The purpose of this paper is to present the preliminary literature findings of a research project.The main project is set out to identify,analyse and report on performance requirements,mechanisms and actions required ...The purpose of this paper is to present the preliminary literature findings of a research project.The main project is set out to identify,analyse and report on performance requirements,mechanisms and actions required to address the performance of construction related small and medium size enterprises(SMEs)that are providing services for state owned enterprises(SOEs)in South Africa.The need for the project arose from the view that the absence of performance evaluation mechanism leads to the poor management of the performance of organisations involved in most SOE supply chain.This inevitably led to none creation of expected value in the system.Through a related literature study,the findings that have emerged so far suggest that it is notable that the SMEs related programmes in SOEs have not address performance and relationship management within their supply chain strategy in explicit terms as there is less or no means to record,measure and enhance SME contributions.These SMEs also recognise the fact that when their performances are poor and/or good,there is no difference and/or feedback mechanism to record it.展开更多
Water footprint(WF)measures human appropriation of water resources for consumptive use of surface and ground water(blue WF)and soil water(green WF)and for assimilating polluted water(grey WF).Questions have been often...Water footprint(WF)measures human appropriation of water resources for consumptive use of surface and ground water(blue WF)and soil water(green WF)and for assimilating polluted water(grey WF).Questions have been often asked about the exact meaning behind the numbers from WF accounting.However,to date environmental sustainability of WF has never been assessed at the sub-national level over time.This study evaluated the environmental sustainability of blue,green and grey WF for China’s 31 mainland provinces in 2002,2007 and 2012,and identified the unsustainable hotspots.Overall,the total WF increased by 30%between 2002 and 2012.The growth can be attributed to the increase of grey WF because the green and blue WF showed only a slight rise.Among all provinces investigated in 2012,eleven showed unsustainable blue WF(sustainability index SI<0),which were mainly located in the North China Plain.There were 12 provinces that displayed unsustainable green WF,and they were distributed in China’s southern and southeastern areas.The grey WF was not sustainable in approximately two third of provinces(19),which were mainly located in China’s middle and northern regions and Guangdong province.More than half of China’s provinces showed trends of improved SI of green and blue WF from 2002 to 2012.However,the SI of grey WF decreased in almost two third of provinces.Poor levels of WF sustainability were due to water scarcity and pollution,which intensify the degradation of local rivers and ecosystems and make restoration more difficult.The results shed light on the policy making needed to improve sustainable water management,and ecological restoration of hotspot regions.展开更多
This study explores the intricate relationship between population growth and water resource management in Louisiana, emphasizing the spatial distribution of water quality. Human activities, particularly urbanization, ...This study explores the intricate relationship between population growth and water resource management in Louisiana, emphasizing the spatial distribution of water quality. Human activities, particularly urbanization, have significantly impacted the state’s water resources, with population growth driving increased water withdrawals for public supply, industry, and power generation. By employing a Geographic Information System (GIS)-centered approach, this research utilizes Louisiana’s census data from 1999 to 2020 to illustrate population shifts and their effects on water resource distribution. The study also incorporated advanced remote sensing techniques, using Sentinel 2 imagery to assess the water quality through the Trophic State Index (TSI). The TSI, calculated based on the near-infrared (NIR) and Red bands of Sentinel-2 imagery, provided a nuanced understanding of the nutrient levels and clarity/ quality of water bodies across the state. The study reveals a significant correlation between population density and water withdrawals, with higher populations leading to greater extraction from both groundwater and surface water sources. For instance, densely populated parishes like East Baton Rouge and Orleans showed substantially higher water withdrawals for public supply, industry, and power generation compared to less populated areas. The water quality analysis indicated that many water bodies in Louisiana are experiencing high levels of nutrient enrichment, with rivers and streams accounting for 86% of the impaired water bodies, and lakes, reservoirs, and coastal waters showing hypereutrophic conditions in up to 96% of cases. These results underscore the significant impact of human activities on Louisiana’s water resources, highlighting the need for effective water management practices that consider both quantity and quality. The study therefore advocates for the implementation of water conservation measures, responsible consumption, and pollution prevention strategies to ensure the sustainable use of water resources and the preservation of water quality across Louisiana.展开更多
While various prior studies have delved into the potential consequences of climate change on crop production in specific areas, notably in southeastern Louisiana, limited investigation has been carried out concerning ...While various prior studies have delved into the potential consequences of climate change on crop production in specific areas, notably in southeastern Louisiana, limited investigation has been carried out concerning some crops within the state of Louisiana. Consequently, there exists a dearth of knowledge regarding the specific hurdles and potential benefits confronting agricultural producers in this region. Therefore, the primary aim of this study was to explore and measure the impact of climate change on the yields of corn, rice, soybeans, and cotton in Louisiana, thereby addressing this informational void. The study uses data on average high temperatures and precipitation to assess the impact of climate change on these specific food crops in Louisiana. The researchers used ArcGIS and its symbology tool to create three separate maps depicting the spatial distribution of harvested cropland in Louisiana. The graduated color option was used on each map, which represented the years 2007, 2012, and 2017. Similarly, eight separate maps were created using the graduated color option to visually present the distribution patterns of Louisiana’s corn, cotton, rice, and soybean crops. These maps provided a visual representation of the state’s total crop production between 2007 and 2017. The researchers also created six bar charts to show the distribution of corn, cotton, rice, and soybean production in Louisiana over three time periods: 2007, 2012, and 2017. These charts also included information about the average high temperature and annual precipitation in each parish. The study revealed decreasing trends in Louisiana corn and cotton yields alongside consistent increases in rice and soybean yields, with projections suggesting future temperature rises may negatively impact crop yields, highlighting the need for research into climate-smart agricultural practices to mitigate these effects and safeguard global crop production. Louisiana’s response to climate change in food crop production involves implementing a comprehensive Climate-Resilient Agriculture Program, focusing on developing climate-adaptive crop varieties, sustainable water management, climate-responsive insurance, farmer education, and outreach to safeguard food security, enhance agricultural resilience, and ensure sustainable crop production.展开更多
