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Artisanal and small-scale gold mining (ASGM) has made several environmental impacts, resulting in the significant siltation of water bodies due to the deposition of sediments on riverbanks. Based on this perspective, this study aims to investigate the water bodies and regions most impacted by mining activities, especially in relation to the increase in the Total Suspended Solids (TSS) caused by ASGM, focusing on the territories of Suriname and French Guiana, over the period from 2017 to 2023, through the creation of an algorithm in Google Earth Engine. This research also aims to map and describe active mining in this region using the Classification and Regression Tree (CART) method, which achieved an overall accuracy of 82% and a kappa index of 0.77. The results reveal that from 2017 to 2024, there was an increase of 148.09 km2 in mining, with an average increase in TSS of up to 167 mg/L in water bodies most affected by mining activities. Finally, the continued importance of using remote sensing technologies, such as GEE, together with innovative methodological approaches, to monitor and manage natural resources in a sustainable manner is highlighted.

Abstract Urbanization and industrialization in this modern time actually cause less availability of daily based water. In searching of a preferable solution to overcome this critical problem, waste water treatment seems to be considered as a much valuable option for reusing water. For this, sewage water treatment plants (STPs) are widely used. But this solution is actually ironical, as STP treatment causes hazardous damage to the environment in treating waste water. This system needs lots of harmful chemicals, high energy, and high build-up to operate the process. But a newly considered technology has come to counteract all these problems of STPs and the method is ‘Vermifiltration’. In this technique, earthworms are used to treat waste water. Earthworm’s body acts as biofilter and it can reduce higher percentage of BOD, COD, TSS from the waste water compared to the STPs. Earthworms eat up the sewage, making them treated, neutralized, and non-harmful and finally excrete them with several useful microorganisms. The symbiotic activity between earthworms and microorganisms works to filter the waste water. This method is completely odour less and harmless. No sludge is formed. With having all these characteristics, vermifiltration becomes much better option for the environment. In this review, the method of vermifiltration, its limiting factors, utilization and future developments are properly discussed.

Managing total suspended solids (TSS) in inland water is crucial for maintaining water quality and aquatic ecosystems. To obtain spatial data, the conventional method of point sampling TSS is a time- and labor-intensive task. Thus, recent efforts have focused on using satellite imagery to estimate TSS. Previous studies have used empirical method and machine learning model with multispectral satellite bands; however, these are limited to specific study areas and the amount of data is insufficient. This study aimed to build a generalized estimating model that can generally estimate the spatial and temporal variations in TSS concentrations in an extensive region by integrating the Water Quality Monitoring System with Sentinel-2 satellite observations using deep learning algorithms. This would provide comprehensive coverage of continental terrain, enabling consistent acquisition of satellite data and computation of the TSS across four major rivers in South Korea. Deep learning algorithms can generally estimate TSS concentrations over large areas. We found that the convolutional neural network (CNN) model was more accurate than traditional regression and other models, with a Nash-Sutcliffe efficiency (NSE) of 0.758. These findings indicate that it is possible to estimate TSS concentrations in ungauged areas, allowing the acquisition of extensive and continuous spatiotemporal datasets for organic micropollutants. This would be of great assistance in monitoring micropollutants in the four major rivers in South Korea.

AbstractSub-Saharan Africa faces a number of essential issues, including water quality. As such, evaluating the surface water quality of lakes and reservoirs is a crucial part of environmental monitoring and management. Especially in a region where these water bodies serve as a source of livelihood for communities living around them. Water quality parameters (WQPs) are usually taken from the site and sent to the laboratory for measurement and analysis. However, this traditional method is time-consuming, costly, and labor-intensive. Combining geographic information system and remote sensing (RS) allows researchers to analyze WQPs more conveniently. This study, therefore, used RS technology to map and estimate WQPs and correlated it with in-situ measurement. Using the empirical regression model and Landsat 8, WQPs such as chlorophyll-a (Chl-a), total suspended solids (TSS) and turbidity were estimated. The results from RS were correlated with the in-situ measurements of water quality. The results showed that the in-situ Chl-a levels varied from 0.206 to 13.5 mg/L, averaging 5.1 mg/L. The Chl-a values estimated from Landsat 8 had R2 of 0.883 and 0.853, respectively, for both periods (17 December 2022 and 16 March 2023). The green band (B3) was more instrumental in detecting Chl-a. The in-situ measurement for TSS ranged between 18 and 48 mg/L, with a mean value of 28.7 mg/L. These readings were low and within tolerable bounds of 50 mg/L. High TSS concentrations were found near farms and communities with a significant influx of silt into the surrounding lake. The comparison of in-situ water quality and the reflectance from satellite data showed that the turbidity estimated from the sensor from the two periods has R2 > 0.65. The study showed that the combination of the Landsat image and in-situ measurement offers great ways to provide timely and affordable estimation from WQPs.

This study aims to establish the optimal regression model for predicting total suspended solids (TSS) and Turbidity based on in situ data and spectral regions of Sentinel-2 images. Various machine learning models were evaluated, including Multilayer Perceptron Regression (MLPR), Random Forest Regression (RFR), AdaBoost Regression (ABR), Multiple Linear Regression (MLR), and K-Nearest Neighbors Regression (KNNR). These models were applied to different band combinations of spectral regions: visible (VIS), near-infrared (NIR), shortwave-infrared (SWIR), VIS+NIR (VNIR), and VIS+NIR+SWIR (VNIR+SWIR). The study results revealed that the MLR model, while not the best performer during training (R2 = 0.89 for TSS and R2 = 0.66 for turbidity), did not exhibit overfitting, with corresponding R² values in testing being 0.80 and 0.42, respectively. Variable selection for MLR models identified optimal spectral bands: B3, B5, B6, B8, B11, and B12 for TSS, and B4, B8, B11, and B12 for Turbidity. The final no-intercept multiple linear regression models achieved R2 = 0.88 for TSS and R2 = 0.62 for turbidity. Performance metrics for TSS were superior, with lower MAE, MSE, and RMSE compared to Turbidity. This study underscores the efficacy of using MLR models with selected spectral bands for accurate and generalizable predictions of TSS and turbidity.

This study aims to establish the optimal regression model for predicting total suspended solids (TSS) and Turbidity based on in situ data and spectral regions of Sentinel-2 images. Various machine learning models were evaluated, including Multilayer Perceptron Regression (MLPR), Random Forest Regression (RFR), AdaBoost Regression (ABR), Multiple Linear Regression (MLR), and K-Nearest Neighbors Regression (KNNR). These models were applied to different band combinations of spectral regions: visible (VIS), near-infrared (NIR), shortwave-infrared (SWIR), VIS+NIR (VNIR), and VIS+NIR+SWIR (VNIR+SWIR). The study results revealed that the MLR model, while not the best performer during training (R2 = 0.89 for TSS and R2 = 0.66 for turbidity), did not exhibit overfitting, with corresponding R² values in testing being 0.80 and 0.42, respectively. Variable selection for MLR models identified optimal spectral bands: B3, B5, B6, B8, B11, and B12 for TSS, and B4, B8, B11, and B12 for Turbidity. The final no-intercept multiple linear regression models achieved R2 = 0.88 for TSS and R2 = 0.62 for turbidity. Performance metrics for TSS were superior, with lower MAE, MSE, and RMSE compared to Turbidity. This study underscores the efficacy of using MLR models with selected spectral bands for accurate and generalizable predictions of TSS and turbidity.

