Effects Of Water Quality Changes Research Articles

Effects of water quality changes on the Ostracoda (Crustacea) species diversity and seasonal occurrence patterns in Lake Eğirdir (Isparta, Turkey)

Effects of water quality changes on the Ostracoda (Crustacea) species diversity and seasonal occurrence patterns in Lake Eğirdir (Isparta, Turkey)

Water Quality Change Due to the Mine Backfilling and Its Possible Response to Talc Flotation

A study was carried out in the framework of international R&D Project to determine the effect of water quality changes due to mine backfilling on talc flotation performance. The influence of two types of cemented paste backfill (Shotcrete and backfill) on flotation process water was investigated using the indoor soaking method, and the water quality was evaluated through water chemistry analysis, in addition to measuring pH, conductivity, and zeta potential as a function of soaking time. At the same time, talc batch flotation tests were performed using a KHD Humboldt Wedag lab cell for a period of 20 minutes. Soaking water at different soaking times was used as a process water for flotation, and tap water was also used to establish a reference response. Based upon the experimental results from the talc flotation and the several water quality parameters measured in the soaking water, conclusions were drawn.

Measuring the Productive Efficiency of the Connecticut Long Island Lobster Sound Fishery Using a Novel Finite Mixture Model

When vessel-level data and input prices are unobserved, estimating the effect of water quality changes on fishery performance can be challenging. To address this problem, we develop a novel production function model with technical efficiency (TE) under the assumption that there are multiple groups within the fishery with different levels of TE and the allocation of fishers into these groups is unknown. The methodology is applied to the Connecticut Long Island Sound lobster fishery. Two groups of fishers were identified to operate at different TE levels (0.88 and 0.74) between 1998 and 2007. The difference in TE is primarily explained by total fishing days and the number of fishers, though environmental variables also have some impact. These findings have important implications for policies geared toward improving efficiency in fisheries and accurate assessment of the overall health of marine fisheries.

High spatio-temporal variability in Acroporidae settlement to inshore reefs of the Great Barrier Reef.

Recovery of coral reefs after disturbance relies heavily on replenishment through successful larval settlement and their subsequent survival. As part of an integrated study to determine the potential effects of water quality changes on the resilience of inshore coral communities, scleractinian coral settlement was monitored between 2006 and 2012 at 12 reefs within the inshore Great Barrier Reef. Settlement patterns were only analysed for the family Acroporidae, which represented the majority (84%) of settled larvae. Settlement of Acroporidae to terracotta tiles averaged 0.11 cm-2, representing 34 ± 31.01 (mean ± SD) spat per tile, indicating an abundant supply of competent larvae to the study reefs. Settlement was highly variable among reefs and between years. Differences in settlement among locations partly corresponded to the local cover of adult Acroporidae, while substantial reductions in Acroporidae cover caused by tropical cyclones and floods resulted in a clear reduction in settlement. Much of the observed variability remained unexplained, although likely included variability in both connectivity to, and the fecundity of, adult Acroporidae. The responsiveness of settlement patterns to the decline in Acroporidae cover across all four regions indicates the importance of supply and connectivity, and the vulnerability towards region-wide disturbance. High spatial and temporal variability, in addition to the resource-intensive nature of sampling with settlement tiles, highlights the logistical difficulty of determining coral settlement over large spatial and temporal scales.

Effects of water quality changes on performance of biological activated carbon (BAC) filtration

Biological activated carbon (BAC) filtration is an important treatment step in the production of drinking water especially if drinking water is produced from surface water. The performance and processes within a BAC filter have been of interest for researchers since the 1980’s, mainly because of its ability to remove natural organic matter known as disinfection precursors. A malfunction of one of the pre-treatment steps might affect the feed water quality into the BAC filters. The main objective of this study was to determine the immediate response of the BAC filters to a rapid change in feed water quality. It was shown that with the studied setup it was possible to compare the effect of different pre-treatment steps and subsequent different water qualities on the performance of the BAC filters on the long term adaptation. However, especially the immediate response was not studied in detail before. All filters were able to mitigate a sudden change in feed water quality, either through improved adsorption or increased activity of the biomass on the filter. As a result of this resilience against sudden changes, it is therefore concluded that there is no direct need for very stringent on-line monitoring and continuous adjustments of the feed water quality of the BAC filters. The addition of phosphate resulted in the lowest dissolved organic carbon (DOC) concentration in the effluent of the BAC filters. In this study the influence of intact cells in the feed water on the performance of the BAC filters was shown to be limited.

