Environmental factors associated with the filamentous green algae Cladophora blooms: A mesocosm experiment in a shallow eutrophic lake.

The process of ecological restoration in eutrophic lakes, often results in the blooming of the filamentous green algae Cladophora. This consequently affects the growth of submerged plants and the restoration of vegetation. However, the blooming process of Cladophora and the environmental factors affecting their growth are poorly understood. This has become a difficult problem in the management of lakes. The study therefore focused on succession process of Cladophora blooms and their driving factors through mesocosm experiments in Caohai Lake. The results of our experiment indicated that Cladophora growth was mainly affected by water temperature, turbidity and soluble reactive phosphorus concentration of the habitat where Elodea nuttallii and Cladophora coexist. Nuisance Cladophora was mainly affected by turbidity (>19.24 NTU) when the water temperature was above 15.7 °C. With increasing Cladophora biomass and decreasing turbidity (<4.88 NTU), Cladophora biomass accumulation was mainly limited by the soluble reactive phosphorus concentration (<3.2 µg/L). Recorded turbidity range of 9.54-13.19 NTU was found to cause dramatic changes in the biomass of Cladophora. The results also showed that the outbreak of Cladophora blooms was mainly attributed to turbidity when the water temperature was appropriate in eutrophic lakes. These findings suggest that successful management efforts should strengthen the monitoring of transparency change in addition to controlling the phosphorus concentration to limit the Cladophora overgrowth on lake ecological restoration.

Evaluating Al-based coagulants for drinking water facilities using Jar test and CCD/RSM analysis.

This study evaluated Al-based coagulants for turbidity removal optimization in drinking water facility using Jar test and CCD/RSM analysis. The wide use of aluminum salts requires researching improved Al-based coagulants to reduce the treatment dosage. Eight polyaluminum chloride coagulants (PACl), i.e., Hyperlon 4064-PACl 2, Hyperlon 4393, 1757 X1, 1757 XL8- PACl 1, Ultrafloc 1406, Ultrafloc 3759, AlcoPAC 6, and AlcoPAC 1010 were first compared using a series of jar tests to determine the best candidate in removing the settled and filtered turbidity in water. The results showed that all PACls performed better than alum in removing water turbidity, but Hyperlon 4064 was the best. Then, the central composite design/response surface methodology (CCD/RSM) analysis was applied to Hyperlon 4064 to optimize dosage and pH to achieve the lowest final settled and filtered turbidity in the treated water, which were 21.7 mg/L, 7.53 and 27.95 mg/L, 7.91, respectively. Two quadratic models were generated by the CCD/RSM analysis with high correlations between the actual and predicted responses (R2 = 0.9881 and 0.9809 for final settled turbidity and final filtered turbidity). The results from this study can provide useful information to the operating water treatment plants that use Al-based coagulants to remove turbidity in water.

Application of an innovative water-assisted ultraviolet C light technology for the inactivation of microorganisms in tomato processing industries.

We aimed to study the efficacy of a water-assisted UVC light device (WUVC) as an innovative clean technology for the disinfection of fresh sound tomatoes and processing wash water and water turbidity was evaluated as a critical parameter. First, wash waters with different turbidities (from 0.4 to 828 NTU) were inoculated with Listeria innocua and treated in the WUVC device at different dosages. Secondly, fresh tomatoes, inoculated with L. innocua and non-inoculated ones, were treated using the WUVC device containing wash water of different turbidities for different times. The reduction of L. innocua populations on wash water and on the surface of tomato was influenced by turbidity; lower reduction values were observed at higher turbidities. Washing tomatoes with tap water with UVC lamps off (control treatment, TW) decreased L. innocua population on the surface of tomatoes but did not eliminate those bacteria that went into the water. Contrarily, when UVC lights were on, L. innocua population in wash water after treatment significantly decreased, those in clean water being the lowest populations. Reductions of native microbiota on the clean water treated with the highest UV-C radiation dose were lower than those obtained when tomatoes were artificially inoculated. We demonstrated that high reductions of L. innocua population on fresh tomatoes could be achieved using the WUVC system but some drawbacks related to the increase of turbidity should be solved for its implementation in real conditions.

