Remediação de áreas contaminadas: uma avaliação crítica da legislação brasileira / Remediation of contaminated sites: a critical analysis of Brazilian legislation

RESUMO Este trabalho teve por objetivo analisar, de forma crítica, a legislação brasileira que regulamenta o tema das áreas contaminadas. A legislação paulista também foi avaliada pelo fato de o Estado de São Paulo ter sido o pioneiro no enfrentamento do problema. A metodologia utilizada nesta pesquisa foi a bibliográfica de cunho qualitativo, com utilização de doutrina nacional e internacional, bem como sítios da internet. Concluiu-se que é urgente que se chegue a um consenso nacional sobre o conceito de solo; que as legislações nacional e paulista, ao adotarem critérios e metodologias de investigação próprios de países desenvolvidos, deixam de conformar a realidade e as especificidades brasileiras; que é essencial a participação da comunidade envolvida em todas as etapas do processo de remediação; que a tomada de decisão não deve ser realizada apenas com base nos valores orientadores, mas na realização de análises detalhadas de risco ecológico e à saúde humana no local contaminado.

ABSTRACT This study aimed to critically examine the Brazilian legislation that regulates the theme of contaminated areas. The legislation of São Paulo State was also assessed because this state was the pioneer in facing the problem. This study's methodology involves a qualitative overview of the bibliography, using both international and national legal doctrine, as well as websites. It was concluded that a national consensus regarding the concept of soil is required; the Brazilian and São Paulo State legislations, by adopting rules and guidelines established in the developed countries, failed to disregard Brazilian reality and specificities; the participation of the community involved at all stages of the remediation process is essential; the decision-making should not be based solely on the generic quality soil standards, but also on the ecological and human health risk analyses at a specific contaminated site.

Phosphorus recovery from sewage with a sustainable and low-cost treatment system.

This study proposes a technology conceived based on an integrative approach that aims to promote phosphorus recovery and to recycle ferric water treatment sludge (FWTS), using it as a phosphorus adsorbent which may be applied as a soil ameliorant after reaching saturation. The assessed pilot plant operated with a daily influent flow of 360 litres and presented a removal efficiency of 94.4% ± 3.2% for chemical oxygen demand (COD) and of 91.2% ± 7.8% for suspended solids. It also presented promising results for phosphorus removal. The maximum efficiency of dissolved reactive phosphorus removal was 95% on the first day and it decreased until reaching adsorbent saturation. The estimated breakthrough time was one year in the condition in which the filling medium of a second constructed wetland was only FWTS. In this situation, the effluent phosphorus concentration was 0.2 mg·L-1. The authors concluded that the application of FWTS in a constructed wetland bed is an interesting alternative. Batch adsorption experiments were run using phosphorus stock solution. Langmuir and Freundlich adsorption isotherm models were obtained for different initial pH values. The maximum adsorption capacity decreased as the initial pH was increased; values ranged from 4.76 mg P·g-1 (pH = 3.9) to 1.44 mg P·g-1 (pH = 9.0).

Nucleação na formação de estruvita: estado da arte / Nucleation in the formation of struvite: state of art

RESUMO Estimativas recentes indicam que a duração de toda a reserva de rochas fosfatadas do planeta não ultrapassa 400 anos e que a produção de fertilizantes nitrogenados é insustentável energeticamente. Atualmente, o tratamento de esgoto está sendo visto como uma unidade de recuperação de recursos (água, energia e nutrientes) em vez de uma de final de tubo. Portanto, as tecnologias de recuperação devem ser priorizadas em relação às de remoção. Estruvita (fosfato de amônio e magnésio) é um cristal que pode ser produzido a partir do esgoto doméstico e tem maior eficiência agrícola do que os fertilizantes convencionais. Apesar de a cristalização ser um tema bastante estudado em todo o mundo e extremamente desenvolvido tecnologicamente, sua utilização na engenharia sanitária ainda não é comum, especialmente no Brasil. Um dos assuntos menos pesquisados na formação da estruvita é a nucleação. Portanto, o presente artigo traz uma revisão bibliográfica crítica e atual e mostra as lacunas no conhecimento sobre esse assunto.

ABSTRACT Recent estimation for the duration of global phosphate reserves does not exceed 400 years and the production of nitrogen fertilizers is energetically unsustainable. Nowadays, wastewater treatment plants have been seen as resource recovery facilities (water, energy and nutrients) instead of "end-of-pipe" utilities. Thus, nutrient-recovery technologies should be prioritized over the removal ones. Struvite (phosphate of ammonium and magnesium) is a crystal, produced from sewage, with a higher agricultural efficiency when compared to conventional fertilizers. Despite the crystallization is a topic extensively studied worldwide and highly technologically developed, its use in sanitary engineering is still not common, especially in Brazil. As the aspects related to struvite nucleation have been insufficiently studied, this paper presents a critical and updated literature review, and shows the gaps in the current knowledge about this topic.

