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1.
Environ Sci Process Impacts ; 22(1): 217-226, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31898705

RESUMO

In the rhizosphere, plant root exudates can mediate the toxicity of antibiotics on microorganisms, yet the mechanisms are poorly understood. To simulate the antibiotic contamination of global rivers and lakes, the current study investigated the effects of two antibiotics (ofloxacin at 8.69 × 104 ng L-1 and tetracycline at 8.62 × 104 ng L-1) and their binary combination (8.24 × 104 ng L-1 ofloxacin and 7.11 × 104 ng L-1 tetracycline) on bacterial communities in micro-polluted constructed wetlands with and without artificial root exudates. The two antibiotics had no significant effects on the removal of excess carbon and nitrogen from the microcosms treated with and without exudates. Furthermore, with regard to bacterial community structure, antibiotic exposure increased the bacterial richness of bulk and exudate treated microcosms (P < 0.05). However, a significant increase (P < 0.05) in bacterial diversity elicited by ofloxacin and antibiotic mixture exposure was only observed in microcosms with exudates. In exudate treated microcosms, ofloxacin promoted the relative abundance of Arthrobacter spp., which are ofloxacin-resistant bacterial species, which significantly varied from what was observed in microcosms free of exudates. Moreover, tetracycline, ofloxacin and their combination all significantly increased the relative abundance of nitrogen cycling bacteria Rhizobacter spp. and Rhizobium spp., and decreased the relative abundance of antibiotic-resistant bacteria Pseudomonas spp. Simultaneously, with regard to bacterial community functions, the functional profiles (Kyoto Encyclopedia of Genes and Genomes) showed that the pathways of amino acid and carbohydrate metabolism were enhanced by antibiotics in microcosms with exudates. The findings illustrate that antibiotics not only alter the bacterial structure and composition but also change their functional properties in constructed wetlands, and these interruption effects could be affected by root exudates of plants, which may further reveal the ecological implication of plants in constructed wetlands.


Assuntos
Antibacterianos , Microbiota , Rizosfera , Áreas Alagadas , Antibacterianos/toxicidade , Microbiota/efeitos dos fármacos , Nitrogênio , Raízes de Plantas/microbiologia
2.
Environ Monit Assess ; 191(6): 365, 2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31089888

RESUMO

Accurately measuring and estimating trends and variations in nutrient levels is a significant part of managing emerging eutrophic lakes in developing countries. This study developed an integrated approach containing Seasonal Trend Decomposition using Loess (STL) and a dynamic nonlinear autoregressive model with exogenous input (NARX) network to decompose and estimate the nutrient concentrations in Lake Erhai, a preliminary eutrophic lake in China. The STL decomposition results indicated that total nitrogen (TN) concentration of Lake Erhai progressively descended from 2006 to 2014, except for some agriculture area. The total phosphorus (TP) concentration showed an increasing trend from 2006 to 2013 and then decreased in 2014, but in the area near the tourist attractions, TP increased continuously from 2011 to 2014. Seasonal variations in TN and TP indicated that the lowest water quality of Lake Erhai occurred from July to October. Based on results obtained with STL, TP was selected as the sensitive parameter, as it showed a significant deterioration trend, and the area near the tourist attractions was selected as the sensitive area. Three variables (DO, pH, and water temperature) were selected as input parameters to estimate TP using the dynamic NARX model. The NARX modeling results demonstrated that it can accurately estimate TP concentrations with low root-mean-square error (0.0071 mg/L). The study establishes a new approach to better understand trends and variations in nutrient levels and to better refine estimates by identifying more easily accessible physical parameters in a preliminary eutrophic lake.


Assuntos
Monitoramento Ambiental/métodos , Eutrofização , Modelos Químicos , Poluentes Químicos da Água/análise , Poluição Química da Água/estatística & dados numéricos , Agricultura , China , Lagos/química , Nitrogênio/análise , Fósforo/análise , Estações do Ano , Temperatura , Qualidade da Água
3.
Water Environ Res ; 91(9): 843-854, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30844095

RESUMO

Throughout rural regions, large amounts of domestic wastewater are discharged into natural bodies of water without treatment. A well-designed subsurface wastewater infiltration (SWI) system is an effective wastewater pollution removal strategy for small and remote communities due to its low energy consumption, low operational cost, and good performance. This paper describes the types of structures and purification mechanisms of SWI systems, focusing on the design of substrate materials and the optimization of different operation modes including the hydraulic loading rate, pollutant loading rate, intermittent operation, aeration, and shunting distribution. The challenges and trends in the development of SWI systems are also discussed. PRACTITIONER POINTS: The construction and purification mechanisms of SWI system are described. The design of substrates and the optimization of operation modes are focused. The challenges and the development trends for the system are further introduced.