Expression and secretion of active Moringa oleifera coagulant protein in Bacillus subtilis.

Cationic polypeptide proteins found in the seeds of the tropical plant Moringa oleifera have coagulation efficiencies similar to aluminum and ferric sulfates without their recalcitrant nature. Although these proteins possess great potential to augment or replace traditional coagulants in water treatment, harvesting active protein from seeds is laborious and not cost-effective. Here, we describe an alternative method to express and secrete active M. oleifera coagulant protein (MO) in Bacillus subtilis. A plasmid library containing the MO gene and 173 different types of secretory signal peptides was created and cloned into B. subtilis strain RIK1285. Fourteen of 440 clones screened were capable of secreting MO with yields ranging from 55 to 122 mg/L of growth medium. The coagulant activity of the highest MO secreting clone was evaluated when grown on Luria broth, and cell-free medium from the culture was shown to reduce turbidity in a buffered kaolin suspension by approximately 90% compared with controls without the MO gene. The clone was also capable of secreting active MO when grown on a defined synthetic wastewater supplemented with 0.5% tryptone. Cell-free medium from the strain harboring the MO gene demonstrated more than a 2-fold reduction in turbidity compared with controls. Additionally, no significant amount of MO was observed without the addition of the synthetic wastewater, suggesting that it served as a source of nutrients for the effective expression and translocation of MO into the medium.

Conservation implications of anthropogenic impacts on visual communication and camouflage.

Anthropogenic environmental impacts can disrupt the sensory environment of animals and affect important processes from mate choice to predator avoidance. Currently, these effects are best understood for auditory and chemosensory modalities, and recent reviews highlight their importance for conservation. We examined how anthropogenic changes to the visual environment (ambient light, transmission, and backgrounds) affect visual communication and camouflage and considered the implications of these effects for conservation. Human changes to the visual environment can increase predation risk by affecting camouflage effectiveness, lead to maladaptive patterns of mate choice, and disrupt mutualistic interactions between pollinators and plants. Implications for conservation are particularly evident for disrupted camouflage due to its tight links with survival. The conservation importance of impaired visual communication is less documented. The effects of anthropogenic changes on visual communication and camouflage may be severe when they affect critical processes such as pollination or species recognition. However, when impaired mate choice does not lead to hybridization, the conservation consequences are less clear. We suggest that the demographic effects of human impacts on visual communication and camouflage will be particularly strong when human-induced modifications to the visual environment are evolutionarily novel (i.e., very different from natural variation); affected species and populations have low levels of intraspecific (genotypic and phenotypic) variation and behavioral, sensory, or physiological plasticity; and the processes affected are directly related to survival (camouflage), species recognition, or number of offspring produced, rather than offspring quality or attractiveness. Our findings suggest that anthropogenic effects on the visual environment may be of similar importance relative to conservation as anthropogenic effects on other sensory modalities.

Temporal variation in methane emissions in a shallow lake at a southern mid latitude during high and low rainfall periods.

The global methane (CH4) emission of lakes is estimated at between 6 and 16 % of total natural CH4 emissions. However, these values have a high uncertainty due to the wide variety of lakes with important differences in their morphological, biological, and physicochemical parameters and the relatively scarse data from southern mid-latitude lakes. For these reasons, we studied CH4 fluxes and CH4 dissolved in water in a typical shallow lake in the Pampean Wetland, Argentina, during four periods of consecutive years (April 2011-March 2015) preceded by different rainfall conditions. Other water physicochemical parameters were measured and meteorological data were reported. We identified three different states of the lake throughout the study as the result of the irregular alternation between high and low rainfall periods, with similar water temperature values but with important variations in dissolved oxygen, chemical oxygen demand, water turbidity, electric conductivity, and water level. As a consequence, marked seasonal and interannual variations occurred in CH4 dissolved in water and CH4 fluxes from the lake. These temporal variations were best reflected by water temperature and depth of the Secchi disk, as a water turbidity estimation, which had a significant double correlation with CH4 dissolved in water. The mean CH4 fluxes values were 0.22 and 4.09 mg/m2/h for periods with low and high water turbidity, respectively. This work suggests that water temperature and turbidity measurements could serve as indicator parameters of the state of the lake and, therefore, of its behavior as either a CH4 source or sink.

