Isolation of microorganisms of cheese whey with lipolytic activity for removal of COD

The aim of this study was to isolate microorganisms that produce lipase and to assess the efficiency of COD removal intreatment of cheese whey under different operating conditions. The microorganisms were isolated from cheese whey and a commercial product; it was selectedthreemicroorganisms that obtained the best response to the lipolytic activity test through the enzyme index. Then, the microorganisms were inoculated in sterilized cheese whey samples, for two pH values (6.2 and 7.0), incubated at 35 °C and 150 rpm in shaker and the lipolityc activity and the efficiency of COD removal were measured in two time periods (24 and 48h). After incubation, it was observed that the treatments showed a good removal efficiency of COD for the pre-treatment and the isolated microorganism (S1) from the cheese whey showed the highest lipase production. Regarding the pH and time variables, there was not significant effect between the two evaluated factors. Among all treatments, T2 (S1, pH 7.0 and 24h) obtained more enzyme production (4.87 U mL-1).

Performance of an anaerobic-aerobic reactor and kinetic study of organic matter removal of cattle slaughterhouse effluent

This paper sought to evaluate the behavior of an upflow Anaerobic-Aerobic Fixed Bed Reactor (AAFBR) in the treatment of cattle slaughterhouse effluent and determine apparent kinetic constants of the organic matter removal. The AAFBR was operated with no recirculation (Phase I) and with 50% of effluent recirculation (Phase II), with θ of 11h and 8h. In terms of pH, bicarbonate alkalinity and volatile acids, the results indicated the reactor ability to maintain favorable conditions for the biological processes involved in the organic matter removal in both operational phases. The average removal efficiencies of organic matter along the reactor height, expressed in terms of raw COD, were 49% and 68% in Phase I and 54% and 86% in Phase II for θ of 11h and 8h, respectively. The results of the filtered COD indicated removal efficiency of 52% and k = 0.0857h-1 to θ of 11h and 42% and k = 0.0880h-1 to θ of 8h in the Phase I. In Phase II, the removal efficiencies were 59% and 51% to θ of 11h and 8h, with k = 0.1238h-1 and k = 0.1075 h-1, respectively. The first order kinetic model showed good adjustment and described adequately the kinetics of organic matter removal for θ of 11h, with r² equal to 0.9734 and 0.9591 to the Phases I and II, respectively.

Utilização de zeólita preparada a partir de cinza residuária de carvão como adsorvedor de metais em água

Coal ashes produced in coal-fired power plant could be converted into zeolites and can be used as low-cost adsorbents for the treatment of effluents contaminated with high levels of toxic metals. The capacity of synthetic zeolites for the removal of cadmium, zinc and copper ions from aqueous solutions has been investigated under different operating conditions. Zeolite from bottom chimney showed higher removal efficiency for metals ions than zeolite from feed hopper and mixing mill. The results indicated that the treated bottom ash could be applied in environmental technology as an immobilizer of pollutants.

Inativação por oxidação fotocatalítica de Escherichia coli e Pseudomonas sp.

This study presents the bactericidal activity of titanium dioxide photocatalysis, using as model Escherichia coli and Pseudomonas sp. cells. It was observed that the process efficiency is related to initial cell concentration, light intensity, UV irradiation exposure time, TiO2 concentration increase. The ultimate removal efficiency was above 99.9%.

Estudo da sorção do corante catiônico violeta cristal por espuma de poliuretano em meio aquoso contendo dodecilsulfato de sódio

This work presents a detailed study about the sorption of crystal violet (CV) cationic dye onto polyether type polyurethane foam (PUF). The sorption process was based on the formation of an ionic-pair between cationic dye and dodecylsulfate anion (SDS), which presented high affinity by PUF. Set-up employed in the study was built up by adjusting a 200 mg cylinder of PUF to the arm of an overhead stirrer. The system was characterized in relation to equilibrium and kinetic aspects and it was modeled by employing Langmuir and Freundlich isotherms. Obtained results showed that the ratio between SDS and MB concentrations played an important role on the sorption process. According to results found it was possible to retain up to 3.4 mg of dye from 200 mL of a 5.0 x 10-5 mol L-1 CV solution containing 1.25 x 10-4 mol L-1 SDS, which represented a removal efficiency of around 92%.

