scholarly journals Characteristics of phosphorus sorption at the sediment–water interface in Dongting Lake, a Yangtze-connected lake

2016 ◽  
Vol 47 (S1) ◽  
pp. 225-237 ◽  
Author(s):  
Wei Huang ◽  
Kun Wang ◽  
Hongwei Du ◽  
Ting Wang ◽  
Shuhang Wang ◽  
...  
Keyword(s):  
Fine Particles ◽  
Sorption Isotherms ◽  
Physicochemical Characteristics ◽  
Dongting Lake ◽  
Phosphorus Concentration ◽  
Phosphorus Sorption ◽  
Sediment Samples ◽  
Low Phosphorus ◽  
Phosphorus Source ◽  
Sorption Characteristics

Phosphorus in sediments plays an important role in lake eutrophication. This study investigated the phosphorus sorption characteristics of sediments in a river-connected lake and identified the phosphorus source or sink areas in the lake. Sediment samples with different physicochemical characteristics were collected in 2011 and 2013 from Dongting Lake, which is connected to the world's third longest river, the Yangtze. Batch incubation experiments were conducted to determine the phosphorus sorption characteristics of the sediment samples. The sediment sample from Luzui (D3) exhibited the highest sorption capacity in 2013 (0.75 mg g−1) because of its large proportion of fine particles (<63 μm). Results of sorption isotherms illustrated that the modified Langmuir model can effectively describe the sorption isotherms (R2 > 0.91). The calculated results (equilibrium phosphorus concentration, 0.025–0.032 mg L−1) indicated that the estuary from Dongting Lake to the Yangtze River (D1) served as a phosphorus sink because of the large proportion of fine particles and low total phosphorus content in the sediments. The east Dongting Lake (D2 and D3) with a high phosphorus concentration served as a phosphorus source. Yugong Miao (D4) and Nanzui (D5) had a low phosphorus concentration in water because of their location and flow field, respectively.

The effect of anaerobic zone mixing on the performance of a three-stage Bardenpho plant

1998 ◽  
Vol 38 (1) ◽  
pp. 55-62 ◽  
Author(s):  
S. C. Williams ◽  
J. Beresford
Keyword(s):  
Detrimental Effect ◽  
Flow Characteristic ◽  
Tracer Tests ◽  
Poor Performance ◽  
Phosphorus Concentration ◽  
Effluent Quality ◽  
Mixing Energy ◽  
The United Kingdom ◽  
Low Phosphorus ◽  
Anaerobic Zone

Thames Water have built a three-stage Bardenpho activated sludge plant to treat 50% of the wastewater flow at Slough in the United Kingdom. Following commissioning, the plant performed well in terms of nitrification and denitrification but did not produce an effluent with a low phosphorus concentration. One possible explanation for the poor performance was the mixing of the anaerobic zone. The flow characteristic of the anaerobic zone was identified by tracer tests and alternative mixing regimes were tested. The results showed that reducing the mixing energy in the anaerobic zone had no detrimental effect on the effluent quality. The plant has operated with the reduced mixing input for nine months and the effluent phosphorus concentration has been reduced from 2.1 mgl−1 to 0.8 mgl−1.

Phosphorus sorption characteristics and related properties in urban soils in southeast China

CATENA ◽  
2019 ◽  
Vol 175 ◽  
pp. 349-355 ◽  
Author(s):  
Zongqiang Wei ◽  
Xiao Yan ◽  
Zhihong Lu ◽  
Jianfu Wu
Keyword(s):  
Urban Soils ◽  
Phosphorus Sorption ◽  
Southeast China ◽  
Sorption Characteristics

scholarly journals Homemade bone charcoal adsorbent for defluoridation of groundwater in Thailand

2010 ◽  
Vol 8 (4) ◽  
pp. 826-836 ◽  
Author(s):  
Sunisa Smittakorn ◽  
Nithat Jirawongboonrod ◽  
Surat Mongkolnchai-arunya ◽  
Deanna Durnford
Keyword(s):  
Sorption Isotherms ◽  
Bone Char ◽  
Batch Experiments ◽  
First Order ◽  
Social Resistance ◽  
Bone Charcoal ◽  
The Social ◽  
The World ◽  
Fresh Bone ◽  
Sorption Characteristics

