Untreated Urban Wastewater Research Articles

Resilience of anodic biofilm in microbial fuel cell biosensor for BOD monitoring of urban wastewater

Efficient wastewater treatment monitoring is vital for addressing water scarcity. Microbial fuel cells (MFCs) have emerged as real-time biosensors for biochemical oxygen demand (BOD) in urban wastewater. Discrepancies in signal generation may arise due to changes in the composition and metabolism of mixed-culture electroactive biofilms stemming from different wastewater compositions. In this study, 3D-printed MFC-based biosensors were employed to assess the BOD of sterile complex artificial wastewater and untreated urban wastewater. Alterations in the microbial composition of the anode were evaluated using 16S rRNA sequencing and metagenomics analysis. Results show that MFC-based biosensors can be effectively recalibrated for diverse types of wastewater, maintaining consistent sensitivity (0.64 ± 0.10 mA L mg−1 m−2 with synthetic wastewater and 0.78 ± 0.13 mA L mg−1 m−2 with urban wastewater) and limit of detection (49 ± 8 mg L−1 for synthetic wastewater and 44 ± 7 mg L−1 for urban wastewater). Crucially, pre-sterilization, conductivity adjustments, and nitrogen purging of wastewater are not required before its introduction into the biosensor. However, the presence of native aerobic microorganisms in the wastewater might affect the current output. Metagenomics and taxonomic analyses revealed that the alterations in biofilm composition are predominantly in response to the varied chemical and microbiological compositions of different substrates. Despite variations in anodic biofilm composition, the MFC-based biosensor maintains a relative error comparable to the standard BOD test. This highlights the resilience and flexibility of the biosensor when directly used with a variety of wastewater types before full biofilm adjustment.

Quantitative microbial risk assessment of gastrointestinal illness due to recreational exposure to E. coli and enterococci on the southern coasts of the Caspian Sea

BackgroundGastrointestinal illness refers to a broad range of diseases that affect the digestive system, including infections caused by bacteria, viruses, and parasites. Quantitative Microbial Risk Assessment (QMRA) is a powerful tool used to evaluate the risks associated with microbial pathogens in various environments. The main objective of this study was to conduct a quantitative assessment of gastrointestinal illnesses that occur as a result of exposure to E. coli and enterococci during recreational activities on the southern coasts of the Caspian Sea. MethodsSamples were collected from the recreational beaches along the border line of the Caspian Sea. The samples were analyzed for the presence and enumeration of E. coli and enterococci using the microplate method and membrane filtration techniques. Then, the annual and daily infection risks were computed using the Monte Carlo simulation approach. ResultsThe results revealed that the risk of daily and annual infections on the coasts of Babolsar was higher than that on the coasts of Sari. Also, in the recreational waters of these beaches, the risk of infection by enterococci was higher than that posed by E. coli. In Babolsar, the average annual infection risk caused by E. coli and enterococci was 0.365 and 1 for children and 0.181 and 0.986 for adults. Also, in Sari, the average annual infection risk caused by E. coli and enterococci was 0.060 and 0.908 for children and 0.027 and 0.815 for adults. In addition, children were more likely than adults to become infected. ConclusionIn light of the study's findings, due to the entry of untreated urban wastewater into the southern part of the Caspian Sea (northern Iran) and the high risk of infectious diseases for children, more control and health measures are necessary for children's swimming.

Metal contamination, their ecological risk, and relationship with other variables in surface sediments of urban rivers in a big city in Asia: case study of Hanoi, Vietnam.

Urban rivers are significantly impacted by anthropogenic pressure. This study presents the updated assessment of the concentrations of 11 metals and other variables (pH, total organic carbon (TOC) and nutrients (total nitrogen, total phosphorus, and total silica)) in the sediments of four urban rivers in inner Hanoi city, Vietnam, during the period 2020-2022. The mean concentrations of Fe, Zn, As, and Cr were higher than the permissible values of the Vietnam National technical regulation on the surface sediment quality. Moreover, Zn and Cr were at the severe effect level of the US EPA guidelines for sediment quality. The calculation of pollution indices (Igeo and EF) demonstrated that Mn, Ni, and Fe were from natural sources whereas other metals were from both anthropogenic and natural sources. The ecological risk index revealed that metals in Hanoi riverine sediments were classified at considerable ecological risk. High values of metals, TOC, and nutrients in the sediments of these urban rivers mostly originate from the accumulation of untreated urban wastewater that is enhanced by low river discharge. Our results may provide scientific base for better management decisions to ensure environmental protection and sustainable development of Hanoi city.

