Slurry Ponds Research Articles

Environmental Monitoring of Pig Slurry Ponds Using Geochemical and Geoelectrical Techniques

The efficient management of slurry, which is a by-product rich in nutrients derived from feces, urine, cleaning water, and animal waste that stands out for its high concentration of nutrients such as nitrogen, phosphorus, and potassium, is of vital importance, highlighting the importance of slurry management in storage ponds, which. The Murcia–Spain region has an important number of pig farms. Hence, infrastructures dedicated to managing by-products are necessary to prevent environmental pollution and eutrophication of groundwater. The aim of a recent study was to evaluate the relationship between electrical values and geochemical parameters of pig slurry stored in a pond using ERT and geochemical analysis. In addition, the study was designed to monitor the pond to determine the geochemical characteristics of the slurry and to assess the risk of lateral contamination. The study results indicate a noticeable decrease in electrical resistivity values at 0.4 and 1.6 m depth in surveys 1 and 2. The reduction ranges from 50 to 100 percent. This paper presents a new method for monitoring slurry ponds using electrical resistivity tomography. This non-invasive method provides detailed information on the distribution and characteristics of the fluids, as well as a clear picture of the electrical resistivity of the subsurface.

Discard Coal as Filter Bed Material in Horizontal Subsurface Flow Constructed Wetlands: a Preliminary Study

Constructed wetlands (CWs) are engineered systems that use the natural functions of vegetation, substrate and microorganisms to treat wastewater. In coal mining regions, low calorific coals are dumped as discard. Left unattended, discard and slurry ponds contaminate surface and groundwater, cause erosion and sedimentation of particulates into nearby rivers and dams and contribute to atmospheric pollution and landslides. This study sought to investigate the use of South African bituminous discard as filter bed material for CW. A laboratory-scale horizontal subsurface flow (HSF) CW was supplied either nutrient-poor tap water (TW) or nutrient-rich advanced facultative pond (AFP) effluent, and quality of the treated water monitored over 6 months. Additionally, residual material from the discard coal filter bed was assayed after 6 months to establish substrate stability and to assess the contribution of phyto-biodegradation. Results showed successful establishment of P. australis on discard coal, better plant performance (measured as PSII quantum yield and biomass accumulation) and greater nutrient removal when fed AFP effluent. Discard coal filter bed material had greater ash content, sustained fixed carbon and C/N ratio with unchanged electrical conductivity (EC) and sulphate and phosphate concentration, indicative of balanced ion exchange. This, along with a > 70% reduction in NH4+-N concentration, yielded a final effluent within the general limit set by the South African authority for either irrigation or discharge, into a water resource that is not a listed water resource, for volumes up to 2000 m3 on any given day.

Slurry pond plants in gravel processing: Insights into improvements of the last 10 years or “From problematic cases to advanced solutions”

Slurry pond plants in gravel processing: Insights into improvements of the last 10 years or “From problematic cases to advanced solutions”

Coal and Coal Byproducts as Potential Sources of Rare Earth Elements (REE) in Indiana

The purpose of this study is to evaluate coal and coal byproducts (coal waste, coal ash, and acid mine drainage) in Indiana as potential sources of rare earth elements (REE). On a whole-rock basis, most Indiana coal samples have REE content below 100 ppm, and only some samples of the Brazil and Staunton Formations (Lower and Upper Block and Viking B coals) reach 100 ppm. Because REE concentrations vary between locations and within individual coal beds, and the correlations of coals within the Brazil and Staunton Formations are often uncertain, a better understanding of the stratigraphy of these formations is needed to identify the most promising REE horizons. Owing to a long history of coal mining, Indiana has numerous coal preparation plants and associated coarse-and fine-grained coal refuse (known, respectively, as gobs and slurry ponds). This paper reviews the available data on locations and volumes of these deposits. The total extent of slurry pond deposits was estimated at 2,765 acres, and the total volume estimates ranged from 94,000,000 to 136,000,000 cubic yards. No estimates are available for gob deposits in Indiana. To our knowledge, no REE data are available for coal preparation plant waste in Indiana, except for minimal data from coal slurry in Warrick County. Water streams from abandoned coal mines and coal processing (acid mine drainage, AMD) could also be a source of REE or other critical minerals; we review available data from AMD sites. Indiana, having many coal-fired power plants, has accumulated a large quantity of coal ash during its mining history. Our estimates indicate that coal ash deposits occupy ~2,184 acres, storing ~52,566,153 m3 of ash. Volume estimates for individual coal ash sites come from various sources and present our best estimates at this time. To our knowledge, no REE data are available on coal ash in Indiana. Such data would be of great value because coal ash deposits could be an important resource for REE, other critical minerals, or other high-value carbon products.