Assuntos
Águas Residuárias , Purificação da Água , Nitrogênio , Eliminação de Resíduos Líquidos
4.
Environ Sci Pollut Res Int ; 26(11): 10621-10630, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30762179

RESUMO

To investigate the effects of antibiotics on nitrogen removal and uptake by wetland plants, four typical macrophyte species, Cyperus alternifolius L., Typha angustifolia L., Lythrum salicaria L., and Acorus calamus L., were grown in hydroponic cultivation systems and fed wastewater polluted with 10 µg L-1 Ofloxacin (OFL) and Tetracycline (TET). Biomass production, nitrogen mass concentration, chlorophyll content, root exudates, and nitrogen removal efficiency of hydroponic cultivation were investigated. The results indicated that in all hydroponic systems, NH4+-N was entirely removed from the hydroponic substrate within 1 day and plant nitrogen accumulation was the main role of the removed NO3-. OFL and TET stimulated the accumulation of biomass and nitrogen of A. calamus but significantly inhibited the NO3--N removal ability of L. salicaria (98.6 to 76.2%) and T. augustifolia (84.3 to 40.2%). This indicates that A. calamus may be a good choice for nitrogen uptake in wetlands contaminated with antibiotics. OFL and TET improved the concentrations of total organic carbon (TOC), total nitrogen (TN), organic acid, and soluble sugars in root exudates, especially for oxalic acid. Considering the significant correlation between TOC of root exudates and nitrogen removal efficiency, the TOC of root exudates may be an important index for choosing macrophytes to maintain nitrogen removal ability in wetlands contaminated with antibiotics.


Assuntos
Acorus/efeitos dos fármacos , Antibacterianos/farmacologia , Cyperus/efeitos dos fármacos , Lythrum/efeitos dos fármacos , Nitrogênio/metabolismo , Typhaceae/efeitos dos fármacos , Acorus/crescimento & desenvolvimento , Acorus/metabolismo , Transporte Biológico/efeitos dos fármacos , Biomassa , Cyperus/crescimento & desenvolvimento , Cyperus/metabolismo , Hidroponia , Lythrum/crescimento & desenvolvimento , Lythrum/metabolismo , Nitrogênio/análise , Ofloxacino/análise , Ofloxacino/farmacologia , Typhaceae/crescimento & desenvolvimento , Typhaceae/metabolismo , Águas Residuárias/química , Poluentes da Água/análise , Poluentes da Água/farmacologia , Áreas Alagadas
5.
Sci Total Environ ; 656: 503-511, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30522033

RESUMO

Constructed wetlands (CWs) have emerged as a promising technology for the purification of micro-polluted water. However, their nitrogen removal performance can be significantly degraded by design, operational, and environmental factors. The present study investigates the effects of ofloxacin (OFL: 0.1, 10, and 1000 µg L-1) and plants (Cyperus alternifolius L. and Typha angustifolia L.) on nitrogen removal in a micro-polluted CW system over a duration of 12 weeks. The effects were evaluated by investigating NH4-N and NO3-N removal efficiency, nitrification genes (amoA-AOA and amoA-AOB), denitrification genes (nirK and nirS), fungal 18S rRNA gene and microorganism community structure. The results showed that in unplanted CWs, OFL increased the NH4-N removal efficiency (from 72.6% to 80.7-82.1%), the abundances of amoA-AOA, nirS, nirK and fungal 18S rRNA gene, and the bacterial diversity but decreased the abundance of both amoA-AOB and bacterial richness. In contrast, both the nitrogen removal efficiency (83.4-89.5% for NH4-N and 33.8-38.5% for NO3-N) and bacterial diversity/richness were not significantly affected by OFL in planted CWs. In planted systems, OFL increased the relative abundance of Arthrobacter, Pseudomonas, and Enterococcus, which are proven antibiotic-resistant bacteria. This study showed that CWs are able to remove nitrogen from antibiotic-contaminated micro-polluted water, which might primarily be attributed to the presence of plants that protect the microorganism community.


