Zone Of Aeration Research Articles

Environmental impact assessment of acidic coal gangue leaching solution on groundwater: a coal gangue pile in Shanxi, China.

With the continual advancement of coal resource development, the comprehensive utilization of coal gangue as a by-product encounters certain constraints. A substantial amount of untreated coal gangue is openly stored, particularly acidic gangue exposed to rainfall. The leaching effect of acidic solutions, containing heavy metal ions and other pollutants, results in environmental challenges such as local soil or groundwater pollution, presenting a significant concern in the current ecological landscape of mining areas. Investigating the migration patterns of pollutants in the soil-groundwater system and elucidating the characteristics of polluted solute migration are imperative. To understand the migration dynamics of pollutants and unveil the features of solute migration, this study focuses on a coal gangue dump in a mining area in Shanxi. Utilizing indoor leaching experiments and soil column migration experiments, a two-dimensional soil-groundwater model is established using the finite element method of COMSOL. This model quantitatively delineates the migration patterns of key pollutant components leached from coal gangue into the groundwater. The findings reveal that sulfate ions can migrate and infiltrate groundwater within a mere 7years in the vadose zone of aeration. Moreover, the average concentration of iron ions in groundwater can reach approximately 58.3mg/L. Convection, hydrodynamic dispersion, and adsorption emerge as the primary factors influencing pollution transport. Understanding the leaching patterns and environmental impacts of major pollutants in acidic coal gangue is crucial for predicting soil-groundwater pollution and implementing effective protective measures.

Determination of engineering geophysical parameters of grounds on building sites and for seismic microzonation (methodical and metrological components of technology)

To ensure the reliability and long-term usage of high housing buildings, important industrial, infrastructural and other objects, it is necessary to carry out engineering geological investigations of grounds (near-surface rocks) as the basis of these structures. To prevent the potential danger of destruction of the objects, it is also necessary to perform microseismic investigations of the near-surface geological environment and to agree the obtained results with the engineering geological parameters in the section of the test boreholes. Engineering geological parameters, determined by geophysical methods, are named engineering geophysical parameters.
 To solve the geophysical engineering problems, including seismic microzonation, at the Institute of Geophysics of the National Academy of Sciences of Ukraine a modern investigation technology has been created. The technology is based on apparatus and methodical complex of radioactive logging, which involves gamma-ray logging (GL), density logging (DL) and neutron logging (NL). This paper presents the results of developing adequate methodical and metrological assurance of the radioactive logging complex as a key technology element.
 Complexation of methods GL, DL and NL (taking into account a priori data) and the use of the proposed approaches allow determining a wide set of engineering geophysical parameters: density, porosity, volume moisture, groundwater level, the content of shale, the content of clay minerals, water saturation, dry ground density, etc. The features of obtaining parameters by the radioactive logging complex in the zone of aeration and the zone of saturation are shown, as well as taking into account the influence of the shaliness on the determined parameters. The effectiveness of the technology has been demonstrated by specific examples and confirmed by independent laboratory measurements.

Modeling of convective-diffusion substance transfer and proposals as for development of an automatic system for monitoring and prevention of pollution of groundwater

At the enterprise being studied, due to losses, compounds of chromium accumulated on the soil floor of the workshop and gradually migrated in the zone of aeration of groundwater (aquifer). The level of groundwater in the area of the electric workshop is in the depth of around 10 m (as measured by the Pravoberezhna Expedition), that is, the ways of migration of chromium compounds in the area of aeration was about 10 m). The aquifer layer is located in flood-fed glacial deposits represented by sands of heter-ogenous grains. The sands are overlayed by loamy sand and loam with inclusion of gravel of basement crystalline rock. The filtration coefficient of sands varies from 1 m to 5 m per day, and of loams, from 0.1 m to 1 m per day. For this reason, the loam can only cautiously considered as low-permeable soil overlaying the aquafer. Therefore, it was more sound to consider a scheme of two-layer aquifer, in which the upper layer (loam) is about 1.5-m-thick, and the thickness of the lower layer (sand) is 5 to 15 m. Hexavalent chromium pollution using a model of convective-diffusive flow in an aquifer at a given research location was studied. The flow was defined as linear. The model is formu-lated as a differential equation and comprises the following variables: (C) – concentration of chromium compounds; (t) – time of observation; (Д) – coefficient of filtering (convective) dif-fusion; (Vn) – actual speed of filtration of the flow; (V) – existing speed of filtration of the flow; (na ) – active porosity of the soils forming the aquifer; (K) – filtering coefficient of the aquifer; (I) – hydraulic slope of the flow in the natural environment. Real input data and values of variables were used. Function С (х, t) was calculated and plotted, with its envelope curves determining the maximum concentration of the substance. Proposals are given as for development of an automated monitoring system and avoid-ance of the pollutant.

