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Two sequential batch reactors (R1 and R2) of aerobic granular sludge (AGS) were inoculated with activated sludge of different origins. The objective was to investigate the granulation and the consistency between the structure of the microbial communities (16S rRNA amplicon sequencing) in each reactor and their metabolic performance (removal of C, N, and P). Both reactors were fed with acetate-based synthetic wastewater, targeting an anaerobic-aerobic cycle reputed to favor the phosphorus- and glycogen-accumulating organisms (PAO and GAO). Stable granulation was achieved in both reactors, where, instead of PAO, the dominant genera were ordinary heterotrophic organisms (OHO) such as Thauera, Paracoccus, and Flavobacterium known for their high capacity of aerobic storage of polyhydroxyalkanoates (PHA). Generally, there was good consistency between the metabolic behavior of each reactor and the bacterial genera detected. Both reactors showed high removals of C and complete nitrification (Nitrosomonas and Nitrospira detected) but a low level of simultaneous nitrification-denitrification (SND) during the aerated phase. The latter causes that nitrates were recycled to the initial phase, in detriment of PAO selection. Meanwhile, the study showed that selecting slow-growing OHOs (with aerobic storage capacity) favors stable granulation, revealing an alternative AGS technology for C and N removal.

La linfadenitis en el Cuy –C– (Cavia porcellus) es de importancia clínica, pero su etiología y tratamientos terapéuticos siguen siendo insuficiente en el campo de la Medicina Veterinaria; por ello se planteó en identificar la etiología y su susceptibilidad antibiótica de bacterias causales de Linfadenitis cervical (LC) en C reproductoras clínicamente enfermas. Se trabajó con 50 C de raza Perú, clínicamente afectadas por esta enfermedad (25 con abscesos externos y 25 con abscesos internos). Se tomaron 25 muestras independientes mediante punción/ aspiración de los ganglios linfáticos de cada grupo. Las muestras fueron cultivadas en medios ABS, TSA, BHI, suplementados con sangre de alpaca, enriquecidos con caldo FTM e incubadas a 37 °C durante 48 horas. La identificación de las bacterias se hizo mediante caracterización morfológica, microscópica, prueba de Camp y bioquímicas. La susceptibilidad antibiótica se evaluó mediante el método Kirby-Bauer utilizando seis antibióticos usuales del mercado veterinario. Se encontraron elevadas frecuencias de Streptobacillus moniliformis (100 y 96 %), Streptococcus pyogenes (96 y 100 %) y Streptococcus zooepidemicus (96 y 92 %) con estrecha asociación entre las tres bacterias para abscesos externos e internos y con presencia de multiresistencia antibiótica a más de tres antibióticos (ampicilina, oxitetraciclina, amoxicilina, cloranfenicol), con respuesta de sensibilidad a penicilina (26-29 %) y gentamicina (23-26 %) como posible éxito terapéutico. Los abscesos subcutáneos externos e internos con LC en C evidenciaron predominancia de bacteria Gram negativas S. moniliformis, S. pyogenes y S. zooepidemicus multidrogaresistente con elevadas frecuencias. Lymphadenitis in Guinea Pig –GP– (Cavia porcellus) is of clinical importance, but its etiology and therapeutic treatments remain insufficient in the field of Veterinary Medicine, therefore the etiology and antibiotic susceptibility of bacteria causing cervical lymphadenitis (CL) in clinically ill breeding GP was investigated. It was worked with 50 Peru breed GP, clinically affected by this disease (25 with external abscesses and 25 with internal abscesses). Twenty- five independent lymph node aspiration samples were taken from each group. The samples were cultured in ABS, TSA, BHI media, supplemented with alpaca blood, enriched with FTM broth and incubated at 37 °C for 48 hours. The identification of the bacteria was done through morphological and microscopic characterization, Camp’s test and biochemistry. Antibiotic susceptibility was evaluated using the Kirby-Bauer method using six common antibiotics on the Veterinary market. High frequencies of Streptobacillus moniliformis (100 and 96%), Streptococcus pyogenes (96 and 100%), Streptococcus zooepidemicus (96 and 92%) were found, with a close association between the three bacteria for external and internal abscesses and with the presence of multiple antibiotic resistance to more than three antibiotics (Ampicillin, Oxytetracycline, Amoxicillin, Chloramphenicol), with sensitivity response to Penicillin (26-29%) and Gentamicin (23-26%) as possible therapeutic success. External and internal subcutaneous abscesses with CL in C showed predominance of Gram-negative bacteria S. moniliformis, S. pyogenes and multidrug- resistant S. zooepidemicus with high frequencies. yachayruacc@hotmail.com

