Recent Developments in Emerging Contaminants Determination and Treatment Technologies

A significant hazard to human life has been created by the intensive and widespread nature of enterprises that release large amounts of ECs into the environment. The chance of unknown ECs leak, fate, transit, and exposure by numerous companies are making the job of policymakers more challenging. The incidence, transformation, degradation pathways, and potential treatment of ECs need to be better understood, even though their pathway is still not entirely known. Unfortunately, because of their low concentrations and great solubility, EC poisons can harm both people and wildlife, as well as local ecosystems, and they are challenging to remove. Additionally, due to an absence of stringent legislation and insufficient toxicological data on these ECs, this release remains unregulated. In addition, it is yet unknown how much of an environmental and health impact these emerging pollutants entail. Advances in analytical chemistry, technology, and engineering have made it possible to identify specific ECs in the environment. To detect and count environmental ECs, more research in this field is required

The Impact of Climate Change and Soil Classification on Benzene Concentration in Groundwater Due to Surface Spills of Hydraulic Fracturing Fluids

Hydraulic fracturing drilling technology can cause a high risk of surface spill accidents and thus water contamination. Climate change together with the high water demand and rapid increase in industrial and agricultural activities are valued reasons why we should all care about the availability of water resources and protect them from contamination. Hence, the purpose of this study is to estimate the risk associated with a site contaminated with benzene from oil spillage and its potential impact on groundwater. This study focused on investigating the impact of soil variability and water table depth on groundwater contamination. Temperature-dependent parameters, such as soil water content and the diffusion of pollutants, were considered as key input factors for the HYDRUS 1D numerical model to simulate benzene migration through three types of soil (loamy, sandy clay loam, and silt loam) and evaluate its concentration in the water aquifer. The results indicated that an anticipated increase in earth’s average surface temperature by 4◦C due to climate change could lead to a rise in the level of groundwater pollution in the study area by 0.017 mg/L in loamy soil, 0.00046 mg/L in sandy clay loam soil, and 0.00023 mg/L in silt loam soil. It was found that climate change can reduce the amount of benzene absorbed from 10 to 0.07% in loamy soil, 14 to 0.07% in sandy clay loam soil, and 60 to 53% in silt loam soil. The results showed that the soil properties and solute characteristics that depend on the temperature have a major and important role in determining the level of groundwater pollutants

Recent advancements in the treatment of palm oil mill effluent (POME) using anaerobic biofilm reactors: Challenges and future perspectives

Palm oil is the most utilized vegetable globally which is mostly produced in countries such as Malaysia, Indonesia and Thailand. The great amount of POME generation from palm oil mills is now a threat to the environment and require a suitable treatment of POME to reduce the organic strength in accordance with the standard discharge limit before releasing to the environment. Currently, the technology to combine the anaerobic process and biofilm system in bioreactors have produced a fresh idea in treatments of high strength wastewater like POME. Anaerobic biofilm reactor is a convincing method for POME treatment due to its significant advantages over the conventional biological treatments consisting of anaerobic, aerobic and facultative pond systems. Overall, integrated anaerobic-aerobic bioreactor (IAAB) can remove more than 99% of chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) with the combination of anaerobic and aerobic digestion for POME treatment. It has better performance as compared to up-flow anaerobic sludge blanket (UASB) and up-flow anaerobic filter (UAF) with 80% and 88–94% COD removal efficiency respectively. Anaerobic pond was found to perform well also by removing 97.8% of COD in POME but require long retention time and larger land. Hence, this study aims to provide intensive review of the performance of the anaerobic biofilm reactor in treating POME and the recent advancements in this technology. The limitations and future perspectives in utilization of anaerobic biofilm reactor during its operation in treating POME are discussed

Anaerobic treatment of ultrasound pretreated palm oil mill effluent (POME): microbial diversity and enhancement of biogas production

In this study, palm oil mill effluent (POME) treated by ultrasonication at optimum conditions (sonication power: 0.88 W/mL, sonication duration: 16.2 min and total solids: 6% w/v) obtained from a previous study was anaerobically digested at different hydraulic retention times (HRTs). The reactor biomass was subjected to metagenomic study to investigate the impact on the anaerobic community dynamics. Experiments were conducted in two 5 L continuously stirred fill-and-draw reactors R1 and R2 operated at 30 ± 2 °C. Reactor R1 serving as control reactor was fed with unsonicated POME with HRT of 15 and 20 days (R1-15 and R1-20), whereas reactor R2 was fed with sonicated POME with the same HRTs (R2-15 and R2-20). The most distinct archaea community shift was observed among Methanosaeta (R1-15: 26.6%, R2-15: 34.4%) and Methanobacterium (R1-15: 7.4%, R2-15: 3.2%). The genus Methanosaeta was identified from all reactors with the highest abundance from the reactors R2. Mean daily biogas production was 6.79 L from R2-15 and 4.5 L from R1-15, with relative methane gas abundance of 85% and 73%, respectively. Knowledge of anaerobic community dynamics allows process optimization for maximum biogas production

