Effects of adding mineral adsorbents to porous concrete for enhancing the quality performance of urban runoff systems

2018 ◽  
Vol 15 (4) ◽  
pp. 489-497
Author(s):  
Sayed-Farhad Mousavi ◽  
Hojat Karami ◽  
Saeed Farzin ◽  
Ehsan Teymouri
Keyword(s):  
Compressive Strength ◽  
Oxygen Demand ◽  
Urban Runoff ◽  
Runoff Water ◽  
Quality Performance ◽  
Content Type ◽  
Porous Concrete ◽  
Mineral Adsorbents ◽  
Fast Flow

Purpose This study aims to use porous concrete and mineral adsorbents (additives) for reducing the quantity and improving the quality of urban runoff. Design/methodology/approach The effects of adding mineral adsorbents and fine grains to porous concrete is tested for increasing its performance in improving the quality of urban runoff. Two levels of sand (10 and 20 per cent) and 5, 10 and 15 per cent of zeolite, perlite, LECA and pumice were added to the porous concrete. Unconfined compressive strength, hydraulic conductivity (permeability) and porosity of the porous concrete specimens were measured. Some of the best specimens were selected for testing the improvement of runoff quality. A rainfall simulator was designed and the quality of the runoff was investigated for changes in electrical conductivity (EC), total suspended solids (TSS), total dissolved solids (TDS) and chemical oxygen demand (COD). Findings The results of this study showed that compressive strength of the porous concrete was increased by adding fine grains to the concrete mixture. Fine grains decreased the permeability and porosity of the samples. Zeolite had the highest compressive strength. Samples having pumice own maximum permeability. Samples which had perlite, had the least compressive strength and permeability. Because of the fast flow of runoff water in the porous slab and its low thickness, sufficient time was not provided for effective functioning of the additives, and the removal percentage of the pollution parameters was low. Originality/value Porous concrete can ameliorate both quantity and quality of the urban runoff.

Collection and Analysis of Urban Runoff Data in Finland

1985 ◽  
Vol 17 (6-7) ◽  
pp. 1175-1185 ◽  
Author(s):  
M. J. Melanen
Keyword(s):  
Waste Water Treatment ◽  
Urban Runoff ◽  
Waste Waters ◽  
Runoff Water ◽  
Rainfall Events ◽  
Water Treatment Plants ◽  
The City ◽  
City Centres ◽  
Sewer Networks

An extensive three-year urban hydrology programme was carried out in Finland. Data were collected and analysed on the quantity and quality of precipitation and runoff water at seven urban test catchments. During rainfall events, on the average, the proportion of surfaces generating direct runoff was found to account for 50-80 per cent of the proportion of paved surfaces in the residential catchments, and for 80-90 per cent in the city centres. Under Finnish conditions, the pollutant loads discharged to recipients with untreated runoff waters are relatively minor in comparison to those of purified waste waters, regarding organic matter and nutrients. Further measures in the Finnish sewage works should thus be focused on other factors, such as increasing the effectiveness of the existing waste water treatment plants, and decreasing the amount of leakage inflows to sewer networks.

An IoT device for striking of vertical concrete formwork

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shemin T. John ◽  
Athul Mohan ◽  
Merin Susan Philip ◽  
Pradip Sarkar ◽  
Robin Davis
Keyword(s):  
Compressive Strength ◽  
Real Time ◽  
Cost Effective ◽  
Concrete Columns ◽  
Content Type ◽  
Maturity Method ◽  
Early Age Concrete ◽  
Construction Condition ◽  
Practical Implications

PurposeTimely removal of formwork is one of the crucial aspects of construction management that directly influences the safety and quality of the structure as well as the economy of the project. Code recommendations in this regard are not widely practiced because of the difficulties in their implementations. Also, such code recommendations are not robust for all the possible construction conditions. The present paper proposes an IoT-enabled system that notifies the minimum striking time of vertical formwork based on a specified target compressive strength.Design/methodology/approachAn IoT device is proposed for the timely removal of vertical formwork by monitoring of early age concrete compressive strength in real-time. The maturity method is utilized for this purpose. The implementation of the proposed system is demonstrated on three concrete columns. The proposed system is found to be suitable for any construction condition.FindingsThe proposed system is a novel, cost-effective, IoT-enabled real-time monitoring system which includes features like cloud connectivity and remote monitoring. This system can be easily implemented at the site without any human intervention.Practical implicationsThe study explores the development of an IoT device for the timely removal of vertical formwork which will ensure quality, safety and productivity in concrete construction.Originality/valueThis paper is the first attempt to determine the minimum striking time of vertical formwork using IoT-based technology.

