Wagner Guadagnin Moravia

Evaluation of landfill leachate treatment by advanced oxidative process by Fenton's reagent combined with membrane separation system.

A high content of refractory organic matter, ammonia and toxic compounds is characteristic of landfill leachate. Advanced oxidative processes (AOPs) are an attractive alternative for landfill leachate treatment. However, when applied as a unique process treatment, they do not provide a complete solution for the effluent treatment. Combining AOP with a membrane separation process (MSP) presents a number of benefits and provides an adequate solution for this problem. With this in mind, the present work aims to evaluate, using a bench scale, leachate treatability through AOP by Fentons reagent (AOP/Fenton) combined with microfiltration (MF) and nanofiltration (NF). A high efficient removal of COD (63%), true color (76%) and humic substances (50%) was observed during AOP/Fenton under optimized conditions (1.7 g H(2)O(2)/g COD(raw)(leachate); FeSO(4) · 7H(2)O:H(2)O(2)=1:5.3; pH=3.8; reaction conditions = 115 rpm/28 min). According to the evaluated parameters, MSP presented an efficient complementary treatment, in which the integrity of the stages was sufficient for reaching regulatory levels in the effluent (Deliberação Normativa Conjunta COPAM/CERH-MG N(o). 1, May 5, 2008).

Nanofiltration as post-treatment of MBR treating landfill leachate

AbstractLandfill leachate management has been a major environmental, economic, and social concern, and its treatment brings forth a challenge, especially regarding the high concentration of refractory organic matter, ammonia, and toxic compounds, which may vary considerably depending on the maturity, age, and biochemical reactions occurring in the landfill, besides the high variation on the volume generated. This study was aimed to investigate NF use as a post-treatment of landfill leachate that has been treated by membrane bioreactor (MBR). The experimental setup consisted of pilot plant comprised by an air stripping reactor, plus MBR and NF membranes. The pilot plant has a treatment capacity of 3 m3/d. The system has shown excellent leachate treatment performance, especially regarding the removal of chemical oxigen demand (80–96%), ammonia (85–95%), color (98–99.9%), and phosphorus (78–99.8%). The results have also shown the importance of NF to improve the effluent condition, and to produce treated effl...

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 Fentons reagent (AOP/Fenton). In this context, the aim of this paper was to evaluate, in a bench scale, the treatability of leachate pos-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).

Pilot aerobic membrane bioreactor and nanofiltration for municipal landfill leachate treatment

ABSTRACT The purpose of this article is to evaluate the integration of the air stripping, membrane bioreactor (MBR) and nanofiltration (NF) processes for the treatment of landfill leachate (LFL). Pretreatment by air stripping, without adjustment of pH, removed 65% of N-NH3 present in LFL. After pretreatment, the effluent was treated in MBR obtaining 44% of COD removal, and part of the N-NH3 was converted to nitrite and nitrate, which was later removed in the post-treatment. Nanofiltration was shown to be an effective process to improve the removal of organic compounds, the high toxicity present in LFL and nitrite and nitrate generated in the MBR. The system (air stripping + MBR + nanofiltration) obtained great efficiency of removal in most parameters analyzed, with overall removal of COD, ammonia, color and toxicity approximately 88, 95, 100 and 100%, respectively. By this route, treated landfill leachate may be reused at the landfill as water for dust arrestment and also as earth work on construction sites.

Avaliação da microfiltração para remoção do lodo gerado no processo oxidativo avançado empregando o reagente de Fenton no tratamento de lixiviado de aterro sanitário

Advanced oxidation processes using Fentons reagent (AOP/Fenton) are an attractive alternative for landfill leachate treatment. However, the implementation of the AOP/Fenton is limited by the generation of sludge in the process. The sludge has a high iron concentration, which needs its separation from the treated effluent. The aim of this study was to evaluate the microfiltration for sludge removal from an AOP/Fenton. The work was conducted in bench scale. The advanced oxidation process showed high efficiency in removing organic matter (75%) and true color (95%). The microfiltration was effective in separating the sludge, which showed low settling hindering their separation by sedimentation, and has contributed to the removal of other pollutants.