ABACO-2: a comprehensive model for microalgae-bacteria consortia validated outdoor at pilot-scale

Modelling microalgae-bacteria in wastewater treatment systems has gained significant attention in the last few years. In this study, we present an enhanced version of the ABACO model, named ABACO-2, which demonstrates improved accuracy through validation in outdoor pilot-scale systems. ABACO-2 enables the comprehensive characterization of microalgae-bacteria consortia dynamics, allowing to predict the biomass concentration (microalgae, heterotrophic bacteria, and nitrifying bacteria) and nutrient evolution. The updated version of the model incorporates new equations for nutrient coefficient yields, oxygen mass balance, and microorganism cellular decay, while significantly reducing the number of calibrated parameters, simplifying the parameter identification. Calibration and validation were performed using data from a 80 m2 raceway reactor operated in a semicontinuous mode over an extensive period (May to November, total of 206 days) at a fixed dilution rate of 0.2 day-1 (corresponding to 5 days of hydraulic retention time), where untreated urban wastewater was used as culture medium. ABACO-2 exhibited robustness, accurately forecasting biomass production, population dynamics, nutrient recovery, and prevailing culture conditions across a wide range of environmental and water composition conditions. Mathematical models are essential instruments for the industrial development and optimization of microalgae-related wastewater treatment processes, thereby contributing to the sustainability of the wastewater treatment industry.

AIEgen orthopalladated hybrid polymers for efficient inactivation of the total coliforms in urban wastewater

Monitorable AIE polymers with a bioactive pattern are employed in advanced biomedical applications such as functional coatings, theranostic probes, and implants. After the global COVID-19 pandemic, interest in developing surfaces with superior antimicrobial, antiproliferative, and antiviral activities dramatically increased. Many formulations for biocide surfaces are based on hybrid organic/inorganic materials. Palladium (II) complexes display relevant activity against common bacteria, even higher when compared to their uncoordinated ligands. This article reports the design and synthesis of two series of orthopalladated polymers obtained by grafting a cyclopalladated fragment on two different O, N chelating Schiff base polymers. Different grafting percentages were examined and compared for each organic polymer. The fluorescence emission in the solid state was explored on organic matrixes and grafted polymers. DFT analysis provided a rationale for the role of the coordination core. The antibacterial response of the two series of hybrid polymers was tested against the total coliform group of untreated urban wastewater, revealing excellent inactivation ability.

Effects of intensive agriculture and urbanization on water quality and pesticide risks in freshwater ecosystems of the Ecuadorian Amazon

The Ecuadorian Amazon has experienced a significant land use change due to the demographic increase and the expansion of the agricultural frontier. Such changes in land use have been associated to water pollution problems, including the emission of untreated urban wastewater and pesticides. Here we provide the first report on the influence of urbanization and intensive agriculture expansion on water quality parameters, pesticide contamination and the ecological status of Amazonian freshwater ecosystems of Ecuador. We monitored 19 water quality parameters, 27 pesticides, and the macroinvertebrate community in 40 sampling locations of the Napo River basin (northern Ecuador), including a nature conservation reserve and sites in areas influenced by African palm oil production, corn production and urbanization. The ecological risks of pesticides were assessed using a probabilistic approach based on species sensitivity distributions. The results of our study show that urban areas and areas dominated by African palm oil production have a significant influence on water quality parameters, affecting macroinvertebrate communities and biomonitoring indices. Pesticide residues were detected in all sampling sites, with carbendazim, azoxystrobin, diazinon, propiconazole and imidacloprid showing the largest prevalence (>80% of the samples). We found a significant effect of land use on water pesticide contamination, with residues of organophosphate insecticides correlating with African palm oil production and some fungicides with urban areas. The pesticide risk assessment indicated organophosphate insecticides (ethion, chlorpyrifos, azinphos-methyl, profenofos and prothiophos) and imidacloprid as the compounds posing the largest ecotoxicological hazard, with pesticide mixtures potentially affecting up to 26–29% of aquatic species. Ecological risks of organophosphate insecticides were more likely to occur in rivers surrounded by African palm oil plantations, while imidacloprid risks were identified in corn crop areas as well as in natural areas. Future investigations are needed to clarify the sources of imidacloprid contamination and to assess its effects for Amazonian freshwater ecosystems.

