Mixing Of Effluent Research Articles

Variations in benthic fauna underneath an effluent mixing zone at a marine oil terminal in Port Valdez, Alaska

The distributions of hydrocarbons and infauna in sediments below a permitted mixing zone for the disposal of treated ballast waters in Port Valdez, Alaska were examined annually, 1999–2001. The associations of biological measures and the abundance of selected benthic organisms to total aromatic hydrocarbons (TARO) ranged up to large-sized effects, as compared against minimum-effect criteria (| r|⩾0.63). The apparent sensitivity of three polychaete worms to low levels of hydrocarbons makes them particularly useful as indicators of future changes in spatial distributions of hydrocarbons associated with discharged effluent. In 2001, sediment TARO concentrations decreased and the correlation values of TARO to biotic variables were generally less than in 1999 and 2000. Evidence supports a conclusion of a strong but spatially limited association of some fauna with accumulations of petroleum hydrocarbons in these sediments.

Mineral Toxicity and Physiological Functions in Tree Seedlings Irrigated with Effluents of Varying Chemistry in Sandy Soil of Dry Region

Effluents namely canal water as control (T1); municipal effluent (T2); textile effluent (T3); steel effluent (T4); textile + municipal effluent in 1:1 ratio (T5); steel + municipal effluent in 1:2 ratio (T6); steel + municipal + textile in 1:2:2 ratio (T7); and steel + textile in 1:2 ratio (T8) were added to the seedlings of Acacia nilotica and Eucalyptus camaldulensis. The aim was to monitor the toxic effect of the accumulated mineral ions on the physiological functions and ultimately to utilize these effluents in tree plantation. Foliage mineral concentration, leaf water potential (LWP), rate of photosynthesis (P n ), rate of transpiration (T) and stomatal conductance (g) were recorded. Mineral accumulation increased in the seedlings of T2 treatment. However, the accumulation of Mn, Fe, Cu and Zn was the highest (p<0.001) in the seedlings of T4, T6, T7, and T8 treatments affecting N, P, K, Ca, Mg, and Na concentration. The seedlings of T3 treatment had less Mg, Mn, Fe, Cu, and Zn and medium N, Ca, and P concentration, which were negatively correlated with Na concentration in foliage and the amount added through effluent irrigation. Concentration of N, K, Ca, Mg, and Na was higher in the foliage of A. nilotica whereas P, Mn, Fe, Cu, and Zn were high in E. camaldulensis. Early two months data showed reduction (p<0.01) in P n (87%), T (81%), g (67%), and LWP as a result of metal stresses (toxicity) in T6, T7, and T8 seedlings. E. camaldulensis maintained high LWP and P n and low T and g compared to A. nilotica. High LWP in the seedlings of T2 was associated (p<0.05) high P n , T, and g. However, these physiological parameters lowered in the seedlings of T3 and T5. Seedlings of T1, T2, and T5 maintained high LWP, P n , T, and g throughout the experimental period. These parameters however, decreased (p<0.01) in the seedlings of T3 treatment subsequently through Na induced deficiency of Mg, Ca, Mn, Fe, Cu, and Zn. The enhanced physiological functions in T5 treatment were probably the result of ameliorative effect of municipal effluent through increased mineral status. The study suggests that excess accumulation of Na, Mn, Fe, Cu, and Zn leads to metal toxicity that adversely affects physiology of the tree seedlings. Mixing of effluents and/or removal of excess would ameliorate these toxic effects and could be the better management practices for their use in tree irrigation.

Growth and mineral accumulation in Eucalyptus camaldulensis seedlings irrigated with mixed industrial effluents.

