Showing papers on "Saline water published in 1998"

Saline Agriculture for Irrigated Land in Pakistan: A Handbook

Abstract: Saline agriculture is a rich collection of possible systems for the use of saline land, involving combinations of salt-tolerant trees, shrubs and crops. This handbook is written for farmers and agricultural extension officers in government and non-government organisations. The aim is to provide a simple accessible account of saline agricultural practices for irrigated land in Pakistan.

Process for desalination of saline water, especially sea water, having increased product yield and quality

Abstract: A desalination process is disclosed which combines two or more substantially different water treatment processes in an unique manner to desalinate saline water, especially sea water, to produce a high yield of high quality fresh water, including potable water, at an energy consumption equivalent to or less than much less efficient prior art desalination processes. In this process a nanofiltration step is synergistically combined with at least one of sea water reverse osmosis, multistage flash distillation, multieffect distillation of vapor compression distillation to provide an integrated desalination system by which sea water can be efficiently and economically converted to high quality potable water in yields which are at least 70 %-80 % greater than the yields available from the prior art processes. Typically a process of this invention using the nanofiltration initial step will produce, with respect to sea water feed properties, calcium, magnesium, sulfate and bicarbonate ion content reductions of 63 %-94 %, pH decreases of about 0.4-0.5 units and total dissolved solids content reductions of 35 %-50 %.

Aquatic invertebrates of Lake Gregory, northwestern Australia, in relation to salinity and ionic composition

Abstract: Lake Gregory is a large semi-permanent lake system in arid north-western Australia Its catchment extends into humid areas and as a result the lake has dried only twice in the last 25 years Although the system is mostly fresh, parts of it become saline as they dry We identified aquatic invertebrates and undertook chemical analysis of water samples from several sites at Lake Gregory in 1989, when the main water-body was saline, and in 1991 and 1993, after the system had flooded and was fresh During the period 1989–1993, salinities varied from 01‰ to 82‰, and ionic composition ranged from strong sodium chloride dominance, in saline water and fresh water of the eastern part of the system, to bicarbonate dominance in fresh water of the western area At least 174 invertebrate species were recorded, including two mollusc species that were never collected live This species richness is much higher than that recorded from other Australian arid zone lakes, probably owing to long periods of inundation with fresh water The fauna was dominated by insects (42 per cent of total species richness), crustaceans (27 per cent) and rotifers (22 per cent) Most species (160) were restricted to fresh water; only 12 species were found in saline water Only one ostracod occurred in saline conditions, although ostracods are a dominant group in Australian saline lakes Among species restricted to fresh water, the proportion of rotifer and protozoan fauna that occurred in bicarbonate-dominated water was greater than the proportion of insect, crustacean and hydracarine fauna that did so

Simulating skimming well techniques for sustainable exploitation of groundwater

Abstract: The problems of saline water upconing and intrusion are of major concern in the Indus Basin of Pakistan. The withdrawals of fresh water overlying saline groundwater have resulted in inferior quality of pumped water and degradation of the aquifer. The continuous use of such qualitatively inferior water for irrigation has severely affected fertile lands causing agro-economic declination. Nearly 197 billion cubic meters (bm3) of fresh water has accumulated in the form of a thin layer over saline water, and over 20 bm3 of fresh water is being recharged annually in saline zones of the basin. In these situations skimming wells can play an important role in augmenting irrigation supplies and watertable control, as well as alleviating degradation of the aquifer. However, the working efficiency of skimming wells is not fully known. To investigate the effectiveness of various skimming wells, a density dependent finite element numerical model was modified and applied. In the present study an analytical equation was developed by gauging the effects of temperature and viscosity on the hydraulic conductivity of the porous media subjected to the saline water. The new equation was incorporated into the model. Simulations of flow and solute transport towards single, two-strainer, radial, compound and recirculation wells were performed. Physical modelling of such skimming well configurations was undertaken to calibrate the numerical model. The double-strainer well method performed better than the other skimming configurations tested in this study.