High levels of fluoride in groundwater are a significant environmental and health problem in Thailand, as in many parts of the world. Small household defluoridators have several advantages over centralized treatment systems. In Thailand, however, use of bone char for water treatment has met resistance because of objectionable taste and odours of the water produced and the social resistance to handling fresh bone. This paper presents a method that uses bone charcoal as an absorbent for removing fluoride from groundwater. The commercially provided boiled bone is burned in a simple homemade furnace that can be constructed, operated and maintained easily by small rural householders. The method to produce the Thai bone char eliminates the odour and objectionable taste and also does not require the user to handle fresh bone, thus eliminating the social resistance. To evaluate the efficacy of the absorbent, batch experiments compare Thai and Indian bone char. Sorption isotherms are fit to the Freundlich and Langmuir equations and the kinetics are modelled using the pseudo first-order Lagergren equation. Results show that the sorption characteristics of Thai bone char compare favourably with the Indian bone char, with approximately 80% of the fluoride removed in both cases.

scholarly journals Low-Temperature Rheological Properties and Microscopic Characterization of Asphalt Rubbers Containing Heterogeneous Crumb Rubbers

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4120 ◽  
Author(s):  
Mingfeng Chang ◽  
Yixing Zhang ◽  
Jianzhong Pei ◽  
Jiupeng Zhang ◽  
Min Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Rheological Properties ◽  
Fine Particles ◽  
Physicochemical Characteristics ◽  
Crumb Rubber ◽  
Rubber Content ◽  
Evaluation Indexes ◽  
Asphalt Rubber ◽  
Linear Viscoelastic Material ◽  
Microscopic Morphology

Asphalt rubbers mixed with untreated and plasticized crumb rubbers and a compounding coupling agent were investigated in this study. The low-temperature rheological properties of asphalt rubbers at different aging levels were tested using a dynamic shear rheometer (DSR). An interconversion between linear viscoelastic material functions was used to obtain converted evaluation indexes for the asphalt rubbers at low temperatures. Lastly, the physicochemical characteristics and the microscopic morphology of the asphalt rubbers were evaluated using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), respectively. In conclusion, the storage moduli of the asphalt rubbers containing heterogeneous crumb rubbers increased with the plasticized crumb rubber content and the aging level. The converted relaxation moduli were consistent with the change trend of the storage moduli, and the relaxation rate decreased as the plasticized crumb rubber content and the aging level increased. The process of mixing the base asphalt with crumb and plasticized crumb rubbers was physical blending, and the effect of aging on the absorption peak change of asphalt rubber with plasticized crumb rubbers was less than that of asphalt rubber with ordinary crumb rubbers. Aging deteriorated the blending between the crumb rubber and the base asphalt, and a distinct interface appeared between the crumb rubber and the base asphalt. The particle cores of the plasticized crumb rubber in the asphalt rubber were difficult to maintain. Furthermore, as the plasticized crumb rubber content increased, more fine particles stripped off the plasticized crumb rubber after aging.

scholarly journals Effect of manure types on phosphorus sorption characteristics of an agricultural soil in Bangladesh

2016 ◽  
Vol 2 (1) ◽  
Author(s):  
Nureza Hafiz ◽  
Shirajum Monira Adity ◽  
Sadia Farah Mitu ◽  
Atikur Rahman
Keyword(s):  
Agricultural Soil ◽  
Phosphorus Sorption ◽  
Sorption Characteristics

Water sorption properties inCoffeaspp. seeds and embryos

1999 ◽  
Vol 9 (4) ◽  
pp. 321-330 ◽  
Author(s):  
Mirian T.S. Eira ◽  
Christina Walters ◽  
Linda S. Caldas
Keyword(s):  
Water Sorption ◽  
Sorption Isotherms ◽  
Plant Tissues ◽  
Orthodox Seeds ◽  
Water Sorption Properties ◽  
Low Levels ◽  
Coffee Seed ◽  
Excised Embryos ◽  
Sorption Characteristics ◽  
Water Sorption Isotherms

The relationships among water content, relative humidity and temperature were documented in both seeds and excised embryos ofCoffeaspp. using water sorption isotherms. Isotherms were constructed at 5, 15 and 25°C and calculated for lower temperatures. There were no apparent differences in sorption characteristics among whole seeds of several cultivars ofC. arabicaand among different species ofCoffea. Excised embryos of genetically diverseCoffeagermplasm also exhibited similar sorption characteristics, though there were substantial differences observed between embryos and whole seeds. The shape of isotherms of coffee seed tissues was intermediate to the reverse sigmoidal shape observed for orthodox seeds and the monotonic shape observed for desiccation intolerant plant tissues. The heats of sorption calculated for RH ≤ 25% for whole seeds ofCoffeaspp. were similar to orthodox seeds. In contrast, the heats of sorption calculated in the same RH range for excised embryos were intermediate between those of orthodox and recalcitrant embryos. Our observations are consistent with earlier observations that desiccation sensitivity or poor longevity is linked with low levels of water sorption at relative humidities less than 25%. An explanation for this remains elusive.

Sign in / Sign up

Export Citation Format

Share Document