Human-induced eutrophication maintains high parasite prevalence in breeding threespine stickleback populations.

Anthropogenic activities are having profound impacts on species interactions, with further consequences for populations and communities. We investigated the influence that anthropogenic eutrophication has on the prevalence of the parasitic tapeworm Schistocephalus solidus in threespine stickleback Gasterosteus aculeatus populations. We caught stickleback from four areas along the coast of Finland, and within each area from one undisturbed and one eutrophied habitat. We found the prevalence of the parasite to be lower in the eutrophied habitats at the start of the breeding season, probably because of fewer piscivorous birds that transmit the parasite. However, while the prevalence of the parasite declined across the season in the undisturbed habitat, it did less so in eutrophied habitats. We discuss different processes that could be behind the differences, such as lower predation rate on infected fish, higher food availability and less dispersal in eutrophied habitats. We found no effect of eutrophication on the proportion of infected stickleback that entered reproductive condition. Together with earlier findings, this suggests that eutrophication increases the proportion of infected stickleback that reproduce. This could promote the evolution of less parasite resistant populations, with potential consequences for the viability of the interacting parties of the host-parasite system.

Spatiotemporal variations of river water turbidity in responding to rainstorm-streamflow processes and farming activities in a mountainous catchment, Lai Chi Wo, Hong Kong, China.

River turbidity is an important factor in evaluating environmental water quality, and turbidity dynamics can reflect water sediment changes. During rainfall periods, specifically in mountainous areas, river turbidity varies dramatically, and knowledge of spatiotemporal turbidity variations in association with rainfall features and farming activities is valuable for soil erosion prevention and catchment management. However, due to the difficulties in collecting reliable field turbidity data during rainstorms at a fine temporal scale, our understanding of the features of turbidity variations in mountainous rivers is still vague. This study conducted field measurements of hydrological and environmental variables in a mountainous river, the Lai Chi Wo river, in Hong Kong, China. The study results revealed that variations of turbidity graphs during rainstorms closely match variations of streamflow hydrographs, and the occurrence of the turbidity peaks and water level peaks are almost at the same time. Moreover, the study disclosed that the increasing rates of the turbidity values are closely related to the rainfall intensity at temporal scales of 15 and 20 min, and the impact of farming activities on river turbidity changes is largely dependent on rainfall intensity. In the study area, when the rainfall intensity is larger than 35 mm/hr at a time interval of 15 min, the surface runoff over the farmland would result in higher river water turbidity downstream than that upstream. The study results would enrich our understanding of river water turbidity dynamics at minute scales and be valuable for further exploration of the river water environment in association with turbidity.

The Effect of Goldfish (Carassius auratus) on Water Quality in Horse Stock Tanks.

