A stormwater user fee model for operations and maintenance in small cities.

In this paper, a stormwater fee specifically for small municipalities was developed through a simplification of the Equivalent Residential Unit (ERU) system, which is the main method applied in the United States. The Simplified ERU is based on the amount of impervious area and the fee considers the operations and maintenance costs, besides having a single class of billing. It was applied in Santo Amaro da Imperatriz city, located in the southern region of Brazil, which can be classified as a small city. The value of the Simplified ERU (294.32 m2) was similar to the average impervious area in the United States (269.42 m2) and it was equivalent to $0.28 per square meter (within the range of other countries' fees). The method proved to be a feasible and rapid technique for funding stormwater services, and its simplicity allows its application in different locations. This funding model can generate revenue to address current stormwater problems, such as the lack of funding for existing drainage infrastructure, and contribute to downstream flooding reduction. This paper also intends to encourage discussion about the methods for designing a stormwater fee in the academic community, which is still incipient.

Influence of drainage network and compensatory techniques on urban flooding susceptibility.

Urban flooding due to accelerated urbanization and the resulting drainage problems have become a worldwide issue and the subject of several studies in recent decades. Alternative and holistic approaches such as sustainable drainage systems have been gaining prominence. Compensatory techniques represent one of these promising alternatives for managing flooding risk in the transition to regenerative urban environments. The goal of this study is to assess the effect of a drainage network together with compensatory techniques on the susceptibility to urban flooding in Campeche District. This study applies the analytical hierarchy process together with a consistency analysis, using overlapping influential parameters in three scenarios. The results show that introducing a drainage system decreases the susceptibility to urban flooding in approximately 27% of Campeche District. In general, considering the absence of a drainage network, it is concluded that its implementation together with compensatory structures provides a reduction of approximately 32% in the susceptibility to urban flooding. It should be noted that, although costly, interventions for the implementation of a drainage infrastructure associated with compensatory techniques are extremely important for disaster reduction and sustainable development.

Use of shrimp shell for adsorption of metals present in surface runoff.

This research analyzes the use of natural shrimp shell and commercial chitin for biosorption of metal ions in surface runoff. Investigation of the use of these biosorbent materials in drainage systems becomes a management measure for two extremely important issues in Brazil, fish waste management and the surface runoff quality. Methodological procedures involved treatments with different amounts of unprocessed shrimp shell and commercial chitin (5g and 10g) for 200mL of a compensatory drainage mechanism (infiltration swale). The contact time of biosorbent and runoff was 24h and removal of metal ions Fe, Mn, Zn, Cu, Ni, Pb, and Cr was studied. Tests with unprocessed shrimp shell showed high concentrations of metallic ions (Pb, Ni, and Cu) causing contamination of the environment. However, the two biosorbents presented good removal of specific metallic ions (Fe, Mn, Zn, and Cr). These results indicate the need for a biosorbent pre-treatment prior to full-scale use. We indicate the need for a more detailed investigation of water quality in the environment used for shrimp farming. Tests with commercial chitin presented satisfactory results for two concentrations tested. Tests with 10g of commercial chitin allowed removal of all tested metal ions (Fe, Mn, Zn, Cu, Ni, Pb, Cr) with removal percentage between 6.7% and 84.4%. This efficiency may be related to the chitin's composition (shrimp, crustaceans, and crab) and to the chemical process applied to the product prior to commercialization.

Application of Systems Thinking to the assessment of an institutional development project of river restoration at a campus university in Southern Brazil.

Rapid urban growth and high population density have become a problem for urban water resources, especially in developing countries. In general, the pollution of rivers and degradation of ecosystems are the result of both management failures and lack of sewage treatment. River restoration appears as a solution to improve this scenario, but it is common for there to be an absence of a systemic vision in these projects. Thus, this work analysed one of these projects as an initial approach to create coherent (qualitative) shared perspectives on the same problem. This project was developed in a Brazilian university territory in response to a Public Civil Action. Rivers within the university surroundings are degraded due to sewage disposal and wastewater pollution from external and internal sources within the university, but the programme actions contemplate only interventions within the perimeter of the university while excluding the other parts of its watershed. We analyse this problem under a Systems Thinking approach by using causal loop diagrams, being clear that ecosystems cannot be reduced to territorial limits only. The systemic map shows many actions that contribute to the water quality degradation, with emphasis on illegal dumping of wastewater (sewage) and land use change in the upstream areas prior to the university. Point measures are palliative and do not guarantee the quality of river water. Regulation of impervious surfaces and correct disposal of wastewater can improve the current panorama, but greater integration between stakeholders and other key actors is required.

Applications of life cycle assessment and cost analysis in health care waste management.

