The role of bio-mechanical treatments of waste in the dioxin emission inventories

Rada, Elena Cristina; Ragazzi, Marco; Panaitescu, Valeriu; Apostol, Tiberiu

doi:10.1016/j.chemosphere.2005.04.065

Cited by 31 publications

(15 citation statements)

References 2 publications

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“…In this frame the environmental impact of an incinerator depends on many factors:  Site characteristics (the local climatology strongly affects the local impact);  Amount of residual MSW (RMSW) to be treated (the off-gas flow-rate is proportional to the amount of RMSW burnt, if its characteristics are steady);  Lower Heating Value (LHV) of the RMSW (this parameter influence the off-gas flow-rate);  Emission concentrations at the stack during operating conditions (keeping steady the off-gas flow-rate, the release of pollutants at the stack is proportional to the pollutants concentrations at the emission);  Stack height (a higher stack fosters the pollutants dilution into the atmosphere);  Off-gas velocity at the stack (higher values of this parameter favor the dilution);  Off-gas temperature at the stack (this parameter is limited by the need of performing energy recovery, but it is clear that higher values foster dilution into the atmosphere);  Yearly operating hours (keeping steady the amount of waste to be fed, a shorter working period causes an increase of the waste flow-rate, with consequences on the peaks of impact). In the literature, an analysis of the effects of the operating hours scheduling is not common both for thermochemical processes [4,5] and for biochemical processes [6][7][8][9][10][11]. The aim of this paper is to go beyond the analyses based on overall balances [12,13].…”

Section: Introductionmentioning

confidence: 99%

Maintenance strategies and local impact of MSW incinerators

Ragazzi¹,

Torretta²,

Ionescu³

et al. 2013

Energy and Sustainability IV

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The present paper gives a contribution to the understanding of the effects of variations in maintenance scheduling on the environmental impact of municipal solid waste incinerators. The proposed approach allows a vision of their impact beyond the conventional balances. The characteristics of a selected case study were put forward and discussed. A plant proposed for a region in the North East of Italy was chosen for the scheduling effects analysis because of the long period of non-operation of each waste treatment line: 3 months per year as requested from the local environmental protection agency. The following effects were discussed on a yearly basis: maintenance stop fractionation, maintenance stop lasting, maintenance stop seasonal scheduling; the last aspect was discussed also at device level. The extreme scenario of seasonal stop gave the opportunity of assessing the highest reduction of yearly average impact from the stack, varying the season of maintenance: a reduction up to 23% could be obtained for the pollutants concentration contribution at ground level in the area of highest impact, comparing the worst case with the best case by a diffusive model. In the case of more common periods of stops for maintenance the reduction would be lower. The role of district heating must be taken into account too.

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Section: Introductionmentioning

confidence: 99%

Maintenance strategies and local impact of MSW incinerators

Ragazzi¹,

Torretta²,

Ionescu³

et al. 2013

Energy and Sustainability IV

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“…On the other hand, in terms of total WHO-TEQ concentrations, the A plant shows the lowest dioxin content with respect to the others. This behavior is due to the fact that the toxicity of the dominant congeners (1,2,3,4,6,7, is lower than the others ( Table 1). Considering that the WHO-TEQ concentrations are related to the toxicity for humans, no anomalies in PCDD/Fs were detected in the food chain for the potentially exposed population.…”

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confidence: 97%

“…For some PCDD/F congeners (e.g. 2,3,7,2,3,7,8,, the concentration measured in sewage sludge is lower than the instrumental detection limit (DL) for all the WWTPs considered. Conventionally, concentrations below the DL are assumed as half the DL itself (Table 1 and 2).…”

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confidence: 99%

Seeking Potential Anomalous Levels of Exposure to PCDD/Fs and PCBs through Sewage Sludge Characterization

