Academic literature on the topic 'Processes post-discharge kinetic'

For multi-section drainage facilities, it is important to develop operational measures based on maneuvering moving barriers. Maneuvering of moving barriers is a measure that carries out the flow of water from the upper reaches to the lower reaches at the required level, taking into accounts the design features and operational mode of the hydraulic regime of the drainage structure. The maneuvering mode in the flow of water from the discharge structures ensures the order of opening, phasing, and level of opening of these movable barriers. Hydraulic conditions are associated with the effective control of the hydraulic regime in the lower part of the drainage structure or the suppression of excess kinetic energy, the reversal of the flow, or the prevention of post-riser deformation processes. Creating conditions ensuring that the hydrotechnical and hydropower construction of the water transfer or discharge facility is adapted for use in conjunction with a hydropower plant, water intake, sluices, and flow control system.

Biogas production considered the most encouraging sources of renewable energy in Sudan. Anaerobic process of digestion is considered as efficient techniques of producing biogas. The process also a trustworthy method for treatment of municipal wastes, and the digested discharge could be utilized as soil conditioner to improve the productivity. This research work states at the option of using domestic sludge of the wastewater treatment plant in Soba municipal station (south of Khartoum-Sudan) to produce biological gas (biogas). A laboratory investigation was carried out using five-liter bioreactor to generate biogas for 30 days. The total volume of gas made was 270.25 Nml with a yield of 20 Nml of biogas/mg of COD removed. Chemical oxygen demand, Biological oxygen demand, & total solids drop produced were 89, 91 & 88.23% respectively. Microbial activity was declined from 1.8x107 (before starting the process of digestion) to 1.1x105 germs/mL (after completion of 30 days of digestion). This study offered a significant energetic opportunity by estimated the power production to 35 KWh.Key word: Sludge, municipal plant, organic material, anaerobic process, breakdown, biological gas potentialNTRODUCTIONIncreasing of urban industries style in the world has given rise to the production of effluents in huge amounts with abundant organic materials, which if handled properly, be able to end in a substantial source of energy. Although of a fact that there is an undesirable environmental effect related with industrialization, the influence can be diminished and energy can be tapped by means of anaerobic digestion of the wastewater (Deshpande et al., 2012). Biological wastewater treatment plant (WWTP) is a station for removal of mainly organic pollution from wastewaters. Organic materials are partly transformed into sludge that, with the use of up-to-date technologies, represents an important energy source. Chemical biological, and physical technology applied throughout handling of wastewater produce sludge as a by-product. Recent day-to-day totals, dry solids range from 60–90 g per population equivalent, i.e. EU produces per year 10 million tons of dry sludge (Bodík et al., 2011). Sludge disposal (fertilizers use, incineration, and landfills) is often explored since of increasingly limiting environmental legislation (Fytili and Zabaniotou, 2008). The energy present in sludge is obviously consumed in anaerobic digestion. Anaerobic Process is considering the most appropriate choice for the handling of organic effluents of strong content. This process upgraded in the last few years significantly with the applications of differently configured high rate treatment processes, particularly for the dealing of industrial releases (Bolzonella et al., 2005). Anaerobic process leads to the creation of biological gas with high content of methane, which can be recovered, and used as an energy source, making it a great energy saver. The produced gas volume during the breakdown process can oscillate over a wide range varying from 0.5 – 0.9 m3 kg–1 VS degraded (for waste activated sludge) (Bolzonella et al., 2005). This range rest on the concentration of volatile solids in the sludge nourish and the biological action in the anaerobic breakdown process. The residue after digestion process is stable, odorless, and free from the main portion of the pathogenic microorganism and finally be able to use as an organic nourishment for different application in agriculture. Sludge