Biomass growth and its mobility in an AnSBBR treating landfill leachate.

This work used a pilot scale (with a total volume of 1300 L) Anaerobic Sequencing Batch Biofilm Reactor (AnSBBR) to treat landfill leachate from São Carlos-SP (Brazil) as well as to evaluate the biomass growth and its behavior. Biomass from the bottom of a landfill leachate stabilization pond was immobilized in polyurethane foam cubes as inoculum. The leachate characteristics varied during the experiment. Ethanol or volatile fatty acids were added as additional substrate when the leachate was temporarily recalcitrant. After acclimation, the AnSBBR presented efficiency over 70% (COD removal). A mass balance model, biomass sampling and temporal concentration profiles were performed to obtain a biomass yield coefficient of YX/S = 0.0251 ±â€¯0.0006 gTVS gCOD removed (r2 = 0.999). Additionally, it was observed that a variable fraction of the attached biomass may detach itself or present mobility during the batch time, however returning to fixed bed depending on the substrate type and concentration. This behavior has never been reported by the literature for attached biomass.

Quantificação da produção de lodo de estações de tratamento de água de ciclo completo: uma análise crítica / Quantification of complete cycle water treatment plant sludge production: a critical assessment

RESUMO Grande parte do lodo gerado em estações de tratamento de água (ETAs) no Brasil ainda é disposta em rios ou em aterros sanitários. Contudo, principalmente em grandes centros urbanos, legislações ambientais restritivas e custos logísticos crescentes têm levantado interesse em usos benéficos para esse resíduo. Para uma avaliação dos possíveis usos, além do conhecimento das características qualitativas do lodo, operadores e projetistas de ETAs devem ser capazes de prever, com algum grau de confiabilidade, sua massa e volume. Os objetivos deste trabalho são: comparar o desempenho de dois dos principais métodos quantitativos de estimativa de produção de lodo - o método de fórmulas empíricas e o de balanço de massa; investigar a prática disseminada de se estimar a concentração de sólidos em suspensão totais na água bruta por meio de modelos de regressão linear com a turbidez como variável independente e delinear condições para a aplicação dessa correlação.

ABSTRACT Most of the water treatment plant (WTP) residuals generated in Brazil are still discharged into water bodies, or disposed in landfills. However, especially in large urban areas, ever-stringent environmental legislation and rising logistical costs have put focus into beneficial uses for those residuals. To evaluate the possible beneficial uses, beyond the knowledge of qualitative characteristics of the residuals, operators and designers should be able to predict, with some degree of certainty, its mass and volume. The objectives of this work are: to compare the performance of two of the main quantitative estimation methods for residuals production - the empirical formulas and the mass balance; to investigate the widespread practice of estimating the concentration of total suspended solids using turbidity as a surrogate; and to identify the conditions under which such procedure is acceptable.

First-order kinetics of landfill leachate treatment in a pilot-scale anaerobic sequence batch biofilm reactor.

This paper reports the kinetics evaluation of landfill leachate anaerobic treatment in a pilot-scale Anaerobic Sequence Batch Biofilm Reactor (AnSBBR). The experiment was carried out at room temperature (23.8 ± 2.1 °C) in the landfill area in São Carlos-SP, Brazil. Biomass from the bottom of a local landfill leachate stabilization pond was used as inoculum. After acclimated and utilizing leachate directly from the landfill, the AnSBBR presented efficiency over 70%, in terms of COD removal, with influent COD ranging from 4825 mg L(-1) to 12,330 mg L(-1). To evaluate the kinetics of landfill leachate treatment, temporal profiles of CODFilt. concentration were performed and a first-order kinetics model was adjusted for substrate consumption, obtaining an average k1 = 4.40 × 10(-5) L mgTVS(-1) d(-1), corrected to 25 °C. Considering the temperature variations, a temperature-activity coefficient θ = 1.07 was obtained. Statistical "Randomness" and "F" tests were used to successfully validate the model considered. Thus, the results demonstrate that the first-order kinetic model is adequate to model the anaerobic treatment of the landfill leachate in the AnSBBR.