Assuntos
Cyperus/metabolismo , Microbiota , Nitrogênio/metabolismo , Ofloxacino/metabolismo , Typhaceae/metabolismo , Poluentes Químicos da Água/metabolismo , Antibacterianos/metabolismo , Cyperus/microbiologia , Genes Bacterianos , Typhaceae/microbiologia , Eliminação de Resíduos Líquidos , Áreas Alagadas
6.
Sci Total Environ ; 607-608: 676-682, 2017 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-28709102

RESUMO

Bisphenol A (BPA) has caused widespread concern among scholars as a result of its estrogenic toxicity. It exists mainly in natural waters, sediments, and soil, as well as sewage and wastewater sludge. Considering that BPA is a common environmental pollutant that is removed along with chemical oxygen demand (COD), nitrogen, and phosphorus in drainage treatment systems, it is important to research the fate of BPA in sewage treatment systems. In this research, laboratory batch experiments on soil degradation and adsorption were conducted with 14C-BPA, aiming to discuss the transport and degradation characteristics of BPA in both simulated facilities and a soil trench. Based on the experimental results, the Freundlich model could be applied to fit the isothermal adsorption curve of the BPA in soil. A low mobility characteristic of BPA was discovered. The mineralization rate of BPA was fast and that of the reaction showed small fluctuations. After degradation, 21.3 and 17.7% of the BPA groups (the experimental group treated with ammonia oxidase (AMO) inhibitor and the control group) were converted into 14CO2, respectively. This indicates that the nitrification and degradation of BPA had a certain competitive relationship. Besides, nitrification did not significantly affect the soil residue of BPA. Through the soil trench test, the average removal rate of BPA in the soil trench was 85.5%. 14CO2 was discharged via the mineralization of BPA, accounting for 2.5% of the initial input. BPA easily accumulated in the bottom soil of the soil trench. BPA and its metabolites in the effluent accounted for 14.5% of the initial dosage. The residual extractable BPA and its metabolites in the soil accounted for 51.3%, and the remaining part of the unextractable residue represented 19.8% of the initial radioactive dosage.

7.
Sci Total Environ ; 598: 697-703, 2017 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-28456121

RESUMO

In micro-polluted constructed wetland (CW), the low pollutant concentrations and the low COD/N ratios (chemical oxygen demand: total nitrogen in influent), make the biological treatment more difficult. It is expected that root exudates drive microbial-based transformations within plant rhizosphere. In this research, the roles of root exudates of three aquatic plants (Phragmites australis, Typha angustifolia and Cyperus alternifolius) in improving the growth of heterotrophic denitrifying bacteria were determined in a micro-polluted CW. In studied root rhizospheres, the total organic carbon (TOC) released from the plant roots varied significantly among plant species and seasons; the average TOC ranged from 0.1715 to 0.9221mgg-1rootDMd-1, which could fuel a denitrification rate of approximately 156-841kgNO3--Nha-1year-1 if all were used by the denitrifying bacteria; the abundances of nirK- and nirS-encoding bacteria were significantly influenced by the concentration of sucrose and glucose (0.869≤r≤0.933, p<0.05), and microbial community richness and diversity had response to root exudates. The results revealed that root exudates can act as endogenous carbon sources for heterotrophic denitrifying bacteria and ultimately determine the microbe distribution patterns in micro-polluted CW.


Assuntos
Desnitrificação , Exsudatos de Plantas/química , Raízes de Plantas/química , Microbiologia da Água , Áreas Alagadas , Bactérias , Análise da Demanda Biológica de Oxigênio , Cyperaceae , Nitrogênio/análise , Poaceae , Rizosfera , Typhaceae
8.
J Nanosci Nanotechnol ; 16(1): 802-6, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27398526

RESUMO

In this study Er³âº doped CaMoO4 (CaMoO4:Er³âº), and Er³âº/Yb³âº-co-doped CaMoO4 (CaMoO4:Er³âºYb³âº) nanoparticles have been synthesized by the microwave-assisted metathetic method. Er³âº/Yb³âº co-doped CaMoO4 nanoparticles sintered at 600 °C showed the strongest photoluminescence intensity, and crystallized well. At the excitation of 980 nm, the CaMoO4 nanoparticles show the strongest green emission at the 520 nm and 550 nm emission bands. Moreover, the green light produced has a better color purity.


