The present article is an assessment of wastewater treatment processes in the oil refinery sector in Kazakhstan by comparing relevant experience of developed and developing countries. The legislation in this sphere, the treatment methods, the discharge process and the effect on the environment were evaluated following international and national regulations. In our study, the wastewater systems in three factories in Kazakhstan were assessed. Results show that, even though the environmental regulation in Kazakhstan promotes the polluter pays principle and follows the World Health Organization (WHO) recommendations, the oil refinery plants in Kazakhstan still contain exceeding concentrations of pollutants in their effluents. One issue is that the local legislation allows disposal of wastewater to natural or artificial ponds as long as the concentrations of pollutants in effluents are less than the already existing concentrations in the pond. Consequently, the factories can use ponds with an initially high concentration of contaminants. The high initial concentration of pollutants in the pond water is due to wastewater discharged before the implementation of current environmental regulations. This issue in the current legislation leads to the situation where there is no incentive for efficient wastewater treatment. The national law also lacks regulations regarding which methodology should be used to assess the pollutants in the wastewater. Thus, the control by national environmental office for each enterprise is negotiated separately between the factory and the governmental body. This gives the factory a strong position to define the parameters assessing the effluents. This has led to none of the factories measuring, e.g., heavy metals in discharged wastewater. Total petroleum hydrocarbons (TPH) concentration in wastewater is often exceeded at each factory and there is no analysis done for different hydrocarbon fraction. To overcome the issues described in the present study, we strongly recommended a unified and transparent methodology for the country’s oil refinery industry to assess important pollutants in discharged wastewater.
Petrochemical enterprises in Kazakhstan discharge polluted wastewater into special recipients. Contaminants infiltrate through the soil into the groundwater, which potentially affects public health and environment safety. This paper presents the evaluation of a 7-year monitoring program from one of the factories and includes nineteen variables from nine wells during 2013-2019. Several multivariate statistical techniques were used to analyse the data: Pearson's correlation matrix, principal component analysis and cluster analysis. The analysis made it possible to specify the contribution of each contaminant to the overall pollution and to identify the most polluted sites. The results also show that concentrations of pollutants in groundwater exceeded both the World Health Organization and Kazakhstani standards for drinking water. For example, average exceedance for total petroleum hydrocarbons was 4 times, for total dissolved solids-5 times, for chlorides-9 times, for sodium-6 times, and total hardness was more than 6 times. It is concluded that host geology and effluents from the petrochemical industrial cluster influence the groundwater quality. Heckman two-step regression analysis was applied to assess the bias of completed analysis for each pollutant, especially to determine a contribution of toxic pollutants into total contamination. The study confirms a high loading of anthropogenic contamination to groundwater from the petrochemical industry coupled with natural geochemical processes.
<p>Oil refinery industry historically has been related with groundwater pollution. According to WHO, contaminants may reach groundwater most easily as a result of discharge to the ground surface and subsequent infiltration through the soils, or releases from the ponds. Environmental Performance Review for Kazakhstan from UNECE states that oil refinery factories in Kazakhstan are one of the biggest sources of groundwater contamination despite of existing governmental and industry environmental monitoring systems. Recent studies showed that more than 50% of the people in rural Kazakhstan use groundwater for domestic purposes, consequently, many people potentially drink unsafe water. Despite this, oil refineries in Kazakhstan continue to discharge wastewater with high concentrations of different pollutants and these contaminants reach the groundwater very easily. The aim of this paper is to analyse and interpret a dataset obtained during a 6-year (2014&#8211;2019) monitoring program of the control of groundwater quality surrounding recipient of poorly treated wastewater discharges in one of the Kazakhstani industrial clusters. Multivariate statistical techniques and Heckman selection model were used for assessment of loading of natural and anthropogenic contribution to contamination, including separated evaluation of the impact of toxic substances.</p><p>The results show that PCAs have high loading of anthropogenic contamination to groundwater from the oil refinery industry coupled with natural geochemical processes. High concentrations of several parameters, such as total petroleum hydrocarbons, phenols, sodium, chlorides, sulphates, total dissolved solids and total hardness were identified. Water containing such exceeding concentrations of substances affects human body significantly and normally is considered to be rejected by consumers. By means of cluster analysis, the examined wells were combined in three groups according to the concentrations of chemicals and their locations. The results enable a prediction of the groundwater flow in the region studied as well as an estimation of which sites would be most severely affected by contamination. According to obtained data from Heckman analysis, focus of further research should be paid to the distribution of toxic contaminants. The industry is continuing to pollute the environment, which means that assessment of existent and future hazards is needed through improved monitoring system. Thus, the next step of the research considers contamination transport modelling for definite identification of groundwater flow and potentially affected rural areas.</p>
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