Juacyara Carbonelli Campos

Heterogeneous fenton process using the mineral hematite for the discolouration of a reactive dye solution

This work reports a study on the heterogeneous Fenton reaction using hematite powder (Fe2O3) in suspension for the discolouration of the reactive dye Drimarene Red X-6BN in aqueous solutions. The efficiency of the process was studied as a function of the experimental conditions: initial pH; H2O2 dose; and hematite powder concentration; all of which showed a strong effect on the reaction kinetics. Under the best experimental conditions: pH = 2.5; H2O2 dose = 800 mg/L; and [Hematite] = 20 g/L, it was possible to remove about 99% of the initial colour in 120 minutes in a batch reaction at 25oC. The analysis of the kinetic results suggests that the reaction is initiated by heterogeneous generation of free radicals on the hematite surface, but as soluble iron (III) and iron (II) species are released into the solution during the course of the reaction, a simultaneous homogeneous Fenton reaction step propagates and contributes to the overall reaction.

Evaluation of pH, alkalinity and temperature during air stripping process for ammonia removal from landfill leachate

The objective of this research was to evaluate the air stripping technology for the removal of ammonia from landfill leachates. In this process, pH, temperature, airflow rate and operation time were investigated. Furthermore, the relationship between the leachate alkalinity and the ammonia removal efficiency during the process was studied. The leachate used in the tests was generated in the Gramacho Municipal Solid Waste Landfill (Rio de Janeiro State, Brazil). The best results were obtained with a temperature of 60oC, and they were independent of the pH value for 7 h of operation (the ammonia nitrogen removal was greater than 95%). A strong influence of the leachate alkalinity on the ammonia nitrogen removal was observed; as the alkalinity decreased, the ammonia concentration also decreased because of prior CO2 removal, which increased the pH and consequently favored the NH3 stripping. The air flow rate, in the values evaluated (73, 96 and 120 L air.h−1. L−1 of leachate), did not influence the results.

Removal of COD from a stabilized landfill leachate by physicochemical and advanced oxidative process.

This work investigated the effectiveness of a physicochemical and oxidative process for the removal of chemical oxygen demand (COD) from stabilized landfill leachates. The application of these technologies for landfill leachate treatment greatly depends on the optimal operating conditions for a specific leachate. Coagulation-flocculation followed by H2O2, Fenton and photo-Fenton processes was evaluated. Advanced oxidation processes were evaluated in the raw leachate and the leachate pretreated by coagulation-flocculation. Via the coagulation process, at 30 sec and a stirring speed of 150 rpm followed by flocculation and settling steps, 53% COD was removed at an optimal dose of 1400 mg L−1 and pH 4.0. Moreover, from the POA evaluated, the Fenton process was determined to be the most effective process for removing COD from the leachate pretreated by coagulation-flocculation, reaching 83.3% COD removal with 1330 mg L−1 of H2O2 and 266 mg L−1 of Fe2+. The photo-Fenton process applied directly to the raw effluent was effective for the removal of COD; a 75% reduction in COD was observed in tests using 2720 mg L−1 of H2O2 and 544 mg L−1 of Fe2+. Due to the variability in the composition of the Gramacho landfill leachate, the combination of coagulation-flocculation and the Fenton process is an effective technology for reducing the COD in samples of this leachate.

Caracterização microbiológica de lixiviados gerados por resíduos sólidos domiciliares e de serviços de saúde da cidade do Rio de Janeiro

The present paper consisted on the microbiological characterization of leachate generated from solid waste from health services and municipal solid waste. This study aimed to support the discussion about the need for differentiated treatment and disposal for the health services solid waste. The following parameters were selected: total coliforms, thermotolerant coliforms, Escherichia coli, Enterococci, trials for Pseudomonas aeruginosa, and Salmonella and other Enterobacteria, analysis of susceptibility to antimicrobials and research on antimicrobial activity of the leachate. Expressive densities were observed in microbial populations in health services and municipal solid waste, with values ranging from 108 to 109. In both wastes, resistant and susceptible strains to antimicrobials occurred and none were resistant to all antibiotics tested. Results showed similarities for both types of waste and reinforce the recommendation for health services and municipal solid waste co-disposal in sanitary landfills.

