Inactivation of Chironomid larvae with ozone

2008 ◽  
Vol 8 (3) ◽  
pp. 355-361 ◽  
Author(s):  
Xing-Bin Sun ◽  
Fu-Yi Cui
Keyword(s):  
Contact Time ◽  
Ph Value ◽  
Inactivation Rate ◽  
Raw Water ◽  
Organic Precursor ◽  
Chironomid Larvae ◽  
Complete Inactivation ◽  
Jar Test ◽  
Coagulation Process ◽  
Inactivation Efficiency

In this paper, comparative experiments on the inactivation of Chironomid larvae by ozone and chlorine were conducted. In addition, batch experiments were performed in order to analyze the influence of pH value, organic precursor concentration and temperature on the inactivation efficiency of Chironomid larvae with ozone. Based on it, removal effect of different pre-oxidation combined with coagulation process on Chironomid larvae in raw water was evaluated. The results showed that ozone possessed better inactivation performance than chlorine, and complete inactivation of Chironomid larvae in raw water was obtained at ozone dose of 2.0 mg/L after 25 minutes of contact time. The inactivation rate of Chironomid larvae at pH 6.0 was higher than those found at pH 8.0 in same contact time. Meanwhile, the organic precursor had negative effects on inactivation, indicated by the decreasing inactivation rate from 100% at TOC concentration of 0 mg/L to 20.0% at 8 mg/L after 30 min of contact time. With regard to the temperature, the inactivation efficiency of Chironomid larvae improved with the temperature increasing within the range investigated of 10–25°C. The inactivation rate was reduced by 73.3% when temperature reduced from 25°C to10°C. The coagulation jar test showed that Chironomid larvae in the raw water could be completely removed by ozone pre-oxidation combined with the coagulation process at ozone dosage of 1.2 mg/L.

scholarly journals Inactivation of Escherichia coli and Staphyloccocus aureus in Litchi Juice by Dimethyl Dicarbonate (DMDC) Combined With Nisin

2014 ◽  
Vol 3 (3) ◽  
pp. 1 ◽  
Author(s):  
Yuanshan Yu ◽  
Yujuan Xu ◽  
Jijun Wu ◽  
Gengsheng Xiao ◽  
Jing Wen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Synergistic Effect ◽  
Ph Value ◽  
Inactivation Rate ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Complete Inactivation ◽  
Staphyloccocus Aureus ◽  
Addition Level

<p>Inactivation of Gram-negative <em>Escherichia coli</em> and Gram-positive <em>Staphyloccocus aureus</em> in litchi juice by DMDC combined with nisin was individually investigated. A 1.66 log cycles reduction of<em> E. coli </em>and 2.03 log cycles reduction of <em>S. aureus </em>in litchi juice (pH 4.5) added without nisin was achieved as exposed to 150 mg/l DMDC at 30 °C for 1 h, and the inactivation rate of <em>E. coli </em>and <em>S. aureus</em> during initial 1 h was far greater than during the remaining 5 h. As exposed to 150 mg/l DMDC at 30 °C for 1 h, the inactivation of <em>E. coli</em> and <em>S. aureus</em> in the litchi juice showed a trend toward increase with increasing of nisin addition level in the range from 0 to 200 IU/ml. Moreover, DMDC and nisin exhibited a synergistic effect on the inactivation of <em>E. coli</em> and <em>S. aureus</em> in litchi juice, and the inactivation of<em> E. coli</em> and <em>S. aureus</em> in the litchi juice also depends on the temperature of litchi juice, pH value of litchi juice and DMDC concentration when treated with DMDC and nisin. In addition, <em>E. coli</em> showed higher resistance to nisin as comparing with <em>S. aureus</em>. After <em>E. coli</em> and <em>S. aureus</em> in the litchi juice of pH 4.0 were individually treated with 150 mg/l DMDC combined with 200 IU/ml nisin at 30 °C for 1 h, a complete inactivation of <em>S. aureus</em> (6.59 log cycles) was achieved, but only 3.52 log cycles reduction of <em>E. coli</em> was observed.</p>