Assuntos
Cálcio/química , Érbio/química , Fluorescência , Micro-Ondas , Molibdênio/química , Itérbio/química
9.
J Hazard Mater ; 190(1-3): 848-55, 2011 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-21530079

RESUMO

Phosphate removal from wastewater is very important for the prevention of eutrophication. Adsorption of phosphate from water was investigated using activated carbon fiber loaded with lanthanum oxide (ACF-La) as a novel adsorbent. The effects of variables (La/ACF mass ratio, impregnation time, activation time, and activation temperature) have been studied by the single-factor method. Response surface methodology (RSM), based on three-variable-three-level Box-Behnken design (BBD), was employed to assess the individual and collective effects of the main independent parameters on the phosphate removal. The optimal conditions within the range studied for preparing ACF-La were found as follows: La/ACF mass ratio of 11.78%, activation time of 2.5h and activation temperature at 650°C, respectively. The phosphate removal using the ACF-La prepared under the optimal conditions was up to 97.6% even when the phosphate concentration in water was 30 mgP/L, indicating that ACF-La may be an effective adsorbent. The results from Fourier transform infrared (FT-IR) spectroscopy and change of pH values associated with the adsorption process revealed that the probable mechanism of phosphate ions onto ACF-La was not only ion exchange and coulomb interaction, but also a result of Lewis acid-base interaction due to La-O coordination bonding.


Assuntos
Carbono/química , Carvão Vegetal/química , Lantânio/química , Óxidos/química , Fosfatos/isolamento & purificação , Purificação da Água/métodos , Adsorção , Fibra de Carbono
10.
Biomed Environ Sci ; 23(1): 48-52, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20486436

RESUMO

OBJECTIVE: To investigate the effect of iron on the growth, physiology and photosynthesis of cyanobacteria. METHODS: A gradient of iron concentrations was employed to investigate the growth, photo-pigments (chlorophyll A and phycocyanin), and cell chemical contents (C, N, P) of Microcystis aeruginosa in response to different iron additions. RESULTS: The specific growth rate during the exponential growth phase, as well as the cell chlorophyll A and the phycocyanin content, was limited by iron below 12.3 tmol Fe x L(-1). The growth was inhibited when the iron concentration was at 24.6 micromol Fe x L(-1). The cell chlorophyll A and the phycocyanin content were saturated when the iron concentration was above 12.3 micromol Fe x L(-1) and declined slightly at 24.6 micromol Fe x L(-1). At a low iron concentration (about 6.15 micromol Fe x L(-1) and less), the cell nitrogen and carbohydrate content were iron limited, and the variation of the cell phosphorus content was similar to that of the nitrogen and carbohydrate, with a transition point of 12.3 micromol Fe x L(-1). CONCLUSION: The variation of cynobacteria growth is synchronous with that of the photo-pigments or the cell chemical content, and there exist relationships among photosynthesis, growth and internal chemical content, which could be useful for the growth estimation from the cell characteristics.


Assuntos
Ferro/farmacologia , Microcystis/efeitos dos fármacos , Microcystis/fisiologia , Carboidratos/análise , Meios de Cultura/química , Relação Dose-Resposta a Droga , Microcystis/química , Microcystis/citologia , Nitrogênio/análise , Fósforo/análise
11.
J Hazard Mater ; 167(1-3): 244-9, 2009 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-19185993

RESUMO

Zeolitic materials were synthesized from thermally treated sediment by alkali treatment using different NaOH/sediment ratios. Characterization of the materials was done by XRD, FTIR, cation exchange capacity and specific surface area. Use of high NaOH/sediment ratio favored the formation of zeolite. The potential value of the zeolitic materials for the retention of trivalent chromium from water was examined. The maximum of Cr(III) sorption by the zeolitic materials, determined by a repeated batch equilibration method, ranged from 38.9 to 75.8 mg/g which was much greater than that of the thermally treated sediment (6.3 mg/g). No release of sorbed Cr(III) by 1.0M MgCl(2) at pH 7 was observed but Cr(III) desorption by ionic electrolyte increased with decreasing pH. The zeolitic materials could completely remove Cr(III) from wastewater even in the presence of Na(+) and Ca(2+) with high concentrations with a dose above 2.5 g/L. The pH-dependent desorption behavior and the high selectivity of zeolitic material for Cr(III) were explained by sorption at surface hydroxyl sites and formation of surface precipitates.


