Míriam Cristina Santos Amaral

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).

Two-stage anaerobic membrane bioreactor for the treatment of sugarcane vinasse: assessment on biological activity and filtration performance.

A two-stage submerged anaerobic membrane bioreactor (2-SAnMBR) was designed for the treatment of sugarcane vinasse. For start-up, the flow rate was reduced whenever VFA levels reached critical levels in the methanogenic reactor. After acclimation, the system was operated under a continuous flow. Separation of the stages was observed during the entire period of operation. VFA, COD and DOC levels of raw effluent, acidified effluent and permeate averaged 2141, 3525 and 61 mg VFA L(-1) (as acetic acid), 15727, 11512 and 488 mg COD L(-1), and, 3544, 3533 and 178 mg DOC L(-1), respectively. Overall COD and DOC removal efficiencies of 96.9±0.7% and 95.0±1.1%, respectively, were reached. Methane content of the biogas from the acidogenic and methanogenic reactors ranged 0.1-4.6% and 60.1-70.1%, respectively. Removable fouling strongly affected filtration performance and cake layer formation accounted for most of filtration resistance. Membrane resistance was related to presence of protein-like substances and carbohydrates.

TRATAMENTO DE LIXIVIADO DE ATERRO SANITÁRIO POR PROCESSO OXIDATIVO AVANÇADO EMPREGANDO REAGENTE DE FENTON

The objective of this work is to investigate the feasibility of fenton oxidation during the treatment of sanitary landfill leachate. A set of experiments were prepared at the Sanitary Landfill of Belo Horizonte - MG, where the process was conducted in a mixture reactor with 1000 L capacity. The results have shown a high effective removal of organic pollutants, where results for COD removal were above 46%, with an average of 61%, and the best removal rate around 75%. The use of Fenton oxidation has been proved to be a successful technique to be used as a preliminary treatment, clearly showing the possibility to be used in a real scale.

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...

Internal versus external submerged membrane bioreactor configurations for dairy wastewater treatment

AbstractTwo submerged membrane bioreactor (SMBR) configurations, one with the membrane module internal (SMBRi) and the other one external (SMBRe) to the biological tank, were used for the treatment of dairy industry effluent and evaluated in terms of pollutant removal capacity and fouling, focusing on the production of soluble microbial products (SMP) and extracellular polymeric substances (EPS). Both the MBRs presented excellent chemical oxygen demand (COD) removal efficiency (98% average), color (98%), and nutrients (86% for total nitrogen and 86–89% for total phosphorus); however, it was shown that shearing caused by the sludge recirculation pumps in the SMBRe reduced biomass growth considerably. The SMBRe presented better performance in terms of fouling than the SMBRi, which was associated with the higher concentration of suspended solids and SMP and EPS in the SMBRi. The SMP concentrations (mgSMP/gMLVSS) were superior in the SMBRe, showing that the friction from recirculation pumps leads to the break...

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).

Avaliação da biodegradabilidade anaeróbia de lixiviados de aterro sanitários

The objectives of this article were to investigate the favorable environment and operational conditions to the development of the anaerobic biodegradability test for landfill leachate. The evaluated conditions were the relation food/microrganismo (A/M), seed acclimatization, and toxicity due to high ammonia concentration. The results indicated that A/M relation equivalent to 0,45 was presented as most favorable to the accomplishment of the test, and that the seed used presented good capacity of adaptation to the leachate, not demanding previous acclimatization. The leachate in question presented relatively low anaerobic biodegradability, and associated to the results of previous studies of aerobic biodegradability suggest that a significant fraction of organic substance is refractory to the aerobic and anaerobic metabolism, indicating that the physical-chemical treatment must be used as form of pre or post-treatment.

Extending the life-cycle of reverse osmosis membranes: A review:

The reverse osmosis (RO) technology for desalination and demineralization serves the global water crisis context, both technically and economically, and its market is growing. However, RO membranes have a limited life-cycle and are often disposed of in landfills. The impacts caused by the disposal of thousands of tonnes per annum of RO membranes have grown dramatically around the world. Waste prevention should have a high priority and take effect before the end-of-life phase of a product is reached. In this review, a summary is presented of the main advances in the performance of the RO technology and the membrane lifespan. Afterwards, this paper reviews the most important relevant literature and summarizes the key findings of the research on reusing and recycling the discarded modules for the purpose of extending the life-cycle of the RO membranes. In addtion, there are some recent researches that indicated recycling RO membranes for use by the microfiltration or ultrafiltration separation processes is a promising solution to the disposal problem. However, there are many gaps and differences in procedures and results. This article also discusses and brings to light key parameters involved and controversies about oxidative treatment of discarded RO membranes.

Treatment of landfill leachate by hybrid precipitation/microfiltration/nanofiltration process

This paper describes a promising method to treat stabilized landfill leachate. Such method consists of a combination of chemical precipitation processes, a cost-effective technique with high potential to remove contaminants with foulant nature, microfiltration aimed at removing the produced precipitate and nanofiltration (NF) for final polishing. This study was carried out on a bench unit comprising a precipitation reactor associated with a submerged hollow-fiber microfiltration membrane module and a flat NF membrane cell operated in batch and continuous mode with a treating capacity of 0.1 L h(-1). Combining these processes yielded a clear and colorless permeate and proved to be very efficient at removing organic and inorganic matter. The results showed the importance of membrane processes to ensure treated landfill leachate quality. Also the precipitation associated with microfiltration as a pretreatment process is able to guarantee low membrane fouling due to the significant retention of humic substances which are known for their high potential to cause NF membrane fouling.

Characterization of landfill leachates by molecular size distribution, biodegradability, and inert chemical oxygen demand.

This work presents results from a detailed characterization of landfill leachates of different ages from a landfill in a major Brazilian city. This characterization consists of determining the molecular size distribution and the inert chemical oxygen demand (COD) and the biodegradability of both aerobic and anaerobic processes. Results show that leachate with a high COD concentration leachate has low biodegradability. A significant fraction of the COD is not characterized as protein, carbohydrate, or lipids, which reinforces the hypothesis that the remaining fraction was present in all leachate fractions (less than 1 kDa; between 1 and 10 kDa; between 10 and 100 kDa; and greater than 100 kDa) and is refractory. These results suggest that leachates with such characteristics require treatment systems that use physical-chemical processes as a pre- or post-treatment step to biological processes.