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The goal of the conducted experiment was to determine the electric current impact on the efficiency of nitrogen compounds oxidation at COD to total Kjeldahl’s nitrogen ratio of 20, 10, 5. The experiments were run in bench scale, in a rotating electro-biological contactor (REBC) under both, conventional conditions (i.e. without electric current) and with electric current passage at the following densities: 0.2 A m⁻², 0.8 A m⁻², and 1.5 A m⁻². The cathode comprised stainless steel discs with immobile biofilm, and the anode a stainless steel electrode, submerged in waste water contained in the flow-tank of the contactor. The process of nitrogen oxidation was the most effective with electric current passage at the density of 1.5 A m⁻² regardless of applied COD/NTK ratio.
The efficiency of organics and nitrogen removal from municipal landfill leachate in activated sludge operated as single and two-stage SBR were investigated. Leachate from mature landfills are characterized by high N/COD ratio (> 0.5). In single activated sludge system at the hydraulic retention time (HRT) 3d and at methanol dosage 8 mg COD/mg NNO3 complete ammonium nitrogen removal was obtained. Ammonium concentration in the effluent was 0.15 mg NNH4/dm3 and nitrate - 23.5 mg NNO3/dm3 . At the hydraulic retention time 2d, nitrate nitrogen concentration in the effluent decreased to 2.79 mg NNO3/dm3. The concentration of ammonium nitrogen was 0.35 mg NNH4/dm3. However, a sporadically high concentration of ammonium appears. In a two-stage SBR system, HRT 2d was sufficient to achieve complete nitrification. In the effluent ammonium and nitrate concentrations were 0.08 mgNNH4/dm3 and 320 mgNNO3/dm3, respectively. In the anoxic reactor at HRT 1d and methanol dosage 3.6 mg COD/mg NNO3 complete denitrification was obtained. Raw leachate contained specific hazardous organics, among others BTEX (175.8 µg/dm3), chloroorganics (55.7 µg/dm3), chlorobenzenes (0.75 µg/dm3) and PAHs (1.97 µg/dm3). In the effluent from single and two-stage SBR systems chloroorganics and chlorobenzenes were not detected. BTEX and PAH concentrations in the effluent from two-stage system were adequately 2-fold and 2.1-fold lower in comparison to a single one. Besides, the effluent from two-stage SBR systems did not contain benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene and indeno(1,2,3-cd)pyrene.
The aim of this study was to investigate efficiency of ammonium nitrogen removal from municipal landfill leachate in activated sludge in two-stage SBR reactors. Treated leachate contains low concentrations of organic substances measured as chemical oxygen demand (COD) - 757 mg O2/dm3 and high concentrations of ammonium - 362 mgNNH4/dm3. Nitrification was studied in two parallel, aerated SBR reactors with two different hydraulic retention times (HRT), 3 and 2 days, respectively. We have found that 2 days HRT was sufficient to achieve complete nitrification. In the effluent ammonium, nitrite and nitrate nitrogen concentrations were 0.08 mgN NH4/dm3, 0.04 mgN NO2/dm3 and 320 mgN NO3 /dm3, respectively. The ammonium nitrogen removal rate was 20.2 mgN NH4 /dm3.h. The effluent from aerobic reactors (HRT 2 days) was fed to the anoxic SBR reactors. An external carbon source (methanol) was added to promote denitrification. In the anoxic reactor, at a methanol dosage 3.6 mg COD/mg N NO3 and HRT of 1 day complete denitrification was achieve with nitrate nitrogen residual concentrations of 0.9 mgNNO3/dm3. The maximum denitrification rate was 48.4 mgN NOx/dm3.h. The highest values of the yield methanol coefficient Y m/N-NOx were determined for dosages 3.6 mg COD/mg NNO3 and 5.4 mg COD/mg NNO3, the lowest for 1.8 mg COD/mg NNO3.
