INFLUENCE OF OXIDATION-REDUCTION REDUCTANTS ON SALMONELLA TYPHIMURIUM GROWTH RATES AFTER INITIAL pH ADJUSTMENT AND ZINC COMPOUND ADDITION

2004 ◽  
Vol 12 (3) ◽  
pp. 185-197 ◽  
Author(s):  
S.Y. PARK ◽  
C.L. WOODWARD ◽  
S.G. BIRKHOLD ◽  
L.F. KUBENA ◽  
D.J. NISBET ◽  
...  
Keyword(s):  
Salmonella Typhimurium ◽  
Growth Rates ◽  
Ph Adjustment ◽  
Oxidation Reduction ◽  
Initial Ph ◽  
Zinc Compound

scholarly journals Silica Removal from a Paper Mill Effluent by Adsorption on Pseudoboehmite and γ-Al2O3

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2031
Author(s):  
Ruben Miranda ◽  
Isabel Latour ◽  
Angeles Blanco
Keyword(s):  
Paper Mill ◽  
Ph Adjustment ◽  
Paper Mill Effluent ◽  
Kinetics Studies ◽  
Silica Removal ◽  
Industrial Water Use ◽  
Optimum Ph ◽  
Initial Ph ◽  
Equilibrium And Kinetics ◽  
Kinetics Of

Effluent reuse is a common practice for sustainable industrial water use. Salt removal is usually carried out by a combination of membrane processes with a final reverse osmosis (RO). However, the presence of silica limits the RO efficiency due to its high scaling potential and the difficulty of cleaning the fouled membranes. Silica adsorption has many advantages compared to coagulation and precipitation at high pHs: pH adjustment is not necessary, the conductivity of treated waters is not increased, and there is no sludge generation. Therefore, this study investigates the feasibility of using pseudoboehmite and its calcination product (γ-Al2O3) for silica adsorption from a paper mill effluent. The effect of sorbent dosage, pH, and temperature, including both equilibrium and kinetics studies, were studied. γ-Al2O3 was clearly more efficient than pseudoboehmite, with optimal dosages around 2.5–5 g/L vs. 7.5–15 g/L. The optimum pH is around 8.5–10, which fits well with the initial pH of the effluent. The kinetics of silica adsorption is fast, especially at high dosages and temperatures: 80–90% of the removable silica is removed in 1 h. At these conditions, silica removal is around 75–85% (<50 mg/L SiO2 in the treated water).

The pretreatment of acrylonitrile and styrene with the ozonation process

1997 ◽  
Vol 36 (2-3) ◽  
pp. 263-270 ◽  
Author(s):  
Cheng-Nan Chang ◽  
Jih-Gaw Lin ◽  
Allen C. Chao ◽  
Bo-Chuan Cho ◽  
Ruey-Fang Yu
Keyword(s):  
Organic Nitrogen ◽  
Ph Value ◽  
Raw Materials ◽  
Removal Rate ◽  
Acrylonitrile Butadiene Styrene ◽  
Ozone Treatment ◽  
Oxidation Reduction ◽  
Initial Ph ◽  
Cod Removal Rate ◽  
Ozonation Process

Acrylonitrile and styrene are used as the raw materials for manufacturing acrylic fiber, thus they are often found as pollutants in the petrochemical wastewater. This study utilizes ozone to decompose the organic nitrogen contained in acrylonitrile and styrene, and the oxidation process was monitored using on-line measurements of oxidation-reduction potential (ORP) and pH. The efficiency of organic nitrogen decomposition was also estimated based on the COD, organic nitrogen, TOC, ammonia-N, nitrite, and nitrate measurements. Both the initial pH and alkalinity are observed to affect the degradation rate of organic nitrogen. The acrylonitrile sample with the lowest initial pH value (i.e., 4.0) has a shorter t1/2 of 18.9 min and that for samples of the highest initial pH (i.e., 11) was 34 min. The alkalinity of one acrylonitrile sample was boosted by adding 500 mg/l CaCO3, to simulate the field ABS (Acrylonitrile-Butadiene-Styrene) wastewater effluent. It was observed that within a short ozone contact time, the acrylonitrile sample spiked with 500 mg/l CaCO3 had the highest COD decomposition rate of 0.411 min−1, or 1.3 times more than that for samples without addition of CaCO3. Results of the ozonation process can be fitted with a modified Nernst equation for the various pH conditions. Additionally, the ozone treated synthetic ABS sample shows a faster COD removal rate in the subsequent biological process than those samples without ozone treatment.