Synergic Removal on Chironomus kiiensis larvae in Urban Water Source with Pre-Oxidation

2010 ◽  
Vol 113-116 ◽  
pp. 735-739
Author(s):  
Xing Bin Sun ◽  
Fu Yi Cui ◽  
Zhao Chao Hou ◽  
Lin Meng
Keyword(s):  
Chlorine Dioxide ◽  
Removal Rate ◽  
Experimental Studies ◽  
Water Source ◽  
Raw Water ◽  
Sedimentation Process ◽  
Jar Test ◽  
Disinfection Process ◽  
Eutrophic Water ◽  
Inactivation Efficiency

Chironomus kiiensis larvae which cannot be exterminated by conventional disinfection process propagates prolifically in eutrophic water body, and it therefore turns to be a potential problem encountered in drinking water quality. In this work, the quantitative experimental studies were carried out on removal of Chironomus kiiensis larvae in raw water by coagulation-sedimentation process. The coagulation jar test showed that the Chironomus kiiensis larvae could be partially removed from water by coagulation-sedimentation process. Based on it, removal effect of pre-oxidation combined with coagulation-sedimentation process on Chironomus kiiensis larvae was evaluated. The results showed that chlorine dioxide pre-oxidation possessed better removal performance than prechlorinion, and Chironomus kiiensis larvae in the raw water could be completely removed by chlorine dioxide pre-oxidation in combination with the coagulation-sedimentation process at chlorine dioxide dosage of 0.8mg/L. The pH in the range of 6-8 did not affect the inactivation efficiency of chlorine dioxide, whereas pH 10 resulted in around 10% decrease in removal rate. Meanwhile, the removal rate of Chironomus kiiensis larvae improved with the temperature increasing within the range investigated of 15-30°C. The removal rate was reduced by 6.7% when temperature reduced from 30°C to 15°C.

Control of coagulation process by dual wavelength article analyzer

1997 ◽  
Vol 36 (4) ◽  
pp. 135-142 ◽  
Author(s):  
Norihito Tambo ◽  
Yoshihiko Matsui ◽  
Ken-ichi Kurotani ◽  
Masakazu Kubota ◽  
Hirohide Akiyama ◽  
...  
Keyword(s):  
Water Quality ◽  
Control System ◽  
Predictive Control ◽  
Control Method ◽  
Feedforward Control ◽  
Raw Water ◽  
Floc Size ◽  
Coagulation Process ◽  
Series Of Experiments ◽  
Size Data

A coagulation process for water purification plants mainly uses feedforward control based on raw water quality and empirical data and requires operator's help. We developed a new floc sensor for measuring floc size in a flush mixer to be used for floc control. A control system using model predictive control was developed on the floc size data. A series of experiments was performed to confirm controllability of settled water quality by controlling flush mixer floc size. An automatic control with feedback from the coagulation process was evaluated as practical and reliable. Finally this new control method was applied for actual plant and evaluated as practical.

Nano-ZrO2/TiO2 Impregnated Orange Wood Sawdust and Peach Stone Shell Adsorbents for Cr (VI) Removal

2020 ◽  
Vol 16 (7) ◽  
pp. 880-892
Author(s):  
Şerife Parlayıcı ◽  
Kübra Tuna Sezer ◽  
Erol Pehlivan
Keyword(s):  
Contact Time ◽  
Ph Value ◽  
Order Kinetic ◽  
Adsorption Parameters ◽  
Wood Sawdust ◽  
Adsorption Data ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Equilibrium Status

