CODCr Values Research Articles

Changes in Organics and Nitrogen during Ozonation of Anaerobic Digester Effluent

The objective of this study is to investigate the consequence of ozone dosage rate on the qualitative change in organic compounds and nitrogen in anaerobic digester effluent during the ozone process. Therefore, ozonation improves the biodegradability of recalcitrant organic compounds, quickly oxidizes the unsaturated bond, and forms radicals that continue to deteriorate other organic matter. In this study, ozonation was performed in a microbubble column reactor; the use of microbubble ozone improves the status of chemical oxygen demand (COD) and changes of organic nitrogen to inorganic compounds. The ozone injection rates were 1.0, 3.2, and 6.2 mg/L/min. The samples obtained during the ozone treatments were monitored for CODMn, CODCr, TOC, NO2−-N, NO3−-N, NH4+-N, T-N, and Org-N. The ozone dose increased 1.0 to 6.2 mg/L and it increased the degradation ratio 40% and the total organic carbon 20% during 20 min of reaction time. During the ozonation, the CODCr and CODMn values were increased per unit of ozone consumption. The ozone treatment showed organic nitrogen mineralization and degradation of organic compounds with the contribution of the microbubble ozone oxidation process and is a good option for removing non-biodegradable organic compounds. The original application of the microbubble ozone process, with the degradation of organic compounds from a domestic wastewater treatment plant, was investigated.

Temporal and Spatial Distribution and Fluorescence Spectra of Dissolved Organic Matter in Plateau Lakes: A Case Study of Qinghai Lake

Dissolved organic matter (DOM) has a great impact on the main pollution indicators of lakes (such as chemical oxygen demand, COD). Therefore, DOM is the research basis for understanding the meaning of the water environment and the laws of the migration and transformation of pollutants. Qinghai Lake is one of the world’s typical inland plateau lake wetlands. It plays important roles in improving and regulating the climate and in promoting a virtuous regional ecological cycle. In recent years, with the acceleration of urbanization and the rapid development of tourism, under the background of climate change, and with grassland degradation and precipitation change, the whole basin of Qinghai Lake has been facing great ecological pressure. In order to comprehensively explore the water environment of Qinghai Lake and to protect the sustainable development of the basin, a systematic study was carried out on the whole basin of Qinghai Lake. The results show the following: (1) from 2010 to 2020, the annual average value of CODCr in Qinghai Lake fluctuated in the range from class III to class V according to the surface water environmental quality standard, showing first a downward trend and then an upward trend. (2) The concentration of CDOM in Qinghai Lake had obvious temporal and spatial changes. (3) The spatial distribution of the total fluorescence intensity of FDOM in water was also different in different seasons. However, in the three surveys, the area with the highest total fluorescence intensity of FDOM in the water body appeared near Erlangjian in the south of Qinghai Province, indicating that anthropogenic sources are the main controlling factors of dissolved organic matter in the lake.

A triethanolamine-assisted fabrication of stable Sb doped-SnO2/Ti electrode for electrocatalytic oxidation of rhodamine B

A stable Sb doped SnO2/Ti electrode was successfully fabricated via a triethanolamine-assisted method and used as an anode to degrade Rodanmine B under the acid condition in electrocatalytic oxidation process. The surface of the fabricated Sb-SnO2/Ti was covered 200 nm broccoli-like microsphere mainly composed of Sn element and O element. It was found that the Sb-SnO2/Ti electrode was not changed obviously by the comparison of XRD, XPS, FT-IR, Raman spectrum, and DRUV-Vis before and after reaction. The electrochemical oxidation performance was investigated using Rhodamine B (43.8 mg/L) under the acid solution (pH = 2.0). After 30 cycle tests, the Sb-SnO2/Ti electrode has still a high electrocatalytic activity, and the removal rate of color was over 83%. The CV curve discovered there were three unchanged oxidations peaks at −0.675 V, −0.245 V, and 0.475 V, indicating that the degradation path was consistent during the electrochemical reaction. Moreover, high-contained RhB solution (438 mg/L) was degraded at 10.0 V applied voltage, and the removal rate (CODCr) was over 87% after 270 min. The reaction order was a quasi-second-order kinetics based on the CODCr values in the electrocatalysis system. The i-t curve disclosed that the fabricated Sb-SnO2/Ti electrode was very stable. All experimental data identified that the prepared electrode was high-activate and stable reasonably, which could be used as an anode for the elimination of organic pollutant in wastewater.