Effects of mixed industrial effluents on growth, dry matter accumulation and mineral nutrient in Eucalyptus camaldulensis seedlings were studied. The objective was to evaluate the adaptability of E. camaldulensis to effluent, tolerance to excess/deficiency of mineral elements and ultimately to determine suitable combinations of industrial/municipal effluent for their use in biomass production in dry areas. Different irrigation treatments were: T(1): good water; T(2): municipal effluent; T(3): textile effluent; T(4): steel effluent; T(5): textile effluent+municipal effluent in 1:1 ratio; T(6): steel effluent+municipal effluent in 1:2 ratio; T(7): steel+textile+municipal effluent in 1:2:2 ratio; and T(8): steel+textile effluent in 1:2 ratio. High concentrations of metal ions and low concentrations of Ca, Mg, K, Na, N and P in soil and seedlings of T(4) resulted in mortality of the seedlings within a few days. Addition of the textile/municipal effluent increased the survival time of the seedlings for two to three months in T(6), T(7) and T(8) treatments. Among the remaining treatments, the seedlings of T(2) attained 131 cm height, 1.97 cm collar diameter, 19 total branches and produced 158 g seedling(-1) of dry biomass at the age of 10 months. The seedling of T(3) produced the least growth and biomass. Growth equivalent to that of the seedlings of T(1) treatment was achieved when municipal effluent was mixed with textile effluent (T(5)). There was a decrease in soil pH, EC, SOC, NH(4)-N, NO(3)-N, PO(4)-P and basic cations and increase in the concentration of Cu, Fe, Mn and Zn with T(4) treatment. The reverse trend was observed in T(3) where a high concentration of Na might have reduced Mg and micronutrient concentration in seedlings potentially affecting root and leaf growth. Mixing of effluents may be useful in tree irrigation to increase biomass productivity, which is evidenced by improved growth in T(5) and survival in T(6), T(7) and T(8) treatments. Further, reduction of toxic concentration of metal ions in effluents may be helpful for a long-term field application.

Carbohydrate-derived chlorinated compounds in ECF bleaching of hardwood pulps: formation, degradation, and contribution to AOX in a bleached kraft pulp mill.

Five monochlorinated compounds derived from glucuronoxylan were identified in the liquid process streams of a kraft pulp mill producing hardwood pulp with ECF bleaching, representing ca. 15-20% of the AOX of the bleaching filtrates. The environmental risk of such compounds is negligible because a major fraction (70-80%) is degraded during effluent mixing and neutralization, and about 20-30% is degraded during the biological treatment of the mixed effluent. Only less than 3.5% (0.009-0.017 kg/ tAD) of the compounds formed in the bleaching leave the mill in the final effluent.

Aluminium speciation in effluents and receiving waters.

The respective speciation of aluminium in sewage effluent and in river water receiving effluent, has been examined. Results showed that concentrations of reactive aluminium changed over a timescale of hours and were controlled predominantly by pH. A minimum concentration of reactive aluminium occurred at a pH of approximately 6.8, coinciding with the prevalence of non-reactive, insoluble Al(OH)3 species. For receiving waters of low pH value, typically < pH 5, a large proportion of the 'naturally present' aluminium can be present in a reactive form at concentrations higher than the proposed Environmental Quality Standard (EQS). Mixing of waters of this type with effluent of a higher pH value leads to the precipitation of aluminium hydroxide. Mixing of effluent of pH value in the range 7.5-8.0 with river water in the same (or slightly higher) pH range appears to result in no appreciable change in the proportion of reactive aluminium; the change in concentration tends to be related simply to dilution. On the basis of a theoretical knowledge of aluminium speciation, results obtained in this work indicate that it is possible to make predictions about the proportion of reactive aluminium present in a receiving water, based on the pH values of the effluent water mixture and the concentration in the effluent. Reasonable comparisons between measured and predicted values were obtained at higher pH values, but the relationship was less certain at pH values less than 6.5 for which levels of reactive metal tended to be higher than the quality standard value.

The origin of aluminum flocs in polluted streams.

About 240,000 square kilometers of Earth's surface is disrupted by mining, which creates watersheds that are polluted by acidity, aluminum, and heavy metals. Mixing of acidic effluent from old mines and acidic soils into waters with a higher pH causes precipitation of amorphous aluminum oxyhydroxide flocs that move in streams as suspended solids and transport adsorbed contaminants. On the basis of samples from nine streams, we show that these flocs probably form from aggregation of the epsilon -Keggin polyoxocation AlO4Al12(OH)24(H2O)12(7+)(aq) (Al13), because all of the flocs contain distinct Al(O)4 centers similar to that of the Al13 nanocluster.

Hyphenation of capillary high-performance liquid chromatography with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for nano-scale screening of single-bead combinatorial libraries.

This paper focuses on the technical aspects of chemical screening from 384-well plate nano-scale single-bead combinatorial libraries. The analytical technique utilized is a combination of capillary liquid chromatography with ultraviolet detection and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The HPLC/MALDI-MS hyphenation is achieved by means of a micro-fraction collector with a peak detection system that automatically collects the peaks onto the MALDI targets for subsequent characterization. Several experimental parameters such as type of 384-well plate, well-plate sealing foils, and a column-switching procedure were investigated using a small test library of nine components. Additionally, the influence of different MALDI matrices, different MALDI targets and sample-spotting techniques on the MALDI detection sensitivity as well as the ruggedness and sample throughput capacity of this technique were studied. Optimum results for the analytes investigated were obtained with 2,5-dihydroxybenzoic acid using on-line mixing of HPLC effluent and matrix solution. To demonstrate the potential of this capillary HPLC/MALDI-TOFMS method, its application to several single-bead libraries was investigated. The instrumental method allowed for the rapid identification and purity assessment of combinatorial libraries with detection limits down to the higher femtomole level using both UV detection and MALDI mass spectrometry.

Modeling the Mixing of Wastewater Effluent Discharged from Ocean Outfalls using a Hybrid Model

A hybrid model in which line plume equations are used for the computation of the initial mixing in the near field and a random-walk particle-tracking model is used for the simulation of the far field transport was developed to predict the mixing characteristics of wastewater effluent plumes discharged from ocean outfalls. In the particle-tracking model, the governing equation is transformed to the σ coordinate to use grid velocities computed by the σ-layered hydrodynamic model. In addition, the particles introduced at the end of the near field are distributed with the normal distribution to represent the vertical concentration distribution of the wastewater plume. The results of model applications to the Masan sea outfall in Korea show that there is no large difference between the minimum dilutions for the summer and winter seasons even though the effluent plume is trapped at mid-depth during the summer season due to density stratifications. The periodic variation of the ambient current does not have a significant effect on near field dilutions, since the ambient velocities at the outfall site are quite low. The simulation results of the far field transport with settling processes reveal that concentrations at the bottom layer in the vicinity of the outfall site Eire higher than those in the remote sites from the outfall. This simulated result agrees with the depositional trend of the contaminated sediment that was obtained from the field survey.

Design of cooling systems for effluent temperature reduction

Temperature restrictions on aqueous effluents dictate that streams with a temperature higher than the permitted level needed to pass through cooling systems to reduce the effluent temperature before discharge. This paper introduces methods for the design of effluent cooling systems. Inappropriate mixing of effluents with different temperatures reduces opportunities to recover heat from effluents and degrades driving forces for cooling systems. A new systematic method is introduced for the segregation strategy for effluents to deal with effluent temperature problems most effectively by a combination of heat recovery and effluent cooling. This can lead to distributed effluent cooling systems. The design procedure sets targets before design. A design procedure then allows the targets to be achieved by following design rules for distributed cooling. An optimisation model has been developed to search for the most economic design of cooling systems. A case study involving retrofit is presented to illustrate the design methodology and the optimisation model of cooling systems.

Modeling the mixing of heated water discharged from a submerged multiport diffuser

The mixing of heated water which is discharged from a submerged multiport diffuser was analyzed using the three-dimensional grid-based numerical model. The discharge momentum flux is properly incorporated into the model using the concept of a numerical slot diffuser, along with multi-jet theory. Plane or line patch was introduced to impose discharge momentum flux which plays an important role in mixing of the thermal effluent in the near field. The laboratory experimental work has been conducted to investigate mixing characteristics of the coflowing diffuser. A comparison of model simulations with laboratory experiments show that the proposed model properly simulates the shapes of thermal plumes and the distributions of excess temperature. The proposed model properly simulates velocity induced by a coflowing diffuser in proximity to a shoreline boundary, and this is confirmed by Lee's experiments.

Is Small Molecule Clearance Dependent on Timing of Serum Sample and Mixing of Effluent in Ccpd Patients?

Is Small Molecule Clearance Dependent on Timing of Serum Sample and Mixing of Effluent in Ccpd Patients?

Changes in dissolved and particulate copper following mixing of POTW effluents with Delaware River water

Effluents from publicly owned treatment works (POTWs) were mixed with Delaware River water at ratios of 1:1 or 1:2 effluent to Delaware River water. These mixing experiments were performed at pH 6, ambient pH and pH 8. In all mixing experiments, copper was released from effluent particulate matter when mixing was conducted at pH 6. No copper release was observed for mixing at the ambient pH of the samples. At pH 8, no copper was released when effluent from the Delcora or Camden POTWs was mixed with Delaware River water, but copper was released for Levittown, Philadelphia Northeast, Philadelphia Southwest and Gloucester effluents mixed with Delaware River water. The fraction dissolved of total recoverable copper was evaluated statistically at pH 6, ambient pH and pH 8. Because there was no copper released at ambient pH of mixing, we conclude that POTWs may be overregulated on the basis of total recoverable metal concentration as required by the National Pollutant Discharge Elimination System (NPDES). This is due to the fact that effluent particulate copper, which is the majority of the total recoverable copper, does not change to dissolved copper at the ambient pH of the river. Receiving water quality is evaluated on the basis of dissolved copper.

Use of Rhodamine-WT Dye to Map Effluent Mixing Zones in Lake Dillon, Summit County, Colorado

ABSTRACT The Breckenridge Sanitation District discharges tertiary-treated sewage effluent into Lake Dillon, Colorado, a major water supply reservoir for Denver. The effluent plume was mapped using rhodamine-WT dye during ice-covered and open-water conditions and compared to a criterion issued in a U.S. Environmental Protection Agency policy statement regarding mixing-zone dilution. Rhodamine-WT dye was used as a tracer and was injected directly into the sewage effluent at the outlet of the treatment plant. Dye concentrations were determined using fluorometric analysis. Dye-concentration isolines were determined by interpolation of a rectangular sampling grid. At all sampling locations, plateau dye concentrations were reached within 48 hours after injection began. Results indicated that the Breckenridge Sanitation District's effluent mixing zone extended 158.5 m (520 ft) into the lake during ice-covered conditions on March 15, 1995 (the date of maximum effluent discharge during the study period) and extended 64 m (210 ft) during open-water conditions on September 13, 1995. The EPA criterion for lakes specifies that the maximum allowable length of a mixing zone not exceed 61-m (200 ft).

Determination of the mycotoxin moniliformin in cereals by high-performance liquid chromatography and fluorescence detection

The development of a selective and sensitive high-performance liquid chromatography-fluorescence assay for the determination of the mycotoxin moniliformin in plant extracts is described. By means of introducing a derivatization reaction with 1,2-diamino-4,5-dichlorobenzene (DDB) we succeeded in increasing the overall determination sensitivity and the chromatographic selectivity on a RP-HPLC system. Due to the phenolic character of the derivative a bathochromic UV shift from 315 to 330 nm (phenole→phenolate) at pH 10–12 was observed. Moreover, and in contrast to the DDB reagent at pH 10–12 the moniliformin-DDB derivative showed fluorescence activity with λ Ex=330 nm and λ Em=440 nm, which led to the benefits that the excess of DDB did not have to be removed from the sample solution. The pH-shift was accomplished via on-line post-column effluent mixing of the RP-18 eluent using an auxiliary HPLC pump and a buffer of pH 12.00. The fluorescence detection enables the reduction of the determination limit of moniliformin from 0.05 (UV detection) to 0.02 mg/kg maize.

EXPERIMENTAL AND MODELING STUDIES OF STAGED COMBUSTION USING A REACTOR ENGINEERING APPROACH

Abstract Combustion research, long dominated by mechanical engineers, is becoming increasingly a chemical engineering application. It is therefore desirable to have a well defined reactor in which to conduct combustion chemistry studies. A two zone laboratory reactor emulating a perfectly stirred reactor + plug flow reactor (PSR + PFR) sequence has been constructed and validated for use in high temperature normal and staged combustion studies. A premixed fuel/eed enters the backmixed primary zone. The effluent mixes with additional injected oxidant and/or steam, and then enters the linear flow secondary zone. Extracted gas samples from cooled probes located in each zone are subjected to several dedicated on-line stack gas analyzers, and separation/analyses by on-line gas chromatography. Detailed reaction mechanisms from the literature are incorporated into a PSR + PFR reactor engineering model. The experimental feed rates and measured temperatures are also input to the model. Good comparisons between mode...

Near-field mixing at an outfall

The near-field mixing of effluent from buoyant and nonbuoyant flows from outfalls discharging into a cross-flowing ambient current in trapezoidal channels has been investigated. A physical model was scaled to represent a typical large outfall into one of the connecting channels of the Great Lakes system. The discharged jet was measured in detail to determine the velocity and concentration fields. The excess velocities and concentrations were found to follow the Gaussian distribution. Empirical expressions for the jet trajectories, minimum dilutions, and plume widths were derived. A correction factor has been introduced to the concentration distribution to ensure mass conservation. The calibrated model was verified by comparison with field data and the results of other near-field models (PDS, MIT, and CORMIX). Key words: mixing, near field, pollutant transport, outfall, buoyant flow, non-buoyant flows.

Seawater quality at industrial effluents discharge zone

Shuaiba Industrial Area (SIA) accommodates 38 plants, of which 15 are located in the eastern sector and the other 23 in the western sector. The factories, being near the shore of the Arabian Gulf, discharge their wastewater directly into the Gulf after in-plant treatment. How far industrial effluents influence the marine environment was assessed using Microtox toxicity assays of seawater samples collected twice a week for six months from two stations located upstream and downstream of SIA. Out of 50 samples each collected from Station No 1 and Station No 2, only two samples from the former showed toxicity, whereas at the latter site ten samples showed medium to high levels of toxicity. The higher incidence of toxicity in the downstream area may be due to the mixing of effluent from individual discharges and indicate some inefficiency of the effluent treatment process. The study revealed that the biological assay provides effective assessment of water quality.

Modeling the Effects of Variable Groundwater Chemistry on Adsorption of Molybdate

Laboratory experiments were used to identify and quantify processes having a significant effect on molybdate (MoO42−) adsorption in a shallow alluvial aquifer on Cape Cod, assachusetts. Aqueous chemistry in the aquifer changes as a result of treated sewage effluent mixing with groundwater. Molybdate adsorption decreased as pH, ionic strength, and the concentration of competing anions increased. A diffuse‐layer surface complexation model was used to simulate adsorption of MoO42−, phosphate (PO43−), and sulfate (SO42−) on aquifer sediment. Equilibrium constants for the model were calculated by calibration to data from batch experiments. The model was then used in a one‐dimensional solute transport program to successfully simulate initial breakthrough of MoO42− from column experiments. A shortcoming of the solute transport program was the inability to account for kinetics of physical and chemical processes. This resulted in a failure of the model to predict the slow rate of desorption of MoO42− from the columns. The mobility of MoO42− ncreased with ionic strength and with the formation of aqueous complexes with calcium, magnesium, and sodium. Failure to account for MoO42− speciation and ionic strength in the model resulted in overpredicting MoO42− adsorption. Qualitatively, the laboratory data predicted the observed behavior of MoO42− in the aquifer, where retardation of MoO42− was greatest in uncontaminated roundwater having low pH, low ionic strength, and low concentrations of PO43− and SO42−.

Seawater quality at industrial effluents discharge zone

Shuaiba Industrial Area (SIA) accommodates 38 plants, of which 15 are located in the eastern sector and the other 23 in the western sector. The factories, being near the shore of the Arabian Gulf, discharge their wastewater directly into the Gulf after ill-plant treatment.How far industrial effluents influence the marine environment was assessed using Microtox toxicity assays of seawater samples collected twice a week for six months from two stations located upstream and downstream of SIA.Out of SO samples each collected from Station No 1 and Station No 2, only two samples from the former showed toxicity, whereas at the latter site ten samples showed medium to high levels of toxicity. The higher incidence of toxicity in the downstream area may be due to the mixing of effluent from individual discharges and indicate some inefficiency of the effluent treatment process. The study revealed that the biological assay provides effective assessment of water quality.

A Two Zone Turbulent Flow Reactor Facility for Studies of Staged Combustion of Simulated Hazardous Wastes

Abstract A two zone turbulent flow laboratory reactor has been constructed and validated for use in staged combustion studies. A premixed fuel/air feed enters the toroidal backmixed primary zone. The effluent mixes with additional injected oxidant and/or steam, and then enters the linear flow secondary zone. This sequence emulates many large scale combustors. Extracted gas samples from cooled probes located in each zone are subjected to several dedicated on-line gas analyzers, and separation/analyses by on-line/batch gas chromatography. Modeling of the combustor is performed with detailed reaction mechanisms and an idealized perfectly stirred reactor + plug flow reactor sequence. The experimental feed rates and measured temperatures are input to the model. Staged combustion for NO minimization has been demonstrated for an ethylene/monomethyl amine feed