Treatment of Nasal Deviation With Underlying Bony Asymmetry Secondary to Augmentation Rhinoplasty in Asian Patients.

BACKGROUND: In Asian patients, nasal deviation secondary to augmentation rhinoplasty may result from underlying bony asymmetry that was not corrected intraoperatively. Diagnosis and treatment of this condition are complicated by the masking effect of dorsal implants. OBJECTIVES: The authors applied computed tomography (CT) to examine the causes of nasal deviation after augmentation rhinoplasty. CT results were utilized in preoperative planning for revisional surgery. METHODS: Fifteen women with nasal deviation after augmentation rhinoplasty and CT-confirmed bony asymmetry were included in a retrospective study. To correct nasal deviation, the authors performed revisional rhinoplasty with paramedian osteotomy and unilateral placement of extended spreader grafts at the concave side of the keystone region. For patients with concomitant glabella-radix deviation, implants comprising expanded polytetrafluoroethylene or autologous fascia were placed. RESULTS: Of the 15 patients with nasal bony asymmetry, 14 had developmental keystone asymmetry, and 1 had osteotomy-induced keystone deviation. Six patients had developmental glabella asymmetry. Patients received follow-up for an average of 11.2 months (range, 6-24 months). Revisional procedures were considered successful in 13 patients; 2 patients required additional surgery to address residual nasal deviation. CONCLUSIONS: CT is valuable for the diagnosis of postaugmentation nasal deviation owing to underlying bony asymmetry. Paramedian osteotomy with extended spreader grafting at the concave side of the keystone area and correction of the glabella-radix deviation are effective procedures to reposition the nasal axis along the midline of the face.

Intermittent high-pressure sequential bioreactor (IHPSB) with integration of sand filtration system for synthetic wastewater treatment.

A pressurized activated sludge reactor with a sand layer installed at the bottom of the reactor for filtration purposes was employed for treating synthetic organic wastewater. The intermittent high-pressure sequential bioreactor (IHPSB) was pressurized to facilitate efficient oxygen transfer under elevated biomass conditions with pressure released periodically, i.e. aeration, for mixing and exchanging air. The sand layer integrated in the bottom of reactor was employed to separate sludge from treated water during the effluent discharging period. The results show that the proposed system can achieve chemical oxygen demand (COD) removal of higher than 90% under COD loading ranging from 3.3 to 14.3 kg COD/m3/day. SS of the effluent is quite stable and is less than 30 mg/L when MLSS is less than 18,000 mg/L. Oxygen transfer in the IHPSB is quite effective. Dissolved oxygen (DO) ranging from 16 to 10 mg/L was achieved with aeration cycle varying from 3 to 15 min. Thus, IHPSB can be quite energy efficient compared with traditional aerobic activated biological systems and membrane biological reactor systems.

Dissolution of D2EHPA in liquid-liquid extraction process: implication on metal removal and organic content of the treated water.

Effects of pH, extractant/diluent ratios, and metal concentrations on the extent of extractant dissolution during liquid-liquid extraction were investigated. Experimental result shows that D(2)EHPA dissolution increases dramatically at pH above 4, leveling off at pH 6-7. The phenomenon is consistent with deprotonation of D(2)EHPA and the domination of negatively charged D(2)EHPA species at pH of higher than 4. Concentration of D(2)EHPA in the aqueous phase, i.e., the extent of extractant dissolution, drops after addition of metal and decreases with increasing metal concentration. The amount of D(2)EHPA 're-entering' the organic phase is calculated to be 2.04 mol per mol of Cd added, which is quite closed to the stoichiometric molar ratio of 2 between D(2)EHPA and Cd via ion exchange reaction. The effect of metal species on the extent of extractant/metal complexes re-entering is in the order of Cd ≈ Zn ＞ Ag, which might be coincident to the complexation stability of these metals with D(2)EHPA. The extent of extractant dissolution in liquid-liquid extraction process depends on the type and concentration of metal to be removed, pH of aqueous phase, and extractant/diluent ratios.

Concentration and purification of chromate from electroplating wastewater by two-stage electrodialysis processes.

