Mohammad Maksimul Islam | North Carolina State University (original) (raw)

Papers by Mohammad Maksimul Islam

Proceedings of the 5th International Conference on Civil Engineering for Sustainable Development (ICCESD 2020), 7~9 February 2020, KUET, Khulna, Bangladesh, 2020

Dhaka, the capital of Bangladesh, is one of the most polluted cities in the world in terms of air... more Dhaka, the capital of Bangladesh, is one of the most polluted cities in the world in terms of air quality. Particulate matter (PM) concentrations of the city frequently exceed the national air quality standards. Although meteorological parameters play a vital role in air quality through downwind transportation and formation of the secondary PM, few studies have been conducted so far to explore the association between meteorology and air quality. In this paper, we apply a multiple linear regression approach to build a statistical model with PM as response variable, and daily mean temperature, precipitation, relative humidity, solar radiation, wind speed, and wind direction components as potential predictors. For analysis, we employ 24-hour average fine (PM2.5) and coarse (PM2.5-10) particulate matter concentration and meteorological data for the year 2002 to 2004 as this work expands the work by Islam, Afrin, Ahmed, & Ali (2015). The result depicts that meteorological variables can explain 57% and 35% variability in the 24-hour average PM2.5 and PM2.5-10 concentration respectively when only the direct influence of the parameters is considered. After the inclusion of interaction terms among the parameters, the PM2.5 model performances improve by 12% although there is no improvement for coarser fraction. The relative humidity is the most dominating factor explaining 72% of the total variability explained by the PM2.5-10 model. Under a humid environment, there is a reduction of coarser particles as the settling and wet deposition of the particles is fostered by high moisture content. Oppositely for PM2.5, temperature, wind speed, and wind direction are the most influential parameters. They altogether explain 94% of the total variability explained by the PM2.5 model. Similar to relative humidity, temperature has an inverse relationship with both PM fractions due to the radiative cooling by particles and also for the shutdown of specific PM sources during the non-winter period. Overall, the outcome of this study provides deeper insight regarding the influence of meteorology and their interaction on PM concentrations. The statistical approach developed in the paper is powerful to develop PM forecasting model for predicting the next day PM given the forecasted meteorological data.

Proceedings of the 5th International Conference on Civil Engineering for Sustainable Development (ICCESD 2020), 7~9 February 2020, KUET, Khulna, Bangladesh, 2020

Rainwater harvesting system (RWH) is considered an environmentally sound solution to provide safe... more Rainwater harvesting system (RWH) is considered an environmentally sound solution to provide safe drinking water. It is particularly suitable for Bangladesh because of its having tropical monsoon with a large seasonal cycle in rainfall. Although few studies dealt with the technical feasibility of the RWH system, reliability based cost-benefit analyses are still scarce. This study aims at assessing the financial feasibility of RWH system in Khulna, a coastal district in Bangladesh. We apply a mass balance based behavioral model named 'Yield-After-Spillage (YAS)' to conduct reliability analysis. We use historical as well as future predicted rainfall data in the model to explore the effect of climate change on reliability and financial feasibility. We conducted a social survey to collect necessary information related to RWH system including roof area, roof material, water demand, existing water supply system and cost of materials. Cost-benefit analysis reveals that 85-95% of total RWH installation cost is for the storage reservoir, making it the most expensive unit of the system. We find 'net present value (NPV)' of a typical RWH system positive indicating that RWH is a financially viable solution in the study area. Payback period varies between 3-13 years depending on the precipitation variability. For 100 litre/day demand, predicted rainfall for the 2041-2070 period showed 1.5 times larger storage tank requirement compared to that for historical precipitation scenario to attain 90% volumetric reliability, which results in a substantial increase in cost, and 20% reduction in NPV. However, for 200 litre/day demand, historical precipitation scenario cannot provide more than 53% reliability.