ASSESSMENT OF URBAN WASTEWATER POLLUTIONDISCHARGED BY THE MOROCCAN CITY OF KENITRA AT THESEBOU RIVER ESTUARY

The dangerous chemical contamination of the Sebou River Estuary by the untreated urban wastewater from the city of Kenitra has been the subject of an extensive and comprehensive characterization through the study of the physico-chemical qualities of effluent samples from eight different municipal wastewater collectors (A, B, C, D, E, F, G and H) using standard methods. The evaluated physico-chemical parameters include: flow rate, pH, temperature (T °), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), suspended matter (SM) and electrical conductivity (EC). The characterization of the examined parameters displayed a moderately neutral pH level in the domestic wastewater collectors (B to H), nonetheless, collector (A) showcased an exceptionally alkaline pH that arrays from 8.1 to 9.6, which in turn impacts the electrical conductivity and temperature, to the point of occasionally reaching up to 30.3 °C in the collectorin question. Pertaining to the collected (COD) and (BOD5) results, their values significantly exceeded the Moroccan standards, especially in collectors A, G and F, exhibiting thus low biodegradability with a COD / BOD5 ratio exceeding 3. The characterization of municipal wastewater and the measurement of its flow made the estimation of the pollution quantity discharged at the level of the Sebou river estuary achievable, these data will subsequently be used in favor of modeling and monitoring the fate of pollution in the receiving environment.

High MICs for antifungal agents in yeasts from an anthropized lagoon in South America

The lagoons are fragile ecosystems used by several species as a refuge and breeding area, and it is also a place where certain communities practice fishing activity. With increasing urbanization around this ecosystem, pesticides used in agriculture and untreated urban wastewater are drained into the river basin, resulting in the dispersion of organic matter and antifungals used by the population and farmers. These may favor the selection of resistant pathogens directly into the environment, a concern since several fungi have emerged as pathogens in the last decades. In this study, we investigated the presence in an impacted lagoon by potentially resistant yeasts to antifungal agents. We evaluated their capacity for producing extracellular enzymes that could act as virulence factors. Water samples from the Tramandaí lagoon were analyzed for the presence of pesticides using the SPE-LC-ESI-MS/MS. Tricyclazole, carbendazim, azoxystrobin, thiabendazole, and tebuconazole were found. Twenty-eight yeast species were isolated, including the multidrug-resistant Candida haemulonii, and species with high minimal inhibitory concentrations (MICs) for clinical antifungal agents. Around 93% of the isolates had MIC values above the resistance breakpoints established for Candida species for at least two antifungal agents. And 27% had high MICs values for fluconazole, terbinafine, amphotericin B, and caspofungin. Tebuconazole MICs values were highly associated with MICs for fluconazole, terbinafine, and amphotericin B, and significant correlations between high MICs for antifungal agents and enzyme production were found. The results indicated that the lagoon is a reservoir of resistance genes and a potential source for fungal infection, highlighting the importance of the One Health approach and the integrated vision of the ecosystem when managing these environments.

Sources and Distribution of Organic Matter in Coastal Area of Muang Chonburi District, Eastern Thailand: Using Carbon and Nitrogen Stable Isotopes

The sources and spatial distribution of organic matter were investigated in the nearshore area receiving untreated urban wastewater and offshore areas containing bivalve mariculture in Muang Chonburi District. Content, elemental, carbon, and nitrogen isotopic analyses in particulate organic matter (POM) and surface sediments were performed. We found particulate organic carbon (POC), δ13C, and δ15N of POM ranging from 435.0-5,247.7 µg/L, -27.7 to -22.0 ‰, and 1.7-8.6 ‰, respectively, whereas total organic carbon (TOC), total nitrogen (TN), δ13C and δ15N in sediment were 3.5-76.9 µg/g, 0.8-8.3 µg/g, -25.7 to -22.9 ‰ and 2.6-6.0 ‰, respectively. These values show significant differences between nearshore and offshore sampling stations wherein accumulation of organic matter was high in the nearshore and decreased with greater distance offshore, with some retained in the bivalve farming area. The results from a mixing model indicated that organic matter in POM and sediment were initially derived from anthropogenic organic matter. In contrast to the offshore water which had organic matter derived from marine organic matter. This study highlights the distribution of anthropogenic organic waste released to coastal waters with plenty of bivalve farms such as green mussels and oysters. The results can be used to advise national strategies regarding bivalve aquaculture zoning and seafood safety policies going forward.

