scholarly journals Developing Magnetic Material for Remediation of Aquatic Nitrogen Pollution in Water Facilities

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
Guocheng Zhu ◽  
Junming Chen

Natural organic matter affect water environmental security and posed a potential threat to human health, and thus it has long been considered as a key index to evaluate water treatment performance. Dissolved organic nitrogen is one of the NOM, which produces some disinfection byproducts having more toxic than those carbon-based materials. Coagulation is a key unit of drinking water purification and has received wide attention. However, conventional flocculation technology on removal of DON is so poor that we have to seek more effective improving measurement. The combined use of conventional flocculant and organic polymer can improve treatment efficiency to a certain extent, and enhanced coagulation can also improve the DON removal rate, but their DON removal performance is still not dreamful. At present, there is a lack of systematic research on flocculation to remove DON. Although some achievements have been made, there is still a big gap between the preparation technology of flocculant and the goal of efficient removal of DON in water.For treatment of secondary effluent of industrial wastewater, some studies show that the use of Fe3O4 mainly has the effect of accelerating separation, but the adsorption effect is not good. However, with the synergistic flocculation of amino functionalized Fe3O4 it has a good effect on removing water protein, polysaccharide and humic acid, which can meet the water quality discharge standard and reduce the dosage of flocculant. The above results show that functional nanoparticle materials are of great significance to improve the adsorption and flocculation performance. Therefore, the functional modification of magnetic nanoparticles plays an important role.

2012 ◽  
Vol 433-440 ◽  
pp. 4751-4756 ◽  
Author(s):  
Hao Wu ◽  
Zi Fu Li ◽  
Xin Jin ◽  
Xin Zhao ◽  
Fu Rong Deng

Secondary effluent from WWTPS still contains a large number of microorganisms, therefore, disinfection is essential. There are many disadvantages in using traditional disinfection methods, so the combination of disinfection techniques is a new research direction. Ozone combined with ultrasound is one of them. In this experiment, the inactivation of the total coli forms, color removal and UV254 removal of secondary effluent by a combination of ultrasonic (frequency20 kHz; power100W) and ozone disinfection was investigated. The results show that the effect of the synergistic action of 30s US and ozone disinfection is superior to the effect of individual ozone disinfection. After 15min synergistic disinfection, the total coli forms inactivation rate is up to 99.9%, simultaneously color removal rate to 80% and UV254 removal rate to 52%. Compared with individual ozone disinfection, reaction time was reduced by 5 min.


Nanoscale ◽  
2020 ◽  
Vol 12 (47) ◽  
pp. 24044-24053
Author(s):  
Jie Zhang ◽  
Lihong Zhou ◽  
Zhimin Jia ◽  
Xiaofeng Li ◽  
Yue Qi ◽  
...  

A new type of COF with a double-ring pore shows a size-matching adsorption effect for uranium with removal rate up to 99.8%.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Zhaoqian Jing ◽  
Shiwei Cao

To enhance the biodegradability of residual organic pollutants in secondary effluent of wastewater treatment plants, UV photolysis and ozonation were used in combination as pretreatment before a biological aerating filter (BAF). The results indicated that UV photolysis could not remove much COD (chemical oxygen demand), and the performance of ozonation was better than the former. With UV photolysis combined with ozonation (UV/O3), COD removal was much higher than the sum of that with UV photolysis and ozonation alone, which indicated that UV photolysis could efficiently promote COD removal during ozonation. This pretreatment also improved molecular weight distribution (MWD) and biodegradability greatly. Proportion of organic compounds with molecular weight (MW) <3 kDalton was increased from 51.9% to 85.9%. COD removal rates with BAF and O3/BAF were only about 25% and 38%, respectively. When UV/O3oxidation was combined with BAF, the average COD removal rate reached above 61%, which was about 2.5 times of that with BAF alone. With influent COD ranging from 65 to 84 mg/L, the effluent COD was stably in the scope of 23–31 mg/L. The combination of UV/O3oxidation with BAF was quite efficient in organic pollutants removal for tertiary wastewater treatment.