significant coming out from breakdown which allows to yield a renewable energy, that was cheap, obtainable, & no polluting. Sustainable development considered the production of biogas as environmentally friendly and an economic key (Poh and Chong, 2009).OBJECTIVES Sudan have huge tones of sewage sludge from domestic sewage water is accumulated daily in lagoon of soba sewage treatment plant, so this work, we were carried for energy production and treatment of sludge, which constitutes a plentiful waste which ever know any sort of handling after few years from establishing the station.MATERIALS AND METHODSExperimental apparatus: Anaerobic breakdown was done in five liters fermenter. The fermenter was maintained at 35oC in a thermostatic bath and stirred regularly. U shaped glass tube was connected to the fermenter, allowing the measurement of produced biogas volume and pressure. Water displacement technique was used for determination of the volume of produced biological gas (biogas) at the beginning of each sampling. Testing of the biogas combustibility was determined by connecting one of ends of the tube to a gas collection and storage device (balloon), the other end to a Bunsen burner. In the process of reduction of carbon dioxide (CO2) to maximum dissolution in the tube the liquid must be a salty saturated acid solution (5% citric acid, 20% NaCl, pH ¼ 2) (Connaughton et al., 2006).Substrate: About 5L sludge containing culture medium were taken from the lowest part of the first settling tank in Soba station. The moisture content of initial substrate was 35%. The collected sample was preserved at 4oC prior to loading the biological reactor (Tomei et al., 2008). Table 1 showed the sludge features in the reactor with a loading rate of 16 g TS/L, (Connaughton et al., 2006; Tomei et al., 2008).Analytical Methods: The pH was controlled by using HANNA HI 8314 model as pH meter device. Assay was used for determination of Alkanility & Volatile fatty acids (Kalloum et al., 2011). The standard method of analysis was used for recognized the Chemical Oxygen Demand (COD) (Raposo et al., 2009). Titrimetric method was used for analyzing Volatile fatty acids (VFA). Alkalinity assay was used for determination of Total Alkalinity (TA). Oxitop assay was used for measuring the biological oxygen demand. Ignition method was used for measuring Volatile Solids (VS) by losing weight in dry sample at 550oC in the furnace, & Total solids were done to constant weight at 104oC (Monou et al., 2009). A method of water displacement was used for determination of the total volume of Biological gas produced (Moletta, 2005). Microbial species & analyses were determined by microbial standard assay. Sample analysis was done by explore of three replicates and the outcomes were the middling of these replicates. Startup of experiments continues until a bubble of gas was detected.RESULTS AND DISCUSSIONMeasurement of pH: Figure 2 exhibited pH trends during 30 days with a drop pattern from 7.0 to 6.0 during the first five days; this was mainly because of the breakdown of organic materials and the development of (VFA). Then later, an increasing pattern in pH was noticed to 6.98, for the next week, then Steadying around this pH level was continued till the completion of the breakdown period which taken 30 days. Those out comes were also reported by other researchers (Raposo et al., 2008)Measurement of VFA: Development of VFA throughout 30 days was depicted in figure 3, an increase in volatile fatty acids up to 1400 mill equivalents per liter (meq/L) in the first ten days. This criterion of making of volatile fatty acid is typical to the researcher’s report of identification of hydrolysis in acidogenesis stage (Parawira et al., 2006). The decline in volatile fatty acids after the tenth day was owing to intake by bacteria which would relate to the stage of acetogenesis.Total alkalinity (TA): During the ten days, we observed rise in volatile fatty acids content followed by a drop in a pH in the same time (figures 4 and 5). Encountered to these alterations, an increase in the total alkalinity in the medium for reestablishing situations of alkalinity to the outbreak of methanogens stage (figure 4). Through all the digestion period the ratio of VFA/TA which was equal and lower than 0.6±0.1 were described in figure 6. These ratios designated the achievability of the procedure despite the essential production of volatile fatty acid (Chen and Huang, 2006; Nordberg et al., 2007). The anaerobic digestion process may be hinder by the production of volatile fatty acid.Biogas