The correlation analysis of TOC, CODCr and fluorescence characteristics in MPR

Water samples from different biochemical reaction time in one reactor period in Micro-Pressure Inner-Loop Bioreactor (MPR) were measured respectively with adopt Excitation-emission matrix (EEM) fluorescence spectroscopy, Total organic carbon (TOC) and chemical oxygen demand (CODCr),analyzed the correlation among the fluorescence integrates volume, TOC and CODCr.Results showed that with the increase of biochemical treatment time, sewage fluorescence integrates volume declined significantly, known fluorescence integrates volume, CODCr and TOC value better correlation, by fluorescence spectrometry analyzed fluorescence characteristics of sewage to determine the organic wastewater degradation effect, can be simpler and more rapid the judgment of the sewage treatment effect.

Electrochemical Behavior of Manganese Oxide Ores Using Coke Wastewater in Sulfuric Acid Solution

The coke wastewater reductive leaching of pyrolusite ore in sulfuric acid solution was studied. This study was performed in two stages. First, the influence of tractable and refractory pollutants of coke wastewater on manganese leaching was determined. It was shown that the leaching efficiency of manganese is very sensitive to the decomposition of intractable pollutants. With the decrease of 1.85 g/L CODcr value of those contaminants, the extraction ratio of manganese increased more than 16% and exceeded 97.3%. Second, the corrosion behavior of pyrolusite ore in simulative wastewater solution was investigated using cyclic voltammograms, polarization curves, and Mott–Schottky curves. The reduction of manganese oxide ore by recalcitrant organic compounds involves two courses—the inducing conversion of manganese oxide to MnO·OH intermediate with hydrogen and free electron, which is from the oxidation of easily oxidized substances and the oxidation of persistent organic matter by this derivative. As a consequence, the latter process leads to the increment in manganese extraction efficiency. Coke wastewater is a promising reducing agent for MnO2. Likewise, it could be clarified and recycling. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13039, 2019

Analysis on Water Quality Characteristics of Typical Black and Stinking River in Chengdu City by SWMM

In this paper, based on Storm Water Management Model (SWMM) mechanism, referring to the model parameters of domestic and foreign related research achievements, combined with field monitoring data, a non-point source pollution load calculation model is constructed, and the corresponding parameters are calibrated. The pollution load and pollution change process of chemical oxygen demand (CODCr), ammonia nitrogen (NH3-N) and total phosphorus (TP) under different rainfall conditions were analyzed in the investigation area. The model calculated values are in good agreement with the actual measure results. Under different rainfall conditions, the maximum value of pollutants appeared in early and middle rainfall stage, while gradually decreased in latter, with the increase of rainfall, pollution of receiving water becomes greater, and the pollutant concentration shows a downward trend during rainfall process. Measured value of CODCr is higher than the simulated one, both decreased gradually with the rainfall, measured NH3-N concentration in mid-term rainfall increased slightly due to the uninterrupted direct emission of domestic sewage in this area, measured TP concentration in early stage of rainfall declined not obvious, but with the rainfall enhancement, various phosphorus compounds by erosion gradually dissolved finally into the river, partially offset by a dilution effect, as the subsequent rainfall carried over, total phosphorus pollutants continued to decline. While as impervious surface area goes on, both runoff and total pollutants increase.

Boosting and tuning the visible photocatalytic degradation performances towards reactive blue 21 via dyes@MOF composites

A porous copper-based metal-organic framework (Cu-MOF) of 1 was selected and further elaborately tailored by encapsulating visible-light photosensitive Basic Yellow 24 (BY24), Basic Red 14 (BR14) and Methylene Blue (MB) to generate three novel Cu-MOF-based composites BY24@1, BR14@1 and MB@1. Due to naturally inheriting the excellent photoresponsive talents from introduced dye molecules, the visible-light absorption performances of three composites have been markedly improved and their energy band gaps (Eg) were determined to be 2.19, 2.10 and 1.76 eV, respectively. Further investigations demonstrated that three composites could effectively photodegrade Reactive Blue 21 (RB21) under visible light irradiation, with degradation efficiencies increased from 78.8% of 1 to 89.0% for BY24@1, 91.5% for BR14@1 and 97.3% for MB@1. The high-efficiency and diversified performances of dye@1 in destroying RB21 reveal the significant achievements in tailoring the photocatalytic capabilities via introducing dyes with different photosensitivity into identical porous copper-organic framework. This elaborate sensitization strategy may open up more applications of such composites sensitized by high visible photosensitive dyes. In addition, photocatalytic recyclability and optimum pH conditions of MB@1, the CODCr values of original/residual RB21 solution, possible photocatalytic mechanisms including enhancing and tuning mechanisms also were investigated in detail.