Assessment of groundwater lowering for urban infrastructure works, a case study in Sumbe, Angola/Africa

This paper describes the hydrogeological study developed for Sumbe city, in Angola, Africa, to evaluate the feasibility of employing existing wells to drawdown the water table in the central area of the city both to facilitate the urban infrastructure implementation and to increase its lifespan. The hydraulic conductivity of the unsaturated zone was estimated based on the open hole and double ring infiltrometer tests conducted in several points of the site to capture the variability of the hydrogeologic condition of the zone of aeration. The transmissivity and the hydraulic conductivity of the saturation zone were estimated based on an pumping test performed in a pumping well and two monitoring wells. Hand auger, SPT and rotary boring were carried out and combined with all field data information to produce a simplified conceptual model of the hydrogeologic system for the study site. Based on the survey data and by applying the Dupuit approximation of the Boussinesq equation for unconfined aquifers, the piezometric surface and the radius of influence of the well were computed for an operational steady condition. The study demonstrated that the entire site location is on a thick layer of clay and employing wells for groundwater lowering is unfeasible for either permanent or temporary purposes. For temporary groundwater lowering, collecting the water drained at the excavation by direct pumping was suggested. Finally, additional considerations regarding the sewerage/stormwater systems and the drainage system for the pavement base were also addressed. Keywords: groundwater lowering; infrastructure; hydraulic conductivity; influence radius of wells.

Soil-water-security Systems of Agriculture and Adaptation to Changes of Climate

In article the expediency of application of methods of protection soils from erosion and in general principles of the antierosion organization of territory of land tenure for adaptation of territories to changes of a climate is considered. The expediency of updating of these methods in connection with new results of supervision for runoff on slopes and the new purposes of their application is shown. In particular, it is shown, that antierosion constructions need to be placed above a place of concentration of a runoff, instead of on it as the probability of destruction of a construction in this place is great. Application the soil-water-security systems of agriculture provides regulation of a microclimate of territory (reduction of warming up of a surface), allows to lower peak of a high water from downpours, translating a part of a superficial runoff in intrasoil and underground and to these to prevent losses from them including loss of a fertile layer of soils, saturation by a moisture of a zone of aeration favorably influences development of forest vegetation and agricultural crops.

Analysis And Modelling Of Geoelectric Data Modeling For The Identication Of Groundwater aquifer At Cisarua Area, West Bandung

Groundwater is the main need of society in everyday life. Groundwater is one of renewable resources but it doesn’t mean that it can be exploitated without limit. Several factors that affect the availability of groundwater derived from nature such as geological conditions, rainfall, and green areas should be considered. Water in the soil is stored in a porous layer and has a good permeability is called an aquifer. Cisarua area is located in West Bandung regency, West Java which is a hilly area that has a topography with a slope ranging from normal to steep. The land use in this area is still dominated with plantation and forest as green area. Groundwater aquifer characteristics in that area needs to be examined and analysed for the needs of the community and agricultural business. In this research, the writer used inversion modeling technique of geoelectric data to visualize the condition of subsurface. Resistivity inversion modelling of apparent resistivity data as a result of resistivity method with Wenner-Schlumberger configuration is then carried out with least-square method. The initial model is modified in an iterative manner such that the sum of square error of the difference between the model response and the observed data values is minimized. The result of resistivity modelling is used for analysis of aquifer characteristic such as lithology, depth and structure along with considering geological reference. As the result of modelling, the area of measurement is divided into three zones which are Zone of aeration, Zone of Saturation, and endapan formasi. Zone of aeration is located at depth 0-25 m with resistivity 20-100 Ohm.m and the predicted lithology is gravel or weathered soil. Zone of Saturation (akuifer) is located at depth 25-60 m with resistivity 4-30 Ohm.m and the predicted lithology is sandstone or clay. Endapan Formasi Cibereum is located at more than 60 m from ground with resistivity more than 100 Ohm.m and the predicted lithology is sandy tuff or dry breccia.

