Homogeneous Tank Research Articles

Medidas de control de olores para un tanque homogeneizador de una planta de tratamiento de aguas residuales en Costa Rica

[Objective] This study aimed to evaluate the short-term response of four different odor control measures in a homogenization tank of a university Wastewater Treatment Plant (WWTP). [Methodology] The following were implemented: aeration, adding lime, adding iron sulfate, and adding the commercial product BiOWiSH® Odor over four hydraulic retention times. The effluent and the unit were monitored during each period, using a baseline to compare the measures. Hydrogen potential, oxidation-reduction potential, dissolved oxygen, and dissolved sulfide concentration were measured in triplicate every 30 minutes. An odor perception survey was administered to WWTP visitors to evaluate intensity, offensiveness, and character (15 surveys per monitoring period). Differences were determined between control measures and the baseline using Student’s t-tests (quantitative data) and Mood’s median tests (qualitative data). Minitab 2019 was used with a 95% confidence level. [Results] All control measures significantly reduced the dissolved sulfide concentration in the unit. Aeration prevented oxygen depletion, reductive regime, and acid fermentation, which favored the oxidation of odorants. Aeration was also the only studied control measure that reduced odor intensity and offensiveness. [Conclusions] Applying aeration changed unit behavior and odor perception, which confirms its effectiveness, while adding iron sulfate, lime, and BiOWiSH® did not significantly change odor perception.

Degradation of Dyes in Real Textile Industry Wastewater Samples by Fenton Process

This research proposes a solution to the problem of industrial safety and the improvement of environmental processes in the textile industry through the degradation of dyes from its processes using the Fenton reaction. This advanced oxidation technology makes it possible to reduce the possible environmental impacts caused by the organic matter generated in industrial activity. Sampling was conducted under real operating conditions in the homogenization tank of the Industrias Printex SAS wastewater treatment plant. Advanced oxidation was carried out applying the Fenton process using iron from ferrous sulfate heptahydrate as a catalyst and hydrogen peroxide at different concentrations in a 6-post flocculator. Among the results obtained, an optimal dose of 571 ppm of iron and 38 ppm of hydrogen peroxide was found through statistical analysis with the STATGRAPHICS program using the 2k factorial design and constructing response surfaces. A comparative study between the Fenton treatments, treatment with hydrogen peroxide, and treatment with ferrous sulfate heptahydrate showed the Fenton reaction at neutral pH, attributed to the presence of some organic acids such as citric acid, used as a chelating agent (Fenton modified). The proposed treatment was compared with the one that uses chlorine, applying it in three (3) different tanks through a multifactorial ANOVA with the data collected when scaling the treatment, finding that the proposed Fenton treatment is more efficient. This research was innovative because it demonstrated the feasibility of scaling up the Fenton process to neutral pH in a textile wastewater treatment plant, reducing operating costs and minimizing environmental impact.

Monte-Carlo dose computation in radiotherapy for lung at very low density

Introduction In radiotherapy, some limits of clinical algorithms have been reported in low-density media. When patients are treated during Deep Inspiration Breath-Hold (DIBH), lung density can fall to 0.12 g cm -3 . Dose calculation with this density must be validated, in particular for Stereotactic (SBRT) treatment. Purpose We propose to evaluate the performance of Eclipse AAA algorithm (Varian) for SBRT lung treatment (including DIBH) with a Monte-Carlo model based on Geant4 (GATE). GATE, AAA, and measurements are compared for several phantoms including lung heterogeneity. Materials and methods A model of the Varian TrueBeam head was modelled using GATE. Validation was achieved by comparison with measurements in a homogeneous water tank for several static fields (3 × 3 to 20 × 20 cm 2 ) and four beam modes. Subsequently, two phantoms containing layers of water-equivalent material and cork, corresponding to lung during DIBH and free-breathing (0.12 and 0.24 g cm -3 ) were implemented. Percentage depth dose (PDD) measured by Gafchromic films were compared to AAA and GATE. Results GATE model showed a good agreement with experimental results in homogeneous and heterogeneous phantoms. In lung heterogeneity, differences were observed between AAA and measurements. These differences are higher for small fields and lower densities. As an example, for 3 × 3 field size inside a 0.12 g cm -3 heterogeneity, relative dose was 56,6%, 56,2%, and 67,5% for measurement, GATE, and AAA respectively. Conclusions In very low densities, AAA quickly showed its limits while GATE was validated. This will allow us to perform calculations for non measurable cases, for example patients treated by SBRT during DIBH.