Effects of water quality changes on the recreation benefits of swimming in Finland: Combined travel cost and contingent behavior model

Abstract Finland is a highly coastal country with a large archipelago area and numerous lakes. Consequently, these provide an essential environment for water-based outdoor recreation activities. To improve the information base for evaluating the welfare effects of policy instruments addressing water quality, such as the EU Water Framework Directive, this study examined the effects of changes in water quality on the recreation benefits, focusing on swimming trips in Finland. National recreation inventory data were used to provide information on welfare changes at the national level. The combined travel cost and contingent behavior approach revealed that the recreation value of a swimming trip in the current state was approximately 16 euros. The approach allowed assessment of the welfare effects of water quality changes beyond the observed levels, showing that a hypothetical decrease in water quality to a level at which the water visibility would be less than 1 m and abundant slime would exist decreased the value to 9 euros. Water quality improvement to a level at which the perceived water visibility would be over 2 m and no slime would exist increased the value per trip to 22 euros. In total, the overall annual value of all visits made for swimming in the case of water quality improvement increased the recreation benefits by 53–80%, while a deterioration in quality decreased the benefits by approximately 80%.

Severe Weather Effects on Water Quality in Central Arizona

Extreme weather events affect surface water supplies. Water quality measurements in Central Arizona were used to quantify changes in dissolved organic carbon (DOC) and turbidity following dust storms, floods, and drought‐associated wildfires. This article describes specific extreme events, quantifies changes in DOC and turbidity, and discusses the effects of water quality changes on treatment processes and public perceptions of water quality. Study findings show a co‐occurrence of some dust storm events (high particulate matter) and increased surface water turbidity, attenuation of high DOC loads following upper watershed storm events, significant increases in total organic carbon and turbidity following severe flooding in 2005, and differing effects of upland and lowland wildfires on water quality. Finally, a means to mitigate these effects on both perceived and actual water quality by integrating information from radar systems, stream gauge readings, and online water quality analyzers is suggested.

Effects of water quality changes on phytoplankton and lesser flamingo Phoeniconaias minor populations at Kamfers Dam, a saline wetland near Kimberley, South Africa

Kamfers Dam, a wetland near Kimberley, South Africa, supports a population of Near Threatened lesser flamingos Phoeniconaias minor. The cyanobacterium Arthrospira fusiformis (Voronikhin) Komarek and Lund 1990, the flamingos’ food source, was in bloom in April 2009. The city's wastewater treatment plant discharges partially treated and untreated sewage directly into Kamfers Dam, creating elevated water levels, poor water quality and hypereutrophication. Subsequently, a crash in the A. fusiformis population compromised the lesser flamingos’ food source. The water quality and algal community of Kamfers Dam were monitored using historical water quality data plus water quality analyses from 2009 to 2011. Conductivity, pH, sodium, chloride and total dissolved salts showed significant decreases over time. Spearman rank correlation was used to measure relationships among physico-chemical parameters and densities of algae. Arthrospira fusiformis was positively correlated with conductivity (Spearman ρ = 0.561, p = 0.029), total dissolved salts (Spearman ρ = 0.572, p = 0.026) and negatively correlated with total phosphorus (Spearman ρ = −0.718, p = 0.003). While significant correlations were found, attempts to develop a model for predicting algal community composition were unsuccessful due to strong multicollinearity among the water chemistry parameters.

Adapting water treatment design and operations to the impacts of global climate change

It is anticipated that global climate change will adversely impact source water quality in many areas of the United States and will therefore, potentially, impact the design and operation of current and future water treatment systems. The USEPA has initiated an effort called the Water Resources Adaptation Program (WRAP) which is intended to develop tools and techniques that can assess the impact of global climate change on urban drinking water and wastewater infrastructure. A three step approach for assessing climate change impacts on water treatment operation and design is being persude in this effort. The first step is the stochastic characterization of source water quality, the second step is the application of the USEPA Water Treatment Plant model and the third step is the application of cost algorithms to provide a metric that can be used to assess the coat impact of climate change. A model has been validated using data collected from Cincinnati’s Richard Miller Water Treatment Plant for the USEPA Information Collection Rule (ICR) database. An analysis of the water treatment processes in response to assumed perturbations in raw water quality identified TOC, pH, and bromide as the three most important parameters affecting performance of the Miller WTP. The Miller Plant was simulated using the EPA WTP model to examine the impact of these parameters on selected regulated water quality parameters. Uncertainty in influent water quality was analyzed to estimate the risk of violating drinking water maximum contaminant levels (MCLs).Water quality changes in the Ohio River were projected for 2050 using Monte Carlo simulation and the WTP model was used to evaluate the effects of water quality changes on design and operation. Results indicate that the existing Miller WTP might not meet Safe Drinking Water Act MCL requirements for certain extreme future conditions. However, it was found that the risk of MCL violations under future conditions could be controlled by enhancing existing WTP design and operation or by process retrofitting and modification.

