Sand Sludge Research Articles

Magneto-optical Properties of Iron-bulk Metallic Glasses Sustainably Produced from Iron-rich Sand Sludge

A large amount of sand sludge (SS) from rivers polluted with heavy metals is continuously dredged and often dumped into landfills, resulting in environmental pollution of soil and water. This work examines the feasibility of the utilization of iron-enriched SS from dredged polluted rivers to produce Fe-based bulk metallic glasses (Fe-BMG). Fe-BMG was prepared from SS by melt-quenching technique, and their magnetic and photochromic properties were studied. The chemical composition of the Fe-BMG was determined by X-ray fluorescence (XRF). The structural properties have been analyzed using the Raman spectroscopy (RS), vibrating sample magnetometer (VSM) and ultraviolet-visible (UV-VIS) spectroscopy. XRF results shows that Fe-BMG contains an iron proportion of 38.8% (wt.) as the hematite (\(\alpha\)-Fe2O3), and magnetite (Fe3O4) phases. The Raman “fingerprints” of \(\alpha\)-Fe2O3 and Fe3O4 were identified at 1330 cm−1, and 300-600 cm-1, respectively. The measured saturation magnetization of Fe-BMG samples is 3.0 emu/g at 60 kOe. A UV-VIS analysis of the Fe-BMG exposed to sunlight simulator reveals an enhanced transmission of light in the 400-700 cm-1 region. These findings confirmed the successful conversion of the hazardous SS into Fe-BMG with promising magneto-optical characteristics for a wide variety of technological applications.

Influence of Type of Secondary Raw Material on Consistency of Fresh Mixture for AAC Production

Autoclaved aerated concrete (AAC) is, mainly in Europe, widely used construction material. It has an optimal combination of bulk density, strength and thermal conductivity coefficient for load-bearing and non-load-bearing structures of civil facilities. The production technology is based on a mixture of ground silica sand, lime, cement, gypsum, aluminium powder and additives. The grinding of sand is most often carried out in a wet way, and the sand sludge is consequently used in production technology. The aim of the experiment was verification of the effect of partial replacement of sand with the alternative raw materials in sand sludge on the rheology of the mixture. This parameter determinates how the modified mixtures affect the sludge pumpability. As a reference the consistency of the sand sludge of the normal production density of 1.65 g/cm3 was compared to the sand sludges of different density (1.60, 1.70 and 1.75 g/cm3) and with a fresh aerated concrete (FAC) mixture of 1.60 g/cm3. Then the sludges were modified by 30 % of alternative raw materials (recycled glass, coal slag, FBC ash, FBC bottom ash) as the partial weight replacement for sand. This partial replacement resulted in water/solids ratio adjustment which recommended value is 0.47 for recycled glass and coal slag, 0.59 for fluidized bed combustion (FBC) bottom ash and for FBC fly ash it is 0.70.

A review on consolidation theories and its application

Compressibility of clays is mainly caused by expulsion of water between the soil grains and slipping of particles to new position to attain greater densities. Consolidation plays an important role in stability analysis for the embankment, footings or a column constructed on clayey soils. The settlement behaviour of these structures and the pore pressure needs to be investigated for construction on these soils. The consolidation problem has been formulated by many researchers by coupling the soil deformation and the pore pressure. Though stress-strain behaviour of soil is highly non-linear, initial works on consolidation analysis idealised soil as linearly elastic material. The behaviour of waste materials such as dredged materials, mine tailings, oil sand sludge and waste sludge is quite different than conventional soils as they experience very large deformations and changes in void ratio. The present paper reviews the various consolidation theories for soils and waste materials.

Analisis Kadar Logam Kadmium (Cd) dan Timbal (Pb) pada Sedimen Di Teluk Ambon Bagian Dalam

The research about analysis of cadmium (Cd) and lead (Pb) metal content on sediment inner part of Ambon Bay has been done. Sampling point located at Dermaga Ferry Poka, PLTD Poka, Kate-kate, Waiheru, Lateri III, Passo dan PLTD Galala. The results of analyzed of sediment particle size inside the Ambon Bay showed 3 components were sand, gravel, and sludge, but the sediments was dominated by sludge sand. Analysis of Cd content showed that at 7 stations in Ambon Bay detected Cd metal with the highest concentration at 4th station of Waiheru village was 0,6640 mg/Kg and the lowest concentration at 3th station of Kate-kate village was 0,0980 mg/Kg. Meanwhile, the highest Pb content was 20,075 mg/kg at 4th station and the lowest was 5,755 mg/kg at 2nd station of PLN Poka. The content of elements composition of sediment are SiO2, K2O, P2O5, Fe2, BaO, NiO and Ga2O3 but Cd and Pb metal was not detected.

