The Brisbane River estuary is an anthropogenically-impacted waterway in southeast Queensland, Australia. The estuary is over 80 km long and flows through an urbanised region. It receives over 500 t ...per year of total nitrogen (N) from direct point-source discharges in addition to sporadic flood loads of N from an agriculturally impacted upper catchment. Comprehensive water quality monitoring data for the estuary have been collected from at least 2001. This monitoring data includes ambient nutrient concentrations in the estuary, nutrient concentration and volume of the catchment inflows, and nutrient concentration and volume of point source discharges. This long-term data from a range of sources was used to determine temporal and spatial variations in concentrations, forms, stores and loads of N along the estuary for the period 2001 to 2022. Results showed that, during low-flow periods, the store of N in the mid-upper estuary (33–81 km upstream) is significantly determined by point-source discharges to this reach, and therefore the store of N can be modelled. Model parameters are the daily point source loads, a point source load decay factor, and a background constant store. In the lower estuary (0–33 km upstream) N store can be accurately determined based on dilution with seawater, with point sources not having significant influence on total N in the reach. Total N from large flood events was found to largely pass through the estuary without detectable removal processes, delivering catchment derived N directly to coastal waters. This work informs potential application of nutrient offsets in the estuary, guiding where and when offset options will be effective to mitigate the water quality impacts of point-source nutrients.
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•Managing water quality impacts of point source nitrogen in estuaries depends on flow.•In low flow, N concentration is determined by point sources and in-channel processes.•N can be modelled by decay in the upper estuary and dilution in the lower estuary.•In flood flow, diffuse nitrogen dominates load and is delivered to coastal waters.•Offsets must target the N source or location of water quality impact to match flow.
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Despite the microbeads from cosmetic products do not contribute with high percentages to the microplastic pollution, they can pose a threat to the environment, being discharged into ...the water bodies and just partially blocked by the wastewater treatment plants. As environmental associations have been fighting for the abolition of microplastics in PCCPs, in many countries measures have been taken and bans are already operational or in process. Some cosmetic companies have voluntarily renounced the use of microbeads and some voluntary certifications of PCCPs prohibit their use.
PCCPs recently analysed can contain levels of microbeads reaching 50,391 per g and can contribute with every single use to the introduction of 229,000 microbeads into the domestic sewage. Given the spread and danger of these pollutants, the problem is global and unthinkable to be solved by banning microplastic-containing products only in some countries, thus a general ban would be necessary.
Microplastic fibers, also known as microfibers, are the most abundant microplastic forms found in the environment. Microfibers are released in massive numbers from textile garments during home ...laundering via sewage effluents and/or sludge. This review presents and discusses the importance of synthetic textile-based microfibers as a source of microplastics. Studies focused on their release during laundering were reviewed, and factors affecting microfiber release from textiles and the putative role of wastewater treatment plants (WWTPs) as a pathway of their release in the environment were examined and discussed. Moreover, potential adverse effects of microfibers on marine and aquatic biota and human health were briefly reviewed. Studies show that thousands of microfibers are released from textile garments during laundering. Different factors, such as fabric type and detergent, impact the release of microfibers. However, a relatively smaller number of available studies and often conflicting findings among studies make it harder to establish definitive trends related to important factors contributing to the release of microfibers. Even though current WWTPs are highly effective in capturing microfibers, due to the presence of a massive number of microfibers in the influent, up to billions of fibers per day are released through effluent into the environment. There is a need to establish standardized protocols and procedures that can allow meaningful comparisons among studies to be performed.
The history of China's municipal wastewater management is revisited. The remaining challenges in wastewater sector in China are identified. New concept municipal wastewater treatment plants are ...highlighted. An integrated plant of energy, water and fertilizer recovery is envisaged.
