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In this study, four water quality parameters were reviewed at 14 stations of river Ganga in pre-, during and post-lockdown and these parameters were modeled by using different machine learning algorithms. Various mathematical models were used for the computation of water quality parameters in pre-, during and post- lockdown period by using Central Pollution Control Board real-time data. Lockdown resulted in the reduction of Biochemical Oxygen Demand ranging from 55 to 92% with increased concentration of dissolved oxygen at few stations. pH was in range of 6.5-8.5 of during lockdown. Total coliform count declined during lockdown period at some stations. The modeling of oxygen saturation deficit showed supremacy of Thomas Mueller model (R 2 = 0.75) during lockdown over Streeter Phelps (R 2 = 0.57). Polynomial regression and Newton's Divided Difference model predicted possible values of water quality parameters till 30th June, 2020 and 07th August, 2020, respectively. It was found that predicted and real values were close to each other. Genetic algorithm was used to optimize hyperparameters of algorithms like Support Vector Regression and Radical Basis Function Neural Network, which were then employed for prediction of all examined water quality metrics. Computed values from ANN model were found close to the experimental ones (R 2 = 1). Support Vector Regression-Genetic Algorithm Hybrid proved to be very effective for accurate prediction of pH, Biochemical Oxygen Demand, Dissolved Oxygen and Total coliform count during lockdown. Supplementary Information: The online version contains supplementary material available at 10.1007/s13762-022-04423-1.
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Conventional enzyme-based continuous glucose sensors in interstitial fluid usually rely on dissolved oxygen as the electron-transfer mediator to bring electrons from oxidase to electrode while generating hydrogen peroxide. This may lead to several problems. First, the sensor may provide biased detection results owing to fluctuation of oxygen in interstitial fluid. Second, the polymer coatings that regulate the glucose/oxygen ratio can affect the dynamic response of the sensor. Third, the glucose oxidation reaction continuously produces corrosive hydrogen peroxide, which may compromise the long-term stability of the sensor. Here, we introduce an oxygen-independent nonenzymatic glucose sensor based on water splitting-assisted electrocatalysis for continuous glucose monitoring. For the water splitting reaction (i.e., hydrogen evolution reaction), a negative pretreatment potential is applied to produce a localized alkaline condition at the surface of the working electrode for subsequent nonenzymatic electrocatalytic oxidation of glucose. The reaction process does not require the participation of oxygen;therefore, the problems caused by oxygen can be avoided. The nonenzymatic sensor exhibits acceptable sensitivity, reliability, and biocompatibility for continuous glucose monitoring in hypoxic environments, as shown by the in vitro and in vivo measurements. Therefore, we believe that it is a promising technique for continuous glucose monitoring, especially for clinically hypoxic patients.
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The design principles of decentralised wastewater treatment systems (DEWATS) make them a practical sanitation option for municipalities to adopt in fast-growing cities in South Africa. Since 2014, a demonstration-scale DEWATS with a modular design consisting of a settler, anaerobic baffled reactor (ABR), anaerobic filter (AF), vertical down-flow constructed wetland (VFCW) and horizontal flow constructed wetland (HFCW) has been in operation in eThekwini. A performance evaluation after the long-term operation was undertaken in 2019 by comparing the final effluent with national regulatory requirements. Despite limitations in characterising the raw wastewater, a comparison of the settler and final effluent quality indicated high (≥ 85%) removal efficiencies of total chemical oxygen demand (CODt), ammonium-N (NH4-N) and orthophosphate-P (PO4-P), 75% removal of total suspended solids (TSS) and 83.3% log10 removal of Escherichia coli. Lack of exogenous and endogenous carbon and high dissolved oxygen (DO) concentrations (> 0.5 mg·L−1) inhibited denitrification in the HFCW, resulting in 12.5% of the effluent samples achieving compliance for nitrate-N (NO3-N). Moreover, mixed aggregate media and low residence times in the HFCW may have also contributed to poor NO3-N removal. During the COVID-19 lockdown, an unexpected shutdown and subsequent resumption of flow to the DEWATS indicated a 16-week recovery time based on achieving full nitrification in the HFCW. Although design modifications are necessary for the HFCW, the installation of urine diversion flushing toilets at the household level will reduce the nutrient loading to the DEWATS and potentially achieve fully compliant effluent. Alternatively, the application of two-stage vertical flow constructed wetlands to improve denitrification should also be explored in the South African context. With an improved design, DEWATS has the potential to fill the gap in both urban and rural sanitation in South Africa, where waterborne sanitation is still desired but connections to conventional wastewater treatment works (WWTWs) are not possible. © The Author(s) Published under a Creative Commons Attribution 4.0 International Licence (CC BY 4.0).
