Comparative study of degradation of 4-chlorophenol by ultraviolet irradiation/sodium hypochlorite and ultraviolet irradiation/ozonation

2009 ◽  
Vol 9 (5) ◽  
pp. 601-609 ◽  
Author(s):  
J. Fu ◽  
J. Huang ◽  
Z. Liu ◽  
Q. F. Zeng ◽  
S. Q. An ◽  
...  
Keyword(s):  
Sodium Hypochlorite ◽  
Ultraviolet Irradiation ◽  
Pilot Scale ◽  
Economic Advantage ◽  
Photochemical Oxidation ◽  
Small Scale ◽  
Final Solution ◽  
Ph Values ◽  
Organic Halogens ◽  
Adsorbable Organic Halogens

The photochemical oxidation of 4-chlorophenol solutions by ultraviolet irradiation/sodium hypochlorite (UV/NaClO) and ultraviolet irradiation/ozonation (UV/O3) respectively was studied in a pilot scale photochemical reactor. The degradation efficiency of UV/NaClO was lower than that of UV/O3. The final UV absorption removals of the two processes were approximately 80% and approximately 90% respectively. During the two processes, dihydroxylated chlorophenols were the main intermediates. And pH values decreased with the oxidation being carried on. However, the UV/NaClO process was incomplete and some adsorbable organic halogens, such as ethyl 2-chloroacetate, 3,4-dichlorobut-3-en-2-one, ethyl 2,2-dichloroacetate, 2-chloro-1,1-diethoxyethane, ethyl 2,2,2-trichloroacetate and 2,4,6-trichlorophenol, still existed in the final solution. The costs of the two processes were also estimated. On a small scale, UV/NaClO process had significant economic advantage.

Adsorbable Organic Halogens Generation and Reduction During Degradation of Phenol by UV Radiation/Sodium Hypochlorite

2009 ◽  
Vol 81 (2) ◽  
pp. 178-183 ◽  
Author(s):  
Qing-fu Zeng ◽  
Jie Fu ◽  
Yin-tao Shi ◽  
Dong-sheng Xia ◽  
Hai-liang Zhu
Keyword(s):  
Uv Radiation ◽  
Sodium Hypochlorite ◽  
Organic Halogens ◽  
Adsorbable Organic Halogens

CHEMICAL PULPING. Oxidative degradation of AOX in softwood-based kraft mill effluents from E C F bleachin g

2012 ◽  
Vol 27 (4) ◽  
pp. 707-713 ◽  
Author(s):  
Jukka Pekka lsoaho ◽  
Suvi Tarkkanen ◽  
Raimo Alen ◽  
Juha Fiskari
Keyword(s):  
Reaction Time ◽  
Oxidative Degradation ◽  
Cost Effective ◽  
Process Conditions ◽  
Main Process ◽  
Chemical Pulping ◽  
Kraft Mill ◽  
Organic Halogens ◽  
Aox Removal ◽  
Adsorbable Organic Halogens

Abstract Softwood-based kraft mill bleaching effluents from the initial bleaching stages D0 and E1 (the bleaching sequence being D0E 1D 1 E2D2) were treated by the oxidative Fenton method (H20rFeS04) to decompose organic pollutants contammg adsorbable organic halogens (AOX). Experiments designed using the Taguchi method were applied to predict the process conditions that would result in a cost-effective and adequate removal of AOX. In addition to the composition and concentration of the reagents (H202 and Fe2+), the main process parameters selected were temperature and reaction time, while pH was adj usted to an approximate value of 4 (the volumetric ratio of the mixed effluents D0:E 1 was 3 :2). The results indicated that an AOX removal of about 70% for this mixture ( corresponding to about 50% for the mill) was achieved when the eftluent samples were treated for 60 min at 70°C with H202 and Fe2+ at a concentration of 1 600 mg/1 and 28 mg/1, respectively.

scholarly journals Growth of Haematococcus pluvialis on a Small-Scale Angled Porous Substrate Photobioreactor for Green Stage Biomass

2021 ◽  
Vol 11 (4) ◽  
pp. 1788
Author(s):  
Thanh-Tri Do ◽  
Binh-Nguyen Ong ◽  
Tuan-Loc Le ◽  
Thanh-Cong Nguyen ◽  
Bich-Huy Tran-Thi ◽  
...  
Keyword(s):  
Light Intensity ◽  
Algal Biomass ◽  
Haematococcus Pluvialis ◽  
Biomass Productivity ◽  
Pilot Scale ◽  
Small Scale ◽  
Porous Substrate ◽  
Low Light ◽  
Green Algal ◽  
Green Stage