Elimination of microcystin peptide toxins from water by reverse osmosis

Abstract: The elimination of microcystin-LR (MCYST-LR) and microcystin-RR (MCYST-RR) by reverse osmosis from tap and salt (3000 ppm NaCl) water was examined. The average retention rates for the microcystins of three different membrane types were determined by measuring the MCYST-LR and MCYST-RR concentrations in both the permeate and the retentate. The effectiveness of the reverse osmosis apparatus was assured by conductivity measurements. Using high performance liquid chromatography analysis the detection limit for both MCYST-LR and MCYST-RR was 0.2 μg/L and the quantification limits were 0.9 and 0.8 μg/L for MCYST-LR and MCYST-RR, respectively. Under the experimental conditions applied, the average retention rates for MCYST-LR and MCYST-RR in tap water were in the range of 96.7% to 99.9% and in salt water between 98.5 and 99.9%. There was no significant difference between salt and tap water for either compound. © 1998 John Wiley & Sons, Inc. Environ Toxicol Water Qual 13: 143–148, 1998

Physiological Response of Two Turfgrass Species to Varying Ratios of Soil Matric and Osmotic Potentials

Abstract: Plants grown under saline conditions can experience elevated matric and osmotic stress between irrigation events. Research was conducted to assess the physiological response of tall fescue (Festuca arundinacea Schreber 'Monarch') and common bermudagrass (Cynodon dactylon L. 'Numex Sahara') to varying combinations of soil matric (ψ M ) and osmotic potentials (ψ II ). Two line-source gradient experiments were conducted, using municipal water with an electrical conductivity (EC) of 1.1 dS m -1 or saline aquifer water blended with municipal water (EC of 6.0 dS m -1 ). Turf temperature, leaf xylem water potential (ψ L ), tissue osmolality (ψ II-TISS ), yield, evapotranspiration (ET a ), percent cover, turf color, and tissue ion concentrations were monitored during a 68-d drydown period during the summer of the second year of experimentation. The total soil water potential (ψ T ) was highly linear with distance from the line source with no significant difference between fresh and saline treatments within each species (bermudagrass, Adj r 2 = 0.867**; tall fescue, Adj r 2 = 0.810*). Significantly lower soil osmotic potentials were recorded under the saline treatment, while lower soil matric potentials were recorded under the fresh treatment for both species. Turf temperature, yield, ET a , turf color, and canopy cover responded to ψ M and ψ II in an additive fashion. The ψ L , ψ II-TISS and tissue ion concentrations in bermudagrass and ψ II-TISS and tissue ion concentrations in tall fescue responded in a nonadditive fashion, however. Out results suggest that water with a salinity level of 6.0 dS m -1 could be used as a supplemental irrigation source for both tall fescue and bermudagrass if irrigation practices were designed to minimize water deficit.

Effects of salinity and alkalinity on pansy and impatiens in three different growing media

Abstract: The quality of irrigation water used for greenhouse crop production can strongly influence plant growth. However, the effect on plant growth is probably a combination of water quality and the type of growing media used. To determine the effect of saline and alkaline irrigation water on plant growth and nutrition, pansy and impatiens were grown in peat, peat:pine bark, and pine bark media under standard greenhouse conditions. Salinity treatments of 0, 100 and OmgL‐1 NaCl: CaCl2 and alkalinity treatments of 0, 100, 200, 300, and 400 mg L‐1 NaHCO3 were applied at every irrigation. Salinity levels at 100 mg L‐1 and greater caused necrosis of leaf edges, upward curling of leaves, and reduced flower number for pansy. Treatment symptoms for impatiens were reduced growth, general chlorosis, and reduced flower number. These treatment symptoms increased in severity for plants grown in pine bark. Alkalinity levels at 200 mg L‐1 and greater caused decreased flower number, necrosis of leaf edges, and downward...

Impact of Salinity and Media on Growth and Flowering of a Hybrid Phalaenopsis Orchid

Abstract: The effects of water salinity [0.05, 0.40, 0.75, 1.10, and 1.40 dS.m -1 of electrical conductivity (EC)] on Phalaenopsis orchids grown in 100% fine-grade fir bark or a combination of 80% bark and 20% sphagnum peat were studied. In both media, flower diameter decreased slightly as salinity increased. Plants in bark had more flowers as salinity increased, but had fewer flowers than those grown in bark/peat. In either medium, salinity had no effect on the number of new leaves produced. As salinity increased, plants in bark had increasingly larger total leaf area, with a maximum at EC = 1.10 dS.m -1 . Leaf area of plants in bark/peat was greater than that of those in bark, but was unaffected by salinity. Root fresh mass was lower with increasing salinity in both media. Media had no effect on mineral concentration in the leaf. In bark, increasing salinity increased the Ca and Na concentrations but had no effect on the concentration of other minerals in leaves. As salinity increased in the bark/peat medium, leaf concentrations of P, Fe, and Cu decreased and those of K, Ca, Mg, Na, and Zn increased, but the concentration of N was unaffected by salinity. Leachate from bark/peat had twice the EC and lower pH (4.9) than bark (5.7).

