Atrazine biodegradation potential in a created wetland

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Treatment of sanitary sewer overflow with fixed media bioreactors

Fixed media bioreactors (biofilters) are a promising and proven technology used for wastewater treatment in unsewered rural areas. As an on-site treatment system, it cart potentially provide high treatment efficiency with a relatively low cost and maintenance. This research expanded the application of fixed media bioreactors and tested their feasibility in the treatment of sanitary sewer overflows (SSO) at high hydraulic loading of 0.2 m/h. Sand, peat, and textile (felt) were used as media to treat simulated 6-h peak flows for a 25-year SSO event in the city of Columbus, Ohio. The influent SSO was a mixture of primary sludge from a wastewater treatment plant diluted with tap water. The efficiency of treatment was measured as changes in the concentrations of biochemical oxygen demand (BOD5), chemical oxygen demand (COD), and total suspended solids (TSS). Sand as a filter medium had the best removal of organic matter with average 84% reduction of BOD5 and 90% of COD. The TSS removal was more than 90% in all media. Peat and felt were,somewhat more efficient than the sand in the TSS removal. The media type and influent BOD5 concentration were two major factors that impacted the treatment of BOD5 (p<0.007). For the treatment of COD, significant factors were media type, influent concentration, and time course of loading in each SSO event (ps <= 0.001)

Selection for novel, acid-tolerant Desulfovibrio spp. from a closed Transbaikal mine site in a temporal pH- gradient bioreactor

Almost all the known isolates of acidophilic or acid-tolerant sulphate-reducing bacteria (SRB) belong to the spore-forming genus Desulfosporosinus in the Firmicutes. The objective of this study was to isolate acidophilic/acid-tolerant members of the genus Desulfovibrio belonging to deltaproteobacterial SRB. The sample material originated from microbial mat biomass submerged in mine water and was enriched for sulphate reducers by cultivation in anaerobic medium with lactate as an electron donor. A stirred tank bioreactor with the same medium composition was inoculated with the sulphidogenic enrichment. The bioreactor was operated with a temporal pH gradient, changing daily, from an initial pH of 7.3 to a final pH of 3.7. Among the bacteria in the bioreactor culture, Desulfovibrio was the only SRB group retrieved from the bioreactor consortium as observed by 16S rRNA-targeted denaturing gradient gel electrophoresis. Moderately acidophilic/acid-tolerant isolates belonged to Desulfovibrio aerotolerans - Desulfovibrio carbinophilus - Desulfovibrio magneticus and Desulfovibrio idahonensis - Desulfovibrio mexicanus clades within the genus Desulfovibrio. A moderately acidophilic strain, Desulfovibrio sp. VK (pH optimum 5.7) and acid-tolerant Desulfovibrio sp. ED (pH optimum 6.6) dominated in the bioreactor consortium at different time points and were isolated in pure cultur

Identifying main uncertainties in estimating past and present radiative forcing of peatlands