The establishment of rules to manage Health Care Waste (HCW) is a challenge for the public sector. Regulatory agencies must ensure the safety of waste management alternatives for two very different profiles of generators: (1) hospitals, which concentrate the production of HCW and (2) small establishments, such as clinics, pharmacies and other sources, that generate dispersed quantities of HCW and are scattered throughout the city. To assist in developing sector regulations for the small generators, we evaluated three management scenarios using decision-making tools. They consisted of a disinfection technique (microwave, autoclave and lime) followed by landfilling, where transportation was also included. The microwave, autoclave and lime techniques were tested at the laboratory to establish the operating parameters to ensure their efficiency in disinfection. Using a life cycle assessment (LCA) and cost analysis, the decision-making tools aimed to determine the technique with the best environmental performance. This consisted of evaluating the eco-efficiency of each scenario. Based on the life cycle assessment, microwaving had the lowest environmental impact (12.64 Pt) followed by autoclaving (48.46 Pt). The cost analyses indicated values of US$0.12 kg(-1) for the waste treated with microwaves, US$1.10 kg(-1) for the waste treated by the autoclave and US$1.53 kg(-1) for the waste treated with lime. The microwave disinfection presented the best eco-efficiency performance among those studied and provided a feasible alternative to subsidize the formulation of the policy for small generators of HCW.

Avaliação da influência do etanol sobre o grau de volatilização BTEX em solos impactados por derrames de gasolina/etanol / Evaluation of the ethanol influence over the volatilization grade of BTEX in soil impacted by gasoline/ethanol spills

O principal objetivo deste trabalho foi a avaliação quantitativa da influência do etanol sobre a volatilização de BTEX (benzeno, tolueno, etilbenzeno e xilenos) em mistura de gasolina e etanol anidro 25 por cento (v/v) em colunas experimentais, que simularam solos contaminados com gasolina pura e gasolina/etanol. Todos os BTEX apresentaram expressivo aumento das taxas de volatilização na coluna contendo a mistura gasolina/etanol. Porém, em termos percentuais, o maior e menor aumento nas taxas de volatilização foi observado para tolueno e benzeno, respectivamente. Em amostras de controle, com o percentual de etanol variando entre 0 e 25 por cento, não foi observado aumento no grau de volatilização do etilbenzeno, enquanto que o grau de volatilização dos xilenos foi reduzido. Estes resultados sugerem que, além de forças de interação intermoleculares, efeitos de interação líquido/estrutura do solo podem estar exercendo importante papel na volatilização dos BTEX.

The main objective of this paper was the quantitative evaluation of the ethanol's influence about the volatilization of BTEX (benzene, toluene, ethylbenzene and xylenes) in a mixture of gasoline and anhydrous ethanol 25 percent (v/v) in experimental columns that simulated soil contamination with gasoline/ethanol. All the BTEX presented expressive increase of volatilization rates in the gasoline-ethanol column. However, in terms of percentage, the highest and lowest volatilization grades were observed for toluene and benzene, respectively. In batch tests (control samples), with mixtures of gasoline ethanol with 0 and 25 percent (v/v) in ethanol, no increase of the volatilization grade was observed for ethylbenzene and the volatilization grade for xylenes was reduced. Matrix effects seem to be, besides the intermolecular interaction forces, important contributions for the volatilization grade of BTEX in this kind of sample.

Estudos sobre a oxidação aeróbia do metano na cobertura de três aterros sanitários no Brasil / Studies on the aerobic methane oxidation at three sanitary landfills covers in Brazil

A oxidação biológica e aeróbia do metano em materiais de cobertura de aterros de resíduos sólidos urbanos é uma das alternativas para se minimizarem as emissões dos gases de efeito estufa. Este artigo tem como objetivo avaliar a oxidação biológica do metano em material de cobertura de três aterros brasileiros (dois municipais e uma célula experimental). O trabalho consistiu na coleta de amostras dos solos, as quais foram caracterizadas através de ensaios geotécnicos e microbiológicos. Em laboratório, avaliou-se o consumo de metano de uma amostra de cada aterro. Os resultados revelaram a presença de bactérias metanotróficas e consumo de metano em laboratório, o que sugere que exista uma relação inversa entre o grau de saturação no momento da coleta e o número de bactérias metanotróficas.

The biological and aerobic oxidation of methane within the soil cover of municipal solid waste landfills is one an alternative to minimize emissions of greenhouse effect gases. This study aims at assess the biological oxidation of methane within the final cover of three landfills in Brazil (two municipal ones and one experimental cell). The soil samples obtained from the landfill cover were characterized by geotechnical and microbiological tests. In the laboratory the consumption of methane from each sample were evaluated. The results revealed the presence of methanotrophic bacteria and consumption of methane in the laboratory was observed, which also suggest that there is an inverse relation between the degree of saturation at the time of sampling and the number of methanotrophic bacteria.