INACTIVATION OF SALMONELLA TYPHIMURIUM BY SORBIC ACID1

1972 ◽  
Vol 35 (9) ◽  
pp. 532-539 ◽  
Author(s):  
H. S. Park ◽  
E. H. Marth
Keyword(s):  
Acetic Acid ◽  
Lactic Acid ◽  
Salmonella Typhimurium ◽  
Sorbic Acid ◽  
Nutrient Broth ◽  
Ph Adjustment ◽  
Complete Inactivation ◽  
Effective Reduction ◽  
Lag Period ◽  
Complex Foods

Nutrient broth, skimmilk, and evaporated milk at pH 5.0, 5.5, or without pH adjustment and with and without 2,000 and 3,000 ppm sorbic acid were evaluated at 7, 13, and 37 C for their effects on Salmonella typhimurium. The combination of 3,000 ppm sorbic acid and acetic acid at pH 5.0 most effectively inactivated S. typhimurium in all media and at all temperatures. Complete inactivation by this treatment required from 12 hr or less in nutrient broth at 37 C to 55 days in evaporated milk at 7 C. In some instances, treatment with 3,000 ppm sorbic acid combined with lactic acid at pH 5.0 was equally effective. Reduction of sorbic acid concentration to 2,000 ppm or raising the pH of the substrate to 5.5 increased the time needed for inactivation of S. typhimurium. Inactivation of S. typhimurium was most rapid in nutrient broth at 37 C and required progressively more time either as the temperature was reduced or as more complex foods were substituted for the broth. Growth of S. typhimurium occurred at 37 and 13 C in plain nutrient broth, in nutrient broth at pH 5.0 or 5.5, and in nutrient broth with 2,000 or 3,000 ppm sorbic acid (pH not adjusted). Growth in skimmilk occurred under similar conditions except when the pH was reduced to 5.0 with acetic acid. In evaporated milk, growth at both temperatures was possible only in untreated samples and in those acidified to pH 5.5. In some instances, a lag period of 25–29 days occurred at 13 C before growth was evident.

scholarly journals Supported Nanosizedα-FeOOH Improves Efficiency of Photoelectro-Fenton Process with Reaction-Controlled pH Adjustment for Sustainable Water Treatment

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Chuan Wang ◽  
Hong Liu ◽  
Zhimin Sun ◽  
Jian Huang ◽  
Yang Liao
Keyword(s):  
Iron Oxide ◽  
Water Treatment ◽  
Fenton Reaction ◽  
Fenton Process ◽  
Major Step ◽  
Ph Adjustment ◽  
Extra Energy ◽  
Initial Ph ◽  
The Individual ◽  
20 Nm

The overall photoelectro-Fenton (PE-Fenton) process for water treatment with neutral initial pH includes three steps of pH reduction, PE-Fenton reaction, and pH elevation. Reaction-controlled pH adjustment (RCpA), which utilizes the intrinsic electrochemical reactions instead of chemical addition, has been employed to lower the pH, maintain the lowered pH for the Fenton reaction, and recover the pH for final effluent discharge. This study demonstrated that the overall efficiency of this sustainable PE-Fenton process was improved by rapidly recycling the iron substance. Nanosized iron oxide was prepared and employed to ensure such rapid recycling. SEM and XRD results showed that the as-prepared iron oxide wasα-FeOOH with 20 nm in size. The experimental results of dimethyl phthalate (DMP) degradation showed that diatomite-supportedα-FeOOH (N-α-FeOOH/diatomite) could efficiently reduce the DMP concentration and total organic carbon. Furthermore, compared with Fe3+, the N-α-FeOOH/diatomite saved 160 min for iron settlement at 20 mg L−1DMP concentration. Also, with the increment in the initial DMP concentration, extra energy consumed by the individual step of PE-Fenton reaction using the N-α-FeOOH/diatomite became negligible compared with that using free iron ions with the increment in the initial DMP concentration. This development is expected to be a major step of the PE-Fenton process with RCpA towards actual water treatment.