The bacterial community composition and its environmental drivers in the rivers around eutrophic Chaohu Lake, China

BackgroundBacterial community play a key role in environmental and ecological processes in river ecosystems. Rivers are used as receiving body for treated and untreated urban wastewaters that brings high loads of sewage and excrement bacteria. However, little is known about the bacterial community structure and functional files in the rivers around the eutrophic Chaohu Lake, the fifth largest freshwater lake in China, has been subjected to severe eutrophication and cyanobacterial blooms over the past few decades. Therefore, understanding the taxonomic and functional compositions of bacterial communities in the river will contribute to understanding aquatic microbial ecology. The main aims were to (1) examine the structure of bacterial communities and functional profiles in this system; (2) find the environmental factors of bacterial community variations.ResultsWe studied 88 sites at rivers in the Chaohu Lake basin, and determined bacterial communities using Illumina Miseq sequencing of the 16 S rRNA gene, and predicted functional profiles using PICRUSt2. A total of 3,390,497 bacterial 16 S rRNA gene sequences were obtained, representing 17 phyla, and 424 genera; The dominant phyla present in all samples were Bacteroidetes (1.4-82.50 %), followed by Proteobacteria (12.6–97.30 %), Actinobacteria (0.1–17.20 %). Flavobacterium was the most numerous genera, and accounted for 0.12–80.34 % of assigned 16 S reads, followed by Acinetobacter (0.33–49.28 %). Other dominant bacterial genera including Massilia (0.06–25.40 %), Psychrobacter (0-36.23 %), Chryseobacterium (0.01–22.86 %), Brevundimonas (0.01–12.82 %), Pseudomonas (0-59.73 %), Duganella (0.08–23.37 %), Unidentified Micrococcaceae (0-8.49 %). The functional profiles of the bacterial populations indicated an relation with many human diseases, including infectious diseases. Overall results, using the β diversity measures, coupled with heatmap and RDA showed that there were spatial variations in the bacterial community composition at river sites, and Chemical oxygen demand (CODMn) and (NH4+ )were the dominant environmental drivers affecting the bacterial community variance.ConclusionsThe high proportion of the opportunistic pathogens (Acinetobacter, Massilia, Brevundimonas) indicated that the discharge of sewage without adequate treatment into the rivers around Chaohu Lake. We propose that these bacteria could be more effective bioindicators for long-term sewage monitoring in eutrophic lakes.

Plant debris are hotbeds for pathogenic bacteria on recreational sandy beaches

On recreational sandy beaches, there are guidelines for the management of bacterial pollution in coastal waters regarding untreated sewage, urban wastewater, and industrial wastewater. However, terrestrial plant debris on coastal beaches can be abundant especially after floods and whilst it has rarely been considered a concern, the bacterial population associated with this type of pollution from the viewpoint of public health has not been adequately assessed. In this study, microbes associated with plant debris drifting onto Kizaki Beach in Japan were monitored for 8 months throughout the rainy season, summer, typhoon season, and winter. Here we show that faecal-indicator bacteria in the plant debris and sand under the debris were significantly higher than the number of faecal bacteria in the sand after a 2015 typhoon. When we focused on specific pathogenic bacteria, Brevundimonas vesicularis and Pseudomonas alcaligenes were commonly detected only in the plant debris and sand under the debris during the survey period. The prompt removal of plant debris would therefore help create safer beaches.