Assuntos
Cromo/isolamento & purificação , Resíduos Industriais/prevenção & controle , Poluentes Químicos da Água/isolamento & purificação , Zeolitas/química , Adsorção , Sedimentos Geológicos , Temperatura Alta , Concentração de Íons de Hidrogênio
12.
J Environ Sci (China) ; 21(12): 1632-8, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-20131591

RESUMO

A cyanobacterial (Arthrospira platensis) bloom was induced in situ by nutrient manipulation in an enclosure. The succession of the phytoplankton community and the water chemistry variations before the appearance of bloom, as well as their relationship, were investigated. The cell pigment variations were studied simultaneously. The Pearson's correlation analysis showed that there was no significant correlation between water chemistry and green algal or cyanobacterial composition, indicating that water chemistry variations were not suitable to be used as indicators for cyanobacterial-bloom early-warning. However, the diversity index of the phytoplankton community decreased sharply before the bloom appeared. Therefore, the dynamics of phytoplankton community was put forward to be an indicator for cyanobacterial-bloom early-warning. In addition, the cell pigment variations represented the changes of community structure, which should be useful for studying the dynamics of phytoplankton community.


Assuntos
Cianobactérias , Ecossistema , Proliferação Nociva de Algas , Fitoplâncton , Água/química , Clorofila/análise
13.
Ying Yong Sheng Tai Xue Bao ; 20(11): 2813-9, 2009 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-20136021

RESUMO

Harmful algal bloom (HAB) occurs frequently and causes serious damage. To study the early-warning and prediction technology of HAB is of significance for the early-warning and prediction, ecological control, and disaster prevention and mitigation of HAB. This paper reviewed the research progress in the early-warning and prediction technologies of HAB, including transport prediction, specific factors critical value prediction, data-driven model, and ecological math model, and evaluated the advantages and disadvantages of these four types of technologies. Some new ideas were brought forward about the prediction of cyanobacterial growth rate based on cell characteristics, and the early-warning of cyanobacterial bloom based on algal community characteristics.


Assuntos
Monitoramento Ambiental/métodos , Proliferação Nociva de Algas , Modelos Teóricos , Poluentes da Água/análise , Cianobactérias/crescimento & desenvolvimento , Ecossistema , Previsões , Água Doce/microbiologia , Modelos Biológicos
14.
J Environ Sci (China) ; 21(5): 575-80, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-20108657

RESUMO

Xonotlite was synthesized and tested for phosphate removal and recovery from synthetic solution in a batch mode. The effects of pH, initial calcium concentration, bicarbonate concentration on phosphate removal through crystallization were examined. The morphology and X-ray diffraction (XRD) pattern of xonotlite before and after crystallization confirmed the formation of crystalline hydroxyapatite. The results indicated that the crystallization product had a very high P content (> 10%), which is comparable to phosphate rock at the dosage of 50-200 mg xonotlite per liter, with a maximum P content of 16.7%. The kinetics of phosphate removal followed the second-order reaction equation. The phosphate removal ability increased with increasing pH. The precipitation of calcium phosphate took place when pH was higher than 7.2, whereas the crystallization occurred at pH 6.0. A high calcium concentration could promote the removal of phosphate via crystallization, while a high bicarbonate concentration also enhanced phosphate removal, through that the pH was increased and thus induced the precipitation process. When xonotlite was used to remove phosphate from wastewater, the removal efficiency could reach 91.3% after 24 h reaction, with removal capacity 137 mg/g. The results indicated that xonotlite might be used as an effective crystal seed for the removal and recovery of phosphate from aqueous solution.