Louisiana possesses a bountiful groundwater reserve, an invaluable and noteworthy asset. Despite extensive literature on climate change implications in Louisiana, there is limited academic research focused on its effe...Louisiana possesses a bountiful groundwater reserve, an invaluable and noteworthy asset. Despite extensive literature on climate change implications in Louisiana, there is limited academic research focused on its effects on the state’s water resources. Therefore, this study addresses that gap by using GIS to spatially analyze water usage trends from 1960 to 2014, to examine climate-induced consequences and determine the susceptibility of water utilities’ functions and facilities. This study utilized various online sources to gather data on water withdrawals, temperature trends, and climate impacts in Louisiana. Water usage data from the Lower Mississippi Gulf-Water Science Centre and temperature trends from Meteoblue covering 2023 were also analyzed to assess the state’s water resource challenges. The water withdrawal data was linked to a shapefile within ArcMap, using graduated color symbology to visualize regional variations in water usage. This method highlighted significant water withdrawals across Louisiana from 1960 to 2014, clearly illustrating the differences between regions. Based on the data sources, the results show that groundwater levels in Louisiana have steadily declined over time. For instance, water levels in the Jasper Aquifer in St. Tammany dropped from approximately 125 feet to 50 feet, while levels in the Sparta Aquifer in Lincoln fell from 30 feet to −25 feet. Similarly, the Chicot Aquifer in Acadia experienced a decline from −25 feet to −50 feet. These reductions indicate a concerning trend of groundwater depletion, exacerbated by high temperatures and current drought conditions affecting roughly 73% of the state. To ensure sustainable water management in Louisiana, investing in water storage, transfer infrastructure, and conservation practices are needed to protect surface and groundwater sources. More so, the state’s Reservoir Priority and Development Program (RPDP), which includes the construction of reservoirs, is a key initiative that can address water scarcity, improve water supply, and enhance long-term water security.展开更多
The construction industry, known for its low productivity, is increasingly utilising software and mobile apps to enhance efficiency. However, more comprehensive research is needed to understand the effectiveness of th...The construction industry, known for its low productivity, is increasingly utilising software and mobile apps to enhance efficiency. However, more comprehensive research is needed to understand the effectiveness of these technology applications. The PRISMA principles utilised a scoping review methodology to ascertain pertinent studies and extract significant findings. From 2013 onwards, articles containing data on mobile applications or software designed to enhance productivity in the construction sector were obtained from multiple databases, including Emerald Insight, Science Direct, IEEE Xplore, and Google Scholar. After evaluating 2604 articles, 30 were determined to be pertinent to the study and were subsequently analysed for the review. The review identified five key themes: effectiveness, benefits, successful implementation examples, obstacles and limitations, and a comprehensive list of software and mobile apps. In addition, 71 software and mobile apps have shown potentially how these technologies can improve communication, collaboration, project management, real-time collaboration, document management, and on-the-go project information and estimating processes in the construction industry, increasing efficiency and productivity. The findings highlight the potential of these technologies such as Automation, Radio-Frequency Identification (RFID), Building Information Modeling (BIM), Augmented Reality (AR), Virtual Reality (VR), and Internet of Things (IoT) to improve efficiency and communication in the construction industry. Despite challenges such as cost, lack of awareness, resistance to change, compatibility concerns, human resources, technological and security concerns and licensing issues, the study identifies specific mobile applications and software with the potential to enhance efficiency significantly, improve productivity and streamline workflows. The broader societal impacts of construction software and mobile app development include increased efficiency, job creation, and sustainability.展开更多
Occupational health and safety continues to be a major component of the built environment. The study investigates the effectiveness of occupational health and safety laws and regulations in the construction industry i...Occupational health and safety continues to be a major component of the built environment. The study investigates the effectiveness of occupational health and safety laws and regulations in the construction industry in Ghana and identifies the influencing factors. Face-to-face interviews were conducted among 49 stakeholders from four relevant groups—regulatory institutions, consultants, contractors, artisans and labourers. The findings of the study suggest that the existing occupational health and safety legal and regulatory framework is barely effective. Stakeholders were aware of the existence of some laws and regulations but mostly could not identify the specific laws and their relevant contents. Consequently, compliance is found to be irregular. The key recurring factors affecting effectiveness of occupational health and safety laws and regulations include: negligence and lack of priority for occupational health and safety, lack of training, lack of funds for occupational health and safety, lack of capacity of regulatory and supervisory institutions, and lack of occupational health and safety education within construction firms. The findings of the study are foundational in strategic interventions aimed at improving compliance with occupational health and safety laws and regulations in the construction industry of Ghana.展开更多
This study aims to evaluate the performance of the individual Regional Climate Models (RCMs) used in Coordinated Regional Climate Downscaling Experiment (CORDEX) and the ensemble average of the four RCMs to feign the ...This study aims to evaluate the performance of the individual Regional Climate Models (RCMs) used in Coordinated Regional Climate Downscaling Experiment (CORDEX) and the ensemble average of the four RCMs to feign the characteristics of the rainfall pattern for the Mbarali River catchment in Rufiji Basin for the period of 1979 to 2005. Statistical analysis for model performance such as Root mean square error, Mean error, Pearson correlation coefficient, Mean, Median, standard deviation and trend analysis are used. In addition to the statistical measure of model performance, the models are tested on their ability to capture the observed annual cycles and interannual variability of rainfall. Results indicated that the RCMs from the CORDEX indicated a better performance to reproduce the rainfall characteristics over Mbarali River catchment in Rufiji Basin. They reproduced fairly the Era Interim annual cycle and inter-annual variability of rainfall. The ensemble average performed better than individual models in representing rainfall over Mbarali River catchment in Rufiji Basin. These suggest that rainfall simulation from the ensemble average will be used for the assessment of the hydrological impact studies over Mbarali River catchment in Rufiji Basin.展开更多
Various traffic management strategies have been developed to alleviate the congestion on freeways. The equity issue has been considered as one of the major challenges for the implementation of some traffic control str...Various traffic management strategies have been developed to alleviate the congestion on freeways. The equity issue has been considered as one of the major challenges for the implementation of some traffic control strategies, especially ramp metering. This paper presents a comparative evaluation of the efficiency and equity performance of a traffic control strategies namely Fixed Time Ramp Metering (FTRM). Instead of focusing on a single equity measure and/or indicator, different approaches to the equity concept are discussed and various equity measures are examined. The equity and efficiency performance of traffic control strategies are compared and evaluated by incorporating them into the simulated corridor. The Bosporus Bridge of Istanbul O-1 Freeway, Turkey is used as a test-bed for the simulation model and the control strategy is employed through microscopic traffic flow simulation software, VISSIM AG. The findings from the simulations show that the equity and efficiency properties of the network vary with the measures and indicators taken into account. The results also suggest that the trade-off between equity and efficiency can be observed for some measures, whereas regarding to other measures the trade-off is not validated.展开更多
