An integrated technique using solar and evaporation ponds for effective brine disposal management

Desalination is a process that involves the removal of salts and non-ionic minerals from seawater to produce freshwater that is fit for human consumption. This process produces brine, which is typically redisposed into the sea. The relatively high salt concentration in the disposed brine increases the salinity of water and soil, which adversely affects the environment. However, brine is found to be rich in economically valuable minerals. In order to effectively manage the disposed brine, this study proposes an integrated technique using solar and evaporation ponds to filter valuable minerals from concentrated brine. The results of this study demonstrate that the proposed technique can be effectively employed for this purpose. Furthermore, this helps reduce desalination costs and complies with the notion of renewable energy production and eco-friendliness

Comparison of geotube and stone cemented wall stability as coastal protection system [case study and 2D limit equilibrium and FEM modeling analysis]

Geosynthetic structures for shore protection have demonstrably lower construction and lifetime costs than those of hard structures. This paper outlines the effect of scouring on banks protection structures stability in case of comparison between sand-stone wall and a geosynthetic structure that is commonly used for shore protection: geotextile wraparound revetments (GWRs). Different 2D Limit Equilibrium and FEM modeling analysis were carried out on a case study of sandstone example. As a result, GWRs have been shown to adapt extremely well against differential settlement and scour erosion. Analyses show that many advantages of sand-stone structures remain, but that geosynthetic structures should not be regarded as an alternative shore construction method. Rather, they are a preferable solution for numerous coastal problems

Analysis of Longitudinal Cracks in Crest of Doroodzan Dam

Doroodzan earth dam is located in 85 km north western of Shiraz. Because of the unusual seepage flow in the left abutment, in 1992 an impermeable vane was grouted there. Soon after that, obvious changes in water Table profile occurred and simultaneously some incremental number of cracks in left abutment crest was appeared. In present study seepage through left abutment has been analyzed by considering water Table changes. Different phreatic surface line was carried out from recent 20 years in order to find the most vulnerable one. In addition, Seismic loading used to get proper perception of seismic stability. First, by gathering data from piezometric head through the left abutment, most critical phreatic line in left abutment section of dam was observed. Then by using present phreatic surface in numerical modeling of critical section in the left abutment of dam, long term stability of downstream in different situation were calculated. The conditions were changed by increasing the saturation zone and the time which saturation zone stay through the downstream body

Groundwater quality assessment of Labuan Island using GIS

Groundwater has been considered as an important source of water supply due to its relatively low susceptibility to pollution in comparison to surface water, and its large storage capacity (US EPA 1985). It should be mentioned that water pollution is any chemical, physical or biological change in the quality of water that has a harmful effect on any living thing that drinks or uses or lives (in) it. When humans drink polluted water it often has serious consequences on their health. Water pollution can also make water unsuited for the desired use. In present study different water quality parameters were observed from the different monitoring wells through the Labuan Island. Then by interpolation between the available data different water quality parameters maps were created. Each map is classified based on the Malaysia water quality standards. Results show those areas which are susceptible to groundwater contamination

Study on water quality parameters of Linggi and Melaka rivers catchments in Malaysia

The Linggi and Melaka rivers catchments are among the most significant watersheds in the west coast of Peninsular Malaysia. However, Malaysia is a tropical country with approximately similar seasonal climate, in the monsoon period, water level of catchment is different. Recently in the supposed domain, due to raising the population and expanding urban areas, demand for water consumption is increased gradually. On the other hand, problem of water pollutions due to industrial activities have been signed out. Therefore, study on water quality and sources of pollutions in these regions became vital for public and private sections. This study was conducted to assess the water quality conditions in both rivers catchments. The observed water quality data for 5 years period (2004-2008) were obtained from Departments of Environments’ water quality monitoring stations in Malaysia. Statistical analyses have been carried out on three water quality constituents which are BOD5, NH3-N and TSS. The observed data were compared with the water quality criteria to identify the water quality violation level in both river catchments. Furthermore, the differences in water quality between base and storm flow events were examined using Box and Whisker Plots. Results of this study indicate that TSS and NH3-N are the primary causes for water quality impairment in Linggi River with concentration of about 78.3% and 81.8% respectively. However, for Melaka catchment, TSS is identified as the main cause of water quality impairment, when 64.4% of the total water samples exceed the standard. There are some point sources and non-point sources of water quality impacts in both watersheds. The results of this study would be contributed to development of best management practices for the Linggi and Melaka catchments and similar study areas

Effects of drying and salt extraction of Moringa oleifera on its coagulation of high turbidity water