In the production of astaxanthin from Haematococcus pluvialis, the process of growing algal biomass in the vegetative green stage is an indispensable step in both suspended and immobilized cultivations. The green algal biomass is usually cultured in a suspension under a low light intensity. However, for astaxanthin accumulation, the microalgae need to be centrifuged and transferred to a new medium or culture system, a significant difficulty when upscaling astaxanthin production. In this research, a small-scale angled twin-layer porous substrate photobioreactor (TL-PSBR) was used to cultivate green stage biomass of H. pluvialis. Under low light intensities of 20–80 µmol photons m−2·s−1, algae in the biofilm consisted exclusively of non-motile vegetative cells (green palmella cells) after ten days of culturing. The optimal initial biomass density was 6.5 g·m−2, and the dry biomass productivity at a light intensity of 80 µmol photons m−2·s−1 was 6.5 g·m−2·d−1. The green stage biomass of H. pluvialis created in this small-scale angled TL-PSBR can be easily harvested and directly used as the source of material for the inoculation of a pilot-scale TL-PSBR for the production of astaxanthin.

scholarly journals Primary Productivity of Phytoplankton in Loch Leven, Kinross

1974 ◽  
Vol 74 ◽  
pp. 157-181 ◽  
Author(s):  
Margaret E. Bindloss
Keyword(s):  
Photosynthetic Capacity ◽  
Photochemical Oxidation ◽  
Light Extinction ◽  
Poor Correlation ◽  
Dark Bottle ◽  
Gross Photosynthesis ◽  
Ph Values ◽  
Photosynthetic Productivity ◽  
Loch Leven ◽  
Crop Density

SynopsisPhotosynthetic productivity of phytoplankton in Loch Leven was studied over a 4-year period (1968–71), using the oxygen light and dark bottle technique. Marked seasonal changes in hourly and daily rates of gross photosynthetic productivity are described within the range 0·02 to 1·59 g O2/m2.h and 0·4 to 21·0 g O2/m2.day respectively. Hourly rates are shown to be relatively insensitive to variations in surface light intensity, whereas daily rates are influenced to a considerable extent by the duration of incident radiation (daylength).The phytoplankton itself exerts a dominant influence on underwater light penetration, accounting for ca 75 per cent of light extinction at highest crop densities. This self-shading effect contributes to the poor correlation observed between crop density and areal gross productivity. The chlorophyll a content per unit area in the euphotic zone often approached its estimated theoretical limit of 430 mg/m2.In general, increase in photosynthetic capacity (per unit content of chlorophyll a) accompanied increase in water temperature. During certain periods an inverse relationship between photosynthetic capacity and population density was evident. Reduction in photosynthetic capacity is attributed, in part, to the high pH values (> 9·5) with concomitant CO2-depIetion associated with dense phytoplankton crops.Estimates of net photosynthetic productivity were frequently zero or negative, even over periods when algal populations were increasing and dissolved oxygen and pH values were above their respective air-equilibrium values. Underestimation of gross photosynthesis due to photochemical oxidation, photorespiration or the use of stationary bottles could not account for this apparent anomaly. The most probable sources of error in the estimates of net photosynthetic productivity are discussed.

scholarly journals Numerical optimisation of a small-scale wind turbine through the use of surrogate modelling

2017 ◽  
Vol 28 (3) ◽  
pp. 79 ◽  
Author(s):  
Gareth Erfort ◽  
Theodor Willem Von Backström ◽  
Gerhard Venter
Keyword(s):  
Genetic Algorithm ◽  
Wind Turbine ◽  
Surrogate Model ◽  
Turbine Blades ◽  
Small Scale ◽  
Final Solution ◽  
B Splines ◽  
Wind Speeds ◽  
Wide Range ◽  
Numerical Optimisation

Wind conditions in South Africa are suitable for small-scale wind turbines, with wind speeds below 7 m.s−1. This investigation is about a methodology to optimise a full wind turbine using a surrogate model. A previously optimised turbine was further optimised over a range of wind speeds in terms of a new parameterisation methodology for the aerodynamic profile of the turbine blades, using non-uniform rational B-splines to encompass a wide range of possible shapes. The optimisation process used a genetic algorithm to evaluate an input vector of 61 variables, which fully described the geometry, wind conditions and rotational speed of the turbine. The optimal performance was assessed according to a weighted coefficient of power, which rated the turbine blade’s ability to extract power from the available wind stream. This methodology was validated using XFOIL to assess the final solution. The results showed that the surrogate model was successful in providing an optimised solution and, with further refinement, could increase the coefficient of power obtained.

