Microplastics in Combined Sewer Overflows: An Experimental Study

One of the main sources of microplastics inside surface waters is represented by combined sewer overflows (CSOs), involving severe risks for the environment. The entry of microplastics into water bodies also depends on the characteristics of sewer diversion structures used as flow control devices. In this work, an experimental investigation was carried out to evaluate the outflow of microplastic particles, consisting of different types of nylon fibers, from a side weir located on a channel with a rectangular section. A specific methodology was developed for the fiber sampling and outflow assessment after the tests were performed. For the tested configurations, an increase in fibers discharged up to 196.15% was measured as the water flow rate increased by 62.75%, combined with an increase in the side weir length up to 40% and a decrease in the crest height up to 20%. The size and weight of the different fibers showed a low impact due to their low inertia, and their motion was governed by the water flow. An empirical equation to evaluate the fiber outflow as a function of water flow rate and side weir geometric characteristics was also proposed and calibrated for the experimentally tested ranges of the dimensionless lateral water outflow Q* = 0.51–0.83 and of the dimensionless geometric parameter S* = 0.114–0.200. These first experimental results make it possible to carry out a preliminary assessment of the impact of CSOs in terms of microplastics spilled into water bodies.

ASSESSMENT OF CHANGES IN THE HYDROGEOLOGICAL CONDITIONS CAUSED BY WET-BASED CONSERVATION OF THE STYLSKYI QUARRY OPERATED BY “DOKUCHAEVSK FLUX AND DOLOMITE COMPLEX” PJSC USING MATHEMATICAL MODELLING

Extraction of minerals significantly affects the hydrogeological conditions of the environment. Active development of mining operations in the Donbas region determined the dominant influence of technogenic changes in geological environment on the formation of modern ecological conditions in the region. This applies not only to coal mining but also raw materials extraction (dolomites, limestone) for metallurgical plants mostly by quarrying. Recently, a significant environmental problem in the region has been the mines and quarries closure, envisaged by the program for restructuring the coal industry of Ukraine. Closure of mines or quarries through wet-based conservation is the least financially expensive, although it significantly increases the technogenic load on the natural environment. The object of research involved groundwater and surface water within the area of the Stylskyi and Skhidnyi (Vostochnyi) quarries of the “Dokuchaevsk flux-dolomite complex” PJSC, as well as Kipucha Krynytsa and Shevchenkivskyi water intake structures. The goal of research was to forecast changes in the hydrogeological conditions under the influence of wet-based conservation of the Stylskyi quarry. To achieve this goal, hydrogeological methods, mathematical modelling, and expert assessments were used. Consequently, a hydrogeological model of the research area was created, its functional correspondence to the natural-anthropogenic conditions was confirmed, and calculation hydrogeological parameters were specified. As a result, the forecast of changes in the hydrogeological conditions under the influence of wet-based conservation of the Stylskyi quarry was made. In particular, the following issues were determined: the dynamics of quarry flooding; the influence of this process on changes in water inflows to the Skhidnyi (Vostochnyi) quarry, Kipucha Krynytsa and Shevchenkivskyi water intake structures; possible flooding of settlements and swamping of the research area; changes in chemical composition and groundwater salinity; time of quarry draining at various intensity of water outflow to resume mineral production in case of need. We would like to emphasize that the forecasts made should be used when designing partial or full flooding of the Stylskyi quarry.

Development of Fuzzy Based Autoregressive Moving Average Exogenous Input Model for Water Flow in Nigerian Kanji Hydro-Power Dam

Design of robust control system for any system requires model-driven approach. Therefore, it becomes imperative to develop a dynamic model suitable for controller design on safety operation of hydropower dam for power production in Kanji dam in Nigeria. Model for reservoir flow was developed in MATLAB environment using Fuzzy Based Autoregressive Moving Average Exogenous Input (FARMAX) model structure in this study. The data used for model development covered a period of ten years (2003-2013). It consists of water inflow (WI), water outflow (WO) and spillage (S). WI and S are input variables while WO was the output variable. The model obtained using the unsmoothed data with an outlier gave -14.115%, -0.302 and 610.317 for fit, R2 and RMSE, respectively. Unsmoothed data with no outlier gave -13.802%, -0.295 and 608.643 corresponding to fit, R2 and RMSE, respectively. The model obtained using the smoothed data in the presence of an outlier gave 80.533%, 0.962 and 104.113 for fit, R2 and RMSE, respectively. Smoothed data in the absence of outlier gave 81.533%, 0.962 and 99.637 for to fit, R2 and RMSE, respectively. FARMAX has the best fit value of 87.8774% when number of rules was equal to 3 with optima model order of 3 1 4 3. The model can serve as a decision support system in evaluating the optimal reservoir operation policies in real time.