production: Pressure measurement and biogas volume were used for controlling biogas production. Figure 7 explained the changing in biogas pressure throughout the digestion period. quality of Biogas was obtained with minimum methane of 40% (Bougrier et al., 2005; Lefebvre et al., 2006). Total volume of biological gas production was 270.25 Nml. The yield of biological gas was 20.25 Nml/mg COD removed, which is in range of the others researcher report (Tomei et al., 2008). Biogas production can be calculated from the following formula (Álvarez et al., 2006): Biogas production= (Total quantity of biogas produced)/(Total solid).The COD and BOD removal: Chemical oxygen Demand (COD) and Biological Oxygen Demand (BOD) showed a significant reduction of 89% and 91% respectively (figures 8 and 9). Consequently these reduction in contaminants proved that anaerobic process of digestion was an operational technique for removal of organic pollution. Some researchers reported the same results (Bolzonella et al., 2005; Álvarez et al., 2006; Wang et al., 2006). Another criterion for proving the removal of organic pollutants was reduction of total solids (TS), where the drop approached 88.23% (figure 10). Some researcher’s reports approached the same drop (Hutnan et al., 2006; Linke, 2006; Raposo et al., 2009). Therefore it was possible to conclude that anaerobic digestion necessary showed decrease or reduction of organic pollutants rates because of the transformation of organic substances into biogas and accordingly led to the drop of chemical oxygen demand (COD). This could be explained in figure 11 by the comparison of the two techniques during the anaerobic digestion process. That means the chemical oxygen demand (COD) drop should be tailed essentially by Total solids drop (TS).Microbial activity: Figure 11 showed the microbial variation during anaerobic digestion. The total micro flora (total germs) declined from 1.8x107 (before starting the process of digestion) to1.1x105 germs/mL (after completion of 30 days of digestion). Moreover figure 12 obviously explained what was running during the process of digestion in the reactor, microbial species vanishing after the 30 days such as streptococci and Escherichia coli. Some researchers reports explained that there was some sort of relationship between physicochemical and the biological parameters of micro flora with total solid (TS). figure 13 described obviously this relationship of the drop of micro flora which go along with total solids reduction. This intended that consumption and a declining in the mass residue of organic materials created at the termination of digestion was the outcome of the transformation of organic materials into biological gas and also the sum of microorganism reduction. This attained result proved that the process of anaerobic digestion was a good process for decontamination (Deng et al., 2006; Perez et al., 2006; Davidsson et al., 2007).CONCLUSIONSoba sludge’s municipal station carried in this research paper demonstrated operative for biological gas production (biogas). During the first five days, breakdown of organic materials and the formation of volatile acids were started. Volatile fatty acids increased up to 1400 mill equivalents per liter (meq/L) in the first ten days, then started to decline in after the tenth day this owing to intake by bacteria which would resemble to acetogenesis stage. The biogas production lasted until the 21th day then starting decreasing till the last day (30 day) this due to instability of the culture medium of fermentation which became completely poor. COD and BOD showed a significant reduction of 89% and 91% respectively. Another criteria for proving of removal rate of organic pollutants was reduction of total solids (TS), where the reduction rate approached 88.23%. Total volume of biological gas production was 270.25 Nml. The yield of biological gas was 20.25 Nml/mg COD removed, which is in range of the others researcher report. The total micro flora (total germs) declined from 1.8x107 (before starting the process of digestion) to 1.1x105 germs/mL (after completion of 30 days of digestion). Study proved that process of anaerobic digestion was a good process for decontamination. Industries and will be usefulness for bioremediation in marine environment and petroleum industry.ACKNOWLEDGMENTSThe authors wish to express their appreciation to Soba treatment plant, for their financial support of this research.CONFLICT OF INTERESTThe authors wish to express their appreciation to Soba treatment plant, for their financial support of