Indoor air quality has a direct impact on human health. Indoor air quality has aroused great concern. This experimental study compares the effects of different water humidification on the indoor particulate pollution ...Indoor air quality has a direct impact on human health. Indoor air quality has aroused great concern. This experimental study compares the effects of different water humidification on the indoor particulate pollution characteristics, and analyzes the mass concentration and the particulate number concentration distribution of different sizes of particulates with time under each condition of the purified water humidification, the tap water humidification and the cold boiled water humidification in the office. The results show that under the three kinds of wetting conditions, the concentration of the fine particulates is higher. More minerals are contained in the tap water and the cold boiled water, so the two kinds of humidification have more significant impact on indoor particulate matter. But the purified water humidification has nearly no significant effect on it. The calcium and magnesium ionic compounds are partly removed after the water boiled, so the cold boiled water humidification has less impact on the indoor particulate matter than the tap water humidification. The mass concentration and particulate number concentration of the particle may also be affected due to the frequency of ultrasonic vibration.展开更多
In this paper, we modify the convective vorticity vector (CVV) defined as a cross product of absolute vorticity and gradient of equivalent potential temperature to moist potential vorticity vector (MPVV) defined as a ...In this paper, we modify the convective vorticity vector (CVV) defined as a cross product of absolute vorticity and gradient of equivalent potential temperature to moist potential vorticity vector (MPVV) defined as a cross product of absolute vorticity () and the gradient of the moist-air entropy potential temperature (). The patterns of (MPVV) are compared with the patterns of heavy rainfall events that occurred over different regions in Tanzania on 20<sup>th</sup> to 22<sup>nd</sup> December, 2011 and on 5<sup>th</sup> to 8<sup>th</sup> May, 2015. Moreover, the article aimed at assessing the relative contributions of the magnitude, horizontal and vertical components of (MPVV) detecting on the observed patterns of rainfall events. Dynamic and thermodynamic variables: wind speed, temperature, atmospheric pressure and relative humidity from numerical output generated by the Weather Research and Forecasting (WRF) model running at Tanzania Meteorological Agency (TMA) were used to compute MPVV. It is found that MPVV provide accurate tracking of locations received heavy rainfall, suggesting its potential use as a dynamic tracer for heavy rainfall events in Tanzania. Finally it is found that the first and second components of MPVV contribute almost equally in tracing locations received heavy rainfall events. The magnitude of MPVV described the locations received heavy rainfall events better than the components.展开更多
Intensification of agricultural land use and population growth from 1990-2017 has caused changes in land cover and land use of the Mbarali River sub-catchment which is located in the Upper Great Ruaha Sub basin, Tanza...Intensification of agricultural land use and population growth from 1990-2017 has caused changes in land cover and land use of the Mbarali River sub-catchment which is located in the Upper Great Ruaha Sub basin, Tanzania. This has affected the magnitude of the surface runoff, total water yield and the groundwater flow. This study assesses the impacts of the land cover and land use changes on the stream flows and hydrological water balance components (surface runoff, water yield, percolation and actual evapotranspiration). The land use and land cover (LULC) maps for three window period snapshots, 1990, 2006 and 2017 were created from Landsat TM and OLI_TIRS with the help of QGIS version 2.6. Supervised classification was used to generate LULC maps using the Maximum Likelihood Algorithm and Kappa statistics for assessment of accuracy. SWAT was set up and run to simulate stream flows and hydrological water balance components. The assessment of the impacts of land use and land cover changes on stream flows and hydrological water balance component was performed by comparing hydrological parameters simulated by SWAT using land use scenarios of 2006 and 2017 against the baseline land use scenario of 1990. Accuracy of LULC classification was good with Kappa statistics ranging between 0.9 and 0.99. There was a drastic increase in areal coverage of cultivated land, for periods 1990-2006 (5.84%) and 2006-2017 (12.05%) compared to other LULC. During 2006 and 2017 surface runoff increased by 4% and 9% respectively;however, water yield increased by only 0.5% compared to 1990 baseline period. This was attributed to increased proportion of cultivated land in the sub-catchment which has a high curve number (59.60) that indicates a higher runoff response and low infiltration rate.展开更多
In this study,the authors present Buoycrete,a new material and work method invented by the company Boskalis.Buoycrete is a light-weight concrete that is able to float and does not dissolve in water.Buoycrete is based ...In this study,the authors present Buoycrete,a new material and work method invented by the company Boskalis.Buoycrete is a light-weight concrete that is able to float and does not dissolve in water.Buoycrete is based on a unique combination of different materials.This paper will start with an overview of concrete structures in combination with fabrics and will present the structural behavior,construction methods and applications of Buoycrete.It demonstrates that Buoycrete combined with fabric formwork creates new possibilities for a broad kind of applications,for instance,the realization of façade elements,shell structures and civil engineering.展开更多
Urbanization, as a result of anthropogenic activities, reduces the vegetated and green spaces and thereby increases the impervious surfaces in cities. This in turn increases the surface temperature of cities when comp...Urbanization, as a result of anthropogenic activities, reduces the vegetated and green spaces and thereby increases the impervious surfaces in cities. This in turn increases the surface temperature of cities when compared to the rural regions resulting in the formation of urban heat island. Especially, in under-developed countries, it is very crucial to obtain timely and accurate information on the urban trend and its development due to the higher increasing rate of population growth and lack of infrastructural facilities and regulations to mitigate the adverse consequences of urbanization. The current study analyzes the urban development of Greater Accra, Ghana using Landsat 7 dataset acquired in 2002, 2013, and 2020. Further, the influence of urban growth on the land surface temperature (LST) and land cover variability (LCV) indices including NDVI (Normalized Difference Vegetation Index), NDBI (Normalized Difference Built-Up Index), and NDWI (Normalized Difference Water Index) is identified during the study periods. Results suggest that the area of built-up quadrupled between 2002 and 2020 in the study region. Shannon’s entropy-based analysis suggests that the urban development in the region is heterogeneous or dispersive in nature. Further, the regression analysis highlights a strong positive relation between LST and NDBI (0.755) and a negative relation is found associated between LST and NDVI (0.4417) and LST and NDWI (0.76). Results of the study could be useful to design sustainable urban socio-economic and environmental planning policies in the study region.展开更多
Agronomic practices such as transplanting age, plant spacing, and water application regimes in irrigated paddy production can have a significant impact towards the performance in rice growth and yield. A study was con...Agronomic practices such as transplanting age, plant spacing, and water application regimes in irrigated paddy production can have a significant impact towards the performance in rice growth and yield. A study was conducted to investigate the optimum transplanting age for maximum rice productivity under the systems of rice intensification (SRI) technology. The study treatments adopted were three representing 8, 12 and 15 days old seedlings replicated 3 times each. The experiment was set in randomized complete block design (RCBD) and transplanted at spacing 25 cm × 25 cm between rice hills. The rice variety tested was TXD 306 Super SARO, which was recommended by the ministry of Agriculture in Tanzania. Data was collected throughout the growing season in two mixed short rains and dry season of September 2013/2014 and September 2014/2015. Data collected included biomass at vegetative, flowering and harvesting stages, total number of tillers per hill, number of productive tillers per hill, number of grains per panicle and rice grain yield at the end of the season. Data was analyzed using SAS software version 9.1. The results suggested that transplanting at younger age of 8 to 12 days was recommended for Mkindo area in Mvomero Distirct, and other areas with similar soil conditions and agro ecological characteristics.展开更多