Vertical Zonality of Nonferrous Metal Salt Settling-Down on Evaporation Barrier

The process of fluid mass transfer and formation of concentration zones on evaporation barrier in rock mass are studied. A series of experiments is carried out on a special testing plant in order to examine the process of settling-down on evaporation barrier and to determine parameters of vertical zonality in settling-down of simple and complex water-soluble nonferrous metal salts. The experimentation procedure is described. The regular patterns are found in the change in content in the direction toward the surface across the whole zone of aeration from the groundwater table. The higher salt concentration is observed on the rock mass surface, in the upper salt crust. This distribution law is typical either of simple or complex salts. The main parameters of settling kinetics and evaporation rate on the barrier are revealed and evaluated.

Расчет неустановившегося действия мелиоративного дренажа с углубленным учетом влияния зоны аэрации и инфильтрации

Расчет неустановившегося действия мелиоративного дренажа с углубленным учетом влияния зоны аэрации и инфильтрации

The impact of Sumy TPP on the environment of surrounding area

The purpose of the work is to determine the influence of thermal power plant on atmospheric air and soil and the study of heavy metals migration in environmental components.The estimation of the influence of Sumy TPP on the environment condition of the surrounding territories of Sumy during the income of pollutants with gas emissions and filtration from the zone of aeration and ash and slug dump is presented. For studies of the impact of the TPP on the adjacent territory was organized a network of observation points in the zone of influence the Sumy TPP. The assessment of atmospheric air pollution was carried out by studying the snow cover. Complex estimation of the pollution of adjacent territories to the thermal power plant was carried out using the total pollution indexSamples of snow cover, soil and vegetation were sampled, and tested for the content of heavy metals. An assessment was made of the pollution of snow cover and soils by the total pollution index and for the grass pollution by the coefficient of biogeochemical activity. Studies have shown that the level of snow cover pollution in the aeration zone of Sumy TPP is low. The level of soil contamination in the aeration zone of Sumy TPP is low, and the soils in the ash and slug dump zone: for the upper horizon are high, for the lower - medium, indicating the complex impact of atmospheric air pollution and the migration of substances from the body of the ash dip. The study of the most common types of grass Taracxacum officinale and Elytrigia repens showed the ways of migration of heavy metals and allowed to recommend these plants for bioindication of soil contamination by heavy metals. The assessment of the pollution of territories adjacent to the thermal power plant showed that the activity of Sumy TPP leads to increasing of heavy metals concentrations in environment.

О некоторых аспектах моделирования геодинамического риска на территориях рас-пространения просадочных грунтов.

In modeling geodynamic risk, the issues of developing special models of risk on the territories of distribution of loess and loess-like subsident soils under technogenic impact are of great relevance. Developing such models is a multi-stage process, which requires developing a model of the geological structure of a studied massif and setting predicted values of the properties of loess soils for preliminary quantitative evaluation of possible deformations in the natural conditions and in the zone of impact of constructions. Standard quantitative evaluation concerning the subsidence is carried out using results of testing the sample in limit states. Prognosis of the degradation of subsidence properties as a result of the break-up of the microaggregates in the zone of aeration is possible in conditions of impact of changes in the microaggregate compound on the subsidence. Using the method of defining the granulometric composition of the soil allows one to determine the area of soil condition in relation to dispersity. The method of GMDH allows one to develop a mathematical model of degradation of subsidence properties and calculate the predicted values of deformation in the zone of insufficient water content. The degradation of the subsidence properties of subaerial horizons is manifested most significantly at mild (30% of possible) increments of moisture and pressure of 0.1 mPa. In the area of additional pressure, predicted values of deformation insignificantly increase under moisture due to degradation, with increased moisture the break-up of the aggregates of sand fraction is followed by increase in the number of aggregates of smaller size (large-grained pulverescent ΔА3). The content of free thin fine-grained sandy (ΔM2), and clayey particles (ΔМ5, ΔМ6) increases, connected with aggregates of thin fine-sandy and large-grained clayey. The share of aggregates of large-grained pulverescent fraction also increases; the content of particles of this fraction assembled in the aggregates decreases. The dependency of deformation intensity in conditions of degradation of paleosol is of another character: the intensity of degradation increases as the pressure rises. The analysis of predicted values of aggregate content, free and assembled particles when there is change in moisture conditions showed that the process of the break-up of thin fine-sandy aggregates and increase in the share of large-grained clayey aggregates (composed of thin fine-sandy particles) is followed by occurrence of free particles of thin fine-sandy and thin clayey fractions.