Propuesta de un estimador de fallas usando fracciones coprimas

Los sistemas de detección, diagnóstico y aislamiento de fallas (FDDI), generan señales (residuos) que contienen detalles de la falla. La estimación de estado es un procedimiento común para la generación de residuos cuando se usa redundancia analítica. En este artículo, la hipótesis propuesta es usar la teoría de fracciones coprimas para generar un estimador de salida; este compite con algunos estimadores clásicos como Kalman, Luemberger, Lyapunov y Jordan, con ellos se analizan los tiempos de ejecución y tasas de precisión en la estimación usando el error medio cuadrático en presencia de fallas aditivas. Los resultados son validados sobre un sistema FDDI implementado sobre un tanque de homogenización en lazo cerrado usando el estándar para control de procesos OPC y simulando físicamente una falla en el sensor RTD de salida

Energy 360: Invited Perspective: Reservoir Modeling Today and Tomorrow

President's column Reservoir performance forecasting is still the “Grand Central Station” of all the exploration and production (E&P) disciplines because this is where everything (the large-scale reservoir plumbing system, reservoir properties, fluid properties, wells, completions, lift curves/hydraulics, facilities, fluid handling capacities, and much more) is integrated and comes together in a life-of-field forecast. The revenue from the field development is the composite oil and gas production rates into the future multiplied by the forward oil and gas prices. The reservoir description, which I call the “subsurface plumbing system,” in a forecasting model can range from a simple homogeneous analytical tank model to an unbelievably complex dual porosity, compositional simulation model with one billion grid cells, pseudos ( from endless upscaling), and many other sophisticated features built in to try to mimic a very complex reality. I had the opportunity to discuss the state of the art and the future of reservoir modeling and reservoir performance forecasting with one of the finest members of the reservoir engineering profession, professor Larry W. Lake, of the University of Texas at Austin (UT). You have taught reservoir modeling to undergraduates and graduate students for more than 30 years. How has the reservoir modeling discipline evolved? The biggest evolution has been caused by the capacity of computers. The capacity has allowed combinations of traditional simulation with facilities, improved resolution of heterogeneity, progress in automated history matching, and uncertainty estimation to name just a few. In order for universities such as UT to understand the main reservoir modeling challenges of the E&P industry, close collaboration and a dialogue on real industry needs must happen. What is your view of the state of industry/academia collaboration? Are you collaborating more with service companies than with international oil companies, national oil companies, and independents? We at UT do well in the collaboration department and on all the major avenues of E&P. The challenge for us is the boundary between technology development and research. We do, or at least we should do, research.

Simulation model of the technological complex of charge preparation for sinter production

A simulation model of the technological complex of charge preparation for sinter production was developed. This approach stems from the fact that the dimension of tasks and non-formalizability of objects do not allow to use rigorous mathematical methods. Integrated debugging and testing of the system on the real object is impossible without the simulation model considering the insecurity of the artificial creation of emergency situations. Using the developed simulation model, the factors, affecting the charge quality stabilization were investigated. It was proposed to build a domain model using ontology that allows to avoid contradictions in determining the type of the class hierarchy. Also, it was proposed to use the original identification procedure of weighted average values of the content of chemical elements and oxides in the homogenization tank, as well as the multiagent approach for simulating emergency situations. As a result of the research, it was found that the characteristics of the formed stack from various types of disruptions in the homogenization unit. Estimates of trends in the monitored parameters at the homogenization unit synchronization failures were obtained, and contributions of the change of technological processes to the occurrence and magnitude of the anomalous zones in the stack were defined. Using the resulting model allows to solve the stack formation management problem.

