Removal Efficiency Of CODMn Research Articles

Biofilm growth characteristic and footprint identification in gravity-driven ceramic membrane bioreactor with electro-coagulation under extreme conditions for roofing rainwater purification

The identification of biofilm growth footprints influencing on the biofilm detachment and breakup can advance research into how biofilms form. Thus, a gravity-driven ceramic membrane bioreactor (GDCMBR) was used to investigate the growth, detachment and breakup of biofilm using rainwater pretreated by electrocoagulation under 70-days continuous operation. The in-situ ultrasonic time-domain reflectometry (UTDR) technique was applied to non-invasively determine the biofilm thickness. Initially, the biofilm was slowly thickening, but it would collapse and became thinner after accumulating to a certain level, and then it thickened again in a later period, following a cyclic pattern of ‘thickening - collapsing – thickening’. This is because the biofilm growth is related with the accumulation of flocs, however, excessive floc formation results in the biofilm being overweight till reaching the thickness limit and thus collapsing. Subsequently, the biofilm gradually thickens again due to the floc production and continuous deposition. Although the biofilm was dynamically changing, the water quality of treatment of the biofilm always remained stable. Ammonia nitrogen and total phosphorus have been almost completely removed, while CODMn removal efficiency was around 25%. And total bacteria amount in the membrane concentrate was obviously higher than that in the influent with the greater microbial activity, demonstrating the remarkable enrichment effect on bacteria. The understanding of biofilm growth characteristic and footprint identification enables us to develop rational approaches to control biofilm structure for efficient GDCMBR performance and operation lifespan.

Influence of Temperature on the Removal Efficiency of Organic Matter and Ammonia from Micro-Polluted Source Water

Temperature is an important factor influencing the treatment effect of biological aerated filters (BAFs). In this study, BAFs incorporating biological manganese oxides (BMOs) were used to treat micro-polluted source water containing organic masses and ammonia, and the influence of temperature on the removal efficiency of the pollutants was investigated. The results showed that after the formation of biogenic manganese oxides (BMOs) in the filter layer, the removal efficiency of CODMn significantly improved. When the water temperature was approximately 24 °C, 16 °C, and 6~8 °C, the removal rates of CODMn, ammonia, and manganese were 60.64, 42.55, and 20.48; 98.40, 95.58, and 85.04; and 98.70, 97.63, and 96.38%, respectively. The influence of water temperature on the removal efficiency of the pollutants was hierarchically structured as follows: CODMn > ammonia > manganese. Analysis of the removal efficiencies of the pollutants along the filter layer showed that CODMn had been eliminated in every filtration layer, and ammonia and manganese were mainly removed in the 0~0.4 m and 0~0.8 m regions of the filter layer, respectively. With a decreasing water temperature, the concentrations of CODMn, ammonia, and manganese along the filter layer increased. The biological CODMn, manganese, and ammonia removal processes were all first-order kinetic reactions. With a decreasing water temperature, the kinetic constant k gradually decreased, and the reaction half-life (t1/2) gradually increased.

Aerobic Denitrification Enhanced by Immobilized Slow-Released Iron/Activated Carbon Aquagel Treatment of Low C/N Micropolluted Water: Denitrification Performance, Denitrifying Bacterial Community Co-occurrence, and Implications.

The key limiting factors in the treatment of low C/N micropolluted water bodies are deficient essential electron donors for nitrogen removal processes. An iron/activated carbon aquagel (IACA) was synthesized as a slowly released inorganic electron donor to enhance aerobic denitrification performance in low C/N micropolluted water treatment. The denitrification efficiency in IACA reactors was enhanced by more than 56.72% and the highest of 94.12% was accomplished compared with those of the control reactors. Moreover, the CODMn removal efficiency improved by more than 34.32% in IACA reactors. The Illumina MiSeq sequencing consequence explained that the denitrifying bacteria with facultative denitrification, iron oxidation, and iron reduction function were located in the dominant species niches in the IACA reactors (e.g., Pseudomonas, Leptothrix, and Comamonas). The diversity and richness of the denitrifying bacterial communities were enhanced in the IACA reactors. Network analysis indicated that aerobic denitrifying bacterial consortia in IACA reactors presented a more complicated co-occurrence structure. The IACA reactors presented the potential for long-term denitrification operation. This study affords a pathway to utilize IACA, promoting aerobic denitrification during low C/N micropolluted water body treatment.