ABSTRACT Reconstructions of past climate impact, i.e., radiative forcing (RF), of peatland carbon (C) dynamics show that immediately after peatland initiation the climate warming effect of CH4 emissions exceeds the cooling effect of CO2 uptake, but thereafter the net effect of most peatlands will move towards cooling, when RF switches from positive to negative. Reconstructing peatland C dynamics necessarily involves uncertainties related to basic assumptions on past CO2 flux, CH4 emission, and peatland expansion. We investigated the effect of these uncertainties on the RF of three peatlands, using either apparent C accumulation (aCAR), net C balance (NCB), or NCB plus C loss during fires as basis for CO2 uptake estimate; applying a plausible range for CH4 emission; and assuming linearly interpolated expansion between basal dates, or comparatively early or late expansion. When we factored that some C would only be stored temporarily (NCB and NCB+fire), the estimated past cooling effect of CO2 uptake increased but the present-day RF was affected little. Altering the assumptions behind the reconstructed CO2 flux or expansion patterns, caused the RF to peak earlier and advanced the switch from positive to negative RF by several thousand years. Compared to NCB, including fires had only small additional effect on RF lasting less than 1000 yr. The largest uncertainty in reconstructing peatland RF was associated with CH4 emissions. As shown by the consistently positive RF modelled for one site, and in some cases for the other two, peatlands with high CH4 emissions and low C accumulation rates may have remained climate warming agents since their initiation. Although uncertainties in present-day RF were mainly due to the assumed CH4 emission rates, the uncertainty in lateral expansion still had a significant effect on the present-day RF, highlighting the importance to consider uncertainties in the past peatland C balance in RF reconstructions.Reconstructions of past climate impact, that is, radiative forcing (RF), of peatland carbon (C) dynamics show that immediately after peatland initiation the climate warming effect of CH4 emissions exceeds the cooling effect of CO2 uptake, but thereafter the net effect of most peatlands will move toward cooling, when RF switches from positive to negative. Reconstructing peatland C dynamics necessarily involves uncertainties related to basic assumptions on past CO2 flux, CH4 emission and peatland expansion. We investigated the effect of these uncertainties on the RF of three peatlands, using either apparent C accumulation rates, net C balance (NCB) or NCB plus C loss during fires as basis for CO2 uptake estimate; applying a plausible range for CH4 emission; and assuming linearly interpolated expansion between basal dates or comparatively early or late expansion. When we factored that some C would only be stored temporarily (NCB and NCB+fire), the estimated past cooling effect of CO2 uptake increased, but the present-day RF was affected little. Altering the assumptions behind the reconstructed CO2 flux or expansion patterns caused the RF to peak earlier and advanced the switch from positive to negative RF by several thousand years. Compared with NCB, including fires had only small additional effect on RF lasting less than 1000 year. The largest uncertainty in reconstructing peatland RF was associated with CH4 emissions. As shown by the consistently positive RF modelled for one site, and in some cases for the other two, peatlands with high CH4 emissions and low C accumulation rates may have remained climate warming agents since their initiation. Although uncertainties in present-day RF were mainly due to the assumed CH4 emission rates, the uncertainty in lateral expansion still had a significant effect on the present-day RF, highlighting the importance to consider uncertainties in the past peatland C balance in RF reconstructions.Peer reviewe

Seikkailukasvatuksen vaikutukset luokan ryhmäilmiöihin

Tiivistelmä. Kandidaatintutkielmamme tarkastelee systemaattisen kirjallisuuskatsauksen muodossa kotimaista ja kansainvälistä tutkimuskirjallisuutta seikkailukasvatuksesta ja ryhmäilmiöistä. Tavoitteenamme on selvittää, millaisia vaikutuksia seikkailukasvatuksella on luokan ryhmäilmiöihin. Käsittelemme tutkimuksen aikana seikkailukasvatuksen käsitteellisiä ja historiallisia taustoja sekä siihen liitettyjä oppimiskäsityksiä. Lisäksi selvennämme seikkailukasvatuksen ja elämyspedagogiikan välistä käsitteellistä yhteneväisyyttä. Perehdymme myös ryhmäilmiöiden moniulotteiseen ja jatkuvasti muuttuvaan luonteeseen. Seikkailukasvatusta voidaan pitää vaihtoehtoisena toiminnallisena opetusmenetelmänä, jossa korostuu osallistujien aidot elämykset ja kokemukset. Perusopetuksen opetussuunnitelman (2014) ja seikkailukasvatuksen oppimiskäsitykset yhdistyvät toisiinsa. Seikkailukasvatusta voidaankin hyödyntää perustellusti koulun opetuksessa. Opettajan täytyy kuitenkin huomioida toimintaa järjestäessään turvallisuusnäkökulmat, jotta oppilaat kokisivat elämykset mielekkäiksi. Kasvatuksellisesta näkökulmasta matalankynnyksen seikkailukasvatustoiminta soveltuu parhaiten koulun tavoitteisiin. Tutkimuksen edetessä vertasimme ja arvioimme jatkuvasti tutkimuskirjallisuutta kriittisesti ja pyrimme liittämään tutkimuksen tulokset suomalaiseen yhteiskuntaan ja koulujärjestelmään. Havaitsimme tutkimuksen aikana, että luokka on ryhmänä jatkuvasti muutoksen kohteena. Siihen vaikuttavat samanaikaisesti fyysinen ympäristö, sosiaalinen ympäristö, yksilöiden ominaisuudet, ryhmäsuhteet ja ryhmäprosessit. Seikkailukasvatuksella voidaan kehittää luokan ryhmädynamiikkaa ja ryhmän kiinteyttä. Lisäksi pienryhmä soveltuu erityisen hyvin seikkailukasvatuksen välineeksi, koska pienryhmässä jäsenet pystyvät vaikuttamaan ryhmän toimintaan tehokkaammin. Pienryhmätoiminta tukee myös yksilön sosiaalisten taitojen kehittymistä

Atrazine fate processes in a constructed emergent marsh: 1998research updates

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Smoking status and abdominal obesity among normal- and overweight/obese adults : Population-based FINRISK study

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