Patrícia Bilotta

Swine manure post-treatment technologies for pathogenic organism inactivation

Swine manure agricultural use is a common practice in Brazil. Their physic-chemical characteristics favor its use as biofertilizer, but the presence of pathogens may become a risk to human health. This research presents a qualitative study of the main alternatives of pig manure disinfection, analyzing efficiency, advantages and limitations of each procedure. The disinfection studies reported in literature are based on the following treatments: alkaline, thermal, biological, chemical, and physical. The greater efficiencies are in thermal treatment (> 4 log: 60 °C), chemical treatment (3 to 4 log: 30mg Cl- L-1; 3 to 4 log: 40 mg O3 L-1) and physical treatment (3 a 4 log: 220 mJ UV radiation cm-2). The biological treatment (anaerobiosis) also promotes the pathogen reduction of swine manure, however with lower efficiency (1 to 2 log). The selection of the treatment should consider: implementation and operation cost, necessity of preliminary treatment, efficiency obtained and destination of the treated manure (agricultural use, water reuse). Brazilian regulation does not have specific guidelines for the microbiological quality of animal production effluents that is very important to be considered due to confined animal feeding operation transformation in the last years in the country.

Influência do combustível (diesel e biodiesel) e das características da frota de veículos do transporte coletivo de Curitiba, Paraná, nas emissões de NOx

The public transportation system in Curitiba, Parana, Brazil, is recognized by its innovative solutions; and is a model for Brazil. In this work, the influence of fuel (diesel and biodiesel) and the conditions of the public transport vehicle fleet of Curitiba in NOx emissions was assessed, and this is a pioneered initiative. A total of 188 vehicles (9.7% of the total) with engines of 7 and 12 L were selected, named B7R, B10M, B12M and B215RH, and measurements of NO and NO2 were performed in the exhaust output. In relation to the type of fuel, the emissions of NO and NO2 for biodiesel (B100) were, respectively, 37 and 26% superior to the values observed with the fuel diesel (S10). Comparing the engines B12M with up to 3 and 10 years of operation, the average emissions of NOx were close to 40% higher. Thus, it was possible to observe that the biodiesel vehicles had higher NOx emissions when compared with diesel vehicles in similar conditions of operation and engine wear time. Therefore, although the use of biodiesel brings environmental advantages, as renewable fuel, new technologies and devices must be developed to control emissions of NO and NO2 in engines that use this type of fuel. For future works the authors recommend tests on dynamometer to simulate NOx emission in diesel and biodiesel engine in different conditions of charge and engine speed.

Estimativa de geração de energia e emissão evitada de gás de efeito estufa na recuperação de biogás produzido em estação de tratamento de esgotos

The use of biogas from treatment of domestic sewage, animal waste and solid waste disposal is an alternative to generate electricity with great potential for expansion in Brazil. The aim of this paper is quantifying the energy from the biogas produced in a wastewater treatment plant (WWTP) and estimating the greenhouse gas emission avoided with the biogas recovery. The WWTP evaluated has flow 33,220.8 m3.d-1 and COD 14,617.1 kg.d-1 and serves about 190,000 inhabitants. It was used monitoring data from August/2012 to March/2013 to quantify the following parameters: COD converted into biomass; sulfate converted to sulfide; COD converted to methane; methane loss (liquid and gas); potential energy available; electrical power available; avoided emissions of methane. The following results were obtained: average treatment efficiency of 65.6%; methane production of 1,427.2 m3.d-1; average electricity available of 65,280.3 kWh.month-1 (59% of the average monthly energy demand of the WWTP); avoided emissions of 941.9 kgCH4.d-1 and 17,189.7 kgCO2 eq.d-1. Therefore, it can be concluded that the biogas recovery of in Santa Quiteria WWTP can result in economic and environmental benefits.

Estimate of energy generation and of greenhouse gas emission on biogas recovery from wastewater treatment plant

The use of biogas from treatment of domestic sewage, animal waste and solid waste disposal is an alternative to generate electricity with great potential for expansion in Brazil. The aim of this paper is quantifying the energy from the biogas produced in a wastewater treatment plant (WWTP) and estimating the greenhouse gas emission avoided with the biogas recovery. The WWTP evaluated has flow 33,220.8 m.d and COD 14,617.1 kg.d and serves about 190,000 inhabitants. It was used monitoring data from August/2012 to March/2013 to quantify the following parameters: COD converted into biomass; sulfate converted to sulfide; COD converted to methane; methane loss (liquid and gas); potential energy available; electrical power available; avoided emissions of methane. The following results were obtained: average treatment efficiency of 65.6%; methane production of 1,427.2 m.d; average electricity available of 65,280.3 kWh.month (59% of the average monthly energy demand of the WWTP); avoided emissions of 941.9 kgCH 4 .d and 17,189.7 kgCO 2 eq .d. Therefore, it can be concluded that the biogas recovery of in Santa Quiteria WWTP can result in economic and environmental benefits.