Optimum plant spacing is among key agronomic parameters that influence crop growth performance and crop yield. A study was conducted to investigate the optimum rice transplanting spacing under the Systems of Rice Inte...Optimum plant spacing is among key agronomic parameters that influence crop growth performance and crop yield. A study was conducted to investigate the optimum rice transplanting spacing under the Systems of Rice Intensification (SRI) practice in Tanzania. The study composed of five treatments of rice transplanting spacing namely 1) 15 cm × 15 cm (T1);2) 20 cm × 20 cm (T2);3) 25 cm × 25 cm (T3);4) 30 cm × 30 cm (T4);and 5) 35 cm × 35 cm (T5). The experiment was set in a Randomized Complete Block Design (RCBD) and transplanted with uniform age of 12 days old seedlings in all treatments. The rice variety tested was TXD 306 Super SARO which was recommended by the Ministry of Agriculture for flooded rice in central and eastern Tanzania. Data was collected throughout the two growing seasons (Masika and Vuli) of 2013 and 2014. Data collected include biomass at vegetative, flowering and harvesting stages, total number of tillers per hill, number of productive tillers per hill, number of grains per panicle and rice grain yield at the end of the season. Data was analyzed using SAS software version 9.1. Results have shown that transplanting spacing of 25 cm × 25 cm, 30 cm × 30 cm and 35 cm × 35 cm has significantly performed better than rice transplanted at 15 cm × 15 cm and 20 cm × 20 cm. For the higher performing treatments, 25 cm × 25 cm has performed much higher than the rest. It is therefore recommended that for rice variety TXD 306 Super SARO under SRI practice in areas with soil conditions similar to Mkindo area in Morogoro Region, the optimum transplanting spacing that gives maximum yield is 25 × 25 cm.展开更多
There are socio-technological challenges towards extension of the application of rainwater harvesting (RWH) practices in developing countries. An attempt to address this was done using the Mnyundo Primary School, Tanz...There are socio-technological challenges towards extension of the application of rainwater harvesting (RWH) practices in developing countries. An attempt to address this was done using the Mnyundo Primary School, Tanzania, as a study area for evaluating the technical, economic, and social challenges of RWH practices. A storage water level monitoring gauge was used so as to simplify rainwater quantity control and utilization strategy. Basic quality control components such as first flush tank were incorporated so as to reduce the particle load flowing into the storage. Cost reduction strategies such as the one (1) company one (1) community campaign were applied to address the cost implication. To enhance ownership, participatory approach of the beneficiaries in all stages including planning, designing and implementation was adopted. In order to ensure project sustainability, training on how to operate and maintain were provided as well as a maintenance manual to impart a sense of ownership. For the challenges of imparting RWH practices in Tanzania, 19 solutions have been identified and they include provision of RWH manuals, guidelines and regulations, government incentives, and promotion of self-financing initiatives. For developing countries, the study proposes the following strategies: establishing relevant regulations and research centers, enhancing individual and community financial stability, conducting demonstration projects, and increased investment by government on promotion.展开更多
There are significant household water supply challenges including quantity sufficiency and quality, which have economic and social implications. The challenges have remained despite the efforts of government establish...There are significant household water supply challenges including quantity sufficiency and quality, which have economic and social implications. The challenges have remained despite the efforts of government establishing centralized or groundwater systems, and/or having individual crude systems. A Tanzanian rural household case study was considered by assessing the performance of a currently relied surface runoff collecting pond system for domestic purposes. A daily water balance model was applied with performance parameters, no water days (NWD) and rainwater usage (RUR). Rooftop runoff harvesting system was proposed as a water supply source in addition to the current one. Under such dual supply conditions, users can meet the drinking and non-drinking demand even in dry seasons at a minimum of 2 and 20 L/person/d, respectively. For rainwater harvesting adoption (considering selected regions), it was further established that amount and variation in rainfall impacts on quantity available for meeting demand. Increased catchment implies increased harvestable quantity, and with same storage higher reduction of number of NWD although with slight decrease of RUR. Also, increased storage is required for achieving higher RUR in case the same demand is maintained. But same storage can be maintained for increased demand relative to catchment size. However, rainwater catchment increase has greater impact on meeting a specified demand under given condition of rainfall quantity and variation. The RWH technology strategies presented in this study are replicable in other developing countries under site specific conditions.展开更多
Nitrite in drinking water is a potential health hazard and monitoring its concentrations in distributed water is of paramount importance. When monochloramine is used in secondary disinfection in drinking water distrib...Nitrite in drinking water is a potential health hazard and monitoring its concentrations in distributed water is of paramount importance. When monochloramine is used in secondary disinfection in drinking water distribution systems (DWDSs), nitrite is often formed by nitrification in the biofilm on the inner surface of distribution pipes. This article attempts to identify areas with a risk of increased nitrite concentrations as well as the main reasons leading to nitrite occurrence in a large urban DWDS in Finland using spatial inspection of obligatory monitoring data. Nitrification was found to occur throughout the study area, though nitrite was not increased everywhere. Instead, nitrite was increased close to the water treatment plants (WTPs) and was connected to fresh drinking water than stagnant drinking water. Temperature effects on nitrite concentrations were surprisingly insignificant, even though it is well known that nitrification reactions are affected by temperature. The temperature dependence of ammonium and total residual chlorine was more significant than the dependence of nitrite. The findings of this study emphasize the need to monitor nitrite concentrations close to WTPs.展开更多
This study investigated coal-mine drainage(AMD)and municipal wastewater(MWW)contaminant concentrations and conducted the combined treatment in phases I and II:phase I,evaluating the effects of mixing the two based on ...This study investigated coal-mine drainage(AMD)and municipal wastewater(MWW)contaminant concentrations and conducted the combined treatment in phases I and II:phase I,evaluating the effects of mixing the two based on the extent of acid neutralization and metals removal;phase II:conducting anaerobic batch reactor treatment of AMD and MWW under varying COD/sulfate ratios(0.04-5.0).In phase I,acid mine drainage water quality conditions are as follows:pH 4.5,acidity 467.5 mg/L as CaCO3,alkalinity 96.0 mg/L as CaCO3,Cl-11.8 mg/L,SO42-1722 mg/L,TDS 2757.5 mg/L,TSS 9.8 mg/L,BOD 14.7 mg/L,Fe 138.1 mg/L,Mg 110.8 mg/L.Mn 7.5 mg/L,Al 8.1 mg/L,Na 114.2 mg/L,and Ca 233.5 mg/L.Results of the mixing experiments indicated significant removal of selected metals(Fe 85~98%,Mg 0~65%,Mn 63~89%,Al 98~99%,Na 0~30%),acidity(77~95%)from the mine water and pH was raised to above 6.3.The Phase II results suggested under the wide range of COD/sulfate ratios,COD and sulfate removal varied from 37.4%-100%and 0%-93.5%respectively.During biological treatment,alkalinity was generated which leads to pH increase to around 7.6-8.5.The results suggested feasibility of the proposed technology for co-treatment of AMD and MWW.A conceptual design of co-treatment system which is expected to remove a matrix of pollutants has been provided to utilize all the locally available water resources to achieve the optimum treatment efficiency.The technology also offers an opportunity to significantly reduce capital and operating costs compared to the existing treatment methodologies used.Featured Application:In this study,we have measured the concentrations of contaminants in acid mine drainage(AMD)and municipal wastewater(MWW)and conducted the combined treatment in phases I and II.This is significant because in previous years there was a massive fish kill that is linked to the high total dissolved solids(TDS)and salinity content in the water.With the current proposed combined treatment technology,it shows high potential in reducing TDS and salinity content in the combined wastewater which will prevent similar accident(Dunkard creek fish kill in 2019)happening again.展开更多