An overview of per-and polyfluoroalkyl substances (Pfas) in the environment: Source, fate, risk and regulations

The current article reviews the state of art of the perfluoroalkyl and polyfluoroalkyl substances (PFASs) compounds and provides an overview of PFASs occurrence in the environment, wildlife, and humans. This study reviews the issues concerning PFASs exposure and potential risks generated with a focus on PFAS occurrence and transformation in various media, discusses their physicochemical characterization and treatment technologies, before discussing the potential human exposure routes. The various toxicological impacts to human health are also discussed. The article pays particular attention to the complexity and challenging issue of regulating PFAS compounds due to the arising uncertainty and lack of epidemiological evidence encountered. The variation in PFAS regulatory values across the globe can be easily addressed due to the influence of multiple scientific, technical, and social factors. The varied toxicology and the insufficient definition of PFAS exposure rate are among the main factors contributing to this discrepancy. The lack of proven standard approaches for examining PFAS in surface water, groundwater, wastewater, or solids adds more technical complexity. Although it is agreed that PFASs pose potential health risks in various media, the link between the extent of PFAS exposure and the significance of PFAS risk remain among the evolving research areas. There is a growing need to address the correlation between the frequency and the likelihood of human exposure to PFAS and the possible health risks encountered. Although USEPA (United States Environmental Protection Agency) recommends the 70 ng/L lifetime health advisory in drinking water for both perfluorooctane sulfonate (PFO) perfluorooctanoic acid (PFOA), which is similar to the Australian regulations, the German Ministry of Health proposed a health-based guidance of maximum of 300 ng/L for the combination of PFOA and PFOS. Moreover, there are significant discrepancies among the US states where the water guideline levels for the different states ranged from 13 to 1000 ng L−1 for PFOA and/or PFOS. The current review highlighted the significance of the future research required to fill in the knowledge gap in PFAS toxicology and to better understand this through real field data and long-term monitoring programs

Appraisal of groundwater contamination from surface spills of fluids associated with hydraulic fracturing operations

Contaminated groundwater is a priority issue on the environmental agendas of developed countries. Therefore, there is an obvious need to develop instruments and decision-making mechanisms that allow the estimation of the risk to human health due to the presence of contaminants in soils and groundwater, in a fast and reliable manner. Thus, this study aims to assess whether the spilling of hydraulic fracturing fluids prior to injection has a potential risk to groundwater quality in the Kern County Sub-basin, California, by identifying the hydrological factors and solute transport characteristics that control these risks while taking into consideration the temperature rises due to climate change. The approach uses the concept of the groundwater pollution risk based on comparing the concentration of pollutants within the water table by using a predetermined permissible level. The current average annual temperature and that by the end of the 21st century was used to estimate the diffusion of benzene through three types of soil by using HYDRUS-1D software. The software was used to predict the contaminant concentration profile of benzene in the water table with special reference to the impact of surface temperatures. The results showed that an expected rise of the surface temperature by 4.3 °C led to an increase in the concentration of benzene by 2.3 μg/l in sandy loam soil, 6.8 μg/l in silt loam soil, and finally, 2.6 μg/l in loam soil. The results show that climate change can substantially affect soil properties and their chemical constituents, which then play a major role in absorbing pollutants

Evaluation of oil palm fiber biochar and activated biochar for sulphur dioxide adsorption

The emission of sulphur dioxide (SO2) gas from power plants and factories to the atmosphere has been an environmental challenge globally. Thus, there is a great interest to control the SO2 gas emission economically and effectively. This study aims to use and convert abundantly available oil palm fiber (OPF) biomass into an adsorbent to adsorb SO2 gas. The preparation of OPF biochar and activated biochar was optimised using the Response Surface Methodology (RSM) based on selected parameters (i.e., pyrolysis temperature, heating rate, holding time, activation temperature, activation time and CO2 flowrate). The best adsorbent was found to be the OPF activated biochar (OPFAB) compared to OPF biochar. OPFAB prepared at 753 °C for 73 min of activation time with 497 ml/min of CO2 flow yields the best adsorption capacity (33.09 mg/g) of SO2. Meanwhile, OPF pyrolysed at 450 °C of heating temperature, 12 °C/min of heating rate and 98 min of holding time yield adsorption capacity at 18.62 mg/g. Various characterisations were performed to investigate the properties and mechanism of the SO2 adsorption process. Thermal regeneration shows the possibilities for the spent adsorbent to be recycled. The findings imply OPFAB as a promising adsorbent for SO2 adsorption

