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1

Polishing of secondary effluent by a two-stage vertical-flow constructed wetland

100%
Zhang C., Tan S., Li J., Peng C.
Polish Journal of Environmental Studies
|
2015
|
tom 24
|
nr 2
A two-stage vertical-flow constructed wetland (VFCW) was built to advanced treatment of secondary effluent containing organic and inorganic nutrients (nitrogen and phosphorus) from a municipal sewage treatment plant in Beijing, China. The results showed that the VFCW effluent achieved 66-83% and 81-90% removal for COD and TP, respectively. Meanwhile, NH₄⁺-N and TN were almost completely removed during stable operation of the wetland system. The VFCW effluent concentrations of COD, TN, and TP were less than 30 mg·L⁻¹, 1.5 mg·L⁻¹, and 0.3 mg·L⁻¹, respectively, which can meet the environmental quality standards for surface water in China. Because of the special design, the better performance of the VFCW was that it allowed the treatment of wastewater under multiple aerobic, anoxic, and anaerobic conditions sequentially in different heights of the CW unit. New media materials, rice husks, and steel slag were the key to the efficient removal of TN and TP. This technology could be adopted to improve the secondary effluent quality.
2

Past and future trends of wastewater treatment in Beijing

100%
Zhang C., Peng C., Li J.
Polish Journal of Environmental Studies
|
2015
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tom 24
|
nr 2
An analysis is made on the past and future trends of wastewater treatment in Beijing. Over the past several decades, great efforts have been made by Beijing to improve the urban wastewater treatment technology, reclaim municipal wastewater, and promote water reclamation and reuse. Until now, the utilization volume of reclaimed water has been increasing continuously. Generally, there are four categories of wastewater treatment plants (WWTPs) in Beijing. And the most mainstream wastewater treatment method in Beijing is aerobic biological process, thereinto the advanced treatment methods of WWTPs, including membrane bioreactor (MBR), biological aerated filter (BAF), and chemical oxidation. However, both the existing conventional and advanced treatment processes mainly aim at the remediation of COD, ammonia nitrogen, total nitrogen, total phosphorus, and other conventional organic pollutants. Micro pollutants such as persistent organic pollutants (POPs) are not considered in the design of WWTPs. The treatment and disposal issues of sludge have become an important agenda item for Beijing’s municipal government. In the future, the priority technologies for wastewater treatment in Beijing should have the features of high efficiency and stability, and lower energy consumption, and operational cost. Suitable small-scale technologies are necessary for rural areas. The existing wastewater treatment facilities must be strengthened and improved to reduce the micro-pollutants in wastewater.
3

Resondes of chlorophyll fluorescence and xanthophyll cycle in leaves of Schima superba Gardn. and Champ. and Pinus massoniana Lamb. to simulated acid rain at Dinghushan Biosphere Reserve, China

88%
Liu J., Zhou G., Yang C., Ou Z., Peng C.
Acta Physiologiae Plantarum
|
2007
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tom 29
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nr 1
Schima superba and Pinus massoniana distributed over large areas in southern China both are dominant species at Dinghushan Biosphere Reserve. In the present study, the changes of chlorophyll fluorescence and xanthophyll cycle in the leaves of S. superba and P. massoniana exposed to simulated acid rain (SAR) were measured. When exposed to high light, the PSII photochemistry efficiency (Fv/Fm), efficiency of energy conversion in PSII (ΦPSII) and photochemical quenching (qP) of both S. superba and P. massoniana all decreased when acidity of SAR increased. Regarding non-photochemical quenching (qN), S. superba exposed to SAR had higher value than control plants, but there was no significant difference between the respective seedlings of P. massoniana. As for xanthophyll cycle of the two plant species, the leaves of S. superba exposed to SAR showed a higher content of carotenoids and a higher ability to convert violaxanthin to zeaxanthin than leaves of P. massoniana, which was consistent with S. superba exhibiting a stronger resistance to high light than P. massoniana. Although both species were susceptible to acid rain as shown by our results, P. massoniana was more susceptible compared to S. superba. These results provide an insight into how to protect the forest ecosystem at Dinghushan Biosphere Reserve.
4

Physiological and cellular responses to fluoride stress in tea (Camellia sinensis) leaves

76%
Cai H., Dong Y., Li Y., Li D., Peng C., Zhang Z., Wan X.
Acta Physiologiae Plantarum
|
2016
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tom 38
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nr 06
5

Meta-analysis of the effects of soil warming on soil respiration in forest ecosystems