M¹

2013

J Bioremed Biodeg

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An approach to detect anomalies in the exposure to Persistent Organic Pollutants (POPs) throughout the food chain is presented. The proposed method is useful also for preventing soil contamination by POPs that would require a remediation intervention. A steel making plant and its surrounding area were selected as a case-study. To investigate the possible effects of the plant on the settled population, sewage sludge samples from four wastewater treatment plants (WWTPs) were taken: one of these was chosen as reference for the population exposed to the emissions of the mill; the remaining three plants were chosen to provide background information about the POP content in sludge. No clear anomalies in dioxins (PCDD/Fs) were detected for the potentially exposed population. In terms of Polychlorinated Biphenyls (PCBs), the steel plant-influenced WWTP showed a total concentration between 2.7 and 4.8-time higher than the other plants; in terms of equivalent toxicity, only slightly higher concentrations were found for the steel plant-influenced WWTP. Therefore, if considering acceptable the daily intake from the diet of the unexposed population, the absence of a dioxin and dioxin-like emergency in the area of the mill is demonstrated. This method represents an innovative and technically simple tool to assess situations of permanent exposure to POP levels that are higher than the background. throughout the human body [16,12], showing the significant role of bioaccumulation. Journal of Bior emediation & BiodegradationThe presence of organic [17,18] and inorganic [19,20] hazardous substances in sewage sludge has been object of investigation in several studies. Sewage sludge has also been studied as potential source of energy [21][22][23][24][25][26], and as raw material for conventional [27,28] and nonconventional products [29,30]. In addition to these applications, sewage sludge can be also used as source of information to seek potential anomalous levels of exposure of a population to POPs: indeed, the dominant exposure route of POPs released by the most important sources (e.g. steel making plants) is the emission into the atmosphere, the atmospheric deposition to farmlands and pastures, the consequent contamination of the food produced, the intake by humans, the excretion, the transportation to WWTPs and the POP concentration in sewage sludge; thus, analyses on the POP content of sludge samples offer an alternative, inexpensive and technically simple approach to assess the existence of critical situations of exposure to POPs. Several studies focused on the ambient air and deposition monitoring in areas where steel making plants were present and highlighted their evident influence in terms of PCDD/F contribution in the surroundings [31][32][33]. The present study is then intended to propose a methodology, in order to detect anomalies throughout the food chain, as a consequence of the release of POPs in air from significant sources and their subsequent deposition to farmlands and pastures.This study focuses on a ste...

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“…The environmental impact of the two processes is different: bio-drying is a biological process, thus its emissions are related both to volatilization/extraction of pollutants already existing in the MSW (dioxin (Rada et al [2]), dust, etc.) and to generation of pollutants (ammonia, TOC, etc.…”

Section: Process Comparisonmentioning

confidence: 99%

Municipal solid waste pre-treatment: a comparison between two dewatering options

Ragazzi¹,

Rada²,

Panaitescu³

et al. 2007

WIT Transactions on Ecology and the Environment, Vol 102

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In the field of Municipal Solid Waste (MSW) management, dewatering before combustion is adopted in particular cases. The aim is the modification of the waste characteristics in order to increase its LHV and allow an easier removal of glass, metals and other inert material. The process is named bio-drying when it is based on biological aerobic reactions; no auxiliary fuel is needed thanks to the exothermic reactions that develop under aerobic conditions. About 2.5 million t MSW /y will be bio-dried in 2006 when all the bio-drying plants under construction will be completed. When the process is based on an external supply of heat (generally obtained from auxiliary fuel), the option is named thermal drying. This is well developed for sewage sludge but less for MSW. In Italy we can find a few experiences of thermal drying on the oversieve from MSW automatic sorting. In this case the aim is the decrease of humidity for the production of Refuse Derived Fuel (RDF) as, according to the Italian regulation, the highest value of humidity for RDF is 25%. A few proposals of thermal drying have been proposed as a pre-treatment before combustion in two Italian towns where an incinerator has been planned. In both cases the proposal is integrated with the combustor (in order to use a part of the heat of the off-gases) and the aim is the preparation of the waste to an easier inert, glass and metals removal (for material recycling and for decreasing the impact of the incineration). The present paper shows a comparison between bio-drying and thermal drying taking into account MSW characteristics, environmental aspects, energy balances and costs. An additional comparison concerns the role of selective collection of biodegradable fraction in order to decrease the humidity of the residual MSW.

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The role of bio-mechanical treatments of waste in the dioxin emission inventories

Cited by 31 publications

References 2 publications

Maintenance strategies and local impact of MSW incinerators

Maintenance strategies and local impact of MSW incinerators

Seeking Potential Anomalous Levels of Exposure to PCDD/Fs and PCBs through Sewage Sludge Characterization

Municipal solid waste pre-treatment: a comparison between two dewatering options

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