Moringa oleifera (M.O.) has been used as a natural coagulant in water treatment. The present study aims to determine the effect of drying M.O. seed powder that has been extracted with salt (NaNO3) on the coagulation of synthetic (kaolin) water of 200±5 NTU. The optimum quantity of M.O. was 5 mg for both 10 and 200 g/l concentrations of the non-spray-dried salt-extracted M.O. (MOC-SC) solutions, with turbidity removal of 87%. This maximum turbidity removal was achieved with 1 M and 0.5 M of NaNO3 salt in the former and latter concentrations, respectively. The spray-dried M.O. (MOC-SC-SD) solutions exhibited better maximum turbidity removal of more than 95%, which also occurred at 5 mg of M.O., for both concentrations. Finally, the duration of storage of MOC-SC-SD did not affect its performance in the removal of turbidity

Experimental study of tsunami bore induced forces on vertical seawall

Field surveys of the 2011 Tohoku Tsunami reported massive failures of many seawalls and coastal barriers. The massive damages are vivid evidence that there are flaws in the design of seawalls and barriers. With this as the background, a sequence of laboratory experiments using dam-break waves was performed to simulate the interactions between the tsunami-like bore flow and vertical seawall as well as to measure the bore-induced pressures and to estimate forces exerted on the vertical seawall model. The experimental result revealed that the maximum pressure (approximately 8 kPa) exerted on the vertical seawall was measured at the lowest pressure sensor location. Experimental data were used to re-examine the relevant empirical formulae found in the literature. The obtained results could be useful for calibrating mathematical and numerical models as well as for future research concerning the design of tsunami barriers

Influence of diversion angle on water and sediment flow into diversion channel

Accumulation of the sediment in the stream of the diversion channels adversely affects its operational systems. Diversion channels are often constructed perpendicular to the main river. In this study, the water flow and sediment transport in the diversion channel with different angles were investigated in an attempt to maximize water discharge and minimize sediment discharge. A physical model with movable bed was used to simulate water and sediment flow with five diversion angles (θ) between (30°–90°). Moreover, three bed width ratios (Br) (the relation between diversion to main channel bed width) between 30% and 50% and five total discharges between (7.25 L/s to 12.25 L/s) were considered for each case of (θ). The results showed, up to 10%, increasing in proportion discharge ratios for 30 and 45 diversion angles compared with 90° diversion angle. The results also showed that the lowest diversion sediment concentration was provided by the (θ) of 30°. Across all scenarios, the average proportion concentration reduction was 64%, compared with 90° diversion angle. Closer observation of the diversion system mechanism confirmed that decreased (θ) result in decreased sediment concentrations in the diversion channels. In conclusion, the diversion channel water and sediment discharge could be effectively managed by changing the (θ) to 30° or 45° instead of 90°

Preventing landslides in times of rainfall: case study and FEM analyses

Purpose: The purpose of the paper is to present a new method of controlling through susceptible slopes in order to reduce the risk of landslides. Design/methodology/approach: Geotechnical and geological characteristics were collected and different FEM analyses were carried out in a case study of the Alasht valley in Northern Iran in order to determine susceptibility to landslides and consider appropriate countermeasures. Gravel drain piles have a real feel of reducing the pore water pressure in times of seismic loading, so they are used as a remediation method. The results clearly show their effects and an increase in safety as a result. Findings: Since the water table situation has a significant effect on stability, the present study focused on an example of using a seepage controlling system and its effect on the safety factor for different slopes in the area of Alasht, Northern Iran. Several FEM analyses were carried out on a landslide susceptible case. The results from FEM analysis of different slopes in the study area show a high susceptibility to landslides for six sites. Installing a gravel drain pile surrounded by a non-woven geotextile layer leads to an increase in the safety factor against landslides. As a result, after installing gravel drain piles in the upper parts of slopes in order to control run out and ground water rising up in times of heavy rainfall, the safety factor against landslides in both static and seismic loading improved significantly. Originality/value: The literature regarding controlling seepage in order to reduce the risk of landslides is limited. This paper collects and analyses geotechnical and geological data from the Alasht valley as an example to show the high risk of susceptibility to landslides

Effect of the packaging and storage conditions on the coagulation activity of spray-dried salt-extracted Moringa oleifera

Moringa oleifera is one of the natural coagulants considered as an alternative to synthetic coagulants. Several studies were carried out on the usage and extraction of this natural coagulant. In this study, the coagulation activity of spray-dried salt-extracted M. oleifera seeds powder was investigated under different storage conditions, packaging forms and storage duration. The spray-dried salt-extracted M. oleifera seeds powder was stored at room temperature (29°C) and refrigerator temperature (3°C); under different packaging forms; closed container and vacuum packed stored for 6 weeks. Optimization of spray-dried salt-extracted M. oleifera shows that the optimal dosage is half of the nonspray-dried salt-extracted M. oleifera. The results of residual turbidity of different packaging and storage conditions of salt-extracted M. oleifera show that there was no significant difference between them. The coagualtion activity decreased insiginficantly with the increase of storage duration during the study