Odour emissions from anaerobically co-digested biosolids: Identification of volatile organic and sulfur compounds.

Anaerobic co-digestion is emerging as an option for wastewater biosolids management. Variations in treatment parameters can impact odour emissions and, in turn, odour nuisance reduces community acceptance and alternatives for beneficial reuse of biosolids via land application. This study assessed odour emissions from digested sludge and biosolids resulting from the anaerobic co-digestion of wastewater sludge with beverage rejects (beer and cola) and food wastes.

Emission of fibres from textiles: A critical and systematic review of mechanisms of release during machine washing.

Research about health and environmental impacts of pollution caused by natural and plastic fibres is increasing, however, the role of textile characteristics in microfibre release during washing remains poorly understood. Given that machine washing is thought to be the main contributor to microfibre pollution, we systematically and critically reviewed previous publications looking at how textile features affect fibre emissions during washing. We examined the evidence related to findings from previous studies based on their research aims, ability to control variables that could confound results, use of procedural blanks and controls, and statistical methodologies.

Review of scientific research on air quality and environmental health risk and impact for PICTS.

Air quality (AQ) significantly impacts human health, influenced by both natural phenomena and human activities. In 2021, heightened awareness of AQ's health impacts prompted the revision of the World Health Organization (WHO) guidelines, advocating for stricter pollution standards. However, research on AQ has predominantly focused on high-income countries and densely populated cities, neglecting low- and middle-income countries, particularly Pacific Island Countries, Territories, and States (PICTS).

The use of gas chromatography combined with chemical and sensory analysis to evaluate nuisance odours in the air and water environment.

Varieties of gas chromatography (GC) combined with chemical detection (CD) and sensory analysis at the odour detection port (ODP) for the evaluation of environmental odorants has steadily increased in application and sophistication; this has given rise to a plethora of techniques that cater to specific tasks. With this diversity of approaches in mind, there is a need to assess the critical points at which these approaches differ, as well as likely risks and factors that may affect them. These critical points explained within this review include sample preparation, GC separation techniques (with associated co-elution risks), how the elute is separated between CD and sensory analysis, the type of CD, the type of sensory analysis (with particular attention paid to its factors and guidelines), integrative data techniques, as well as how that data may be used.

The role of microbial ecology in improving the performance of anaerobic digestion of sewage sludge.

The use of next-generation diagnostic tools to optimise the anaerobic digestion of municipal sewage sludge has the potential to increase renewable natural gas recovery, improve the reuse of biosolid fertilisers and help operators expand circular economies globally. This review aims to provide perspectives on the role of microbial ecology in improving digester performance in wastewater treatment plants, highlighting that a systems biology approach is fundamental for monitoring mesophilic anaerobic sewage sludge in continuously stirred reactor tanks. We further highlight the potential applications arising from investigations into sludge ecology.

Identifying robust and reliable volatile organic compounds in human sebum for biomarker discovery.

Sebum from sebaceous glands is a rich source of volatile organic compounds (VOCs) that can readily be sampled non-invasively from the surface of skin. The VOC profiles of sebum can then be used to obtain information regarding different medical conditions including diabetes and Parkinson's Disease. However, the effects of sampling approaches and environmental factors on sebum VOC profiles are not established and the confident attribution of VOCs to disease states needs to be free of extraneous influences such as sampling materials and preparatory conditions.

Management of biogenic taste and odour: From source water, through treatment processes and distribution systems, to consumers.

Biogenic taste and odour (T&O) have become a global concern for water utilities, due to the increasing frequency of algal blooms and other microbial events arising from the combined effects of climate change and eutrophication. Microbially-produced T&O compounds impact source waters, drinking water treatment plants, and drinking water distribution systems. It is important to manage across the entire biogenic T&O pathway to identify key risk factors and devise strategies that will safeguard the quality of drinking water in a changing world, since the presence of T&O impacts consumer confidence in drinking water safety.

Odour concentrations prediction based on odorants concentrations from biosolid emissions.

Biosolids storage areas are a significant contributor to wastewater treatment plant (WWTPs) odour emissions which can cause sensorial impact to surrounding communities. Most odour impact regulations are based on odour concentration (COD) measurements determined by dynamic olfactometry. Understanding the relationship between odorants concentrations and COD in the biosolids emission is important to identify how the measurement and monitoring can be conducted using analytical rather than sensorial techniques.

Measuring volatile emissions from biosolids: A critical review on sampling methods.

As a by-product of wastewater treatment, biosolids are a source of volatile emissions which can lead to community complaints due to odours and other pollution risks. Sampling methods play a significant role in collecting gas emissions from biosolids-related sources (i.e.

Performance of wet scrubbers to remove VOCs from rubber emissions.

Poor performance of wet scrubbers in rubber processing plants due to breakthrough of specific volatile organic compounds (VOCs) causes odour impact events. The performance of wet scrubbers in the rubber drying process to remove VOCs was investigated in order to determine the responsible odorants. VOC emissions originating at the inlet and outlet of wet scrubbers were quantified using gas chromatography-mass spectrometry/olfactometry (GC-MS/O).

Calibration methods for VSCs measured on AS-TD-GC-SCD.

Volatile sulfur compounds (VSCs) are key odorous compounds from emissions of various odour sources because they are odorous and generally have very low odour threshold values. Identification and quantification of them through air server-thermal desorber-gas chromatography-sulfur chemiluminescence detector (AS-TD-GC-SCD) become more and more popular, although VSCs can be determined by other detectors. To find a valid, practical and quick calibration method is also an important step in their analytical processes.

Identification of volatile sulfur odorants emitted from ageing wastewater biosolids.