Aplicação de processos físico-químicos como alternativa de pré e pós-tratamento de lixiviados de aterros sanitários / Physical-chemical processes as an alternative to pre-and post-treatment of landfill leachate

O presente artigo objetivou avaliar a aplicação da operação de stripping como pré-tratamento de um lixiviado de aterro sanitário visando à redução da carga de amônia afluente a um sistema biológico de tratamento, bem como, a utilização do processo de coagulação-floculação-sedimentação para a remoção da matéria orgânica recalcitrante de um lixiviado de aterro pré-tratado em um sistema de lodo ativado. As taxas de remoção de nitrogênio amoniacal variaram entre 3,5 e 3,6 mg N-NH3.L-1.h-1 para o sistema de stripping composto por um reator submetido à agitação mecânica e entre 3,2 e 3,3 mg N-NH3.L-1.h-1 para o reator submetido à aeração com bolhas grossas. Quanto ao pós-tratamento, os resultados obtidos indicaram que são requeridas dosagens acima de 400 mg Fe+3.L-1 e 400 mg Al+3.L-1, para a obtenção de eficiências de remoção de matéria orgânica recalcitrante superiores a 90 por cento.

The aim of this article was evaluate the implementation of the ammonia stripping as a pretreatment for landfill leachate and the use of the coagulation-flocculation-sedimentation process for the removal of refractory organic compounds present in a landfill leachate pretreated in an activated sludge system. The rates of ammonia nitrogen removal ranged between 3.5 and 3.6 mg NH3-N.L-1.h-1in a lab scale reactor (working volume of 20 L) equipped with a mechanical stirrer and 3.2 and 3.3 mg NH3-N.L-1.h-1in a lab scale aerated column (working volume of 10 L). It was possible to achieve removals above 90 percent of refractory organic compounds (measured as apparent color) applied coagulant dosage about 400 mg Fe+3.L-1 and 400 mg Al+3.L-1.

Biodegradation of di(2-ethylhexyl)phthalate in a typical tropical soil.

The aim of this research was to evaluate the possibility of biodegradation of di(2-ethylhexyl)phthalate (DEHP), widely used as an industrial plasticizer and considered an endocrine-disrupting chemical included in the U.S. Environmental Protection Agency priority list, in a Brazilian tropical soil, which has not been previously reported in the literature, despite the geographic importance of tropical soils. Preliminary laboratory testing comprised respirometric, air and water permeability, and pilot scale infiltration tests. Standard respirometric tests were found inadequate for studying biodegradation in tropical contaminated soils, due to the effect of the addition of significant amounts of calcium carbonate, necessary to adjust soil pH. Pilot scale infiltration tests performed for 5 months indicated that DEHP was retained in the superficial layer of the soil, barely migrating downwards, whereas air and water permeability tests discarded in situ bioremediation. However, ex situ bioremediation was possible, using a slurry-phase reactor with acclimated microorganisms, in pilot scale tests conducted to remediate a total mass of 150 kg of contaminated soil with 100 mg DEHP/kg. The removal of DEHP in the slurry-phase reactor achieved the percentage of 99% in 49 days, with biodegradation following a first-order kinetic model with a biodegradation coefficient of 0.127 day(-1).

Tratabilidade de solos tropicais contaminados por resíduos da indústria de revestimentos cerâmicos / Treatability of tropical soils contaminated by solid wastes from ceramic tile industry

Este trabalho de pesquisa buscou investigar a eficácia da remoção de chumbo (Pb) e zinco (Zn) de uma área contaminada pelo depósito inadequado de resíduos de indústrias de revestimentos cerâmicos do pólo de Santa Gertrudes (São Paulo, Brasil), ocorrido há cerca de trinta anos atrás. Foram avaliados três processos de lixiviação: lavagem com ácido sulfúrico concentrado e por soluções de peróxido de hidrogênio a 30 por cento e de ácido clorídrico 0,1 M. Os resultados obtidos mostraram que o tratamento com peróxido de hidrogênio não removeu Pb e Zn; que a lavagem com ácido sulfúrico concentrado promoveu a redução de 50 por cento dos teores de Zn e a solução de ácido clorídrico 0,1 M reduziu os teores de Pb e Zn em 15 por cento e 10 por cento, respectivamente. O teor remanescente de Zn no solo tratado com ácido sulfúrico concentrado foi de 117 mg/kg e os de Pb e Zn no solo lavado com a solução de ácido clorídrico 0,1 M, de 806 mg/kg e 213 mg/kg, respectivamente, valores estes inferiores aos de intervenção estabelecidos pelo órgão de controle ambiental paulista.