Nitrogenous Compounds and Oxygen Concentration as the Key Density Dependent Factors to Optimize Growth of Beluga, <I>Huso Huso</I> (Actinopterygii: Acipenseriformes: Acipenseridae), in Circular Fiberglass Tanks

Background. Beluga, Huso huso, known also as the great sturgeon, is a valuable fish in terms of meat and caviar production. It has been implicated that intensive f ish culture is a major culprit for deterioration of water quality through metabolic excretion of fish in the aquatic environment. The aims of this study were: to determine the effect of the stocking density on the water quality, to assess the effect of water quality changes on growth of bel- uga juveniles, and also to determine the optimum density for culture in fiberglass tanks. Materials and methods. Fish were randomly distributed into 15 tanks at 5 different densities including 1 kg ·m -2 (3.90 kg m -3 ), 2 kg ·m -2 (7.09 kg ·m -3 ), 4 kg ·m -2 (14.54 kg ·m -3 ), 6 kg ·m -2 (21.19 kg ·m -3 ), and 8 kg ·m -2 (28.64 kg ·m -3 ) with 3 replicates. Specific growth rate (SGR), yield (Y), average daily growth (ADG), absolute weight gain (AWG), and relative weight gain (RWG) were calculated. Throughout the experiment, water quality parameters including ammonia (NH3), nitrite (NO2), nitrate (NO3) dissolved oxygen (DO), and oxygen saturation (OS) were also measured. Results. S tocking density considerably influences the growth of beluga juveniles and water quality during 56 days of rearing. DO, OS, NO2, NO3, and NH3 were significantly different among treatments. pH and temper- ature showed no significant effect under different stocking densities. NO2 and NO3 increased, while DO decrease as the stocking density of fish increased. At the end of the 56 days of rearing, all the growth parameters (final weight, total length, SGR, Y, ADG, AWG, and R WG) were significantly different among treatments. Survival was 100% in all of the rearing densities. Conclusion. Results of this study showed that the density of fish had a significant effect on water quality and a high density culture accompanied by intensive feeding may result in high concentrations of nitrogen com- pounds, and low concentrations of dissolved oxygen in the water of culture tanks. Each of the factors (increase nitrogenous compounds and decrease in o xygen) could suppress the growth of Huso huso juveniles.

Anticipating effects of water quality changes on iron corrosion and red water

This study investigated the effect of disinfectant, sulfate/chloride ratios, nitrate concentration, magnesium hardness and zinc on iron corrosion. For the waters tested, free chlorine better controlled red water and microbial activity in the bulk solution. Consistent with predictions based on Larson's ratio, sulfate/chloride ratio changes did not have an effect on overall iron corrosion rates, although higher chloride was associated with increased localization of corrosion and pitting. High levels of nitrate increased the rate of chlorine decay and caused release of more iron, but had no effect on chloramine decay rates. The concentration of nitrate in the water might therefore be an important factor in considering the relative merits of chloramine versus chlorine as secondary disinfectants in real distribution systems. Increased magnesium and zinc can decrease mobilization of iron (e.g. red water) caused by silicate.

Influences of Water Treatment Process on Iron and Copper Release in Distribution System

A pilot study was conducted to assess the effect of water quality changes on iron and copper release in distribution systems. Three finished waters were prepared from groundwater source by conventional treatment, lime softening and reverse osmosis (RO). To mimic desalinated seawater, sea salts were added to RO treated water. Both lime softening and RO treatment significantly decreased the calcium concentration and alkalinity of groundwater. During a yearlong investigation, the impact of seasonal changes on iron and copper release was also evaluated. The results showed that groundwater after lime softening slightly increased iron release potential but significantly decreased copper release. Desalination water caused much higher iron release but lower copper release than conventionally treated groundwater. Blended water with conventional groundwater and desalination water resulted in intermediate iron release but much high copper release. Both iron and copper release could be accelerated by temperature increase.

A method for assessing the effect of water quality changes on plumbosolvency using random daytime sampling

The Mann–Whitney U-test is used to demonstrate the impact of phosphate on lead concentrations measured at customer properties. This test is statistically robust and particularly efficient for the type of distributions encountered in lead random daytime sampling. This non-parametric technique is developed to provide a best estimate of the lead reduction that results from a change in plumbosolvency conditions. The method is illustrated with compliance data collected before and after the introduction of phosphate at customer properties in the north west of England. Limitations due to operational factors are highlighted. Using a Monte Carlo simulation of the variability of lead random daytime samples it is shown that the method might be practical when assessing the impact of incremental changes in phosphate concentration on plumbosolvency.

Corrosion control measures in Sweden and the effect of succession order

Corrosion control actions for drinking water distribution in Sweden are discussed. Several different processes are used. The water quality goals vary over a wide range both with respect to pH and alkalinity. None of the waters are supersaturated with respect to calcium carbonate. The results of the corrosion control action on copper and iron corrosion product release are calculated and discussed in terms of possibilities for improvements. The effect of water quality changes due to pipe material succession order is shown.