Wetlands para tratamento de lixiviados de aterros sanitários: experiências no aterro sanitário de Piraí e no aterro metropolitano de Gramacho (RJ)

ABSTRACT The Group of Solid Waste of Environmental Engineering Program (PEAMB/UERJ) has been conducting research using constructed wetlands in landfi ll leachate treatment in the last fi ve years. These systems promote the absorption of nutrients by the vegetation and facilitate the degradation of organic material by microorganisms in the soil and the ones adhered to the roots. Experiments carried out in Pirai Municipality Landfi ll show removal of pollutants about 41% of COD and 51% of ammonium nitrogen. The results obtained in Gramacho’s landfi ll, present a reduction of 86% of COD load and 89% of ammonium nitrogen load. Wetlands seens to be a good alternative in the treatment of landfi ll leachate, especially in regions of tropical climate, where high temperatures improve effects of evapotranspiration. KEYWORDS: Constructed wetlands , leachate treatment, evapotranspiration, Gramachos’ metropolitan landfi ll, Pirai’s Landfi ll. C AMILLE F ERREIRA M ANNARINO Mestre em Engenharia Ambiental - PEAMB/UERJ. Engenheira Civil - Enfase em Engenharia Sanitaria e Ambiental – FEN/UERJ. Bolsista CNPq/ PROSAB

Removal of boron from oilfield wastewater via adsorption with synthetic layered double hydroxides.

Hydrotalcite is a layered double hydroxide (LDH) consisting of brucite‐like sheets of metal ions (Mg‐Al). In this work, hydrotalcites were synthesized, and boron removal from oilfield wastewater was evaluated. LDHs were synthesized using the co‐precipitation method. The calcined products (CLDHs) were obtained by heating at 500°C and characterized using X‐ray diffraction, X‐ray fluorescence, thermogravimetric analysis and the specific surface area (BET). The affinity of LDHs for borate ions was evaluated for calcined and uncalcined LDHs as a function of contact time, initial pH of the oilfield wastewater (pH ∼ 9) and the LDH surface area. The tests were conducted at room temperature (approximately 25ºC). The results indicated that 10 min were needed to reach a state of equilibrium during boron removal for calcined LDHs due to the high surface area (202.3 m2 g−1) regardless of the initial pH of the oilfield wastewater, which resulted from the high buffering capacity of the LDHs. The adsorption capacity increased as the adsorbents levels increased for the range studied. After treatment of the oilfield wastewater containing 30 mg L−1 of boron with Mg‐Al‐CO3‐LDHs, the final concentration of boron was within the discharge limit set by current Brazilian environmental legislation, which is 5 mg L−1. Pseudo–first‐order and pseudo–second‐order kinetic models were tested, and the latter was found to fit the experimental data better. Isotherms for boron adsorption by CLDHs were well described using the Langmuir and Freundlich equations.

Municipal solid waste in Brazil: A review:

The production of municipal solid waste (MSW) represents one of the greatest challenges currently faced by waste managers all around the world. In Brazil, the situation with regard to solid waste management is still deficient in many aspects. In 2015, only 58.7% of the MSW collected in Brazilian cities received appropriate final disposal. It was only as late as 2010 that Brazil established the National Policy on Solid Waste (NPSW) based on the legislation and programmes established in the 1970s in more developed countries. However, the situation with regard to MSW management has changed little since the implementation of the NPSW. Recent data show that, in Brazil, disposal in sanitary landfills is practically the only management approach to MSW. Contrary to expectations, despite the economic recession in 2015 the total annual amount of MSW generated nationwide increased by 1.7%, while in the same period the Brazilian population grew by 0.8% and economic activity decreased by 3.8%. The article describes the panorama with regard to MSW in Brazil from generation to final disposal and discusses the issues related to the delay in implementing the NPSW. The collection of recyclable material, the recycling process, the application of reverse logistics and the determination of the gravimetric composition of MSW in Brazil are also addressed in this article. Finally, a brief comparison is made between MSW management in Brazil and in other countries, the barriers to developing effective waste disposal systems are discussed and some recommendations for future MSW management development in Brazil are given.

