12 research outputs found
A História da Alimentação: balizas historiográficas
Os M. pretenderam traçar um quadro da História da Alimentação, não como um novo ramo epistemológico da disciplina, mas como um campo em desenvolvimento de práticas e atividades especializadas, incluindo pesquisa, formação, publicações, associações, encontros acadêmicos, etc. Um breve relato das condições em que tal campo se assentou faz-se preceder de um panorama dos estudos de alimentação e temas correia tos, em geral, segundo cinco abardagens Ia biológica, a econômica, a social, a cultural e a filosófica!, assim como da identificação das contribuições mais relevantes da Antropologia, Arqueologia, Sociologia e Geografia. A fim de comentar a multiforme e volumosa bibliografia histórica, foi ela organizada segundo critérios morfológicos. A seguir, alguns tópicos importantes mereceram tratamento à parte: a fome, o alimento e o domínio religioso, as descobertas européias e a difusão mundial de alimentos, gosto e gastronomia. O artigo se encerra com um rápido balanço crítico da historiografia brasileira sobre o tema
Estimating the post-closure management time for landfills containing treated MSW residues.
The Landfill Directive will require the pre-treatment of MSW prior to landfilling.
The removal of progressively increasing proportions of the biodegradable fractions from
landfilled waste, and the UK Government’s commitment to increase recycling of key waste
fractions, will lead to an inevitable change, from the disposal of raw MSW, to the disposal of
MSW treatment residues, to landfill. This will undoubtedly change the type and rate of
emissions from landfills. The question that this research project has sought to answer is “how
long will active management be required for different MSW treatment residues?” The term
equilibrium status has been used to define the end point beyond which management of wastes is
no longer necessary. Calculating the equilibrium status of waste involves an assessment of the
landfill gas emissions, leachate quality and hydraulic status of the landfill. These key parameters
change with time as the landfill evolves. Equally, the engineering performance of a site is also
changing with the gradual degradation of the liner and capping systems. The question posed
above is therefore not easily answered
Achieving equilibrium status and sustainable landfill - the holy grail?
This paper presents the results of a research contract jointly funded by the
Environment Agency and ESART examining the residues of likely post-Landfill Directive waste
streams that will need to go to landfill and the time taken to achieve sufficient stabilisation such
that management controls can be removed. The first part of the project has identified a number
of processes that are likely to be adopted by the waste management industry in order to meet the
biodegradable waste diversion targets. Both leachate quality and landfill gas generation data has
been assessed for each residue stream. Forward modelling has been undertaken on these data
using LandSim2.5 within GoldSim to assess the likely period of management needed in order to
achieve equilibrium status
A strategy for emissions based regulation of landfill gas.
The Environment Agency (the Agency) is responsible for the regulation of
landfill sites in England and Wales. Since its formation, the Agency’s
regulatory strategy for landfill gas has been to require operators to
demonstrate best practice. However, this approach does not allow environmental
outcomes from site-specific landfill gas management to be easily illustrated or
quantified. Greater clarity is now given to these environmental outcomes by
augmenting best practice regulation of landfill gas with emissions-based
regulation. This will require a “step change” in the management of landfill gas.
However, it will enable the operator and regulator alike to respond to public
concerns regarding landfill gas, including increasingly complicated health-
related
Spray irrigation of landfill leachate: estimating potential exposures to workers and bystanders using a modified air box model and generalised source term
Generalised source term data from UK leachates and a probabilistic exposure
model (BPRISC4) 12 were used to evaluate key routes of exposure from chemicals
of concern during the spraying 13 irrigation of landfill leachate. Risk
estimates secured using a modified air box model are reported 14 for a
hypothetical worker exposed to selected chemicals within a generalised
conceptual exposure 15 model of spray irrigation. Consistent with pesticide
spray exposure studies, the key risk driver is 16 dermal exposure to the more
toxic components of leachate. Changes in spray droplet diameter 17 (0.02-0.2 cm)
and to spray flow rate (50-1000 l/min) have little influence on dermal exposure,
18 although the lesser routes of aerosol ingestion and inhalation are markedly
affected. The risk 19 estimates modelled using this conservative worst case
exposure scenario are not of sufficient 20 magnitude to warrant major concerns
about chemical risks to workers or bystanders from this 21 practice in the
general sense. However, the modelling made use of generic concentration data for
22 only a limited number of potential landfill leachate contaminants, such that
individual practices 23 may require assessment on the basis of their own merits
Estimating Pollutant Removal Requirements for Landfills in the UK: III. Policy Analysis and Operational Implications.