文摘The purpose of this paper is to present the preliminary literature findings of a research project.The main project is set out to identify,analyse and report on performance requirements,mechanisms and actions required to address the performance of construction related small and medium size enterprises(SMEs)that are providing services for state owned enterprises(SOEs)in South Africa.The need for the project arose from the view that the absence of performance evaluation mechanism leads to the poor management of the performance of organisations involved in most SOE supply chain.This inevitably led to none creation of expected value in the system.Through a related literature study,the findings that have emerged so far suggest that it is notable that the SMEs related programmes in SOEs have not address performance and relationship management within their supply chain strategy in explicit terms as there is less or no means to record,measure and enhance SME contributions.These SMEs also recognise the fact that when their performances are poor and/or good,there is no difference and/or feedback mechanism to record it.
基金supported by the National Natural Science Foundation of China(Grant No.41625001)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA20060402)+4 种基金the Pengcheng Scholar Program of Shenzhen,the National High-level Talents Special Support Plan(“Ten Thousand Talents Plan”)the Leading Innovative Talent Program for young and middle-aged scholars by the Ministry of Science and Technologysupported by the Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control(Grant No.2017B030301012)the State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Controlthe High-level Special Funding of the Southern University of Science and Technology(Grant No.G02296302,G02296402).
文摘Water footprint(WF)measures human appropriation of water resources for consumptive use of surface and ground water(blue WF)and soil water(green WF)and for assimilating polluted water(grey WF).Questions have been often asked about the exact meaning behind the numbers from WF accounting.However,to date environmental sustainability of WF has never been assessed at the sub-national level over time.This study evaluated the environmental sustainability of blue,green and grey WF for China’s 31 mainland provinces in 2002,2007 and 2012,and identified the unsustainable hotspots.Overall,the total WF increased by 30%between 2002 and 2012.The growth can be attributed to the increase of grey WF because the green and blue WF showed only a slight rise.Among all provinces investigated in 2012,eleven showed unsustainable blue WF(sustainability index SI<0),which were mainly located in the North China Plain.There were 12 provinces that displayed unsustainable green WF,and they were distributed in China’s southern and southeastern areas.The grey WF was not sustainable in approximately two third of provinces(19),which were mainly located in China’s middle and northern regions and Guangdong province.More than half of China’s provinces showed trends of improved SI of green and blue WF from 2002 to 2012.However,the SI of grey WF decreased in almost two third of provinces.Poor levels of WF sustainability were due to water scarcity and pollution,which intensify the degradation of local rivers and ecosystems and make restoration more difficult.The results shed light on the policy making needed to improve sustainable water management,and ecological restoration of hotspot regions.
文摘This study explores the intricate relationship between population growth and water resource management in Louisiana, emphasizing the spatial distribution of water quality. Human activities, particularly urbanization, have significantly impacted the state’s water resources, with population growth driving increased water withdrawals for public supply, industry, and power generation. By employing a Geographic Information System (GIS)-centered approach, this research utilizes Louisiana’s census data from 1999 to 2020 to illustrate population shifts and their effects on water resource distribution. The study also incorporated advanced remote sensing techniques, using Sentinel 2 imagery to assess the water quality through the Trophic State Index (TSI). The TSI, calculated based on the near-infrared (NIR) and Red bands of Sentinel-2 imagery, provided a nuanced understanding of the nutrient levels and clarity/ quality of water bodies across the state. The study reveals a significant correlation between population density and water withdrawals, with higher populations leading to greater extraction from both groundwater and surface water sources. For instance, densely populated parishes like East Baton Rouge and Orleans showed substantially higher water withdrawals for public supply, industry, and power generation compared to less populated areas. The water quality analysis indicated that many water bodies in Louisiana are experiencing high levels of nutrient enrichment, with rivers and streams accounting for 86% of the impaired water bodies, and lakes, reservoirs, and coastal waters showing hypereutrophic conditions in up to 96% of cases. These results underscore the significant impact of human activities on Louisiana’s water resources, highlighting the need for effective water management practices that consider both quantity and quality. The study therefore advocates for the implementation of water conservation measures, responsible consumption, and pollution prevention strategies to ensure the sustainable use of water resources and the preservation of water quality across Louisiana.
文摘While various prior studies have delved into the potential consequences of climate change on crop production in specific areas, notably in southeastern Louisiana, limited investigation has been carried out concerning some crops within the state of Louisiana. Consequently, there exists a dearth of knowledge regarding the specific hurdles and potential benefits confronting agricultural producers in this region. Therefore, the primary aim of this study was to explore and measure the impact of climate change on the yields of corn, rice, soybeans, and cotton in Louisiana, thereby addressing this informational void. The study uses data on average high temperatures and precipitation to assess the impact of climate change on these specific food crops in Louisiana. The researchers used ArcGIS and its symbology tool to create three separate maps depicting the spatial distribution of harvested cropland in Louisiana. The graduated color option was used on each map, which represented the years 2007, 2012, and 2017. Similarly, eight separate maps were created using the graduated color option to visually present the distribution patterns of Louisiana’s corn, cotton, rice, and soybean crops. These maps provided a visual representation of the state’s total crop production between 2007 and 2017. The researchers also created six bar charts to show the distribution of corn, cotton, rice, and soybean production in Louisiana over three time periods: 2007, 2012, and 2017. These charts also included information about the average high temperature and annual precipitation in each parish. The study revealed decreasing trends in Louisiana corn and cotton yields alongside consistent increases in rice and soybean yields, with projections suggesting future temperature rises may negatively impact crop yields, highlighting the need for research into climate-smart agricultural practices to mitigate these effects and safeguard global crop production. Louisiana’s response to climate change in food crop production involves implementing a comprehensive Climate-Resilient Agriculture Program, focusing on developing climate-adaptive crop varieties, sustainable water management, climate-responsive insurance, farmer education, and outreach to safeguard food security, enhance agricultural resilience, and ensure sustainable crop production.