Coal-Based Nanoporous Carbon Electrode for High-Performance Supercapacitor: Surface and Diffusion Charge Kinetics in Aqueous and Non-Aqueous Electrolytes

South Africa generates around 60 million tonnes of coal discards each year, with over 1.2 billion tonnes landfilled in discard dumps and slurry ponds. The huge quantity of coal discards generated within the past decades, which is a significant liability to the mining industry and the environment, presents an opportunity to reuse this resource. This study investigated the potential of nanoporous carbon material from coal discard via KOH activation for use as electrode material in supercapacitors. Hierarchical morphology is seen via scanning electron microscopy (SEM). Raman spectroscopy reveals structural defects, X-ray Diffraction spectroscopy (XRD) confirms the material's amorphous nature, and N2 at 77k adsorption reveals a carbon material with high porosity and a surface area of 1424 m2/g.Electrochemical analysis reveals that the charge storage mechanism of the material is surface-controlled (non-faradaic) in the non-aqueous (TEABF4/ACN) electrolyte and diffusion-controlled (faradaic) mechanism in the aqueous (Na2SO4) electrolyte. The material has a higher specific capacitance (162 F/g) and cycling stability of 87.1% capacitance retention after 5000 cycles in Na2SO4. The material exhibits a better rate capability in TEABF4/ACN with 92.3% capacitance retention. A symmetrical two-electrode device using Swagelok T-cell assembly achieves energy densities of 15.5 and 10.4 Wh/kg in Na2SO4 and TEABF4/ACN, respectively, and a power density of 100 W/kg in both electrolytes. The variation in the capacitive performance of the material in both electrolytes is due to differences in electrolyte ion size, ionic conductivity, and pore structure. This study not only establishes a link between the structure of coal-based nanoporous carbon and its electrochemical performance in both electrolytes but also demonstrates the potential of coal-based functional materials for sustainable energy storage.

Delimiting Pig Slurry Affected Subsurface Areas by Combining Geophysical and Geochemical Techniques

In Spain, livestock farming is a significant activity area that generates substantial revenues and essential jobs. However, the actual impact that this intensive activity might have on the environment is not entirely understood. Moreover, coastal aquifers are subjected to a significant environmental pressure due to nearby growing population, intensive agriculture, and livestock farming. In this work, three representative pig slurry ponds, under semiarid conditions, were studied using different techniques to evaluate the subsurface conditions in terms of pH, electrical conductivity, salts, and nitrate content. The electrical resistivity tomography (ERT) technique was employed in this study, which provides electrical resistivity values from the subsurface materials and fluids. These electrical resistivity values were compared to data obtained from geochemical analyses to derive their relationships and establish the pig slurry-affected subsurface area. Thus, ERT-based lower electrical resistivity values were associated with higher salts concentrations and nitrate content. ERT values indicated a near-surface affected by slurry infiltration that coincided with the increase of geochemical values obtained from sample analyses. Additionally, Spearman’s correlation was used to evaluate the correlation between electrical resistivity data and the physical-chemical properties of soil. The most important pollutant accumulation mainly occurs in the two-meter depth. Therefore, the risk of slurry ponds affecting deep aquifers is limited in the studied area. Finally, this study proves a complete, affordable, and scalable methodology application to livestock residue storage facilities.

