TRIHALOMETHANES (THMs) FORMATION IN A DISTILLATION PROCESS

In this study, the fate of THMs -formation .in seawater distillation process and the rates of THMs formation in the chlorinated blended distillate were examined under various experimental conditions. The following general equation was obtained empirically: Log (THM) = _A * Log (Cl2) + B * Log (TOC) + C (THM) is the concentration of total THMs in µg/l, (Cl2) and (TOC) are the concentration of chlorine doese and total organic carbon in mg/l, A,B, and C are estimated parameters. The results showed that THMs level increases with the increase of both chlorine and initial humic substances concentrations. Increase in temperature and contact time also increased THMs concentrations. On the other hand, pre-chlorination and aeration step of the seawater resulted in a reduction of THMs concentrations in the blended distillate

TRIHALOMETHANES (THMs) FORMATION IN A DISTILLATION PROCESS

In this study, the fate of THMs -formation .in seawater distillation process and the rates of THMs formation in the chlorinated blended distillate were examined under various experimental conditions. The following general equation was obtained empirically: Log (THM) = _A * Log (Cl2) + B * Log (TOC) + C (THM) is the concentration of total THMs in µg/l, (Cl2) and (TOC) are the concentration of chlorine doese and total organic carbon in mg/l, A,B, and C are estimated parameters. The results showed that THMs level increases with the increase of both chlorine and initial humic substances concentrations. Increase in temperature and contact time also increased THMs concentrations. On the other hand, pre-chlorination and aeration step of the seawater resulted in a reduction of THMs concentrations in the blended distillate

Morphological and Chemical Properties of Particulate Matter in the Dammam Metropolitan Region: Dhahran, Khobar, and Dammam, Saudi Arabia

Characteristics of airborne particulate matter (PM) as well as its levels in air samples collected from selected sites within cities of Dhahran, Khobar, and Dammam, in the Eastern Province of Saudi Arabia, are investigated. Concentration levels of the 10 microns’ PM (i.e., PM10) are determined using the gravimetric technique. Morphological and chemical characteristics of the PM collected from the sampling cities are studied using Field-Emission Scanning Electron Microscopy (FESEM), energy dispersive X-ray (EDX), and X-Ray Fluorescence (XRF). Moreover, levels and types of hazardous materials related to these samples are assessed using Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). Results revealed that the average concentration levels of PM10 were approximately 177, 380, and 126 μg/m3 in Dhahran, Khobar, and Dammam, respectively. The structure of PM collected in Dhahran was mainly platy and rod-like shaped with a size between 2 and 6 μm, while PM collected in Khobar was mostly irregular in form, with a size range between 2 and 8 μm, and Dammam’s PM was rounded and between 1 and 3 μm in size. Both EDX and XRF results indicate relatively high weight % of C, O, Si, F, and Ca with lower weight % of Na, Mg, and K at the 3 cities. Finally, the study shows that Ba and Zn were the main trace metals associated with the collected PM in the 3 cities

Geochemical Assessment of Potential Sources for Nitrate in the Wasia Aquifer, Al Kharj Area, Central Saudi Arabia

Nitrate (NO3−) represents one of the major groundwater constituents with increasing distribution and concentration in the Kingdom of Saudi Arabia. This study aimed to determine potential sources of nitrate in the Early to Late Cretaceous Wasia aquifer system at the Al Kharj area (Central Saudi Arabia) by an integrative approach using groundwater geochemistry, nitrate isotopes (15N–NO3 and 18O–NO3), and tritium (3H) measurements. The lowest saline groundwater samples (TDS = 1400–2000 mg/L) from the peripheral zone were representative for pristine groundwater from the Wasia aquifer with nitrate concentrations below 20 mg/L and low 18O–NO3 ratios (8.7–20.6‰) but enriched 15N–NO3 values (up to 10.8‰). In contrast, 11 out of 34 analyzed water samples from irrigation wells and cattle watering wells exceeded the World Health Organization (WHO) drinking water guideline value for nitrate of 50 mg/L with maximum concentrations of up to 395 mg/L. Nitrate fertilizers and atmospheric deposition are the main sources of nitrate in groundwater in the eastern and northern sections of the study area. The combination of elevated salinities (4940–7330 mg/L), NO3 (111–395 mg/L), boron (516–1430 μg/L), and enriched 18O–NO3 (21.7–25.8‰) ratios with depleted 15N–NO3 (5.7–7.6‰) confirm the local influx of evaporated irrigation water with remnants of dissolved fertilizer into the Wasia groundwater system. There was no evidence for the influx of animal or human wastes from adjacent dairy, poultry, and housing infrastructures. Tritium concentrations below the detection limit of 0.8 TU for most borehole samples implied the absence of recent natural recharge. The estimated annual average N influx of 3.34 to 6.67 kg/ha to the Wasia aquifer requires a combination of atmospheric deposition and anthropogenic sources (mainly nitrate fertilizers) to increase the nitrogen content of the Wasia aquifer