文摘Louisiana possesses a bountiful groundwater reserve, an invaluable and noteworthy asset. Despite extensive literature on climate change implications in Louisiana, there is limited academic research focused on its effects on the state’s water resources. Therefore, this study addresses that gap by using GIS to spatially analyze water usage trends from 1960 to 2014, to examine climate-induced consequences and determine the susceptibility of water utilities’ functions and facilities. This study utilized various online sources to gather data on water withdrawals, temperature trends, and climate impacts in Louisiana. Water usage data from the Lower Mississippi Gulf-Water Science Centre and temperature trends from Meteoblue covering 2023 were also analyzed to assess the state’s water resource challenges. The water withdrawal data was linked to a shapefile within ArcMap, using graduated color symbology to visualize regional variations in water usage. This method highlighted significant water withdrawals across Louisiana from 1960 to 2014, clearly illustrating the differences between regions. Based on the data sources, the results show that groundwater levels in Louisiana have steadily declined over time. For instance, water levels in the Jasper Aquifer in St. Tammany dropped from approximately 125 feet to 50 feet, while levels in the Sparta Aquifer in Lincoln fell from 30 feet to −25 feet. Similarly, the Chicot Aquifer in Acadia experienced a decline from −25 feet to −50 feet. These reductions indicate a concerning trend of groundwater depletion, exacerbated by high temperatures and current drought conditions affecting roughly 73% of the state. To ensure sustainable water management in Louisiana, investing in water storage, transfer infrastructure, and conservation practices are needed to protect surface and groundwater sources. More so, the state’s Reservoir Priority and Development Program (RPDP), which includes the construction of reservoirs, is a key initiative that can address water scarcity, improve water supply, and enhance long-term water security.
文摘The construction industry, known for its low productivity, is increasingly utilising software and mobile apps to enhance efficiency. However, more comprehensive research is needed to understand the effectiveness of these technology applications. The PRISMA principles utilised a scoping review methodology to ascertain pertinent studies and extract significant findings. From 2013 onwards, articles containing data on mobile applications or software designed to enhance productivity in the construction sector were obtained from multiple databases, including Emerald Insight, Science Direct, IEEE Xplore, and Google Scholar. After evaluating 2604 articles, 30 were determined to be pertinent to the study and were subsequently analysed for the review. The review identified five key themes: effectiveness, benefits, successful implementation examples, obstacles and limitations, and a comprehensive list of software and mobile apps. In addition, 71 software and mobile apps have shown potentially how these technologies can improve communication, collaboration, project management, real-time collaboration, document management, and on-the-go project information and estimating processes in the construction industry, increasing efficiency and productivity. The findings highlight the potential of these technologies such as Automation, Radio-Frequency Identification (RFID), Building Information Modeling (BIM), Augmented Reality (AR), Virtual Reality (VR), and Internet of Things (IoT) to improve efficiency and communication in the construction industry. Despite challenges such as cost, lack of awareness, resistance to change, compatibility concerns, human resources, technological and security concerns and licensing issues, the study identifies specific mobile applications and software with the potential to enhance efficiency significantly, improve productivity and streamline workflows. The broader societal impacts of construction software and mobile app development include increased efficiency, job creation, and sustainability.
文摘Occupational health and safety continues to be a major component of the built environment. The study investigates the effectiveness of occupational health and safety laws and regulations in the construction industry in Ghana and identifies the influencing factors. Face-to-face interviews were conducted among 49 stakeholders from four relevant groups—regulatory institutions, consultants, contractors, artisans and labourers. The findings of the study suggest that the existing occupational health and safety legal and regulatory framework is barely effective. Stakeholders were aware of the existence of some laws and regulations but mostly could not identify the specific laws and their relevant contents. Consequently, compliance is found to be irregular. The key recurring factors affecting effectiveness of occupational health and safety laws and regulations include: negligence and lack of priority for occupational health and safety, lack of training, lack of funds for occupational health and safety, lack of capacity of regulatory and supervisory institutions, and lack of occupational health and safety education within construction firms. The findings of the study are foundational in strategic interventions aimed at improving compliance with occupational health and safety laws and regulations in the construction industry of Ghana.
文摘This study aims to evaluate the performance of the individual Regional Climate Models (RCMs) used in Coordinated Regional Climate Downscaling Experiment (CORDEX) and the ensemble average of the four RCMs to feign the characteristics of the rainfall pattern for the Mbarali River catchment in Rufiji Basin for the period of 1979 to 2005. Statistical analysis for model performance such as Root mean square error, Mean error, Pearson correlation coefficient, Mean, Median, standard deviation and trend analysis are used. In addition to the statistical measure of model performance, the models are tested on their ability to capture the observed annual cycles and interannual variability of rainfall. Results indicated that the RCMs from the CORDEX indicated a better performance to reproduce the rainfall characteristics over Mbarali River catchment in Rufiji Basin. They reproduced fairly the Era Interim annual cycle and inter-annual variability of rainfall. The ensemble average performed better than individual models in representing rainfall over Mbarali River catchment in Rufiji Basin. These suggest that rainfall simulation from the ensemble average will be used for the assessment of the hydrological impact studies over Mbarali River catchment in Rufiji Basin.
文摘Various traffic management strategies have been developed to alleviate the congestion on freeways. The equity issue has been considered as one of the major challenges for the implementation of some traffic control strategies, especially ramp metering. This paper presents a comparative evaluation of the efficiency and equity performance of a traffic control strategies namely Fixed Time Ramp Metering (FTRM). Instead of focusing on a single equity measure and/or indicator, different approaches to the equity concept are discussed and various equity measures are examined. The equity and efficiency performance of traffic control strategies are compared and evaluated by incorporating them into the simulated corridor. The Bosporus Bridge of Istanbul O-1 Freeway, Turkey is used as a test-bed for the simulation model and the control strategy is employed through microscopic traffic flow simulation software, VISSIM AG. The findings from the simulations show that the equity and efficiency properties of the network vary with the measures and indicators taken into account. The results also suggest that the trade-off between equity and efficiency can be observed for some measures, whereas regarding to other measures the trade-off is not validated.