Floating treatment wetland for nutrient removal and acute ecotoxicity improvement of untreated urban wastewater

Wastewater treatments are often expensive, and the resulting effluent can still harm the environment. Floating treatment wetland is an alternative low-cost eco-technology in which a hydroponic root network remediates polluted waters. This system has been broadly studied as a secondary treatment to remove nutrients and pollutants, but its application to improve raw wastewater quality is still incipient. Moreover, few studies have assessed acute ecotoxicity toward fish after treatment. Thus, this study aimed to evaluate the efficiency of a mesocosm floating treatment wetland to improve the raw wastewater quality from a university campus in South Brazil. Efficiency was assessed based on the improvement of physicochemical parameters (conductivity, pH, turbidity, color), nutrients (nitrogen and phosphorus), and heavy metals (zinc, chromium, copper, lead, and cadmium); Typha domingensis adaptability; and acute fish ecotoxicity reduction after wastewater treatment. Influent was treated with macrophytes tanks and their respective controls. T test was used to compare influent versus effluent samples, and macrophytes tanks versus controls. A Principal Component Analysis identified the main explanatory variables on the system, and a Two-way Cluster Analysis grouped samples before and after treatment. The results show floating mats efficiency in reducing most parameters compared to the influent, except phosphorus and zinc. Control tanks were also effective in improving wastewater quality due to microalgae and duckweed proliferation. In conclusion, floating treatment wetlands with Typha domingensis have the potential to treat raw wastewater. Further nitrogen removal in wastewater might improve acute ecotoxicity toward fish.

Carbon Nanomaterials: Application and Prospects of Urban and Industrial Wastewater Pollution Treatment Based on Abrasion and Corrosion Resistance.

Environmental pollution as a result of urban and industrial wastewater has become an increasingly prominent issue. Rivers, lakes, and oceans that have become eutrophicated or polluted by suspended solids and hazardous substances in wastewater have endangered the environment. A root cause of this is the discharge of untreated urban and industrial wastewater into the ecosystem. As a solution to the pollution, wastewater treatment facilities have seen increasingly rapid development. Sewage pumps are designed to transport urban and industrial wastewater containing solid particles or hazardous substances to water treatment centers for purification and treatment. Sewage pumps are of great importance in the entire wastewater treatment system. Sewage in the environment where sewage pumps work usually contains sands, suspended particles, and plenty of saline ions. Flow passage components and sealing elements of the pump become vulnerable to abrasion and chemical corrosion, which further challenges operational stability of the pump. Research has remained focused on how to improve reliability of sewage pumps under severe conditions. Because of advances in materials science, the application of an increasing number of new materials has been witnessed, such as carbon-based composite materials and carbon nanomaterials, thanks to their fine self-lubrication performance, heat resistance, thermal and electrical conductivity, chemical stability, heat and seismic resistance, as well as plasticity. These properties contribute to enormous potential that new carbon-based composite materials and carbon nanomaterials have to offer in terms of corrosion resistance. This paper outlines application scenarios, research progress, and the prospect of new materials in sewage pumps.

Algal blooms in a freshwater reservoir – A network community detection analysis of potential forcing parameters

Nutrient leakage due to modern agriculture and disposal of untreated urban wastewater results in the eutrophication of freshwater lakes and reservoirs, with elevated levels of cyanobacteria algal blooms often resulting in toxic conditions for animals and humans. A unique dataset of 22 coincident nutrient, phytoplankton, meteorological, and reservoir condition variables were recorded or calculated monthly for Hoover Reservoir near Columbus, Ohio, from February 1999 to December 2005. Network science was used in this study to visualize and differentiate selected nutrient and phytoplankton seasonality in Hoover Reservoir. Nutrient and phytoplankton concentrations in Hoover Reservoir respond independently to a number of external and internal environmental variables, but are also biochemically interdependent within the reservoir ecosystem. A number of forcing parameters can significantly alter seasonal phytoplankton growth and succession patterns. Chief among these are variability in the daily, seasonal, and/or yearly patterns and intensities of precipitation and the resultant surface runoff; duration and intensity of solar radiation; air and resultant water temperatures; and agricultural practices. The phytoplankton population in Hoover Reservoir is ecologically driven, with algal succession and nutrient levels constraining population concentrations. Complemented by selected statistical analyses, this limited network community detection study provides the hydrologist/ecologist with a dynamic and quantitative visualization of the complex hydrometeorological variable and biogeochemical process forcing parameters present in reservoirs and lakes.