Simultaneous Removal of CODMn and Ammonium from Water by Potassium Ferrate-Enhanced Iron-Manganese Co-Oxide Film

Iron-manganese co-oxide film (MeOx) has a high removal efficiency for ammonium (NH4+) and manganese (Mn2+) in our previous studies, but it cannot effectively remove CODMn from water. In this study, the catalytic oxidation ability of MeOx was enhanced by dosage with potassium ferrate (K2FeO4) to achieve the simultaneous removal of CODMn and NH4+ from water in a pilot-scale experimental system. By adding 1.0 mg/L K2FeO4 to enhance the activity of MeOx, the removal efficiencies of CODMn (20.0 mg/L) and NH4+ (1.1 mg/L) were 92.5 ± 1.5% and 60.9 ± 1.4%, respectively, and the pollutants were consistently and efficiently removed for more than 90 days. The effects of the filtration rate, temperature and pH on the removal of CODMn were also explored, and excessive filtration rate (over 11 m/h), lower temperature (below 9.2 °C) and pH (below 6.20) caused a significant decrease in the removal efficiency of CODMn. The removal of CODMn was analyzed at different temperatures, which proved that the kinetics of CODMn oxidation was pseudo-first order. The mature sands (MeOx) from column IV were taken at different times for microscopic characterization. Scanning electron microscope (SEM) showed that some substances were formed on the surface of MeOx and the ratio of C and O elements increased significantly, and the ratio of Mn and Fe elements decreased significantly on the surface of MeOx by electron energy dispersive spectrometer (EDS). However, the elemental composition of MeOx would gradually recover to the initial state after the dosage of Mn2+. According to X-ray photoelectron spectroscopy (XPS) analysis, the substance attached to the surface of MeOx was [(-(CH2)4O-)n], which fell off the surface of MeOx after adding Mn2+. Finally, the mechanism of K2FeO4-enhanced MeOx for CODMn removal was proposed by the analysis of the oxidation process.

Removing Nutrients from Crab-Breeding Wastewater by a Floating Plant–Effective Microorganism Bed

Effective microorganism treatment, a low-cost and remediation measure that with no secondary pollution, was conducted in aquaculture wastewater. Unfortunately, effective microorganism erosion caused by the momentum of water flow under in situ conditions limits the treatment effect. In the channel test, a floating plant bed coupled with the effective microorganism was used to treat crab-breeding wastewater. This study explored the effect of plant coverage and hydraulic loading on aquaculture wastewater purification in the floating plant bed–effective microorganism coupled system. The results show that the effect of the coupled treatment effect is much better than pure microorganism treatment. The pollutant degradation coefficient has a significantly positive correlation with the length of the floating plant bed. A plant coverage rate of 30% and effluent hydraulic loading of 1.0 m3/m2·day are optimum floating plant bed–effective microorganism test conditions. Once the coverage rate exceeded 30%, the increase in the CODMn removal efficiency was not clear. At the same time, the high plant coverage inhibited the oxygen capacity in the water body, which directly led to a decrease in the degradation ability of organic matter by the plant. The biology–ecology coupled technology proposed in this study overcame the shortcomings of the easy-to-lose effective microorganism during the traditional unfixed process and improved the stability of the processing system. It strengthened the crab-breeding wastewater remediation effect. For an in situ application, the artificial restoration system 1 km in length was efficient, and the discharge met the standard at the end of the river.