Goldfish (Carassius auratus) have been reported as a method to keep water tanks clean; however, little information exists on this approach. The objectives were to evaluate the efficacy of goldfish on maintaining water quality in tanks and to evaluate the frequency that this method is used. The first objective was completed during June through October 2017 in St. Paul, MN, using plastic and metal 379 L stock tanks, each with and without goldfish in a drylot that housed six adult horses. The stocking rate was 5 goldfish per tank. Daily readings of total dissolved solids (TDS) and water turbidity (NTU), and weekly samples to measure chlorophyll a were taken. At the end of each 28-day period, tanks were cleaned and rotated. Plastic tanks had lower TDS than metal tanks (P < .001); however, metal tanks had lower NTU and chlorophyll a (P ≤ .008). Adding goldfish resulted in lower TDS (P < .001); however, there was no effect on NTU or chlorophyll a (P ≥ .097). No parameters had an impact on horse preference (P ≥ .108). The second objective was completed using an online survey that was open from October 31 until December 15, 2018. Of the 672 completed surveys, 56% had not tried using goldfish in water tanks, 26% had utilized goldfish in the past, and 18% currently used goldfish. The inclusion of goldfish in water tanks did not affect all water quality parameters; however, 44% of survey respondents had tried, or were currently using, this management method.

The effects of sediment used in beach nourishment: Study case El Portet de Moraira beach.

Actions taken to prevent or reduce coastal erosion often do not have the desired effect, leading to major problems instead of solving the original one. This research focuses on why a nourished beach- with borrowed sand and 0.05% of particles <0.063 mm- causes the presence of suspended particles that are observed by beach users as turbidity. This means that the colour of the water was not its characteristic blue, even with calm wave conditions. This research involved a shoreline evolution analysis and a sedimentological study of the sand from 1977 to 2017. The results show that the turbidity episodes that occurred after the beach fill of May 2017 do not coincide with major storms that affected the beach. Furthermore, prior to this beach nourishment, even after the most important storms turbidity was not so pronounced. However, when the pre-nourishment and post-nourishment sediment are compared and analysed in detail, by studying the microstructure and morphology of the sand particles, their composition and morphology were observed to be completely different. These differences are also reflected in the accelerated particle weathering test, with the post-nourishment particles showing greater dissolution of carbonates. From its mineralogy, the post-nourishment material presents a smaller proportion of quartz in its composition and a significant amount of particles (9.6%) formed by clusters of Calcium and Silicon. The separation of this mineralogical composition produced by waves explains the formation of particles measuring <0.063 mm, a fact that has also been confirmed by the accelerated particle weathering test. This is, therefore, the cause of turbidity in the swash zone of the beach.

A novel method for extraction of a proteinous coagulant from Plantago ovata seeds for water treatment purposes.

Several chemicals have been applied in the process of coagulant extraction from herbal seeds, and the best extraction has been obtained in the presence of KCl or NaNO3[1-3], and NaCl [4]. However, the main challenge posed to these methods of coagulant extraction is their relatively low efficiency for water treatment purposes and the formation of dissolved organic matter during the treatment process. In these methods the salts, which have a one-valance metal (Na(+) and K(+)), are deposited in the internal structure and the pore of the coagulant, and may be useful for the coagulation/flocculation process. In this research, we found that modified methods produced more dense protein. Therefore, the modified procedure was better than the older one for removal of turbidity and harness from the contaminated water. Here we describe a method where: •According to the Hardy-Schulze rule, we applied the Fe(3+) ions instead of Na(+) and K(+) for the extraction of protein from Plantago ovata seeds.•The method was narrowed to extract protein by ethanol (defatting) and ammonium acetate and CM-Sepharose (protein extraction).•Two consecutive elutriations of crude extract was directly performed using 0.025-M FeCl3 and 0.05-M FeCl3 according to the basis of the ion-exchange processes.

Performance evaluation of different filter media in turbidity removal from water by application of modified qualitative indices.