1999 ◽  
Vol 122 (1) ◽  
pp. 55-61 ◽  
Author(s):  
B. K. Subhas ◽  
R. Bhat ◽  
K. Ramachandra ◽  
H. K. Balakrishna

Inconel 718 alloy is used extensively in aerogas turbines and this alloy is most difficult to machine and highly prone to dimensional instability after machining. Such detrimental phenomenon poses an enormous problem in engine assembly and affects structural integrity. This paper highlights the systematic research work undertaken to study the plastic deformation characteristics of Inconel 718, and the effect of process variables on machined surface, subsurface, and dimensional instability. Also illustrated is the technique developed for simultaneous optimization of several process variables such as cutting speed, feed, depth of cut, rake angle, and tool nose radius to control the residual stresses and dimensional instability within the acceptable tolerance band of the component. Prediction equations were developed for residual stress, dimensional instability, tool life, surface finish, and material removal rate. Predicted data were validated experimentally. This paper also presents the qualitative and quantitative data on dimensional instability with specific case studies of jet engine components, and it clearly illustrates the approach followed to develop a technique to control such detrimental effect. [S0742-4795(00)00901-7]


2013 ◽  
Vol 295-298 ◽  
pp. 1231-1234 ◽  
Author(s):  
Yong Gui Yang ◽  
Yun Long Yang ◽  
Xiao Hong Kang

An experiment on the removal of heavy metal copper ions from industrial wastewater by magnetic flocculation was studied and the influences of PFS dosage static sedimentation time,temperature,pH value and magnetic powder dosage on treatment effect were discussed at the same time .The result of the test showed that when the dosage of PFS and magnetic powder were 100 and 400 mg/l respectively the pH value was 8.0,the static sedimentation time was 20min, the said process had a good effect on copper containing wastewater treatment. The removal rate of copper ions was over 97%,and the mass concentration of copper ions in the effluent water was below 0.5mg/l. Therefore after be treated by magnetic flocculation the quality of copper-containing wastewater could meet the requirement of GB 8978-1996 Integrated Wastewater Discharge Standard .


2011 ◽  
Vol 374-377 ◽  
pp. 1170-1178
Author(s):  
Jian Yang ◽  
Jiang Chang ◽  
Yi Ping Gan ◽  
Jin Hua Gao

The primary objective of this research was to evaluate the effectiveness of a magnetic ion exchange process (MIEX) in removing inorganic anions from municipal secondary effluent. Municipal secondary effluent drew from Gaobeidian wastewater treatment plant treating about 800,000 m3/day domestic wastewater. In the pilot experiment, MIEX resin removed 37.01% phosphorus, 31.62% nitrate, 36.06% ammonium and 64.34% sulphate from municipal secondary effluent. Phosphorus concentration in resin influent influenced reclaimed water treatment efficiency. Phosphorus removal rate was positively correlated with the concentration in influent. If phosphorus concentration in influent was >0.82mg/L, phosphorus removal of >52% was achieved. Nitrate and sulphate removal had same variation laws. 18.92% average removal rate of nitrate in middle period was lower than 35.06% and 39.25% average removal rates in earlier and latter periods respectively. The average removal rates of ammonium in three periods were 83.03%, 43.51% and 84.29% respectively. Removed ammonium of each sample was about 0.250mg/L, average removal rate was 36.06%. Lower ammonium concentration in influent could cause higher removal rate. Otherwise, magnetic ion exchange process could increase turbidity and could not disinfect, the resin effluent will be treated with coagulation-sedimentation and ozonation for groundwater recharge research with reclaimed water.


2013 ◽  
Vol 361-363 ◽  
pp. 601-605
Author(s):  
Ji Ku Zhang ◽  
Yang Yang Li ◽  
Chen Zhang ◽  
Yan Bin Yang

By treating the secondary effluent of Sanbaotun sewage treatment plant in Fushun with the CS type UV Sterilizer, the experiment researches the influence on the removal rate which includes the factors of turbidity, chromaticity, initial E.coli concentration of raw water, UV dose. The results show that the turbidity does not influence on UV disinfection efficiency with the turbidity from 1.5NTU to 3.8NTU. In the low-dose UV disinfection process, the influent sewage turbidity should under 4NTU to ensure the disinfection efficiency. Low chromaticity does not affect the UV disinfection efficiency, with the influent sewage chromaticity is under 15 degrees.The initial E. coli has a certain impact on little doses of UV disinfection with the concentration from 175 × 104 A/ L to 230 × 104 A/ L, no impact on high doses of UV disinfection。


2013 ◽  
Vol 821-822 ◽  
pp. 1193-1199
Author(s):  
Zhi Liang ◽  
Tong Jie Wei ◽  
Hu Kun Wang ◽  
Xi Kun Liu ◽  
Ming Long Hong ◽  
...  