A Modified Method for the Accurate Determination of Chemical Oxygen Demand (COD) in High Chloride Oilfield Wastewater

In this work, in order to find a method for the accurate determination of chemical oxygen demand (CODCr) in high chloride oilfield wastewater, the interferences of chloridion (Cl-) on CODCr determination were first studied based on the Chinese national standard GB 11914-89. The results showed that the CODCr values and deviations determined by the classical potassium dichromate (K2Cr2O7) method increased gradually with the increase of Cl- mass concentration in water samples. Then, theoretical and experimental studies on reducing interferences of Cl- on CODCr determination were carried out. The results showed that different concentrations of K2Cr2O7 exhibited different oxidation capacities on Cl-, while having little effects on the oxidation of organic compounds. More specifically, when the concentration of K2Cr2O7 was 0.025 mol·L-1 and the mass ratio of HgSO4:Cl- was 10:1, the interferences of Cl- on CODCr determination were the slightest. Finally, a low concentration oxidant method was proposed for the accurate determination of CODCr in high chloride oilfield wastewaters. The performances of the proposed method were verified by the simulated and actual high chloride oilfield wastewater. The results showed that when Cl- ≤ 20,000 mg·L-1 and COD < 100 mg·L-1, the relative prediction errors of CODCr provided by the proposed method were acceptable, which revealed that the low concentration oxidant method is feasible and reliable for the determination of CODCr in high chloride oilfield wastewater.

Experimental Study on Treatment of Dyeing Wastewater by Activated Carbon Adsorption, Coagulation and Fenton Oxidation

In this paper dyeing waste water was simulated by reactive brilliant blue XBR, activated carbon adsorption process, coagulation process and chemical oxidation process were used to treat dyeing waste water. In activated carbon adsorption process and coagulation process, the water absorbance values were measured. The CODcr value of water was determined in Fenton chemical oxidation process. Then, the decolorization rate and COD removal rate were calculated respectively. The results showed that the optimum conditions of activated carbon adsorption process were as follows: pH=2, the dosage of activated carbon was 1.2g/L, the adsorption reaction time was 60 min, and the average decolorization rate of the three parallel experiments was 85.30%. The optimum conditions of coagulation experiment were as follows: pH=8~9, PAC dosage was 70mg/L, stirring time was 20min, standing time was 45min, the average decolorization rate of the three parallel experiments was 74.48%. The optimum conditions for Fenton oxidation were Fe2+ 0.05g/L, H2O2 (30%) 14mL/L, pH=3, reaction time 40min. The average CODcr removal rate was 69.35% in three parallel experiments. It can be seen that in the three methods the activated carbon adsorption treatment of dyeing wastewater was the best one.

Potassium dichromate method of coal gasification the study of the typical organic compounds in water

The national standard method is adopted in this paper the water - digestion spectrophotometry for determination of the chemical oxygen demand (COD), after ultrasonic processing of coal gasification water for CODCr measurement. Using the control variable method, measured in different solution pH, ultrasonic frequency, ultrasonic power, reaction conditions of different initial solution concentration, the change of coal gasification water CODCr value under the action of ultrasonic, the experimental results shows that appear when measurement is allowed to fluctuate, data, in order to explain the phenomenon we adopt the combination of the high performance liquid chromatography and mass spectrometry before and after ultrasonic coal gasification qualitative analysis on composition of organic matter in water. To raw water sample chromatography - mass spectrometry (GC/MS) analysis, combined with the spectra analysis of each peak stands for material, select coal gasification typical organic substances in water, with the method of single digestion, the equivalent CODCr values measured after digestion. Order to produce, coal gasification water contained high concentration organic wastewater, such as the national standard method is adopted to eliminate the organic material, therefore to measure the CODCr value is lower than actual CODCr value of the emergence of the phenomenon, the experiment of the effect of ultrasound [9-13] is promote the complex organic chain rupture, also explains the actual measurement data fluctuation phenomenon in the experiment.