this research.REFERENCES Álvarez, J., I. Ruiz, M. Gómez, J. Presas and M. Soto, 2006. Start-up alternatives and performance of an uasb pilot plant treating diluted municipal wastewater at low temperature. Bioresource technology, 97(14): 1640-1649.Bodík, I., S. Sedláček, M. Kubaská and M. Hutňan, 2011. Biogas production in municipal wastewater treatment plants–current status in eu with a focus on the Slovak Republic. Chemical biochemical engineering quarterly, 25(3): 335-340.Bolzonella, D., P. Pavan, P. Battistoni and F. Cecchi, 2005. Mesophilic anaerobic digestion of waste activated sludge: Influence of the solid retention time in the wastewater treatment process. Process biochemistry, 40(3-4): 1453-1460.Bougrier, C., H. Carrere and J. Delgenes, 2005. Solubilisation of waste-activated sludge by ultrasonic treatment. Chemical engineering journal, 106(2): 163-169.Chen, T.-H. and J.-L. Huang, 2006. Anaerobic treatment of poultry mortality in a temperature-phased leachbed–uasb system. Bioresource technology, 97(12): 1398-1410.Connaughton, S., G. Collins and V. O’Flaherty, 2006. Psychrophilic and mesophilic anaerobic digestion of brewery effluent: A comparative study. Water research, 40(13): 2503-2510.Davidsson, Å., C. Gruvberger, T. H. Christensen, T. L. Hansen and J. la Cour Jansen, 2007. Methane yield in source-sorted organic fraction of municipal solid waste. Waste management, 27(3): 406-414.Deng, L.-W., P. Zheng and Z.-A. Chen, 2006. Anaerobic digestion and post-treatment of swine wastewater using ic–sbr process with bypass of raw wastewater. Process biochemistry, 41(4): 965-969.Deshpande, D., P. Patil and S. Anekar, 2012. Biomethanation of dairy waste. Research journal of chemical sciences, 2(4): 35-39.Fytili, D. and A. Zabaniotou, 2008. Utilization of sewage sludge in eu application of old and new methods—a review. Renewable sustainable energy reviews, 12(1): 116-140.Hutnan, M., M. Drtil and A. Kalina, 2006. Anaerobic stabilisation of sludge produced during municipal wastewater treatment by electrocoagulation. Journal of hazardous materials, 131(1-3): 163-169.Kalloum, S., H. Bouabdessalem, A. Touzi, A. Iddou and M. Ouali, 2011. Biogas production from the sludge of the municipal wastewater treatment plant of Adrar city (Southwest of Algeria). Biomass bioenergy, 35(7): 2554-2560.Lefebvre, O., N. Vasudevan, M. Torrijos, K. Thanasekaran and R. Moletta, 2006. Anaerobic digestion of tannery soak liquor with an aerobic post-treatment. Water research, 40(7): 1492-1500.Linke, B., 2006. Kinetic study of thermophilic anaerobic digestion of solid wastes from potato processing. Biomass bioenergy, 30(10): 892-896.Moletta, M., 2005. Characterization of the airborne microbial diversity of biogas. In: PhD diss. Montpellier 2.Monou, M., N. Kythreotou, D. Fatta and S. Smith, 2009. Rapid screening procedure to optimise the anaerobic codigestion of industrial biowastes and agricultural livestock wastes in cyprus. Waste management, 29(2): 712-720.Nordberg, Å., Å. Jarvis, B. Stenberg, B. Mathisen and B. H. Svensson, 2007. Anaerobic digestion of alfalfa silage with recirculation of process liquid. Bioresource technology, 98(1): 104-111.Parawira, W., M. Murto, R. Zvauya and B. Mattiasson, 2006. Comparative performance of a uasb reactor and an anaerobic packed-bed reactor when treating potato waste leachate. Renewable energy, 31(6): 893-903.Perez, M., R. Rodriguez-Cano, L. Romero and D. Sales, 2006. Anaerobic thermophilic digestion of cutting oil wastewater: Effect of co-substrate. Biochemical engineering journal, 29(3): 250-257.Poh, P. and M. Chong, 2009. Development of anaerobic digestion methods for palm oil mill effluent (pome) treatment. Bioresource technology, 100(1): 1-9.Raposo, F., R. Borja, M. Martín, A. Martín, M. De la Rubia and B. Rincón, 2009. Influence of inoculum–substrate ratio on the anaerobic digestion of sunflower oil cake in batch mode: Process stability and kinetic evaluation. Chemical engineering journal, 149(1-3): 70-77.Raposo, F., R. Borja, B. Rincon and A. Jimenez, 2008. Assessment of process control parameters in the biochemical methane potential of sunflower oil cake. Biomass bioenergy, 32(12): 1235-1244.Tomei, M., C. Braguglia and G. Mininni, 2008. Anaerobic degradation kinetics of particulate organic matter in untreated and sonicated sewage sludge: Role of the inoculum. Bioresource technology, 99(14): 6119-6126.Wang, J., D. Shen and Y. Xu, 2006. Effect of acidification percentage and volatile organic acids on the anaerobic biological process in simulated landfill bioreactors. Process biochemistry, 41(7): 1677-1681.

