scholarly journals Disinfection of municipal wastewater by TiO2 photocatalysis with UV-A, visible and solar irradiation and BDD electrolysis

2013 ◽  
Vol 11 (3) ◽  
pp. 357-363
Keyword(s):  
Municipal Wastewater ◽  
Electrochemical Process ◽  
Solar Irradiation ◽  
Initial Population ◽  
Order Kinetic ◽  
Boron Doped Diamond ◽  
Experimental Conditions ◽  
Tio2 Photocatalysis ◽  
Treated Effluent ◽  
Artificial Uv

The efficiency of TiO2 photocatalysis induced by ultraviolet and visible irradiation and salt-free electrolysis over boron-doped diamond electrodes to inactivate total (TC) and fecal (FC) coliforms in secondary treated municipal wastewater was evaluated. Photocatalytic experiments were conducted with two types of titania (Degussa P25 and sulfur-doped catalyst) at loadings in the range 0.1-0.5 g l-1 and three types of irradiation, i.e. artificial UV-A, artificial visible and solar. Electrolysis was conducted in a flow-through cell at anodic current densities of 14.3 and 28.6 mA cm-2 without the addition of auxiliary chemicals. Inactivation followed a first-order kinetic expression with regard to bacteria population and the rate was dependent of the experimental conditions in question. In general, electrochemical disinfection was up to about two orders of magnitude faster than photocatalysis; for instance, TC population decreased to less than 5% of the initial population after 9 and 4 min at 14.3 mA cm-2 and 28.6 mA cm-2 respectively. Similar efficiencies with TiO2 photocatalysis would require at least 30 min of contact time. Interestingly, energy consumption for the electrochemical process was computed to about 0.5 kWh per m3 of treated effluent, well below the respective value for photocatalysis.

scholarly journals PROTEOMIC SIGNATURES OF MICROBIAL ADAPTATION TO THE HIGHEST UV -IRRADIATION ON EARTH: LESSONS FROM A SOIL ACTINOBACTERIUM

2021 ◽  
Author(s):  
Federico Zannier ◽  
Luciano R. Portero ◽  
Thierry Douki ◽  
Wolfgang Gärtner ◽  
Virginia Helena Albarracin
Keyword(s):  
Genomic Analysis ◽  
Solar Irradiation ◽  
Experimental Conditions ◽  
Microbial Adaptation ◽  
Molecular Events ◽  
Total Solar Irradiation ◽  
Microbial Strains ◽  
Artificial Uv ◽  
Antioxidant Mechanisms

In the Puna region, the total solar irradiation and the UV incidence is the highest on Earth, thus, restraining the physiology of individual microorganisms and the composition of microbial communities. UV-resistance of microbial strains thriving in High-Altitude Andean Lakes was demonstrated and their mechanisms were partially characterized by genomic analysis, biochemical and physiological assays. In this work, we present the molecular events involved in the adaptive response of the model HAAL extremophilic actinobacterium Nesterenkonia sp. Act20 under artificial UV-B radiation, herein called as UV-resistome. Proteomic profiles of cultures exposed to different UV-experimental conditions showed that the leading systems for adaptation to the UV-challenge in-vitro are DNA repair and antioxidant mechanisms.

Efficiency and toxicity: comparison between the Fenton and electrochemical processes

2016 ◽  
Vol 74 (5) ◽  
pp. 1143-1154 ◽  
Author(s):  
Marcela Gomes Tavares ◽  
Danilo Henrique da Silva Santos ◽  
Sheyla Jaqueline Albuquerque Torres ◽  
Wagner Roberto Oliveira Pimentel ◽  
Josealdo Tonholo ◽  
...  
Keyword(s):  
Fenton Reaction ◽  
High Current Density ◽  
Electrochemical Treatment ◽  
Electrochemical Process ◽  
High Current ◽  
Experimental Conditions ◽  
Electrochemical Processes ◽  
Treated Effluent ◽  
Dye Oxidation ◽  
Germination And Growth