Flood and salinity stress of wetland woody species, buttonbush (Cephalanthus occidentalis) and swamp tupelo (Nyssa sylvatica var.biflora)

Abstract: Buttonbush (Cephalanthus occidentalis) and swamp tupelo (Nyssa sylvatica var.biflora) seedlings were exposed to flooding and salinity conditions simulating the chronic exposure of sea-level rise and the acute exposure of hurricane storm surge. Chronically exposed seedlings were either watered or flooded with 0, 2, or 10 ppt salinity. Those in the acute experiment were watered or flooded with freshwater until exposed to a 21-ppt salinity surge for 48 hours. Freshwater flooding reduced photosynthesis (A), water pressure potential (Ψ), height, and stem and root biomass for swamp tupelo while biomass of buttonbush roots decreased and stem increased. Chronic watering with 2 ppt salinity reduced height, basal diameter, and stem and root biomass for swamp tupelo but did not significantly affect buttonbush. Both species were negatively affected by watering with 10 ppt salinity, with total mortality of swamp tupelo. Flooding with 2 ppt salinity also caused a 100% mortality for swamp tupelo. All buttonbush seedlings survived with reducedA, Ψ, and stem and root biomass. Plants chronically flooded with 10 ppt salinity were more affected, with drastically decreasedA, stomatal conductance (g s ), and Ψ within the first day of treatment and all dying within three weeks. Watering with 21 ppt salinity reducedA andg, of both species during the second day of the surge, but buttonbush recovered within the next 20 days. Flooding with 21-ppt saline water also greatly impacted buttonbush, which did not recover as when watered with 21 ppt salinity. Swamp tupelo was already stressed due to flooding and showed no further reduction in A org s due to the 21-ppt salinity flood surge. Buttonbush seedlings were more tolerant of salinity and flooding conditions than swamp tupelo seedlings, although it is unlikely that either species could survive long-term exposure to 10-ppt salinity flooding.

Is salinity the only water quality parameter affected when saline water is disposed in rivers

Abstract: The effect of saline lake water disposal from the Lough Calvert Drainage Scheme on water quality of the Barwon River, in south west Victoria, Australia, was investigated. The Scheme is used to regulate the levels of several saline lakes outside the Barwon's catchment. This study found that the disposal of saline lake water was associated with increased total phosphorus, PO4, TKN, suspended solids, electrical conductivity and stream discharge and lower NOx in the Barwon River. Thus, when disposing of saline water, factors other than salinity should be considered in order to prevent an impact on the aquatic environment. At present this is generally not done. The results are discussed with reference to the effects of saline water disposal on aquatic biota and how the effect of saline lake water disposal on water quality may differ from the disposal of saline groundwater.

Environmental impacts of deep opencast limestone mines in Laegerdorf, Northern Germany

Abstract: Deep opencast mines for limestone of Upper Cretaceous age in the northernmost state of Germany, Sch!eswig-Holstein, greatly impact the local environment. In three pits with depths of nearly 100 m, mine pumping affects deeper aquifers and sometimes shallow ones as well. The total amount of mine water pumped ranges up to 6*106 m3/year. Due to the relief of hydraulic pressure, saline water is ascending from deeper parts of the limestone and infiltrating into the pits via the minefloor. The salt content of the deep ground water exceeds that of the sea in some places. The saline water causes process engineering problems and adversely affects the water quality of a receiving channel. Shallow aquifers are affected by dewatering due to hydraulic connections to the limestone. In places with organic soils (mostly peat of Holocene age), this is followed by ground subsidence, which damages buildings and agricultural drainage systems.

Effects of coalbed methane‐produced water on sorghum‐sudangrass growth and soil chemical properties

Abstract: Production of methane gas from coal seams generates well water that is slightly to moderately saline. Since land application is a potential method of disposal for this water, a greenhouse study was...

Adverse responses in egg shell quality in late-lay resulting from short-term use of saline drinking water in early- or mid-lay

Abstract: Three experiments were carried out to determine the long-term responses in egg shell quality when hens were given saline drinking water for only a few weeks either at the start of lay or in mid-lay. Shell quality of eggs from hens given town water containing an additional 2 g sodium chloride (NaCl)/L as drinking water for periods of 5 or 6 weeks prior to 30 weeks of age or between 48 and 53 weeks of age was significantly poorer at the end of lay than shell quality of eggs from hens given town water throughout lay. Apart from these short periods of saline water supply the NaCl-treated hens received town water throughout lay. Shell defects were increased significantly after 55 weeks of age even when no apparent detrimental effects of saline drinking water on shell quality were observed during the period of saline water intake or when the incidence of shell defects returned to normal after the replacement of saline water with town water. The results indicate that the adverse effects of saline drinking water on egg shell quality is of long-term significance, being especially noticeable towards the end of lay.