Comparison of commercial baker’s yeast versus bacteria-based membrane bioreactors for landfill leachate treatment

ABSTRACT This study compares the performance of the membrane bioreactor (MBR) inoculated with commercial baker’s yeast (Saccharomyces cerevisiae) (MBRy) versus one inoculated with bacterial sludge (MBRb) for treatment of landfill leachate. The MBRb and MBRy were operated with a hydraulic retention time of 48 h, solids retention time of 60 d, and specific air demand based on membrane area of 0.6 m3 h−1 m−2. The MBRy was more efficient in removing chemical oxygen demand (COD) (68 ± 12%), color (79 ± 8%), ammoniacal nitrogen (58 ± 18%), and phosphorus (62 ± 19%) compared to MBRb, which showed removal efficiencies of 44 ± 18%, 46 ± 20%, 45 ± 17%, and 29 ± 15% for COD, color, ammoniacal nitrogen, and phosphorus. Furthermore, the MBRy had lower production of soluble microbial products, which are the main cause of membrane fouling, and so a lower membrane fouling potential. The average hydraulic permeability of the MBRy (32.23 L m−2 h−1 bar−1) was about four times higher than that of the MBRb (8.34 L m−2 h−1 bar−1). Thus using commercial baker’s yeasts as a MBR inoculum can enhance pollutants’ removal and membrane performance.

Characterization of residual organic compounds of aerobic degradation of landfill leachate

ABSTRACT The purpose of this article is to characterize and compare the residual COD of raw landfill leachate and its low and high molecular weight fractions before and after aerobic degradation process. The low and high molecular weight fractions (<10 kDa and >10 kDa, respectively) were obtained by the use of an ultrafiltration cell. Samples of the fractions with molecular weights 10 kDa, as well as the raw leachate, were characterized in terms of COD, protein, carbohydrate and lipid concentration and by biodegradability test. The compound identification of all samples was carried out using gas chromatography coupled with mass spectrometry (GC/MS). The results show that the landfill leachate studied is constituted of approximately 60% of compounds with molecular weight <10 kDa. Approximately 80% of the compounds identified in the leachate had been degraded. This is an indication that most of the compounds that constitute the significant fraction of residual COD correspond to intermediate products and products of condensation of affluent compounds or had been generated during the degradation (SMP). Similar compounds were identified in all effluents of the degradation assay, suggesting the presence of SMP. These compounds, predominantly aliphatic and esters, are characterized by high molecular weight and probable refractory nature.

Long-term use of the critical flux for fouling control in membrane bioreactors treating different industrial effluents: bench and pilot scale

AbstractThis paper presents an evaluation, in the long term, of the critical flux test as a tool to monitor and control fouling in membrane bioreactors (MBRs). The critical flux was assessed in this work on bench- and pilot-scale MBRs treating different kinds of effluents. The results showed that the critical flux test is important for the indication of the optimal operational flux and serves as a tool to compare propensity to fouling in several systems, independent of the characteristics of the feed or the operational conditions. The results also show that the improvement in the quality of the sludge or the improvement in the hydrodynamic conditions is an effective example of alternatives to increase the critical flux. As an example, these improvements can be achieved by dosing powder activated carbon, improving specific membrane permeability or increasing aeration rate.

Hybrid MF and membrane bioreactor process applied towards water and indigo reuse from denim textile wastewater

ABSTRACT This work investigates the application of a microfiltration (MF)–membrane bioreactor (MBR) hybrid process for textile dyeing process wastewater reclamation. The indigo blue dye was efficiently retained by the MF membrane (100%), which allows its recovery from the concentrate stream. MF promotes 100% of colour removal, and reduces the chemical oxygen demand (COD) and conductivity by about 65% and 25%, respectively, and improves the wastewater biodegradability. MF flux decline was mostly attributed to concentration polarization and the chemical cleaning was efficient enough to recover initial hydraulic resistance. The MBR provides to be a stable process maintaining its COD and ammonia removal efficiency (73% and 100%, respectively) mostly constant throughout and producing a permeate that meets the reuse criteria for some industry activities, such as washing-off and equipment washdown. The use of an MF or ultrafiltration (UF) membrane in the MBR does not impact the MBR performance in terms of COD removal. Although the membrane of MBR–UF shows permeability lower than MBR–MF membrane, the UF membrane contributes to a more stable operation in terms of permeability.

Coupling of nanofiltration with microfiltration and membrane bioreactor for textile effluent reclamation

ABSTRACT This work investigates the application of a microfiltration–membrane bioreactor–nanofiltration hybrid process for textile effluent reclamation. The indigo blue dye was efficiently retained by the microfiltration membrane (100%), which allows its recovery from the concentrate stream. The membrane bioreactor resulted in chemical oxygen demand (COD) and ammonia removal of 73% and 100%, respectively. Nanofiltration technology was successfully applied to polish textile effluent. The principal cause of flux decline was determined to be concentration polarization. The nanofiltration permeate meets the quality requirements for all processes within the textile industry, while the nanofiltration concentrate can be used for less demanding purposes.