Granular activated carbon (GAC) filtration is a commonly used method for advanced wastewater treatment. Filters can be operated continuously or discontinuously, with continuous operation not requiring feed flow interruption for backwashing and circulation (B/C). This study investigated the influence of B/C on the effluent quality of continuous filters. Two continuous GAC filters were operated for 1.5 years, with analysis of dissolved substances and particulate matter in the influent and effluent. The results indicated that various B/C modes had no impact on the removal of dissolved organic carbon and organic micropollutants (OMP), achieving an OMP removal of over 70% after 5,600 treated bed volumes (m3 treated wastewater per m3 GAC). However, it was evident that continuous B/C over 2–4 h resulted in increased turbidity, total suspended solids over 30 mg/L and total phosphorus concentrations of 1.3 mg/L in the filter effluent. Additionally, the study demonstrated that longer and more intensive B/C processes resulted in GAC size degradation with AC concentrations of up to 6.9 mg/L in the filter effluent, along with a change in GAC particle size. Furthermore, the importance of pre-filtration in reducing particulate matter in the filter influent and decreasing hydraulic head loss could be demonstrated. HIGHLIGHTS Operation of two continuous granular activated carbon (GAC) filters.; Different backwashing and circulation (B/C) modes were investigated.; Dissolved substances removal (DOC and micropollutants) showed no dependence on B/C mode.; Intensive and long-lasting B/C resulted in GAC abrasion and increased particulate matter and activated carbon concentration in filter effluent.; Pre-filtration was necessary for filter operation.;

The present case study is the evaluation of the efficiency of sewage treatment plants (STP) of Bikaner city (Rajasthan), India. Bikaner city have two sewage treatment plants which cumulatively treat 52 million litre per day (12 MLD and 40 MLD) wastewater. Both STPs work on sequencing batch reactor technology. The performance of 40 MLD is conducted for 6 months duration (July to December 2022). The inlet and outlet wastewater samples are collected. Samples are analysed for pH, total suspended solids (TSS), Biological oxygen demand (BOD), phosphate and sulphate. The overall removal efficiency of STPs is in the order of TSS > BOD > Sulphate > Phosphate > pH. The results reveal that both STPs are considered efficacious. It is recommended that frequent monitoring and assessment should be done for proper functioning of STP.

Yellowtail kingfish (Seriola lalandi), a marine species, has recently been cultured in recirculation aquaculture systems (RAS). A challenge regarding faecal waste management of farming yellowtail kingfish in RAS is their poor faecal integrity. One approach to improve faecal waste management is to enhance nutrient digestibility and thus faecal waste production, which can be achieved through the addition of emulsifiers to the feed. We assessed the effect of emulsifier supplementation on nutrient digestibility, bile acid balance, faecal waste production and characteristics of yellowtail kingfish. This was investigated by using four experimental diets differing in emulsifier supplementation, where fish were fed restrictively (36 days). One diet without emulsifying supplements served as control. Three types of emulsifiers were tested (1) E484, composed of Glyceryl polyethyleneglycol ricinoleate; (2) Lysophospholipids (LPL) combined with lecithin; (3) Sodium taurocholate (STC). The results showed that the STC diet numerically improved fat digestibility and had a positive bile acid balance, which indicated an accumulation of dietary bile acids in the body bile acid pool. Despite a negative bile acid balance, the LPL diet improved fat digestibility as well. A negative bile acid balance shows that the daily amount of faecal bile acid loss exceeds the daily amount of dietary bile acid intake. Fish fed the E484 diet had more faeces removed than the other diets, whilst non-recovered faeces or faecal characteristics were not affected. In conclusion, the current study shows that supplementing both sodium taurocholate (STC), and the combination of Lysophospholipids (LPL) and lecithin can improve fat digestibility in yellowtail kingfish, but emulsifier supplementation does not improve faecal waste management.

The model developed in this paper is an improved equation for the longitudinal dispersion coefficient, which is an important parameter used to monitor and check the assimilatory capacity of rivers. This research incorporates total suspended solids (Ss) and total dissolved solids (Ds) to other selected functional parameters in order to investigate the contributions of Ss and Ds on the longitudinal dispersion coefficient. The results obtained from research indicates that the presence of Ss and Ds affects longitudinal dispersion coefficient as it reduces the magnitude of Dl values. The measured values of longitudinal dispersion coefficient estimated in this study vary between 71 and 104.4 m2 s-1. The percentage of Dr values estimated to be within 0.0 and 0.3 were 50.0% and within −0.3 and 0.0 were 50% for the developed equation and this indicates a degree of accuracy of 100.0%. While for Seo and Cheong, the percentage of Dr values determined to be within 0.0 and 0.3 were 63.3% and within −0.3 and 0.0 were 30% and gives a degree of accuracy of 93.3% and others are poor. SE, NME and MME results show a high accuracy for the derived equation revealing the adequacy of the derived equation in the estimation of D. HIGHLIGHTS The study accounts for the influence of total suspended solids and total dissolved solids on the dispersion coefficient.; The assimilatory capacity of the river; that is, the ability of the river to absorb the waste.; The re-aeration capacity of the river.; Specific distribution of polluting and toxic materials along a stretch of the river for a pattern of effluent discharges.; Water quality parameters monitoring and evaluation.;

Blood clam or blood cockle (Anadara granosa) is a clam species with high calcium carbonate (CaCO3) and chitin content; these compounds are commonly used in coagulation water treatment. This study examined the capacity of blood cockle shells (BCS) as an innovative natural coagulant in the form of unmodified powder (BCSP) and chitosan extracted from the shells (BCSC) to reduce TSS and turbidity of well-water. SEM and FTIR analysis were conducted to analyse the characteristics of the media. The coagulant dose, pH of the water sample, and settling time were investigated using a jar test experiment to determine the optimum condition for each experimental system. Rapid mixing (1 min at 120 rpm) was followed by slow mixing (10 min at 60 rpm), followed by settling times ranging from 10 to 30 min. The optimum settling time was 30 min, after which 76% TSS and 76% turbidity were removed using 75 mg/l of BCSP at pH 4. The tests with BCSC resulted in 80% TSS and 81% turbidity removal with 200 mg/l of BCSC at pH 5 and a settling time of 30 min. The results were compared to the performance of alum (Al2(SO4)3·18H2O), a commercial chemical coagulant. Under similar dosage (200 mg/L) and pH (= 6) conditions, alum reduced turbidity and TSS by 95% and 97%, respectively. These results indicate that blood cockle shell-based coagulant is a promising environmental-friendly material that can compete and possibly replace conventional chemical coagulants in water treatment systems.

Jakarta Bay is a bay supporting the economy of thousands of nearby fishermen. Therefore, the reclamation in Jakarta Bay raises many environmental, economic, and social problems. During this reclamation, dredging and stockpiling activities increase the turbidity of the waters. This research aims to determine the changes in the distribution of total suspended solids (TSS) after reclamation using Sentinel 2A satellite imagery from 2016 to 2022. This research implemented the previous algorithm to produce the distribution of TSS in Jakarta Bay for attaining TSS values from Sentinel 2A satellite imagery processed by Google Earth Engine with overlay analysis method in a geographic information system. Spatial data were obtained by extracting TSS values using the previous estimation algorithm, namely the Budhiman algorithm, with a correlation coefficient of -0.745 and NMAE of 0.167. Based on the data processing results, it was found that the distribution of TSS from 2016 to 2022 was at a moderate level, which had a relatively significant influence on fisheries, requiring the fishermen to go to the open sea farther from the coast. This shows that reclamation carries no impact on the life of marine biota in Jakarta Bay.