The aim of this research was to evaluate different leaching processes to the removal of lead (Pb) and zinc (Zn) from tropical soil contaminated by inappropriate past deposition of wastes from ceramic tile industries of Santa Gertrudes (São Paulo, Brazil). Three soil washing processes were investigated: with concentrated sulphuric acid, with a 30 percent solution of hydrogen peroxide and with 0.1M solution of hydrochloric acid. The results indicated that the treatment with hydrogen peroxide did not remove Pb and Zn significantly; the washing with concentrated sulphuric acid caused a 50 percent reduction of Zn contents and the 0.1M solution of hydrochloric acid reduced Pb and Zn contents in 15 percent and 10 percent, respectively. The Zn content remaining in the soil processed with concentrated sulphuric acid was 117 mg/kg and the Pb and Zn contents remaining in the soil processed with 0.1M solution of hydrochloric acid were 806 mgPb/kg and 213 mgZn/kg, respectively, values which are lower than intervention ones established by São Paulo State environmental protection agency.

Avaliação da eficácia dos critérios de recebimento de efluentes não domésticos em sistemas de coleta e transporte de esgotos sanitários em São Paulo / Effectiveness of acceptance standards of non-household effluents to São Paulo state publicly owned treatment works

No presente trabalho, foram correlacionadas características de efluentes não domésticos, lançados no sistema de esgotos sanitários da Região Metropolitana de São Paulo (SES-RMSP), com os dados de manutenção. Foram também realizadas medições do limite inferior de explosividade e de concentrações de sulfetos nos principais coletores-tronco e interceptores deste sistema. Dos resultados obtidos, concluiu-se que: os critérios atuais de recebimento de efluentes não domésticos no SES-RMSP, no que se refere às interferências físicas e operacionais, não são eficazes; para a análise da possiblidade de recebimento, devem ser levados em consideração as matérias-primas, produtos auxiliares e fluxogramas do processo produtivo; deve haver comunicação entre as diversas áreas envolvidas na operação do SES-RMSP e a concessionária deve fazer o monitoramento sistemático do limite inferior de explosividade.

In this research work, some characteristics of non-household effluents which are conveyed into the sanitary sewerage system of São Paulo's Metropolitan Region (SPMR's Sewerage System) were correlated to maintenance data. Measurements of inferior limit of explosion and sulfide concentrations in the sewage mains and interceptor lines were also conducted. The results led us to conclude that the current non-domestic effluent collection criteria in SPMR's Severage System are not effective with regard to physical and operational interferences. Auxiliary products, raw materials and the production process flux itself must be taken into consideration in the analysis made to evaluate whether or not such effluents can be conveyed into the Severage System. There must be communication among the sectors involved in the operation of SPMR's Sewerage System and the responsible Sewerage Company in charge should monitor the inferior limit of explosion at all times.

Viabilidade da aplicação do método respirométrico de Bartha para determinação da biodegradação de poluentes ou resíduos em latossolos / Feasibility of application of Bartha's respirometric method to determine biodegradation of pollutants or wastes in latosoils

Para avaliar a possibilidade de biorremediação em áreas contaminadas, é necessário determinar a biodegradação dos poluentes no solo. Para esta determinação, emprega-se comumente no Brasil, o método respirométrico de Bartha, adaptado de uma norma holandesa. Porém, os solos tropicais possuem características bem diferentes dos solos de regiões de clima temperado. Neste trabalho, foi estudada a aplicabilidade de tal método para um latossolo, tipo de solo predominante no Estado de São Paulo. A partir dos resultados obtidos, foi possível verificar que reações abióticas geram gás carbônico em quantidades significativas. Constatou-se, também, a dificuldade de esterilização do solo em autoclave, o que impossibilita a avaliação da remoção dos poluentes por outros mecanismos ou a biodegradação dos mesmos por microrganismos exógenos somente. Portanto, não se recomenda a aplicação do teste respirométrico de Bartha para a determinação da biodegradabilidade de poluentes em latossolos.

One of the major parameters that influence the feasibility of using bioremediation in contaminated sites is the biodegradability of the compounds of concern. The Bartha's respirometric method, adapted from a Dutch norm, is a common method used in Brazil to determine such biodegradability. However, tropical soils present different characteristics as compared to soils from regions of temperate climate. In this research, its applicability was studied for a latosoil, which is the predominant soil type in São Paulo State, Brazil. Based on the results of this study, it can be concluded that abiotic reactions in latosoil generated carbonic gas in significant concentrations. Furthermore, this research verified the difficulty of sterilizing the soil, which would make it difficult to evaluate the removal of contaminants by other mechanisms or the biodegradation by exogenous microorganisms. Therefore, the application of BarthaÆs respirometric method is not recommended to determine the biodegradability of pollutants in latosoils.