Search results for " water"
showing 10 items of 3407 documents
Sisävesien mikrotonnisto : pienet höyrylaivat Suomen ja erityisesti Kainuun sisävesiliikenteessä 1870-luvulta 1960-luvulle
2016
The significance in Finland of shipping on inland waterways has been great. This is due to the topography of the country with its many lakes and to the fact that the vast waterways in their natural state were easily navigable. The construction of canals resulted in even more extensive interconnected inland waterways. This study explores the tasks of the steamships plying these internal waterways, their numbers and significance, and also changes and the reasons for these between different inland waterways, as regards different types of vessels and shipowners in the period from the 1870s to the 1960s. Special attention is paid to steamships smaller than 19 net register tons. This limit was ch…
Face and Content Validity of the Pictorial Scale of Perceived Water Competence in Young Children
2022
An international group of experts have developed a pictorial tool to measure perceived water competence for children aged from 5 to 8 years old: the Pictorial Scale of Perceived Water Competence (PSPWC). The aim of the present study was to verify the validity of this tool. In the first part of the study, 120 children were interviewed to investigate face validity of the PSPWC to ensure that all pictorial items were understandable. In the second part of the study, 13 scientific and/or pedagogical international experts were invited to assess the tool’s content validity via an online survey. Face validity results revealed that children were able to understand and sequence correctly the aq…
Modelling the removal and reversible immobilization of murine noroviruses in a Phaeozem under various contamination and rinsing conditions
2018
International audience; Enteric viruses entering the soil with contaminated irrigation water can reach groundwater or be internalized in plants through their roots without being inactivated. Their fate in the soil depends on the virus, the soil and the soil solution. In order to write a mathematical model suitable for a Calcaric Phaeozem, we investigated the removal of murine norovirus and reversible immobilization in aggregate columns according to a saturation procedure, conditions between contamination and rinsing time, temperature and soil solution. Viruses were quantified before and after 0.45‐μm filtration with an RT‐qPCR (real‐time polymerase chain reaction). Experimental results supp…
The recent Nyiragongo (Democratic Republic of Congo) eruption: the impact of volcanic ash fallout on drinking water and edible plants
2022
Nyiragongo is an active intraplate volcano well known for its fascinating persistent lava lake inside the crater and is recognized as one of the most dangerous volcanoes in the world as more than two million people live on its slopes, 18-25 km far from the main crater. It is located in the Virunga Volcanic Province (VVP), in the western branch of the East African Rift System (EARS), at the intersection between the Democratic Republic of Congo, Rwanda, and Uganda. Unexpectedly, on 22 May 2021, Nyiragongo produced three different lateral lava flows in the low flanks and significant amounts of volcanic gas and ash were emitted from the summit crater. For several weeks, the ash fallout strongly…
Effect of temperature on anaerobic treatment of black water in UASB-septic tank systems
2007
The effect of northern European seasonal temperature changes and low temperature on the performance of upflow anaerobic sludge blanket (UASB)-septic tanks treating black water was studied. Three UASB-septic tanks were monitored with different operational parameters and at different temperatures. The results indicated the feasibility of the UASB-septic tank for (pre)treatment of black water at low temperatures with respect to removal of suspended solids and dissolved organic material. Inoculum sludge had little effect on COD(ss) removal, though in the start-up phase some poorly adapted inoculum disintegrated and washed out, thus requiring consideration when designing the process. Removal of …
Particle balance and return loops for microplastics in a tertiary-level wastewater treatment plant.
2021
Highlights: Dewatering by centrifugation was a step that removed a high number of MPs from the sludge. Sludge retained especially the fibrous microplactics. Reject water transported microplastics inside a wastewater treatment plant. Disc filter-based tertiary treatment ensured removal of 99% of microplastics in wastewater. Microplastics (MPs) from households, stormwater, and various industries are transported to wastewater treatment plants (WWTPs), where a high proportion of them are captured before discharging their residuals to watersheds. Although recent studies have indicated that the removed MPs are mainly retained in wastewater sludge, sludge treatment processes have gained less atten…
REVERSE ELECTRODIALYSIS FOR POWER PRODUCTION FROM OILFIELD WASTEWATERS
2022
Produced waters (PWs) are wastewaters generated by crude-oil extraction processes. They can present very different characteristics depending on the field location and production process. Dispersed oil, dissolved organics and solid particles are usually the main components. Moreover, PWs can contain a very high quantity of dissolved salts 1, with a total dissolved solid (TDS) concentration up to 300 g/L. Each barrel of extracted oil requires the simultaneous extraction of 3 barrels of produced water2 on average. PWs are often discharged into the sea, or sent in evaporation ponds thus leading to a dramatic environment impact3. Reinjection in the extraction well is currently the most common an…
Water quality analysis in network and private storage tanks in intermittent distribution systems
2012
In countries suffering from chronic water shortages, water distribution systems are often operated on an intermittent basis. As a consequence, the network is involved by cyclical filling and emptying periods causing water quality degradation. During the emptying period, the distribution system is unpressurised and it may occur that pollutants move into the network. Moreover, the stagnation period can promote microbial growth. For this reason water is usually heavily chlorinated in order to maintain it potable. Due to intermittent water service users acquire private tanks, which are used for collecting water during serviced periods and distributing it when public service is not available. Th…
Alternative analysis of transient infiltration experiment to estimate soil water repellency
2019
The repellency index (RI) defined as the adjusted ratio between soil‐ethanol, Se, and soil‐water, Sw, sorptivities estimated from minidisk infiltrometer experiments has been used instead of the widely used water drop penetration time and molarity of ethanol drop tests to assess soil water repellency. However, sorptivity calculated by the usual early‐time infiltration equation may be overestimated as the effects of gravity and lateral capillary are neglected. With the aim to establish the best applicative procedure to assess RI, different approaches to estimate Se and Sw were compared that make use of both the early‐time infiltration equation (namely, the 1 min, S1, and the short‐time linear…