The constant production of solids in intensive shrimp and tilapia culture can affect the performance of macroalgae when cultivated in an integrated system, and little is known about culture structures that enhance the performance of macroalgae in biofloc systems. The objective of this work was to evaluate different depths of culture structure for the macroalgae Ulva lactuca in an integrated system with Litopenaeus vannamei and Oreochromis niloticus in a biofloc system. The experiment lasted 70 days, with six systems composed of: a 16 m3 shrimp tank, a 3 m3 tilapia tank, and a 3 m3 macroalgae tank, with water recirculation between tanks. Two treatments were carried out, shallow float, with a structural depth of 10 cm, and bottom float, where the depth was kept at 30 cm from the surface. The shallow float resulted in a growth rate of up to 0.95 ± 0.54% day−1, with biomass loss only at the end of the culture due to the high density of macroalgae, decreasing temperature, and increasing solids concentration. The bottom float had biomass loss throughout the culture cycle. The integrated culture of shrimp, fish, and macroalgae is feasible with the use of shallow floats within 10 cm from the surface.

In this study considering total suspended solids (TSS) parameter monitored in a stream watershed, the predictability of upstream values from downstream data was investigated using regression analysis, which were applied to linear, power, exponential, and quadratic functions, and artificial neural networks (ANNs) method. The data were obtained within the scope of sampling studies carried out 40 times between June 2019 and March 2020 at eight monitoring stations selected in the Sera Stream Watershed (Trabzon). The monitoring stations were divided into two groups as upstream, the first four, and downstream, the last four, stations. Half of downstream data (two stations) was used for training, a quarter (one station) for validation, and the rest (one station) for testing. Two models with different combinations of independent variables were established. In the first model (M1), only the TSS values, and in the other model (M2), the month and week information of the sampling dates were digitized and used as independent variables, in addition to the TSS values. Root mean square error, mean absolute error, and Nash-Sutcliffe (NS) efficiency coefficient statistics were used to evaluate the model and method performances. Compared to other functions, the power one had the best estimation results in the regression analysis. On the other hand, the ANNs method gave better results than the regression analysis. In both methods, M2 performed better overall. In the ANNs method, the NS efficiency coefficients obtained from M1 and M2 were calculated as 0.980 and 0.997, respectively, for the training, and 0.978 and 0.978, respectively, for the testing data sets. Considering the efficiency values, it has been understood that the use of date information as an independent variable will positively affect the model performance in the stream TSS modeling studies. Within the scope of this study, it has been concluded that upstream TSS values can be successfully estimated from downstream TSS data in stream watersheds.

Mineral wool has been used as a filter medium that reaches approximately 95% removal efficiency of total suspended solids (TSS) on a laboratory scale. However, there is no research available has been applied on a larger scale. Hence, this study investigated the ability of mineral wool to remove TSS in two separate segments of the Cikapayang River at different seasons. This analysis utilizes a mineral wool type I, with a dimension of 180×30×120 cm placed in segment 2, and a mineral wool type II with a dimension of 325×30×100 cm placed in segment 9. Samples were taken using the grab sampling method to analyze the TSS concentration before and after being filtered by mineral wool. This investigation concluded that mineral wool could reduce the TSS concentration by up to 65%, and the removal capacity increased by about 6.82% during the dry season. The concentration of TSS in the dry season positively correlates with the increase in the removal capacity of the media. Mineral wool of type I in segment 2 had a better removal ability (31.43%) than type II in segment 9 (14.71%). This research shows that mineral wool can be used as a support material in sanitation sites in large cities experiencing quality degradation in their water bodies.

The purpose of this work is to evaluate the performance of the anaerobic baffled reactor (ABR) for on-site primary treatment of domestic wastewater in rural areas of Iraq. The performance of the three-chamber ABR has been investigated at four different hydraulic retention times (HRTs) ranging from 6 to 36 h. The results showed that the chemical oxygen demand (COD) removal efficiency is enhanced with increasing HRT, where it was recorded at 75, 71, 63, and 56% removals rate of COD at HRTs of 36, 24, 12, and 6 h, respectively. The mean steady-state removals of total suspended solids are 91, 78, 72, and 67% at HRTs of 36, 24, 12, and 6 h, respectively. Also, it was shown that there was low-nutrients removal within the ABR. Consequently, the effluent ABR wastewater needs to be post-treated before being discharged to the receiving water bodies. In general, it is concluded that the ABR could introduce a solution for on-site primary treatment of domestic wastewater in rural communities in Iraq.

The structure of 9-year time series data for Sea Surface Temperature (SST), Chlorophyll a (Chl-a) and Total Suspended Solids (TSS), derived from the Visible Infrared Imaging Radiometer Suite (VIIRS), was examined in this study. Authors found that there exists strong seasonality among the three variables with spatial heterogeneity along the Korean South Coast (KSC). In specific, SST was in phase with Chl-a, but out of phase with TSS by six months. A strong inversed spectral power with six-month phase-lag was found between Chl-a and TSS. This could be attributed to different dynamics and environmental settings. For example, Chl-a concentration seemed to have strong positive correlation with SST indicating typical seasonality of marine biogeochemical processes such as primary production; while a strong negative correlation between TSS and SST might have been influenced by changes in physical oceanographic processes, such as stratification and monsoonal wind-driven vertical mixing. In addition, the strong east–west heterogeneity of Chl-a suggests that the marine coastal environments are predominantly governed by distinct local hydrological conditions and human activities associated with land cover and land use, while the east–west spatial pattern revealed in TSS timeseries was associated with the gradient of tidal forcings and topographical changes keeping tidally induced resuspension low eastward.

A predictive model based on artificial neural networks (ANNs) for modeling primary settling tanks' (PSTs) behavior in wastewater treatment plants was developed in this study. Two separate ANNs were built using input data, raw wastewater characteristics, and operating conditions. The output data from the ANNs consisted of the total suspended solids (TSS) concentration and chemical oxygen demand (COD) as predictions of PSTs’ typical effluent parameters. Data from a large-scale wastewater treatment plant was used to illustrate the applicability of the predictive model proposal. The ANNs model showed a high prediction accuracy during the training phase. Comparisons with available empirical and statistical models suggested that the ANNs model provides accurate estimations. Also, the ANNs were tested using new experimental data to verify their reproducibility under actual operating conditions. The predicted values were calculated with satisfactory results, having an average absolute deviation of

Bu çalışmanın amacı, sürüntü hareketinin yanı sıra yoğun bir askı hareketinin olduğu Sera Deresi Havzası’nda askıda katı madde (AKM) taşınımını gözlemlemek ve ana kol üzerinde inşa edilen tersip bentlerinin (TB) taşınıma olan etkilerini değerlendirmektir. Havzada seçilen 10 AKM gözlem istasyonundan, Haziran-Kasım 2019 döneminde ayda dört kez olacak şekilde su örnekleri toplanmış ve AKM (mg/L) belirlenmiştir. Havzadaki ilk gözlem istasyonunun mansabında yer alan TB1’in taşınan AKM’nin %16,5’ini tutarak mansaba geçişini engellediği ve Sera Gölü’nde havzadan taşınan AKM’nin %69,4 gibi büyük bir kısmının tutulduğu tespit edilmiştir. Havzada işletilmekte olan Derecik isimli akım gözlem istasyonundan (AGİ) seviye okumaları yapılarak ilgili kesitten geçen debiler (Q, m3) belirlenmiş ve AKM yükleri (ton) hesap edilmiştir. TB2 ile TB3 arasında ve Derecik AGİ’nin hemen mansabında yer alan istasyonda ortalama günlük debiler ve AKM yükleri yazın 99.000 m3/gün ile 24,6 ton/gün ve sonbaharda 83.945 m3/gün ile 2,5 ton/gün olarak hesap edilmiştir. Akarsu yataklarına moloz ve hafriyat dökümünün yanı sıra yerleşim birimlerinden yapılan evsel atık su deşarjlarının da AKM miktarının artışında etken olduğu havzada tersip bentleri sayısal olarak yetersiz kalmaktadır. Çok dik ve sarp eğimli orman arazilerine sahip Sera Deresi Havzası’nın membaındaki yan kollar üzerinde de geçirimsiz tersip bentlerinin yanı sıra geçirimli tersip bentlerine de ihtiyaç duyulduğu sonucuna ulaşılmıştır.