Pendekatan Hidrogeomorfologi Dan Pendugaan Geolistrik Untuk Identifikasi Potensi Airtanah Di Jedong Malang

This study aims to identify the potential groundwater in Jedong, Malang, East Java. The hydrogeomorphological approach is a suitable approach to describe the relationship between hydrological and geomorphological processes on and below the earth's surface. The survey of geoelectricity complements the hydrogeomorphological approach. It will give a better description of the groundwater conditions below the earth's surface. Based on the research, there are 2 hydrogeomorphological units in the study area, which are: Volcanic Foot Valley Unit and Volcanic Foot Ridge Unit. The best groundwater potential is in Volcanic Foot Valley Hydrogeomorphological unit, namely Awar-awar Valley and Cokro Valley. The valleys are dominated by gully erosion and landslides. They have surface deposits up to a depth of 7 meters, and lots of outcrops of breccia, pumice, and andesite boulders. The valley’s springs discharge between 56 - 198 m3/day. The average infiltration rate in the valley is 1776 mm / hour, with sandy soil material. The best aquifer consisting of sandy material is more than 10 meters in depth, based on the geoelectrical survey. Water in the aquiclude layer, cannot be exploited because it is breccia and tuff material. The Sawah valley cannot be exploited further because the groundwater potential is very low. This can be identified by the thick water outflow seepage. In the Volcanic Foot Ridge Hydrogeomorphological unit, the groundwater potential is also very small. Hydrogeomorphically, water will flow down the slope to the valley. It will reduce the infiltration rate. In general, the ridge area is only used for settlement, while the slopes are used for dryland agriculture. The geoelectric analysis results show that the groundwater potential is at a depth of more than 45 meters. This research’s results show that the combination of the hydrogeomorphological approach and the geoelectric use will provide a better description of the potential groundwater.

Quantitative Inversion of Water-Inrush Incidents in Mountain Tunnel beneath a Karst Pit

Quantitative inversion of accidents is an important work of finding the cause of accidents and avoiding their recurrence. However, quantitative inversion of accidents is difficult due to the lack and limitation of accidents monitoring information. Focusing on water-inrush incidents of Jiguan Mountain tunnel, this paper proposes a set of workflows to find out the missing conditions and quantitative inversion of accidents by flow analysis and structural safety analysis on the basis of investigating the rain capacity and water outflow in water-inrush incidents. First, hydraulic boundary in water-inrush incidents is acquired by analyzing the relationship of catchment, infiltration, and accumulation of rainwater in karst pit using the flooding algorithm of ArcGIS and the topographic mapping of UAV photogrammetry. Second, the permeability coefficients of karst infiltration zone and tunnel surrounding rock are acquired by two-step decoupling and inverse analyzing the water inflow, flow rate, and interval time between rainfall and water inrush. Third, tunnel accidents of the overload of tunnel lining induced by the catchment and infiltration of karst pit under extreme rainfall conditions are numerically simulated by using FLAC. The results indicate that quantitative inversion of water-inrush incidents reveals the process and cause of accidents and provides the safety index of tunnel structure. Not only is the water-inrush incidents of karst tunnel controlled by hydrogeology conditions, but also the rainfall recharge should not be ignored.

