Discover the most talked about and latest scientific content & concepts.

Concept: Sanitary sewer


Leaking sewer infrastructure contributes non-point nitrogen pollution to ground- and surface water in urban watersheds. However, these inputs are poorly quantified in watershed budgets, potentially underestimating pollution loadings. In this study, we used inverse methods to constrain dissolved inorganic nitrogen (DIN) inputs from sewage to Nine Mile Run (NMR), an urban watershed in Pittsburgh, Pennsylvania (USA). NMR drains a 1,570 ha watershed characterized by extensive impervious surface cover (38%) and surface and groundwater impacts from combined sewer overflows and leaky sewers. Water samples were collected bi-weekly over two years and intensive sampling was conducted during one summer storm. A nitrogen budget for the NMR watershed was built using known inputs/exports and retention estimates from published studies. These variables were ultimately inverted and sewage DIN inputs constrained using Monte Carlo simulation. Results indicate that DIN contributions from sewage range from 6 to 14 kg ha-1yr-1. When reasonable estimates of inputs are considered, the NMR budget cannot be balanced without taking sewage into account. Further, when conservative estimates of DIN from sewage are included in input calculations, DIN retention in NMR is comparable to high rates observed in other suburban/urban nutrient budgets (maximum likelihood retention estimate=84%).

Concepts: Agriculture, Water, Eutrophication, Water pollution, Hydrology, Monte Carlo, Sanitary sewer, Strategic misrepresentation


We investigated 33 pharmaceuticals and personal care products (PPCPs) with emphasis on anthelmintics and their metabolites in human sanitary waste treatment plants (HTPs), sewage treatment plants (STPs), hospital wastewater treatment plants (HWTPs), livestock wastewater treatment plants (LWTPs), river water and seawater. PPCPs showed the characteristic specific occurrence patterns according to wastewater sources. The LWTPs and HTPs showed higher levels (maximum 3000 times in influents) of anthelmintics than other wastewater treatment plants, indicating that livestock wastewater and human sanitary waste are one of principal sources of anthelmintics. Among anthelmintics, fenbendazole and its metabolites are relatively high in the LWTPs, while human anthelmintics such as albendazole and flubendazole are most dominant in the HTPs, STPs and HWTPs. The occurrence pattern of fenbendazole’s metabolites in water was different from pharmacokinetics studies, showing the possibility of transformation mechanism other than the metabolism in animal bodies by some processes unknown to us. The river water and seawater are generally affected by the point sources, but the distribution patterns in some receiving water are slightly different from the effluent, indicating the influence of non-point sources.

Concepts: Water, Water pollution, Sewage treatment, Sewage, Wastewater, Sanitation, Sanitary sewer, Greywater


Research addressing the occurrence, fate and effects of pharmaceuticals in the aquatic environment has expanded rapidly over the past two decades, primarily due to the development of improved chemical analysis methods. Significant research gaps still remain, however, including a lack of longer term, repeated monitoring of rivers, determination of temporal and spatial changes in pharmaceutical concentrations, and inputs from sources other than wastewater treatment plants (WWTPs), such as combined sewer overflows (CSOs). In addressing these gaps it was found that the five pharmaceuticals studied were routinely (51-94% of the time) present in effluents and receiving waters at concentrations ranging from single ng to μg L(-1). Mean concentrations were in the tens to hundreds ng L(-1) range and CSOs appear to be a significant source of pharmaceuticals to water courses in addition to WWTPs. Receiving water concentrations varied throughout the day although there were no pronounced peaks at particular times. Similarly, concentrations varied throughout the year although no consistent patterns were observed. No dissipation of the study compounds was found over a 5 km length of river despite no other known inputs to the river. In conclusion, pharmaceuticals are routinely present in semi-rural and urban rivers and require management alongside more traditional pollutants.

Concepts: Time, Water, Water pollution, Sewage treatment, Wastewater, Environmental engineering, Sanitary sewer, Combined sewer


Triclosan (TCS) is a multi-purpose antimicrobial agent used as a common ingredient in everyday household personal care and consumer products. The expanded use of TCS provides a number of pathways for the compound to enter the environment and it has been detected in sewage treatment plant effluents; surface; ground and drinking water. The physico-chemical properties indicate the bioaccumulation and persistence potential of TCS in the environment. Hence, there is an increasing concern about the presence of TCS in the environment and its potential negative effects on human and animal health. Nevertheless, scarce monitoring data could be one reason for not prioritizing TCS as emerging contaminant. Conventional water and wastewater treatment processes are unable to completely remove the TCS and even form toxic intermediates. Considering the worldwide application of personal care products containing TCS and inefficient removal and its toxic effects on aquatic organisms, the compound should be considered on the priority list of emerging contaminants and its utilization in all products should be regulated.