A huge number of experiments were carried out in the field of nitrogen post-discharges during the last 50 or 60 years and they were supported by many published theoretical works. Some papers were focused also on the nitrogen active discharge, post-discharge itself, or they focused mainly on the kinetic processes running during the post-discharge period. This experimental work shows how oxygen titration into post-discharge will influence nitrogen flowing post-discharge. Experimental data were obtained by optical emission spectrometry, Spectra were measured in the range 300 - 700 nm at laboratory temperature of 300K. Discharge current was kept constant at the value of 120 mA relating to the total discharge power of 145 W. Pressure was kept constant, too, at the value of 1000 Pa. The nitrogen of 99.9999 % purity (further purified by Oxiclear column) flow was adjusted at 0.8 l/min. Flow of oxygen (99.95 % purity) through he titration capillary introduced to post-discharge from down stream direction, was kept at 4 ml/min. Both gas flows were controlled by mass flow controllers. The optical emission spectrometer Jobin Yvon TRIAX 550 with 300 gr/mm grating equipped by liquid nitrogen cooled CCD detector was used for the spectra acquisition. The integration time of 1 s was used at all experiments. The position of titration tube end introduced into post discharge from the down stream side was set from 5 to 25 cm with respect to the end of the active discharge; the step of 1 cm was used. The optical emission spectra were measured at positions from 3 to 29 cm with respect to the active discharge end. The following nitrogen spectral systems were identified in the spectra: 1st positive, 1st negative and 2nd positive. Besides them, some bands of NO-beta system were found. The intensity profiles along the post discharge were obtained for selected vibrational spectral bands of these spectral systems and changes in the vibrational distributions of upper electronic states of these spectral systems were determined.

The decaying plasma was studied by the optical emission spectroscopy. DC discharge created at 45 – 200 mA in Pyrex and Quartz tubes in flowing regime was used. The emission of three nitrogen spectral systems (1st and 2nd positive and 1st negative) were studied in time evolution for pressures of 500 – 5 000 Pa at two wall temperatures – ambient and liquid nitrogen (150 K inside the decaying plasma). Results showed that all three nitrogen systems (respectively N2(B, v), N2(C, v) and N2+(B, v) states as their origins) had their population maxima called pink-afterglow in the afterglow part. These maxima decreased with the increase of pressure for all systems, and moved to the later decay time. Maxima increased with discharge current (respectively power) and moved to shorter time. Populations at temperature of 150 K were measured due to the experimental arrangement from 17 ms, only, and thus pink aftergow maximum wasn’t observed (only at 5 000 Pa some maximum was recognized). Populations were smaller at 150 K that populations measured at laboratory temperature at the middle decay time (50-100 ms). At the late time, the populations were higher at lower temperature at lower pressure. Higher shifts (in intensity and decaytime) of pink afterglow maxima were observed in Quartz tube in comparison with their values in Pyrex tube. Besides the populations, rotational temperatures of selected bands of three observed spetral systems (for 1st negative 0-0 band, 1st positive 2-0 band and for 2nd positive 0-2 band) were measured. Rotational temperatures were monitored from presumption that this kind of temperature is equal to temperature of neutral gas (at local thermodynamic equilibrium). Results from 1st negative and 1st positive system showed strong decreasing of rotational temperatures up to about 10 ms at post-discharge begin, then temperatures were constant up to 20 ms of decay time and after that they grew up. Temperatures increased with the increase of current. The part with decreased temperature correlated with pink-afterglow part of post-discharge. Unfortunately, rotational temperatures of 2nd positive system had bad reproducibility and the time profile shape was opposite. Experimental results were compared with numerical kinetic model created by group of prof. Vasco Guerra at Instituto Supetior Técnico in Portugal. Several sets of conditions for simulation at 500 and 1 000 K in active discharge were applicable for the calculation corresponding to the experiment. Comparison of numerical simulation and experimental data done for N2(B) state demonstrated that maxima populations in pink afterglow are depended on the temperature difference between active discharge and post discharge. Maxima populations were supposed in pink afterglow disappeared if the same temperatures in active and post discharges were supposed. Temperature in active discharge is higher at higher apllied power, as it was showed from rotational temperatures observation. The results clearly showed that real temperature profile must be included into the kinetic model.

