A new treatment step of bioelectrochemically treated leachate using natural clay adsorption towards sustainable leachate treatment.

Standalone and combined leachate treatment mechanisms suffer from low treatment efficiencies due to leachate's complex, toxic, and recalcitrant nature. Bioelectrochemical system (BES) was used for the first time to investigate the treatment of leachate mixed wastewater (WW) (i.e., diluted leachate, DL) (DL ≈ L:WW = 1:4) to minimize these complexities. A natural clay (palygorskite) was used as adsorbent material for further treatment on the BES effluent (EBES) while using two different masses and sizes (i.e., 3 g and 6 g of raw crushed clay (RCC) and 75 µ of sieved clay (75 µSC)). According to bioelectrochemical performance, BES, when operated with low external resistance (Rext = 1 Ω) (BES 1), showed a high removal of COD and NH3-N with 28% and 36%, respectively. On the other hand, a high Rext (100 Ω, BES 100) resulted in low removal of NH3-N with 10% but revealed high COD removal by 78.26%. Moreover, the 6 g doses of 75 µSC and RCC showed the maximum COD removals of 62% and 38% and showed the maximum removal of NH3-N with an average range of 40% for both sizes. After efficient desorption, both clay sizes resulted in regeneration performance which was observed with high COD (75%) and NH3-N (34%) on EBES. Therefore, when BES and clay adsorption technique sequentially treated and achieved with combined removal of ~ 98% for COD and ~ 80% of NH3-N, it demonstrated an efficient treatment method for DL treatment.

Characterization and exposure assessment to urban air toxics across Middle Eastern and North African countries: a review.

Middle East and North African (MENA) countries over the decades are experiencing rapid industrial and infrastructural growth combined with being the global hub of oil and gas industries. These economic transformations are associated with release of air pollutants including urban air toxics (UAT) through industrial, traffic, and constructional activities into ambient urban environments. UAT concentrations levels may exacerbate in most MENA countries considering high number of vehicular traffic populations and petrochemical industries which are one of the main sources of this pollutant. Therefore, the main objective of the study is to review major findings of UAT levels in urban areas across thirteen (13) MENA countries. The study characterizes various measured UAT, assesses their concentrations in ambient environment, and identifies their major sources of emissions by reviewing more than 100 relevant UAT papers across the selected MENA countries. It was found that benzene, heavy metals, formaldehyde, and dioxin-like compounds are the most reported UAT. The study concluded that road traffic, fuel stations, and petrochemical industries were identified as the main sources of ambient UAT levels. It was further reported that most of the studies were based on short-term ambient environment with limited studies in indoor environments. Therefore, it is highly recommended that future research should focus on innovative health impact assessment and epidemiological studies from exposure to UAT levels. Also embarking on sustainable mitigation approaches through urban greenery, eco-industrial estates infrastructural developments, and renewable energy shares will reduce UAT levels and improve human health.

Groundwater contamination in the Gulf Cooperation Council (GCC) countries: a review.

Groundwater quality levels are currently deteriorating in Gulf Cooperation Council (GCC) countries due to excessive surface and subsurface human activities. Agricultural and industrial activities, landfill seepage and seawater intrusion have been attributed to the deterioration of groundwater quality in GCC states. Such a deterioration of groundwater quality could affect water security in the region, including human health and the ecosystem. Therefore, this review aims to identify the key causes of groundwater contamination across the GCC countries from the published literature. In addition, the review summarizes the major components of the groundwater contaminants across the GCC countries. The results have shown that heavy metals, several cations and anions are the leading cause of groundwater pollution. In most cases, the level of metals and ion contaminants exceeds both the local and international water quality standards. The results have observed the presence of high levels of coliform and radioactive elements in groundwater, especially Uranium and Radium, thereby posing additional risk to human health through consumption. Considering the scarcity of freshwater resources in GCC, urgent actions are required from the decision-makers and relevant regulatory bodies to set up and implement long-term mitigation strategies and stringent policies that will protect the groundwater resources from the adverse effects of anthropogenic activities.

Potential of dates (Phoenix dactylifera L.) as natural antioxidant source and functional food for healthy diet.

Date fruit is well known for their taste and concentrated nutritional components. Present study investigated two Omani date varieties i.e., Umsellah and Khalas, related to their physical traits, antioxidant properties, carbohydrates and nutritional values. Results showed that total-phenolic in Umsellah were 62% higher compared to Khalas, i.e., 164.22 and 103.85 mg/100 g. Among antioxidants, gallic acid in both Umsellah and Khalas were 35.77 and 27.41 mg/ 100 g respectively. Caffeic and syringic acid resulted 50% greater in Umsellah compared to Khalas. The ρ-coumaric acid contents in Umsellah and Khalas were 24.94 and 21.69 mg/ 100 g respectively. Total sugar in Umsellah (51.37 g of glucose equivalent / 100 g of dates) was found higher compared to Khalas (44.78 g of glucose equivalent / 100 g of dates). Among nutrients, potassium (K) level is very high (> 450 mg/100 g) in both the varieties with optimum range of other nutrients. For dietary fibers, Umsellah (81.17 g/100 g) reported higher proportion than Khalas (67.35 g/100 g). Overall findings inferred that Umsellah contained greater amount of beneficial individual phenolic and sugar compounds for the nourishment of health than Khalas. Therefore, as high antioxidant and nourished with several nutritional components, Umsellah and Khalas can be well adopted as organic and medicinal diets and can be used for various by-products irrespective of their market value.