Descoloração redutiva de corantes azo e o efeito de mediadores redox na presença do aceptor de elétrons sulfato

We investigated the impact of sulphate and the redox mediator Anthraquinone-2,6-disulfonate (AQDS) on the decolorization of the azo dyes Congo Red (CR) and Reactive Black 5 (RB5). In anaerobic reactors free of extra sulphate dosage, the color removal efficiency decreased drastically when the external electron donor ethanol was removed. In presence of an extra dosage of sulphate, CR decolourisations were 47.8% (free of AQDS) and 96.5% (supplemented with AQDS). The decolourisations achieved in both reactors with RB5 were lower than the ones found with CR. Finally, the biogenic sulphide contribution on azo dye reduction was negligiable.

Avaliação de processo oxidativo avançado pelo reagente de Fenton em condições otimizadas no tratamento de lixiviado de aterro sanitário com ênfase em parâmetros coletivos e caracterização do lodo gerado

An alternative for landfill leachate treatment are advanced oxidation processes by Fenton's reagent (AOP/Fenton). In this context, the aim of this paper was to evaluate, in a bench scale, the treatability of leachate pós-AOP/Fenton characterizing the supernatant and the sludge generated separately. Observed in optimal conditions, high removal efficiency of COD (76.7%), real color (76.4%) and humic substances (50%). Organic compounds were detected in the sludge (2.465 mg COD L-1) and high concentration of iron (1.757 mg L-1) as was expected. Finally, the sludge generated showed low settling hindering their separation by sedimentation (SVI = 321 mL g-1).

Avaliação da remoção de fármacos e de desreguladores endócrinos em águas de abastecimento por clarificação em escala de bancada

In this work, the efficiency of clarification treatment (coagulation, flocculation and sedimentation) with polyaluminum chloride (PAC) and aluminum sulfate (SA) as coagulants was evaluated in the removal of 7 microcontaminants (diclofenac - DCF, sulfamethoxazole - SMX, ethinylestradiol - EE2, bisphenol-A - BPA, estradiol - E2, estrone - E1 and estriol - E3) in water of low and high turbidity. The clarification treatment led to poor removal rates (40% at most) for all microcontaminants except SMX which exhibited intermediate removal efficiency (67 to 70%). Overall, PAC application yielded better performance compared to SA.

Avaliação da eficiência de degradação de hidrocarbonetos aromáticos por bactérias provinientes de estação de tratamento de efluente de refinaria de petróleo

Three bacterial strains were isolated from the activated sludge system of petroleum refinery wastewater, identified by partial sequencing of 16S rDNA, and classified as Acinetobacter genomospecies 3, Bacillus pumilus, and Bacillus flexus. The degradation efficiency of aromatic hydrocarbons was evaluated by gas chromatography with a flame ionization detector. In a mineral medium containing anthracene and phenanthrene and the consortium of microorganisms, the removal efficiency was 96% and 99%, respectively, after 30 days. The good rate of hydrocarbon degradation proves the operational efficiency of the microbial consortium in treating effluents containing these compounds.

Performance evaluation of hydrocyclone filter for microirrigation

In this study a hydrocyclone filter of 20 cm was selected and its performance was evaluated by studying the variation of discharge, pressure drop, influent concentration, and filtration efficiency with elapsed time of operation. The filter was tested with clean water to determine clean pressure drop and later it was tested with four concentrations of solid suspension, viz. 300; 600; 900 and 1,200 mg L-1. In the concentration of 300 mg L-1, the variation of pressure drop was low. But for the other concentrations of solid suspension, the variation was significant. The maximum pressure drops obtained were 41.19, 45.11, 50.01 and 52.95 kPa at 350, 390, 280 and 190 minutes of elapsed time, respectively. The maximum efficiency of solid suspension was 30.3, 32.96, 43.89 and 52.5% where as the minimum efficiencies were 9.91, 9.93, 9.62 and 9.9%, respectively. The hydrociclone tested presented inefficiency to filter small particles as clay. The initial removal efficiency of higher concentration was bigger than for lower concentration but, the final efficiency are almost the same irrespective of the concentration of solid suspension. The present tested hydrocyclone could be used as a pre-filter microirrigation to prevent emitter clogging.