Volatile sulfur compounds (VSCs) are important sources of unpleasant odours in biosolid emissions. However, the study of VSCs may be limited by complications in their gas phase measurements due to reactivity, transformations and varying reported odour detection thresholds. A range of methods were used to quantitatively analyse VSCs in wastewater biosolid emissions.

Occurrence and risk assessment of trace organic contaminants and metals in anaerobically co-digested sludge.

Anaerobic co-digestion of sludge increases biogas production and maintains anaerobic digestion stability. However, it is unclear whether the addition of co-substrates may increase the concentration of trace organic contaminants (TrOCs) and metals, limiting potential resource recovery opportunities when applied to agricultural land. This study explored the occurrence of 20 TrOCs and 18 metals in wastewater sludge anaerobically co-digested with beverage rejects (cola, beer and juice) and food wastes.

Modelling atmospheric emissions from wastewater treatment plants: Implications of land-to-water roughness change.

Atmospheric emissions from passive liquid surfaces, such as wastewater treatment plants (WWTP), are common sources of impacts to the environment and to the health of communities, due to odours, greenhouse gases and other air pollutants. Emission models have been broadly employed for assessing these emissions, with the wind friction velocity (u) being a key variable. The usual practice in the context of WWTP is to parametrise u based on reference wind speeds measured over the land, without considering the internal boundary layer (IBL) development due to the change in aerodynamic roughness as the wind blows from the land to the liquid surface, nor the stability of the wind flow.

Analysis of nitrous oxide emissions from aerobic granular sludge treating high saline municipal wastewater.

Conventional activated sludge (CAS)-based wastewater treatment processes have the potential to emit high concentrations of nitrous oxide (NO) during nitrification and denitrification, which can significantly impact the environmental performance and carbon footprint of wastewater treatment operations. While NO emissions from CAS have been extensively studied, there is little knowledge of NO emissions from aerobic granular sludge (AGS) which is now an increasingly popular secondary treatment alternative. The NO emissions performance of AGS needs to be investigated to ensure that the positive benefits of AGS, such as increased capacity and stable nutrient removal, are not offset by higher emissions.

Comparison of mass transfer parameters inside a USEPA flux hood for two VOCs.

Odorous emissions from area sources at wastewater treatment plants have become an environmental issue due to negative impacts on neighboring communities causing annoyance. Enclosure devices (such as dynamic flux chambers) have been used as direct methods to estimate area source emission rates from liquid-gas surfaces. Previously, model compounds have provided information about the internal mass transfer behavior of these sampling devices and the parameters estimated for certain model compounds that can be adapted for other compounds with similar liquid-gas partitioning properties.

Mortality risks due to long-term ambient sulphur dioxide exposure: large variability of relative risk in the literature.

Several studies have been published about the potential health effects due to long-term exposure to sulphur dioxide (SO) and the relative risks (RRs) for different causes of mortality. Broad differences in the RR values are found, however. In this study, we performed an analysis of these studies aiming finding potential explanations for the high variability of the RR reported.

Selection framework for the treatment of sewer network emissions.

Increasing urban growth and lifestyle expectations have led to an increase in public complaints against odours from sewer infrastructure. Gas phase odour abatement in sewer networks, particularly at sewer pumping stations, is most commonly achieved by using biofilters, biotrickling filters or activated carbon filters. When odour complaints are received, a typical response is to close vents, leading to biogenic corrosion in sewers, which increases operating costs.

Importance of 2,4,6-Trichloroanisole (TCA) as an odorant in the emissions from anaerobically stabilized dewatered biosolids.

Odours from stabilized biosolids after anaerobic digestion of wastewater sludge can cause local community impact. Apart from the well-known odorants such as sulfur compounds, contributions from other volatile organic compounds (VOCs) to nuisance odours is limited. The presence of compounds with low odour detection thresholds (ODTs) at low concentrations, can present challenges for analytical identification.

Investigation of non-community stakeholders regarding community engagement and environmental malodour.

Research into industry-community relationships have focused almost exclusively on the ways in which communities responds to actions from industries. This has led to a paucity of understanding with regards to how community engagement and malodour amelioration practices have been adopted by industry personnel, as well as the attitudes and beliefs of non-community stakeholders in general. In this study, a survey to water industry personnel was distributed to three Australian water utilities in South-Eastern Australia and a semi-structured interview process was carried out with plant managers at six wastewater treatment plants.

Diagnosing water treatment critical control points for cyanobacterial removal: Exploring benefits of combined microscopy, next-generation sequencing, and cell integrity methods.

A wide range of cyanobacterial species and their harmful metabolites are increasingly detected in water bodies worldwide, exacerbated by climate change and human activities. The resulting bloom conditions represent significant challenges to production of safe drinking water and cost effective water reuse, therefore their removal is a priority to ensure public safety. While current microscopic taxonomy identification methods provide valuable information about cell numbers during treatment, these methods are incapable of providing information about the fate of cells during treatment.

Quantification of VOCs and the development of odour wheels for rubber processing.

The impacts of rubber variations (clonal, seasonal, and pre-treatment) were investigated to assess changes in the composition of volatile organic compounds (VOCs) emitted during rubber processing. VOC emissions from 14 different rubber types were evaluated by headspace micro-chamber (μ-TEC) extraction coupled with gas chromatography-mass spectrometry (GC-MS). Headspace extracted at 120 °C, which is equivalent to the drying temperature during rubber processing, revealed a significant number of odorants in terms of concentrations as well as odorant type.

Use of inorganic and organic markers associated with their directionality for the apportionment of highly correlated sources of particulate matter.

Particulate matter source identification using receptor models is one of the tools applied in air quality management. These models have limitations such as the collinearity effects, hindering their application and interpretation. Positive Matrix Factorization (PMF) models use chemical markers for the definition of likely sources, leaving to users the factors interpretation.