Background: In this work, Cr (VI) adsorption on nano-ZrO2๏TiO2 impregnated orange wood sawdust (Zr๏Ti/OWS) and nano-ZrO2๏TiO2 impregnated peach stone shell (Zr๏Ti/PSS) was investigated by applying different adsorption parameters such as Cr (VI) concentrations, contact time, adsorbent dose, and pH for all adsorbents. Methods: The adsorbents were characterized by SEM and FT-IR. The equilibrium status was achieved after 120 min of contact time and optimum pH value around 2 were determined for Cr (VI) adsorption. Adsorption data in the equilibrium is well-assembled by the Langmuir model during the adsorption process. Results: Langmuir isotherm model showed a maximum adsorption value of OWS: 21.65 mg/g and Zr๏Ti/OWS: 27.25 mg/g. The same isotherm displayed a maximum adsorption value of PSS: 17.64 mg/g, and Zr๏Ti/PSS: 31.15 mg/g. Pseudo-second-order kinetic models (R2=0.99) were found to be the best models for describing the Cr (VI) adsorption reactions. Conclusıon: Thermodynamic parameters such as changes in ΔG°, ΔH°, and ΔS° have been estimated, and the process was found to be spontaneous.

scholarly journals Separation of Radionuclides from a Rare Earth-Containing Solution by Zeolite Adsorption

Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 20
Author(s):  
Deniz Talan ◽  
Qingqing Huang
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Contact Time ◽  
Separation Efficiency ◽  
Ph Value ◽  
Solid Phase ◽  
Separation Performance ◽  
Solution Ph ◽  
Zeolite Sample ◽  
Alternative Sources

The increasing industrial demand for rare earths requires new or alternative sources to be found. Within this context, there have been studies validating the technical feasibility of coal and coal byproducts as alternative sources for rare earth elements. Nonetheless, radioactive materials, such as thorium and uranium, are frequently seen in the rare earths’ mineralization, and causes environmental and health concerns. Consequently, there exists an urgent need to remove these radionuclides in order to produce high purity rare earths to diversify the supply chain, as well as maintain an environmentally-favorable extraction process for the surroundings. In this study, an experimental design was generated to examine the effect of zeolite particle size, feed solution pH, zeolite amount, and contact time of solid and aqueous phases on the removal of thorium and uranium from the solution. The best separation performance was achieved using 2.50 g of 12-µm zeolite sample at a pH value of 3 with a contact time of 2 h. Under these conditions, the adsorption recovery of rare earths, thorium, and uranium into the solid phase was found to be 20.43 wt%, 99.20 wt%, and 89.60 wt%, respectively. The Freundlich adsorption isotherm was determined to be the best-fit model, and the adsorption mechanism of rare earths and thorium was identified as multilayer physisorption. Further, the separation efficiency was assessed using the response surface methodology based on the development of a statistically significant model.

Treatment of taste and odor material by oxidation and adsorption

2004 ◽  
Vol 49 (9) ◽  
pp. 289-295 ◽  
Author(s):  
S.-W. Jung ◽  
K.-H. Baek ◽  
M.-J. Yu
Keyword(s):  
Drinking Water ◽  
Raw Water ◽  
Initial Concentration ◽  
Blue Green Algae ◽  
Jar Test ◽  
Treatment Processes ◽  
Taste And Odor ◽  
Removal Efficiencies ◽  
Run Time ◽  
Lab Test

Massive blooms of blue-green algae in reservoirs produce the musty-earthy taste and odor, which are caused by compounds such as 2-MIB and geosmin. 2-MIB and geosmin are rarely removed by conventional water treatment. Their presence in the drinking water, even at low levels (ng/L), can be detected and it creates consumer complaints. So those concentrations have to be controlled as low as possible in the drinking water. The removals by oxidation (O3, Cl2, ClO2) and adsorption (PAC, filter/adsorber) were studied at laboratory and pilot plant (50 m3/d) to select suitable 2-MIB and geosmin treatment processes. The following conclusions were derived from the study. Both of the threshold odor levels for 2-MIB and geosmin appeared to be 30 ng/L as a consequence of a lab test. For any given PAC dosage in a jar-test, removal efficiencies of 2-MIB and geosmin were increased in proportion to PAC dosage and were independent of their initial concentration in raw water for the tested PAC dosages. In comparison of geosmin with 2-MIB, the adsorption efficiency of geosmin by PAC was superior to that of 2-MIB. The required PAC dosages to control below the threshold odor level were 30 mg /L for geosmin and 50 mg/L for 2-MIB at 100 ng/L of initial concentration. Removal efficiencies of odor materials by Cl2, ClO2, and O3 were very weak under the limited dosage (1.5 mg/L), however increased ozone dosage (3.8 mg O3/L) showed high removal efficiency (84.8% for 2-MIB) at contact time 6.4 minutes. According to the initial concentrations of 2-MIB and geosmin, their removal efficiencies by filter/adsorber differed from 25.7% to 88.4%. For all those, however, remaining concentrations of target materials in finished waters were maintained below 30 ng/L. The longer run-time given for the filter/adsorber, the higher the effluent concentration generated. So it is necessary that the run-time of the filter/adsorber be decreased, when 2-MIB or geosmin occurs in raw water.

