Cometabolic biodegradation of chlorinated ethenes with methanotrophs in anaerobic/aerobic simulated aquifer

Aim: This study explores anaerobic/aerobic biodegradation efficiencies of aerobic cometabolism with methanotrophs when contaminants trichloroethylene (TCE) and cis-1,2-dichloroethylene (cDCE) are present individually or in tandem. Methodology: Batch tests and an anaerobic/aerobic column system were used to simulate saturated, contaminated aquifers. A brown glass bottle with an effective volume of 44 m l-1 was prepared for the batch test. An integrated one-dimensional sequential anaerobic/aerobic column system was used to simulate the accumulative intermediates such as TCE, cDCE and VC caused by incomplete degradation of PCE during the upgradient anaerobic stage in the saturated aquifer. In the downgradient aquifer, aerobic cometabolism was employed to degrade the intermediates. Methanotrophs in the aerobic aquifer were inoculated to degrade the by-products of incomplete degradation of PCE by aerobic cometabolism. Results: In the batch test, biodegradation of TCE was significantly inhibited by cDCE. However, biodegradation of cDCE was not significantly inhibited by TCE. In the simulated aquifer test, aerobic cometabolism completely degraded intermediates (TCE, cDCE, and VC) produced by incomplete anaerobic degradation of tetrachloroethylene (PCE). The results showed that methane, a by-product of anaerobic reductive dechorination of PCE, was used as a primary substrate for aerobic degradation, at a utilization rate of almost 100%. Interpretation: Biodegradation of TCE was significantly inhibited by cDCE. Bioremediation should have sufficient oxygen and methane at aerobic stage to ensure that chlorinated ethenes fully mineralize.

Caracterização Hidrogeológica do Aquífero Freático da Unidade 3 da Univiçosa

Diante do avanço das simulações de águas subterrâneas nos últimos anos como forma de propor soluções para gestão de recursos hídricos, a presente pesquisa teve como objetivo a elaboração de um modelo hidrogeológico conceitual para o aquífero freático da Unidade 3 da Univiçosa, em que foi analisado o rebaixamento do nível de água do lençol freático através dos dados de bombeamento dos poços existentes no local e obtidos os parâmetros hidrodinâmicos do aquífero através do software Aquifer Test. Também foram realizadas análises potenciométricas dos poços bem como a relação entre a precipitação e a recarga do aquífero por intermédio de campanhas de monitoramento dos níveis de água estático e dinâmico dos poços e do regime de precipitação da região no intuito de se compreender o comportamento do lençol freático da região. Foi verificado que houve diferentes respostas ao bombeamento para os poços denominados “Frente Esquerda” e “Fundos Direita”, este último devido a um pequeno lago em sua proximidade. Durante a recuperação ambos os poços se comportaram de maneira semelhante em que os níveis de água atingiram valores acima dos medidos antes dos testes de bombeamento, porém com o poço “Fundos Direita” atingindo valores muito acima, por volta de 1,75 m a mais do que o nível medido antes do teste de bombeamento. Os valores dos parâmetros hidrodinâmicos encontrados foram: Transmissividade (T) 1,0 x 10-3 m2/s, Condutividade Hidráulica (K) 4,17 x 10-5 m/s e Armazenamento (S) 1,0 x 10-4. Estes valores permitiram a obtenção do Raio de influência dos poços sendo possível constatar a não sobreposição dos cones de rebaixamento entre os poços “Frente Esquerda” e “Fundos Direita”. A análise potenciométrica permitiu verificar o comportamento do fluxo de água entre os poços, incluindo um terceiro denominado “Residencial”, sendo constatado que em regime estacionário a água flui dos poços de maior para os de menor cota altimétrica e em regime transitório, quando há bombeamento, ela flui em direção aos poços. A análise da relação entre a precipitação e a recarga do aquífero não foi significativa, mostrando pequenas variações nos níveis estáticos da água dos poços em períodos chuvosos, o que leva a crer que a quantidade de água precipitada e o período de monitoramento não foram suficientes para constatar alterações nos níveis de água do lençol freático. Por fim, foi constatado que a explotação de água dos poços não compromete a quantidade de água no local, visto que não há interferência entre eles, porém recomenda-se a execução de sondagens nas proximidades dos poços para melhor caracterização dos mesmos e ampliação do período de monitoramento para melhor conhecimento do comportamento do aquífero freático local por meio da elaboração de um modelo hidrogeológico matemático.