Опыт создания прогнозных картографических моделей деградации просадочности на примере правобережной части г. Днипро.

Modeling of geodynamic risk is a highly relevant scientific issue; its solution requires solving particular problems in creating a model of the geological environment, selecting the risk factors, creating a model of process, acknowledging the scenarios and prognoses. Geodynamic risk in the areas of development of subsident soils can be defined as the possibility of massif deformations during changes in the soil condition (degradation). The limit state is the state of full water saturation, when the possibility of subsidence is low. Application of the three-term gradation to the scale of conditions sets the boundary values of soil moisture – the indicators of mild, average and critical changes. The predicted condition of the massif is set by a system of features – independent variables, input parameters correlated with values of moisture and values of degradation of subsidence properties. The predicted value of subsidence degradation under additional loading and in natural conditions is found using the group method of data handling. Widespread presence of subaerial loess-like formation in the composition of the geological environment in stratigraphic-genetic complexes of different composition and properties, and in water-bearing horizons, leads to intense development of exogenous geological processes and vulnerability of the environment.Typification of the geological structure of the massif was performed using the results of analysis of numerous engineering-geological studies (Dnipro, 1960-2007). The total number of wells is 785, the depth varies from 15 to 56 m. The mapping of surfaces of particular horizons, terrain, thickness of aeration zone was developed using a Surfer demo-version. Interpolation was made using the Kriege method. Development of models of surfaces of the top of and thickness of horizons and took the erosional washout into consideration. The analysis of cartographic material shows that loess and paleosol horizons have different consistencies. The following processes were modeled: the change in the condition in relation to moisture of the subsident soil massif within the zone of low-intensive aeration, the value of additional pressure equals 0.3 MPa; the change in the condition in relation to moisture of the subsident soil massif within the zone of averagely intensive aeration, the value of additional pressure equals 0.3 MPa (Fig. 5 b). The results of the prognosis indicate the importance of predicting the subsidence degradation as a factor of geodynamic risk, maximum values reach 0.24 m. Comparing this value to the value of acceptable settling of constructions may suggest the practicability of introducing the method of predicting subsidence to the practice of engineering-geological studies and planning.

Зміни параметрів мікроструктури лесових ґрунтів під час фільтрації

Increasing the level of groundwater of permanent and temporary transfer of static and dynamic loads, changing the thermal regime lead to changes in the state of the soil mass, soil properties as a complete water saturation zone and in the zone of aeration. The high vulnerability of structural and textural characteristics of soils in the man-made impact contributes to their the rapid degradation. Degradation of properties and structure of soil is the basis suffusion, subsidence and gravity of natural and industrial disasters and requires further tostudy (Mokritskaya, 2013). The purpose of research is to determine changes in the parameters of the microstructure of loess soils as a result of filtering. The object is aeolian and deluvian loams and sandy selected in the gully Yevpatorian (Dnipro). The subject is the effect of filtering water to change the microstructure of the soil. The results showed that the biggest removal particles of 0.25 — 0.05 mm observed in e PII zv soils, mostly fine particles are made of finely sand fraction, which is kind of addition to the large silty fractions. Revealed that the microstructure parameters aeolian-diluvial deposits filtering virtually no effect, unlike eluvial deposits, which due to larger content of ions Ca2+ (for e PII zv it is 0.6 mmol/100 g soils) capable of greater particle transfer. Perhaps because the aggregate method of preparation reflects changes in the quantity of unstable water aggregates but it they are not took place, filtering water through rock leads to more complex transformations mikrostukture than just the removal of particles in the lower horizons bedding. The restructuring is to ionic levels and that it reflect the standard and dispersed methods of preparation. Therefore, to identify changes in microstructural parameters for filtering technique should be used "microstructure" (Ryaschenko, 2010). As a result of filtering during the period microstructure change did not take place, the observation was carried out to stabilize the rendered particles allows us to consider these results conditionally correct.

