scholarly journals INFLUENCE OF THE SIDE VENTILATION ON THE DURABILITY OF THE FUNCTIONING OF DRYING BEDS WITH NON-SATURATED FLOW IN TREATEMENT OF SEPTIC TANK SLUDGE

2021 ◽  
Vol 9 (06) ◽  
pp. 172-186
Author(s):  
Yeo Tenena Martial ◽  
◽  
Kone Kinanpara ◽  
Bony Kotchi Yves ◽  
Kouame Yao Francis ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Lateral Surface ◽  
Large Scale ◽  
Flow Model ◽  
Side Surface ◽  
Organic Load ◽  
Septic Tank ◽  
Saturated Flow ◽  
Efficient Treatment ◽  
Purification Efficiency

The non-saturated Flow Drying Beds allow efficient treatment of septic tank sludge. However, they are vulnerable to clogging. To ensure the sustainability of this technology, through an additional supply of oxygen from the lateral surface, a flow model coupled with the variation of the biofilm has been developed. The calibration, validation and comparison of the simulated and experimental results were made from the NASH criterion. The simulations focused on two types of reactors. A reactor with pores on its side surface is called a ventilated reactor (VR). The second is then called an unventilated reactor (UVR). The results show that the maximum applicable organic load is 43.3 mgO2 / cm2 / d at the UVR level and 51.8 mgO2 / cm2 / d at the VR level. In addition, the reduction in free flow porosity is 93.33% at the UVR level and 81% at the AR level. In addition, the results show that when the hydraulic head is less than 5 cm / d, the COD removal efficiency is 96.19% at the UVR level and 95.64% at the VR level. But, when the load is greater than 5 cm / d, the yield is 92.65% at the level of the UVR and of 94.95% at the level of the VR. Thus, in the context of a large-scale operation, lateral ventilation is essential. It guarantees good purification efficiency, slows down internal clogging of beds and accelerates its reversibility when it occurs.

High Efficient Treatment of Coal Gasification Wastewater by Precipitation and Photocatalysis Process

2014 ◽  
Vol 997 ◽  
pp. 749-753
Author(s):  
Mao Xiang Jing ◽  
Chong Han ◽  
Xiang Qian Shen
Keyword(s):  
Removal Efficiency ◽  
Large Scale ◽  
Coal Gasification ◽  
High Efficiency ◽  
Ph Value ◽  
Ammonium Phosphate ◽  
Magnesium Ammonium Phosphate ◽  
Efficient Treatment ◽  
High Efficient ◽  
Coal Gasification Wastewater

This study was conducted to investigate a novel treatment method for coal gasification wastewater (CGWW) by combining magnesium ammonium phosphate (MAP) precipitation and photocatalysis processes. The optimized conditions for MAP process were explored, and the removal efficiency of NH4-N by the MAP treatment can exceed 85% at the mole ratio of 1.2~1.4 MgCl2 and 0.9 Na2HPO4 to NH4+ as precipitators, and the pH value at 9.0~9.5. The MAP precipitates are an useful slow-available-fertilizer. After the photocatalysis treatment of 5hrs, the total removal efficiency for NH4-N, COD, Phenol and CN− exceeds 99%, 95%,90% and 90%,respectively.This technology with low cost and high efficiency has big potential to treat CGWW practically on a large scale.

Effects of hydraulic shock loads on small on-site sewage treatment unit

1997 ◽  
Vol 35 (8) ◽  
pp. 145-152 ◽  
Author(s):  
T. Panswad ◽  
L. Komolmethee
Keyword(s):  
Removal Efficiency ◽  
Sewage Treatment ◽  
Septic Tank ◽  
Hydraulic Shock ◽  
Treatment Unit ◽  
Shock Loads ◽  
Retention Period ◽  
Intermittent Feeding ◽  
Continuous Feed ◽  
Filter Unit

This research was to determine the effects of hydraulic shock loads by intermittent feeding on the removal efficiency of a small prefabricated real-sized septic tank/anaerobic filter unit. Besides the ‘control’ 24-hour continuous runs the other twice a day feeding periods covered 16, 12 and 8 hours per day, with the tank's retention time varying from 22.5 to 90 hours. It was demonstrated that the variation of the hydraulic feeding patterns ranging from 24-hour continuous feed to 8 h per day intermittent feed did not affect the performance of the system much. The percentage of BOD reduction was decreased from 85 to 82 and 81 percent for the feed times of 24, 16 and 8 hours per day, respectively. The tank capacity played a relatively major role in determining the removal efficiency of the process. The efficiency of BOD and SS reduction dwindled from 82.2 to 68.9 and 56.0% with the corresponding reduction in tank sizes from 90 to 45 and 22.5 hours retention, respectively. In any event, the unit could not satisfactorily remove nutrients. A retention period of not less than 48 hours is recommended if the Thai effluent standards are to be met. Equations for predicting the BOD removal capability were also developed.

