
Xing Ying Tang ◽  
Yang Guo ◽  
...  
Keyword(s):  
Chemical Oxygen Demand ◽  
Residence Time ◽  
Supercritical Water ◽  
Water Oxidation ◽  
Oxygen Demand ◽  
Reaction Pathways ◽  
Experimental Plant ◽  
Supercritical Water Oxidation ◽  
High Concentration ◽  
Organic Matters

Supercritical water oxidation (SCWO) is an alternative to effectively dispose many varieties of organic wastewaters. In this article, a high concentration pesticide wastewater with very complicated components was handled by SCWO in a batch experimental plant at 25 MPa, 410–580 °C within the oxidant coefficient of 1.1–4.0 and the residence time of 1.0–10.0 min. The results show that reaction temperature, oxidant coefficient, residence time can improve XCOD(removal efficiency of chemical oxygen demand) of reactor effluent. XCODreaches up to 99.89% at 550 °C, 25 MPa with the oxidant coefficient of 3.0 and the residence time of 5.0 min, and the corresponding COD concentration is 73 mg/L. Residence time indicates a relatively more important influence on COD1at higher reaction temperatures and OCs. Furthermore, possible reaction pathways for SCWO of organic matters in the pesticide wastewater were also proposed primarily.

Degradation of high-concentration simulated organic wastewater by DBD plasma

2019 ◽  
Vol 80 (8) ◽  
pp. 1413-1420
Author(s):  
Xing-Quan Wang ◽  
Xing Li ◽  
Ren-Wu Zhou ◽  
Jun Huang ◽  
Wei Chen ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Methyl Violet ◽  
Oxygen Demand ◽  
Air Plasma ◽  
High Concentration ◽  
Dbd Plasma ◽  
Lower Efficiency ◽  
Vis Spectroscopy ◽  
Decoloration Rate ◽  
Organic Wastewater

Abstract In this study, a high-concentration simulated organic wastewater, made by dissolving methyl violet in water, was degraded using dielectric barrier discharge (DBD) plasma generated in air and O2 respectively. The decoloration rate and chemical oxygen demand (COD) of wastewater were evaluated during plasma treatments with the initial concentration of methyl violet of 300 mg L−1. Results showed that the highest decoloration rate of around 100% within 10 min and the highest COD decrease of 33% within 60 min could be achieved with the O2 plasma treatment at the discharge voltage of 10 kV, while air plasma treatment showed lower efficiency in decolorizing the methyl violet solution and lower COD decrease (24%) after 60 min treatment. UV-Vis spectroscopy and chemical analysis of generated by-products during the plasma-enabled degradation process revealed that the methyl violet molecules could be completely decomposed into some refractory organics in the solution. Based on the experimental results and literature review, a pathway of methyl violet degradation attributed to energetic electrons and highly reactive species generated by DBD was proposed.

REMOVAL OF DYE AND CHEMICAL OXYGEN DEMAND (COD) REDUCTION FROM TEXTILE INDUSTRIAL WASTEWATER USING HYBRID BIOREACTORS

2014 ◽  
Vol 13 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Ghasem Najafpour Darzi ◽  
Reza Katal ◽  
Hossein Zare ◽  
Seyed Omid Rastegar ◽  
Poorya Mavaddat
Keyword(s):  
Chemical Oxygen Demand ◽  
Industrial Wastewater ◽  
Oxygen Demand ◽  
Cod Reduction

Spatio-temporal Variations in Water Quality Parameter Trends in River Waters

2018 ◽  
Vol 69 (10) ◽  
pp. 2940-2952 ◽  
Author(s):  
Martina Zelenakova ◽  
Pavol Purcz ◽  
Radu Daniel Pintilii ◽  
Peter Blistan ◽  
Petr Hlustik ◽  
...  
Keyword(s):  
Water Quality ◽  
Chemical Oxygen Demand ◽  
Quality Indicators ◽  
Water Resource Management ◽  
Oxygen Demand ◽  
Temporal Variations ◽  
Water Quality Parameter ◽  
Agricultural Activity ◽  
Water Quality Indicators ◽  
Nitrite Nitrogen

Evaluating trends in water quality indicators is a crucial issue in integrated water resource management in any country. In this study eight chemical and physical water quality indicators were analysed in seven river profiles in the River Laborec in eastern Slovakia. The analysed water quality parameters were biochemical oxygen demand (BOD5), chemical oxygen demand (CODCr), pH, temperature (t), ammonium nitrogen (NH4+-N), nitrite nitrogen (NO2--N), nitrate nitrogen (NO3--N), and total phosphorus (TP). Data from the monitored indicators were provided by the Ko�ice branch of the Slovakian Water Management Company, over a period of 15 years from 1999 to 2013. Mann�Kendall non-parametric statistical test was used for the trend analysis. Biochemical and chemical oxygen demand, ammonium and nitrite nitrogen content exhibit decreasing trends in the River Laborec. Decreasing agricultural activity in the area has had a significant impact on the trends in these parameters. However, NO2--N was the significant parameter of water quality because it mostly exceeds the limit value set in Slovak legislation, Regulation No. 269/2010 Coll. In addition, water temperature revealed an increasing trend which could be caused by global increase in air temperature. These results indicate that human activity significantly impacts the water quality.

Treatment of a complex landfill leachate with peat

1978 ◽  
Vol 5 (1) ◽  
pp. 83-97 ◽  
Author(s):  
Robert D. Cameron
Keyword(s):  
Chemical Oxygen Demand ◽  
Ferric Chloride ◽  
Landfill Leachate ◽  
Metal Removal ◽  
Oxygen Demand ◽  
Treatment Method ◽  
Manganese Concentration ◽  
Chemical Pretreatment ◽  
Iron Manganese

The use of cheap, locally available peat as a treatment method for landfill leachate was investigated by passing leachate through plexiglass columns filled with an amorphous-granular peat. Preliminary adjustment of pH showed that reducing pH to 4.8 dramatically reduced adsorption. Increasing the pH to 8.4, metal removal was increased owing to filtration of precipitated metals. The best adsorption of metals occurred at the 'natural' pH of 7.1. Manganese was found to be the limiting pollutant. At the 0.05 mg/ℓ maximum acceptable manganese concentration 94% of the total metals were removed, requiring 159 kg of peat per 1000 ℓ of leachate.Resting the peat for 1 month did significantly increase removal capacity.Desorption of some contaminants occurred when water was percolated through the peat. The desorption test effluent was not toxic to fish although iron, lead and COD (chemical oxygen demand) exceeded acceptable values.Chemical pretreatment using lime and ferric chloride achieved significant iron, manganese and calcium removals. Chemical pretreatment followed by peat adsorption offered no advantage other than reducing toxicity to fish.Peat treatment alone was effective in reducing concentrations to a level that was non-toxic to fish.

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