scholarly journals Effectiveness of caporite to reduce concentration of iron and mangan in Ciliwung river water as raw water PDAM

2021 ◽  
Vol 11 (1) ◽  
pp. 30
Author(s):  
Nadhila Aulia Dwiputri ◽  
Mia Azizah ◽  
Nurlela Nurlela
Keyword(s):  
River Water ◽  
Government Regulation ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Quality Standard ◽  
Raw Water ◽  
Jar Test ◽  
Iron Manganese ◽  
Manganese Level ◽  
Iron And Manganese

The water of the Ciliwung river used as raw water for PDAM Depok contains iron and manganese, which levels were quite high and exceeded the quality standard. The purposes of the research are to determine the effectiveness of caporite to reduce levels of iron and manganese to reach levels that meet the standards of Government Regulation Number 82 of 2001. The sample used in this study was the water of the Ciliwung river used as a source of raw water for PDAM Depok with two different water treatment plant (WTP) locations, location 1 in Legong WTP and location 2 in Citayam WTP. Raw water was taken using a submersible water pump located at the bottom of the Ciliwung river. The analytical method used as a reference for determining iron levels was based on the FerroZine Rapid Liquid Method 1970, and for manganese levels was based on 1- (2-Pyridylazo) -2-Naphthol PAN Method 1977, both methods using the Spectrophotometric method. The results showed that iron and manganese levels were quite high, exceeding the standards of Government Regulation No.82 of 2001 with a maximum standard of iron content is 0.3 mg/L, and a maximum standard of manganese level is 0.1 mg/L. After adding a certain dose of chlorine to Ciliwung river water in the Legong and Citayam WTPs, it was found that chlorine effectively reduced Fe and Mn levels because it was able to reduce levels up to 80% and meet the quality standards.Keywords: Caporite, Iron, Manganese, Ciliwung River, RegulationABSTRAKEfektivitas kaporit untuk menurunkan kadar besi dan mangan dalam air sungai Ciliwung sebagai air baku PDAMAir sungai Ciliwung yang digunakan sebagai air baku PDAM Depok terdapat zat besi dan mangan dengan kadarnya cukup tinggi serta melebihi ambang baku mutu. Tujuan penelitian ini untuk mengetahui efektivitas kaporit dalam menurunkan kadar besi dan mangan sehingga memenuhi standar baku mutu Peraturan Pemerintah Nomor 82 Tahun 2001 untuk kelas 1. Sampel air yang digunakan dalam penelitian ini diambil dari 2 titik lokasi Instalasi Pengolahan Air (IPA) yang berbeda, yaitu  dari IPA Legong dan  IPA Citayam. Sampel air baku diambil dengan menggunakan pompa air submersible (pompa celup) yang berada di dasar sungai Ciliwung. Penelitian dilakukan dengan eksperimen jar test di laboratorium. Metode analisis untuk menentukan kadar besi  mengacu pada FerroZine Rapid Liquid Method tahun 1970 dan mangan berdasarkan 1-(2-Pyridylazo)-2-Napthol PAN Method tahun 1977 dengan menggunakan metode Spektrofotometri. Hasil penelitian menunjukan kadar besi dan mangan yang cukup tinggi hingga melebihi standar yang telah ditetapkan dalam PP No.82 Tahun 2001 dengan kadar Fe maksimal 0,3 mg/L dan kadar Mn maksimal 0,1 mg/L. Setelah dilakukan penambahan bahan kimia kaporit ke dalam sampel air sungai Ciliwung  dari  IPA Legong dan Citayam, dengan dosis 10 mg/L untuk penurunan Fe dan 30 mg/L untuk penurunan Mn dapat efektif menurunkan konsentrasi Fe dan Mn  hingga 80%, dan memenuhi  standar baku mutu yang digunakan.Kata Kunci: Kaporit, Besi, Mangan, Sungai Ciliwung, Baku Mutu