This study aimed to determine the best method to treat a textile effluent containing the dye basic blue 99 (BB). Treatments by the electrochemical and the Fenton processes were compared by means of a 23 experimental design, and the interaction of experimental conditions for BB oxidation were determined. The electrochemical treatment gave better results in the presence of NaCl as electrolyte and high current density (30 mA cm−2); the Fenton reaction provided better results at H2O2 and Fe2+ concentrations of 10 mg L−1 and 0.5 mmol L−1, respectively. Electrochemical treatment was 23 times faster than the Fenton reaction because formation of chlorinated species during electrooxidation significantly contributed to dye oxidation. Although the electrochemical process was more efficient, the resulting treated effluent was more toxic to Lactuca sativa germination and growth, which indicated some biotoxicity. Results demonstrated that both processes efficiently remediated effluents containing the dye BB, but they need to be combined with other processes to ensure complete adequacy of the effluent for disposal.

Modelling of bacterial removal in wastewater storage reservoir for irrigation purposes: a case study in Sicily, Italy

2003 ◽  
Vol 3 (4) ◽  
pp. 169-175 ◽  
Author(s):  
S. Barbagallo ◽  
F. Brissaud ◽  
G.L. Cirelli ◽  
S. Consoli ◽  
P. Xu
Keyword(s):  
Municipal Wastewater ◽  
High Reliability ◽  
Low Cost ◽  
Public Awareness ◽  
Storage System ◽  
Wastewater Reuse ◽  
Order Kinetic ◽  
Aquifer Recharge ◽  
Mediterranean Countries ◽  
Storage Reservoirs

In arid and semiarid regions the reclamation and reuse of municipal wastewater can play a strategic role in alleviating water resources shortages. Public awareness is growing about the need to recycle and reuse water for increasing supply availability. Many wastewater reuse projects have been put in operation in European and Mediterranean countries adopting extensive treatment systems such as aquifer recharge, lagooning, constructed wetlands, and storage reservoirs, mainly for landscape and agricultural irrigation. In agricultural reuse systems, there is an increasing interest in extensive technologies because of their high reliability, and easy and low cost operation and maintenance. Wastewater storage reservoirs have become the option selected in many countries because of the advantages they present in comparison with other treatment alternatives, namely the coupling of two purposes, stabilization and seasonal regulation. This paper describes an example of a wastewater storage system, built in Caltagirone (Sicily, Italy). The storage results in a tertiary treatment of a continuous inlet flow of activated sludge effluents. The prediction of the microbiological water quality has been evaluated by means of a non-steady-state first-order kinetic model. Single and multiple regressions were applied to determine the main variables that most significantly affected die-off coefficients. The proposed model has been calibrated using the results of a field monitoring carried out during a period from March to October 2000.

Activated sludge plant facing grape harvest period – a case study

1996 ◽  
Vol 34 (11) ◽  
pp. 25-32 ◽  
Author(s):  
P. Chudoba ◽  
R. Pujol
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Organic Pollution ◽  
Worst Case ◽  
Wine Production ◽  
Original Solution ◽  
Treated Effluent ◽  
Nominal Capacity ◽  
Sludge Settleability

Most of municipal activated sludge plants located in wine production regions receive winery wastewaters during the grape harvest period which lasts usually only a few weeks. A drastic increase in organic pollution (COD, BOD) during this period generates a temporary overloading, resulting very often in biological problems such as decreased sludge settleability, sludge floc disintegration, increased SS concentration in treated effluent and in the worst case a complete plant failure. In order to work satisfactorily even during those temporary overloading periods, the plant has to be oversized. This strategy is rather costly, because such a plant has to run below its nominal capacity during a major part of the year. An original solution has been proposed and successfully tested at a municipal wastewater treatment plant in Eguisheim, France. The proposed technique is based on the addition of a mineral material with a low particle size, whose presence positively influences the physical behaviour of the sludge and will allow the nominal capacity of the plant to be surpassed without any important modification. The modification of the sludge structure around the added powdered material improved significantly the sludge settleability (DSVI< 160 ml/g) and enabled the plant to treat organic pollution several times higher than the nominal level.