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The city-wide lockdown management was implemented in Shanghai from the end of March to the beginning of June in response to the prevention and control of COVID-19 epidemic. The sudden change of the way of work, lifestyle and industrial structure in the megacity would inevitably influence the characteristics of wastewater production, the composition of wastewater, the influent conditions, and operations of wastewater treatment plants（WWTPs）. The main countermeasures of operation in typical WWTPs were analyzed, which could provide a reference for early-warning and precaution when similar situations occur in WWTPs in the future. In order to eliminate the interference caused by the hysteresis effect after the rain stops in the combined drainage system, the corresponding relationship between the rainfall conditions and the influent quantity and quality of WWTPs was studied.The new statistical standard was established for distinguishing"rainy days"or"count dry days". The contemporaneous data of WWTPs in Shanghai central area during dry season in the past three years was analyzed. It was found that the quantity and quality of the influent showed a reverse trend during Shanghai's city-wide lockdown period. The quantity of wastewater decreased by 6% in the corresponding period, and the concentration of COD and NH3-N decreased by 33% and 17%, respectively. The addition of a large amount of chlorine-containing disinfectants led to an increase in the concentration of residual chlorine in the influent of some WWTPs. Based on the analysis of treatment process and design parameters of the existing WWTPs, the operation mode of exploiting potentialities was finally adopted.WWTPs operated stably and the effluent quality could meet the discharge standards through measures such as strengthening pretreatment, prolonging sludge retention time, controlling the concentration of dissolved oxygen in the biological reaction section, and increasing the dosage of phosphorus removal agents.
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While Rwanda is aiming at environmental pollution resilience and green growth, some industries are still discharging untreated effluent into the environment. This study gives a general overview of the compliance level of industrial effluent discharge in Rwanda and the linked negative environmental impacts. It comprises qualitative and quantitative analyses of data obtained from wastewater samples collected from five selected industries in Rwanda. The selected industries had previously been audited and monitored by the Rwanda Environment Management Authority (REMA), due to complains from neighboring residents. The study found that the effluent discharge from wastewater treatment plants (WWTP) for all concerned industries failed to comply with (i) oil and grease (O&G) national and international tolerable parameter limits or the (ii) fecal coliforms national standard. In addition, a compliance level of 66.7% was observed for key water quality monitoring parameters (pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and heavy metals (i.e., lead (Pb), cadmium (Cd), and chromium (Cr)). Following these study findings, one industry was closed by the REMA for deliberately discharging untreated effluent into an adjacent river. This study recommends the adoption of the best available technology for effluent treatment, installation or renovation of existing WWTPs, and the relocation to industrial zones of industries adjacent to fragile environments.
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Due to the pandemic caused by SARS-CoV-2 (severe acute respiratory syndrome corona virus 2) commonly known as COVID-19, a nationwide lockdown came into effect in India from 24th March midnight, 2020, which slowed down the movement of vehicles, operation of industries etc. Due to this reason a drastic change in the environment occurred and it caused the reduction of pollution level in the environment. The study mainly focuses on the positive impacts of lockdown in India. Studies have shown that after the implementation of lockdown, the level of the various major air pollution constituents of such as particulate matter (PM2.5, PM10, etc.), NO2, CO and ozone etc. in the air has reduced substantially. The air quality index data have clearly shown the difference in the level of air pollution between the year 2019 and 2020. The study was mainly focused on the comparison of air quality parameters such as particulate matter, NO2, CO and ozone etc. as well as the water pollution parameters such as Biochemical oxygen demand (BOD), chemical oxygen demand (COD) and dissolved oxygen (DO) for the River Yamuna and it was observed that there was substantial amount of positive change in pollutants after lockdown compared to what was before lockdown. The observations are carried out in atime frame manner such as before lockdown and after lockdown and results have been found with a huge difference in reduction of air pollution as well as water pollution.