76%
Sun J., Peng C., Onge B. S., Berninger F., McCaughey H., Lei X.
Polish Journal of Ecology
|
2011
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tom 59
|
nr 4
No consensus has emerged on the sensitivity of soil respiration to increasing temperatures under global warming due partly to the lack of data and unclear feedbacks. Our objective was to investigate the general trends of warming effects on soil respiration. This study used meta-analysis as a means to synthesize data from eight sites with a total of 140 measurements taken from published studies. The results presented here suggest that average soil respiration in forest ecosystems was increased approximately by 22.5% with escalating soil temperatures while soil moisture was decreased by 16.5%. The decline in soil moisture seemed to be offset by the positive effects of increasing temperatures on soil respiration. Therefore, global warming will tend to increase the release of carbon normally stored within forest soils into the atmosphere due to increased respiration.
6

Interactive effect of radioactive and heavy-metal contamination on soil enzyme activity in a former uranium mine

64%
Yang G., Dong F., Liu M., Nie X., Zong M., Peng C., Chen H., Wei H., Wang P., Zhang W.
Polish Journal of Environmental Studies
|
2018
|
tom 27
|
nr 3
Radioactivity and heavy metal toxicity of multi-metal deposits coexisting with the element uranium (U) could have long-term adverse impacts on soil biological processes and the health of soil ecosystems. Soil enzyme activities are considered bioindicators for assessing soil health. An experiment was designed to investigate invertase and ß-glucosidase activity in multi-metal deposits. Radioactivity and heavy metals were also investigated during this study. Our results showed that the invertase and ß-glucosidase activities were significantly lower in the core mining area than the control area (p<0.05). Activities of the two enzymes decreased with increasing metal concentrations and radioactivity. Cu and Zn showed significant negative effects on ß-glucosidase and invertase activities in a multi-metal deposit at the study site. A significant nonlinear relationship was recorded between soil enzyme activities, radiation dose (R² = 0.71, 0.63; p<0.05), Zn (R² = 0.34, 0.41; p<0.05) and Cu concentrations (R² = 0.46, 0.45; p<0.05). There were turning points at 1 μGy h⁻¹, 250 μg g⁻¹, and 30 μg g⁻¹ for radiation dose, Zn and Cu contents, respectively. The findings could provide more information regarding the toxic effects of radiation and heavy metals on the soil health of multi-metal deposits, which can more precisely guide environmental protection.
7

Variations of sediment archaea communities in different distribution areas of Bruguiera gymnoihiza Mangrove in Dongzhaigang, China

64%
Li W., Guan W., Chen H., Liao B., Hu J., Rui J., Peng C., Zhu D., He Y., Tian J.
Polish Journal of Environmental Studies
|
2019
|
tom 28
|
nr 5
Archaea communities widely exist in mangrove forest sediments, but their spatial variations among different distribution areas with salinity gradient in mangrove forest sediments is not well understood. This study used 16S rRNA Miseq sequence to investigate the sediment archaeal community structure and diversity of Bruguiera gymnoihiza mangrove forest in China along three different distribution areas. The results showed rich methanogen and ammonia-oxidizing archaea resources in the study site, with Methanobacterium, Methanothrix, Methanomassiliicoccus, Nitrosopumilus and Nitrososphaera (>1%) as the dominant genera. Mantel test and Redundancy analysis (RDA) results revealed that pH was the determinant for archaeal community structure in our study. The RDA result showed that the available K also contributed to archaeal community structure. There was a significant and positive relationship between pH and available P; in addition, the two values were significantly and negatively related to the observed OTU number. These results suggested that pH is the main determinant of the archaeal community structure and diversity in distribution areas of Bruguiera gymnoihiza in Dongzhaigang.
8

Forecasting carbon budget under climate change and CO2 fertilization for subtropical region in China using Integrated Biosphere Simulator (IBIS) model