Municipal wastewater treatment with pond–constructed wetland system: a case study

2005 ◽  
Vol 51 (12) ◽  
pp. 325-329 ◽  
Author(s):  
X. Wang ◽  
X. Bai ◽  
J. Qiu ◽  
B. Wang
Keyword(s):  
Constructed Wetland ◽  
Municipal Wastewater ◽  
Municipal Wastewater Treatment ◽  
Oxidation Pond ◽  
System A ◽  
Treated Effluent ◽  
Wetland System ◽  
Oxidation Ponds ◽  
Better Than

The performance of a pond–constructed wetland system in the treatment of municipal wastewater in Kiaochow city was studied; and comparison with oxidation ponds system was conducted. In the post-constructed wetland, the removal of COD, TN and TP is 24%, 58.5% and 24.8% respectively. The treated effluent from the constructed wetland can meet the Chinese National Agricultural and Irrigation Standard. The comparison between pond–constructed wetland system and oxidation pond system shows that total nitrogen removal in a constructed wetland is better than that in an oxidation pond and the TP removal is inferior. A possible reason is the low dissolved oxygen concentration in the wetland. Constructed wetlands can restrain the growth of algae effectively, and can produce obvious ecological and economical benefits.

scholarly journals Low-coherence photonic method of electrochemical processes monitoring

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Monika Kosowska ◽  
Paweł Jakóbczyk ◽  
Michał Rycewicz ◽  
Alex Vitkin ◽  
Małgorzata Szczerska
Keyword(s):  
Electrochemical Process ◽  
Electrochemical Measurements ◽  
Boron Doped Diamond ◽  
Silica Substrate ◽  
Low Coherence ◽  
Optical Responses ◽  
Boron Doped ◽  
Fabry Perot ◽  
Hybrid Characterization

AbstractWe present an advanced multimodality characterization platform for simultaneous optical and electrochemical measurements of ferrocyanides. Specifically, we combined a fiber-optic Fabry–Perot interferometer with a three-electrode electrochemical setup to demonstrate a proof-of-principle of this hybrid characterization approach, and obtained feasibility data in its monitoring of electrochemical reactions in a boron-doped diamond film deposited on a silica substrate. The film plays the dual role of being the working electrode in the electrochemical reaction, as well as affording the reflectivity to enable the optical interferometry measurements. Optical responses during the redox reactions of the electrochemical process are presented. This work proves that simultaneous opto-electrochemical measurements of liquids are possible.

Phosphorus removal from aqueous solution using a novel granular material developed from building waste

2017 ◽  
Vol 75 (6) ◽  
pp. 1500-1511 ◽  
Author(s):  
Shengjiong Yang ◽  
Pengkang Jin ◽  
Xiaochang C. Wang ◽  
Qionghua Zhang ◽  
Xiaotian Chen
Keyword(s):  
Granular Material ◽  
Chemical Precipitation ◽  
Phosphate Removal ◽  
Precipitation Process ◽  
Order Kinetic ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Removal Capacity ◽  
Order Kinetic Model ◽  
Pseudo Second Order

In this study, a granular material (GM) developed from building waste was used for phosphate removal from phosphorus-containing wastewater. Batch experiments were executed to investigate the phosphate removal capacity of this material. The mechanism of removal proved to be a chemical precipitation process. The characteristics of the material and resulting precipitates, the kinetics of the precipitation and Ca2+ liberation processes, and the effects of dosage and pH were investigated. The phosphate precipitation and Ca2+ liberation processes were both well described by a pseudo-second-order kinetic model. A maximum precipitation capacity of 0.51 ± 0.06 mg g−1 and a liberation capacity of 6.79 ± 0.77 mg g−1 were measured under the experimental conditions. The processes reached equilibrium in 60 min. The initial solution pH strongly affected phosphate removal under extreme conditions (pH <4 and pH >10). The precipitates comprised hydroxyapatite and brushite. This novel GM can be considered a promising material for phosphate removal from wastewater.