Effect of Initial pH Adjustment on Hydrolysis and Acidification of Sludge by Ultrasonic Pretreatment

2011 ◽  
Vol 50 (22) ◽  
pp. 12372-12378 ◽  
Author(s):  
Xiao-Rong Kang ◽  
Guang-Ming Zhang ◽  
Lin Chen ◽  
Wen-Yi Dong ◽  
Wen-De Tian
Keyword(s):  
Ultrasonic Pretreatment ◽  
Ph Adjustment ◽  
Initial Ph

scholarly journals Ozone-based advanced oxidation process as pre-treatment of wastewater from the wood-based industry

2017 ◽  
Author(s):  
Alexandre Amaro ◽  
Henrik Hanson ◽  
Fabio Kaczala ◽  
Marcia Marques ◽  
William Hogland
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Advanced Oxidation ◽  
Municipal Wastewater Treatment ◽  
Ph Adjustment ◽  
Municipal Wastewater Treatment Plant ◽  
Initial Ph

Three ozone-based advanced oxidation treatments (O3; O3 with initial pH adjustment and; O3/UV with initial pH adjustment) were compared for the treatment of a recalcitrant wastewater generated during washing/cleaning of surfaces and equipment used in filling and gluing processes (urea-formaldehyde and phenol-formaldehyde resins) in a wood-floor industry in Sweden. The wastewater (initial COD 3,400-4,000 mg/L) was obtained at the outlet of a sedimentation tank, which receive an inflow with an average COD of 45,000 mg/L. The experiments were performed in a semi-batch microbubble column reactor connected to a UV reactor, where 2.5 L samples of wastewater were submitted to the maximum dose of 2 g of O3 per gram of initial COD. For the full-factorial design, the independent variables were O3 concentration (g O3/Nm3); recirculation flow (L/min); and initial pH (pHi). The evaluation of the treatment performance was based on COD and TOC reductions (in %), and the effluent obtained was used in respirometric assays with activated sludge obtained at a municipal wastewater treatment plant to assess biodegradability/inhibitory effects. The results showed that ozonation at the original low pH promoted a reduction of 65% and 31% of COD and TOC respectively, but made the effluent less biodegradable. The highest COD and TOC reductions were achieved when O3 /UV treatment with pHi = 9.3 were applied (93% e 56% reductions for COD and TOC respectively). The results with the respirometry tests suggest that application of O3 only at higher pH values promoted biodegradability enhancement of the effluent, making it treatable by microbiota obtained with activated sludge from a municipal wastewater treatment plant.

Comparative Growth Rates of Salmonella typhimurium and Pseudomonas fragi on Cooked Crab Meat Stored Under Air and Modified Atmosphere

1990 ◽  
Vol 53 (7) ◽  
pp. 566-567 ◽  
Author(s):  
STEVEN C. INGHAM ◽  
ROBERT A. ALFORD ◽  
A. PAIGE MCCOWN
Keyword(s):  
Salmonella Typhimurium ◽  
Shelf Life ◽  
Growth Rates ◽  
Modified Atmosphere ◽  
Pseudomonas Fragi ◽  
Three Samples ◽  
Crab Meat

Crab meat packaged in plastic (polypropylene, Fisher) jars was sterilized, cooled, and inoculated with approximately 103 cells/g each of Salmonella typhimurium and Pseudomonas fragi. Inoculated samples were packaged either under air or a commercial modified atmosphere (MA) gas mix containing 50% CO2/10% O2/balance proprietary. These samples were stored at 7 and 11°C. At 0, 2, 4, and 6 d after inoculation, three samples per treatment at each temperature were tested for populations of inoculum species. S. typhimurium did not grow under either atmosphere at 7°C but grew under air and MA at 11 °C. MA-storage slowed the growth of both S. typhimurium and P. fragi at 11°C, although growth of S. typhimurium was more severely inhibited. Use of 50% CO2/10% O2/balance proprietary MA-storage may greatly extend the shelf life of crab meat, but in the absence of proper refrigeration, it cannot be relied upon to eliminate the risk of salmonellosis.

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