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A comparative assessment of dissolved oxygen (DO) and biochemical oxygen demand (BOD) of river Ganga during prelockdown and lockdown periods was made through analysis of data generated from real-time water quality motoring systems. The concentration data for DO and BOD are examined for (i) prelockdown period (March 15-21, 2020) and (ii) lockdown period (March 22-April 15, 2020). The analysis results show 3%-20% decrease in DO concentration. The slight decrease in DO observed at all locations during the first week after lockdown which may be due to the increased levels of suspended solids and turbidity in the river water because of heavy rains. DO during fourth week of lockdown has shown a decreased value as compared to the prelockdown period at most of the locations. However, in West Bengal the DO has increased in lockdown. BOD value ranged between 1.13 mg/L and 5.56 mg/L during lockdown period, more or less similar to prelockdown range of 1.37-5.58 mg/L. This chapter further discusses the cause of water quality changes during the period of lockdown as compare to prelockdown period. © 2021 Elsevier Inc.
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Overall lockdown limitations toward the start of the year 2020 are credited to the annihilation and fatalities worldwide because of COVID-19. Most of the nations revealed rapid growth of COVID-19 cases and subsequently declared lockdown in several stages. Because of these lockdowns, industries had to stop producing goods other than the actual merchandise needed to survive. The air quality and natural water quality witnessed a noticeable improvement from limited human activity. This paper presents an investigation demonstrating this improvement under various lockdown periods, specifically for the Indian subcontinent. The rivers and atmosphere of Indian settings have been utilized here as a contextual analysis associated with industrial pollution. This work aims to study the associations and interrelationships between lockdowns during COVID-19 and their effect on air and water quality. The paper presents then and now an analysis of the Indian atmosphere based on various particulate matters and river health based on the biological oxygen demand, chemical oxygen demand, and dissolved oxygen. The study indicated a significant dip in air and water pollution levels and a significant improvement in the atmosphere and rivers’ quality during this period. Significant water bodies witnessed the pH level of 7.5 amidst lockdown, which is a good indicator of improved water health since the pH level of drinkable water is 7. The analysis carried out in this paper can also be mapped to other countries and landscapes of the world.
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At a low COD:TN ratio (≤5) in influent, maintaining a longer HRT (≥9 h) and longer SRT (≥30 d) are suggested to improve higher N removal efficiency in case of operation at low DO (Dissolved oxygen) level (0.9 ± 0.2 mg-O2/L). However, in case of operation at high DO level (4.0 ± 0.5 mg-O2/L), short HRT (1 h) and typical SRT (17 d) make it possible to achieve nitrogen removal. On the other hand, at a high COD:TN ratio (≥8.4), a typical HRT (9–15 h), SRT (12–19 d), and DO level (1.3–2.6 mg-O2/L) would be applied. Microbial distribution analysis showed an abundance of AOA (Ammonia-oxidizing archaea) under conditions of low DO (≤0.9 mg-O2/L). Nitrosomonas sp. are mostly found in the all investigated water resource recovery facilities (WRRFs). Nitrosospira sp. are only found under operating conditions of longer SRT for WRRFs with a low COD:TN ratio. In comparison between abundances of Nitrobacter sp. and Nitrospira sp., abundances of Nitrobacter sp. are proportional to low DO concentration rather than abundance of Nitrospira sp. A predominance of nosZ-type denitrifiers were found at low DO level. Abundance of denitrifiers by using nirS genes showed an over-abundance of denitrifiers by using nirK genes at low and high COD:TN ratios.