Preparation of cationic waste paper and its application in poisonous dye removal

2013 ◽  
Vol 67 (11) ◽  
pp. 2560-2567 ◽  
Author(s):  
Fan Yang ◽  
Xiaojie Song ◽  
Lifeng Yan
Keyword(s):  
Low Cost ◽  
Aqueous Suspension ◽  
Order Kinetic ◽  
Acid Orange 7 ◽  
Anionic Dyes ◽  
Experimental Conditions ◽  
Adsorption Models ◽  
Acid Orange ◽  
Initial Ph ◽  
Pseudo Second Order

Cationic paper was prepared by reaction of paper with 2,3-epoxypropyltrimethylammonium chloride in aqueous suspension, and tested as low-cost adsorbent for wastewater treatment. The experimental results revealed that anionic dyes (Acid Orange 7, Acid Red 18, and Acid Blue 92) were adsorbed on the cationic paper nicely. The maximum amount of dye Acid Orange 7 adsorbed on cationic paper was 337.2 mg/g in experimental conditions. The effects of initial dye concentration, temperature, and initial pH of dye solution on adsorption capacity of cationic paper were studied. The pseudo-first-order and pseudo-second-order kinetic models were applied to describe the kinetic data. The Freundlich and Langmuir adsorption models were used to describe adsorption equilibrium. The thermodynamic data indicated that the adsorption process of dye on cationic paper occurred spontaneously.

Removal of colour from a kraft pulp and paper mill effluent in Kenya using a combination of electrochemical method and phosphate rock

2007 ◽  
Vol 55 (6) ◽  
pp. 15-22 ◽  
Author(s):  
L. Etiégni ◽  
O.D. Oricho ◽  
K. Ofosu-Asiedu ◽  
K.A. Senelwa ◽  
K.G. Surtan ◽  
...  
Keyword(s):  
Electrochemical Method ◽  
Phosphate Rock ◽  
Complete Removal ◽  
Paper Mill ◽  
Wood Ash ◽  
Electrochemical Process ◽  
Pulp And Paper Mill ◽  
Allowable Limit ◽  
Paper Mill Effluent ◽  
Treated Effluent

A study was undertaken to remove colour from a kraft mill's treated effluent in Kenya and determine the suitability of phosphate rock to replace wood ash during the electrochemical process. The electrochemical method alone, electrochemical combined with alum (ELCAL), wood ash leachate (ELCAS) and phosphate rock (ELPHOS) solutions at a rate of 165 to 1,000 g/m3 were tested. Effluent characteristics were determined after complete removal of colour. Same reduction rates of TS (85%) and TSS (89%) were recorded by ELCAS and ELPHOS. However, ELPHOS removed more COD (86 to 91%) and more BOD (85 to 92%) than ELCAS. Furthermore, the pH of ELPHOS treated solution was 9.3, within the Kenya Local Government's allowable limit. Power reduction with ELCAS and ELPHOS varied between 53 to 73% and 49 to 69% respectively but the difference was not statistically significant. Overnight aeration further improved the quality of ELCAS and ELPHOS treated effluent, reducing BOD and COD values to 0 mg/l. ELPHOS cost ($0.29/m3) was nevertheless three times higher than that of ELCAS ($0.10/m3), mainly because of free wood ash. ELPHOS did not also increase effluent phosphorus. It was therefore recommended that various ways be explored in making ELPHOS more economical to replace ELCAS.

scholarly journals A Comparative Electrochemical-Ozone Treatment for Removal of Phenolphthalein

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
V. M. García-Orozco ◽  
C. E. Barrera-Díaz ◽  
G. Roa-Morales ◽  
Ivonne Linares-Hernández
Keyword(s):  
Electrochemical Treatment ◽  
Electrochemical Process ◽  
Ozone Treatment ◽  
Acidic Ph ◽  
Alkaline Ph ◽  
Diamond Electrodes ◽  
Boron Doped Diamond ◽  
Boron Doped ◽  
Electrochemical Processes ◽  
Density Values

The degradation of aqueous solutions containing phenolphthalein was carried out using ozone and electrochemical processes; the two different treatments were performed for 60 min at pH 3, pH 7, and pH 9. The electrochemical oxidation using boron-doped diamond electrodes processes was carried out using three current density values: 3.11 mA·cm−2, 6.22 mA·cm−2, and 9.33 mA·cm−2, whereas the ozone dose was constantly supplied at 5±0.5 mgL−1. An optimal degradation condition for the ozonation treatment is at alkaline pH, while the electrochemical treatment works better at acidic pH. The electrochemical process is twice better compared with ozonation.

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