Full scale consolidation test on ultra-soft soil improved by prefabricated vertical drains in MAE MOH mine, Thailand

The reclamation of slurry pond with ultra-soft soil deposit using the prefabricated vertical drains (PVDs) with preloading technique in the Mae Moh mine, Lampang, Thailand is a challenging work and is illustrated in this paper. Geotextile reinforcement was used to strengthen bearing capacity of the soil foundation prior to the installation of sand platform. The delay of excess pore water pressure dissipation at the early loading stage occurred despite the occurrence of large settlements was a distinct behavior of the ultra-soft soil. Within the delayed time, the calculated average degree of consolidation based on measured settlements, Us increased while the calculated average degree of consolidation based on measured excess pore water pressures, Ue and the undrained shear strength, Su remained unchanged. Beyond the delayed time, both Ue and Su increased significantly with time and when Us > 90%, the difference between Ue and Us was observed to be small. It was suggested to use Us for approximation of Su when Us > 90% based on the SHANSEP's method. The successful installation and application of PVD to improve ultra-soft soil in this research is applicable for the ground improvement of similar problematic ultra-soft soils in international land reclamation projects.

Compressibility of ultra-soft soil in the Mae Moh Mine, Thailand

The compressibility characteristics of ultra-soft soils are an important issue for the deformation analysis of reclaimed land. This research study investigated the compressibility characteristics of ultra-soft soil present in a slurry pond, which is composed of the sedimentation and consolidation phases. The ultra-soft soil under the sedimentation process is termed as a slurry while the ultra-soft soil after completion of sedimentation is termed as a sedimentation soil. The samples were obtained from a slurry pond in the Mae Moh mine, Lampang province, Thailand. A series of sedimentation tests were performed on slurry at various initial water contents, wi, ranging from 116% to 437%. It was found that the sedimentation curve of the Mae Moh slurry was divided into two distinct different stages, being flocculation and settling. A novel parameter, being the critical water content (wcr) was proposed to separate the large sedimentation slurry and small sedimentation slurry. The wcr for Mae Moh slurry was found to be 171%. The sedimentation water content, ws was found to be equal to wcr for the slurry undergoing large sedimentation and lower for the slurry undergoing low sedimentation. The consolidation curve of the large sedimentation soil was assumed to be unique for different wi. The ws of small sedimentation soil is governed by wi and thus the consolidation curves are different for different ws. The consolidation curves of the ultra-soft soil at different ws can be assessed by a proposed generalized S-shaped equation. The intrinsic state line for high sedimentation soil was proposed for examining the stress state and predicting the consolidation curve of the ultra-soft soil, which is significant for reclamation projects.

Assessment of the Mode of Occurrence and Radiological Impact of Radionuclides in Nigerian Coal and Resultant Post-Combustion Coal Ash Using Scanning Electron Microscopy and Gamma-Ray Spectroscopy

Natural radionuclide concentrations in coal and coal ash can occur at levels sufficient to raise potential health and environmental concerns when (re)suspended or disposed into the environment. To evaluate such concerns, this study characterized coal and simulant coal ash samples obtained from two Nigerian coal mines (Okaba and Omelewu) using high resolution gamma spectroscopy combined with scanning electron microscopy and energy dispersive spectroscopy. Discrete uraninite particles were observed dispersed within the coal ash samples, alongside U and Th containing mineral grains (monazite and zircon) with monazite the most abundant radioactive mineral particles. The pitted and cracked surface morphologies of these radioactive particles (with sizes between 10 μm and 80 μm) indicate their susceptibility for disintegration into more harmful and readily inhalable PM2.5 aerosol particles, with the potential to deliver a localized dose and cause chronic respiratory diseases. The results of activity concentrations and radiological hazard indices for the coal ash samples from both mines were between three and five times higher than world average in soil, which imply that these coal ash materials should be suitably contained in slurry ponds to prevent hazards due to increased risk of prolonged indoor exposure to gamma radiation, radon gas, and inhalation of liberated radioactive particles.

The Impact of Coal-Powered Electrical Plants and Coal Ash Impoundments on the Health of Residential Communities.