文摘Indoor air quality has a direct impact on human health. Indoor air quality has aroused great concern. This experimental study compares the effects of different water humidification on the indoor particulate pollution characteristics, and analyzes the mass concentration and the particulate number concentration distribution of different sizes of particulates with time under each condition of the purified water humidification, the tap water humidification and the cold boiled water humidification in the office. The results show that under the three kinds of wetting conditions, the concentration of the fine particulates is higher. More minerals are contained in the tap water and the cold boiled water, so the two kinds of humidification have more significant impact on indoor particulate matter. But the purified water humidification has nearly no significant effect on it. The calcium and magnesium ionic compounds are partly removed after the water boiled, so the cold boiled water humidification has less impact on the indoor particulate matter than the tap water humidification. The mass concentration and particulate number concentration of the particle may also be affected due to the frequency of ultrasonic vibration.
文摘In this paper, we modify the convective vorticity vector (CVV) defined as a cross product of absolute vorticity and gradient of equivalent potential temperature to moist potential vorticity vector (MPVV) defined as a cross product of absolute vorticity () and the gradient of the moist-air entropy potential temperature (). The patterns of (MPVV) are compared with the patterns of heavy rainfall events that occurred over different regions in Tanzania on 20<sup>th</sup> to 22<sup>nd</sup> December, 2011 and on 5<sup>th</sup> to 8<sup>th</sup> May, 2015. Moreover, the article aimed at assessing the relative contributions of the magnitude, horizontal and vertical components of (MPVV) detecting on the observed patterns of rainfall events. Dynamic and thermodynamic variables: wind speed, temperature, atmospheric pressure and relative humidity from numerical output generated by the Weather Research and Forecasting (WRF) model running at Tanzania Meteorological Agency (TMA) were used to compute MPVV. It is found that MPVV provide accurate tracking of locations received heavy rainfall, suggesting its potential use as a dynamic tracer for heavy rainfall events in Tanzania. Finally it is found that the first and second components of MPVV contribute almost equally in tracing locations received heavy rainfall events. The magnitude of MPVV described the locations received heavy rainfall events better than the components.
文摘Intensification of agricultural land use and population growth from 1990-2017 has caused changes in land cover and land use of the Mbarali River sub-catchment which is located in the Upper Great Ruaha Sub basin, Tanzania. This has affected the magnitude of the surface runoff, total water yield and the groundwater flow. This study assesses the impacts of the land cover and land use changes on the stream flows and hydrological water balance components (surface runoff, water yield, percolation and actual evapotranspiration). The land use and land cover (LULC) maps for three window period snapshots, 1990, 2006 and 2017 were created from Landsat TM and OLI_TIRS with the help of QGIS version 2.6. Supervised classification was used to generate LULC maps using the Maximum Likelihood Algorithm and Kappa statistics for assessment of accuracy. SWAT was set up and run to simulate stream flows and hydrological water balance components. The assessment of the impacts of land use and land cover changes on stream flows and hydrological water balance component was performed by comparing hydrological parameters simulated by SWAT using land use scenarios of 2006 and 2017 against the baseline land use scenario of 1990. Accuracy of LULC classification was good with Kappa statistics ranging between 0.9 and 0.99. There was a drastic increase in areal coverage of cultivated land, for periods 1990-2006 (5.84%) and 2006-2017 (12.05%) compared to other LULC. During 2006 and 2017 surface runoff increased by 4% and 9% respectively;however, water yield increased by only 0.5% compared to 1990 baseline period. This was attributed to increased proportion of cultivated land in the sub-catchment which has a high curve number (59.60) that indicates a higher runoff response and low infiltration rate.
基金This research was done at the Baggermaatschappij Boskalis B.V.the Eindhoven University of Technology.
文摘In this study,the authors present Buoycrete,a new material and work method invented by the company Boskalis.Buoycrete is a light-weight concrete that is able to float and does not dissolve in water.Buoycrete is based on a unique combination of different materials.This paper will start with an overview of concrete structures in combination with fabrics and will present the structural behavior,construction methods and applications of Buoycrete.It demonstrates that Buoycrete combined with fabric formwork creates new possibilities for a broad kind of applications,for instance,the realization of façade elements,shell structures and civil engineering.
文摘Urbanization, as a result of anthropogenic activities, reduces the vegetated and green spaces and thereby increases the impervious surfaces in cities. This in turn increases the surface temperature of cities when compared to the rural regions resulting in the formation of urban heat island. Especially, in under-developed countries, it is very crucial to obtain timely and accurate information on the urban trend and its development due to the higher increasing rate of population growth and lack of infrastructural facilities and regulations to mitigate the adverse consequences of urbanization. The current study analyzes the urban development of Greater Accra, Ghana using Landsat 7 dataset acquired in 2002, 2013, and 2020. Further, the influence of urban growth on the land surface temperature (LST) and land cover variability (LCV) indices including NDVI (Normalized Difference Vegetation Index), NDBI (Normalized Difference Built-Up Index), and NDWI (Normalized Difference Water Index) is identified during the study periods. Results suggest that the area of built-up quadrupled between 2002 and 2020 in the study region. Shannon’s entropy-based analysis suggests that the urban development in the region is heterogeneous or dispersive in nature. Further, the regression analysis highlights a strong positive relation between LST and NDBI (0.755) and a negative relation is found associated between LST and NDVI (0.4417) and LST and NDWI (0.76). Results of the study could be useful to design sustainable urban socio-economic and environmental planning policies in the study region.
文摘Agronomic practices such as transplanting age, plant spacing, and water application regimes in irrigated paddy production can have a significant impact towards the performance in rice growth and yield. A study was conducted to investigate the optimum transplanting age for maximum rice productivity under the systems of rice intensification (SRI) technology. The study treatments adopted were three representing 8, 12 and 15 days old seedlings replicated 3 times each. The experiment was set in randomized complete block design (RCBD) and transplanted at spacing 25 cm × 25 cm between rice hills. The rice variety tested was TXD 306 Super SARO, which was recommended by the ministry of Agriculture in Tanzania. Data was collected throughout the growing season in two mixed short rains and dry season of September 2013/2014 and September 2014/2015. Data collected included biomass at vegetative, flowering and harvesting stages, total number of tillers per hill, number of productive tillers per hill, number of grains per panicle and rice grain yield at the end of the season. Data was analyzed using SAS software version 9.1. The results suggested that transplanting at younger age of 8 to 12 days was recommended for Mkindo area in Mvomero Distirct, and other areas with similar soil conditions and agro ecological characteristics.