scholarly journals Effect of Green Roof Configuration and Hydrological Variables on Runoff Water Quantity and Quality

Water ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 960 ◽  
Author(s):  
Pascual Ferrans ◽  
Carlos Rey ◽  
Gabriel Pérez ◽  
Juan Rodríguez ◽  
Mario Díaz-Granados
Keyword(s):  
Water Quality ◽  
Vegetation Cover ◽  
Green Roof ◽  
Oxygen Demand ◽  
Substrate Type ◽  
Runoff Water ◽  
Rainfall Events ◽  
Modular Systems ◽  
Hydrological Variables

Green roofs (GRs) are a feasible solution for mitigating increased runoff volumes in urban areas. Though many studies have focused their analysis on the quantity and quality of GR runoff, with respect to the relevance of specific site conditions in GR performance, the information gathered for the tropical Andes is not sufficient. This study assessed the hydrological performance and runoff water quality of 12 green roof modular systems located at the Universidad de los Andes campus (Bogotá, Colombia). Based on 223 rainfall events spanning a 3-year period, average rainfall retention was 85% (coefficient of variation = 29%). t-tests, the Welch Test, multiple linear regressions, and correlation analysis were performed in order to assess the potential effect of air temperature, substrate type, vegetation cover, relative humidity, antecedent dry weather period (ADWP), rainfall duration, and rainfall maximum intensity. In some cases, GR design variables (i.e., substrate type and vegetation cover) were found to be significant for describing rainfall retention efficiencies and, depending on the GR type, some hydrological variables were also correlated with rainfall retention. Rainfall and GR runoff from 12 rainfall events were also monitored for total Kjeldahl nitrogen (TKN), nitrates, nitrites, ammonia, total phosphorus (TP), phosphates, pH, total dissolved solids (TDS), total suspended solids (TSS), color, turbidity, biological oxygen demand (BOD), chemical oxygen demand (COD), total coliforms, metals (i.e., zinc, copper, nickel, lead, selenium, aluminum, barium, boron, calcium, strontium, iron, lithium, magnesium, manganese, potassium, sodium), and polyaromatic hydrocarbons (PAHs). The results obtained confirmed that GR systems have the ability to neutralize pH, but are a source of the rest of the aforementioned parameters, excluding PAHs (with concentrations below detection limits), ammonia, TSS, selenium and lithium, where differences with control cases (rainfall and plastic panel runoff) were not statistically significant. Substrate type, event size, and rainfall regime are relevant variables for explaining runoff water quality.

Proposed models to measure the quality of highway projects

2017 ◽  
Vol 24 (6) ◽  
pp. 988-1003 ◽  
Author(s):  
Saad Abdel-Karim El-Hamrawy ◽  
Ahmed Ebrahim Abu El-Maaty ◽  
Ahmed Yousry Akal
Keyword(s):  
Regression Analysis ◽  
Quality Improvement ◽  
Linear Regression ◽  
Linear Regression Analysis ◽  
Quality Measurement ◽  
Quality Performance ◽  
Highway Projects ◽  
Content Type ◽  
Factors Influencing

Purpose Quality measurement is the trigger for quality improvement. Indeed, what gets measured gets done. The real scope of quality improvement in construction projects is the difficulty and-maybe-lack of quality measurement methods. The purpose of this paper is to identify the factors influencing the quality performance of highway projects in Egypt. Furthermore, this paper also contributes to develop models to measure the quality level of these projects. Design/methodology/approach A literature review is conducted to compile a list of factors influencing the quality of highway projects. The resulting list of factors is subjected to a questionnaire survey which was sent to owners, consultants and contractors of highway projects in Egypt. Furthermore, linear regression analysis and statistical fuzzy approaches are adopted for modeling process. Findings The survey results show that availability of experienced staff in the owner’s and contractor’s teams during the project execution, asphalt quality and type used in the construction process, pavement is not designed according to the regional conditions, and contractor’s labors and equipment capability are among the most important factors influencing quality performance. Originality/value The main contribution of this study is to develop models to measure the quality of highway projects in Egypt. The first model is based on the linear regression analysis, while the second one is based on a statistical fuzzy approach which is a hybrid approach from the fuzzy logic and regression analysis. Validation of the models reveals that the linear regression and the statistical fuzzy models can accurately assess expected quality of any future highway projects at confidence levels 68.97 and 87.44 percent, respectively.