BACKGROUND In North Carolina, coal-burning power plants remain the major source of electrical production. Coal burning generates coal ash that is stored in landfills and slurry ponds that are often located near residential communities, signifying high potential for environmental contamination and increasing health risks. We reviewed the literature on potential health effects of coal-burning plants to summarize current knowledge on health risks.METHODS We searched English-language publications issued between January 1, 1987, and December 31, 2017, on PubMed and Google Scholar.RESULTS The algorithm of identification, screening, eligibility, and inclusion/exclusion we used provided 113 peer-reviewed publications selected for the review. Over the past 30 years, scientists reported that the people living in close proximity to coal-fired plants had higher rates of all-cause and premature mortality, increased risk of respiratory disease and lung cancer, cardiovascular disease, poorer child health, and higher infant mortality. The elevated health risk was associated with exposure to air pollutants from the power plant emissions and to a spectrum of heavy metals and radioactive isotopes in coal ash.CONCLUSION In North Carolina, further studies are required to profile the severity of the cumulative impacts of multiple air, water, and soil contaminants related to coal-burning power plants and coal ash impoundments on human health and the environment. Prioritized study directions on evaluation of health impacts of coal-burning power plants in North Carolina are suggested.

Influence of Drainage with High Levels of Water-Soluble Salts on the Environment in the Verhnekamskoe Potash Deposit, Russia

Saline drainage from slurry storage facilities can deteriorate the properties of clay barriers in the beds of embankment dams and slurry ponds and cause saline drainage to infiltrate into groundwater. The chemistry of slurry material, drainage, springs, surface water, and soils was studied near the slurry storage facility of the Verhnekamskoe potash mine (Russia). Our study showed that the Na–Cl type mine drainage water, with high amounts of nitrogen compounds, increased the salinity of the groundwater and surface water, and the river valley ecosystems. As a result of ion exchange and leaching, the soil, groundwater, and surface water have elevated levels of \({\text{C}}{{\text{a}}^{2+}}\), \({\text{M}}{{\text{g}}^{2+}}\), \({\text{SO}}_{4}^{{2 - }},\) and \({\text{F}}{{\text{e}}_{{\text{total}}}}\), and extremely high \({\text{~N}}{{\text{a}}^+}\) and \({\text{C}}{{\text{l}}^ - }{\text{~}}\) values. Iron-rich precipitates and hydrogen sulfide tend to form down-gradient in the saline, water-logged seepage areas.

POSSIBILITIES OF WASTE MANGEMENT WHILE FORMING SOIL-LIKE ENVIRONMENT

The research results on the recovery of drilled solids and spent drilling mud with the use of phosphogypsum in combination with the humicagent «Rostok» showed that the resulting soillike environment can be used while recultivating slurry ponds and disturbed lands. Adding extra 5-20 % of spent drilling mud didn’t affect the chemical composition of the soil significantly. Using the humicagent «Rostok» favorably impacts the development of plants, besides the formation of a viable phytocenosis takes place with the significant increase of phytomass of vegetative aerial shoots by 28-31 %.

A computational study on gas–liquid flow in a lime slurry pond equipped with a rotary jet mixing system

The flue-gas desulfurization model was studied through computational fluid dynamics software. The oxidation air was asymmetrically pumped into the slurry pond. A rotary jet mixing system was established at the bottom center of the pond to agitate the lime slurry. The Navier–Stokes equation as the control equation, the standard k–ε turbulence model, sliding grids structure, and three-dimensional Eulerian multiphase flow of lime slurry were used for the numerical simulation. The independence of the meshes and the time step was verified. The distribution of the concentration of oxidation air and influents on the velocity of flow was analyzed with five angular velocities (0.01, 0.10, 0.20, 0.50, and 1 rad/s) for the rotary jet mixing. The simulation results showed that the angular velocity has a great influence on the velocity of the slurry and the distribution of the oxidation air.