Influence of the mechanical activation of raw mixes on the properties of foam glass from sand sludge

This paper reports the results of mechanical activation influence investigations on foam glass properties from sand sludge. Sand sludge is a waste product from crushing and screening plants for sand and gravel production. The results show the mechanical activation efficiency of the raw mix as a structural regulation tool and the properties of foam glass from sand sludge. Mechanical activation of the raw mix for 20min to a particle size of 50μm allows the sample to receive granular foam glass with a bulk density of 200kg/m3, a strength of 0.63MPa and a water absorption of 1.4%.

Lightweight aggregates produced from sand sludge and zeolitic rocks

This paper reports the results of investigations on manufacturing lightweight aggregates from sand sludge with zeolitic rocks added to decrease the foaming temperature. Sand sludge is a waste product from crushing and screening plants for sand and gravel production. Introduction of 20% zeolitic rock into the raw mix composition reduces the temperature required to produce lightweight aggregates by 50°C and improves their physical–mechanical characteristics. Lightweight aggregates using sand sludge with zeolitic rocks added have porous structures, with a total porosity of 60–70%; this material is recommended for use as lightweight aggregates for concrete and as heat-insulating filling.

Recycling of sand sludge as a resource for lightweight aggregates

This paper reports the results of investigations on manufacturing lightweight aggregate from sand sludge. Sand sludge is a waste product from crushing and screening plants for sand and gravel production. Preliminary studies demonstrate the feasibility of recycling sand sludge into lightweight aggregates. The properties of lightweight aggregates from sand sludge depend on both, the preliminary firing temperature of the frit and the foaming temperature of the green granules. Increasing the firing temperature of the frit from 800 to 900°C, the compressive strength, and the bulk and relative density of the granulated foam material decrease on the average by a factor of two, the water absorption decreases by 1%. The lightweight aggregates, derived from sand sludge at a temperature of 950°С, have a bulk density of 330kg/m3, a compressive strength of 0.18MPa and a water absorption of 0.1%.

The Removal of Indicator Microorganisms from Primary Treated Wastewater in Subsurface Reed Beds using Different Substrates

Subsurface, horizontal flow, experimental reed beds, were designed and built based on a combination of two design methodologies, that of the WRc and Severn Trent Water Plc and that of the USA, EPA. Four different growing media were used with a combination of top soil, gravel, river sand and mature sewage sludge compost, aiming to determine the best substrate for enteric pathogen removal. Eight units were constructed, two for each material. One bed for each pair was planted with Typha latifolia plants commonly known as cattails. Primary treated domestic wastewater, was continuously fed in to the bed for more than six months. All beds achieved a high reduction of Escherichia coli and faecal coliforms with the best results recorded in the gravel reed beds with an average removal above 3.3 log for E. coli and 3.0 for faecal coliforms. There was no significance difference in the performance of planted and unplanted reed beds.

The potential of some soil amendments to improve tree growth on metalliferous mine wastes

Trees are commonly planted on metalliferous mine wastes as a means of reclaiming these contaminated substrates. Other land-uses are often limited. However tree establishment is often poor owing to hostile substrate properties such as acidity, low macronutrient concentrations, high trace element concentrations, poor substrate structure and poor water retention. Soil amendments are a potentially cheap amelioration option. A factorial experiment was set-up to investigate the effects of seven amendments on the substrate chemistry and the growth and leaf chemistries of alder and sycamore. The amendments included ammonium nitrate, mineral phosphate and sulphate of potash fertilizers, calcareous sand, a superexpanding polyacrylamide gel polymer, cake sewage sludge and diatomite. The last two amendments are used here in a novel capacity. The most successful amendments with regard to their growth and leaf chemistry effects were found to be cake sludge and diatomite for alder and mineral phosphate, calcareous sand and cake sludge for sycamore. The least successful amendments were ammonium nitrate, sulphate of potash and calcareous sand for alder and ammonium nitrate for sycamore. The results differed according to the autoecological properties of the two species, with alder being easily the most productive. The implications of these results for tree-planting schemes are discussed.