Interaction of a Glacial Water Outflow with the Gulf Stream

<p>A popular hypothesis in paleoclimatology posits that the episodic discharges of glacial water from the Laurentide Ice Sheet (LIS) to the North Atlantic caused abrupt changes in ocean circulation and climate during the last (de)glacial periods. Implicit in this hypothesis is that the glacial water spread away from the coast and reached critical sites of deep water formation. Among the processes that could favour the offshore export of glacial water released along the eastern North American coast is the entrainment with the Gulf Stream near Cape Hatteras, where the Stream is observed to detach from the coast in the modern climate, or at other locations between Cape Hatteras and the Grand Banks of Newfoundland.</p><p>Here we investigate the fate of glacial water released in the western North Atlantic from the Laurentian Channel, which geologic evidence suggests to have been the main route of ice discharge from the Québec-Labrador Ice Dome of the LIS. To this end, we conduct numerical experiments with an ocean circulation model with eddy-resolving resolution and configured to represent the region north of Bermuda and west of the Grand Banks. Experiments with different regional sea levels are performed which correspond to different estimates of global sea level since the Last Glacial Maximum. In each experiment, glacial water in liquid form is discharged from the Laurentian Channel, providing a paleoceanographic analogue of the dam-break problem. As expected from the action of the Coriolis force and from the properties of the glacial water inflow, the discharged water turns to the right of the Channel and then produces a narrow buoyant current that flows along the coast to the southwest towards Cape Hatteras. Our presentation will focus on the interaction of this current with the Gulf Stream, particularly with its meanders and rings, and on the role of this interaction both in the seaward export of glacial water and in the modification of the Stream itself.</p>

Dynamics of spatial and temporal outflow from a soil column influenced by earthworm activity

<p>Earthworms are known as ecosystem engineers, which influence the chemical and physical properties in their own environment and thereby strongly modify soil processes. Soil structure (soil aggregates and macropores) formed by earthworms during burrowing activity may influence the soil moisture retention and water flow, enhancing infiltration into deep soil layers.</p><p>We studied the influence of anecic earthworms (<em>Lumbricus terrestris</em> fed on poplar leaves) on the spatial and temporal variability in water outflow and storage through a soil column. Therefore, we established a cylinder (30cm diameter, 50cm high) with silty loamy soil. At the bottom boundary, 15 fiberglass wicks drain the water from the soil column. With these wicks the water outflow is measured with a spatial and temporal resolution.  After an initial wetting of the soil, irrigation of the soil cylinder was done twice per week with a full cone nozzle, with an intensity of 36 mm/h and a duration of 20 minutes After 17 weeks 10 adult earthworms were added to the column. The research design consists of three phases (i) soil-filled column ( 14  weeks, with a gap of 4 weeks in the middle due to the corona lockdown) (ii) transition phase: initial earthworm activity (3 days) (iii) soil column with earthworm created structure (7 weeks).</p><p>After the experiment, the column was excavated carefully by layers of 4cm at a time. All of the earthworms were found back alive in the column. There was evidence of earthworm burrows down to 26 cm depth in the soil column, earthworm created aggregates were seen only in the top few centimeters.</p><p>We expected the outflow of water from the soil column to change due to the earthworm activity: on the one hand, the creation of macroaggregates was expected to increase the water retention in the soil, and on the other hand, the macropores were expected to create a stronger spatial variability in outflow and a more rapid reaction of outflow to the irrigation events. </p><p>We observed mainly an earlier and slightly higher peak in the total outflow of the column coinciding with an earlier and higher peak in the spatial variability in the outflow of the wicks.</p>

How much Arctic fresh water participates in the subpolar overturning circulation?

<p><span>Fresh Arctic waters flowing into the Atlantic are thought to have two primary fates. They may be mixed into the deep ocean as part of the overturning circulation, or flow alongside regions of deep water formation without impacting overturning. Climate models suggest that as increasing amounts of fresh water enter the Atlantic, the overturning circulation will be disrupted, yet we lack an understanding of how much fresh water is mixed into the overturning circulation's deep limb in the present day. To constrain these fresh water pathways, we build steady-state volume, salt, and heat budgets east of Greenland that are initialized with observations and closed using inverse methods. Fresh water sources are split into oceanic Polar Waters from the Arctic and surface fresh water fluxes, which include net precipitation, runoff, and ice melt, to examine how they imprint the circulation differently. We find that 65 mSv of the total 110 mSv of surface fresh water fluxes that enter our domain participate in the overturning circulation, as do 0.6 Sv of the total 1.2 Sv of Polar Waters that flow through Fram Strait. Based on these results, we hypothesize that the overturning circulation is more sensitive to future changes in Arctic fresh water outflow and precipitation, while Greenland runoff and iceberg melt are more likely to stay along the coast of Greenland.</span></p>