In the present study the bacterial community structure in a sequencing batch reactor (SBR) operating in autotrophic conditions was determined in relation to temporal variations of NH₄-N, NO₂-N, NO₃-N levels in the effluent. Bacterial richness and composition were determined by PCR-DGGE (Polymerase Chain Reaction - Denaturing Gradient Gel Electrophoresis) of 16S rRNA and amoA genes, and RISA (Ribosomal Intergenic Spacer Analysis) technique. The applied approaches revealed that the composition of bacterial population in the studied SBR varied in time. A positive correlation between Shannon index of ammonia-oxidizing bacteria (AOB) diversity and ammonia level in the effluent was observed. The variation of total bacterial diversity did not reflect the changes in nitrification efficiency.
8
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Nitryfikacja w glebie zanieczyszczonej miedzia

63%
W doświadczeniu laboratoryjnym badano przebieg procesu nitryfikacji w glebie zanieczyszczonej miedzią. Testowano następujące zmienne: 1) pH gleby: 7,0 i 6,0; 2) dawkę Cu w mg·kg⁻¹ gleby: 0, 300 i 600; 3) dawkę N w mg·kg⁻¹ gleby: 0 i 250; 4) czas inkubacji gleby w dniach: 0, 20, 40 i 60. W wyniku badań stwierdzono, że proces nitryfikacji był bardziej hamowany przez obniżone pH gleby niż zanieczyszczenie miedzią. Efektywność nitryfikacyjna w glebie o pH 6,0, niezanieczyszczonej miedzią, wynosiła 0,88% N·d⁻¹, a w glebie o pH 7,0 - 5,53% N·d⁻¹. Efektywność tego procesu w glebie o pH 6,0, zawierającej 600 mg Cu·kg⁻¹, wynosiła 0,36% N·d⁻¹, a w glebie o pH 7,0 - 5,36% N·d⁻¹.
Our research determined the impact of operational conditions on the quantity of total and ammonia-oxidizing bacteria (AOB) in immobilized biomass. The experiment was conducted for two kinds of wastewater differing in organic carbon concentration at HRTs of 1.5 h, 1.0 h, and 0.5 h. The evaluation of bacteria number was accomplished by using the real-time PCR targeting ammonia monooxygenase (amoA) and 16S rDNA genes. In the absence of organic carbon in the influent, the shortening of HRT from 1.5 h to 0.5 h positively affected the AOB number in immobilized biomass, which reached even 30%. But their activity was limited. In the presence of organic carbon in the influent, the shortening of HRT below 1.5 h resulted in a decline of the abundance of ammonia-oxidizing bacteria and nitrification efficiency.
W niniejszej pracy przedstawiono wyniki badań dotyczące wpływu związków ropopochodnych (olej napędowy i benzyna bezołowiowa) w glebie zasolonej NaCl na przebieg procesu nitryfikacji. Zastosowano zanieczyszczenie gleby NaCl w następujących stężeniach: 10, 100 i 1000 mmol·kg⁻¹. Kontrolę stanowiła gleba bez dodatku soli. Podwójny stres antropogeniczny otrzymano zanieczyszczając próbki z powyżej przygotowanych kombinacji olejem napędowym oraz benzyną bezołowiową w następujących dawkach: 0,1; 1 oraz 10% wag. Zasolenie gleby NaCl i jednoczesne zanieczyszczenie jej produktami ropopochodnymi wpływa niekorzystnie na przebieg procesu nitryfikacji w glebie, obniżając jego wartość. Wielkość tych zmian zależy od rodzaju i dawki wprowadzonego zanieczyszczenia. Benzyna bezołowiowa działa bardziej niekorzystnie na przebieg procesu nitryfikacji w glebie zasolonej szczególnie o zmniejszonej zawartości substancji organicznej, natomiast zaolejenie gleby zmniejsza toksyczne działanie NaCl.