El estudio de la gradación en las relaciones cotidianas entre el hombre y su contexto es el siguiente reto a abordar como eje central. La mirada interdisciplinar en la experiencia del habitar en contextos urbanos, de lo macro a lo micro a través de la arquitectura, el urbanismo y el diseño de interiores en planteamientos teóricos y prácticos, reitera la compleja tarea de plantear estrategias de diseño centradas en quien da razón al espacio habitable, es decir, el ser humano como razón de antropización del contexto natural; ese dimensionamiento que va más allá de lo cuantitativo y que tiene que ver más con sus consecuencias materiales, pero también simbólicas. Aproximaciones. Escalas de relación entre la ciudad, casa y habitación representa no sólo el trabajo constante y profundo de los autores sobre este sentido de gradación, sino además es una provocación para invitar al estudio colaborativo entre las disciplinas del hábitat en sus diversas escalas, para sugerir la reivindicación del individuo como punto central de configuración.

In this study, acetaminophen (ACT) in aqueous solution was treated with electrooxidation and photo-electrooxidation processes (PEO). An electrochemical cell was used for the treatment of different concentrations of ACT (10, 50 and 80 mg L

Molasses wastewaters (MWWs) such as baker’s yeast and distilleries effluents are usually pretreated by anaerobic, followed by aerobic biodegradation. This removes almost all the BOD, enough for meeting the current discharge standards in many low- and middle-income countries. However, as shown in the present work, the biotreated effluent still contains high levels of recalcitrant COD, color (melanoidins) and inorganic salts that end up in rivers (approx. 1000 mg/L COD, 2850 Pt–Co color units, 5000 mg/L TDS and 5400 μS/cm conductivity). To address this global problematics, and given the lack of proven cost-effective advanced treatment trains for MWW, this study assessed the performance and limits of ozonation and activated carbon (AC) adsorption (contrasting with O3 applications on raw MWW). The applied versus the reacted O3 doses were quantified, allowing also to estimate the ozone uptake rate as a new tool for characterizing the reactivity of the wastewaters. The effects of the treatments on different key parameters were studied: COD, color, aromaticity (UV254 nm), toxicity (Microtox) and biodegradability (by respirometry). O3 reduced the color (> 95%), but causing low COD mineralization (

Aqueous solutions of acetaminophen (ACT) were successfully treated using continuous solar galvanic Fenton (SGF) and galvanic Fenton (GF) processes. Definitive screening design (DSD) was used to verify the influence of several experimental parameters and their interactions, the variables were: the pH, initial ACT concentration, presence or absence of solar irradiation, and H2O2 dose. For the GF system, the maximum removal efficiencies were 64.47% for total organic carbon (TOC) and 49.83% for ACT. For the SGF process, 79.38% TOC and 100% ACT were achieved. The optimal conditions in both systems were 2.5 mM H2O2, and pH 5 at 40 min of retention time. Unlike the analogous EF and PEF processes, the GF and SGF processes do not require external energy.

The enormous environmental problems that arise from organic waste have increased due to the significant population increase worldwide. Microbial fuel cells provide a novel solution for the use of waste as fuel for electricity generation. In this investigation, onion waste was used, and managed to generate maximum peaks of 4.459 ± 0.0608 mA and 0.991 ± 0.02 V of current and voltage, respectively. The conductivity values increased rapidly to 179,987 ± 2859 mS/cm, while the optimal pH in which the most significant current was generated was 6968 ± 0.286, and the ° Brix values decreased rapidly due to the degradation of organic matter. The microbial fuel cells showed a low internal resistance (154,389 ± 5228 Ω), with a power density of 595.69 ± 15.05 mW/cm2 at a current density of 6.02 A/cm2; these values are higher than those reported by other authors in the literature. The diffractogram spectra of the onion debris from FTIR show a decrease in the most intense peaks, compared to the initial ones with the final ones. It was possible to identify the species Pseudomona eruginosa, Acinetobacter bereziniae, Stenotrophomonas maltophilia, and Yarrowia lipolytica adhered to the anode electrode at the end of the monitoring using the molecular technique.