Total suspended solids (TSS) and chlorophyll-a (Chl-a) are critical water quality parameters. Focusing on the Pearl River Estuary and its coastal waters, this study compared the performance of XGBoost- and BPNN-based algorithms in estimating TSS and Chl-a levels. The XGBoost-based algorithm demonstrated better performance and was then used to estimate TSS and Chl-a in the Pearl River Estuary and coastal waters from 2000 to 2021. According to our results, TSS and Chl-a were relatively high mainly in the northwest and low in the southeast. Furthermore, values were high in spring and summer and low in fall and winter, with high values emerging near the estuary of the Pearl River. In summer, a band zone with high Chl-a was observed from south of Yamen to south of Hong Kong. In terms of trends, TSS and Chl-a concentrations in the area around the Hong Kong–Zhuhai–Macao Bridge tended to decrease from 2000 to 2021. As the construction of the bridge began, changes in water flow caused by the bridge piers and artificial islands were influenced, the change in the rate of TSS in the west area of the bridge was greater than 0, and the TSS in the upstream area of the west side changed from decreasing to increasing trends. Concerning Chl-a concentrations, the change in the rate in the downstream area of the west side of the bridge was greater than 0. The study may provide a helpful example for similar estuarine and coastal waters in other coastal areas.

Shrimp production in biofloc systems generates excess organic matter that must be removed from the system. Due to its ability to consume natural productivity, the integration of tilapia in shrimp culture could help to reduce the levels of total suspended solids in the biofloc system. The present study aimed to evaluate two stocking densities of tilapia in an integrated culture with shrimp Litopenaeus vannamei reared in a pilot-scale biofloc system. Two stocking densities of tilapia were tested, 35 and 65 fish m-3 in a recirculating system with 10 m3 tanks for shrimp culture and 4 m3 for tilapia culture with water recirculation of 965.66 ± 92.83 L h-1 during 78 days. The initial weight of shrimp was 0.9±0.1 g and of tilapia was 7.1±3.2 g. Shrimps were fed according to the feeding table and fish were underfed to stimulate bioflocs consumption. Selected water quality parameters were monitored during the trial. Tilapia densities did not affect shrimp growth (11.5±1.9 g and 10.1±0.7 g for 35 and 65 fish m-3 treatments, respectively). The tilapia presented a FCR lower than 1, proving that bioflocs were consumed by fish. The clarification time was shorter when compared to other studies with shrimp monoculture. Between the treatments, a reduction of 10 hours in the system clarification occurred when lower fish stocking density was used. The results demonstrate the feasibility of integrated shrimp and tilapia culture on a pilot scale, without compromising shrimp productivity.

The performance of stormwater treatment trains and of their individual green infrastructures was evaluated near Montreal, Canada. Three treatment trains were studied: Train 1 – five bioretention cells in series with a wet retention pond; Train 2 – an infiltration trench in series with a dry detention pond; and Train 3 – Train 2 in series with a wet retention pond. A total of 47 rain events were monitored to quantity the hydrological performance, while water quality samples were taken during 24 rainfall events. During the summer, the bioretention cells led to a reduction in runoff volumes varying from 8 to 100%. Overall, the three studied treatment trains and all of the individual infrastructures, except for the dry pond, provided reductions in the mean concentrations of total suspended solids, chemical oxygen demand, total nitrogen and total phosphorous. Results also showed that the use of a train of stormwater infrastructures can be more effective to reach Quebec's legislated targets than single infrastructures, but only if the infrastructures are sequenced properly. Indeed, the addition of a dry basin at the end of Train 2 affected negatively the removal efficiency of the four studied contaminants. HIGHLIGHTS Hydrological and water quality performance of single and in-series (train) stormwater control infrastructures was assessed.; The use of a train can be more effective for removing contaminants if sequenced properly.; Adding a dry basin at the end of a train affected negatively the removal efficiency of the four studied contaminants.; The mean removal efficiency of total suspended solids was positive during the winter months.;

Study region: The Lake Winnipeg Basin in the northern Great Plains of North America Study focus: Assessment of trends in total nitrogen (TN), total phosphorus (TP) and total suspended solids (TSS) for 18 river stations in the Lake Winnipeg Basin for the period of 1996–2016 using a Weighted Regressions on Time, Discharge and Season (WRTDS) modeling approach. New hydrological insights for the region: We observed rapidly increasing concentrations, loads, and yields of TN, TP and TSS at most of the evaluated river monitoring stations in the eastern half of the basin. In contrast, nutrient and suspended solid loads tended to exhibit decreasing or stationary trends at most of the more western stations. Trends in nutrients and suspended solids typically corresponded to discharge, particularly in the Red-Assiniboine subdrainage where rapidly increasing nutrient loads were almost exclusively associated with runoff patterns. Our findings will serve as a baseline against which future trend assessments can be compared. Moreover, our findings suggest that land management practices aimed at reducing nutrient loads to Lake Winnipeg should be prioritized towards the rivers of the eastern subdrainages of the Lake Winnipeg basin.

The rapid warming of the Arctic has led to permafrost degradation, accelerating the transport of terrestrial materials by rivers. The quantitative assessment of riverine nutrients and total suspended solids (TSS) flux is important to clarify the land–ocean connections in the Arctic. However, much is unknown about the estimates of these components from direct measurements in the Arctic rivers and the response of the components to permafrost degradation. Here, we report the results from the Arctic Great Rivers Observatory (Arctic-GRO) for the six major Arctic rivers (Yenisey, Lena, Ob’, Mackenzie, Yukon, and Kolyma) to investigate the riverine exports of TSS, total dissolved nitrogen (TDN), nitrate (NO3−), bicarbonate (HCO3−), total dissolved phosphorus (TDP), and phosphate (PO43−). The results showed that from 2004 to 2017, the annual TSS, TDN, and NO3− exports to the Arctic Ocean were approximately 106,026 Gg, 692 Gg, and 130 Gg, respectively, and the HCO3−, TDP, and PO43− exports were approximately 79,092 Gg, 32 Gg, and 18 Gg, respectively. There were remarkable variations in component concentrations and fluxes between seasons. More than 80% of the TDN, TDP, PO43−, and TSS exports mainly occurred in spring and summer, and a high HCO3− flux was recorded in summer, while a high NO3− flux in some rivers occurred in winter. The active layer thickness was significantly positively correlated with the annual TDN, NO3−, and HCO3− exports. In addition, the HCO3− flux of the six Arctic rivers increased by 247 Gg per year during 2004–2017. The positive relationship between the active layer thickness and river discharge indicates that permafrost degradation accelerated riverine carbonate, nitrogen, and phosphorus exports. This study demonstrates that riverine exports play an important role both in the Arctic terrestrial and marine ecosystems, and permafrost degradation will likely increase the riverine material exports to the ocean.

Even though wind, water depth, and shear stress are important factors governing sediment resuspension in lakes, their actual relations to total suspended solids (TSS) distribution in natural environments have not been well elucidated. This study aims to elucidate the impact of the wind on the spatio-temporal variation of TSS in Tonle Sap Lake, Cambodia, during low-water (March and June, R2 = 0.49) than the vectorized average (R2 = 0.30) and inverse of the ratio of distance (R2 = 0.31). Spatial interpolation showed that the wind speed and direction on the lake were 50 mg/L) than that in the high-water season. The TSS concentration during the low-water season was empirically described by wind speed (W), water depth (D), and shear stress (τ_wave) with a function of W3, W3/D, and exp(W/D) or exp(τ_wave), depending on the location in the lake. The critical shear stress due to wind-induced waves at most of the places in the lake was higher than the total shear stress indicated. Sedimentation was predominant in December and June, and erosion (siltation) was dominant in March. Most of the siltation in March was dominant in the southern part of the lake.