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The physicochemical parameters and ichthyofauna diversity of the water of the internationally important river Tangon at the Radhikapur village in Uttar Dinajpur district of West Bengal were studied for one year from December 2019 to November 2020. The study was done monthly from the four selected sampling sites of the Tangon river. Water temperature varied from 16.80..C to 32.60..C at all the sites during the study. pH ranged from 7.0 to 8.5, indicating the slightly alkaline nature of the water. Higher values of electrical conductivity were observed in the summer months. Free CO2 showed a positive correlation with water temperature and total hardness during the entire study. The lowest value of dissolved oxygen was observed to be 1.80 mgL-1 at Site 1 and Site 2, which might be due to the use of fertilizer at the nearby agricultural field and lifting of excessive sand from the Tangon river. The sudden increase in dissolved oxygen concentrations at all the sites from March to June might be due to the lesser anthropogenic activities during the lockdown in India because of the Covid-19 Pandemic situation. Total hardness (57.40 mgL-1 to 125.00 mgL-1) had a significant negative correlation with transparency at Site 2. Chloride (3.00 mgL-1 to 24.14 mgL-1) had a significant correlation with pH and total hardness at Site 1. BOD was varied between 1.00 mgL-1 and 11.04 mg L-1. The highest BOD was found in December at Site 4, which was much greater than the drinking and bathing water standard set by CPCB. It may be due to the higher level of pollution due to the increasing level of anthropogenic activities. The study on ichthyofauna diversity revealed a total of 40 species of fish belonged to seventeen families from the different sites of the Tangon river during the entire study period. Cyprinidae was found to be the most dominant family throughout the study period. Eight species of fishes were under the vulnerable category (20%) and three species were under a near threatened category (7%). The present study will help formulating the future policy for conservation and proper management of the fish diversity in the Radhikapur village of the Tangon river. Public awareness is very much important for the conservation of the river.
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Urbanization and anthropogenic activities are impacting the biodiversity of the water stream. Consequently, it interrupts water supply for daily purpose and sanitization requirement during pandemic Covid19. Water quality monitoring program designed to control water pollution. Development of IoT contributed to environment conservation including monitoring purpose for support decision system. This paper aims to study the integration of LoRa network with automatic water quality monitoring system. The proposed prototype of the system built with one gateway as base station and wireless sensor nodes (WSN) that embedded with water quality sensor of pH, turbidity, total dissolved solid (TDS), dissolved oxygen (DO) and temperature. The daily water quality status can be viewed in developed mobile application dashboard. Result shows that LoRa capabilities were affected from non-line of sight condition, transmission power and Spread Factor (SF) value. In conclusion, LoRa is compatible to be integrated with water quality monitoring system in urban environment. © 2021 IEEE.
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The recovery from the COVID-19 pandemic hit shows the emergence of increase in quality of life across various parts of the world. With this lifestyle change, people are looking towards high quality food. Fish being a major source of protein, the industry producing fish from aquaculture is booming. The proposed smart aerator system provides an integrated array of underwater systems for selective aeration of the water body. The smart system ensures targeted aeration to guarantee optimal levels of dissolved oxygen at all times. This is beneficial for perfect survival, growth, and reproduction of fishes. The strategically placed spider aerators are turned on when readings from the dissolved oxygen level at the location is below the optimum range of values. The air blower system consists of an intelligent switching system to activate the right aerator based on the requirement. The sensor data is relayed to the cloud with a wireless communication module. This data can be used for useful insights and all-round monitoring of the water body. The respective aerators have IR sensor to detect movement alongside on-board LEDs to indicate functioning status. Overall, this ensures maximum accelerated growth of healthy fishes. Thus, the solution aims at efficiently boosting the ability of the aquaculture industry to meet the ever-growing demand of consumers. © 2022 Institute of Physics Publishing. All rights reserved.