Post-thermal properties of Portland cement concrete made with copper slag as fine aggregates

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
N. Suresh ◽  
Manjunatha M.
Keyword(s):  
Compressive Strength ◽  
Elevated Temperature ◽  
Copper Slag ◽  
Strength Properties ◽  
Thermal Strength ◽  
Physical Test ◽  
Content Type ◽  
Slag Content ◽  
Sem Studies

Purpose The purpose of this paper is to investigate the effect of elevated temperature on mechanical and physical properties of concrete specimens obtained by substituting the river sand with copper slag (CS) at proportions of 25%, 50%, 75% and 100%. The specimens were heated in an electric furnace up to 100, 200, 300, 400, 500 and 600 C and kept at these temperatures for 2 h duration. After the specimens were cooled in the furnace, mass loss, ultrasonic pulse velocity (UPV), compressive strength, split tensile strength (STS), flexural strength (FS) and modulus of elasticity (MOE) values were determined. No spalling occurred in the specimens after subjected to elevated temperature. The surface cracks were observed only in specimens exposed to 600 C. The maximum reduction in compressive strength and STS at 600C is 50.3% and 36.39% for referral mix (NC), 18% and 16% for specimens with 100% CS (MCS4). The reduction in MOE of specimens is observed to be high as copper slag content increases with increasing temperature. Scanning electron microscopy (SEM) studies are carried out to examine the changes in micro-structures of specimens after exposed to elevated temperatures. Design/methodology/approach After casting of concrete specimens, it is cured for 28 days. After attainment of 28 days age, the concrete specimens is taken out from the curing tank and allowed to dry for 2 days to remove any moisture content in the specimens to prevent explosive spalling during the time of heating. The prepared concrete specimen is subjected to temperatures of 100°C, 200°C, 300°C, 400°C, 500°C and 600°C up to 2 h duration. The physical test, mechanical test and SEM studies are carried out after cooling of specimens to room temperature (RT). The quality of concrete specimens is measured by conducting UPV test after cooling to RT. Findings The post-thermal strength properties of concrete specimens with copper slag contents are higher than referral mix concrete. The reduction of MOE of concrete specimens is more with incremental in copper slag content with increase in temperatures. Furthermore, the quality of concrete specimens is ranging from “good to medium” up to 500C temperatures based on UPV test. Originality/value In this research work, the natural sand is fully replaced with copper slag materials in the concrete mixes. The post-thermal strength properties like residual compressive strength, residual STS, residual FS and residual MOE is higher than referral mix after subjected to elevated temperature conditions. Higher density and toughness properties of copper slag materials will contribute to concrete strength. The effect of elevated temperature is more on MOE of concrete specimens having higher copper slag contents when comparing to specimens compressive strength.

DECOLOURIZATION AND COD REMOVAL OF WASEWATER FROM ETHANOL PRODUCTION PROCESS FROM MOLASSES BY COAGULANTION USING INORGANIC ALUM

2010 ◽  
Vol 13 (3) ◽  
pp. 92-102
Author(s):  
Trung Duc Le
Keyword(s):  
Ethanol Production ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Treated Wastewater ◽  
Treatment Processes ◽  
Physico Chemical ◽  
Biological Methods ◽  
Treatment Step ◽  
Main Material

The industrial production of ethanol by fermentation using molasses as main material that generates large quantity of wastewater. This wastewater contains high levels of colour and chemical oxygen demand (COD), that may causes serious environmental pollution. Most available treatment processes in Vietnam rely on biological methods, which often fail to treat waste water up to discharge standard. As always, it was reported that quality of treated wastewater could not meet Vietnameses discharge standard. So, it is necessary to improve the treatment efficiency of whole technological process and therefore, supplemental physico-chemical treatment step before biodegradation stage should be the appropriate choice. This study was carried out to assess the effect of coagulation process on decolourization and COD removal in molasses-based ethanol production wastewater using inorganic coaglutant under laboratory conditions. The experimental results showed that the reductions of COD and colour with the utilization of Al2(SO4)3 at pH 9.5 were 83% and 70%, respectively. Mixture FeSO4 – Al2(SO4)3 at pH 8.5 reduced 82% of colour and 70% of COD. With the addition of Polyacrylamide (PAM), the reduction efficiencies of colour, COD and turbidity by FeSO4 – Al2(SO4)3 were 87%, 73.1% and 94.1% correspondingly. It was indicated that PAM significantly reduced the turbidity of wastewater, however it virtually did not increase the efficiencies of colour and COD reduction. Furthermore, the coagulation processes using PAM usually produces a mount of sludge which is hard to be deposited.