In the present work, a laboratory scale anaerobic upflow reactor (UASB) was operated with a hydraulic retention time (6 h) and at psychrophilic temperature (< 20 oC). The UASB reactor treated wastewater from a chocolate industry with two applied organic volumetric loads (OLR apl ). Each OLR apl corresponded to an experimental stage: experimental stage I with 1.8 ± 0.8 kg soluble oxygen chemical demand ([DQO s ]/m 3 /d) and experimental stage II with 3.5 ± 0.9 kg COD s /m 3 /d. The objective of this research was to evaluate the removal efficiency of CODs (RE), biogas production (BP) and experimental cell yield ( Y exp ) within the laboratory scale UASB reactor. The control parameters monitored were pH, temperature and flow. Alkalinity, volatile fatty acids and COD s were analyzed in the influent and effluent, while suspended solids were analyzed inside the reactor and in the effluent. The RE during the steady state of the two experimental stages was greater than 90 %. The high RE obtained showed that the UASB reactor efficiently treated the industrial wastewater at low temperature with the OLR apl . BP increased when OLR apl increased (1.6 ± 0.8 and 3.5 ± 1.3 L/d of OLR apl of 1.8 and 3.5 kg COD s /m 3 /d, respectively [1 atm, 273 K]). The Y exp of experimental stage II was high (0.11 kg SSV/kg COD rem ). The high Y exp of experimental stage II could be due to the influence of psychrophilic temperature in the growth rate of anaerobic microorganisms.

Quantum dots (QDs) nanoparticles are increasingly being used for electronics devices, solar energy generation and medical imaging applications. While the new properties of nanoparticles are more and more studied, little is known about their interactions with aquatic organisms. As a primary producer, phytoplankton serves as an important component of the aquatic ecosystem. According to our bibliographic search, no reports were found on the evaluation of ecotoxicity of QDs in Pseudokirchneriella subcapitata . In this study, QDs were evaluated using ecotoxicological bioassays (cellular toxicity models and potential indicators of the impact in aquatic ecosystems) with the microalgae P. subcapitata . With ecotoxicity concentrations of 0, 1, 2, 3 and 4 nM of QDs with P. subcapitata at 96 h exposure a mean inhibitory concentration of growth (IC 50 ) of the microalgae P. subcapitata IC 50 = 1,94 nM of QDs(a) was obtained for orange fluorescence; IC 50 = 1.68 nM of QDs(r) for red fluorescence, and IC 50 = 2.03 nM of QDs(v) for green fluorescence, observing the following order of sensitivity: QDs (r) ˃ QDs (a) ˃ QDs (v). The toxicity of the QDs are evident by the type of fluorescence detected in the standard solution 4 M of QDs and 10 -1 M. The images of confocal microscopy of fluorescence showed adhesions of QDs in microalgal cells until low concentrations with high growth rates of P. subcapitata at concentrations of 1 nM compared to concentrations of 10 -1 M of QDs nanoparticles with low growth rates.

Los efluentes de reactores de tratamiento biológico contienen una mezcla heterogénea de materia orgánica disuelta (MOD), la cual es de gran importancia conocer debido al impacto que tiene sobre el proceso (calidad del efluente). En esta investigación los componentes de la materia orgánica disuelta (MOD) en un reactor batch secuencial (RBS) de lodos activados (LA) fue caracterizada usando matrices de fluorescencia excitación/emisión (EEMs, por sus siglas en inglés) para identificar actividad microbiana. El principal objetivo de esta investigación fue monitorear la transformación de la MOD dentro de un reactor de 100 L SBR de LA, el cual fue operado a un tiempo de retención hidráulico de 8 horas, siendo alimentado por agua residual cruda (diluida para elevar el pH) proveniente de la industria chocolatera. LA MOD fue monitoreada utilizando espectroscopía de fluorescencia a través de cual se obtuvieron los picos máximos en las EEMs. El análisis visual que se llevó a cabo de las EEMs mostró en el efluente pares de picos que de acuerdo con la literatura se pueden atribuir a sustancias proteicas y sustancias húmicas. Dichas sustancias no se observaron en las EEMs del influente por lo cual se atribuyen a los productos microbianos solubles generados dentro del reactor.