BACKGROUND: Water filtration units have been faced problems in water turbidity removal related to their media, which is determined by qualitative indices. Moreover, Current qualitative indices such as turbidity and escaping particle number could not precisely determine the efficiency of the media in water filtration, so defining new indices is essential. In this study, the efficiency of Anthracite-Silica and LECA-Silica media in turbidity removal were compared in different operating condition by using modified qualitative indices. METHODS: The pilot consisted of a filter column (one meter depth) which consisted of a layer of LECA (450 mm depth) and a layer of Silica sand (350 mm depth. Turbidities of 10, 20, and 30 NTU, coagulant concentrations of 4, 8, and 12 ppm and filtration rates of 10, 15, and 20 m/h were considered as variables. RESULTS: The LECA-Silica media is suitable media for water filtration. Averages of turbidity removal efficiencies in different condition for the LECA-Silica media were 85.8±5.37 percent in stable phase and 69.75±3.37 percent in whole operation phase, while the efficiency of total system were 98.31±0.63 and 94.49±2.97 percent, respectively. CONCLUSION: The LECA layer efficiency in turbidity removal was independent from filtration rates and due to its low head loss; LECA can be used as a proper medium for treatment plants. Results also showed that the particle index (PI) was a suitable index as a substitute for turbidity and EPN indices.

Evaluación del tratamiento de agua para consumo humano mediante filtros Lifestraw® y Olla Cerámica / Evaluation of drinking-water treatment by Lifestraw® and Ceramic-pot filters

Objetivo Evaluar la eficiencia de dos sistemas de filtración casera: LifeStraw® family (FM) y Filtro de Olla Cerámica (FOC) en el tratamiento del agua para consumo humano bajo condiciones controladas de laboratorio y en términos de remoción de Turbiedad y E.coli. Métodos Ambos sistemas se operaron durante 6 meses tratando diariamente 7,5 litros de sustrato sintético. La turbiedad del sustrato se ajustó con Caolín y la concentración de E.coli con la réplica de la cepa ATCC 95922. Los resultados obtenidos en términos de remoción de turbiedad y E. coli fueron evaluados con un análisis de varianza (ANOVA) y considerando aspectos operativos y de mantenimiento. Resultados La turbiedad del sustrato sintético presentó un promedio 32,3 ± 2,8 UNT y la concentración de E. coli 3,9 x105 UFC/100mL. Ambos sistemas de filtración disminuyeron la turbiedad a niveles menores de 2 UNT y lograron la inactivación del 100 % de E.coli. Se encontraron diferencias significativas en la remoción de turbiedad siendo más eficiente el FM (99,2 % ± 0,4) que el FOC (97,6 % ± 1.14). Conclusiones Los dos sistemas de filtración son adecuados para el tratamiento del agua a nivel casero, cumpliendo con la reglamentación Colombiana. El FM resultó más eficiente en remoción de turbiedad y tasa de filtración; Sin embargo, cuando se tienen en cuenta aspectos como aceptabilidad social operación, mantenimiento y vida útil, el filtro de olla cerámica parece más apropiado especialmente en áreas rurales.(AU)

Objective To evaluate under laboratory conditions, the removal efficiency of turbidity and E. coli of two household water filters: LifeStraw® family (MF) and ceramic pot filter (CPF). Methods The two systems were operated over 6 months using two identical control units per system, treating 7.5 L/d of a synthetic substrate used as raw water. The turbidity of the substrate was adjusted with Kaolinite and the E. coli concentration, with a replica of the ATCC 95922 strain. The differences of effluent quality of the systems, in terms of turbidity and E. coli, were evaluated with Analysis of Variance (ANOVA). Operative and maintenance aspects, that could limit or enhance the use of the systems, were also considered in the evaluation. Results The water synthetic substrate quality had an average of 32.2 ± 2.8 NTU for turbidity and 3,9x105 UFC/100 mL for E. coli. Both systems reduce the turbidity to values below 2 NTU with an inactivation of 100 % of E. coli. Statistical differences were found between the systems in terms of turbidity removal, MF being more efficient than the CPF (99,2 ± 0.4 % and 97.6 % ± 1.14, respectively). Conclusions Both systems are suitable for household water supply treatment, acheiving the water quality standards established by Colombian regulations. The MF was more efficient for suspended solids removal and filtration rate, but when economic, operative, and maintenance aspects along with social acceptability and lifespan are considered, the CPF seems more suitable, especially in rural areas.(AU)