The policy analysis and management implications for achieving landfill
equilibrium status within a sustainable timescale (decades rather than
centuries) are presented based on modelled results reported previously. Until
relatively recently, timescale estimates suggested that equilibrium or landfill
completion could be achieved within 40-60 years i.e. the same order of magnitude
as financial provision for aftercare. However results of modelling in this study
(reported in previous paper) suggest that timescales may be considerably longer
(many centuries in some instances) suggesting that financial provision may be
inadequate. The role of the most promising and available waste treatment
technologies and strategic waste management options in contributing towards
achieving equilibrium status are discussed. Results suggest that a re-
examination of techniques for accelerating landfill stabilisation, including
aerobic and bioreactor landfill, is warranted
Assessment of municipal waste compost as a daily cover material for odour control at landfill sites.
The ability of municipal waste compost as a daily cover material to reduce the
odorous emissions associated with landfill surfaces was investigated. Trials
were carried out using landfill gas, a certified sulphurous gas mix and ambient
air as a control. Odorous gas was passed through portable test column filled
with compost at different densities (590 kg/m3 and 740 kg/m3). Gas samples were
taken from the inlet, outlet and at varying column depths and examined using a
combination of sensory analysis (olfactometry) and a novel analytical method
(Transportable Selected Ion Flow Tube – TSIFT). Results for the trials using
landfill gas showed a 69% odour reduction (OU/m3) through the column for compost
with a bulk density of 590 kg/m3, and a reduction of 97% using compost with a
bulk density of 740 kg/m3. TSIFT analysis showed an overall decrease in the
concentration of terpenes, and sulphurous compounds in the outlet gas from the
column for both bulk densities. No significant trend could be identified for the
concentrations at different depths within the column. Results show the ability
of compost to reduce landfill odours under differing conditions. The
inconclusive data provided by TSIFT analysis may be due to the analysis of
compounds that are not contributing to odour, and thus highlights the potential
for synergetic effects and the importance of sensory measurement when examining
odorous emissio
Estimating Pollutant Removal Requirements for Landfills in the UK: II. Model Development
A modelling methodology using a leachate source term has been produced for
estimating the timescales for achieving environmental equilibrium status for
landfilled waste. Results are reported as the period of active management
required for modelled scenarios of non-flushed and flushed sites for a range of
pre-filling treatments. The base scenario against which results were evaluated
was raw municipal solid waste (MSW) for which only cadmium failed to reach
equilibrium. Flushed raw MSW met our criteria for stabilisation with active
leachate management for 40 years, subject to each of the leachate species being
present at or below their average UK concentrations. Stable non-reactive wastes,
meeting EU waste acceptance criteria, fared badly in the non-flushed scenario,
with only two species stabilising after a management period within 1000 years
and the majority requiring >2000 years of active leachate management. The
flushing scenarios showed only a marginal improvement, with arsenic still
persisting beyond 2000 years management even with an additional 500 mm y−1 of
infiltration. The stabilisation time for mechanically sorted organic residues
(without flushing) was high, and even with flushing, arsenic and chromium
appeared to remain a problem. Two mechanical biological treatment (MBT)
scenarios were examined, with medium and high intensity composting. Both were
subjected to the non-flushing and flushing scenarios. The non-flushing case of
both options fell short of the basic requirements of achieving equilibrium
within decades. The intense composting option with minimal flushing appeared to
create a scenario where equilibrium could be achieved. For incinerator bottom
ash (raw and subjected to various treatments), antimony, copper, chloride and
sulphate were the main controls on achieving equilibrium, irrespective of
treatment type. Flushing at higher flushing rates (500 mm y−1) failed to
demonstrate a significant reduction in the management period requ
Charaterisation of treated wastes to support an evidence base for sustainable waste management.
Defra must consider policies and strategies to manage environmental challenges
such as climate change and sustainability. At a basic level the strategies need good quality data
on waste characteristics. The dataset for UK wastes, in particular the new generation of treated
wastes, is not fit for this purpose. This paper outlines the gaps in knowledge needed to underpin
policy development and initial findings from a new project funded under Defra’s Waste and
Resource Management Research Programme. The project team from WRc, Open University and
Cranfield University aims to improve understanding of the characteristics of treated organic and
inorganic wastes, methods of testing and knowledge of treatment process performance. Potential
opportunities from the research are also described. New data will be collated into the
presentation
Estimating Pollutant Removal Requirements for Landfills in the UK: I. Benchmark Study and Characteristics of Waste Treatment Technologies
Introduction of the EU Landfill Directive is having a significant impact on
waste management in the UK and in other member states that have relied on
landfilling. This paper considers the length of the aftercare period required by
the municipal solid waste streams that the UK will most probably generate
following implementation of the Landfill Directive. Data were derived from
literature to identify properties of residues from the most likely treatment
processes and the probable management times these residues will require within
the landfill environment were then modelled. Results suggest that for chloride
the relevant water quality standard (250 mg l−1) will be achieved with a
management period of 40 years and for lead (0.1 mg l−1), 240 years. This has
considerable implications for the sustainability of landfill and suggests that
current timescales for aftercare of landfills may be inadeq