摘要:

Dilute aircraft deicing fluid (ADF) wastewater (5, 10 and 20 g chemical oxygen demand (COD)/L) can be successfully treated in Upflow Anaerobic Sludge Blanket (UASB) reactors at volumetric organic loading rates as high as 10 g COD/L/d, with COD removal efficiencies between 85 and 98 percent. UASB reactors in this study treating ADF solutions of 20 g COD/L at OLR of 19.3 and 38.7 g COD/L/D achieved COD removal efficiencies of 75 and 70 percent, respectively. The maximum specific COD removal efficiency for successful ADF treatment in UASB reactors was 0.7 g COD/g VSS/d.

ISSN:1093-4529    

DOI:10.1080/10934529809376735

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A method for the determination of five halogenated ether priority pollutants using time‐weighted‐average concentrations is described. These compounds permeate through a silicone polycarbonate membrane and are trapped onto a Tenax TA™ adsorbent. Compounds of interest are solvent desorbed by acetone, followed by separation and quantitation by gas chromatography‐mass spectrometry (GC‐MS). A linear relationship was found between the amount of halogenated ether trapped onto the Tenax adsorbent and the product of the concentration of ether in solution and the exposure time. Concentrations ranged from 0.04 to 7.2 mg/L for a twenty‐four hour exposure. The temperature of solution was found to alter the pollutant permeation rate. This sampler offers the advantages of providing time‐weighted‐average concentrations with a relatively simple sampling method.

ISSN:1093-4529    

DOI:10.1080/10934529809376736

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The influence of an anionic surfactant sodium dodecylbenzene sulfonate (DDBS) in the form of either an aqueous solution or microgas dispersion known as colloidal gas aphron (CGA) on the transport of aPsendomonas psendoalcaligenes, strain through a saturated soil matrix was examined. The experiments were conducted in 30‐cm‐long and 6.35 cm internal diameter stainless steel columns packed with a sandy clay loam. A 10‐ml pulse (0.033 pore volumes) of a bacterial suspension containing 1010colony forming units (cfu) per ml was injected, and the column was eluted with either deionized water, a solution of DDBS, or a CGA suspension at a surface loading rate of 0.16 cm/min. The bacterial distributions within the column were similar after the passage of the water and surfactant solutions; however, the distribution of bacteria in the columns and effluent after the passage of the CGA suspension was markedly enhanced. The bacterial concentration in the lower half of the column after the passage of the CGA suspension was 2 to 3 orders of magnitude higher than that observed for either the surfactant or water solutions under similar experimental conditions. The final bacterial density in the effluent after the passage of the surfactant solution was one‐half order of magnitude greater than that in the effluent produced by passage of water. After the passage of the CGA suspension, the total number of bacteria in the effluent was at least 2 or 3 orders of magnitude greater than that obtained by passage of either surfactant or water as the eluting agent, respectively. The results of the study suggests that CGA suspensions can transport bacteria more efficiently than conventional surfactant solutions or water.

ISSN:1093-4529    

DOI:10.1080/10934529809376737

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The present work was undertaken to investigate the treatment of waste drawing oil which is a high‐strength oil/water emulsion commonly used in the cable and wire manufacturings. A semi‐batch ultrafiltration (UF) process was employed to study the treatment process. Experiments were conducted to examine the treatment performance characteristics of the UF membranes of hydrophilic and hydrophobic types and of different pore sizes. The COD (chemical oxygen demand) and copper concentration removal, turbidity (NTU) improvement and conductivity reduction of the UF treatment were experimentally determined. An exponential equation was proposed to empirically correlate the permeate volume to the applied pressure, temperature and mixing speed and the correlation was verified by the observed data. The experimental results have shown that the UF treatment was highly efficient. The quality of the permeate from the UF treatment process was excellent which permits the permeate to be considered for potential reuse without discharge.