Treatment of dairy industry wastewater by oxygen injection: performance and outlay parameters from the full scale implementation

This work presents the application of a new system for wastewater treatment in the food industry, which is based in the injection of pure oxygen in the homogenization tank of a traditional physicochemical treatment. This system operates stably under a wide variety of both input chemical oxygen demand (COD) and total suspended solids (TSS). Compared with the previous physicochemical system, it has been proved that the new one is more efficient and implies important economic savings for the dairy. Compared with a traditional anaerobic treatment, it has been shown that the oxygen injection system avoids the relatively high costs associated to the initial investment and operating costs and is environmentally friendlier. In this work it is shown that oxygen injection may be an interesting option for the dairy industry wastewater treatment.

Denitrification Enzyme Activity in Swine Wastewater Effluent of a Nitrification/Denitrification Treatment System

Intensification of swine production in the U.S. and around the world requires advanced manure management. For swine manure management in the state of North Carolina, one system met all of the required advanced management criteria, and it was qualified as an environmentally superior technology. This investigation was part of the testing for this superior technology. The objectives of this investigation were to assess: (1) the denitrification enzyme activity (DEA) in the treatment systems homogenization tank and denitrification tank, and (2) the impact of the wastewater characteristics on this DEA. The DEA was measured by the acetylene inhibition method. Wastewater in the homogenization tank was fresh-flushed directly from the swine houses. Consequently, it was more concentrated than wastewaters in either the denitrification tank or typical swine wastewater lagoons; it had soluble biochemical oxygen demand (sBOD) of 676 mg L-1 and an electrical conductivity (EC) of 8.9 mS cm-1. However, the DEA in the homogenization tank was significantly limited by the low level of NO3-N, which was 0.1 mg L-1. Conversely, the DEA of the denitrification tank was limited by its lower level of carbon; it had only 53 mg L-1 sBOD. However, it had a NO3-N concentration of 150 mg L-1. When non-limiting glucose-C and NO3-N were added to the wastewaters of the homogenization and denitrification tanks, the homogenization tank had a significantly higher level of potential DEA: 17,943 vs. 10,055 mg N2O-N m-3 d-1, respectively. The DEA was generally well correlated by stepwise regression to the measured physiochemical characteristics. The findings of this investigation document that the DEA within this treated swine wastewater can be altered by manageable constituents of the processed swine wastewater, in particular soluble carbon and oxidized nitrogen.

Evaluation of a biologically-based filtration water reclamation plant for removing emerging contaminants: A pilot plant study

The effect of hydraulic retention time (HRT), solar radiation and seasonality on the removal efficiency of 18 emerging contaminants has been studied in a biological filtration pilot plant based on Daphnia sp. The pilot plant consisted of a homogenization tank and two lines, A and B, each with four 1m3 tanks. One of these lines was directly exposed to sunlight whereas the other line was covered. Our results suggest that biodegradation and photodegradation are the most important removal pathways, whereas sorption makes a minor contribution. The removal efficiency ranged from no detectable removal to more than 90%. The kinetics of the degradation process was fit to a first order kinetic, with half-lives from 0.6 to 42days, depending on the particular compound. However, a scaling effect comes into play as the pilot plant was found to be more efficient than a similar full-scale polishing pond.

Electrode boundary conditions and experimental validation for BEM-based EIT forward and inverse solutions

In this paper, we present theoretical developments and experimental results for the problem of estimating the conductivity map inside a volume using electrical impedance tomography (EIT) when the boundary locations of any internal inhomogeneities are known. We describe boundary element method (BEM) implementations of advanced electrode models for the forward problem of EIT. We then use them in the inverse problem with known internal boundaries and derive the associated Jacobians. We report on the results of two EIT phantom studies, one using a homogeneous cubical tank, and one using a cylindrical tank with agar conductivity inhomogeneities. We test both the accuracy of our BEM forward model, including the electrode models, as well as our inverse solution, against the measured data. Results show good agreement between measured values and both forward-computed tank voltages and inverse-computed conductivities; for instance, in a phantom experiment, we reconstructed the conductivities of three agar objects inside a cylindrical tank with an error less than 2% of their true value.