Coagulation-Direct Filtration of Soft, Low Alkalinity Humic Waters

1999 ◽  
Vol 40 (9) ◽  
pp. 55-62 ◽  
Author(s):  
Bjørnar Eikebrokk
Keyword(s):  
Natural Organic Matter ◽  
Pilot Scale ◽  
Quality Parameters ◽  
Efficient Removal ◽  
Direct Filtration ◽  
Ph Values ◽  
Optimum Ph ◽  
Calcium Sources ◽  
Ph Conditions ◽  
Removal Efficiencies

Optimisation of coagulation-direct filtration processes with respect to efficient removal of humic substances, i.e. natural organic matter (NOM) has gained a lot of focus in many countries over the last years. This paper presents experimental results from pilot scale research studies aimed at optimising the coagulation-direct filtration process applied to soft and humic raw waters with low turbidity and alkalinity levels. Comprehensive tests of 3 types of raw waters with different NOM content, 5 types of coagulants, and 3 calcium sources for the purpose of corrosion control have been conducted. Removal efficiencies with respect to relevant water quality parameters are presented, with typical relationships between raw water NOM content, coagulant dose requirements and pH. Generally, when applying metal-based coagulants, residual metal concentration was the critical parameter regarding minimum coagulant dose requirements. Typical NOM removal efficiencies were in the range of 75-90% and 40-70% with respect to colour and organic carbon, respectively. Optimum pH conditions for the removal of NOM and/or residual metals do not always coincide with that of turbidity. The experiments also showed that poly-aluminium and ferric chlorides might have some benefits over alum in terms of dose requirements and range of optimum pH values, and that chitosan may be used for colour removal with good results.

Pig Wastewater Treatment in Water Hyacinth Ponds

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2381-2384 ◽  
Author(s):  
C. Polprasert ◽  
S. Kessomboon ◽  
W. Kanjanaprapin
Keyword(s):  
Wastewater Treatment ◽  
Water Hyacinth ◽  
Loading Rate ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Cod Removal ◽  
Organic Loading Rate ◽  
Small Scale ◽  
N Removal ◽  
In Series

Small-scale and pilot-scale experiments were conducted on pig wastewater treatment in water hyacinth (Eichhornia crassipesl ponds. The main objectives were to evaluate the treatment performance of the water hyacinth ponds and to determine suitable operating conditions. From the experimental results obtained, the optimum organic loading rate was found to be 200 kg COD/(ha.d), while the hydraulic retention times were proposed to be 10-20 days. The % COD removal in the small-scale water hyacinth ponds were 74-93, while for the pilot-scale ponds the % COD removal were 52-72 because of fluctuations in the influent wastewater characteristics and occasional insect attacks on the water hyacinth leaves and stems. Similar results were obtained for N removal. Although the water hyacinth ponds were found to be feasible for pig wastewater treatment, at least one polishing pond in series should be provided to polish the water hyacinth pond effluents before discharging into the environment.

A Scaling-up Approach from Experimental Tunnel to Spray Dryer

2010 ◽  
Vol 6 (1) ◽  
Author(s):  
Xuan-You Li ◽  
Ireneusz Zbicinski ◽  
Jing Wu
Keyword(s):  
Spray Drying ◽  
Scale Up ◽  
Scaling Up ◽  
Pilot Scale ◽  
Drying Kinetics ◽  
Water Evaporation ◽  
Small Scale ◽  
Spray Dryer ◽  
Cfd Modelling ◽  
Initial Water

A scaling-up approach from drying of a thin layer wet material in a experimental tunnel to a pilot scale spray drying was developed through determining drying kinetics of quick evaporation process. Maltodextin was selected as solid material in solution to be dried. Critical moisture contents as a function of initial water evaporation rate (drying rate) shows that there is the same variation between the small scale test tunnel and the pilot scale spray dryer. Result of CFD modelling demonstrates that drying kinetics obtained from the small-scale tunnel could be properly applied to scale-up the spray drying process.

Inactivation ofBacillusspores in decontamination wash down wastewater using chlorine bleach solution

2014 ◽  
Vol 41 (1) ◽  
pp. 40-47
Author(s):  
Nur Muhammad ◽  
Vicente J. Gallardo ◽  
Donald A. Schupp ◽  
E. Radha Krishnan ◽  
K. Scott Minamyer ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Sodium Hypochlorite ◽  
Room Temperature ◽  
Pilot Scale ◽  
Bacillus Atrophaeus ◽  
National Response ◽  
Bacillus Anthracis Spores ◽  
Response Team ◽  
Bacillus Spores ◽  
Chlorine Bleach

Bacillus anthracis spores are highly resistant to disinfection. The effectiveness of sodium hypochlorite (bleach) solution for the inactivation of Bacillus atrophaeus subspecies globigii spores (a surrogate for Bacillus anthracis) in wash down wastewater was evaluated by a series of bench-scale and pilot-scale experiments. The wastewater was generated from a simulated decontamination of interior laboratory surfaces and personal protective equipment. A concentration of approximately 5% (v/v) bleach solution was adequate for a ≥7 log10inactivation of Bacillus spores spiked in wastewater after 10 min of contact time at room temperature. This sodium hypochlorite dose is less than the U.S. National Response Team-recommended formulation of 10% (v/v) bleach solution with 10% (v/v) vinegar. For the wash down waters evaluated, the addition of vinegar was not required. Inactivation of Bacillus spores was faster when a detergent was added to the wash down waters tested.

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