scholarly journals Investigation of Heavy Metal Effects on the Anaerobic Co-Digestion Process of Waste Activated Sludge and Septic Tank Sludge

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Quang-Minh Nguyen ◽  
Duy-Cam Bui ◽  
Thao Phuong ◽  
Van-Huong Doan ◽  
Thi-Nham Nguyen ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Activated Sludge ◽  
Removal Efficiency ◽  
Biogas Production ◽  
Cod Removal ◽  
Septic Tank ◽  
Waste Activated Sludge ◽  
Digestion Process ◽  
Cod Removal Efficiency

The effect of copper, zinc, chromium, and lead on the anaerobic co-digestion of waste activated sludge and septic tank sludge in Hanoi was studied in the fermentation tests by investigating the substrate degradation, biogas production, and process stability at the mesophilic fermentation. The tested heavy metals were in a range of concentrations between 19 and 80 ppm. After the anaerobic tests, the TS, VS, and COD removal efficiency was 4.12%, 9.01%, and 23.78% for the Cu(II) added sample. Similarly, the efficiencies of the Zn(II) sample were 1.71%, 13.87%, and 16.1% and Cr(VI) efficiencies were 15.28%, 6.6%, and 18.65%, while the TS, VS, and COD removal efficiency of the Pb(II) added sample was recorded at 16.1%, 17.66%, and 16.03% at the concentration of 80 ppm, respectively. Therefore, the biogas yield also decreased by 36.33%, 31.64%, 31.64%, and 30.60% for Cu(II), Zn(II), Cr(VI), and Pb(II) at the concentration of 80 ppm, compared to the raw sample, respectively. These results indicated that Cu(II) had more inhibiting effect on the anaerobic digestion of the sludge mixture than Zn(II), Cr(VI), and Pb(II). The relative toxicity of these heavy metals to the co-digestion process was as follows: Cu (the most toxic) > Zn > Cr > Pb (the least toxic). The anaerobic co-digestion process was inhibited at high heavy metal concentration, which resulted in decreased removal of organic substances and produced biogas.

scholarly journals Evaluation of wet air oxidation variables for removal of organophosphorus pesticide malathion using Box-Behnken design

2016 ◽  
Vol 75 (3) ◽  
pp. 619-628 ◽  
Author(s):  
Melike Isgoren ◽  
Erhan Gengec ◽  
Sevil Veli
Keyword(s):  
Removal Efficiency ◽  
Applied Pressure ◽  
Organophosphorus Pesticide ◽  
Operating Conditions ◽  
Quadratic Model ◽  
Air Oxidation ◽  
Wet Air Oxidation ◽  
Reaction Conditions ◽  
Efficient Treatment ◽  
Optimum Reaction

This paper deals with finding optimum reaction conditions for wet air oxidation (WAO) of malathion aqueous solution, by Response Surface Methodology. Reaction conditions, which affect the removal efficiencies most during the non-catalytic WAO system, are: temperature (60–120 °C), applied pressure (20–40 bar), the pH value (3–7), and reaction time (0–120 min). Those were chosen as independent parameters of the model. The interactions between parameters were evaluated by Box-Behnken and the quadratic model fitted very well with the experimental data (29 runs). A higher value of R2 and adjusted R2 (>0.91) demonstrated that the model could explain the results successfully. As a result, optimum removal efficiency (97.8%) was obtained at pH 5, 20 bars of pressure, 116 °C, and 96 min. These results showed that Box–Behnken is a suitable design to optimize operating conditions and removal efficiency for non-catalytic WAO process. The EC20 value of raw wastewater was measured as 35.40% for malathion (20 mg/L). After the treatment, no toxicity was observed at the optimum reaction conditions. The results show that the WAO is an efficient treatment system for malathion degradation and has the ability of converting malathion to the non-toxic forms.

The Removal of Impurity Silicon from Aluminum Melt by the Addition of K2TiF6

2017 ◽  
Vol 748 ◽  
pp. 192-196 ◽  
Author(s):  
Guo Liang Zhu ◽  
Rui Wang ◽  
Wei Wang ◽  
Da Shu ◽  
An Ping Dong ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Silicon Concentration ◽  
Aluminum Melt ◽  
Purification Efficiency ◽  
Initial Silicon ◽  
Novel Method ◽  
Holding Temperature

A novel method to remove impurity silicon from aluminum melt by the addition of K2TiF6 was studied. The mechanism for silicon removal is the formation and sedimentation of Ti(Al1-x,Six)3 phase and the removal efficiency is mostly decided by the solubility of silicon in TiAl3 phase, which increases with the increasing of the initial silicon concentration in aluminum melt. The effect of holding temperature on the impurity Si purification efficiency was investigated and the result indicated that the effect of holding temperature is very finite.