China has the world's largest and still growing wastewater sector and water market, thus its future development will have profound influence on the world. The high-speed development of China's wastewater sector over the past 40 years has forged its global leading treatment capacity and innovation ability. However, many problems were left behind, including underdeveloped sewers and sludge disposal facilities, low sustainability of the treatment processes, questionable wastewater treatment plant (WWTP) effluent discharge standards, and lacking global thinking on harmonious development between wastewater management, human society and the nature. Addressing these challenges calls for fundamental changes in target design, policy and technologies. In this mini-review, we revisit the development history of China's municipal wastewater management and identify the remaining challenges. Also, we highlight the future needs of sustainable development and exploring China's own wastewater management path, and outlook the future from several aspects including targets of wastewater management, policies and technologies, especially the new concept WWTP. Furthermore, we envisage the establishment of new-generation WWTPs with the vision of turning WWTP from a site of pollutant removal into a plant of energy, water and fertilizer recovery and an integrated part urban ecology in China.
The emerged threat of microplastics (MPs) in aquatic ecosystems is posing a new challenges in environmental management, in particular the civil Wastewater Treatment Plants (WWTPs) which can act both ...as collectors of MPs from anthropic use and as a source to natural environments. In this study, MP fate was investigated in one of the biggest WWTPs of Northern Italy, built at the beginning of the 2000s and which serves a population equivalent of about 1,200,000, by evaluating their presence at the inlet (IN), the removal efficiency after the settler (SET) and at the outlet (OUT), and their transfer to sludge. Samples were collected in three days of a week and plastic debris was characterized in terms of shape, size and polymer composition using the Fourier Transform Infrared Microscope System (μFT-IR). The number of detected MPs was 2.5 ± 0.3 MPs/L in the IN, 0.9 ± 0.3 MPs/L after the SET and 0.4 ± 0.1 MPs/L in the OUT, indicating a total removal efficiency of 84%. However, considering that this WWTP treats about 400,000,000 L wastewaters/day, the potential release of MPs to the receiving aquatic system would be approximately 160,000,000 MPs/day, mainly polyesters (35%) and polyamide (17%). Furthermore, a great amount of MPs removed from wastewater was detected in the recycled activated sludge, with 113 ± 57 MPs/g sludge dry weight, corresponding to about 3,400,000,000 MPs deposited in the 30 tons of sludge daily produced by this WWTP. Given the possible re-use of WWTP sludge in fertilizers for agriculture, our results highlight that WWTPs could represent a potential source of MPs also to agroecosystems.
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•Selected Wastewater Treatment Plant (WWTP) removes the 84% of microplastics (MPs).•160,000,000 MPs were released daily by selected WWTP.•3,400,000,000 MPs were deposited daily in 30 tons of sludge by selected WWTP.•WWTPs are a source of MPs in both aquatic and terrestrial environment.
Microplastics, as emerging contaminants in the global environment, have become a cause for concern for both academics and the public. The present understanding of microplastic pollution is primarily ...focused on marine environments, and less attention has been given to freshwater environments, in particular, to urban rivers. In this study, microplastics were sampled from surface water and sediments in 14 sites located in the lower course of the Pearl River. These sampling sites are located along Guangzhou of South China, with built-up areas being the dominant land use. The abundances of microplastics in surface water and sediments ranged from 379 to 7924 items·m−3 and 80 to 9597 items·kg−1, respectively. Polyethylene and polypropylene were the common types of microplastics, together accounting for 64.3% and 73.8% of surface water and sediment samples, respectively. Fibers were the dominant microplastic shapes in both water and sediment samples. The abundances of microplastics varied in surface water and sediments with each site, which might be affected by multiple factors. Our results indicated that wastewater treatment plants (WWTP) could reduce microplastics from municipal sewage which was finally discharged into the Pearl River along Guangzhou.
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•Microplastics in the Pearl River along Guangzhou were investigated for the first time.•Fibers were detected in both surface water and sediment samples.•PE and PP were the dominant polymer types in surface water and sediments.•WWTP in Guangzhou could reduce microplastic pollution in the municipal sewage.
