Occurrence of organic microcontaminants in the wastewater treatment process. A mini review

A wastewater treatment plant may receive various types of wastewater namely, urban, industrial, agricultural, washout from the streets, wet or/and dry atmospheric deposition. As such, scientists have detected in wastewaters all major categories of pollutants like persistent organic pollutants (POPs), polycyclic aromatic hydrocarbons (PAHs) and pesticides, but also substances that are widely used as pharmaceuticals and cosmetics, classified as "PPCPs" (pharmaceuticals and personal care products). Finally, the latest categories of compounds to be looked upon in these types of matrices are illicit drugs (drugs of abuse, like cocaine, etc.) and doping substances. This review article summarises major categories of organic microcontaminants that have been detected in wastewaters and studies their fate during the wastewater treatment process. Occurrence of these compounds in the influents and effluents are reported, as well as percents of removal, mass balances and phase distributions

Occurrence of linear and cyclic volatile methyl siloxanes in indoor air samples (UK and Italy) and their isotopic characterization

The occurrence of linear- and cyclic-volatile methyl siloxanes (lVMSs and cVMSs, respectively) in various indoor environments, occupational and domestic, in Italy and in the United Kingdom was studied. The results show that the cVMSs are the most abundant, detected in average concentrations that in some cases were as high as 170 μg m−3. Our study highlights the differences that can be observed between various indoor environments (e.g. domestic like bathrooms, bedrooms, or occupational) and between two countries. In most cases, the concentrations found in the UK are higher than in the respective indoor environments in Italy. The assessment of exposure to these two countries for adults and children revealed significant differences both not only in the levels of exposure, but also in the patterns. In Italy, the biggest part of the exposure to VMSs takes place domestically, whereas in the UK, it is observed for occupational environments.Additionally, the compound specific isotopic analysis was employed as a source identification technique. The results are promising mainly for D5 that occurs in higher concentrations, but not for the less abundant lVMSs and cVMSs. Keywords: Indoor air, Siloxanes, D4, D5, Exposure assessment, CSI

Removal of Arsenic (III) from water with a combination of Graphene Oxide (GO) and Granular Ferric Hydroxide (GFH) at the optimum molecular ratio

The occurrence of arsenic in water is a global problem for public health. Several removal technologies have been developed for arsenic removal from water, and adsorption onto iron oxyhydroxides is the most widely used technique. Granular ferric hydroxide (GFH) has been used mainly for As(V) removal, but it has the disadvantage that it can create a problem with the residual concentration of iron in the water. Moreover, graphene oxide (GO), which contains a large amount of reactive oxygen, exhibits high adsorbing capacity. In this study, the combined use of GO and GFH as adsorbent materials in different molar ratios was investigated in order to achieve the maximum As(III) removal from aqueous solutions. The effect of the adsorbent’s dosage, pH value, contact time, initial As(III), and different molar ratios of GO/GFH was examined. As depicted, the presence of GFH enhances the use of GO. In particular, the molar ratio of GO/GFH 2:1 (i.e., 0.2 g/L GO and 0.1 g/L GFH) is chosen as optimal at pH value 7.0 ± 0.1, while the removal percentage increased from 10% (absence of GFH) to 90% with the simultaneous addition of GFH. Freundlich isotherm and pseudo-second-order kinetic models described the experimental data adequately and the highest adsorption capacity that was achieved was 22.62 µg/g

Atmospheric Occurrence and Gas-Particle Partitioning of PBDEs in an Industrialised and Urban Area of Florence, Italy

Air samples were collected both at an urban and an industrial area of Florence (Italy) in order to evaluate the occurrence, profiles, seasonal variation and gas/particle partitioning of polybrominated diphenyl ethers (PBDEs). The mean total (gas + particle phase) PBDE concentrations were 42.8 ± 7.8 and 89.0 ± 21.1 pg/m3 in the urban and industrial sites, respectively. In all samples, BDE-209 was the most abundant congener, followed by BDE-47 and BDE-153 in the industrial site, and by BDE-99 in the urban site. The Σ6PBDE (sum of BDE-28, -47, -99, -100, 153, -154) concentrations in the urban (12.1–27.9 pg/m3) and industrialised (21.4–44.3 pg/m3) sites were comparable to, or slightly lower than measured at other sites. The partition coefficient of PBDEs between the gas and particle phases (Kp) was well correlated with the subcooled liquid vapor pressure (P°L) for all samples. The measured particulate sorption of PBDEs was compared to the predictions from Junge-Pankow (J/P) model and KOA absorption model. While the Junge-Pankow model tends to overestimate the particulate sorption, the KOA based model seemed to fit the PBDE data

Extraction and purification of phosphorus from the ashes of incinerated biological sewage sludge

Phosphorus depletion represents a significant problem. Ash of incinerated biological sewage sludge (BSS) contains P, but the presence of heavy metals (e.g., Fe and Al) is the main issue. Based on chemical characterization by SEM-EDS, ED-XRF and ICP-OES techniques, the characteristics and P content of bottom ash (BA) and fly ash (FA) of incinerated BSS were very similar. On BA, P extraction carried out in counter-current with an S:L ratio of 1:10 and H2SO4 0.5 M led to better extraction yields than those of a similar test with H2SO4 1 M and an S:L ratio of 1:5 (93% vs. 86%). Comparing yields with H2SO4 0.5 M (S:L ratio of 1:10), the counter-current method gave better results than those of the crossflow method (93% vs. 83.9%), also improving the performance obtained with HCl in crossflow (93% vs. 89.3%). The results suggest that the purification of the acid extract from heavy metals with pH variation was impractical due to metal precipitation as phosphates. Extraction with H2SO4 and subsequent treatment with isoamyl alcohol represented the best option to extract and purify P, leading to 81% extraction yields of P with low amounts of metals