ISSN:1093-4529    

DOI:10.1080/10934529809376738

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A plant‐based natural surfactant with potential applications in the remediation of contaminated soils was obtained from the dry fruit pericarps ofSapindus mukorossi,. Kinetics of microbial growth in the natural surfactant solution under batch aerobic conditions was shown to be dependent on the initial concentrations of the surfactant, and a typical diauxic pattern was observed at high concentrations. This unique pattern may be attributed to the two components in the surfactant solutions that are of different biodegradabilities, and to the inhibition effects of the preferential substrate at high concentrations. Based on the generalized Monod equation, a new mathematical model is proposed to account for this growth pattern. During the exponential growth period, specific growth rates (μ) were in the range of 0.0188 and 0.2574 hr‐1, which corresponds a doubling time (tD,), of 3 to 37 hours. Parameters for the Monod model were estimated to be 1.08 hr‐1and 11200 mg/L for μmax, andK,S,, respectively. A model similar to the logistic growth equation was used to express microbial growth at a low concentration range from 200 to 2500 mg/L, and a discrete model was developed to describe the biphasic growth curve at a high concentration of 6000 mg/L. Model parameters were estimated by a non‐linear least‐squares method. The model was in good agreement with the experimental data for the monoauxic growth at low concentrations, and diauxic growth at high concentrations of the surfactant.

ISSN:1093-4529    

DOI:10.1080/10934529809376739

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The simultaneous photodegradation of four phenolic aldehydes by a polychromatic UV radiation was studied in a batch reactor. These phenolic substances, protocatechuic aldehyde (3,4‐dihydroxybenzaldehyde), p‐hydroxybenzaldehyde, syringaldehyde (4‐hydroxy‐3,5‐dimethoxybenzaldehyde) and vanillin aldehyde (4‐hydroxy‐3‐methoxy benzaldehyde), were selected because of they are major pollutants contained in wastewaters produced in some agro‐industrial plants. The degradation levels obtained are reported and the influences of the operating variables, temperature and pH, are established. Also, the quantum yields for the photoreaction of each individual aldehyde are evaluated by means of a competitive kinetic method, and correlated as a function of the temperature.

ISSN:1093-4529    

DOI:10.1080/10934529809376740

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The mathematical model proposed by Marinas et al. (1993) for a bubble column gas‐liquid contactor is refined to described the mass transfer of ozone absorption and decomposition in the aqueous solution with the decomposition rate expression of general reaction orders (not necessarily integers). Three system equations are employed to describe the ozone concentrations in the bulk liquid (CALb), the hold‐up gas (CAGb), and the superficial gas rise velocity (uG), respectively. The variation of uGand the effect of ozone decomposition on the mass transfer, which is reflected by the enhancement factor (Er) defined as the ratio of chemical to pure physical mass fluxes according to the film model of gas liquid absorption, are considered in the refined model. This analysis thus extends the applicability of the model of Marinas et al. (1993) and is of special importance for the ozone mass transfer in the cases of basic solutions and of low mass transfer coefficients, in which the effect of decomposition on absorption is significant. An example of such case is the cyanide wastewater treatment in the strong basic condition.

ISSN:1093-4529    

DOI:10.1080/10934529809376741

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

In this study, industrial wastewater sludges from Tüpraş oil refinery and Fürsan citric acid manufacturing factory were characterized to investigate important parameters for the conditioning and dewatering efficiencies by means of laboratory pressure filtration time (PFT) studies. A preliminary assessment of the most suitable dewatering system (centrifuge, filter press, belt‐press) was also provided on the basis of the experimental results.

ISSN:1093-4529    

DOI:10.1080/10934529809376742

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This paper describe a method of producing bituminized waste forms, having dimensional and mechanical stability like cement‐based waste forms, as well as maintaining their own merits. The bitumen used in sample preparation was a straight‐run distillation bitumen of penetration 60/70. The waste used for the experiment was bottom ash generated from a hazardous wastes incinerator. An addition 1–5 wt % of sulfur was unable to increase the mechanical stability. Addition of spent PE (spent agricultural polyethylene film) by 5, 4, and 3 wt % to the bitumen waste forms with ash contents of 40, 50 and 60 wt %, respectively resulted in maintaining dimensional and mechanical stability. The compressive strength of waste forms containing ash content of 40 wt % and waste PE 20 wt % exhibited compressive strength of 3447 kPa (500 psi), and softening point of 135°C.

ISSN:1093-4529    

DOI:10.1080/10934529809376743

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:1093-4529    

DOI:10.1080/10934529809376744

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor