Effluent concentrations

Sepa.ra.tion of Plutonium. The principal problem in the purification of metallic plutonium is the separation of a small amount of plutonium (ca 200—900 ppm) from large amounts of uranium, which contain intensely radioactive fission products. The plutonium yield or recovery must be high and the plutonium relatively pure with respect to fission products and light elements, such as lithium, beryUium, or boron. The purity required depends on the intended use for the plutonium. The high yield requirement is imposed by the price or value of the metal and by industrial health considerations, which require extremely low effluent concentrations. 

Design criteria for carbon adsorption include type and concentration of contaminant, hydrauhc loading, bed depth, and contact time. Typical ranges are 1.4—6.8 L/s/m for hydrauhc loading, 1.5—9.1 m for bed depth, and 10—50 minutes for contact time (1). The adsorption capacity for a particular compound or mixed waste stream can be deterrnined as an adsorption isotherm and pilot tested. The adsorption isotherm relates the observed effluent concentration to the amount of material adsorbed per mass of carbon. 

New areas in adsorption technology include carbonaceous and polymeric resins (3). Based on synthetic organic polymer materials, these resins may find special uses where compound selectivity is important, low effluent concentrations are required, carbon regeneration is impractical, or the waste to be treated contains high levels of inorganic dissolved soHds. 

Aquatic toxicity is becoming (ca 1997) a permit requirement on all discharges. Aquatic toxicity is generally reported as an LC q (the percentage of wastewater which causes the death of 50% of the test organisms in a specified period ie, 48 or 96 h, or as a no observed effect level (NOEL), in which the NOEL is the highest effluent concentration at which no unacceptable effect will occur, even at continuous exposure. 

After the tank is filled, pumping is continued and overflow is permitted at the same flow rate. Find the concentration in the tank when it first becomes fuU, and find how long it takes for the effluent concentration to get within 95% of the steady state value. 

The effluent concentration history is the breakthrough curve, also shown in Fig. 16-3. The effluent concentration stays at or near zero or a low residual concentration until the transition reaches the column outlet. The effluent concentration then rises until it becomes unacceptable, this time being called the breakthrough time. The feed step must stop and, for a regenerative system, the regeneration step begins. 

Thus, the effluent concentration becomes zero at Ti Tp = 1/R. The position of the leading edge (a shock front ) is determined from Eq. (16-132) ... 

Impulse An amount of tracer injected instantaneously into a vessel at time zero. The symbol m5(t — a) represents an impulse of magnitude m injected at time t = a. The effluent concentration resulting from an impulse input is designated Cg. 

Residence time, mean The average time spent by the molecules in a vessel. Mathematically, it is the first moment of the effluent concentration from a vessel with impulse input, or ... 

Step An input in which the concentration of tracer is changed to some constant value Cy at time zero and maintained at this level indefinitely. The symbol Cju(t — a) represents a step of magnitude Cy beginning 3.i t = a. The resulting effluent concentration is designated C. ... 

The chief quantities based on tracer tests are summarized in Table 23-4. Effluent concentrations resulting from impulse and step inputs are designated Cg and C , respectively. The initial mean concentration resulting from an impulse of magnitude m into a vessel of volume is C = mfVr- The mean residence time is the ratio of the vessel volume to the volumetric flow rate, t = V fV or t = jo tCg dt/jo Cg dt. The reduced time is t = t/t. 

Continuous. stirred tank reactor (CSTR), with the effluent concentration the same as the uniform vessel concentration. With a mean residence time t = V /V, the material balance is... 

This condition occurs during transition from lapse to inversion and should be observed most frequently near sunset it maybe very transitory or persist for several hours. The shaded zone of strong effluent concentration is caused by trapping by the inversion of effluent carried into the stable layer by turbulent eddies that penetrate the layer for a short distance. 

EPA has compiled significant data on values of k and n for environmentally significant pollutants with typical activated carbons. Assuming equilibrium is reached, the isotherm provides the dose of carbon required for treatment. In a concurrent contacting process, the capacity is set by the required effluent concentration. In a countercurrent process, the capacity of the carbon is set by the untreated waste pollutant concentration. Thus countercurrent contacting is preferrea... 

Methods of estimating gaseous effluent concentrations have undergone many revisions. For a number of years, estimates of concentrations were calculated from the equations of Sutton, with the atmospheric dispersion parameters C, C, and n, or from the equations of Bosanquet with the dispersion parameters p and Q. More common approaches are based on experimental observation that the vertical distribution of spreading particles from an elevated point is... 

For a given combination of filter design and dust, the effluent particle concentration from a fabric filter is nearly constant, whereas the overall efficiency is more likely to vary with particulate loading. For this reason, fabric filters can be considered to be constant outlet devices rather than constant efficiency devices. Constant effluent concentration is achieved because at any given time, part of the fabric filter is being... 

Processes for SS separation may fill three distinct functions in wastewater treatment, namely, pretreatment to protect subsequent processes and reduce their loadings to required levels, treatment to reduce effluent concentrations to required standards, and separation of solids to produce concentrated recycle streams required to maintain other processes. In the first two functions effluent quality is the prime consideration, but where the third function must be fulfilled along with one of the others, design attention must be given to conditions for both the separated solids (sludge) and the process effluent. 

In Section 7, columns C and E you must Indicate the range of influent concentration and treatment efficiency, respectively, lor each treatment system listed. The facility must estimate the efficiency and influent concentration of each air omission treatment system, as the stack test program did not determine influent concentrations. The facility has manufacturers data on the efficiency of each treatment system and should use this information along with effluent concentration data to estimate the influent concentrations. The efficiency estimates for air treatment systems are not based on operating data this must be indicated in column F of Section 7. 

Glaser and Lichtenstein (G3) measured the liquid residence-time distribution for cocurrent downward flow of gas and liquid in columns of -in., 2-in., and 1-ft diameter packed with porous or nonporous -pg-in. or -in. cylindrical packings. The fluid media were an aqueous calcium chloride solution and air in one series of experiments and kerosene and hydrogen in another. Pulses of radioactive tracer (carbon-12, phosphorous-32, or rubi-dium-86) were injected outside the column, and the effluent concentration measured by Geiger counter. Axial dispersion was characterized by variability (defined as the standard deviation of residence time divided by the average residence time), and corrections for end effects were included in the analysis. The experiments indicate no effect of bed diameter upon variability. For a packed bed of porous particles, variability was found to consist of three components (1) Variability due to bulk flow through the bed... 

Figure 4. The influent and effluent concentrations of BOD5 (left) and T-N (right) in the constructed wetland.

Figure 3. Dependence of the NH3 effluent concentrations observed for Ru/MgO on the feed gas composition (fig, 3A, left figure) and on the total pressure. In fig. 3A, trace A was obtained with Pnj / Phj / Paf 1/1/2, trace B with Pn, / Phs / Paf 1/3/0, trace C with Pn, / Phj / Paf 3/1/0, respectively, using a total flow of 120 Nml/min at 20 bar. In fig. 3B, traces A-D (from bottom to top) were obtained at 1 bar, 9 bar, 20 bar and 50 bar, respectively, using a total flow of 40 Nml/min with Pn, / Phj 1/3.

Fig. 2.5 illustrates the effect on the process response of increasing values of k. This shows that the response time of the system is decreased by increasing values of k and that the final effluent concentration leaving the tank is reduced in magnitude. Increasing k has, however, very little influence on the initial rate of response. 

Feed concentration Active zone concentration Deadzone concentration Effluent concentration Ideal tank concentration Total flow rate Fractional by-pass flow By-pass flow rate Dead volume fraction Deadzone exchange flow Rate constant Fractional conversion Fractional deadzone flow... 

Figure 5.12 Sorption breakthrough curves - effect of flow rate of breakthrough capacity (C0 = influent concentration C = effluent concentration).

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