Research on the adsorption and migration of sulfa antibiotics in underground environment

This study investigated the adsorption and migration characteristics of four sulfa antibiotics, which had been detected in the soil and groundwater in the northeast of China, namely sulfathiazole (ST), sulfamethyldiazine (SM), sulfamethazine (SM2), sulfamethoxazole (SMX); the groundwater pollution index was calculated by EPI Suite. Experimental results showed that the sulfa antibiotics have strong ability of migration, which was in the order of SMX > SM > SM2 > ST, and the content of sulfa antibiotics which passed through the zone of aeration and then entered the aquifer is above 78 %. Fe3+, Mn2+, iron oxide, manganese oxide and humic acid had a positive effect on the adsorption of sulfa antibiotics. The purpose of this study was to provide a scientific basis for removing the antibiotics in the soil and water.

Опыт прогноза деформаций просадки массива методами индуктивного моделирования

The article describes the experience of subsidence prediction of deformations of the array using the methods of inductive modeling. Inductive modeling methods, in particular methods of group account of arguments and neural networks can solve the problem of the forecast for the incomplete and irregular data on the state of a complex system. To solve the problem in the article involved the program trial – versions of Surfer, STATISTICA and authoring program Koryashkinoy L.S. In the course of solving the problem was carried out construction of spatial models of environment and its components (relief surfaces and capacities of individual horizons in the volume of the aeration zone, the surface level of underground water); models of behavior; predictive models subsidence. Construction of spatial models is performed in a scale of 1:25 000, in the conventional coordinate system, in an environment «Surfer». The data on the properties of the horizons of the zone of aeration were studied by statistical, correlation and regression types of stochastic analysis. The results of the primary analysis showed that the samples are heterogeneous and unbalanced by the values of skewness and kurtosis. Regression analysis showed that the use of stepwise regression method does not provide a significant multiple regression model. To forecast the relative subsidence were built inductive model of the relative depth of the subsidence and indicators of physical condition. According to the forecast values of subsidence relative to the regular grid of reference points in the depth interval specified capacity of the aeration zone, calculated the value of the total drawdown in a natural, middle and status of the array. The spatial position of the zones of change of the total drawdown indicates the position of the zones with different values forecast and realized risk. As a conclusion of the article can be said that the application of inductive modeling allows you to forecast changes in the natural subsidence with increasing humidity as a result of changes in the status of ground array.Key words: model, regression, drawdown, forecast

Method to make nests of useful components by way of accumulation

Experimental evaluation is given for mineral preconcentration in a bed of a sorption collector in percolation of low concentration useful components from aqueous solutions of salts. Sorption collectors represented by interlayers of lignite, peat, marble and vermiculite are included in an evaporation barrier installed in subsurface zone of rock mass aeration. Accumulation properties of such geochemical sorption barriers are examined. Migrating solution was aqueous solutions of salts of cobaltous and nickelous nitrates. It has been found feasible to shape beneficiation zones under up-going capillary permeation of the solutions through the sorption barriers in the zone of aeration in rock mass.

GEOCHRONOMETRY OF CENOZOIC OROGENY IN THE ALTAI-SAYAN REGION BY PYROMETAMORPHIC COMPLEXES: A GEOLOGIC FOUNDATION

Melted pyrogenic rocks - paralavas - are analogous to magmas regarding their certain mineralogical and geochemical characteristics. Present methods of volcanic rocks radiometric dating may be used for the absolute dating of coal fires. Petrologic study of pyrometamorphic complexes was fulfilled in the Prokop'evsky-Kiselevsky region of Kuzbass; some rock groups were shown to be applicable for such dating. First radiometric datings were obtained: older group - 1.22 ± 0.44 Ma (40Ar/39Ar) and 1.8 ± 0.2 (K/40Ar) - is represented by rocks from the block between the Tyrgansky thrust and Afonin-Kiselevsky overlap fault. Another, younger group - 0.19 ± 0.26 Ma (40Ar/39Ar) and 0.48 ± 0.11 Ma (K/40Ar) - consists of paralavas from the more eastern block between Afonin-Kiselevsky and Kiselevsky overlap faults. These datings correspond to main stages of neotectonic activization of the boundary between the Salair and Kuznetsk basin because the coal fires were contemporised to the uplifts of the territory and to the putting the coal into the zone of aeration.

