Development of a model to be used as an indicator of oily wastewater pollution, fingerprinting and compliance using dimensional analysis
Year: 2020
Type: dissertation
Abstract: Water is the source of life because all living organisms cannot survive without it and it is the \nmost important liquid in the ecosystem hence protecting water resources and ensuring water \nquality should always be an issue of the highest priority at the top of all environmental issues. \nCurrently, both developing and developed countries are experiencing numerous water quality \nchallenges. Among the challenges include lack of adequate water due to pollution as well as the \nmanagement and disposal of oily wastewater effluents in water resources. Regarding the issue of \npollution due to oily wastewater, the current trend shows that, with the increase in \nindustrialization, the amount of oil used is also increasing, thus causing more stress in terms of \nmanagement and treatment of wastewater. Oily wastewater pollution has mainly been reported to \ncause hazardous effects to both organisms and the environment by causing the deterioration of \naquatic resources. This in-turn affect the quality of ground water, surface water, endanger human \nhealth, cause of atmospheric pollution, destroy/degrade natural landscape, and even cause safety \nissues due to the use of coalescence of the oil burner that arise. Due to this phenomena, various \nregulatory bodies have established some guidelines to regulate the disposal of oily wastewater \nthat is discharged to the environment. Therefore, oily wastewater needs to be treated prior to \nbeing discharged into the environment to comply with state and local disposal regulations. \nIndustries and companies that deal with activities that lead to the discharge of oily wastewater \nneed to comply to the enforced regulations to ensure that the characteristic of their effluents meet \nthe stipulated disposal criteria. The effluent quality requirements for discharge of oily \nwastewater to the municipal streams are determined by local and municipal authorities and, they \nmay vary from place to place. This dissertation focused on the development of a model that can \nbe used to indicate the quality of oily wastewater known as oil -produced water (OPW) which is \nnormally discharged by petroleum industries to into receiving water bodies. The model \ndevelopment was accomplished by using a measure of evaporation patterns in relation to certain \nenvironmental and climatic variables. This is possible because certain physico-chemical \nparameters that normally characterize OPW are known to have a direct relationship with the rate \nand pattern of OPW evaporation. However, due to the complexity of the relationship between the \nparameters being measured, it was imperative to employ dimensional analysis approach that is \nbased on Buckingham pi () theorem for the estimation of oil produced water evaporation \n(OPWE) as a function of clear water evaporation (CWE) and influencing parameters. The \nparameters that were investigated in this project includes climatic and environmental parameters. \nThe climatic parameters included wind speed (W), solar radiation (R) and air temperature (Ta). \nThe environmental parameters were: oil produced temperature (Topw), electric conductivity \n(EC), total dissolved solids (TDS), biochemical oxygen demand (BOD), total suspended solids \n(TSS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total petroleum \nhydrocarbons (TPH) and total organic carbon (TOC). The results have indicated that, the \nphysico-chemical analysis for the samples from the oil depot (petroleum industry) were found to \nbe within acceptable threshold limits except for COD, TPH and EC that slightly surpassed. These \nfindings and observations from this work suggests that, wastewater from this oil depot that was \nstudied should not be directly discharged into municipal channels, rivers, and streams unless it \nundergoes secondary and tertiary treatment processes. Alternatively, the wastewater may arrange \nfor an agreement with the municipals to allow for their effluents to be channelled to local \nmunicipality streams where they will undergo further treatment since most depot do not have \nappropriate facilities for post-treatment process. This is because, the chemical effluent must also \nadhere to the guidelines and regulations of the municipal where the wastewater will be \nchannelled into. Since most depots are not equipped with appropriate facilities to check for \ncompliance prior to the discharge of the effluents, this work has developed a multiplicative \nmodel for such purposes. Nonetheless, modelling the OPWE for compliance purposes has \nreceived little attention thus far. Driven by this knowledge gap, this project focused on the \ndevelopment of a model to predict the compliance of OPW effluents for both checking of quality \nand attaining the regulatory compliance. The modeling approach was based on experimental data \ncollected on the oil depot, South Africa for a period of six months. As a result of this analysis, a \nmultiplicative model to formulate OPWE as a function of influencing parameters indicated a \nreasonably well accuracy (RMSE = 0.49) for the OPWE estimation. The evaporation and \ncorrelation study supported the hypothesis. As shown by the evaporation patterns that most of \nthe time the effluent was compliant to the guidelines mostly during winter time than summer \ntime, and this observation was explained by the evaporation patterns that in summer when there \nis more solar radiation, the wastewater absorbed more heat and enhanced the evaporation rates \nwhich is directly related to both environmental and climatic parameters. Furthermore, the model \ndeveloped by this work, can be used for fingerprinting since OPWE from different processes may have similar chemical composition but in different levels and ratios. This can be exploited \nto differentiate them using the same developed model as the coefficients pattern tend to be \ncharacteristic to a certain OPWE and the model can then be used to fingerprint and identify \nculprits in case of discrepancies.
Author: Monatisa, Lerato Elizabeth
Language: English
Subfield: Waste Management and Disposal
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3115288039