A designed two-stage electrodialysis system is proposed to concentrate and purify chromate from a low pH electroplating wastewater using monovalent selective electrodialysis membranes. With low pH of the raw water (pH 2.2) in the first stage, chromate was presented as HCrO(4)(-) and monovalent ions (HCrO(4)(-), NH(2)SO(3)(-), Na(+) and Cl(-)) were able to pass through the membrane thus chromate was concentrated up to 191%. Higher current density, flowrate and more membrane area all increased the chromium recovery. When pH was adjusted to 8.5 before entering the second stage, the chromate species was presented as divalent CrO(4)(2-) and retained in the concentrated stream, and the rest monovalent ions (NH(2)SO(3)(-), Na(+) and Cl(-)) were separated by passing through the membrane. For example, 45% of the chlorides were separated in this study. The separation efficiencies in the second stage were also increased when the current density, flowrate and membrane area were increased. Electron Spectroscopy for Chemical Analysis was used to examine the surface chromate species for stage 1, and anion exchange membrane showed more chromate fouling comparing to cation exchange membrane due to more adsorption and concentration polarization effects for the anion exchange membrane.

Effect of temperature, hydraulic residence time and elevated PCO2 on acid neutralization within a pulsed limestone bed reactor.

Limestone has potential for reducing reagent costs and sludge volume associated with treatment of acid mine drainage, but its use is restricted by slow dissolution rates and the deposition of Fe, Al and Mn-based hydrolysis products on reactive surfaces. We evaluated a pulsed limestone bed (PLB) reactor (15 L/min capacity) that uses a CO2 pretreatment step to accelerate dissolution and hydraulic shearing forces provided by intermittent fluidization to abrade and carry away surface scales. We established the effects of hydraulic residence time (HRT, 5.1-15.9 min), temperature (T, 12-22 degrees C) and CO2 tension (PCO2, 34.5-206.8 kPa) on effluent quality when inlet acidity (Acy) was fixed at 440 mg/L (pH = 2.48) with H2SO4. The PLB reactor neutralized all H+ acidity (N = 80) while concurrently providing unusually high levels of effluent alkalinity (247-1028 mg/L as CaCO3) that allow for side-stream treatment with blending. Alkalinity (Alk) yields rose with increases in PCO2, HRT and settled bed height (BH, cm) and decreased with T following the relationship (R2 = 0.926; p<0.001): (Alk)non-filtered = -548.726+33.571.(PCO2)(0.5)+33.671.(HRT)+7.734.(BH)-5.197.(T). Numerical modeling showed CO2 feed requirements for a target Alk yield decrease with increases in HRT, T and the efficiency of off-gas (CO2) recycling.

Modeling pesticide volatilization from turf.

Pesticide volatilization models are typically based on equilibrium partitioning of the chemical into solid, liquid, and gaseous phases in the soil environment. In turf systems direct vaporization from vegetation surfaces is a more likely source, and it is difficult to apply equilibrium methods to plant material due to the uncertainties of solid-liquid-gas partitioning. An alternative approach is to assume that pesticide volatilization is governed by the same processes that affect water evaporation. A model was developed in which evapotranspiration values, as determined by the Penman equation, were adjusted to chemical vaporization using ratios of water and chemical saturated vapor pressures and latent heats of vaporization. The model also assumes first-order degradation of pesticide on turf vegetation over time. The model was tested by comparisons of predictions with measurements of volatilization for eight pesticides measured during 3 to 7 d in 11 field experiments. Measured volatilization fluxes ranged from 0.1 to 22% of applied chemical. Pesticides were divided into two groups based on saturated vapor pressures and organic C partition coefficients. One pesticide was selected from each group to calibrate the model's volatilization constant for the group, and the remaining pesticides were used for model testing. Testing results indicated that the model provides relatively conservative estimates of pesticide volatilization. Predicted mean losses exceeded observations by 20%, and the model explained 67% of the observed variation in volatilization fluxes. The model was most accurate for those chemicals that exhibited the largest volatilization losses.