The current study was performed to test filtration media system performance on quality of water purification and to evaluate optical properties, such as reflection, transmission and absorption intensities for filtered water using a spectrophotometer operating in the range 350–400 nm. Head losses through filtration system at the experiments were equal to 20, 40, and 60 kPa. With the progress of the filtration process and increase in different head loss (from 20 to 60 kPa), both the content of total suspended solids and turbidity in optical properties intensities for filtrated water increased, together with the water cloudiness. It is shown that the intensity of optical properties can be considered a reliable indicator that to determine the need for backwashing of the filtration system. Highlights Local gravel samples are high quality and easy to use in the Egyptian natural environment.; Gravel or sand media filters are particularly suitable for water with a high TSS content.; Optical properties are known to be the best indicator for filtering backwashing.;

This research studies the implementation of artificial neural networks (ANN) in predicting the concentration of total suspended solids (TSS) for the Fei Tsui reservoir in Taiwan. The prediction model developed in this study is designed to be used for monitoring the water quality in the Fei Tsui reservoir. High concentrations of total suspended solids (TSS) have been a crucial problem in the Fei Tsui reservoir for decades. As the Fei Tsui reservoir is a primary water source for Taipei City, this issue impacts the drinking water supply for the city due to etherification problems in the reservoir. 10-year average monthly records and 13-year average annual records have been collected for 26 parameters and correlated with the TSS concentrations to determine the parameters that have a strong relationship with the TSS concentrations. The parameters that were shown to have a strong correlation with the TSS concentration are the trophic state index (TSI), nitrate (NO3) concentration, total phosphorous (TP) concentration, iron concentration (IRON), and turbidity. Linear regression was used to develop the model that estimates the TSS concentration in the Fei Tsui Reservoir. The results show that model 3, a three-layer ANN model that uses three-input parameters namely NO3 concentration, TP concentration, and turbidity, with five neurons, to predict the output parameter which is TSS concentration, produces the highest coefficient of determination (R2) and Willmott Index (WI), which are 0.9589 and 0.9933 respectively, and the lowest root mean square error, which is 0.4753. Based on these performance criteria, model 3 is concluded as the best model to predict TSS concentrations in this study.

Air pollution has become one of the major emerging issues of the 21st century. It is a serious problem for almost every developing country. Due to the rapid increase in population and industrialization, the problem of air pollution has become more serious. Various environmentalists and scientists have conducted a variety of studies and surveys to know about the current situation and further how to deal with these situations. Therefore, this paper aims to analyze the willingness of people living in the Southern region of Lahore to pay for improving the air quality. Statistical Package for Social Sciences software (version 20.0) was applied to determine the relationship between willingness to pay and powerful factors. A short time later stepwise, a linear regression model was built to determine the amount of positive Willingness to pay and to predict the mean value of Willingness to pay. The frequency and percentage of each variable were also determined through SPSS. The results revealed that out of 400 questionnaires filled by the citizens 82% of the citizens of southern Lahore showed positive response as they were in favor of Willingness to pay for improved air quality which shows their deep concern about the rising issue. And only 18% were not ready for Willingness to pay for improved air quality, the only reason for this negative response was the unawareness among the citizens. This shows that more awareness is required to create more knowledge among the citizens of Southern Lahore that bad air quality has so many depressing impacts on their health and well-being.

Purpose. Land use within a watershed affects surface water quality by creating a process by which diffuse pollutants such as suspended solids, trace metals, and nutrients enter rivers and streams. The purpose of this study is to assess pollution-load for Total Suspended Solids (TSS) and some trace metals in runoff samples collected during storm events in selected sub-catchment locations representing different land use areas in an urban watershed; and to determine the effects of land-use on the content of pollutants in stormwater using Event Mean Concentration (EMC). Results. There were high EMC and Site Mean Concentrations (SMC) of TSS in stormwater in the six land-use zones examined, with values ranging from 154.0 mg L−1 to 1464.0 mg L−1; and 216.5 mg L−1 to 1153.4 mg L−1 for EMC and SMC respectively. The total content of suspended solids was significantly high, above the acceptable threshold of 100.0 mg L−1 stipulated by the WHO. The researchers also found a statistically significant variation in TSS loading of stormwater from the commercial land-use areas compared with the other land-use zones. A strong correlation was also observed between the volume of stormwater discharged and the TSS load. However, the concentrations of trace metals in stormwater were low across the land use zones. The commercial districts of the studied cities were found to be major sources of suspended solids in stormwater, and pollution of the urban watersheds leading to the deterioration of the rivers. Scientific novelty. This study attempted to qauntify TSS load in stormwater and determine the contributions of the diffferent urban land-use areas to pollution yield.. It contributes to scientific efforts to directly quantify surface water pollution from nonpoint sources, since little attention has been paid to diffuse pollution, especially in sub-Saharan Africa; and provides baseline data for assessing urban stormwater in low-income countries. Practical value. This study offers guidelines for city authorities to develop land use policies to control surface water pollution and urban waste. The findings may also serve as emperical basis for greater advocacy by civil society organizations for the proper management and control of urban rivers and streams for public health benefits.

The Great Barrier Reef (GBR) is a marine protected area subject to natural and anthropogenic disturbances. Water quality is critical for the health and protecting resilience of GBR coral ecosystems against the synergistic and cumulative pressures of tropical cyclones, marine heat waves, and outbreaks of crown-of-thorns starfish. The concentration of Total Suspended Solids (TSS) is a key water quality parameter measured at multiple spatio-temporal scales from in situ probes to satellite observations. High TSS concentrations can adversely impact coral and seagrasses on the inshore GBR. We present diurnal TSS derived from Himawari-8 Geostationary satellite observations at 10 min frequency and demonstrate its applicability for improved monitoring of GBR water quality. Diurnal TSS obtained from Himawari-8 observations were compared to TSS computed from in situ bio-optical measurements at the Lucinda Jetty Coastal Observatory (LJCO). The coastal waters at LJCO experience diurnal variability of TSS (~7 mg L−1), where magnitude peaks followed the slack tides, and the largest diurnal changes were associated with freshwater discharge residuals from the wet season. Exceedance maps revealed that TSS is above guideline thresholds in the open coastal and mid-shelf waters for ~60% of the valid monthly observations, including during dry season months.

Abstract Objective Kampala Industrial and Business Park (KIBP) is one of the premier and the most successful Ugandan industrial complexes that impact the inner Murchison bay of Lake Victoria. The current study aimed at evaluating the effect of industrial effluents on the physicochemical and microbiological quality of water taken from four different sites along Namanve stream in KIBP, Wakiso district, Uganda. Results All the water quality parameters were below WHO maximum permissible limits except turbidity, electrical conductivity and Escherichia coli count. Mean values of the monitored water quality parameters increased from the point of effluent discharge downstream of Namanve stream.

Turbid water is known to affect aquatic ecosystems. If the spread of turbid water can be predicted, it is expected to lead to the prediction of damage caused by turbid water in rich aquatic ecosystems and aquaculture farms, and to countermeasures against turbid water. In this study, we developed a method for predicting the area of high-turbidity water using machine learning with satellite-observed total suspended solids (TSS) product and relatively readily available meteorological and oceanographic data (rainfall, wind direction and speed, atmospheric pressure, and tide level) in the past and evaluated it for the Kuma River estuary of the Yatsushiro Sea in Japan. The results showed that the highest accuracy was obtained using random forest regression, with a coefficient of determination of 0.552, when the area of high-turbidity water based on the previous day’s TSS product and hourly meteorological and oceanographic data from the previous day were used as inputs. The most important factor for the prediction was the area of high-turbidity water, followed by wind, and tide level, but the effect of rainfall was small, which was probably due to the flood-control function of the river. Our future work will be to evaluate the applicability of the method to other areas, improve the accuracy, and predict the distribution area.

