Impact of high turbidity on reverse osmosis: evaluation of pretreatment processes

This study evaluates the performance of sand filtration (SF) and ultra-filtration (UF) as pretreatment processes for reverse osmosis (RO) for seawater with turbidities of 4.8, 23.2, and 99.7 NTU. For seawater with a turbidity of 4.8 and 23.2 NTU, the average membrane flux and the water recovery rate in the RO process did not improve significantly by pretreating the seawater using SF or UF. However, when the turbidity of seawater was 99.7 NTU, pretreating the seawater with UF improved the average membrane flux and the water recovery rate in the RO process by 5 LMH and 1.7%, respectively. Pretreatment of seawater with a turbidity of 99.7 NTU with UF reduces the specific energy demand and increases the average membrane flux and water recovery rate

Comparison of Nanofiltration with Reverse Osmosis in Reclaiming Tertiary Treated Municipal Wastewater for Irrigation Purposes

This study investigates the performance of reverse osmosis (RO) and nanofiltration (NF) for the reclamation of ultra-filtered treated sewage effluent (TSE) for irrigation of food crops. RO and NF technologies were evaluated at different applied pressures, the performance of each technology was evaluated in terms of water flux, recovery rate, specific energy consumption and quality of permeate. It was found that the permeate from the reverse osmosis (RO) process complied with the Food and Agriculture Organization (FAO) standards at applied pressures between 10 bar and 18 bar. At an applied pressure of 20 bar the permeate quality did not comply with irrigation water standards in terms of chloride, sodium and calcium concentration. It was found that the nanofiltration process was not suitable for the reclamation of wastewater as the concentration of chloride, sodium and calcium exceeded the allowable limits at all applied pressures. In the reverse osmosis process, the highest recovery rate was 36% achieved at an applied pressure of 16 bar. The specific energy consumption at this applied pressure was 0.56 kWh/m3. The lowest specific energy of 0.46 kWh/m3 was achieved at an applied pressure of 12 bar with a water recovery rate of 32.7%

Evaluation of ultrafiltration and multimedia filtration as pretreatmeprocess for forward osmosis

© 2020 Desalination Publications. All rights reserved. In order to reduce scaling in a multistage flash (MSF) desalination plant, the brine reject can be diluted using forward osmosis (FO) before recycling. In this FO process, the brine is used as the draw solution (DS) and seawater is used as the feed solution (FS). However, the FO process suffers from low water flux owing to membrane fouling. The water flux in FO can be enhanced by reduc-ing the foulant concentration in the FO feed solution (FS). Thus, in this paper seawater, multimedia sand filtered seawater, and ultrafiltrated seawater is being used as feed solution for the FO process. The flowrate of the feed solution was kept constant at 2.0 L/min. However, the flowrate of the draw solution (DS) were tested at 2.0 and 0.8 L/min. When the flowrate of the DS was 0.8 L/min, the highest initial flux of 44.1 L/m2 h were obtained using ultrafiltrated seawater as FS. After the initial run, the membrane was cleaned and during the second run, 83% of the initial flux was recovered using the ultrafiltrated seawater as FS. For ultrafiltrated seawater, the water recovery rate and specific energy consumption was 36.2% and 0.065 kWh/m3, respectively

EPIDEMIOLOGIC ASPECTS OF TRAUMA IN AL-JOUF REGION, SAUDI ARABIA: A RETROSPECTIVE STUDY

Objectives: This study aimed to determine the types, characteristics, and associated factors of trauma in Al-Jouf Region which is located in Northern part of Saudi Arabia. Methods: The present study was conducted in the Emergency Department of Prince Meteb Hospital in Al-Jouf Region. A total number of 382 patients were enrolled in the present study. A pre-organized data form were designed for each patient attended the Emergency Department of Prince Meteb Hospital from January 2017 to January 2018. It included data about sociodemographic characteristics, type of trauma, and trauma characteristics. Results: The mean age of the patients was 24.4±13.4 years. Most of the patients (75%) were <30 years old. Males (86.9%) were influenced by trauma more common than females. Most of the patients (84.8%) were from urban areas. Blunt trauma constituted 58.9% while, penetrating trauma 41.1%. The most common cause of trauma was road traffic accidents, which occurred among 40% of patients. The most frequent trauma site was head trauma (49%). Most of the patients (47.9%) reached the hospital within 30 min. Regarding the fate of patients, 46.1% discharged after management, 42.1% admitted to intensive care units, and only 11.8% died. Blunt trauma was significantly higher than penetrating trauma among the young age group. Patients with blunt trauma arrived hospital significantly earlier than patients with penetrating trauma. The fate of patients is significantly better in blunt trauma than penetrating trauma. Conclusion: Trauma is considered to be a major public health problem, particularly in the young population in Saudi Arabia. Blunt trauma is more common than penetrating trauma, with road traffic accidents representing the majority