Modelling present and future Po river interactions with alluvial aquifers (Low Po River Plain, Italy)

2014 ◽  
Vol 5 (3) ◽  
pp. 457-471 ◽  
Author(s):  
M. Mastrocicco ◽  
N. Colombani ◽  
A. Gargini
Keyword(s):  
Groundwater Flow ◽  
Large Scale ◽  
Flow Model ◽  
Transient Flow ◽  
Scale Model ◽  
Groundwater Flow Model ◽  
Po River ◽  
Local Conditions ◽  
Aquifer System ◽  
Hydrological Conditions

A modelling study on a multi-layered confined/unconfined alluvial aquifer system was performed to quantify surface water/groundwater interactions. The calibrated groundwater flow model was used to forecast climate change impacts by implementing the results of a downscaled A1B model ensemble for the Po river valley. The modelled area is located in the north-western portion of the Ferrara Province (Northern Italy), along the eastern bank of the Po river. The modelling procedure started with a large scale steady state model followed by a transient flow model for the central portion of the domain, where a telescopic mesh refinement was applied. The calibration performance of both models was satisfactory, in both drought and flooding conditions. Subsequently, forecasted rainfall, evapotranspiration and Po river stage at 2050, were implemented in the calibrated large scale groundwater flow model and their uncertainties discussed. Three scenarios were run on the large scale model: the first simulating mean hydrological conditions and the other two simulating one standard deviation above and below the mean hydrological conditions. The forecasted variations in groundwater/Po river fluxes are relevant, with a general increase of groundwater levels due to local conditions, although there are large uncertainties in the predicted variables.

scholarly journals Effect of growth hormone and growth media on the rooting and shooting of Zanthoxylum armatum stem cuttings

2018 ◽  
Vol 28 (2) ◽  
pp. 3-12
Author(s):  
N. Phuyal ◽  
P. K. Jha ◽  
P. P. Raturi ◽  
S. Gurung ◽  
S. Rajbhandary
Keyword(s):  
Root Length ◽  
Large Scale ◽  
Growth Media ◽  
Naphthalene Acetic Acid ◽  
Scale Production ◽  
Stem Cuttings ◽  
Efficient Treatment ◽  
Zanthoxylum Armatum ◽  
Significant Difference ◽  
Rooting Media

The common method of propagation is through seeds but seed germination in Zanthoxylum armatum is very low due to the presence of hard seed coat, which might be a great hurdle for large scale production of plantlets. So an attempt was made in this study to see the effect of different growth hormones, their concentrations and different rooting media on the rooting and sprouting of Z. armatum. The stem cuttings of Z. armatum were treated with two types of auxins namely Indole-3-Butyric Acid (IBA) and Naphthalene Acetic Acid (NAA) at different concentrations (2000 ppm, 3000 ppm and 5000 ppm), while the untreated cuttings were used as control. The cuttings were planted in three different rooting media: sand, neopeat and mix (containing a mixture of sand, soil and vermin-compost). The completely randomized design was used for the experiment. The total number of stem cuttings of Z. armatum used in the experiment was 1080 for 18 treatments in three replicates (20 cuttings per treatment x 18 treatments x 3 replicates). The experiment was set up in controlled greenhouse conditions at Dabur Nepal Private Limited Nursery, Banepa, Kavre District. The parameters evaluated were root length, shoot length and number of roots per cutting. The collected data were analyzed statistically using R-program with Agricola. Least significant difference (LSD) and Duncan multiple Range Test (DMRT), as mean separation technique was applied to identify the most efficient treatment in the rooting and shooting behavior of Z. armatum (Gomez and Gomez, 1984). Hormone concentration and growth media significantly affected the rooting and shooting ability of Z. armatum stem cuttings. IBA was found to be more effective than NAA. Neopeat medium was better than sand and mix media. The highest number of roots (6.5) and root length (11.6 cm) were recorded under IBA 5000 ppm in neopeat medium.