Sequential treatment of an old-landfill leachate

This work investigates the performance of combined techniques applied to the treatment of an old-landfill leachate, which presents high salinity, low biodegradability (BOD5/COD around 0.05) and high ammonia concentration. Three sequences of processes were employed, including coagulation/flocculation, chemical oxidation, biological treatment and ammonia stripping. The association of coagulation/flocculation with ozonation promoted an increase on landfill leachate biodegradability (BOD5/COD raised to 0.20). Ammonia stripping was an essential procedure for reducing toxic effects on the biological treatment step. The treatment sequence combining coagulation/flocculation, ammonia stripping, ozonation and biological treatment led to high global removals of COD (92%) and DOC (95%).

Evaluation of the biodegradability and toxicity of landfill leachates after pretreatment using advanced oxidative processes

Leachate from urban solid waste landfills is a complex mixture of organic and inorganic substances that cause damage to the environment, due to the high concentration of recalcitrant organic matter and toxicity. The objective of this study was to apply advanced oxidation processes (AOP), namely the dark Fenton and solar photo-Fenton processes, to young and old landfill leachates prior to biological treatment. The leachates were obtained from the Seropedica and Gramacho landfill sites, respectively, located in Rio de Janeiro State, Brazil. For the two Fenton processes, different conditions of pH (1.5, 3.0 and 5.0) and Fe2+: H2O2 ratio (1:2, 1:5 and 1:10) were evaluated. Biodegradability was evaluated using the Zahn-Wellens methodology and Aliivibrio fischeri acute toxicity tests were conducted in order to predict the toxicity in the activated sludge. The best conditions for both Fenton processes were pH of 3.0 and Fe2+: H2O2 and CODRAW:H2O2 mass ratios of 1:5 and 1:1, respectively. The solar photo-Fenton process was more effective at improving the quality for both leachates, reaching COD, TOC and abs 254 nm reductions of 82%, 85% and 96.3%, respectively, for the Seropedica landfill leachate. In the case of the Gramacho landfill leachate, the corresponding reductions were 78.2, 80.7% and 91.1%, respectively. The biodegradability results for the untreated leachates from the Seropedica and Gramacho sites were 65% and 30% respectively. The biodegradability of both leachates was improved by the Fenton processes, especially the solar photo-Fenton process, which increased the leachate biodegradability to 89% (Seropedica) and 69% (Gramacho). For both leachates, a greater reduction in the acute toxicity was achieved with the solar photo-Fenton compared to the dark-Fenton process. The Seropedica landfill leachate showed high toxicity (EC50 = 33%, 15 min), after the dark Fenton and solar photo Fenton processes, with EC50 values of 81 and 91%, respectively. In the case of Gramacho landfill leachate toxicity, the EC50 value of the raw leachate was 13%, whereas after the dark Fenton and solar photo Fenton processes the corresponding values were 54% and 59%, respectively. These results indicate that the Fenton process (especially solar photo-Fenton), was efficient in terms of increasing the biodegradability and reducing the toxicity of the leachate. This is important in relation to protecting the microbiological community in the activated sludge process.

Oilfield Produced Water Treatment by Ceramic Membranes: Mass Transfer and Process Efficiency Analysis of Model Solutions

This work evaluated the performance of ceramic membranes in removing dispersed oil present in oilfield produced water, seeking to advance knowledge of the process, and identify the conditions for its application. The effect of the operating conditions and effluent characteristics were evaluated across a wide range, enabling establishment of operational limits for the permeation process. It was demonstrated that a flow regime corresponding to a Reynolds number (Re) greater than 6,000 does not imply significant improvements in membrane permeability. It was further found that the permeate flux exhibits a slight linear dependence with the salt concentration (CS).