Pathogenic bacteria in wastewater are generally considered to be efficiently removed in biological wastewater treatment plants. This understanding is almost solely based on culture-based control ...measures, and here we show, by applying culture-independent methods, that the removal of species in the genus
was less effective than for many other abundant genera in the influent wastewater.
was one of the most abundant genera in influent wastewater at 14 municipal wastewater treatment plants and was also abundant in the "clean" effluent from all the plants, reaching up to 30% of all bacteria as analyzed by 16S rRNA gene amplicon sequencing. Metagenomic analyses, culturing, genome sequencing of
isolates, and visualization by fluorescent
hybridization (FISH) confirmed the presence of the human-pathogenic
and
in both influent and effluent. The main reason for the high relative abundance in the effluent was probably that
cells, compared to those of other abundant genera in the influent, did not flocculate and attach well to the activated sludge flocs, leaving a relatively large fraction dispersed in the water phase. The study shows there is an urgent need for new standardized culture-independent measurements of pathogens in effluent wastewaters, e.g., amplicon sequencing, and an investigation of the problem on a global scale to quantify the risk for humans and livestock.
The genus
was unexpectedly abundant in the effluent from 14 Danish wastewater treatment plants treating municipal wastewater, and the species included the human-pathogenic
and
Recent studies have shown that
is common in wastewater worldwide, so the study indicates that discharge of members of the genus
may be a global problem, and further studies are needed to quantify the risk and potentially minimize the discharge. The study also shows that culture-based analyses are insufficient for proper effluent quality control, and new standardized culture-independent measurements of effluent quality encompassing most pathogens should be considered.
In the present study, three different artificial intelligence based non-linear models, i.e. feed forward neural network (FFNN), adaptive neuro fuzzy inference system (ANFIS), support vector machine ...(SVM) approaches and a classical multi-linear regression (MLR) method were applied for predicting the performance of Nicosia wastewater treatment plant (NWWTP), in terms of effluent biological oxygen demand (BOD
), chemical oxygen demand (COD
) and total nitrogen (TN
). The daily data were used to develop single and ensemble models to improve the prediction ability of the methods. The obtained results of single models proved that, ANFIS model provides effective outcomes in comparison with single models. In the ensemble modeling, simple averaging ensemble, weighted averaging ensemble and neural network ensemble techniques were proposed subsequently to improve the performance of the single models. The results showed that in prediction of BOD
, the ensemble models of simple averaging ensemble (SAE), weighted averaging ensemble (WAE) and neural network ensemble (NNE), increased the performance efficiency of artificial intelligence (AI) modeling up to 14%, 20% and 24% at verification phase, respectively, and less than or equal to 5% for both COD
and TN
in calibration phase. This shows that NNE model is more robust and reliable ensemble method for predicting the NWWTP performance due to its non-linear averaging kernel.
Microplastics have been identified as an emerging pollutant due to their irrefutable prevalence in air, soil, and particularly, the aquatic ecosystem. Wastewater treatment plants (WWTPs) are seen as ...the last line of defense which creates a barrier between microplastics and the environment. These microplastics are discharged in large quantities into aquatic bodies due to their insufficient containment during water treatment. As a result, WWTPs are regarded as point sources of microplastics release into the environment. Assessing the prevalence and behavior of microplastics in WWTPs is therefore critical for their control. The removal efficiency of microplastics was 65 %, 0.2–14 %, and 0.2–2 % after the successful primary, secondary and tertiary treatment phases in WWTPs. In this review, other than conventional treatment methods, advanced treatment methods have also been discussed. For the removal of microplastics in the size range 20–190 μm, advanced treatment methods like membrane bioreactors, rapid sand filtration, electrocoagulation and photocatalytic degradation was found to be effective and these methods helps in increasing the removal efficiency to >99 %. Bioremediation based approaches has found that sea grasses, lugworm and blue mussels has the ability to mitigate microplastics by acting as a natural trap to the microplastics pollutants and could act as candidate species for possible incorporation in WWTPs. Also, there is a need for controlling the use and unchecked release of microplastics into the environment through laws and regulations.
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•Smaller microplastics (MPs) <100 μm are not effectively separated by conventional WWTPs.•Granules and fragments were easier to separate than microfibers and pellet shaped MPs.•Blue mussels, lugworms and sea grasses are candidate species for MPs' bioremediation.•Rapid sand filters and membrane bioreactors can remove 97 % and 99 % MPs respectively.
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