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This study utilized MIKE 11 to quantify the spatio-temporal dynamics of water quality parameters (Biochemical Oxygen Demand (BOD5), Dissolved Oxygen (DO) and temperature) in the Long Xuyen Quadrangle area of the Vietnamese Mekong Delta. Calibrated for the year of 2019 and validated for the year of 2020, the developed model showed a significant agreement between the observed and simulated values of water quality parameters. Locations near to cage culture areas exhibited higher BOD5 values than sites close to pond/lagoon culture areas due to the effects of numerous point sources of pollution, including upstream wastewater and out-fluxes from residential and tourism activities in the surrounding areas, all of which had a direct impact on the quality of the surface water used for aquaculture. Moreover, as aquacultural effluents have intensified and dispersed over time, water quality in the surrounding water bodies has degraded. The findings suggest that the effective planning, assessment and management of rapidly expanding aquaculture sites should be improved, including more rigorous water quality monitoring, to ensure the long-term sustainable expansion and development of the aquacultural sector in the Long Xuyen Quadrangle in particular, and the Vietnamese Mekong Delta as a whole.
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The COVID-19 pandemic has become a planetary concern that affecting the sustenance of the human population all around the globe. The effective measured has been taken in Malaysia to control the virus transmission by limiting the human vitality which unsurprisingly propitious to the environment. A monitoring study was conducted to assess the water quality status of surface seawater along the Port Dickson coast based on the Malaysian Marine Water Quality Index (MMWQI) and Malaysian Marine Water Quality Standards (MMWQCS) with an interval period of a year (March 2020-March 2021). In situ, water quality parameters incorporate temperature, pH, salinity, conductivity, dissolved oxygen (DO), and total dissolved solids (TDS) were measured at 14 sampling sites to evaluate the biochemical characteristics of water. Surface water samples were collected from the same sites and transported back to Universiti Putra Malaysia for nitrate (NO3-), ammonia (NH3), phosphate (PO4), biochemical oxygen demands (BOD), fecal coliform (Escherichia coli), and total suspended solids (TSS) analyses. The MMWQI showed the status of surface water from the Port Dickson coast was classified as moderate quality (50.41 - 64.05) for both sampling events. However, there are some indexes that showed significant decreases (p< 0.05) in the latter year. The concentration of nutrient pollution such as phosphate, nitrates, ammonia, fecal coliform as well as oil and grease, was decreased by 11.12%, 77.39%, 82.4%, 90.26%, and 99.9% respectively. The water parameters namely TDS, pH, and BOD levels were significantly decreased by 1.77%, 20.73%, and 77.16%. Certain parameters listed in the MMWQS such as temperature, pH, ammonia, fecal coliform, oil and grease were classified as Class 1 in March 2021. These occurrences recorded were greatly influenced by the reduction of the substantial human activities around the recreational beach of Port Dickson followed by the declaration of Movement Control Order (MCO) in Malaysia.
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During the recent COVID-19 related quarantine period, anecdotal evidence emerged pointing to a rapid, sharp improvement in water quality in some localities. Here we present results from an analysis of the impacts of the COVID-19 quarantine period using two long-term coastal water quality datasets. These datasets rely on sampling that operates at appropriate timescales to quantify the influence of reduced human activity on coastal water quality and span coastal ecosystems ranging from low human influence to highly urbanized systems. We tested two hypotheses: 1) reduced tourism during the COVID-19 quarantine period would lead to improved coastal water quality, and 2) water quality improvements would scale to the level of human influence, meaning that highly urbanized or tourist-centric watersheds would see greater improvement than more rural watersheds. A localized reduction in fecal indicator bacteria was observed in four highly impacted regions of the Texas (USA) coast, but this pattern was not widespread. In less impacted regions, the signature of natural, decadal environmental variability (e.g., dissolved oxygen and turbidity) overwhelmed any potential signature of reduced human activity. Results from this study add to the growing body of literature on the environmental impacts of the COVID-19 quarantine period, and when considered with existing literature, emphasize that coastal water quality improvements appear to be ephemeral and reserved for the most severely affected (by human activity) systems. Furthermore, results show the importance of assessing COVID-19 signatures against long-term, decadal datasets that adequately reveal a system's natural variation.