Small wastewater treatment plants are often localized nearby tourist areas. Odour emissions are a major environmental issue in these plants and are considered to be the main cause of disturbance noticed by the exposed population. Odour measurement is carried out using analytical or sensorial methods. Sensorial analysis, being assigned to the “human sensor”, is the cause of a considerable uncertainty. In this study, a novel procedure based on highly innovative analytical tool was used to identify and characterise the odour sources and the volatile substances that cause annoyance in a SWWTP located in a sensitive area, with the aim to remove the subjective component in the measure of the odours and define the induced impact. At the same time key odour compounds are detected, and the relationship between their concentration and the performances of the plant are investigated. The sources and the main chemical substances responsible for the olfactory annoyances were identified. Results highlight the applicability of the highly innovative tool in odour emission monitoring. Around 39 different substances were detected, with almost half being smell relevant components as well as responsible. Dimethyl disulphide was identified as key compound connected to the efficiency of the process.

Effects of salt on anaerobic digestion are dosage-dependent. As salt is a widely used condiment in food processing, effects of salt are bound to be considered when food waste is digested. In this study, salt addition effects (0, 2, 4, 6, 9, 12 g∙L⁻¹) on biogas and methane yields and kinetics of biogas production were researched. Meanwhile, component characteristics (food waste featured in carbohydrate, protein and fat, respectively) and fermentation concentrations (5 and 8 gVS∙L⁻¹) were also taken into consideration. Results showed that 2–4 g∙L⁻¹ salt addition was the optimal addition dosage for AD systems as they not only have the maximum biogas and methane yields, but also the maximum vs. removal in most cases. Also, according to the results of a modified Gompertz model, which is used to predict biogas and methane production rates, suitable salt addition can accelerate biogas production, improving the maximum biogas production rate (R_max). Factorial design (2 × 2) proved that interaction of salt and fermentation concentrations was significant for food waste featured with carbohydrate and with protein (p < 0.05). High salt addition and fermentation concentration can break the AD system when the feeding material was food waste featured with carbohydrate, but for food waste featured with protein, interaction of fermentation concentrations and salt addition can alleviate inhibition degrees.

This study examines the environmental impacts of informal e-waste recycling processes in Agbogbloshie, Ghana, which is one of the most notorious e-waste recycling sites in sub-Saharan Africa. Despite being unsafe and unorganized, the informal sector is still actively involved in dismantling, extracting, and disposing of e-waste in unauthorized locations on a considerably large scale. However, the academic research on the environmental consequences of informal recycling practices is limited. Soil and groundwater samples for five important and representative informal e-waste recycling processes and one related oil process were collected and analyzed to determine heavy metal-, PBDEs, PCBs, CBs, and PAHs concentrations. Contamination indices were used to assess and compare the effects of informal recycling processes, thereby providing a geochemical evaluation of soil conditions. As a result, the manual dismantling of CRT and ICT devices is the major source of heavy metal pollution. Furthermore, the burning of e-waste plastic for waste reduction purposes and the oil collection process substantially contribute to the input of organic pollutants. Regulatory measures for CRT and ICT recycling would result in an 85% reduction of heavy metals and the enforcement of a compulsory collection system for plastic and oil would eliminate 86% of the organic pollutants.

Odour emissions are a major environmental issue in wastewater treatment plants and are considered to be the main cause of disturbance noticed by the exposed population. Odour measurement is carried out using analytical or sensorial methods. Sensorial analysis, being assigned to the “human sensor”, is the cause of a considerable uncertainty. In this study a correlation between analytical and sensorial methods was investigated. A novel tool was used to both define odour indexes and characterise the odour sources and the volatile substances that cause annoyance in a wastewater treatment plant, with the aim to remove the subjective component in the measure of the odours and define the induced impact. The sources and the main chemical substances responsible for the olfactory annoyances were identified. Around 36 different substances were detected, with more than half being smell relevant components as well as responsible. Dimethyl disulphide was identified as key compound. Results highlight the applicability of highly correlation between analytical and sensorial methods in odour emission monitoring.

The European Commission and the German government are committed to the United Nations SDG target 12.3 of reducing food waste along production chains and halving it at retail and consumer levels by 2030. European member states are required to monitor national food waste levels and report annual progress to the European Commission from 2020 onward. In this regard, the main objective of our study is to provide food waste quantities for Germany by applying methods meeting the legal requirements for monitoring and reporting within Europe-wide harmonized methodology. Our results refer to 2015 and are based on the best available data, using a combination of official statistics, surveys, and literature. We found that approx. 11.9 ± 2.4 million tonnes (144 ± 28 kg/(cap·year)) of food waste were generated in Germany, while the reduction potentials varied throughout the different sectors. Even though the underlying data show uncertainties, the outcome of the study represents a starting point for the upcoming monitoring activities in Germany by uncovering data and knowledge gaps. To meet the political reduction targets, a national food waste strategy was launched in 2019 by the German Federal Ministry of Food and Agriculture, which is an important step toward cooperation and exchange between actors along the entire food chain, raising awareness, and improving data quality, monitoring, and implementation of prevention measures in practice.