Vertical distribution pattern of naidids in granular activated carbon filters and potential technology to control their penetration risk

2018 ◽  
Vol 18 (6) ◽  
pp. 1976-1983
Author(s):  
Xiao-Bao Nie ◽  
Yun-Zi Tang ◽  
Chang-bo Jiang ◽  
Yuan-Nan Long ◽  
Pan-Pan He ◽  
...  

Abstract Aquatic worms propagated in granular activated carbon (GAC) filter has become a troublesome problem for drinking water supply. This study investigated the vertical distribution patterns of naidids in GAC filter beds and assessed the effect of an additional sand bed, located below the GAC bed, in preventing naidids from being present in effluent. The results indicated that the vertical distribution data of naidids in the GAC filter bed were well fitted by a Gaussian distribution, and the location of peak population density was mainly affected by downward flow. Backwashing experiments revealed that additional pressure air scouring shifted the distribution pattern of naidids in the GAC filter bed, resulting in a significant enhancement in naidid removal efficiency. Additionally, the addition of a sand bed exhibited pronounced interception and inactivation effects on naidids, suggesting that it may be a very promising technology for preventing naidids propagated in GAC filters from being present in the effluent.

e-xacta ◽  
2013 ◽  
Vol 6 (2) ◽  
pp. 1
Author(s):  
Flávia Sayuri Arakawa ◽  
Quelen Letícia Shimabuku ◽  
Priscila Ferri Coldebella ◽  
Franciele Pereira Camacho ◽  
Fernando Alves Silva ◽  
...  

<p align="justify">O carvão ativado granular impregnado com zinco (C/Zn) foi avaliado em relação à atividade antibacteriana para eliminação de micro-organismos na purificação de água para consumo humano. Os meios filtrantes produzidos a partir de C/Zn foram caracterizados através de técnicas instrumentais como análises de BET e difração de raios-X (DRX) para determinar a distribuição de poros e área superficial e as fases estruturais, respectivamente. Experimentos foram realizados em um sistema doméstico de purificação de água utilizando filtros com leito de carvão ativado granular sem impregnação e com impregnação de zinco nas concentrações de 1,0, 3,0, 5,0 e 10,0% (m/m). A atividade antibacteriana dos meios filtrantes foi avaliada em relação à eficiência de remoção de bactérias Escherichia coli da água. Foram preparadas soluções sintéticas com água deionizada contaminada artificialmente com uma concentração aproximada entre 1,0x105 a 9,0x106 UFC/100mL de Escherichia coli. Assim a eficiência bacteriológica dos meios filtrantes com C/Zn foi superior com o aumento da concentração de zinco impregnado no carvão ativado. O filtro com leito de carvão ativado impregnado com 10% de zinco apresentou a maior eficiência com remoção de Escherichia coli superior a 99% e melhorando a qualidade bacteriológica da água para consumo humano.</p><p align="justify">Abstract</p><p align="justify">Granular activated carbon impregnated with zinc (C/Zn) was evaluated for the antibacterial activity for elimination of micro-organisms in drinking water purification. The filter media produced from C/Zn were characterized by instrumental techniques such as the BET analyzes and x-ray diffraction (XRD) to determine the pore distribution and surface area and structural phases, respectively. Experiments were performed in a household water purification system using filters with granular activated carbon bed without impregnation and impregnation with zinc in concentrations of 1.0, 3.0, 5.0 and 10.0% (w/w). The antibacterial activity of the filter media was evaluated regarding to the removal efficiency of bacteria Escherichia coli of water. Synthetic solutions were prepared with deionized water contaminated artificially with an approximate concentration of 1.0 x105 to 9.0 x106 CFU/100mL of Escherichia coli. The efficiency bacteriological efficiency bacteriological of filter media with C/Zn was higher with increasing concentration of zinc impregnated on activated carbon.The filter bed of activated carbon impregnated with 10% of zinc showed the highest efficiency with removal of bacterial Escherichia coli higher than 98% and improving the bacteriological quality of drinking water.</p>


2021 ◽  
Author(s):  
Wentong Gao ◽  
Qitong Wang ◽  
Xiaoming Zhu ◽  
Zhanfeng Liu ◽  
Na Li ◽  
...  

Abstract Background and aimsWhile the quantitative assessment of plant- and microbial-derived carbon (C) in the soil organic C (SOC) chemical composition in soil profiles has been initially explored, the vertical distribution pattern of these two C sources and their dominant role in SOC formation based on the insights related to the rhizosphere are still lacking.MethodsWe quantified the divergent accumulation of microbial-derived C (i.e., microbial residues), plant-derived C (i.e., lipids and lignin phenols) and SOC in the rhizosphere at various depths (0-10 cm, 10-20 cm and 20-30 cm) in the upper mineral soil and analyzed its control factors in an alpine coniferous forest (Picea asperata. Mast). We further revealed the relative contribution of plant- or microbial-derived C to rhizosphere SOC in the soil profile.ResultsThe contents of microbial- and plant-derived C and SOC in the rhizosphere decreased with soil depth and were mainly regulated by root and microbial biomass. Moreover, the contribution of microbial-derived C dominated by fungal residues to rhizosphere SOC at each soil depth (more than 62%) was much higher than that of plant-derived C (less than 6%), implying that the soil microbial C pump was intensely stimulated in the rhizosphere.ConclusionsThese results indicated that microbial-derived C was the main contributor of rhizosphere SOC at various depths in the upper mineral soil. Our findings provide direct experimental evidence for assessing the dominant contribution of microbial- or plant-derived C to SOC in the soil profile from the perspective of the rhizosphere.


2009 ◽  
Vol 66 (6) ◽  
pp. 1289-1295 ◽  
Author(s):  
Takeshi Nakamura ◽  
Akira Hamano

Abstract Nakamura, T., and Hamano, A. 2009. Seasonal differences in the vertical distribution pattern of Japanese jack mackerel, Trachurus japonicus: changes according to age? – ICES Journal of Marine Science, 66: 1289–1295. The Japanese jack mackerel, Trachurus japonicus, is commercially and ecologically one of the most important fishery resources in Japanese waters. A clear understanding of the age-dependent, vertical distribution pattern is important for the effective and sustainable management of this resource. In this study, acoustic surveys were conducted from June to November 2001 in the western Sea of Japan to clarify seasonal differences. The survey area included a number of artificial reefs at depths >100 m. To identify fish species and determine the characteristics of the water column, simultaneous biological sampling and oceanographic surveys were carried out. The vertical distribution of Japanese jack mackerel varied with their age and size and between seasons. In June and July, aggregations of juvenile (age 0; <10 cm in length) Japanese jack mackerel were found in a layer between 20 and 50 m deep associated with a temperature range of 19–21°C. However, the age-0 aggregations were not observed from August to November. Conversely, the age-1+ schools aggregated around the artificial reefs when the temperature was <19°C. It is suggested that there are seasonal differences in the vertical distribution pattern between the early life and adult stages of Japanese jack mackerel. Because of the different vertical distributions of these life stages, acoustic backscatter information is useful for determining the age of the observed fish.


Author(s):  
O.J.I. Kramer ◽  
C. van Schaik ◽  
P.D.R. Dacomba-Torres ◽  
P.J. de Moel ◽  
E.S. Boek ◽  
...  

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