Hydro-geochemical properties with respect to landuse in the southernmost river of Kerala

2018 ◽  
Vol 6 (1) ◽  
Author(s):  
Badusha M. ◽  
Santhosh S
Keyword(s):  
Organic Carbon ◽  
Drainage Basin ◽  
Anthropogenic Activities ◽  
Oxygen Demand ◽  
Ion Concentration ◽  
Total Hardness ◽  
Hydrogen Ion Concentration ◽  
Geochemical Properties ◽  
Quality Of Water

The hydro geochemical features of Neyyar River for a period of one year from May 2015 to April 2016 were analyzed. Six sampling sites were fixed considering physiography and present landuse pattern of the river basin. The residents in the drainage basin are primarily responsible for framing a better landuse and thereby maintain a good water and sediment regime. Geospatial pattern of the present landuse of the study area indicated that the sustainability of this river ecosystem is in danger due to unscientific landuse practices, which is reflected in the river quality as well. The parameters such as hydrogen ion concentration, electrical conductivity, chloride, Biological Oxygen Demand, total hardness and sulphate of river water and Organic Carbon of river bed sediments were analyzed in this study. The overall analysis shows that the highland areas are characterized by better quality of water together with low organic carbon, which is mainly due to better landuse and minimal reclamation. The midland and lowland areas are characterized by poor quality of water with high organic carbon, which is due to high anthropogenic activities and maximum pollutants associated with the region together with the alteration in landuse from a traditional eco-friendly pattern to a severely polluted current pattern.

Incorporating concepts from physical theory into stochastic modelling of urban runoff pollution

1998 ◽  
Vol 37 (1) ◽  
pp. 179-185
Author(s):  
Morten Grum
Keyword(s):  
Stochastic Model ◽  
Continuous Time ◽  
Measurement Errors ◽  
Physical Theory ◽  
Oxygen Demand ◽  
Stochastic Modelling ◽  
Urban Runoff ◽  
Primary Input ◽  
Deterministic Modelling ◽  
Runoff Pollution

On evaluating the present or future state of integrated urban water systems, sewer drainage models, with rainfall as primary input, are often used to calculate the expected return periods of given detrimental acute pollution events and the uncertainty thereof. The model studied in the present paper incorporates notions of physical theory in a stochastic model of water level and particulate chemical oxygen demand (COD) at the overflow point of a Dutch combined sewer system. A stochastic model based on physical mechanisms has been formulated in continuous time. The extended Kalman filter has been used in conjunction with a maximum likelihood criteria and a non-linear state space formulation to decompose the error term into system noise terms and measurement errors. The bias generally obtained in deterministic modelling, by invariably and often inappropriately assuming all error to result from measurement inaccuracies, is thus avoided. Continuous time stochastic modelling incorporating physical, chemical and biological theory presents a possible modelling alternative. These preliminary results suggest that further work is needed in order to fully appreciate the method's potential and limitations in the field of urban runoff pollution modelling.

Non-steady variations of SOD and phosphate release rate due to changes in the quality of the overlying water

2000 ◽  
Vol 42 (3-4) ◽  
pp. 265-272 ◽  
Author(s):  
T. Inoue ◽  
Y. Nakamura ◽  
Y. Adachi
Keyword(s):  
Release Rate ◽  
Oxygen Demand ◽  
Phosphate Concentration ◽  
Sediment Oxygen Demand ◽  
Biochemical Reactions ◽  
Overlying Water ◽  
Phosphate Release ◽  
Do Concentration ◽  
The Difference

A dynamic model, which predicts non-steady variations in the sediment oxygen demand (SOD) and phosphate release rate, has been designed. This theoretical model consists of three diffusion equations with biochemical reactions for dissolved oxygen (DO), phosphate and ferrous iron. According to this model, step changes in the DO concentration and flow velocity produce drastic changes in the SOD and phosphate release rate within 10 minutes. The vigorous response of the SOD and phosphate release rate is caused by the difference in the time scale of diffusion in the water boundary layer and that of the biochemical reactions in the sediment. Secondly, a negative phosphate transfer from water to sediment can even occur under aerobic conditions. This is caused by the decrease in phosphate concentration in the aerobic layer due to adsorption.

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