Presented thesis gives results obtained during the spectroscopic observations of post –discharges of the pure nitrogen plasma with small oxygen admixture and in the nitrogen – argon mixture and the effect of the pink afterglow in it. The DC discharge in the flowing regime has been used for the plasma generation. The decaying plasma was study by optical emission spectroscopy, mainly in the range of 300–800 nm. The first positive, second positive, first negative nitrogen spectral system and NO spectral systems were observed in measured spectra. The band head intensities of these bands have been studied in the dependencies on experimental conditions. Simultaneously, the relative vibrational populations on the given nitrogen states have been calculated. Two discharge tubes made from different materials (PYREX glass and QUARTZ glass) were used in the case of nitrogen plasma containing low oxygen traces (up to 0.2 %). These experiments have been carried out at two wall temperatures for the determination of the temperature effect on the post-discharge. The discharge tube around the observation point was kept at the ambient temperature (300 K) or it was cooled down to 77 K by liquid nitrogen vapor. The total gas pressure of 1 000 Pa and the discharge current of 200 mA were conserved for all these experiments. The relative populations of electronic states were calculated in the dependence on the post-discharge time. The dependencies on oxygen concentration were given, too. The results showed no simple dependence of vibrational populations on oxygen concentration. Generally, slight increase of neutral nitrogen states populations was observed with the increase of oxygen concentration. These observations were well visible due to the intensity of nitrogen pink afterglow effect that was well visible at all oxygen concentrations. The pink afterglow maximal intensity was reached at about 5–10 ms at the wall temperature of 300 K in the PYREX tube. The molecular ion emission was strongly quenched by the oxygen and as this was dominant process for the pink afterglow emission the pink afterglow effect disappears at oxygen concentration of about 2000 ppm. The temperature and wall material influences were observed, too. The post-discharge in nitrogen argon mixtures was studied only in the PYREX tube at the ambient wall temperature of 300 K. The power dissipated in an active discharge was constant of 290 kW. The experimental studies had two new parameters – total gas pressure (500 Pa – 5 000 Pa) and the argon concentrations that were varied in the range of 0–83 %. Also in this case the dependencies of relative intensities of the bands given above were obtained and further the relative populations of electronic states as a function of decay time, total gas pressure and on argon concentration were obtained. The pink afterglow effect was observed at all applied discharge powers and total gas pressures. At the highest argon concentrations, especially at lower pressure, the pink afterglow effect disappeared. The presented experimental work is one of the hugest sets of experiments in the nitrogen with oxygen traces and in nitrogen-argon mixtures. These data can be used as a very good fundament for the further studies using wide numeric modeling of the post-discharge kinetic processes.

Million-gallon double-shell tanks at Hanford are used to store transuranic, high-level, and low-level radioactive wastes. These wastes consist of a large volume of salt-laden solution covering a smaller volume of settled sludge primarily containing metal hydroxides. These wastes will be retrieved and processed into immobile waste forms suitable for permanent disposal. Retrieval is an important step in implementing these disposal scenarios. The retrieval concept evaluated is to use submerged dual-nozzle jet mixer pumps with horizontally oriented nozzles located near the tank floor that produce horizontal jets of fluid to mobilize the settled solids. The mixer pumps are oscillated through 180° about a vertical axis so the high velocity fluid jets sweep across the floor of the tank. After the solids are mobilized, the pumps will continue to operate at a reduced flow rate producing lower velocity jets sufficient to maintain the particles in a uniform suspension (concentration uniformity). Several types of waste and tank configurations exist at Hanford. The jet mixer pump systems and operating conditions required to mobilize sludge and maintain slurry uniformity will be a function of the waste type and tank configuration. The focus of this work was to conduct a 1/12-scale experiment to develop an analytical model to relate slurry uniformity to tank and mixer pump configurations, operating conditions, and sludge properties. This experimental study evaluated concentration uniformity in a 1/12-scale experiment varying the Reynolds number (Re), Froude number (Fr), and gravitational settling parameter (Gs) space. Simulant physical properties were chosen to obtain the required Re and Gs where Re and Gs were varied by adjusting the kinematic viscosity and mean particle diameter, respectively. Test conditions were achieved by scaling the jet nozzle exit velocity in a 75-in. diameter tank using a mock-up of a centrally located dual-opposed jet mixer pump located just above the tank floor. Concentration measurements at sampling locations throughout the tank were used to assess the degree of uniformity achieved during each test. Concentration data was obtained using a real time in-situ ultrasonic attenuation probe and post-test analysis of discrete batch samples. The undissolved solids concentration at these locations was analyzed to determine whether the tank contents were uniform (≤ ±10% variation about mean) or nonuniform (> ±10% variation about mean) in concentration. Concentration inhomogeneity was modeled as a function of dimensionless parameters. The parameters that best describe the maximum solids volume fraction that can be suspended were found to be 1) the Fr based on nozzle average discharge velocity and tank contents level and 2) the dimensionless particle size based on nozzle diameter. The dependence on the jet Re does not appear to be statistically significant.