Stormwater runoff from carparks should be treated to remove pollutants before they enter urban waterways; however, differences in traffic characteristics and surrounding land use activities can result in varying first flush pollutant types and concentrations requiring specific treatment approaches. An understanding of potential variations in first flush pollutant characteristics from carparks is necessary to design adequate treatment systems. Stormwater runoff from over 20 runoff events in three different carparks (university, hospital and industrial) in Christchurch, New Zealand were thus analyzed for Total Suspended Solids (TSS) and heavy metals (Zn, Cu and Pb) over a year. Pollutant concentrations were found to vary across the carparks, which were largely driven by land use activities such as traffic count, size of the vehicles, and surrounding topography. Mean concentrations of heavy metals (both dissolved and particulate) and TSS were significantly higher in the industrial carpark than in the other two urban carparks, which had statistically similar mean pollutant concentrations. Specific ratios of metal species (Zn:Cu, and Zn:Pb) were relatively high for the industrial carpark, indicating a greater contribution from the wear and tear of large commercial vehicles. TSS and total Zn wash-off concentrations from the hospital carpark when it was non-operational (passive) were found to be significantly lower than the hospital carpark when it was operational (active), confirming that pollutant concentrations increase with vehicular activity. Rainfall characteristics such as antecedent dry days and rain intensity and duration were found to only have a low positive correlation to pollutant concentrations for all carparks. The findings from this study highlight the importance of considering carpark characteristics in the implementation of on-site stormwater treatment systems.

The water quality in rivers around Dhaka is deteriorating very fast given extensive sources of pollutants associated with rapid urbanisation and industrialisation. This paper introduced a water quality index (WQI) utilising Landsat bands 1 to 3 (0.45 to 0.67 µm) against band 5 (1.55 to 1.75 µm). The value of the proposed index varies from – 1 to + 1, whereby around 0 (small positive and negative) indicated probable contamination, if the water depth is around 2 m or above. This approach was developed using Landsat data to study long-term water quality change in the rivers surrounding Dhaka megacity, Bangladesh. The values were converted to total suspended solids (TSS) by utilising observed in-situ data, which showed a clear seasonal influence of water pollution, suggesting it reduces to the background level with the onset of high monsoonal river flows. However, long-term analysis showed that the rivers remain polluted throughout the year, particularly since 2011. The main reason for increasing river water pollution may be linked to the contaminant load which has increased extensively in recent years. The approach developed in this study may be used in other urban rivers, particularly in Asia.

The current study aimed at fostering bacterial growth in BFT aquaculture tanks by early Nile tilapia stocking. Control tanks had no tilapia but received daily applications of dry molasses (NT+) or had tilapia but no C:N ratio adjustment (T-). Experimental tanks had tilapia and received daily application of molasses to adjust the C:N ratio of water to 15:1 (T+). The development of bioflocs in NT+ was insignificant as demonstrated by low levels of settleable solids (SS) and total suspended solids (TSS). Total ammonia nitrogen (TAN) was significantly higher in NT+ than in T+. In the C:N-ratio adjusted tanks, the presence of fish shortened the control of TAN in several days. As nitrite declined in T+, it increased in NT+. The final concentrations of TSS in T+, T- and NT+ were 236 ± 29 mg L-1, 100 ± 32 mg L-1, and 40 ± 22 mg L-1, respectively (p < 0.05). It can be concluded that stable nitrifying and heterotrophic bacterial communities could be attained in BFT aquaculture tanks, before the end of the 4th week of culture, if the bacterial growth is fostered by early Nile tilapia stocking.

Remote-sensing ocean colour studies have already been used to determine coastal water quality, coastal biodiversity, and nutrient availability. In recent years, Unmanned Aerial Vehicles (UAVs) equipped with multispectral sensors, originally designed for agriculture applications, have also enabled water-quality studies of coastal waters. However, since the sea surface is constantly changing, commonly used photogrammetric methods fail when applied to UAV images captured over water areas. In this work, we evaluate the applicability of a five-band multispectral sensor mounted on a UAV to derive scientifically valuable water parameters such as chlorophyll-a (Chl-a) concentration and total suspended solids (TSS), including a new Python workflow for the manual generation of an orthomosaic in aquatic areas exclusively based on the sensor’s metadata. We show water-quality details in two different sites along the Maltese coastline on the centimetre-scale, improving the existing approximations that are available for the region through Sentinel-3 OLCI imagery at a much lower spatial resolution of 300 m. The Chl-a and TSS values derived for the studied regions were within the expected ranges and varied between 0 to 3 mg/m3 and 10 to 20 mg/m3, respectively. Spectral comparisons were also carried out along with some statistics calculations such as RMSE, MAE, or bias in order to validate the obtained results.

Remote sensing of ocean colour has been fundamental to the synoptic-scale monitoring of marine water quality in the Great Barrier Reef (GBR). However, ocean colour sensors onboard low orbit satellites, such as the Sentinel-3 constellation, have insufficient revisit capability to fully resolve diurnal variability in highly dynamic coastal environments. To overcome this limitation, this work presents a physics-based coastal ocean colour algorithm for the Advanced Himawari Imager onboard the Himawari-8 geostationary satellite. Despite being designed for meteorological applications, Himawari-8 offers the opportunity to estimate ocean colour features every 10 min, in four broad visible and near-infrared spectral bands, and at 1 km2 spatial resolution. Coupled ocean–atmosphere radiative transfer simulations of the Himawari-8 bands were carried out for a realistic range of in-water and atmospheric optical properties of the GBR and for a wide range of solar and observation geometries. The simulated data were used to develop an inverse model based on artificial neural network techniques to estimate total suspended solids (TSS) concentrations directly from the Himawari-8 top-of-atmosphere spectral reflectance observations. The algorithm was validated with concurrent in situ data across the coastal GBR and its detection limits were assessed. TSS retrievals presented relative errors up to 75% and absolute errors of 2 mg L−1 within the validation range of 0.14 to 24 mg L−1, with a detection limit of 0.25 mg L−1. We discuss potential applications of Himawari-8 diurnal TSS products for improved monitoring and management of water quality in the GBR.

The COVID-19 pandemic in China in the winter-spring of 2019–2020 has decreased and even stopped many human activities. This study investigates whether there were any changes in the water quality of the Lower Min River (China) during the lockdown period. The time-series remote sensing images from November 2019 to April 2020 was used to examine the dynamics of the river’s total suspended solids (TSS) concentrations in the period. A new remote sensing-based prototype was developed to recalibrate an existing algorithm for retrieving TSS concentrations in the river. The Nechad and the Novoa algorithms were used to validate the recalibrated algorithm. The results show that the recalibrated algorithm is highly consistent with the two algorithms. All of the three algorithms indicate significant fluctuation in TSS concentrations in the Lower Min River during the study period. February (COVID-19 lockdown period) has witnessed a 48% fall in TSS concentration. The TSS in March–April showed a progressive and recovery back to normal levels of pre-COVID-19. The spatiotemporal change of TSS has worked as a good indicator of human activities, which revealed that the decline of TSS in the lockdown period was due largely to the substantially-reduced discharges from industrial estates, densely-populated city center, and river’s shipping. Remote sensing monitoring of the spatiotemporal changes of TSS helps understand important contributors to the water-quality changes in the river and the impacts of anthropogenic activities on river systems.