Applications of Up-flow Anaerobic Sludge Blanket (UASB) and characteristics of its microbial community: a review of bibliometric trend and recent findings

Interest of research on up-flow anaerobic sludge blanket (UASB) reactors is growing. The meta-analysis of bibliometric data highlighted the growing interest in four diverse topics: (i) energy recovery production; (ii) combination with other treatments; (iii) the study of processes for the removal of specific pollutants and, (iv) characterization of microbial community and granular sludge composition. In particular, the papers pub-lished in the first 6 months of 2021 on this process have been selected and critically re-viewed to highlight and discuss the results, the gaps in the literature and possible ideas for future research. Although the state of research on UASB is to be considered advanced, there are still several points that will be developed in future research such as the consoli-dation of the results obtained on a semi-industrial or real scale, the use of real matrices in-stead of synthetic ones and a more in-depth study of the effect of substances such as anti-biotics on the microbiota and microbiome of UASB granular biomass. To date, few, and conflicting data about environmental footprint of UASB are available and therefore other studies on this topic are strongly suggested

The TOMPs ambient air monitoring network:continuous data on UK air quality for over 20 years

Long-term air monitoring datasets are needed for persistent organic pollutants (POPs) to assess the effectiveness of source abatement measures and the factors controlling ambient levels. The Toxic Organic Micro Pollutants (TOMPs) Network, which has operated since 1991, collects ambient air samples at six sites across England and Scotland, using high-volume active air samplers. The network provides long-term ambient air trend data for a range of POPs at both urban and rural locations. Data from the network provides the UK Government, regulators and researchers with valuable information on emission/source controls and on the effectiveness of international chemicals regulation such as the Stockholm Convention and UN/ECE Protocol on POPs. The target chemicals of TOMPs have been polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and, since 2010, polybrominated diphenyl ethers (PBDEs). The continuous monitoring of these compounds demonstrates the constant decline in UK air concentrations over the last two decades, with average clearance rates for PCDD/Fs in urban locations of 5.1 years and for PCBs across all sites 6.6 years. No significant declines in rural locations for PCDD/Fs have been observed. There is a strong observable link between the declining ambient air concentrations and the emission reductions estimated in the annually produced National Atmospheric Emission Inventory (NAEI) dataset. These findings clearly demonstrate the unique strengths of long-term consistent datasets for the evaluation of the success of chemical regulation and control

A mini review of recent findings in Cellulose-, Polymer- and Graphene-based membranes for Fluoride removal from drinking water

Effective fluoride removal from water is a persistent global concern both for drinking water and wastewater treatment. According to World Health Organization (WHO) standards the maximum contaminant level in drinking water cannot be higher than 1.5 mg F 12 L-1 since affects the skeletal and nervous systems of humans. Various technologies have been developed to decrease fluoride concentration from waters, such as adsorption, coagulation, precipitation and membrane separa-tion. Membrane technology found to be a very effective technology, significantly reducing fluo-ride to desired standards levels; however, has received less attention than other technologies because it is apparent as a costly process. This review aims to discuss the recent studies using modified membranes for fluoride removal. Emphasis is given on cellulose, polymer and gra-phene based membranes and is further discussing the modification of membranes with several metals that have been developed in the last years. It was observed that the main focus of the to-tal publications, has been on the use of polymer based membranes. Most of the membranes ap-plied for defluoridation exhibit greater efficiency at pH values close to that of drinking water (i.e., 6\u20138).and maximum treatment capacity was obtained with the use of a cellulose modified membrane Fe-Al-Mn@chitosan with a permeate flux of 2000 L m-2 h-1, following the carbon based amyloid fibril nano-ZrO2 composites (CAF-Zr) 1750 L m-2. A technical-economic comparison study of NF and RO is also referred, concluding that NF membrane is slightly less expensive

Geochemistry of As-, F- and B-bearing waters in and around San Antonio de los Cobres, Argentina, and implications for drinking and irrigation water quality

Spring, stream and tap waters from in and around San Antonio de los Cobres, Salta, Argentina, were sampled to characterize their geochemical signatures, and to determine whether they pose a threat to human health and crops. The spring waters are typical of geothermal areas world-wide, in that they are Na-Cl waters with high concentrations of Astot, As(III), Li, B, HCO3, F and SiO2 (up to 9.49, 8.92, 13.1, 56.6, 1250, 7.30 and 57.2 mg L-1, respectively), and result from mixing of deep Na-Cl brines and meteoric HCO3-rich waters. Springs close to the town of San Antonio have higher concentrations of all elements, and are generally cooler, than springs in the Baños de Agua Caliente. Spring water chemistry is a result of mixing of deep Na-Cl brines and meteoric HCO3 waters. Stream waters are also Na-Cl type, and receive large inputs of all elements from the springs near San Antonio, but concentrations decrease downstream through the town of San Antonio due to mineral precipitation. The spring that is used as a drinking water source, and other springs in the area, have As, F and B concentrations in excess of WHO and Argentinian drinking water guidelines. Evaluation of the waters for irrigation purposes suggests that their high salinities and B concentrations may adversely affect crops. The waters may be improved for drinking and irrigation by dilution with cleaner meteoric waters, mineral precipitation or by use of commercial filters. Such recommendations could also be followed by other settlements that draw drinking and irrigation waters from geothermal sources