Assessment of nutrient enrichment and heavy metal pollution of headwater streams of Bulawayo, Zimbabwe

The continuing degradation of riverine ecosystems by the discharge of poorly treated and untreated urban-wastewater (together referred to as partly treated urban-wastewater in this study) is a major problem in developing countries. This study assessed water and sediment quality of headwater streams radiating from the Bulawayo area including Umguza and Khami Rivers that drain wastewater from the City. Seventeen study sites were a priori selected from different land use types: City sites (5 sites), downstream communal sites (4), upstream communal sites (3) and for reference five sites were selected upstream of the City within the buffer zones of protected areas. Water and sediment samples were collected during the hot-wet, cold-dry and hot-dry seasons from these site categories and were analysed for selected physicochemical water parameters and heavy metals. The City sites were the most degraded as indicated by significantly highest levels of dissolved oxygen deficiency, embeddedness by particulates, turbidity, conductivity, total dissolved solids (TDS), salinity, total nitrogen (TN) and total phosphorus (TP) and chemical oxygen demand (COD) (ANOVA, p < 0.05). The City sites were also salinised. Principal component analysis (PCA) revealed that urban-wastewater was the major factor explaining the dissimilarity of the studied site clusters and the results also suggested that the sources of heavy metals in the study area were diffuse. Degradation of studied sites by urban-wastewater signifies negative health risks to biodiversity and humans particularly the downstream rural communities. Therefore, priority must be on interventions to ensure improvement of the quality of urban-wastewater discharged from City of Bulawayo to the environment.

Occurrence and assessment of environmental risks of endocrine disrupting compounds in drinking, surface and wastewaters in Serbia

The present study is the first comprehensive monitoring of 13 selected endocrine disrupting compounds (EDCs) in untreated urban and industrial wastewater in Serbia to assess their impact on the Danube River basin and associated freshwaters used as sources for drinking water production in the area. Results showed that natural and synthetic estrogens were present in surface and wastewater at concentrations ranging from 0.1 to 64.8 ng L−1. Nevertheless, they were not detected in drinking water. For alkylphenols concentrations ranged from 1.1 to 78.3 ng L−1 in wastewater and from 0.1 to 37.2 ng L−1 in surface water, while in drinking water concentrations varied from 0.4 to 7.9 ng L−1. Bisphenol A (BPA) was the most abundant compound in all water types, with frequencies of detection ranging from 57% in drinking water, to 70% in surface and 84% in wastewater. Potential environmental risks were characterized by calculating the risk quotients (RQs) and the estrogenic activity of EDCs in waste, surface and drinking water samples, as an indicator of their potential detrimental effects. RQ values of estrone (E1) and estradiol (E2) were the highest, exceeding the threshold value of 1 in 60% of wastewater samples, while in surface water E1 displayed potential risks in only two samples. Total estrogenic activity (EEQt) surpassed the threshold of 1 ng E2 L−1 in about 67% of wastewater samples, and in 3 surface water samples. In drinking water, EEQt was below 1 ng L−1 in all samples.

A major release of urban untreated wastewaters in the St. Lawrence River (Quebec, Canada) altered growth, reproduction, and redox status in experimentally exposed Daphnia magna

In 2015, five billion liters of untreated urban wastewater (UWW) were released into the St. Lawrence River (Quebec, Canada) over the course of four days in order to repair the Montreal's sewer interceptor network related to the city's primary wastewater treatment plant. The UWW discharge originated mainly from household, industrial, and hospital sources. The objective of this study was to investigate the toxicological effects of this unprecedented punctual UWW release on aquatic invertebrates to gather information that could help understand the potential impacts to the receiving environment of overflow episodes occurring during heavy rain events. Water samples were collected at four impacted and non-impacted sites during and four weeks after the release. The freshwater crustacean Daphnia magna were experimentally exposed to surface water collected from UWW-impacted sites for 13 days and analyzed for life-history endpoints and suitable biomarkers related to oxidative stress (i.e., catalase, superoxide dismutase, lipid peroxidation, and glutathione-s-transferase) and reproduction (chitinase). Results indicated that D. magna growth and reproduction were significantly increased by exposure to UWWs. These effects were correlated with an increase in chitinase activity, which is primarily controlled by reproductive hormones and involved in growth, suggesting potential impacts on these processes. Results also indicated that some UWW samples might have caused oxidative stress during the release but that it was overcome by antioxidant defenses and did not lead to cellular damage. Overall, current results contribute to a better understanding of the biological impacts of UWW to aquatic invertebrates for a better stormwater management.