scholarly journals OPTIMIZATION OF THE DRINKING WATER TREATMENT PROCESS OF A SUGAR PLANT STATION IN COTE DIVOIRE

2021 ◽  
Vol 9 (01) ◽  
pp. 512-524
Author(s):  
Konan Lopez Kouame ◽  
◽  
Nogbou Emmanuel Assidjo ◽  
Andre Kone Ariban ◽  
◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Treatment Process ◽  
Polynomial Regression ◽  
Drinking Water Treatment ◽  
Optimal Dose ◽  
Raw Water ◽  
Water Treatment Process ◽  
Jar Test ◽  
Coagulation And Flocculation

This article presents an optimization of the drinking water treatment process at the SUCRIVOIRE treatment station. The objective is to optimize the coagulation and flocculation process (fundamental process of the treatment of said plant)by determining the optimal dosages of the products injected and then proposes a program for calculating the optimal dose of coagulant in order to automatically determine the optimal dose of the latter according to the raw water quality. This contribution has the advantage of saving the user from any calculations the latter simply enters the characteristics of the raw effluent using the physical interface of the program in order to obtain the optimum corresponding coagulant concentration. For the determination of the optimal coagulant doses, we performed Jar-Test flocculation tests in the laboratory over a period of three months. The results made it possible to set up a polynomial regression model of the optimal dose of alumina sulfate as a function of the raw water parameters. A program for calculating the optimal dose of coagulant was carried out on Visual Basic. The optimal doses of coagulant obtained vary from 25, 35, 40 and 45 mg/l depending on the characteristics of the raw effluent. The model obtained is: . Finally, verification tests were carried out using this model on the process. The results obtained meet the WHO drinkability standards for all parameters for a settling time of two hours.

Amidoxime Functionalized Mesoporous SBA-15 with Various Mesostructures for Highly Efficient Concentration of U(VI)

NANO ◽  
2019 ◽  
Vol 14 (02) ◽  
pp. 1950027
Author(s):  
Ziyan Yang ◽  
Xiaoli Yang ◽  
Rui Hu ◽  
Junfeng Wu
Keyword(s):  
Surface Chemistry ◽  
Aqueous Solutions ◽  
Contact Time ◽  
High Selectivity ◽  
Ph Value ◽  
Sorption Kinetics ◽  
Initial Concentration ◽  
Geochemical Conditions ◽  
Pore Length ◽  
Ordered Mesoporous

Many current sorbents are limited for U(VI) concentration from aqueous solutions due to their inappropriate structures and surface chemistry. Herein, we report the rapid sorption of U(VI) with high capacities and selectivity by amidoxime modified ordered mesoporous SBA-15 with two typical morphologies (i.e., rods and plates) via a post-grafting method. Variables of the geochemical conditions (contact time, pH value, initial concentration, temperature and coexisting metal ions) are investigated. The results show that the mesostructures including morphologies and pore length of SBA-15 perform the dominant function for the fast sorption kinetics (10[Formula: see text]min for plates, 20[Formula: see text]min for rods), while the modified amidoxime groups make the excellent U(VI) sorption capacities (646.2[Formula: see text]mg[Formula: see text][Formula: see text][Formula: see text]g[Formula: see text] for plates, 499.8[Formula: see text]mg[Formula: see text][Formula: see text][Formula: see text]g[Formula: see text] for rods at pH 5.0 and [Formula: see text] 298.15[Formula: see text]K) and high selectivity possible. U(VI) adsorbed amidoxime-functionalized SBA can also be effectively regenerated by HCl solutions and reused well after six cycles.

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