Interlobate esker aquifer characterization by high resolution seismic reflection method with landstreamer in SW Finland

The Virttaankangas interlobate esker with 100 m thick sediments has a complex depositional history. It is one of the largest groundwater reserves in Finland and hosts a managed artificial recharge plant providing potable water for the 300,000 inhabitants of the Turku region. We researched the characteristics of the esker aquifer both on a major fracture valley and on an esker ridge with a low groundwater table. This study presents the results of the first landstreamer-based high-resolution seismic reflection survey in Finland conducted in 2011. The esker core (main aquifer) position was delineated accurately throughout the entire area with continuous seismic data compared to a previous sedimentological model, gravimetric data and reference drillings. New features related to the widening of the coarse-grained unit of the esker core as well as a previously unknown daughter esker adjacent to the main esker core were revealed. These new findings are in agreement with the existing 3-D hydrogeological model. Our research provides valuable data on the high-resolution seismic reflection surveying of thick interlobate glaciofluvial deposits on two areas with differing bedrock topography on crystalline basement rocks.</p

Bacterial diversity and predicted enzymatic function in a multipurpose surface water system – from wastewater effluent discharges to drinking water production

Funding Information: The authors would like to express special acknowledgment to the CONPAT research team at the Finnish Institute for Health and Welfare, Finnish Environment Institute, and VATT Institute for Economic Research. Special thanks go to Tiina Heiskanen and Laura Wessels for extracting the nucleic acids. The Water Protection Association of the River Kokem?enjoki (KVVY) is acknowledged for surface water and wastewater sampling. Funding Information: Academy of Finland (grant number 263451) and Kaute Foundation (grant number 20190366) are acknowledged for providing funds for the project establishment and manuscript writing, respectively. Funding Information: The authors declare that they have no competing interests. This work was in part supported by the U.S. Environmental Protection Agency (EPA), and any opinions expressed do not reflect the views of the agency; therefore, no official endorsement should be inferred. Any mention of trade names or commercial products does not constitute endorsement or recommendation for use. Publisher Copyright: © 2021, The Author(s).Background Rivers and lakes are used for multiple purposes such as for drinking water (DW) production, recreation, and as recipients of wastewater from various sources. The deterioration of surface water quality with wastewater is well-known, but less is known about the bacterial community dynamics in the affected surface waters. Understanding the bacterial community characteristics -from the source of contamination, through the watershed to the DW production process-may help safeguard human health and the environment. Results The spatial and seasonal dynamics of bacterial communities, their predicted functions, and potential health-related bacterial (PHRB) reads within the Kokemaenjoki River watershed in southwest Finland were analyzed with the 16S rRNA-gene amplicon sequencing method. Water samples were collected from various sampling points of the watershed, from its major pollution sources (sewage influent and effluent, industrial effluent, mine runoff) and different stages of the DW treatment process (pre-treatment, groundwater observation well, DW production well) by using the river water as raw water with an artificial groundwater recharge (AGR). The beta-diversity analysis revealed that bacterial communities were highly varied among sample groups (R = 0.92, p = 13%) than in other groups (= 13%) than in others (Peer reviewe

Constructing a three-dimensional geologic model of the Virttaankangas Aquifer, Southwestern Finland : methods applicable to Illinois

Includes bibliographical references (p. 9)

Raw Water Quality and Pretreatment in Managed Aquifer Recharge for Drinking Water Production in Finland

The main objective of managed aquifer recharge (MAR) in Finland is the removal of natural organic matter (NOM) from surface waters. A typical MAR procedure consists of the infiltration of surface water into a Quaternary glaciofluvial esker with subsequent withdrawal of the MAR treated water from wells a few hundred meters downstream. The infiltrated water should have a residence time of at least approximately one month before withdrawal to provide sufficient time for the subsurface processes needed to break down or remove humic substances. Most of the Finnish MAR plants do not have pretreatment and raw water is infiltrated directly into the soil. The objectives of this paper are to present MAR experiences and to discuss the need for and choice of pretreatment. Data from basin, sprinkling, and well infiltration processes are presented. Total organic carbon (TOC) concentrations of the raw waters presented here varied from 6.5 to 11 mg/L and after MAR the TOC concentrations of the abstracted waters were approximately 2 mg/L. The overall reduction of organic matter in the treatment (with or without pretreatment) was 70%-85%. Mechanical pretreatment can be used for clogging prevention. Turbidity of the Finnish lakes used as raw water does not necessitate pretreatment in basin and sprinkling infiltration, however, pretreatment in well infiltration needs to be judged separately. River waters may have high turbidity requiring pretreatment. Biodegradation of NOM in the saturated groundwater zone consumes dissolved oxygen. Thus, a high NOM concentration may create conditions for dissolution of iron and manganese from the soil. These conditions may be avoided by the addition of chemical pretreatment. Raw waters with TOC content up to at least approximately 8 mg/L were infiltrated without any considerations of chemical pretreatment, which should be evaluated based on local conditions