Real time material flow monitoring in mechanical waste processing and the relevance of fluctuations.

To achieve the goals of the circular economy, significant improvements in non-hazardous solid waste processing/treatment must be made. Large deficits in the digitalization of mechanical waste treatment plants (smart waste factory) offer great potential for improvement. Real-time material flow monitoring is carried out in very few plants, thus wasting considerable potential for improving plant performance. This article describes results from the authors' own practical analyses using sensor-based technologies for monitoring material flows, an on-site investigation in a large waste treatment plant and also in a pilot-scale plant (Technical Line 4.0) using mixed commercial waste (MCW) from Austria. The obtained data shows that the quantitative monitoring of volume and mass flow (via laser triangulation as well as near-infrared (NIR) based monitoring) and material composition (NIR sensor) is possible. The observed fluctuations were categorised in short-, mid- and long-term fluctuations and were led back to their causes, i.e. discontinuous feeding process, material and machine-specific characteristics. Using the quotient of the 90% (Q90) and 10% (Q10) quantiles of time-resolved volume-flow data for the assessment of fluctuations, for the considered time-intervals, resulted in Q90 / Q10 ratios between 3.39 and 4.58. If short-term fluctuations (within the observed time-intervals) are related to the 29.6 s moving average, deviations between 1.8% and 6.8% result. To verify the relevance of such fluctuations, sensor-based sorting (SBS) experiments were conducted, revealing a reduced product purity of 6% due to short-term fluctuations in the feed of the SBS-Machine using light packaging waste (LPW).

Determination of bacterial and fungal bioaerosols in municipal solid-waste processing facilities of Tehran.

PURPOSE: The concentration and distribution characteristics of airborne bacteria and fungi were assessed at municipal solid-waste processing and disposal facilities (SWPDFs) of Tehran (Arad Kouh Site). METHODS: Air samples were obtained from the indoor air of a laboratory and refectory as well as from the air surrounding a conveyor belt, rotary screen, and bailer. Sampling was conducted according to the standard procedure to determine two bacterial species (Klebsiella spp. and Staphylococcus aureus), total bacteria and fungi, and Aspergillus fumigates. RESULTS: The maximum concentration of Staphylococcus aureus was in the air surrounding the conveyer belt with the average of 993.2 CFU/m3. The highest concentrations of total fungi (4958.8 CFU/m3) and Aspergillus fumigates (2114 CFU/m3) were measured in the air surrounding the rotary screen. The mean concentrations of bacterial bioaerosols in a more contaminated sampling location in summer and winter were 1687.6 and 1479.4 CFU/m3, respectively. CONCLUSIONS: There were significant differences between the concentration of bioaerosols in cold and warm seasons. The concentrations of bioaerosols in the air surrounding the rotary screen and conveyer belt were significantly more than those in other sampling locations, but were within the recommended maximum of 103 and 104 CFU/m3.

Liver and kidney serum profile abnormalities in workers exposed to aflatoxin B1 in urban solid waste management centers.

Many workers are exposed to health problems arising from molds, fungi, and their toxins during waste processing. Aflatoxin B1 (AFB1) level in airborne and settled dust, aflatoxin B1-albumin (AFB1-Alb) adduct in serum, liver and kidney biochemical tests, and body redox change of workers in municipal dry waste-processing sites were investigated. The surface, personal, and area air dust and the blood of workers' samples were collected from the plastic and bread waste-sorting sections in three recycling municipal dry waste sites. Digestion (only for serum samples), passed through SPE cartridge, elution, and collection with methanol, immune-affinity column clean-up, and HPLC system equipped with post-column derivatization method and fluorescence detection were performed for determination of AFB1 and AFB1-Alb levels in the samples. The mean level of dust and AFB1 in the personal and area air, and in the settled dust and the AFB1-Alb in the serum of workers in the bread waste sorting, was higher than plastic waste-sorting samples, in all of the sites. The differences in the biochemical profiles of subjects exposed to aflatoxin B1 as compared to the control group especially in liver and kidney function parameters as well as antioxidant factors of the serum were significant. The workers in handling of municipal waste may be exposed to potentially hazardous levels of aflatoxin B1. The adverse effects of AFB1 on the kidney and liver may be caused by changes in the redox system.

A análise multicritério de tecnologias utilizadas na gestão de resíduos sólidos urbanos

O presente trabalho analisou a aplicação do método de avalia-ção multicritério como ferramenta de auxilio a escolha de tecnologias de tratamentode RSU, considerando as características, vantagens e desvantagensdas tecnologias disponíveis para tratamento dos RSU; assim como critériospara escolha das tecnologias mais adequadas para tratamento de resíduossegundo a Análise Multicritérios (AHP); além disso, analisou as possíveis combinaçõesde tecnologias para tratamento. Como metodologia de pesquisa, aplicou-sea revisão bibliográfica, e para a aplicação do método de analise multicritério,consultaram-se especialistas na área de gestão de resíduos sólidos urbanos.Esta consulta se realizou através do preenchimento de formulários (apêndiceII) por especialistas da área, sem que suas identidades e formações fossemde conhecimento do pesquisador, de modo a evitar que suas respectivasformações pudessem influenciar a interpretação dos dados. Todavia, comoforma de considerar a experiência de cada especialista, houve outra forma deconsultá-los, de modo paralelo a análise AHP. Desta forma, tornou-se comparara aplicação do método AHP com uma consulta direta. As possibilidades detratamento de resíduos sólidos urbanos foram organizadas segundo os custosprincipais envolvidos, que são os custos de coleta (com ou sem segregação deresíduos na fonte geradora), custos internos do empreendimento e custos externos.As tecnologias consideradas foram o uso de aterros sanitários, a incineraçãocombinada com o tratamento biológico dos resíduos e a incineração indissociadadestes mesmos resíduos. Como resultados, evidenciou-se que nãohá um consenso entre os especialistas quanto ao uso de tecnologias de tratamentode resíduos sólidos urbanos.

The present work analyzed the application of the multicriteriaevaluation method as a tool to assist in the selection of MSW treatment technologies,considering the characteristics, advantages and disadvantages of theavailable technologies for MSW treatment; as well as criteria for choosing themost appropriate technologies for waste treatment according to MulticriteriaAnalysis (AHP); in addition, analyzed the possible combinations of technologiesfor treatment. As a research methodology, the literature review was applied,and for the application of the multicriteria analysis method, specialists wereconsulted in the area of urban solid waste management. This consultation wascarried out by filling in forms (appendix II) by experts in the field, without theiridentities and formations being known to the researcher, in order to avoid thattheir respective formations could influence the interpretation of the data. However,as a way of considering the experience of each specialist, there was anotherway of consulting them, in parallel to the AHP analysis. In this way, it becamepossible to compare the application of the AHP method with a directquery. The possibilities of urban solid waste treatment were organized accordingto the main costs involved, which are collection costs (with or without segregationof waste at the generating source), internal costs of the project andexternal costs. The technologies considered were the use of landfills, incinerationcombined with the biological treatment of waste and the incineration withoutthe associated waste. As results, it was evidenced that there is no consensusamong the experts regarding the use of urban solid waste treatment technologies.