Groundwater flow at the Rock Garden test site

<p><span>Understanding of </span><span>subsurface </span><span>flow and transport is of major interest supporting optimal design for several societal relevant technologies, such as waste disposals, geothermal or groundwater production facilities. To advance measurement and modeling techniques and refine them for practical applications, we develop the fractured aquifer test site Rock Garden at the Martin-Luther University Halle.</span></p><p> </p><p><span>The Rock Garden test site is situated beneath the courtyard of the Faculty of Natural Sciences III and is 60 m x 60 m in size. Fractured Rotliegend series of konglomerates, sand- and siltstones are investigated at the site by 6 drillings. A central borehole (B3) is 40 m in depth and developed as an open borehole between 15 m – 40 m below surface. Five boreholes are developed as groundwater observation wells of about 20 m depth and are equipped with filterscreens between 10 m - 20 m below surface. Natural groundwater levels are on average about 3 m below surface and vary about 0,5 m around this value.</span></p><p> </p><p><span>A first p</span><span>umping test in B3 unraveled hydraulic connection to all of the five surrounding boreholes. </span><span>The effective t</span><span>ransmissivities are of the order of 10<sup>-5</sup> m<sup>2</sup>/s and </span><span>storativities are of the order 10<sup>-3</sup>. </span><span>To understand hydraulically active fractures or fracture zones </span><span>and their connection to the rock matrix </span><span>at the Rock Garden site, we </span><span>plan to </span><span>performed </span><span>a first </span><span>flowmeter experiment in well B3 under natural and pumping conditions. </span><span>Finally </span><span>we plan to characterize these fractured zones in detail perform</span><span>ing</span><span> hydraulic and tracer tomography at the Rock Garden test site </span><span>in the near future.</span></p>

Analytical Solutions for Steady-State Multiwell Aquifer Tests in Rectangular Aquifers by Using Double Fourier Transform: A Case Study in the Ordos Plateau, China

Straightforward solutions have long been expected for the analysis of multiwell aquifer tests. In this paper, we derive series analytical solutions of steady-state groundwater flow in a rectangular-shaped aquifer with pumping/injection wells for both confined and unconfined conditions. Double Fourier Transform (DFT) technique is applied to deal with different combinations of impermeable and specified head boundaries on sides. The obtained solutions are compact and concise in mathematics and flexible in terms of well number, well locations, and pumping/injection rates. Hatoucaidang, a groundwater resource field in the Ordos Plateau, Northwestern China, is introduced as a field case study, where a multiwell aquifer test was conducted. One of the analytical solutions derived herein is used to estimate hydraulic conductivities by applying a direct calculation method and a least square estimation method regarding observed versus calculated drawdowns. By comparing with nearby single-well pumping tests, the reliability of the derived analytical solutions is proven. This study facilitates utilizing the multiwell aquifer test to analyze the general behavior of groundwater movement in aquifer systems.

INTERPRETASI TRANSMISIVITAS UNTUK ANALISA POTENSI AIR BAWAH TANAH BERDASARKAN DRAWDOWN AIR SUMUR CINCIN MENGGUNAKAN METODE PUMPING TEST DI KECAMATAN MARPOYAN DAMAI KOTA PEKANBARU

The most consumption water is groundwater taken through excavated wells or ring wells. An aquifer test can be applied in pump test in order to find transmissivity of drawdown ring wells.The tested ring wells were located at 25 different locations in the Marpoyan Damai District. In the pumping test on the ring wells data was obtained namely drawdown test data s, times t, rate of discharge Q, and then create a graph of s/Q vs Q. The straight line that cut the s/Q axis the A value with the C gradient and the determinant coefficient d2. The values obtained were then inserted into the transmisivity formula of the Cooper-Jacob method. The A values for t = 3 minutes and t = 7 minutes were selected because their results in C values are close to each other. The C values of t = 3 minutes and t = 7 minutes are 0.1671 and 0.1672 respectively. Transmissivity value obtained is 134.5 m2/day. The value shows a potentially useful groundwater aquifer for the Marpoyan Damai district because the transmissivity value exceeded 50 m2 / day.