Hygienization of Surplus Activated Sludge By Dry Ice

Abstract The presence of pathogenic microorganisms in sewage sludge is one of the crucial factors affecting their use in agriculture and in nature. An appropriate method of sludge hygienization can contribute to the reduction of the presence of pathogenic microbes in the sludge or to their complete elimination. This study presents the possibility of using dry ice in the hygienization of surplus activated sludge. The scope of survey covered microbiological as well as physiochemical analyses of the sludge. The microbiological analyses conducted show the hygienization effect of dry ice on surplus activated sludge such as the reduction of the total number of bacteria as well as of pathogenic bacteria. In the case of sludge to dry ice 1:1 voluminal ratio, the total number of bacteria has been reduced by 76%, the number of Salmonella sp. rods by 90%, and Clostridium perfringens by 85%. The results of physiochemical analyses confirmed the destructive effect that dry ice has over microorganisms. The disintegration of microbes by means of dry ice contributed to the increase of supernatant liquid turbidity and to the release of organic matter. For the sludge to dry ice 1:1 voluminal ratio, an increase in turbidity of supernatant liquid by 320 mg SiO2 dm-3 has been proven, as well as an increase in the value of CODCr by 549 mg O2 dm-3, which indicates the release of organic matter into the liquid phase.

EVALUATION OF LANDFILL LEACHATE POLLUTION: FINDINGS FROM A MONITORING STUDY AT MUNICIPAL WASTE LANDFILL

The monitoring that was carried out at the landfill specialized in leachate, groundwater and surface water. There were 6 sampling sites. The observed parameters were pH, BOD5, CODCr, conductivity. Leachate reached the high values in all observed parameters. Groundwater samples were collected at two monitoring wells and the sampling site (A, B, C). Surface water was collected from two sampling sites (D, E). The pH showed slightly acid values at all sampling points. The pH of surface water was slightly acid to neutral. Both BOD5 and CODCr values remained stable over the reporting period. The average conductivity value at sampling points D, E remained constant. In line with the Czech National Standard CSN 75 7221 “Classification of Surface Water Quality” sampling point D belongs to II Water Quality Class – slightly polluted water and sampling site E to Class I water quality – unpolluted water. The authors believe that the fluctuations occurring with regard to the values of certain samples were not caused by the operation of the landfill itself, but were a result of the intense agricultural activity nearby the landfill.

Analysis of Water Quality and Control Countermeasures of Yazidang Reservoir in Ningxia, China

Yazidang Reservoir is a pumped-storage reservoir for water supply in Ningdong Chemical Industry Base of Ningxia, China. It plays an important role as a source of drinking and industrial water supply. Analysis of the water quality from March 2013 to May 2014, the results show that: For organic descriptors, value of CODCr, CODMn and DO can satisfy with class III, but some values of BOD5 exceed the standard limitation. For index of nutrients, some values of TP exceed the standard, and TN greatly exceed the standard limitation. Using potential eutrophication to evaluate the reservoir water quality, the results show that Yazidang Reservoir is on a very high level of nitrogen and phosphorus nutrition, reach to level of eutrophy-extremely eutrophy. Considering the current situation of water quality in Yazidang Reservoir, some countermeasures should be carried out for pollution prevention and control of water quality, such as strengthening management, enhancing water quality monitoring and water quality evaluation, simulation, eutrophication control and estimation environmental capacity of reservoir.

Effects on Coagulation to Biogas-Slurry from Cattle Dung

To explore purification approach of anaerobic-digested-slurry from cattle dung, this study translated a technology in inorganic coagulation. Under the same condition, a coagulation experiment was carried out by three kinds inorganic coagulants such as polyaluminium chloride (PAC), aluminum sulfate and ferric chloride, respectively, then measured indicators of pH value, BOD5 value, CODcr value, ammonia nitrogen value, turbidity value. Results showed that there was a varying degree of purification effect, and the removal rate of the above indicators increased as the coagulant dosage increasing, the ferric chloride with the dosage of 960mg/L was the best one in purifying effect among the three coagulants. It is feasible that coagulation technology was used to pretreatment biogas slurry from cattle dung, and most of the indicators reached Chinese national standard basically (GB 18596-2001).

