Deliverable 4.5 - Report on occupational health and safety assessment in the PHA production plant

Abstract

INAIL task is the study of the occupational risk for the workers who are involved in the production process of PHA from bio-waste. OH&S aspects related to the organic fraction of municipal solid waste and sewage sludge, during pretreatment steps, were not considered because the process of PHA production integrates into well-known and consolidated biowaste working cycles, where the occupational risks have already been assessed and managed in the existing industrial plants, in accordance with the provisions of European Regulations in the field of H&S. INAIL task has been developed starting from data on PHA production process obtained by RES URBIS Task 2.2 in which the task leader, UNIRM, and its contributors: NOVAID, UNIVE, IRSA, have optimized the feeding/harvesting strategy for PHA production in the SBR plants.

Biological risk

The biological risk of the process stages for the production of PHA has been assessed according to European directive 2000/54/EC. The methodological approach proposed is for the activities that are not allocated to a safety level (non-safety level activities), such as those for the PHA production process at Treviso pilot-plant. The biohazard assessment has taken into account 1) the DNA sequences of the PHA-producing bacteria for the taxonomical characterization of the selected biomass during the different phases in PHA production; 2) the biohazard risk-classification of the biological agents monitored which could pose a hazard for human health. The biological risk assessment has taken into account the epidemiological data on the work-related health outcomes for similar exposures (e.g. wastewater treatment plants) considering not only infection risk but also the potential allergic and toxic effects of the microorganisms and/or their parts.

Potentially explosive atmospheres

The analysis has been focused on assessment of formation of potentially explosive atmospheres during the fermentation, which generates a flammable gaseous mixture into the fermenter. With reference to such hazard, lower flammability limit (LFL) of mixture has been calculated in every conditions of fermentation reactor operation. In order to ensure a safe fermenter operation some technical recommendations have been provided.

Chemical risk

The PHA production process has been analyzed in light of European legislative framework concerning the protection of workers from risks to safety and health arising from the effects of chemical agents that are present at the workplace or as a result of any work activity involving chemical agents. Occupational chemical risk assessment has been carried out applying a guideline drawn up by Italian National System for Environmental Protection. The guideline meets the requirements of Community legislation and the updates introduced by CE Regulation 1907/2006 (REACH Regulation) and CE Regulation 1272/2008 (CLP Regulation) and provides a methodology for chemical risk assessment distinguishing between risks for safety and risks for health. For PHA extraction and purification steps, the use of solvents alternative to halogenated substances have been addressed both analyzing some green solvent selection guides and introducing the inherent safety index approach which could lead to a ranking of a number of potential extraction solvents with the final aim to ease the best choice to be applied at industrial full scale plant level.