Influence of temperature on CODMn and Mn2+ removal and microbial community structure in pilot-scale biofilter

Test water temperature (TWT) is a significant operational parameter in biofilter. In this study, a pilot-scale biofilter was established to investigate the removal efficiency of CODMn and Mn2+ and the microbial community structure at different TWT. When CODMn and Mn2+ in the influent were 6–8 and 0.9–1.2 mg/L, respectively, the removal rates were 22.61% and 94.28% at the low TWT, while 69.42% and 97.85% at the high TWT, respectively. Biological CODMn and Mn2+ removal followed the first-order reaction, and at the low and high TWT, the k value was 0.00704 and 0.0738 and 0.0313 and 0.113 min−1, respectively. Organic matter oxidizing bacteria (OMOB, Sphingopyxis, Sphingomonas, Amphiplicatus, Novosphingobium, Gemmatimonas, Chryseolinea and Sphingobium) and manganese oxidizing bacteria (MnOB, Hyphomicrobium, Pedomicrobium and Pseudomonas) were coexisted in 0–1.5 m of the biofilter bed at the low and high TWT, and the abundances were not the main factor affecting the removal efficiency, however the activity.

不同臭氧预处理工艺组合常规工艺对西氿水中COD<sub>Mn</sub>和UV<sub>254</sub>的去除效果

常规工艺对西氿水中的CODMn和UV254处理效果不佳。并且，由于原水中较高的本底值，出水中的CODMn和UV254已无法满足日趋严格的国家标准。因此考虑采用臭氧相关预处理工艺以保障出水水质。研究发现，采用常规工艺时，CODMn和UV254的去除率分别为29.96%~33.73%和24.11%~37.89%；采用预臭氧(O3)–常规工艺时，预臭氧投加量为2.17 mg/L时，CODMn去除率在30.93%~38.11%，UV254去除率在32.04%~45.63%；采用O3/H2O2–常规工艺时，CODMn和UV254的去除率分别为48.78%~49.69% 和41.52%~49.38%；采用O3/UV预处理工艺时，与相同臭氧投加量的单一臭氧预处理单元相比，对CODMn和UV254的去除率分别提高了4.74%~26.29%和7.34%~22.94%。 The CODMn and UV254 in Xijiu Lake could be slightly removed by conventional process. Moreover, the CODMn and UV254 in effluent can’t satisfy the standard for drinking water quality of GB5749-2006 due to the high background level in raw water. Thus, it is to be considered to add with pretreatment process involved ozone to ensure water quality. It was founded by research that the removal efficiency of CODMn and UV254 was 29.96% - 33.73% and 24.11% - 37.89% respectively when conventional process was adopted, the quality of effluent can’t reach the standard stably. The removal efficiency of CODMn and UV254 was 30.93% - 38.11% and 32.04% - 45.63% respectively when combination of ozone and conventional process was adopted (the amount ozone was 2.17 mg/L). It was partly better than conventional process but still can’t reach the standard stably. The removal efficiency of CODMn and UV254 was 48.78% - 49.69% and 41.52% - 49.38% when combination of ozone/hydrogen peroxide and conventional process was adopted, the quality of effluent was better than first two process and more stable. Comparing with single ozone pre-treatment unit in same ozone amount, the removal efficiency of CODMn and UV254 was improved by 4.74% - 26.29% and 7.34% - 22.94%.

Optimization of Electrocoagulation Process to Eliminate CODMn in Micro-Polluted Surface Water Using Response Surface Method

To treat micro-polluted surface water with a better electrocoagulation (EC) process, a response surface method (RSM) was employed to optimize the process parameters. First, the main factor that affected the CODMn removal efficiency in the EC process was determined in single-factor experiments. Then, a quadratic regression model was generated using a RSM. The refined EC operating conditions were a current density of 1.57 mA · cm−2, an initial pH of 7.5, and an operation time of 32 minutes, which maximized the CODMn removal efficiency at 60.56%. Finally, the results of a verification test results corresponded with the calculated values, which indicated that the regression model was accurate and reliable.