Microbial community dynamics in hybrid biological reactor treating petrochemical wastewater

Hybrid biological reactor (HBR) was developed by adding carriers to the aeration tanks, and could be applied to improve the poor nitrification ability of overloaded petrochemical wastewater treatment plants. Using the normal activated sludge process (ASP) as a control, the performance of ASP combined with HBR for the treatment of petrochemical wastewater was studied. When the influent load was 0.97 kg CODCr/m3 d (CODCr, Chemical Oxygen Demand with the oxidant of K2Cr2O4), effluent of ASP contained 138.2 mg/L CODCr and 8.2 mg/L NH4+-N, and the CODCr and NH4+-N concentration in effluent of HBR was 120.8 and 1.6 mg/L, respectively, indicating that both processes had good removal capacities for petrochemical wastewater. When the load was increased to 1.94 kg CODCr/m3 d, there was no apparent change in effluent CODCr values of HBR and ASP. However, a great difference in the removal efficiency of NH4+-N between HBR and ASP was observed. NH4+-N concentration in effluents of ASP and HBR was 16 and 1.7 mg/L, respectively, suggesting that HBR had a much better treatment capacity for NH4+-N than ASP. Using ribosomal intergenic spacer analysis fingerprinting and 16S rDNA sequence analysis, a big difference in microbial community structure was found between the two processes. And there existed simultaneous nitrification and denitrification in HBR system. Compared with ASP, HBR had more advantages, such as high utilization of oxygen, less sludge generation, and lower power consumption.

Pollution of the Ecosystem of the Rusalka City Lake with Heavy Metals / Zanieczyszczenie Ekosystemu Śródmiejskiego Jeziora Rusałka Metalami Ciężkimi

Abstract In the vegetation season April-October 2010, the value of and the changes in Zntot., Cutot., Cdtot. and Pbtot. concentrations in the water of the Rusalka flow-through lake (with average water retention of ca 30 days) situated in the city centre of Szczecin were determined. Water temperature, pH, concentration of dissolved oxygen (with calculation of water saturation with O2), COD-Cr and BOD5, total hardness, - 3 HCO concentration (as total alkalinity), Cl-, - 24 SO , Mntot and Fetot were also determined. The data collected may be used to evaluate the ecological and chemical status of the surface waters under investigation. As far as the ecological status of the Rusalka Lake is concerned, the investigated waters were found, based on the official criteria being in force in Poland in evaluation of the ecological and chemical status of surface waters, to conform to water quality classes I and II considering total zinc and copper concentrations, temperature and dissolved oxygen concentration (except water inflow to the lake in August) as well as BOD5, - 24 SO and Cl- concentrations and pH value; however, they were always worse than water quality class II while taking the COD-Cr values into account. Regarding the chemical status of the investigated waters, total cadmium and lead concentrations were the levels exceeding the admissible values according to the official criteria in Poland. Changes in the values of indices being investigated along water flow path allowed stating that the equilibriums between the sedimentation and the resuspension and the dissolution processes during the research period were shifted towards sedimentation in case of Zn and Cd only, as well as of the organic matter sedimenting in the form of divalent cation- and divalent anion-sorbing gels. Although three phytoplankton blooms occurred in the body of water, unfortunately weak ones, the dissimilation processes prevailed over assimilation.

Bacteriological and Physicochemical Water Quality of Four Ponds of Dhaka Metropolis

The aerobic heterotrophic bacterial count of four pond water samples ranged between 6.92×104 and 1.72×106cfu/100 ml. The highest count (1.72×106 cfu/100 ml) was recorded in Zahurul Haq Hall pond water.Enteric bacterial count was found in between 1.69×104 and 3.31×105 cfu/100ml in water samples. A total of 79 isolates were obtained of which 24 were randomly selected for further study. Among them Bacillus, Micrococcus and Planococcus were Gram-positive, while Escherichia, Enterobacter and Klebsiella were Gram-negative. Physicochemical parameters of the ponds satisfied water quality standards except NH4+-N. Among the ponds, CODCr and BOD5 values of the water samples were 18.29-19.75 mg/l and 3.18-6.05 mg/l, respectively. Most of the Gram negative bacteria were found to be multi drug resistant. DOI: http://dx.doi.org/10.3329/bjb.v41i1.11083 Bangladesh J. Bot. 41(1): 55-60, 2012 (June)