Numerical investigation of multiphase flow in flue gas desulphurization system with rotary jet stirring

There exits multiphase flow of oxygenized air, lime slurry and limestone particles in power plant flue gas desulfurization (FGD) system. A rotary jet stirring device (RJSD) is installed in the slurry pond at the bottom center of absorption tank to get an appropriate mixing flow field so far as possible to get off sulfur dioxide. By employing the standard k-ε turbulence model and the Eulerian multiphase model, numerical investigations for liquid-solid and liquid-solid-gas flow field are presented to discuss the distribution of flow hydrodynamic parameters under a certain operational condition, respectively. In liquid-solid flow, limestone particle concentration shows a decreasing trend with the increase of the rotation angular velocity. The core jet length of the rotary mixer tend to be much longer with the increase of jet velocity under the surrounding pressure, but the dispersed slurry velocity tends to reduce after an initial increasing during the starting period due to the inadequate mixing process. This phenomenon shows that the stirring down-stream is more important than the advection stream in liquid-solid condition. Compared to the liquid-solid condition, the distribution of the air volume of fraction in gas-liquid-solid flow is getting uniform because of the participation of the solid phase, and the down-stream plays an important role in air lateral distribution. The concentration of the limestone particle in liquid-solid condition is higher than in the multiphase flow field. The reason is that the particle distributing velocity near the tank wall is lower and the vertical velocity is higher than in the liquid-solid condition when the jet down-stream velocity is equal. The numerical results could be a useful exploration for an attempt usage of rotary jet device in FGD system.

Separation of colemanite from tailings using the pilot scale flotation column

The tailing discharged in mineral processing plants is not only an economical loss, but also an environmental problem in mining industry. For example, fine grained tailing of Emet Boron Concentrator in Kutahya/Turkey is discharged to the slurry pond. However, the B2O3 content of the tailing is about 26%, and therefore, it can be accepted as a valuable boron source after the determination of suitable method/methods to recycle these tailings. In this context, this study was aimed to utilize a column flotation technique to recycle the colemanite tailings after scrubbing-classification process. The effect of some operational parameters such as bias factor and superficial gas velocity was investigated on column flotation of colemanite in terms of recovery and grade. According to the results, a concentrate having nearly 45% B2O3 with a recovery of 99% was obtained from the tailings sample with 26% B2O3 using the flotation column. Finally, a colemanite concentrate of 43.12% B2O3 was produced with a recovery of 93.46% using scrubbing-classification followed by flotation processes.

Mobility, Ecological risk and change in surface morphology during sequential chemical extraction of heavy metals in fly ash: A case study

Abstract Patratu coal based thermal power plant of Jharkhand, India uses Gondwana coal and generates ≈ 0.259 metric tonnes of fly ash. Only 3% of fly ash produced is utilized and rest is dumped as slurry, in the slurry pond and in the low-lying areas of the nearby villages. This study was aimed to find the mobility of metals in the fly ash samples by sequential extraction as well as to evaluate the ecological risk of the fly ash. The transformation of surface morphology after each step of sequential extraction was also studied by SEM-EDX. The results revealed that 13% of Cd and 1% of Ni was water soluble 48% of Ni, 23% of Mn, and 7% of Cd were in exchangeable fraction. The proportion in carbonate bound fraction was Cd (32%), Cu (15%), Zn (12%), Mn (6%), and Ni (3%) of the total metal content. Whereas, the proportion in Fe–Mn oxide bound fraction was Fe (46%), Mn (14%), Zn (13%) and Ni (3%); in organic bound fraction was Pb (38%), Cu (33%), Zn (16%), Cr (15%), Ni (13%), Mn (7%), Fe (6%), and Cd (2%) and in residual fraction was Cr (85%), Pb (62%), Mn (50%), Zn (59%), Cu (44%), Fe (47%), and Cd (25%). Pollution load index of metals in fly ash was more than one. Ecological risk index was also above 600. These values signify high ecological and pollution risk of the fly ash due to presence of heavy metals. So, implementation of proper remediation techniques is necessary to reduce the ecological risk of the fly ash.