Comparison of Fe–Mn enhanced coagulation and O3-BAC for removing natural organic matter from source waters: a case study

This plant-scale investigation compared two process improvement strategies for Lianyungang drinking water treatment plant (L-DWTP), a typical plant employing conventional processes to treat source water impacted by seasonal non-point pollution. Hierarchical cluster analysis grouped it into two clusters, i.e. normal period and polluted period. Originally, the L-DWTP exhibited poor organic matter removal efficiency, and 76.7% of the effluent permanganate index (CODMn) levels exceeded the state regulation requirement (<3 mg/L). In addition, chloroform concentration was observed to exceed the regulation requirement (60 μg/L) by 14.2 and 56.2% in normal and polluted periods. The combined use of FeCl3 and KMnO4 (Fe–Mn enhanced coagulation) increased the CODMn removal efficiency by 10.6%, and decreased the chloroform formation by 26.4%. It indicates that about 94.5% of effluent CODMn values and nearly all of chloroform levels may meet the standard in normal period. However, Fe–Mn enhanced coagulation shows limitation in polluted period. The advanced treatment by ozone-biological activated carbon process (O3-BAC) increases the CODMn removal efficiency by 29.5%, and decreases the chloroform formation by 43%, indicating that effluent levels may meet the standard both in normal and polluted periods. Cost was also compared, and the extra cost for Fe–Mn enhanced coagulation is only about 20% of that for O3-BAC. In conclusion, O3-BAC works well both in normal and polluted periods. Fe–Mn enhanced coagulation only shows good performance in normal period, but is more economical. Therefore, it is proposed to use Fe–Mn enhanced coagulation in normal period, while O3-BAC during polluted period. These obtained plant-scale data are valuable to optimize the operation of DWTPs with similar challenges.

Treatment of Raw Water in Yangtze Chenhang Reservoir by Diatomaceous Earth Precoat Filtration

Taking the raw water of Yangtze Chenhang Reservoir as the research object, the characterization of diatomaceous earth, and the removal efficiency of CODMn, turbidity by precoat filtration process were investigated by pilot experiment in this paper. The results showed that diatomaceous earth patterns having porous structure and the pure silica peak at 2θ angles 21.980, 36.080, 31.460 and 28.430 in XRD analysis. Precoat filtration has a good stability to remove solid suspended particle, effluent turbidity was remained about 0.05NTU. Precoat filtration had no effect on removing CODMn. The pressure of 50KPa could be defined as a critical point in this experiment. Beyond the critical point, the devices should be stop and backwash, to resume operation pressure. Overall, precoat filtration can be defined as a filtration technique for relatively low turbidity raw waters.

기존하수처리장에서 자성체 이온교환수지를 이용한 하수처리공정 적용가능성 평가

The optimal removal efficiency to develop wastewater treatment system using the magnetic ion exchange resin. The secondary sedimentation effluent of wastewater in W wastewater treatment plant located in Gyeong-gi Province was used as the influent. To compare the sedimentation effluent reacted with the magnetic ion exchange resin to the influent, the concentrations of CODmm, TN, NO<SUB>3--</SUB>N and TP were measured. The flux of the influent and HRT were set to 250 mL/min, 10 min, respectively, and BVTR has adjusted to 200, 150, 100. The removal efficiency of CODmn, TN, NO<SUB>3--</SUB>N and TP in the 200 BVTR from 71%, 40.37%, 46.34%, 42.03%, 150 BVTR from 55.22%, 37.83%, 50.38% 41.6% and 100 BVTR from 74%, 59.15%, 79.94%, 79.16%, respectively. The results on 200 BVTR, 150 BVTR, 100 BVTR tests show that 100 BVTR is the optimal factor capable of the highest rate of rejection of the organic material.

Study on Wastewater Contaminant Removal Efficiency by Carbon Fiber Ecological Grass

The aim of this study is to investigate the contaminant removal efficiency in wastewater when disposed by carbon fiber ecological grass. The paper analyzed the TN, TP, CODMn, NH4+-N and SS removal efficiency when used different dosage of carbon fiber ecological grass. The research results indicated that the contaminant removal efficiency at pH=8 is higher than pH=6, 7 and 9. When DO between 5.6 and 8, the TN, TP and NH4+-N removal efficiency has a highest level, the removal efficiency is 83.91%, 68.16% and 83.3% respectively. When DO between 8.1 and 10.7, the CODMn removal efficiency has a highest level, the removal efficiency is 57.93%. The stirring rate is important to the contaminant adsorption and removal. Consequently, selecting carbon fiber ecological grass in wastewater treatment is a good choice.