The removal of COD from coking wastewater using extraction replacement–biodegradation coupling

Using the extraction replacement–biodegradation coupling technique, the removal of chemical oxygen demand (CODcr) from coking wastewater was successfully carried out, and the appropriate extractant type, extractant/diluter ratio, extraction time, and the extractant/wastewater phase ratio were also determined. The results show that when n-octanol and cyclohexane, in a ratio of 1:1, were selected as the mixed extractant, nitrogen-containing heterocyclic compounds (NHCs), such as pyridines and quinolines, were effectively extracted and replaced by the extractant from coking wastewater. As a result, the biodegradable nature of coking wastewater could be improved significantly. After pretreating coking wastewater with the extraction replacement method for 5min using a 1:1 ratio of extractant to wastewater and following with biodegradation treatment, the biochemical oxygen demand for five days (BOD5)/CODcr values and the CODcr removal efficiencies of the coking wastewater effluent were improved from 0.06 to 0.29 and from 68.81% to 88.63%, respectively. The result of economic feasibility analysis shows that, by controlling the treaded quantity and concentration of coking wastewater, the extraction replacement–biodegradation coupling process can become a profitable project.

Pilot Scale Study on Biological Nutrient Removal and Membrane Fouling Alleviation in Combined Membrane Bioreactor for Municipal Wastewater Treatment

To solve the problem of eutrophication in receiving water, a novel Membrane Bioreactor (MBR) with combined configuration was designed for municipal wastewater treatment and reclamation. By dividing bioreactor into three zones, the combined MBR operated under anoxic, anaerobic and aerobic conditions. It provided optimum conditions for nitrification, denitrifying and phosphate accumulating bacterial growth which resulted in high biological nutrient removal rate directly. The operational performance of combined MBR pilot plant showed that it exhibited high nutrient removal rate on Chemical oxygen demand (CODcr), total nitrogen (TN) and total phosphorus (TP). The mean value of effluent CODcr, TN and TP removal rate was 90.63%, 63.05% and 60.51% respectively during 180 days of operation. In order to obtain stable membrane flux, the combined MBR packed with fibrous bio-film carrier and added diatomite. Furthermore, it could alleviate membrane fouling effectively. As a result, the combined MBR improved effluent water quality significantly and alleviated membrane fouling remarkably.

Study on Laccase Immobilization with PVA Materials

This article used glutaraldehyde to immobilize laccase and then used the immobilization laccase to treatment papermaking effluent. The study first discussed the effect of PVA crosslinking degree, epoxidation temperature and epoxidation time for the performance of PVA carrier. The research found 100g PVA ( mass fraction is 10%), 35mL glutaraldehyde, 10mL DMSO and 10mL epoxy chloropropane reacted 6h in 60 °C, pH=11-12 and surface amount of epoxidation reached the max value. its amount is 0.3073mmol . And then the laccase were fixed with the max value. The optimum conditions of immobilization laccase treated papermaking effluent were researched. The effects of treated time, temperature, pH value, the dosage of enzyme and HBT, the removal value of CODCr and decolorization were tested. The effects of treated time, temperature, pH value, the dosage of enzyme and HBT, concentration of Cu2+ on the removal value of CODCr and decolorization were tested. It was found that the optimum conditions for immobilization laccase treatment were Cu2+ 0.006μmol/L, HBT 0.008g/L, pH=4, temperature 50°C, reation time 6h (with air injected). The result showed that the CODCr removal rate reached 63.15%, the decolorization rate reached 61.53% in 8h. Furthermore BOD/COD of chemical pulp effluent was increased from 0.17 to 0.455. Comparing with dissociation laccase, stabilities of immobilization laccase for hot and pH increased. Through this research a new advanced treatment method can be found. This method can improve biodegradation performance of papermaking effluent. Papermaking effluent treated by aerobic, anaerobic and laccase system will achieve standard discharge.