Start-up of horizontal anaerobic reactors with sludge blanket and fixed bed for wastewater treatment from coffee processing by wet method

In this study it was evaluated the start-up procedures of anaerobic treatment system with three horizontal anaerobic reactors (R1, R2 and R3), installed in series, with volume of 1.2 L each. R1 had sludge blanket, and R2 and R3 had half supporter of bamboo and coconut fiber, respectively. As an affluent, it was synthesized wastewater from mechanical pulping of the coffee fruit by wet method, with a mean value of total chemical oxygen demand (CODtotal) of 16,003 mg L-1. The hydraulic retention time (HRT) in each reactor was 30 h. The volumetric organic loading (VOL) applied in R1 varied from 8.9 to 25.0 g of CODtotal (L d)-1. The mean removal efficiencies of CODtotal varied from 43 to 97% in the treatment system (R1+R2+R3), stabilizing above 80% after 30 days of operation. The mean content of methane in the biogas were of 70 to 76%, the mean volumetric production was 1.7 L CH4 (L reactor d)-1 in the system, and the higher conversions were around at 0.20 L CH4 (g CODremoved)-1 in R1 and R2. The mean values of pH in the effluents ranged from 6.8 to 8.3 and the mean values of total volatile acids remained below 200 mg L-1 in the effluent of R3. The concentrations of total phenols of the affluent ranged from 45 to 278 mg L-1, and the mean removal efficiency was of 52%. The start-up of the anaerobic treatment system occurred after 30 days of operation as a result of inoculation with anaerobic sludge with active microbiota.

Removal of copper(II) from sugar-cane spirits employing chitosan

A method employing chitosan as complexant agent in the removal of copper(II) ions generally present in the Brazilian cachaça samples is herein proposed. The efficiency of this method is attributed to its high capacity of metal cations adsorption, mainly due to presence of hydroxyl and amine groups that can serve as chelating sites. The removal of copper(II) ions from this alcoholic beverage was efficient employing either in column and batch system. The analysis were carried out employing the flame atomic absorption spectrometry and the remaining copper(II) concentrations in the treated cachaça were lower than LOD of FAAS technique.

Biosorption and removal of chromium from water by using moringa seed cake (Moringa oleifera Lam.)

This study evaluated the adsorption capacity of chromium from contaminated aqueous solutions by using Moringa oleifera Lam. seeds. Parameters such as solution pH, adsorbent mass, contact time between solution and adsorbent, isotherms, thermodynamic, kinetics, and desorption were evaluated. The maximum adsorption capacity (Qm) calculated to be 3.191 mg g-1 for the biosorbent. Activated carbon was used for comparison purposes in addition to the biosorbent. The best fit was obtained by the Langmuir model for both adsorbents. The average desorption value indicated that both the biosorbent and activated carbon have a strong interaction with the metal. The results showed that the biosorbent has advantages owing to its low cost and efficiency in Cr3+ removal from contaminated waters.

Preparation and evaluation of magnetic chitosan particles modified with ethylenediamine and Fe(III) for the removal of Cr(VI) from aqueous solutions

The adsorption of Cr(VI) in aqueous solution by magnetic particles of crosslinked chitosan-ethylenediamine-Fe(III) (MPCh-EDA-FeCL) was studied in a batch system. Fe3+ in the MPCh-EDA-FeCL permitted that adsorption of Cr(VI) occurred with maximum efficiency between pH 3 and 11. The maximum adsorption capacity at pH 7.0 was 81.04 mg g-1 at 25 ºC. The adsorption kinetic process was described by the pseudo-second-order model. Thermodynamic parameters indicated spontaneous, exothermic and chemical adsorption nature. The adsorbent was successively regenerated using a 0.1 mol L-1 NaOH solution. Results were satisfactory for treatment of wastewater from the electroplating industry.

Evaluation of the effect of the seed extract of Moringa oleifera Lam over the efficiency of organic filters in wastewater treatment of dairy cattle breeding

This study aimed to evaluate the effect of Moringa oleifera Lam extract on the removal of total solids (TS), total suspended solids (TSS) and chemical oxygen demand (COD), in different filter media for treating wastewater of dairy cattle breeding (DCW). The moringa seed extract was obtained by grinding 50 g of seeds in one liter of distilled water and, after passing the solution through a quantitative paper filter of 25 microns, 60 mL of the extract were added to wastewater from cattle breeding before the filtration process in organic filters made of thin coal, bamboo leaves, eucalyptus leaves, gliricidia branches and sawdust. This was followed by the completely randomized experimental design, adopting a factorial of 5 x 2. Aliquots of filtered effluent were collected and the total solids (TS) concentrations, total suspended solids (TSS) and chemical oxygen demand (COD) were determined. It was found that the increase in the efficiency of removal of COD and total solids can be attributed to the coagulating power of the moringa seed extract, wherein the filter medium with bamboo leaves presented the best performance, showing potential for use as alternative filter material in the primary treatment of DCW.