Treatment on low carbon-to-nitrogen micro-polluted water by layered biological aerated filter with floating and sunken media

In order to improve the TN removal efficiency on low carbon-to-nitrogen micro-polluted water, in this study, a layered biological aerated filter (L-BAF) was built. The results showed that the removal efficiency for CODMn, NH3-N, and TN was 71.6-90.3%, 99.8-99.9%, and 57.8-65.7%, respectively, when the C/N ratio was kept at 3 and the volumetric flow rate was 0.072 m(3) d(-1). The L-BAF could improve the TN removal efficiency by about 20% compared to a traditional process. The L-BAF and traditional process removal efficiency for NH3-N and CODMn were similar. The kinetic performance of the L-BAF indicated that the relationship of CODMn removal efficiency with the influent CODMn concentration could be described by ln(C/C0) = -(0.0023/Q0C0(0.9398))H.

Comparison of NOM removal and microbial properties in up-flow/down-flow BAC filter

The removal of natural organic matter (NOM) in term of CODMn by up-flow biologically activated carbon filter (UBACF) and down-flow biologically activated carbon filter (DBACF) was investigated in a pilot-scale test. The impacts of the molecular weight distribution of NOM on its degradation by the UBACF and DBACF were evaluated. The relationship between biodegradation and the microbial properties in the UBACF and DBACF were approached as well. The feed water of the UBACF and DBACF were pumped from the effluent of the rapid sand filtration (RSF) of Chengnan Drinking Water Treatment Plant (CDWTP), Huaian, Jiangsu Province, China. When the adsorption was the dominant mechanism of NOM removal at the initial stage of operation, the CODMn removal efficiency by the UBACF was lower than the DBACF. However, with the microbes gradually accumulated and biofilm formed, the removal of CODMn by the UBACF increased correspondingly to 25.3%, at the steady-state operation and was approximately 10% higher than that by the DBACF. Heterotrophy plate count (HPC) in the finished water of the UBACF was observed 30% higher than that of the DBACF. The UBACF effluent had higher concentration of detached bacteria whereas the DBACF harbored more attached biomass. The highest attached biomass concentration of the UBACF was found in the middle of the GAC bed. On the contrary, the highest attached biomass concentration of the DBACF was found on the top of the GAC bed. Furthermore, a total of 9479 reads by pyrosequencing was obtained from samples of the UBACF and DBACF effluents. The UBACF effluent had a more diverse microbial community and more even distribution of species than the DBACF effluent did. Alphaproteobacteria and Betaproteobacteria were the dominant groups in the finished water of the UBACF and DBACF. The higher organic matter removal by the UBACF was attributed to the presence of its higher biologically activity.

Full-Scale Application of Catalytic Ozonation for Drinking Water Treatment: Case Study in China

AbstractA combination process of biofiltration, conventional treatment, catalytic ozonation and upflow biological activated carbon (BAC) is adopted for treating micropolluted raw water in Guanjinggang waterworks in China, and the present investigation mainly focuses on the effect of catalytic ozonation on the performance of BAC and on water quality over a long period of 699 days. The quality of finished water produced by the combination process is found to fully meet the drinking water standard of China. The removal efficiency of CODMn by catalytic ozonation is usually in the range of 10–20%, and this removal efficiency is independent of the CODMn concentration of the influent and water temperature. Catalytic ozonation can enhance the biodegradability of the effluent, and favors the following BAC. Catalytic ozonation also removes some ammonia and transforms organic nitrogen into NH4+-N. A slight increase of turbidity and manganese ion levels after catalytic ozonation are also found in many cases. Overall,...