Investigating microbial indicators of anthropogenic marine pollution by 16S and 18S High-Throughput Sequencing (HTS) library analysis.

High-Throughput Sequencing technologies are providing unprecedented inventories of microbial communities in aquatic samples, offering an invaluable tool to estimate the impact of anthropogenic pressure on marine communities. In this case study, the Mediterranean touristic site of Aci Castello (Italy) was investigated by High-Throughput Sequencing of 16S and 18S rRNA genes. The sampling area falls within a Marine Protected Area and, notwithstanding, features an untreated urban wastewater discharge. Seawater samples were collected close to the wastewater output (COL) and at a second station about 400 m further off (PAN), before and after a summer increase in population. Prokaryotic communities clustered according to stations, rather than to seasons. While PAN showed a typical, not impacted, marine microbial composition, COL was consistently enriched in Epsilonproteobacteria and Firmicutes. Protist communities showed a peculiar clustering, as COL at springtime stood alone and was dominated by Ciliophora, while the other samples were enriched in Dinophyta. Analysis of alternative, detectable by High-Throughput Sequencing, microbial indicators, including both faecal- and sewage-associated, allowed uncovering the different sources of pollution in coastal and anthropogenically impacted marine ecosystems, underpinning the relevance of High-Throughput Sequencing-based screening as rapid and precise method for water quality management.

Groundwater hydrochemical characterization and quality assessment in the Ghriss Plain basin, northwest Algeria

A base line study involving analysis of groundwater samples from the Ghriss plain plio-quaternary aquifer, in northwest Algeria, was carried out to determine the major elements chemistry and to assess the hydrogeochemical processes and water quality for domestic use. The main groundwater facies in the area belong to the Mg–HCO 3 and Mg–Cl types. Based on TDS classification, 44.5% of the analyzed samples belong to fresh water and the remaining 55.5% to brackish water categories. A comparison of groundwater quality parameters in relation to WHO limits for drinking water shows that the concentrations of TDS, Cl − and NO 3 − exceed the desirable limits in many water samples. The principal component analysis (PCA) technique reveals the contribution of Cl − , Na + , Ca 2+ , K + and Mg 2+ in the salinization process and underlines the contamination of the groundwater with NO 3 − in relation to the widespread application of nitrate fertilizers and/or infiltration of untreated urban wastewater. The groundwater quality index (GWQI) shows that 70.5% of the water samples fall within the excellent-to-good category whereas the remaining samples fall in the poor-to-unsuitable for drinking category.

Experimental study for the reduction of CO2 emissions in wastewater treatment plant using microalgal cultivation

Wastewater treatment plants (WWTPs) contribute to CO2 emissions in atmosphere through direct (biological metabolism) and indirect (fuel combustion) oxidation of organic carbon. This detrimental effect of WWTPs operation can be mitigated by integrating the traditional treatment with a microalgae cultivation pond where CO2 is fixed into autotrophic biomass and the positive side effect of removing nutrients also takes place. To test the feasibility of this modified WWTPs configuration, a pilot-scale 200L raceway pond, operating outdoor, was designed and used for biomass cultivation in untreated urban wastewater. Nitrogen gas enriched with 20% CO2, simulating the exhausted gas of biogas combustion, was supplied continuously during daytime at different flowrates. The dynamics of microalgae growth as well as inorganic carbon and nutrients uptake were studied during the pond start-up and semi-continuous feeding conditions. The absorbed bio-available CO2 was monitored during daylight for different gas flowrates (0.2, 0.4 and 1.0L/min) and for wastewater semi-continuous feeding conditions (0.8L/h). The highest efficiency, equal to 83%, of bio-available CO2 fixation was obtained for the lowest gas flowrate of 0.2L/min., whereas the highest CO2 removal rate of 24.6mg/L/min was reached for the highest gas flowrate of 1.0L/min. Furthermore, this operating condition resulted in the highest microalgae biomass productivity of 28.3g/d/m2. Nutrients removal was complete for each operating condition tested.