Photocatalytic Treatment of Binary Mixture of Dyes using UV/TiO2 Process: Calibration, Modeling, Optimization and Mineralization Study

Abstract Photocatalytic treatment of a binary dye mixture (Acid Blue 113 (AB113) and Acid Red 114 (AR114)) has been done in a slurry pond reactor using TiO2 as a photocatalyst with UV light irradiation (UV-C). Two different methods, namely multivariate calibration and first order derivative spectrophotometric were used to quantify each dye separately in binary dye solutions. The behavior of the photocatalytic degradation of a binary dye mixture was predicted using an artificial neural network (ANN) model. Five process parameters (initial concentration of AB113 dye, initial concentration of AR114 dye, TiO2 dose, initial pH of the dye mixture and time were used as inputs and decolorization efficiency of AB113 and AR114 were used as output of the ANN. The parametric optimization has been done by the multi-response optimization with desirability function methodology. Optimization by Central Composite Design (CCD) effectively handles the relations among optimizing process variables and its prediction concurred well with the experimental run and artificial neural network (ANN) model. The reaction kinetic rates of decolorization of both dyes (AB113 and AR114) were found to be first order. Total organic carbon (TOC) removal and possible reaction pathway show the total mineralization of both dyes in binary dye mixture.

Environmental Assessment of Tetracycline’s Residues Detected in Pig Slurry and Poultry Manure

The widespread use of antimicrobials in animal husbandry has led to an increase in concentrations of antibiotics in animal faeces. Furthermore, the spreading of this waste as fertilizer on agricultural land indirectly introduces antimicrobial residues into the environment. This study examined samples of pig slurry and poultry manure for three tetracyclines—oxytetracycline (OTC), chlortetracycline (CTC) and doxycycline (DOC) and conducted an environmental evaluation of soils. The samples were taken from manure heaps on eight broiler chicken farms and from slurry ponds on eight pig farms. The tetracycline analysis was conducted using high-performance liquid chromatography combined with tandem mass spectrometry (HPLC/MS). The risk assessment was carried out on the basis of the estimated PECsoil value and the ecotoxicological information available for terrestrial organisms. TC concentrations were between >0.01 and 1.38 mg/kg. OCT was detected in 37% of the poultry manure and in 20% of the pig slurry samples. DOC was present in 50% of pig slurry samples with an average concentration of 1.2 mg/kg, while CTC was only found in one slurry sample at a concentration of 0.56 mg/kg. Compared with published values for these two farm animals from other countries, the TC concentrations obtained in this study were low. The environmental importance of the data generated was also discussed.

The Upgradation of Lignite Mining Waste Into Marketable Carbonaceous Fuel by the Selective Breakage Technique

The inter clay lignite waste from lignite mining in Giral block of Barmer district of Western Rajasthan has been transformed into marketable high calorific carbonaceous fuel, using a selective breakage technique. The coal can be cleaned near the mine mouth without using water; it will avoid transportation of rocks to a distance and also avoid the water pollution problem associated with the slurry ponds. The dry process will be economical as it will not utilize water and, thus, no dewatering or drying of the product will be required. Experiments were conducted with a coal sample containing 9.07% fixed carbon, 33.43% ash, 22.50% volatile matter, and marginally lower calorific value 1,869 Kcal/kg. The preliminary data indicate that by decreasing the size of coal fraction, the energy contents increasing gradually. The highest result was obtained for the size fraction (−) 2.36 to (+) 1 mm of lignite sample.

Vegetation dynamics on the posttechnogenic territories of Usinsk raion, Komi Republic, after various species of permanent grasses were sown

In order to reveal the optimal plant species for the protection of disturbed territories from erosion, two comparative experiments on the row sowing of permanent grass seeds collected in the northern regions of Russia (experiment 1) or originating from North America (experiment 2) have been arranged on the territory of the former slurry pond of the Vozeyskoe oil field (Usinsk raion, Komi Republic) dumped with a 1-m layer of sand. The sowing of grasses adapted to Northern Europe, together with the application of fertilizers on the technogenic substrate, yields the rapid formation of a closed grass cover, substrate-fixing turfing, and a mulch layer accumulating various nutrients and providing the further development of phytocenosis.