Unoccupied aircraft systems (UAS, or drones) equipped with off-the-shelf multispectral sensors originally designed for terrestrial applications can also be used to derive water quality properties in coastal waters. The at-sensor total radiance a UAS measured constitutes the sum of water-leaving radiance (LW) and incident radiance reflected off the sea surface into the detector’s field of view (LSR). LW is radiance that emanates from the water and contains a spectral shape and magnitude governed by optically active water constituents interacting with downwelling irradiance while LSR is independent of water constituents and is instead governed by a given sea-state surface reflecting light; a familiar example is sun glint. Failure to accurately account for LSR can significantly influence Rrs, resulting in inaccurate water quality estimates once algorithms are applied. The objective of this paper is to evaluate the efficacy of methods that remove LSR from total UAS radiance measurements in order to derive more accurate remotely sensed retrievals of scientifically valuable in-water constituents. UAS derived radiometric measurements are evaluated against in situ hyperspectral Rrs measurements to determine the best performing method of estimating and removing surface reflected light and derived water quality estimates. It is recommended to use a pixel-based approach that exploits the high absorption of water at NIR wavelengths to estimate and remove LSR. Multiple linear regressions applied to UAS derived Rrs measurements and in situ chlorophyll a and total suspended solid concentrations resulted in 37 and 9% relative error, respectively, which is comparable to coastal water quality algorithms found in the literature. Future research could account for the high resolution and multi-angular aspect of LSR by using a combination of photogrammetry and radiometry techniques. Management implications from this research include improved water quality monitoring of coastal and inland water bodies in order to effectively track trends, identify and mitigate pollution sources, and discern potential human health risks.

Protecting the quality of coastal water bodies requires the assessment of contaminant discharge brought by rivers. Numerous methods have been proposed for calculating sediment and nutrient loads. The most widely used and generally recommended are the flow-weighted mean concentration method (FWMC) and the flow duration rating curve method (FDRC). In the Mediterranean basin, the hydrology is characterized by infrequent but very intense rainfall events. The flows taking place during these periods last only a few hours to a few days but can represent the largest part of the annual flow. The loads associated with these events can also account for most of the annual load. A reinforced water-quality monitoring program (especially during floods) was carried out for five years (August 2015–July 2020) on six tributaries of French Mediterranean lagoons. The loads calculated by FWMC and FDRC methods were very different. Total suspended solid loads calculated by FWMC were on average 5.0 times higher than those calculated by FDRC. Similarly, total phosphorus loads were 3.5 times higher and total nitrogen loads were 1.6 times higher. The results show that too many flood samples can lead to considerable overestimation of particulate loads calculated by the FWMC method. Dissolved nutrients, on the other hand, are much less subject to overestimation.

Although wetlands in temperate regions have been studied for their pollutant remediation potential, the sediment and nutrient retention capacity of natural wetlands in tropical environments remains understudied. In this study, a mass balance approach was used to estimate the amount of sediment and nutrients retained at 40 different study sites located in four natural riverine wetlands in Southwest Ethiopia. Awetu and Boye wetlands retained a substantial amount of total suspended solids (TSS) and nutrients whereas Kofe and Kito wetlands had a net release. Overall, the amount of TSS retained by the four wetlands was estimated to be 6266.5 kg/ha/day. On the other hand, the net retention of Total Organic Nitrogen (TON) and Total Phosphorous (TP) was estimated to be 37.6 kg/ha/day and 40.9 kg/ha/day, respectively. A stepwise multiple regression analysis revealed that anthropogenic activities such as farming, grazing, waste dumping and clay mining were the main variables that negatively affected the retention of TSS and nutrients. Farming alone explained 58% of the variation in TSS retention and cattle grazing explained 25% of the variation in TON retention. Therefore, watershed management interventions considering the mitigation of anthropogenic activities could be considered to reduce sediment and nutrient input and release.

The effluent from copper industries is important in terms of production volume, environmental pollution and cost of treatment and disposal. In addition to its economic reasons, the effluent recovery also reduces the pollutant load. Such cases therefore prove the necessity of investigating different methods for reducing water consumption and effluent generation. This study investigated the minimization of water consumption and effluent production in Khatoon Abad copper refinery plant. For this purpose, the conventional method of reducing water consumption and a new technology called water pinch were explained. The water pinch technology was examined for three pollutant indices (TSS, TDS and turbidity) in three high consumption units of Khatoon Abad copper refinery plant. For TSS, TDS and turbidity as pollutant indices, total 614, 525 and 451 cubic meters of raw water consumption per day equivalent to 40.96, 35 and 30 percent could be saved, respectively. According to the results, the pinch technology could help researchers to make decisions for reducing water consumption and according to the observations, suspended solids are regarded as the basis for reducing water consumption. Minimization of water consumption, Water pinch, Mass transfer networks, Water reuse, Total suspended solids, Turbidity.

The reliability of removal of selected contaminants in three technological solutions of the household sewage treatment plants was analysed in this paper. The reliability of the sewage treatment plant with activated sludge, sprinkled biological deposit and hybrid reactor (activated sludge and immersed trickling filter) was analyzed. The analysis was performed using the Weibull method for basic indicators of impurities, BOD5, COD and total suspended solids. The technological reliability of the active sludge treatment plant was 70% for BOD5, 87% for COD and 66% for total suspended solids. In the sewage treatment plant with a biological deposit, the reliability values determined were: 30% (BOD5), 60% (COD) and 67% (total suspended solids). In a treatment plant with a hybrid reactor, 30% of the BOD5 and COD limit values were exceeded, while 30% of the total suspended solids were exceeded. The reliability levels are significantly lower than the acceptable levels proposed in the literature, which means that the wastewater discharged from the analysed wastewater treatment plants often exceeds the limit values of indicators specified in currently valid in Poland Regulation of the Minister of Environment for object to 2000 population equivalent.

Ecological shifts, between a clear macrophyte-dominated state and a turbid state dominated by phytoplankton and high inorganic suspended solids, have been well described in shallow lake ecosystems. While few documented examples exist in rivers, models predict regime shifts, especially in regulated rivers with high water retention time. Here I quantified ecological shifts in a large, semi-regulated floodplain river during a transition from a turbid- to a clear-water state using water quality, aquatic vegetation and fisheries data from a rigorous, standardized long-term data set. My findings indicate that significant changes occurred in total suspended solids concentration, aquatic macrophyte abundance, native and non-native fish biomass, fish functional feeding guild patterns, fish habitat guild assemblages and fish spawning guild assemblage patterns over a nearly 20-year period in Navigation Pool 8 of the Upper Mississippi River. Transitions in physical and biological indicators were examined to identify mechanisms underlying the ecological shifts. Environmental variables driving fish assemblage changes were identified (total suspended solids and aquatic vegetation) and management-relevant thresholds are presented. Awareness of management thresholds is critical for resource managers to implement measures to prevent the river from moving to a degraded state characterized by high non-native fish abundance and low predatory fish species abundance.