The process conditions of making composite particle adsorption material out of hydroxyapatite-chitosan, regeneration method, and how to use composite particle adsorption material to treat industrial sewage containing heavy metals are researched. Experiment consequence shows that when the mass ratio of chitosan to hydroxyapatite is 0.12:1, the concentration of acetic acid is 4%, and liquid-solid ratio is 0.6:1, the granular material will be produced with the best adsorption effect. The dosage of composite particle adsorption material is 0.025 g/mL, the adsorption time is 60 min, and the temperature is 25 °C , removal percentage of Cd2+, Pb2+ and Zn2+ is 99.25%, 75.16% and 79.33% respectively. The isothermal adsorption equation is CCd/Q = 1.323CCd+ 0.1338. Adsorption selective sequence is: Cd2+ > Zn2+ >Pb2+ . When we use 1 mol/L NaCl to regenerate composite particle adsorption material, it still can be employed to deal with sewage with a good effect.


Author(s):  
Liyuan Chen ◽  
Dapeng Li ◽  
Yong Huang ◽  
Wenjuan Zhu ◽  
Yuqin Ding ◽  
...  

Abstract This study sought a new way to utilize sludge as a low cost and efficient adsorbent. Preparation of sludge adsorbent by hydrothermal carbonization was done at different temperatures (160–250 °C). Various characterization techniques were used in this study including elemental analysis, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The adsorption performance of the organic matter was analyzed by adsorption experiments with the endocrine disruptor bisphenol A (BPA). Results showed that as the hydrothermal temperature increased, the solid yield of hydrochar decreased from 84.73% to 55.19%, and the maximum specific surface area was 11.9 m2/g. Elemental analysis showed that the hydrochar contains more aromatic carbon than the raw sludge. It was found using the FT-IR and XPS that the hydrochar retains a large amount of oxygen-containing functional groups on the surface after hydrothermal treatment. Hydrochar can be used as an organic-pollutant adsorbent in water; it has a good adsorption effect on BPA and the removal rate can reach 96%. The adsorbed hydrochar can be hydrothermally retreated and returned to the sewage treatment plant for reuse.


2007 ◽  
Vol 55 (1-2) ◽  
pp. 59-67 ◽  
Author(s):  
X.C. Wang ◽  
H.L. Yuan ◽  
Y.J. Liu ◽  
P.K. Jin

A pilot-scale fluidised pellet bed (FPB) bioreactor, which combines chemical coagulation, biological degradation, particle pelletisation and separation in one unit, was applied for onsite wastewater treatment and reuse. As a result of rational use of inorganic coagulant and organic polymer and moderate mechanical agitation, spherical particles were generated in the upflow column and a well-fluidised bed was formed. With a continuous supply of dissolved oxygen through a recycling loop, an aerobic condition was kept in the bottom section of the FPB column. Under such conditions the pellets in the FPB column showed the following characteristics: (1) compact structure and high density; (2) rich in microorganisms; and (3) high MLSS and MLVSS concentrations. Therefore, the FPB bioreactor achieved more than 90% removal of SS, COD, BOD and TP from raw domestic wastewater within a total hydraulic retention time (HRT) of only about 30 minutes. It also showed nitrification and denitrification ability and the TN removal could be about 50% as the recycling ratio was increased to 1:1. The treated water quality is generally competitive with the secondary effluent from a conventional activated sludge process. With these advantages the FPB bioreactor is recommendable as a compact system for onsite wastewater treatment and reuse.


Sign in / Sign up

Export Citation Format

Share Document