Search results for "Biomas"
showing 10 items of 980 documents
Embodied energy and environmental impacts of a biomass boiler: a life cycle approach
2015
The 2030 policy framework for climate and energy, proposed by the European Commission, aims towards the reduction of European greenhouse gas emissions by 40% in comparison to the 1990 level and to increase the share of renewable energy of at least the 27% of the European's energy consumption of 2030. The use of biomass as sustainable and renewable energy source may be a viable tool for achieving the above goals. However, renewable energy technologies are not totally clean because they cause energy and environmental impacts during their life cycle, and in particular they are responsible of air pollutant emissions. In this context, the paper assesses the energy and environmental impacts of a …
Modelling and dynamic simulation of hybrid moving bed biofilm reactors: model concepts and application to a pilot plant.
2011
In the recent years, there has been an increasing interest in the development of hybrid reactors, especially in the up-grading of existing activated sludge plants that are no longer able to comply with concentration limits established by regulatory agencies. In such systems the biomass grows both as suspended flocs and as biofilm. In this way, it is possible to obtain a higher biomass concentration in the reactor, but without any significant increase of the load to the final clarifier. The paper presents the setting-up of a dynamic mathematical model aimed at quantitatively describing the biokinetic processes occurring in a hybrid moving bed biofilm reactor (HMBBR), and, more in general, in…
Hybrid moving bed biofilm reactors: a pilot plant experiment.
2008
The growing increment of the urbanization and on the other hand, the even more strict effluent limits imposed by the Water Framework Directive for the receiving water body quality state have lead to a need of upgrading several existing WWTP. With this respect HMBBR systems are an innovative solution since allow to upgrade existing high loaded WWTP without building new tanks. However, some uncertainties in their design, maintenance as well as performance have to be addressed due to their recent acquisition compared with well consolidated technologies such as activated sludge systems. In this light, a data gathering campaign on a HMBBR pilot plant has been performed. The aim was to detect the…
Modelling of hybrid moving bed biofilm reactors: a pilot plant experiment.
2007
In recent years there has been an increasing interest in the development of hybrid biofilm reactors, especially in the upgrading of existing WWTP that are no longer able to respect concentration limits. In fact, today's challenge is the achievement of a good aquatic state for the receiving water bodies according to the Water Framework Directive requirements, which indeed limit even more the continuous emissions, i.e. coming from WWTP. This paper presents the setting up of a mathematical model for the simulation of a hybrid MBBR system; the model calibration/validation has been carried out considering a field gathering campaign on an experimental pilot plant. The main goal is to gain insight…
Consensus based distributed estimation of biomass concentration in reverse osmosis membranes
2015
The correct estimation of biofilm formation in industrial environments, such as reverse osmosis plants, has become a topic of great interest. The occurrence of this natural process is the cause of huge economic losses due to a decrease of performance and maintenance costs in these plants. Current solutions based on water pretreatment or the dozing of biocides are not effective due to the lack of information about the state of the biofilm in the water system. In this work, we propose the use of a wireless sensor network that, based on the measurement of the biofilm thickness growth at the substratum of each sensor, estimates the biomass concentration within the biofilm, and, eventually, the …
Energy and environmental impacts of Energy related products (ErP): a case study of biomass-fuelled systems
2014
Abstract Energy-related Products (ErP) account for a large proportion of European energy and natural resource consumption. In 2007, ErP were responsible for the consumption of about 239 Mtoe of electricity and about 555 Mtoe of fuels. In order to reduce the energy and environmental impacts of these products, the European Commission published the Directive 2009/125/EC on the eco-design of ErP. This Directive represents a key component of European policy for improving the energy and environmental performances of products in the internal market. In this context, it is important to develop scientific research aimed at assessing the energy and environmental impacts of ErP, and at defining their …
Nonlinear control of an activated sludge aeration process: use of fuzzy techniques for tuning PID controllers
1999
In this paper, several tuning algorithms, specifically ITAE, IMC and Cohen and Coon, were applied in order to tune an activated sludge aeration PID controller. Performance results of these controllers were compared by simulation with those obtained by using a nonlinear fuzzy PID controller. In order to design this controller, a trial and error procedure was used to determine, as a function of error at current time and at a previous time, sets of parameters (including controller gain, integral time and derivative time) which achieve satisfactory response of a PID controller actuating over the aeration process. Once these sets of data were obtained, neural networks were used to obtain fuzzy m…
Partial stability for specific growth rate control biotechnological fed-batch processes
2004
In this paper, the problem of the specific growth rate control in biological reactions in fed-batch mode is dealt with. It is assumed that only part of the state is measurable on-line, namely biomass and volume. Moreover, no estimation of the specific growth rate is used. An unbounded manifold is tracked using a partial state feedback. Then, techniques for partial stability, i.e., only with respect to part of the variables, are used in order to analyze the problem.
Assessing the gasification potential of five woodchips species by employing a lab-scale fixed-bed downdraft reactor
2015
Abstract This paper is aimed to assess the performance of air blown fixed-bed downdraft gasification of local lignocellulosic biomasses which in perspective of Southern Norway are both available and sustainable. Long rotation forest crops birch, oak and spruce, coupled with energy crops poplar and willow were used as feedstocks. The gasification conditions undertaken were widely varied in-terms of air (∼3.20–4.20 N m3/h) and fuel flow (∼1.70–2.10 kg/h) so that the corresponding equivalence ratio (ER) differed (0.19–0.80) and ultimately reflected to other operational parameters such as bed temperature (∼550–760 °C maximum), producer gas yield (∼1.50–2.30 N m3/kg, wet base), cold gas efficien…