scholarly journals Data work: A condition for integrations in health care

2019 ◽  
Vol 25 (3) ◽  
pp. 526-535 ◽  
Author(s):  
Camilla Bjørnstad ◽  
Gunnar Ellingsen
Keyword(s):  
Health Care ◽  
Large Scale ◽  
Health Care Systems ◽  
Medication Management ◽  
Articulation Work ◽  
Efficient Treatment ◽  
Daily Work ◽  
Local Actors ◽  
Care Systems ◽  
Information And Communication

Integration and interoperability between different information and communication technology (ICT) systems are crucial for efficient treatment and care in hospitals. In this article, we are particularly interested in the daily local work conducted by health-care personnel to maintain integrations. A principal aim of our article is, therefore, to contribute to a sociotechnical understanding of the “data work” that is embedded in the integration of health-care systems. Theoretically, we draw on the concepts of “information infrastructures” and “articulation work,” and we discuss how social status may influence the invisible articulation work. Furthermore, we show how historical decisions and existing systems both nationally and regionally have impacts on the daily work of local actors. Empirically, we have studied the formative stages of a large-scale electronic medication management system project in the Northern Norway Regional Health Authority.

scholarly journals Importance of Magnetic Effects in a Two-Flow Model for Extragalactic Radio Jets

1990 ◽  
Vol 140 ◽  
pp. 445-445
Author(s):  
H. Sol ◽  
G. Pelletier ◽  
E. Asseo
Keyword(s):  
Magnetic Field ◽  
Coming Out ◽  
Large Scale ◽  
Flow Model ◽  
Minimal Distance ◽  
Relativistic Electrons ◽  
Ambient Plasma ◽  
Relaxation Zone ◽  
Radio Jets ◽  
The Magnetic Field

We propose a model for extragalactic radio jets in which two different flows of particles are taken into account, (i) a beam of relativistic electrons and positrons extracted from the funnel of accretion disc and responsible for the observed superluminal motion, (ii) a classical or mildly relativistic wind of electrons and protons coming out from all parts of the disc (Sol et al., 1989). Studying the mutual interaction of the two flows, we show that the configuration is not destroyed by the plasma-beam instability as long as the magnetic field, assumed longitudinal, is strong enough, with an electron gyrofrequency ωc = eB/mec greater than the ambient plasma frequency ωp = (4πnpe2)1/2 (Pelletier et al., 1988). When ωc < ωp, the relativistic beam loses its energy and its momentum mainly through the development of strong Langmuir turbulence in the wind, and disappears quietly after some relaxation zone where heating and entrainment of the wind occur. This emphasizes one aspect of the important role likely played by the magnetic field in the dynamics of extragalactic jets and provides one example in which the magnetic field, acting on the microscopic scale of an interaction, induces strong effects on large–scale structures. Detailed data on the closest known superluminal radio source 3C120 (Walker et al., 1987, 1988; Benson et al., 1988) allow a check on the likelihood of our model. Observational estimates of the variation along the jet of the magnetic field and of the ambient plasma density np suggest that the magnetic field reaches its critical value (corresponding to ωc = ωp) at a minimal distance of about 1.4 kpc from the central engine. This is amazingly close to the location of the 4′–radio knot, a “rather curious structure” described by Walker et al. (1987), which we interpret as the beam relaxation zone in the context of our two–flow model (Sol et al., 1989).

scholarly journals Accumulation patterns around Dome C, East Antarctica, in the last 73 kyr

2018 ◽  
Vol 12 (4) ◽  
pp. 1401-1414 ◽  
Author(s):  
Marie G. P. Cavitte ◽  
Frédéric Parrenin ◽  
Catherine Ritz ◽  
Duncan A. Young ◽  
Brice Van Liefferinge ◽  
...  
Keyword(s):  
Large Scale ◽  
Flow Model ◽  
East Antarctica ◽  
Small Scale ◽  
Time Interval ◽  
Accumulation Rates ◽  
Ice Flow ◽  
Last Glacial ◽  
Prevailing Wind Direction ◽  
The Last Glacial

Abstract. We reconstruct the pattern of surface accumulation in the region around Dome C, East Antarctica, since the last glacial. We use a set of 18 isochrones spanning all observable depths of the ice column, interpreted from various ice-penetrating radar surveys and a 1-D ice flow model to invert for accumulation rates in the region. The shallowest four isochrones are then used to calculate paleoaccumulation rates between isochrone pairs using a 1-D assumption where horizontal advection is negligible in the time interval of each layer. We observe that the large-scale (100s km) surface accumulation gradient is spatially stable through the last 73 kyr, which reflects current modeled and observed precipitation gradients in the region. We also observe small-scale (10 s km) accumulation variations linked to snow redistribution at the surface, due to changes in its slope and curvature in the prevailing wind direction that remain spatially stationary since the last glacial.

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