Ancillary palm oil fuel ash (POFA) in sequencing batch reactor for enhancing recalcitrant pollutants removal from domestic wastewater

Domestic wastewater has been generated massively along with rapid growth of population and economic. Biological treatment using sequencing batch reactor (SBR) augmented with palm oil fuel ash (POFA) was investigated for the first time. The performance of POFA in enhancing biological treatment of wastewater has not been tested. The porosity property of POFA can improve SBR efficiency by promoting growth of mixed liquor suspended solids (MLSS) and formation of larger flocs for settling and facilitating attachment of microorganisms and pollutants onto POFA surfaces. The properties of POFA were tested to identify morphological properties, particle size, surface area, chemical compositions. Four SBRs, namely SBR1, SBR2, SBR3 and SBR4 were provided with aeration rate of 1, 2, 3 and 4 L/min, respectively. Each reactor was augmented with different dosages of POFA. Optimum aeration rate and POFA concentration were identified by the performance of SBRs in removing chemical oxygen demand (COD), ammoniacal nitrogen (NH3–N) and colour from domestic wastewater. The results showed the most efficient COD (97.8%), NH3–N (99.4%) and colour (98.8%) removals were achieved at optimum POFA concentration of 4 g/L in SBR and aeration rate of 1 L/min. The study also found that higher aeration rate would contribute to the smaller specific size of flocs and decrease the pollutant removal efficiency

Influence of alum sludge ash and ground granulated blast furnace slag on properties of cement mortar

This study aims to investigate the effects of partially carbonized alum sludge ash (ASA) which had been treated at the temperature of 200–300 °C and Ground Granulated Blast Furnace Slag (GGBFS) as supplementary cementitious materials on fresh and hardened properties of cement mortar. In this study, 10 mixtures with maximum replacement levels of ordinary Portland cement (OPC) with ASA and GGBFS up to 6.0 wt% respectively. The setting time and flow table tests were performed on fresh concrete, while the hardened properties (density, compressive strength, flexural strength, water absorption coefficient, porosity and water absorption) were investigated on two concrete curing ages (i.e., after 7 days and 28 days). The results showed that, the mechanical strengths, workability, and density of mortar tended to decrease as the replacement level of OPC with the ASA increase, while the setting time increase with the increase of ASA content. In addition, the ASA and GGBFS enhanced the water absorption coefficient and water absorption properties of concrete at all ages. The highest compressive strength a mortar can be produced from this study after being cured for 28 days is 20.6 MPa 2.0 wt% of ASA and 4.0 wt% of GGBFS were used to partially replace OPC to produce the mortar which had workability of 156 mm. Overall, incorporation of ASA as a partial replacement of cement in mortar production can partly reduce the volume of alum sludge in landfill

Sustainable energy, economic, and environmental impacts of small-scale wind turbines: A comprehensive study

Gaza has been suffering from a major crisis in the energy sector, and there is a need to adopt sustainable sources of renewable energy such as wind energy to meet the growing energy needs. This study focuses on wind energy harvesting potential as a renewable, clean source of energy in the Gaza Strip for a sustainable economy and environmental conservation. Three-blade horizontal turbines were tested with rotor diameters of 4.4, 3.8, and 3.2 m. The effect of the wind speed and the rotor diameter on the tip speed ratio (TSR), the power factor (Cp), and the turbine produced power were investigated. The result showed that annual energy of 4851.87, 3618.85, and 2566.28 kWh achieved at rotor diameters of 4.4, 3.8, and 3.2 m, respectively. The result also exposed that the total saving per year is equal to $824.8,$615.2, and $436.3 at rotor diameters of 4.4, 3.8, and 3.2 m, respectively. The payback periods of a turbine with 4.4 m rotor diameter were 8.3 years. Also, using a turbine with a rotor diameter of 4.4 m can reduce 4124 kg/yr of CO2 emissions. It is recommended to encourage the private sector to invest in wind energy in Gaza to ensure economic growth and environmental sustainability