Applying ozone to the return flow in an activated sludge (AS) process is a way for reducing the residual solids production. To be able to extend the activated sludge models to the ozone-AS process, adequate prediction of the tri-atoms effects on the particulate COD fractions is needed. In this study, the biomass inactivation, COD mineralization, and solids dissolution were quantified in batch tests and dose-response models were developed as a function of the reacted ozone doses (ROD). Three kinds of model-sludge were used. S1 was a lab-cultivated synthetic sludge with two components (heterotrophs XH and XP). S2 was a digestate of S1 almost made by the endogenous residues, XP. S3 was from a municipal activated sludge plant. The specific ozone uptake rate (SO3UR, mgO3/gCOD.h) was determined as a tool for characterizing the reactivity of the sludges. SO3UR increased with the XH fraction and decreased with more XP. Biomass inactivation was exponential (e-β.ROD) as a function of the ROD doses. The percentage of solids reduction was predictable through a linear model (CMiner + Ysol ROD), with a fixed part due to mineralization (CMiner) and a variable part from the solubilization process. The parameters of the models, i.e. the inactivation and the dissolution yields (β, 0.008-0.029 (mgO3/mgCODini)-1 vs Ysol, 0.5-2.8 mg CODsol/mgO3) varied in magnitude, depending on the intensity of the scavenging reactions and potentially the compactness of the flocs for each sludge.

La colonización nasal de Staphylococcus aureus en el personal de salud y la contaminación de superficies hospitalarias puede preceder a la infección nosocomial. El objetivo de este estudio fue caracterizar los aislamientos de S. aureus que se encuentran en el ambiente hospitalario y en el personal de salud de un hospital de Cali. Material y Métodos: Se empleó un total de 164 muestras (86 del personal de salud y 78 de las salas del hospital). Se realizó antibiograma y se amplificó por PCR los genes mecA y agr. El S. aureus resistente a meticilina asociado al hospital (SARM-AH) o el SARM asociado a la comunidad (SARM-AC) se estableció mediante el análisis de estos genes. Resultados: El S. aureus registró un 21,3% de prevalencia, se detectó en el personal de salud (9,1%) y en el ambiente hospitalario (12,2%). El S. aureus en la unidad de cuidados intensivos fue significativo, con un riesgo mayor de tres (6,1%; OR=3,143, min=1,086, max=9,099; P=0,031). Se identificaron tres perfiles de resistencia (I, II y III), el ambiente hospitalario presentó mayor riesgo de presentar aislamientos con perfil I (20%; OR= 3,500; IC 95% min= 0,050; max = 16,430; p= 0,147). Sin embargo, los aislamientos con el perfil III con multirresistencia a los antibióticos, fueron los más prevalentes en el personal de salud (25,7%) y el ambiente hospitalario (20%).Los aislamientos SARM se encontraron colonizando al 11,4% del personal de salud y en el 17,1% de las superficies del ambiente hospitalario. Todos los aislamientos SARM fueron SCCmec tipo II, compatible con un origen hospitalario. Según el análisis del locus agr, se identificaron tres grupos agr, el 51,4% de los aislamientos pertenecen al grupo agr 1, el 22,8% al agr 2 y el 25,7% al agr 3. Conclusión: Se evidenció la presencia de SARM en el personal y en diferentes salas del hospital. Esta condición podría ser un factor de riesgo para desarrollar infecciones adquiridas en el hospital.

The objective of the present study was to determine the optimum operating temperature of laboratory-scale upflow anaerobic sludge blanket (UASB) reactors during the treatment of a chocolate-processing industry wastewater at medium applied organic loading rates (OLRappl). Four UASB reactors were operated at different temperature (15, 20, 25 and 30 °C) and three OLRappl (2, 4 and 6 kg soluble chemical oxygen demand (CODs)/(m3 d)). The flowrate and the hydraulic retention time were constant (11.5 L/d and 6 h, respectively). The monitored parameters were pH, temperature, CODs, and total and volatile suspended solids. The CODs removal efficiency (RE) and biogas production rate (BPR) were calculated. The 15 °C UASB reactor had the lowest RE (39 to 78%) due to the low operating temperature. Regardless of the OLRappl, the RE of the 20, 25 and 30 °C reactors was high and similar to each other (between 88 and 94%). The BPR of the four UASB reactors had the same behaviour as the RE (BPR of 15 °C: 0.3 to 0.5 Lbiogas/(Lreactor d) (Lb/(Lr d)) and BPR of 20, 25 and 30 °C: 0.5 to 1.9 Lb/(Lr d)).

Se experimentó con diferentes concentraciones de cloruro de magnesio (MgCl2) como coagulante para reducir el color en soluciones con colorantes comerciales: negro, azul y café. Los parámetros analizados fueron pH, color, demanda química de oxígeno ( dqo ) y sólidos suspendidos totales (sst) de acuerdo con las Normas Mexicanas. Como prueba complementaria se agregó carbón activado a las muestras para reducir el color residual después de la coagulación-floculación. La reducción de los valores de color y dqo fue mayor cuando se adicionó más cantidad de MgCl2 (1.8 g/L). Los porcentajes de reducción fueron ≥90% para el color y >50% para la dqo. Los sst aumentaron con la adición de MgCl2. El carbón activado eliminó el color residual.