Concepts: Water pollution, Sewage treatment, Sewage, Wastewater, Environmental engineering, Effluent, Sanitary sewer, Septic tank


Although contamination of the marine ecosystems by plastics is becoming recognised as a serious pollution problem, there are few studies that demonstrate the contribution made by freshwater catchments. Over a three month period from September to December 2012, at seven localities in the upper Thames estuary, 8490 submerged plastic items were intercepted in eel fyke nets anchored to the river bed. Whilst there were significant differences in the numbers of items at these locations, the majority were some type of plastic. Additionally in excess of 20% of the litter items were components of sanitary products. The most contaminated sites were in the vicinity of sewage treatment works. While floating litter is visible, this study also demonstrates that a large unseen volume of submerged plastic is flowing into the marine environment. It is therefore important that this sub-surface component is considered when assessing plastic pollution input into the sea.

Concepts: River, Sewage treatment, Stream, Sewage, Wastewater, River Thames, Sanitary sewer, Thames Estuary


Sewer systems are among the most critical infrastructure assets for modern urban societies and provide essential human health protection. Sulfide-induced concrete sewer corrosion costs billions of dollars annually and has been identified as a main cause of global sewer deterioration. We performed a 2-year sampling campaign in South East Queensland (Australia), an extensive industry survey across Australia, and a comprehensive model-based scenario analysis of the various sources of sulfide. Aluminum sulfate addition during drinking water production contributes substantially to the sulfate load in sewage and indirectly serves as the primary source of sulfide. This unintended consequence of urban water management structures could be avoided by switching to sulfate-free coagulants, with no or only marginal additional expenses compared with the large potential savings in sewer corrosion costs.

Concepts: Aluminium, Zinc, Wastewater, Water quality, Infrastructure, Water treatment, Sanitary sewer, Integrated urban water management


This study describes the temporal and spatial variability of bacterial communities within a combined sewer system in England. Sampling was conducted over 9 months in a sewer system with intensive monitoring of hydraulic conditions. The bacterial communities were characterized by 16S rRNA gene-targeted terminal restriction fragment length polymorphism analysis. These data were related to the hydraulic data as well as the sample type, location, and time. Temporal and spatial variation was observed between and within wastewater communities and biofilm communities. The bacterial communities in biofilm were distinctly different from the communities in wastewater and exhibited greater spatial variation, while the wastewater communities exhibited variability between different months of sampling. This study highlights the variation of bacterial communities between biofilm and wastewater, and has shown both spatial and temporal variations in bacterial communities in combined sewers. The temporal variation is of interest for in-sewer processes, for example, sewer odor generation, as field measurements for these processes are often carried out over short durations and may therefore not capture the influence of this temporal variation of the bacterial communities.

Concepts: DNA, Ribosomal RNA, 16S ribosomal RNA, Sewage treatment, Restriction fragment length polymorphism, Environmental engineering, Sanitary sewer, Combined sewer


The expected growth in nanomaterial applications could result in increased amounts of nanoparticles entering municipal sewer systems, eventually ending up in wastewater treatment plants and therefore negatively affecting microbial populations and biological nutrient removal. The aim of this study was to ascertain the impact of zinc oxide nanoparticles (nZnO) on the bacterial microbiome of an activated sludge system. A metagenomic approach combined with the latest generation Illumina MiSeq platform and RDP pipeline tools were used to identify and classify the bacterial microbiome of the sludge. Results revealed a drastic decrease in the number of operational taxonomic units (OTUs) from 27 737 recovered in the nZnO-free sample to 23 743, 17 733, and 13 324 OTUs in wastewater samples exposed to various concentrations of nZnO (5, 10 and 100 mg/L nZnO, respectively). These represented 12 phyla, 21 classes, 30 orders, 54 families and 51 genera, completely identified at each taxonomic level in the control samples; 7-15-25-28-20 for wastewater samples exposed to 5 mg/L nZnO; 9-15-24-31-23 for those exposed to 10 mg/L and 7-11-19-26-17 for those exposed 100 mg/L nZnO. A large number of sequences could not be assigned to specific taxa, suggesting a possibility of novel species to be discovered.

Concepts: Bacteria, Species, Sewage treatment, Wastewater, Taxonomic rank, Activated sludge, Sewerage, Sanitary sewer


Combined sewer overflows (CSOs) occur in combined sewer systems when sewage and stormwater runoff are released into water bodies potentially contaminating water sources. CSOs are often caused by heavy precipitation and are expected to increase with increasing extreme precipitation associated with climate change.

Concepts: Water, Climate, Water pollution, Surface runoff, Stormwater, Sanitary sewer, Clean Water Act, Sanitary sewer overflow


Multidrug-resistant Enterobacteriaceae pose a significant threat to public health. We aimed to study the impact of sewage treatment effluent on antibiotic resistance reservoirs in a river.

Concepts: Bacteria, Antibiotic resistance, Natural environment, Water pollution, Sewage treatment, Sewage, Wastewater, Sanitary sewer