SOLID-LIQUID SEPARATION OF SWINE MANURE WITH POLYMER TREATMENT AND SAND FILTRATION

Small particles typical of liquid swine manure often clog sand filter beds and fine filters. We evaluated the effectiveness of polymer flocculants to improve drainage and filtration performance of sand filter beds by increasing the particle size of manure. A pilot separation unit was evaluated at the Swine Unit of the NCSU Lake Wheeler Road Laboratory in Raleigh, North Carolina, in 40 consecutive cycles during a 20-month period. The unit consisted of a homogenization tank that mixed the flushed swine manure, an in-line polymer mixer, and two sand filter beds (29.7 m2) designed to receive 30.5 cm (1 ft) depth of the polymer-treated effluent. Flocculation treatment using polyacrylamide (PAM) polymer improved drainage characteristics of the sand filter by preventing clogging and surface sealing. The combination of flocculation and filtration treatment removed 97% of total suspended solids (TSS) and volatile suspended solids (VSS), 85% of biochemical oxygen demand (BOD5), and 83% of chemical oxygen demand (COD) from the flushed manure. Along with the solids, treatment resulted in capture of 61% total Kjeldahl nitrogen (TKN) and 72% total phosphorus (TP). Most of the nutrients removed in the solids were organic forms. Drying time to produce removable cakes varied significantly with the loading rate of solids applied to the sand filter bed. A load of <2 kg TSS m-2 per drying cycle allowed completion of the drying cycle in about 8 days, which is desirable to reduce potential fly problems. Our results indicate that PAM flocculation enhances performance of dewatering sand filter beds for swine manure applications.

Integrated Geologic and Engineering Reservoir Characterization of the Hutton Sandstone, Jackson Region, Australia: ABSTRACT

An integrated geologic and engineering reservoir characterization study of the Hutton Sandstone was completed for the Jackson region, Eromanga Basin, Australia. Our approach involves four principal steps: (1) determine reservoir architecture within a high-resolution sequence stratigraphic framework, (2) investigate trends in reservoir fluid flow, (3) integrate fluid flow trends with reservoir architecture to identify fundamental reservoir heterogeneities, and (4) identify opportunities for reserve growth. Contrary to the existing perception, the Hutton Sandstone, a continental-scale bed-load fluvial system, does not behave as a large, homogeneous tank in which pistonlike displacement of produced oil occurs unimpeded by vertical migration of the aquifer. The sequence stratigraphic analysis identified numerous thin but widespread shale units, deposited during lacustrine flooding events that periodically interrupted episodes of coarse clastic Hutton deposition. These shales represent chronostratigraphically significant surfaces. More importantly, the trends established in reservoir fluid flow from monitoring aquifer encroachment, production response to water shut-off workovers, and differential depletion in Repeat Formation Tests indicate that these shale units act as efficient barriers to vertical fluid flow. Erosion of the upper part of the Hutton reservoir by the younger Birkhead mixed-load fluvial system caused further stratigraphic complexity and introduced additional barriers to vertical and lateral migration ofmore » mobile oil and aquifer encroachment. This integrated characterization targeted strategic infill and step-out drilling and recompletion candidates.« less

Modelling of condensation polymerization of novolac‐type phenol–formaldehyde in homogeneous, continuous‐flow, stirred‐tank reactors

AbstractA detailed kinetic model for the novolac‐type phenol–formaldehyde polymerization has been proposed in terms of five reactive sites. These sites have been shown to have different reactivities. Mass‐balance equations for homogeneous, continuous‐flow, stirred tank reactors (HCSTR) for each of the species have been written, and these have been solved numerically. A comparison of the results with those for the batch reactor shows that, for a given residence time, smaller but more polydispersed and branched chains are formed.