The main objectives of this research were twofold: a) to evaluate the performance of a low-temperature pilot-scale upflow anaerobic sludge blanket (UASB) reactor during the treatment of a chocolate-processing industry wastewater (CIW) with high soluble chemical oxygen demand; and b) to evaluate the performance of two thermal conditioning devices (TCDs) for bioenergy recovery through the in-situ biogas use. For 275 days, the UASB reactor was operated at low temperature (17–19 °C), short hydraulic retention time (6.2 h) and variable total organic loading rate (OLRT) and soluble organic loading rate (OLRS) (10.3 ± 2.9 kg-CODΤ/m3/d and 7.9 ± 2.2 kg-CODS/m3/d, respectively). The produced biogas was burned in-situ with two TCDs, which mainly consisted of an insulated combustion chamber, a heat exchanger and a Bunsen burner. The OLRT and OLRS removal efficiencies were 59.5 ± 13.6% and 71.4 ± 13.2%, respectively, whereas the biogas production was in the range of 119–834 L/d. In-situ burning of the produced biogas with the TCDs increased the influent temperature between 0.8 and 5.8 °C, which improved the biogas production of the UASB reactor. The CIW energetic potential was calculated based on the UASB reactor operational parameters, the calorific value of methane in biogas and the daily CIW production (90 m3) of the studied factory. The estimated CIW energetic potential (13.59 MJ/m3CIW) represents a sustainable source of energy, which could be enough to satisfy the power consumption of 25–42 households in Toluca Valley Metropolitan Area, Mexico.

We present Animo, a smartwatch app that enables people to share and view each other's biosignals. We designed and engineered Animo to explore new ground for smartwatch-based biosignals social computing systems: identifying opportunities where these systems can support lightweight and mood-centric interactions. In our work we develop, explore, and evaluate several innovative features designed for dyadic communication of heart rate. We discuss the results of a two-week study (N=34), including new communication patterns participants engaged in, and outline the design landscape for communicating with biosignals on smartwatches., Comment: Journal Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies (IMWUT/UbiComp '19). Volume 3 Issue 1, March 2019. Article No. 18

Leachates, particularly those from mature landfills, are difficult to treat by biological processes because of their high toxicity and low biodegradability. Therefore, the development of new treatment technology is necessary. The treatment of landfill leachate by peroxicoagulation and solar peroxicoagulation using a batch electrolytic reactor with a Fe cathode and a Cu anode is proposed. The tested operational variables included pH (2.8 and 8.2), current density (11 and 16 mA cm−2), treatment time (5, 10, 15, 20, 25, and 30 min), and presence of solar ultraviolet (UV) light and were collected using a compound parabolic collector. The optimum conditions were a pH, current density, and treatment time of 2.8, 16 mA cm−2, and 10 min, respectively. The presence of UV did not have a significant effect. The chemical oxygen demand and biochemical oxygen demand removed were 62.3% and 55.5%, respectively. The results of UV-visible absorption, fluorescence, and Fourier transform infrared spectroscopy measurements confirm the oxidation process.

This study was motivated by surprising gaps in the current knowledge of microbial inorganic carbon (Ci) uptake and assimilation at acidic pH values (pH < 3). Particularly striking is the limited understanding of the differences between Ci uptake mechanisms in acidic versus circumneutral environments where the Ci predominantly occurs either as a dissolved gas (CO2) or as bicarbonate (HCO3-), respectively. In order to gain initial traction on the problem, the relative abundance of transcripts encoding proteins involved in Ci uptake and assimilation was studied in the autotrophic, polyextreme acidophile Acidithiobacillus ferrooxidans whose optimum pH for growth is 2.5 using ferrous iron as an energy source, although they are able to grow at pH 5 when using sulfur as an energy source. The relative abundance of transcripts of five operons (cbb1-5) and one gene cluster (can-sulP) was monitored by RT-qPCR and, in selected cases, at the protein level by Western blotting, when cells were grown under different regimens of CO2 concentration in elemental sulfur. Of particular note was the absence of a classical bicarbonate uptake system in A. ferrooxidans. However, bioinformatic approaches predict that sulP, previously annotated as a sulfate transporter, is a novel type of bicarbonate transporter. A conceptual model of CO2 fixation was constructed from combined bioinformatic and experimental approaches that suggests strategies for providing ecological flexibility under changing concentrations of CO2 and provides a portal to elucidating Ci uptake and regulation in acidic conditions. The results could advance the understanding of industrial bioleaching processes to recover metals such as copper at acidic pH. In addition, they may also shed light on how chemolithoautotrophic acidophiles influence the nutrient and energy balance in naturally occurring low pH environments.