Assuntos
Compostos de Cálcio/química , Durapatita/química , Fosfatos/isolamento & purificação , Silicatos/química , Cristalização , Cristalografia por Raios X , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Varredura
15.
J Hazard Mater ; 155(3): 415-23, 2008 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-18178311

RESUMO

The capability of 14 zeolites synthesized from different fly ashes (ZFAs) to sequestrate Cr(III) from aqueous solutions was investigated in a batch mode. The influence of pH on the sorption of Cr(III) was examined. ZFAs had a much greater ability than fly ash to remove Cr(III), due to the high cation exchange capacity (CEC) and the high acid neutralizing capacity (ANC) of ZFAs. The mechanism of Cr(III) removal by ZFAs involved ion exchange and precipitation. A high-calcium content in both the fly ashes and ZFAs resulted in a high ANC value and, as a result, a high immobilization capacity for Cr(III). The pH strongly influenced Cr(III) removal by ZFAs. Inside the solubility range, removal of chromium increased with increasing pH. Hydroxysodalite made from a high-calcium fly ash had a higher sorptive capacity for Cr(III) than the NaP1 zeolite from medium- and low-calcium fly ashes. On the other hand, at pH values above the solubility range, the efficiency of chromium removal by the ZFAs approached 100% due to the precipitation of Cr(OH)3 on the sorbent surfaces. It is concluded that ZFAs and high-calcium fly ashes may be promising materials for the purification of Cr(III) from water/wastewater.


Assuntos
Carbono , Cromo/isolamento & purificação , Carvão Mineral , Material Particulado , Zeolitas/síntese química , Ácidos , Cinza de Carvão , Concentração de Íons de Hidrogênio , Soluções , Água
16.
Artigo em Inglês | MEDLINE | ID: mdl-16854801

RESUMO

The paper describes the quality of water source in Shanghai, China and its water supply system. The effect of purification by traditional water treatment process and the effluent biological stability were evaluated by measuring quality parameters in the water supply system. The data showed that the main pollutants in the water source of Huangpu River were organics and ammonia. The conventional water treatment process is not effective to remove these pollutants. Concentrations of nitrite, nitrate, ammonia and UV254 are affected by the water distribution system (DS). The effect is more obvious especially for nitrate and UV254. In addition, the turbidity and chroma increased along the water supply system. The data obtained in this study show the extent of biological instability of drinking water in Shanghai.


Assuntos
Poluição da Água/prevenção & controle , Abastecimento de Água/normas , Amônia/análise , China , Cloro/análise , Água Doce/análise , Nefelometria e Turbidimetria , Nitratos/análise , Nitrogênio/análise , Eliminação de Resíduos Líquidos , Microbiologia da Água , Poluição da Água/efeitos adversos , Abastecimento de Água/análise
17.
Huan Jing Ke Xue ; 27(1): 95-100, 2006 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-16599128

RESUMO

Factors affecting biological process for removing iron and manganese in groundwater were analyzed. When DO and pH in groundwater after aeration were 7.0 - 7.5 mg/L and 6.8 - 7.0 respectively, not only can the activation of Mn2+ oxidizing bacteria be maintained, but also the demand of iron and manganese removal can be satisfied. A novel inoculating approach of grafting mature filter material into filter bed, which is easier to handle than selective culture media, was employed in this research. However, this approach was only suitable to the filter material of high-quality manganese sand with strong Mn2+ adsorption capacity. For the filter material of quartz sand with weak adsorption capacity, only culturing and domesticating Mn2+ oxidizing bacteria by selective culture media can be adopted as inoculation in filter bed. The optimal backwashing rate of biological filter bed filled with manganese sand and quartz sand should be kept at a relatively low level of 6 - 9 L/(m2 x s) and 7 -11 L/( m2 x s), respectively. Then the stability of microbial phase in filter bed was not disturbed, and iron and manganese removal efficiency recovered in less than 5h. Moreover, by using filter material with uniform particle size of 1.0 - 1.2 mm in filter bed, the filtration cycle reached as long as 35 - 38h.


Assuntos
Bactérias/metabolismo , Ferro/metabolismo , Manganês/metabolismo , Poluentes da Água/metabolismo , Purificação da Água/métodos , Ferro/análise , Manganês/análise , Poluentes da Água/análise , Abastecimento de Água/análise
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