文摘Optimum plant spacing is among key agronomic parameters that influence crop growth performance and crop yield. A study was conducted to investigate the optimum rice transplanting spacing under the Systems of Rice Intensification (SRI) practice in Tanzania. The study composed of five treatments of rice transplanting spacing namely 1) 15 cm × 15 cm (T1);2) 20 cm × 20 cm (T2);3) 25 cm × 25 cm (T3);4) 30 cm × 30 cm (T4);and 5) 35 cm × 35 cm (T5). The experiment was set in a Randomized Complete Block Design (RCBD) and transplanted with uniform age of 12 days old seedlings in all treatments. The rice variety tested was TXD 306 Super SARO which was recommended by the Ministry of Agriculture for flooded rice in central and eastern Tanzania. Data was collected throughout the two growing seasons (Masika and Vuli) of 2013 and 2014. Data collected include biomass at vegetative, flowering and harvesting stages, total number of tillers per hill, number of productive tillers per hill, number of grains per panicle and rice grain yield at the end of the season. Data was analyzed using SAS software version 9.1. Results have shown that transplanting spacing of 25 cm × 25 cm, 30 cm × 30 cm and 35 cm × 35 cm has significantly performed better than rice transplanted at 15 cm × 15 cm and 20 cm × 20 cm. For the higher performing treatments, 25 cm × 25 cm has performed much higher than the rest. It is therefore recommended that for rice variety TXD 306 Super SARO under SRI practice in areas with soil conditions similar to Mkindo area in Morogoro Region, the optimum transplanting spacing that gives maximum yield is 25 × 25 cm.
文摘There are socio-technological challenges towards extension of the application of rainwater harvesting (RWH) practices in developing countries. An attempt to address this was done using the Mnyundo Primary School, Tanzania, as a study area for evaluating the technical, economic, and social challenges of RWH practices. A storage water level monitoring gauge was used so as to simplify rainwater quantity control and utilization strategy. Basic quality control components such as first flush tank were incorporated so as to reduce the particle load flowing into the storage. Cost reduction strategies such as the one (1) company one (1) community campaign were applied to address the cost implication. To enhance ownership, participatory approach of the beneficiaries in all stages including planning, designing and implementation was adopted. In order to ensure project sustainability, training on how to operate and maintain were provided as well as a maintenance manual to impart a sense of ownership. For the challenges of imparting RWH practices in Tanzania, 19 solutions have been identified and they include provision of RWH manuals, guidelines and regulations, government incentives, and promotion of self-financing initiatives. For developing countries, the study proposes the following strategies: establishing relevant regulations and research centers, enhancing individual and community financial stability, conducting demonstration projects, and increased investment by government on promotion.
文摘There are significant household water supply challenges including quantity sufficiency and quality, which have economic and social implications. The challenges have remained despite the efforts of government establishing centralized or groundwater systems, and/or having individual crude systems. A Tanzanian rural household case study was considered by assessing the performance of a currently relied surface runoff collecting pond system for domestic purposes. A daily water balance model was applied with performance parameters, no water days (NWD) and rainwater usage (RUR). Rooftop runoff harvesting system was proposed as a water supply source in addition to the current one. Under such dual supply conditions, users can meet the drinking and non-drinking demand even in dry seasons at a minimum of 2 and 20 L/person/d, respectively. For rainwater harvesting adoption (considering selected regions), it was further established that amount and variation in rainfall impacts on quantity available for meeting demand. Increased catchment implies increased harvestable quantity, and with same storage higher reduction of number of NWD although with slight decrease of RUR. Also, increased storage is required for achieving higher RUR in case the same demand is maintained. But same storage can be maintained for increased demand relative to catchment size. However, rainwater catchment increase has greater impact on meeting a specified demand under given condition of rainfall quantity and variation. The RWH technology strategies presented in this study are replicable in other developing countries under site specific conditions.
基金foundation of Maa-ja vesitekniikan tuki ry.,for financing the research.
文摘Nitrite in drinking water is a potential health hazard and monitoring its concentrations in distributed water is of paramount importance. When monochloramine is used in secondary disinfection in drinking water distribution systems (DWDSs), nitrite is often formed by nitrification in the biofilm on the inner surface of distribution pipes. This article attempts to identify areas with a risk of increased nitrite concentrations as well as the main reasons leading to nitrite occurrence in a large urban DWDS in Finland using spatial inspection of obligatory monitoring data. Nitrification was found to occur throughout the study area, though nitrite was not increased everywhere. Instead, nitrite was increased close to the water treatment plants (WTPs) and was connected to fresh drinking water than stagnant drinking water. Temperature effects on nitrite concentrations were surprisingly insignificant, even though it is well known that nitrification reactions are affected by temperature. The temperature dependence of ammonium and total residual chlorine was more significant than the dependence of nitrite. The findings of this study emphasize the need to monitor nitrite concentrations close to WTPs.
文摘This study investigated coal-mine drainage(AMD)and municipal wastewater(MWW)contaminant concentrations and conducted the combined treatment in phases I and II:phase I,evaluating the effects of mixing the two based on the extent of acid neutralization and metals removal;phase II:conducting anaerobic batch reactor treatment of AMD and MWW under varying COD/sulfate ratios(0.04-5.0).In phase I,acid mine drainage water quality conditions are as follows:pH 4.5,acidity 467.5 mg/L as CaCO3,alkalinity 96.0 mg/L as CaCO3,Cl-11.8 mg/L,SO42-1722 mg/L,TDS 2757.5 mg/L,TSS 9.8 mg/L,BOD 14.7 mg/L,Fe 138.1 mg/L,Mg 110.8 mg/L.Mn 7.5 mg/L,Al 8.1 mg/L,Na 114.2 mg/L,and Ca 233.5 mg/L.Results of the mixing experiments indicated significant removal of selected metals(Fe 85~98%,Mg 0~65%,Mn 63~89%,Al 98~99%,Na 0~30%),acidity(77~95%)from the mine water and pH was raised to above 6.3.The Phase II results suggested under the wide range of COD/sulfate ratios,COD and sulfate removal varied from 37.4%-100%and 0%-93.5%respectively.During biological treatment,alkalinity was generated which leads to pH increase to around 7.6-8.5.The results suggested feasibility of the proposed technology for co-treatment of AMD and MWW.A conceptual design of co-treatment system which is expected to remove a matrix of pollutants has been provided to utilize all the locally available water resources to achieve the optimum treatment efficiency.The technology also offers an opportunity to significantly reduce capital and operating costs compared to the existing treatment methodologies used.Featured Application:In this study,we have measured the concentrations of contaminants in acid mine drainage(AMD)and municipal wastewater(MWW)and conducted the combined treatment in phases I and II.This is significant because in previous years there was a massive fish kill that is linked to the high total dissolved solids(TDS)and salinity content in the water.With the current proposed combined treatment technology,it shows high potential in reducing TDS and salinity content in the combined wastewater which will prevent similar accident(Dunkard creek fish kill in 2019)happening again.