The state of water quality of lakes is highly related to watershed processes which will be responsible for the delivery of sediment, nutrients, and other pollutants to receiving water bodies. The spatiotemporal variability of water quality parameters along with the seasonal changes were studied for Lake Okeechobee, South Florida. The dynamics of selected four water quality parameters: total phosphate (TP), total Kjeldahl nitrogen (TKN), total suspended solid (TSS), and chlorophyll-a (chl-a) were analyzed using data from satellites and water quality monitoring stations. Statistical approaches were used to establish correlation between reflectance and observed water quality records. Landsat Thematic Mapper (TM) data (2000 and 2007) and Landsat Operational Land Imager (OLI) in 2015 in dry and wet seasons were used in the analysis of water quality variability in Lake Okeechobee. Water quality parameters were collected from twenty-six (26) monitoring stations for model development and validation. In the regression model developed, individual bands, band ratios and various combination of bands were used to establish correlation, and hence generate the models. A stepwise multiple linear regression (MLR) approach was employed and the results showed that for the dry season, higher coefficient of determination (R2) were found (R2 = 0.84 for chl-a and R2 = 0.67 for TSS) between observed water quality data and the reflectance data from the remotely-sensed data. For the wet season, the R2 values were moderate (R2 = 0.48 for chl-a and R2 = 0.60 for TSS). It was also found that strong correlation was found for TP and TKN with chl-a, TSS, and selected band ratios. Total phosphate and TKN were estimated using best-fit multiple linear regression models as a function of reflectance data from Landsat TM and OLI, and ground data. This analysis showed a high coefficient of determination in dry season (R2 = 0.92 for TP and R2 = 0.94 for TKN) and in wet season (R2 = 0.89 for TP and R2 = 0.93 for TKN). Based on the findings, the Multiple linear regression (MLR) model can be a useful tool for monitoring large lakes like Lake Okeechobee and also predict the spatiotemporal variability of both optically active (Chl-a and TSS) and inactive water (nutrients) quality parameters.

Seismically triggered landslides are a major hazard and have caused severe secondary losses. This problem is especially important in the seismic prone Mailuu-Suu catchment in Kyrgyzstan, as it hosts disproportionately sensitive active or legacy uranium sites with deposited radioactive extractive wastes. These sites show a quasi-continuous release of radioactive contamination into surface waters, and especially after natural hazards, a sudden and massive input of pollutants into the surface waters is expected. However, landslides of contaminated sediments into surface waters represent a substantial exposure pathway that has not been properly addressed in the existing river basin management to date. To fill this gap, satellite imagery was massively employed to extract topography and geometric information, and the seismic Scoops3D and the one-dimensional numerical model, Hydrologic Engineering Centre, River Analysis System (HEC-RAS), were chosen to simulate the landslide-induced mass transport of total suspended solids (TSS) and natural radionuclides (Pb-210 as a proxy for modeling purposes) within the Mailuu-Suu river networks under two earthquake and two hydrological scenarios. The results show that the seismically vulnerable areas dominated in the upstream areas, and the mass of landslides increased dramatically with the increase of earthquake levels. After the landslides, the concentrations of radionuclides increased suddenly and dramatically. The peak values decreased along the longitudinal gradient of river networks, with the concentration curves becoming flat and wide in the downstream sections, and the transport speed of radionuclides decreased along the river networks. The conclusions of this study are that landslides commonly release a significant amount of pollutants with a relatively fast transport along river networks. Improved quantitative understanding of waterborne pollution dispersion across national borders will contribute to better co-ordination between governments and regulatory authorities of riparian states and, consequently, to future prevention of transnational political conflicts that have flared up in the last two decades over alleged pollution of transboundary water bodies.

The importance and awareness of accurate online water quality measurements increase every year in the oil and gas sector, whether it is for reducing oil discharge, preparing produced water for reinjection, or improving operational performance. For online measurement techniques to yield valuable analytical information, an understanding of their outputs must be established. Produced water reinjection has gained increasing attention in the last decade, as it can minimize negative environmental impacts by reducing oil discharge and has the potential to extend the economic life of reservoirs. To increase the amount of produced water that can be reinjected, the water must be maintained at a sufficient quality to prevent unintended formation damage. This review paper thoroughly describes different water quality issues related to suspended solids that can occur in an injection water treatment system and how the issues are often interlinked. A case study of measuring the total suspended solids concentration of seawater sampled from the Danish sector of the North Sea has been carried out to effectively quantify water quality in an injection water treatment facility. Furthermore, numerous on- and in-line techniques have been evaluated as candidates for measuring suspended solids. The last part of the paper discusses considerations regarding future microscopy analyzers based on five promising online microscopy technologies.

Introduction: Expensive chemical tests are usually applied to control the efficiency of wastewater treatment plants. However, the cost of measuring these parameters is one of the challenges of the wastewater treatment plants. Using statistical methods has been evaluated for possibility of calculating expensive parameters by measuring the inexpensive parameters in this study. Materials and Methods: Initial sample number in this study was 87 cases that were collected from SBR effluent treatment plants of Yazd as a routine sampling for two years in March 2013 to March 2015. Total suspended solids (TSS) and turbidity parameters were defined as independent variables and twelve parameters including BOD5, COD, TKN, NH3+, NO3-, NO2-, TP, TH, Ca2+, Mn2+, alkalinity, and color were the dependent variables. Spearman test was used to investigate the significant relationship between independent and dependent variables. Linear regression analysis was used to determine the linear equation between TSS and turbidity as independent variables with BOD5, COD, TKN, NH3-, NO2-, TP and color as dependent variables. Results: The results of the regression equations in relation to turbidity and TSS with independent variables showed that the R value for color, TKN, NH3+, BOD5, COD, TP, and NO2- were 0.942 , 0.931 , 0.91 , 0.905 , 0.874 , 0. 872 and 0.86 respectively from the highest to the lowest. Conclusion: The measured values of BOD5, COD, TKN, TP, NO2-, NH3+, and color in laboratory were very close to those predicted through regression equations. Therefore, regression equations created in this study can be used to calculate expensive parameters.

Sedimentation is one of the most popular wastewater treatment processes, and is used to separate solid particles from carrier fluid in settling tanks known as clarifiers. The clarifier, as the last major facility in wastewater treatment plants (WWTPs), can limit or define the performance of the overall WWTP. This paper presents a novel three-dimensional unsteady computational fluid dynamics (CFD) model to improve the efficiency of an industrial clarifier that had been experiencing underperformance and reduction in wastewater handling capacity. We propose a numerical technique to address the transient process of removing sludge from the floor of clarifiers by using rotating rakes. The CFD model was first applied to analyzing the ramifications of the current clarifier geometry on performance. The results show that the root causes for underperformance are related to the unconventional top side feed design of the clarifier, which leads to significant asymmetry in the flow distribution. The CFD model was next used to investigate various design modifications with the goal of improving the clarifier performance. A few geometry modification ideas such as an inward baffle, dissipating inlets, and a submerged skirt were found to create a more uniform flow distribution in the clarifier, significantly reducing the backflow into the feedwell and the velocity of the flow exiting the feedwell, which helps the solid particles to settle in the clarifier. These three designs were found to reduce the effluent total suspended solids (TSS) by more than 80% and thus significantly improve clarifier performance. It is believed that the CFD model developed in this study can become a computationally efficient tool for investigating the performance of industrial clarifiers with complex geometries and rotating rakes.

Validation is an essential process to evaluate the quality of waterbody remote sensing products, and the reliability and effective application of the in situ data of waterbody parameters are an important part of validation. Based on the in situ data of chlorophyll-a (Chl-a), total suspended solids (TSS) and other environmental variables (EVs) measured at the fixed station in Taihu Lake, we attempt to develop a prediction model to determine whether the in situ measurement has enough representativeness for validating waterbody remote sensing products. Key EVs that affect the changes of Chl-a and TSS are firstly identified by using correlation analysis, which participate in modeling as variables. In addition, three multi-parameter modeling approaches are selected to simulate the daily changes of Chl-a and TSS under different EVs configurations. The results indicate that the highest prediction accuracy can be achieved through the generalized regression neural network (GRNN) based model. In the all-valid dataset, the testing absolute average relative errors (AEs) of GRNN-based Chl-a and TSS prediction model are 11.4% and 11.3%, respectively, and in the sunny-day dataset, the testing AEs are 8.6% and 8.2%, respectively. Meanwhile, the application example proves that the prediction model in this paper can be effectively used to screen the in situ data and determine the time window for satellite-ground data matching.