64%
Zhu Q., Jiang H., Liu J., Peng C., Fang X., Yu S., Zhou G., Wei X., Ju W.
Polish Journal of Ecology
|
2011
|
tom 59
|
nr 1
The regional carbon budget of the climatic transition zone may be very sensitive to climate change and increasing atmospheric CO2 concentrations. This study simulated the carbon cycles under these changes using process-based ecosystem models. The Integrated Biosphere Simulator (IBIS), a Dynamic Global Vegetation Model (DGVM), was used to evaluate the impacts of climate change and CO2 fertilization on net primary production (NPP), net ecosystem production (NEP), and the vegetation structure of terrestrial ecosystems in Zhejiang province (area 101,800 km2, mainly covered by subtropical evergreen forest and warm-temperate evergreen broadleaf forest) which is located in the subtropical climate area of China. Two general circulation models (HADCM3 and CGCM3) representing four IPCC climate change scenarios (HC3AA, HC3GG, CGCM-sresa2, and CGCM-sresb1) were used as climate inputs for IBIS. Results show that simulated historical biomass and NPP are consistent with field and other modelled data, which makes the analysis of future carbon budget reliable. The results indicate that NPP over the entire Zhejiang province was about 55 Mt C yr-1 during the last half of the 21st century. An NPP increase of about 24 Mt C by the end of the 21st century was estimated with the combined effects of increasing CO2 and climate change. A slight NPP increase of about 5 Mt C was estimated under the climate change alone scenario. Forests in Zhejiang are currently acting as a carbon sink with an average NEP of about 2.5 Mt C yr–1. NEP will increase to about 5 Mt C yr–1 by the end of the 21st century with the increasing atmospheric CO2 concentration and climate change. However, climate change alone will reduce the forest carbon sequestration of Zhejiang’s forests. Future climate warming will substantially change the vegetation cover types; warm-temperate evergreen broadleaf forest will be gradually substituted by subtropical evergreen forest. An increasing CO2 concentration will have little contribution to vegetation changes. Simulated NPP shows geographic patterns consistent with temperature to a certain extent, and precipitation is not the limiting factor for forest NPP in the subtropical climate conditions. There is no close relationship between the spatial pattern of NEP and climate condition.
9

Identification and elucidation of the designing and operational issues of trickling filter systems for wastewater treatment

64%
Ali I., Khan Z. M., Peng C., Naz I., Sultan M., Ali M., Mahmood M. H., Niaz Y.
Polish Journal of Environmental Studies
|
2017
|
tom 26
|
nr 6
Water pollution has become a major environmental concern for public and environmental health in developing countries. Water resources are being contaminated mainly due to mixing of domestic, municipal, and industrial wastewaters. The wastewater management and treatment situation is deplorable mainly because of financial constraints, the unavailability of technically trained human resources, and electricity shortages. Moreover, there is a challenge for the scientific community and wastewater management experts to explore cost-effective, simple, reliable, and efficient wastewater treatment systems. Therefore, the present review highlights the option of trickling filter (TF) systems for wastewater treatment in developing countries like Pakistan, India, Bangladesh, and African regions, etc. In addition, the solutions to the operational/performance issues of the TF system are explored and discussed in greater detail for designing/construction of new TF systems and retrofitting the existing TFs.
10

Removal of Crystal violet and Eriochrome black T dyes from aqueous solutions by magnetic nanoparticles biosynthesized from leaf Extract of Fraxinus chinensis Roxb

64%
Ali I., Peng C., Khan Z. M., Sultan M., Naz I., Ali M., Farid H. U., Mahmood M. H., Ahsen R.
Polish Journal of Environmental Studies
|
2019
|
tom 28
|
nr 4
In the present research, a “green” recipe was used to produce innovative phytogenic magnetic nanoparticles (PMNPs) from leaf extract of Fraxinus chinensis Roxb without employing any additional toxic surfactants as capping agents. The convenient reaction between metal salt solution and plant biomolecules occurred within a few minutes by color changes from pale green to intense black, hinting at the production of magnetic nanoparticles (MNPs). The formation of PMNPs was verified by employing different techniques such as UV-visible spectrophotometry, Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray (EDX). The fabricated PMNPs were further utilized as a catalyst for removing toxic dyes, i.e., Crystal violet (CV) and Eriochrome black T (EBT) from aqueous solutions in the presence of hydrogen peroxide (H2O2). The concentrations of CV and EBT were calculated using ultraviolet-visible (UV-vis) spectroscopy throughout all the experiments. The results indicated that PMNPs showed >95% removal of both dyes within 10 min of contact time over a wide range of concentration, 10-300 mg/L. The degradation kinetics were also investigated using first- and second-order rate equations, and the results indicated that kinetic data of both CV and EBT followed first-order degradation rate. Moreover, the removal efficiency of the fabricated PMNPs was alsocompared with chemically synthesized magnetic nanoparticles (CSMNPs), and the results indicated that our fabricated PMNPs were more effective in terms of extent and speed to remove dyes. Finally, we have also proposed a possible removal mechanism. Altogether, the developed “green” recipe can easily be implemented to produce potentially biocompatible and non-toxic PMNPs for treatment of wastewater and can also easily be employed in low-economy countries.
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