Mixing Behavior of Density-Stratified Pools

Abstract: Numerous inland Australian streams contain density-stratified or saline pools. Saline pools consist of a layer of saline water underlying a layer of fresh water. They are associated with seasonal low flows and influxes of saline groundwater and have important water quality and environmental implications. A theoretical model of the dominant mixing process (flushing) associated with flows of fresh water across the top of the saline layer is presented. Laboratory results show that progressive removal of saline water from saline pools occurs because of a thin saline layer flowing up the downstream depression slope when the surface layer flows over the saline layer at a sufficiently high velocity. The behavior of this thin layer is controlled by a balance between shear and buoyancy forces that act on it. Experimental results describe the initiation of this outflow, the rate of the outflow, the composition of the outflow, and the range of scour hole geometries over which flushing is the dominant mixing process.

Salinization of shallow sandy coastal aquifers : a case study from parts of the Niger Delta region of Nigeria

Abstract: The Niger delta is the main oil producing region of Nigeria. The shoreline of the delta is arcuate shaped with a length in excess of 300 km. Behind the belt of beaches and sand ridges at the shore is a mangrove swamp from 5 km to over 50 km wide. This zone is traversed by a network of creeks with numerous small ponds and swamps. The creek density ranges from about one creek per 3 × 3 km of the land surface to over one creek per I × 1 km, and the widths range from less than 20 m (inland) to over 1000 m at the shoreline. This paper focuses mostly on the effects of this creek network on the quality of water in the adjacent aquifers. It is clear from the study that the creeks, especially within the mangrove zone, are saline with electric conductivity (EC) ranging up to 40 000 μS cm -1 and chloride concentrations ranging up to 13 000 mg l -1 . The high salinity is generally the result of daily flushing of this zone by ocean tides. Despite the dense network of saline creeks, the groundwater in adjacent shallow aquifers is generally fresh with EC less than 1000 μS cm - and chloride concentrations less than 200 mg l -1 . However, there is clear evidence of seawater presence in the shallow aquifers and some locations have up to 18% saline seawater. The low level of seawater encroachment seems to arise from the nature of the hydraulics in the area. Most of the aquifers are essentially undeveloped, in many of the rural settlements sampled, and the general flow of the groundwater is towards the creeks. It is projected that heavy groundwater withdrawal from the many water boreholes in Oil Corporation Campsites may have stimulated a more intense saline water encroachment than was observed in this study.

Persistence of Chlorpyrifos in Soil Irrigated with Saline Water

Abstract: The persistence of chlorpyrifos in soil irrigated with graded salinity levels (3.11, 5.90, 10.80 and 19.80 dSm−1) was studied under field capacity moisture regime. Chlorpyrifos disappeared faster in soil treated with normal irrigation water (0.03 dSm−1) than in soil treated with other irrigation waters of varying salinity levels. Continuous use of saline irrigation water did not influence the pH of soil, whereas the electrical conductivity increased linearly with increased levels of salinity in irrigation water.

汽水域―中海・大橋川における内部振動と貧酸素水塊の動態との関連

Abstract: Highly saline water (salinity-17 psu) in the lower layer of Lake Nakaumi often ascends along the lake bottom and flows into the Ohashi River. In this period, when the upsurge stage of internal oscillation with large amplitudes of 2-3 m appears along the western coast of the lake, a large amount of highly saline and anoxic water goes upstream through the Ohashi River. We carried out a 24- hour observation in the summer of 1996 to detect the internal oscillation and its effects on the vertical distribution of water properties, and found a dynamical relation between the internal oscillation and the anoxic water movement in Lake Nakaumi. We also performed sailing observations along the Ohashi River to examine the inflow process of anoxic water toward Lake Shinji and the dissolved oxygen consumption of the lower anoxic water. We found that the dissolved oxygen concentration showed a value below 6.0 mg 1-1 in the whole region of the Ohashi River during the observation period, and that a rapid fall in dissolved oxygen concentration did not occur while the anoxic water passed through the river from Lake Nakaumi. The lower water of Lake Nakaumi seems to recover the dissolved oxygen concentration due to vertical mixing with the upper fresh river water at the shallow eastern mouth of the Ohashi River. It then moves upstream through the river with almost no consumption of dissolved oxygen.