Heavy Metal Removal from Soil by Coupled Electric‐Hydraulic Gradient

An investigation was carried out using coupled electric-hydraulic gradient to remove heavy metal contaminants from residual wastes. A mixture of spent foundry sand and millpond sludge containing high levels of Zn, Mn, and Pb was used as the contaminated source. An electric gradient was applied in a specially constructed decontamination cell, to generate a low pH solution by electrode reactions. Simultaneously, the low pH solution was pumped through the residual waste under a constant hydraulic gradient. Experiments were carried out under 0, 100, 150, and 200 V, with a constant hydraulic gradient producing an average flow of about 1 cc/min. At 0 V with hydraulic gradient alone, negligible amount of metals were removed. It was found that higher voltages removed higher percentages of metals of interest from the solid medium. At 200 V both Mn and Zn removal was about 72%. The removal of Pb was slower compared to Mn and Zn. At 100 V a negligible amount of Pb was removed; at 200 V only 46% Pb was removed from the solid mixture. It was demonstrated that a coupled electric-hydraulic gradient can be effectively utilized to remove heavy-metal contaminants from a porous medium.

Design factors for the scouring of deposited materials in water and wastewater treatment systems

Many water and wastewater systems require that sediments in the flow remain in suspension. Sometimes, auxiliary power sources, such as compressed air or pumping, are used to obtain scouring velocities in the system. The combined effects of pumping, compressed air, and gravity (floor slope) on the solid–liquid interaction and the velocity required to scour particles are presented herein.Two nondimensional parameters are developed to present data. Design curves for scouring sand, grit, and secondary sludge particles are presented and compared with data obtained for spherical particles. The particle terminal settling velocity is used to describe the significant particle characteristics. The use of prototypical particles and slopes, together with the dimensionless parameters, allows an application of results to prototype systems where auxiliary scouring sources may or may not be present.Using the information presented, it is possible to design water and wastewater systems in which particles must remain in suspension, with or without the use of auxiliary power sources. Key words: scouring velocity, settling velocity, compressed air, pumping, wet well floor slope, suspended particles.

TAILINGS POND BEHAVIOR AND CHARACTERIZATION OF OIL SAND TAILINGS SLUDGE

ABSTRACT Oil sand tailings are disposed of in large tailings ponds by upstream dyke construction and beaching. Sand separates and forms a gentle beach; the thin sludge flows into the pond as a density current, sedimentation takes place, and the rate of density increase rapidly becomes dominated by consolidation processes. The effect of the presence of bitumen on particles is an acceleration of sedimentation as the result of plastic collisions and agglomeration of particles. However, consolidation time is lengthened because the sludge solids have low relative densities and permeabilities. New system definitions are presented to account for the presence of bitumen as a non-mobile phase. A nomogram for oil sand sludge is presented to allow direct determination of sludge density and solids content from bitumen and water content. New experimental procedures for index tests are given, as the presence of bitumen creates laboratory difficulties. Grain size analysis and clay mineralogy require removal of bitumen, ...

USF, A New Crude Rubber

Abstract In preparing USF rubber by the preferred method, a field latex is preserved with formaldehyde as soon as possible after tapping. This chemical is effective in quickly and thoroughly stopping bacterial and enzymatic changes in the latex (Table I). Thus one of the most important sources of variability is eliminated at the start. The preserved latex is transported to the USF rubber plant and emptied into a tall settling tank; there it is allowed to stand for 48 hours for sand, dirt, and natural sludge components to separate. At the end of this time the supernatant liquid is withdrawn into a blending tank, and another charge is introduced into the settling tank. This process is repeated until the blending tank is filled. Then a fraction of the well-mixed latex from this tank, equal to a charge added from the settling tank, is removed for processing. The latex to be processed is highly diluted, acid is added, and the whole mass is stirred. Fine floes form on standing and rise to the surface, leaving a clear yellow serum. This is withdrawn, and the flocculates are washed by the further addition of water. The washed flocs are transferred through a pipe to the coagulating tanks normally used for preparing sheet rubber. The flocs have now become sufficiently destabilized, so coalescence to a slab of coagulum may occur by simple standing at air temperature. However, faster coalescence is obtained by brief mild treatment with steam. The coalesced slab is removed and passed through mills for the production of crepe or sheet. The wet rubber is hung up to dry in a conventional dryhouse. Finally the dried rubber is heavily compressed and shipped in rubber-wrapped bales. This process is described in the flow sheet of Figure 1.