Effect on Bed Material Heights to the Performance of ZCBAF in the Treatment of Micro-Polluted Raw Water

The effect of bed material heights on treatment performance of pollutants from micro-polluted raw Water was studied in zeolite - Ceramics biological aerated filter(ZCBAF) technology. The test results showed the removal rate of CODMn, NH4+-N and UV254 will improve with the increase of media height, most of CODMn and UV254 were removed within the first 440mm , when the media height over 440mm, the effect of increase height is inconspicuous removal, and ammonia-nitrogen removal has evident improvement during 220-440mm. At the media height of 20mm, 40mm and 60mm in ZCBAF respectively, the removal efficiency of CODMn is 18.05%，31.6% and 38.62% respectively, NH4+-N removal efficiency is 29.78%,81.28% and 93.02% respectively , and UV254 removal efficiency is 7.81%，10.11% and 11.26% respectively under the air/water ratio of 1:1 and the hydraulic loading of 1.2m3/(m2.h). Removal rate of CODMn was decreased with the increase of hydraulic loading, and removal effect of NH4+-N and UV254 had not big influence.

Experimental Study on Water Purification by Combination Processes of KMnO&lt;sub&gt;4&lt;/sub&gt; Pre-Oxidation and Flotation-Sedimentation Tank

Low temperature and low turbidity surface water is difficult to be treated using the traditional water treatment process, especially microamount organic matter and odor compounds in the water is hardly to be removed. The aim of this paper was to study the removal effects of treating reservoir water derived from Yellow River by combination processes of KMnO4 pre-oxidation and flotation-sedimentation tank. The results showed that the best dosage of KMnO4 was 0.3mg/L and removal efficiency of CODMn, UV254 and turbidity after KMnO4 pre-oxidation was 20.52%, 20.17% and 13.88%, especially. The combination processes have the advantage of treating the surface water at low temperature and low turbidity

Pretreatment of micro-polluted surface water with a biologically enhanced PAC–diatomite dynamic membrane reactor to produce drinking water

Abstract This study developed a biologically enhanced powder activated carbon (PAC) diatomite dynamic membrane reactor (BPDDMR) to pretreat micro-polluted surface water for drinking water production at lab-scale in continuous mode. In the start-up operation period, the BPDDMR required approximately 26 and 31 d to achieve stable removal efficiency of CODMn and NH3–N, respectively. Turbidity was always below 0.5 NTU throughout the operation experiment in the permeate flux range of 21−54lm−2 h−1. The BPDDMR could effectively remove the hydrophilic portion of dissolved organic materials (DOM) present in the raw water. The temperature affected pollutant removal (especially CODMn), which was mainly ascribed to microbial degradation and was also enhanced by PAC and diatomite adsorption. During the precoating period, the stainless steel support mesh (aperture 74 μm) first intercepted the large PAC (50−100 μm), and then diatomite particles (5−20 μm) were intercepted to form a two-layer structure of the biologicall...

Pretreatment of Micro-Polluted Raw Water by Parallel Process of Photocatalysis-Biological Contact Oxidation

By using parallel process of photocatalysis-biological contact oxidation, a research on the pretreatment effect of micro-polluted raw water was conducted. The result indicates that the changes of HRT and the initial concentration take significant impact on the removal of NH3-N. 60min is the best residence time for the pretreatment. Once the thickness of composite media is 120mm, the removal efficiency of CODMn may reach as much as 15.55%, while the average removal efficiency of turbidity is 20%. Since the nitration reaction consumes certain amount of alkalinity, the pH value of outlet water is lower than inlet water. When employing parallel process, biological oxidation and photocatalysis are performed and finished in the same reactor simultaneously, conducing to maintaining a moderate level of the removal of CODMn and NH3-N. All these are of reference value for its application in practical engineering projects.

Study on Production Wastewater in Water Treatment Plants by Submerged Micro-Filtration Membrane

To verify the feasibility of micro-filtration membrane process to treat the water treatment plants production wastewater, a submerged polypropylene membrane module was applied in a test pilot plant. It was found that membrane process had remarkable characteristics of stable operation, high water quality and the membrane module were needed to chemical medicine washing as trans-membrane pressure (TMP) to 36 Kpa after running across 41day. The operation cycle was the best period for 20 minutes (filter 18 minutes, backwash 2 minutes). Membrane filtration water was showed as turbidity of 0.1-0.2NTU, CODMn generally less than 3mg / L, CODMn removal efficiency of 60% -80%.Fe2 +, Mn2 +,Al3 + and THMFP of membrane filtration water were lower than the national drinking water health standards.