Dynamic activated sludge modeling (ASM) and the concept of chemical oxygen demand fractionation utilized by this modeling approach suggested the existence of new strategies for minimization of excess sludge. One of these strategies consists of eliminating the traditional sludge wastage (WAS) and avoiding the buildup of inert solids in the aeration tanks by other means: fine screens are used to remove the inert particulate organic fraction (XI), hydrocyclones (HC) are used for inorganic suspended solids (ISS), and different types of online digesters are used to further biodegrade the endogenous residues (XP) via the return activated sludge (RAS) line. In this research, a model and a simulation program were developed that were able to mimic the apparent behavior of activated sludge variants with low solids production (LSP-AS). The model is an extended ASM1 assuming a small first-order biodegradation constant for XP = 0.007 d−1), and black boxes represent XI and ISS removal. The simulations first de...

Currently, the method most used for measuring the maximum specific growth rate ( μ Hmax ) of heterotrophic biomass is by respirometry, using growth batch tests performed at high food/microorganism ratio. No other technique has been suggested, although the former approach was criticized for providing kinetic constants that could be unrepresentative of the original biomass. An alternative method (seed-increments) is proposed, which relies on measuring the initial rates of respiration ( r O2 _ini ) at different seeding levels, in a single batch, and in the presence of excess readily biodegradable substrate (S S ). The ASM1-based underlying equations were developed, which showed that μ Hmax could be estimated through the slope of the linear function of r O2 _ini ·( V WW + v ML ) vs v ML (volume of mixed liquor inoculum); V WW represent the wastewater volume added. The procedure was tested, being easy to apply; the postulated linearity was constantly observed and the method is claimed to measure the characteristics of the biomass of interest.

Effluent organic matter (EfOM) from activated sludge systems is composed primarily of influent refractory compounds, residual degradable substrate, intermediate products and soluble microbial products (SMPs). Depending on operational conditions (hydraulic and sludge retention time (SRT)), the quantity and quality of EfOM significantly changes. The main objective of this research was to quantify and characterize the EfOM of a lab-scale activated sludge sequencing batch reactor (SBR), which was operated at three SRTs and fed glucose, an easily biodegradable substrate. EfOM was followed with two direct-quantification methods (chemical oxygen demand (COD) and dissolved organic carbon (DOC)), three spectrometric methods (ultraviolet absorbance at 254 nm (UVA254), excitation-emission matrix (EEM) fluorescence and parallel factor analysis (PARAFAC)) and three organic matter (OM) indices (specific UVA254 (SUVA), SUVA–COD, COD/DOC ratio). The significant increment of UVA254 and OM indices after treatment indicated an accumulation of refractory high-molecular-weight humic-like compounds in the EfOM, which demonstrated that EfOM was composed mainly by SMPs and not glucose. On the other hand, as the SRT increased, the amount of EfOM decreased, but SUVA, SUVA–COD and fluorescence intensity increased; these trends indicated the accumulation of SMPs of increased molecular weight and aromaticity. Increasing SRT in the SBRs reduced the amount of EfOM, but increased its aromaticity and reactivity. Visual analysis of EfOM EEMs showed two protein- and one humic-like peak, which were attributed to SMPs generated within the SBRs. PARAFAC determined that a two-component model best represented EfOM EEMs. The two-components from PARAFAC were mathematically correlated to the visually identified protein- and humic-like SMPs peaks.

A comparison of the metabolic potential of 20 bioleaching microorganisms and their close relatives from the Eubacteria and Archaea kingdoms permits the prediction of inter- and intra-species physiological interactions (ecophysiology) during spatial and temporal changes that are known to occur within industrial bioleaching heaps. Genome analysis has allowed preliminary models to be built for genes and pathways involved in key processes such as nitrogen and carbon cycling, sulfur and iron uptake and homeostasis, extra-cellular polysaccharide biosynthesis, heavy metal resistance and energy metabolism. This paper will focus on the diverse ways that bioleaching microorganisms obtain carbon from their environment with a particular emphasis on elucidating how these processes might be expected to vary over space and time during the lifetime of a bioleaching operation. It is anticipated that this knowledge will improve our understanding of fundamental biological processes in extremely acidic environments.