ON MULTIVARIATE APPROACH TO EVALUATE THE PROTECTION OF AQUIFERS AT DEVELOPMENT OF WESTERN SIBERIA OIL-AND-GAS BEARING AREAS

The qualitative and quantitative assessment of ground waters protectability based on the regional specific charac-teristics of the lithology and thickness of impermeable deposits of the zone of aeration and overlying deposits, a ratio of confined and ground water levels, the soils and clay rocks absorptivity. The article gives the author's vision of ground waters natural protectability. It presents a quantitative estimation by three most well-known methods. Based on the calculations made a map of protectability of fresh ground waters in the Atlym-Novomikhailovsk complex for Nizhnevartovsk district was constructed.

Fayalite-sekaninaite paralava from the Ravat coal fire ( central Tajikistan)

We studied ferrous paralava, a high-temperature rock, produced by complete fusion of the sedimentary protolith in the Ravat natural coal fire which has been on for over two thousand years. The paralava was sampled from the Fan-Yagnob coal deposit at the Kukhi-Malik site in the vicinity of former Ravat Village in central Tajikistan. This rock contains fayalite, sekaninaite, hercynite, Ti-magnetite, tridymite, and siliceous glass. Low-Ca pyroxene (clinoferrosilite), globules of sulfides (mainly pyrrhotite) and Fe-Ti oxides, secondary greenalite (after fayalite) and hematite are minor. Paralava includes xenoliths of partially molten clinkers (up to 20 vol.%) composed of mullite, cordierite, tridymite, and relict detrital quartz. We found relatively high Fe contents (100⋅Fe/(Fe+Mg) > 60) in mafic minerals, high K 2O enrichment (up to 1.4 wt.%) in sekaninaite, and an unusually low CaO content (0.5 wt.%) in the rock. The Ravat paralava appears to be derived from a mixture of pelitic rocks (50–70%) and iron-rich rocks (30–50%), but without participation of calcareous material, which explains the low CaO and the absence of plagioclase and Ca-bearing pyroxene. The primary melt was as hot as >1210 °C, and the coal-fired fayalite-sekaninaite paralava crystallized at 1200–1100 °C, at a relatively low oxygen fugacity (near the QFM buffer), outside the zone of active aeration. Large-scale crystallization of ferrospinels and fayalite led to increasing Al 2O 3 and SiO 2 in the melt whence sekaninaite and tridymite crystallized as later phases. The residual melt progressively acquired a more silicic-aluminous composition, rich in K 2O, CaO, and P 2O 5, and became quenched to glass at >1080–1090 °C, when temperature dropped abruptly, possibly, by roof collapse or opening of large cracks, as it usually happens in underground coal fires.

Simulation of the process of moisture transfer in the zone of aeration on the basis of the capillary potential equation

A time-dependent model of the regime of moistening in the rootage layer of ameliorated soil is presented. It is based on the solution of a differential equation for the capillary potential of moisture transfer in the zone of soil aeration. The motion of moisture from the surface of groundwater into the layer of active moisture transfer of the aeration zone determines the aqueous-physical properties of soil, the moisture saturation degree of this layer, and the position of the groundwater level. The motion of soil moisture is characterized by an unsteady regime in which the moisture content changes not only with depth, but also in time.

Groundwater pollution due to sugar-mill effluent, at Sonai, Maharashtra, India

Analyses of 126 samples collected from 18 dug wells in the shallow basaltic aquifer over a period of 7 months have revealed spatial as well as temporal changes in the chemical properties of groundwater. While the temporal changes have been attributed to dilution and concentration phenomena governed by climatic factors, the spatial variations in the geochemical characteristics of groundwater appeared to be related to pollution due to effluents from the Mula Sugar Factory. The cause of groundwater pollution is the effluent carried by a stream flowing through the area. Fluctuations in the groundwater table, influent water quality character of the stream, less capacity to accommodate large volume of effluent and occurrence of zero base flow (under natural conditions) in the stream are the factors favoring infiltration of constituents of waste water into the underlying weathered basaltic aquifer. Pollutants have entered into the shallow aquifer by downward percolation through the zone of aeration to form a recharge mound at the water table and, further, lateral movement below the water table. The plume of polluted groundwater has a lateral extent of a few meters in the upstream area and more than 400 m on either side of the stream in the downstream part. The zone of polluted groundwater has an areal extent of more than 3.5 km2. Groundwater is the only source available for drinking and agricultural purposes. It is recommended that the base of the lagoons and the stream used for release of plant effluent should be waterproofed for the protection of groundwater in the Sonai area.