The paper presents results of two year field and laboratory investigations of a denitrifying system below leach lines. More than two days retention time was provided by siphoning of the denitrifying trough located 35 and 60 cm under the leach lines. Due to clogging and capillary suction in medium sand the seepage flow through the denitrifying troughs was limited to less than 10 % of the sewage inflow. Average efficiency of the total nitrogen removal was equal to 55 % after 3-4 days of travel time within the soil. To force wastewater to pass through the anaerobic bed within the trough two lateral vertical impermeable membranes are recommended.
Nitrifying activity in the surface water of the Włocławek Dam Reservoir (WDR) was determined by use of a nitrification selective inhibitor (ATU). The highest values of nitrification were observed in the stations nearer the dam, with lower flow velocity, where the activity amounted to up to 120 µg N/dm3/day. Nitrification process [%] involvement in biochemical oxygen demand increased with passing from lotic to lenitic conditions and reached maximum values up to 70% or even 100% BOD5. Chemoautotrophic nitrifiers participation increase in oxygen consumption in the reservoir was probably caused by sedimentation of allochtonous, easily decomposable organic matter and a significant reduction in carbonaceous oxygen demand (C–BOD). Ammonium ion release from sediments was the decisive factor of shallow flooding nitrification.
Intensity of ammonification, nitrification (NH4-N oxidation to N02-N) and denitrification (reduction of NO3-N to NO2-N) was studied in soils experimentally contaminated with oil and control soils. Studies were carried out on 144 experimental plots of total area 1 ha. Half of the plots were cultivated in the usual way, the other half - intensively. Each of the 2 combinations comprised plots fertilized only with NPK, NPK and manure, and with NPK, manure and additionally inoculated with bacteria - decomposing petroleum hydrocarbons. Rye, barley, a mixture of legumes and cereals, and potatoes were cultivated in all plot combinations. Intensity of ammonification, nitrification and denitrification was determined in soil samples collected in spring, 24 months after soil contamination with petroleum. Ammonification was most intensive in soil samples collected from plots polluted with crude oil, fertilized with NPK and manure, inoculated with bacteria strains decomposing petroleum, in which rye was cultivated. NH4-N oxidation to N02-N was most intensive in soil samples collected from plots which had not been contaminated with oil, fertilized with NPK and manure, in which potatoes were cultivated. The highest reduction of N03-N to NO2-N was observed in soil polluted with oil, fertilized with NPK, in which potatoes were planted and cultivated in the usual way.
18
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Reakcja mikroorganizmów glebowych na Reglone 200 SL

51%
W doświadczeniu polowym określano zmiany zachodzące w środowisku glebowym pod uprawą dwóch odmian rzepaku ozimego: Casoar i Californium po zastosowaniu preparatu Reglone 200 SL. Gleba należy do czarnych ziem właściwych (WRB-Mollic Gleysols) o pH = 6,1. Przeprowadzone badania wykazały, że zastosowany środek chemiczny Reglone 200SL używany powszechnie w ochronie roślin wraz z upływem czasu naruszał równowagę biologiczną gleby, czego przejawem był spadek liczebności badanych grup drobnoustrojów. Termin analiz miał istotny wpływ na wzrost aktywności urolitycznej gleby oraz na istotny spadek aktywności proteolitycznej. Zastosowany herbicyd nieistotnie modyfikował procesy amonifikacji i nitryfikacji, a użyte w doświadczeniu odmiany rzepaku determinowały różnice w liczebności bakterii o uzdolnieniach proteolitycznych oraz aktywności proteazy.
The study presented in this paper was conducted under the conditions of a field experiment. Microbiological analyses were made at various stages of winter wheat plants developmentie heading, milk ripeness and full ripeness. The objective of the study was to acquire knowledge on the effect of cultivation of various lines of winter wheat on the numbers of bacteria and fungi with proteolytic capabilities, on protease and urease activity, and on the rate of the processes of ammonification and nitrification. The results of conducted study demonstrated that the number of proteolytic bacteria and fungi, as well as the activity of protease and urease, and the intensity of ammonification and nitrification processes in soil depended on both the development stage and cultivated line of winter wheat.
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