Proceedings of 11th Global Engineering, Science and Technology Conference 18 - 19 December, 2015, BIAM Foundation, Dhaka, Bangladesh, ISBN: 978-1-922069-92-4, 2015

This study focuses on the measurement of phosphorus concentration in Hatirjheel Lake, one of the ... more This study focuses on the measurement of phosphorus concentration in Hatirjheel Lake, one of the largest water bodies in Dhaka city and interpret the development of eutrophication over the years 1989, 1999 and 2009. Over the years Hatirjheel has been the water body used for dumping the sewage of the Dhaka city as it is connected with the rest water bodies; Gulshan Lake, Banani Lake, Dhanmondi Lake around this mega city. Thus the study of development of eutrophication is necessary for this lake to understand the pollution it creates and the environmental effect that it has around its surroundings. In order to simulate the phosphorus model developed by Reckhow, initially Landsat images were classified into four categories of land use pattern utilizing the tool ArcGIS. The Landsat images gathered were from the years 1989, 1999 and 2009 so that the development of eutrophication can be identified in a long-term basis. The areal data extracted from the image classification of the Landsat images were then used in the equations developed by Reckhow in his phosphorus model. From the final data of the phosphorus model it was observed that the concentration of phosphorus over the span of two decades has increased greatly. One of the many reasons that could be identified as the increase of the phosphorus concentration is development of urban areas around the lake area. The results obtained from this study will help in assessing the extent of the development of the Hatirjheel Lake project in initiated for environmental restoration of Hatirjheel area.

Proceedings of 10th Global Engineering, Science and Technology Conference 2-3 January, 2015, BIAM Foundation, Dhaka, Bangladesh, ISBN: 978-1-922069-69-6, 2015

As Bangladesh has tropical monsoon with large seasonal cycle in rainfall, Rainwater Harvesting (R... more As Bangladesh has tropical monsoon with large seasonal cycle in rainfall, Rainwater Harvesting (RWH) system and its utilization could be a good and environmentally sound solution for providing safe drinking water. Although rainwater harvesting has already been promoted in different coastal areas in Bangladesh to a limited scale for drinking purpose, improper storage reservoirs prohibit people getting full benefit from it. Moreover, temporal variability of precipitation , which is the main governing factor in the design of a storage tank in Rainwater Harvesting Systems (RWHS), is expected to be altered in future under the effects of climate change. This can introduce an element of uncertainty in the design of storage reservoirs if this variability is not taken into consideration. The objective of this paper is to report on reliability problems of existing rainwater harvesting system in coastal rural areas of Mongla, Bangladesh. This study aims at developing a simulation model as tank sizing tool incorporating all the design variables and also climate change variability and assessing reliability in terms of failure time units and demand satisfaction level with the help of this model.This simulation model is developed based on mass balance equation in which historical as well as predicted future climate data are used. Historical precipitation data are collected from Bangladesh Meteorological Department (BMD) whereas predicted future data are from a climate model named PRECIS. The physical data input includes roof area, run off coefficient and reservoir size whereas social status data includes water demand and household size. The study has shown that, for a water demand of 5 lpcd, volumetric reliability lies in the range of 35-37% in case of individual household based rainwater harvesting system for historical rainfall pattern of the study area whereas the range becomes 48-50% for predicted future precipitation scenario depending on existing roof areas and corresponding storage tank sizes. The volumetric reliability of community rainwater harvesting systems for historical data (26%) is almost half of the value obtained from future precipitation scenario (56%) for a water demand of 5 lpcd. Reliability becomes lower for higher water demand as expected. Time reliability of both individual and community rainwater harvesting system is considerably lower compared to volumetric reliability for both observed and predicted precipitation data. It implies that although existing systems manage to deliver a portion of water demand, the number of months in which demand is fully met is very small. Finally, tank sizing curves for the study area have been developed by which one could obtain the reliable size of the water storage tank for given data on household size, per capita water demand and roof area. The research findings presented in this paper could be applied in areas with similar socioeconomic status and climatic condition.

International Journal of Environmental Science and Development, Vol. 6, No. 5, May 2015, 2015

Bangladesh is one of the most vulnerable countries of the world to climate change. The magnitude ... more Bangladesh is one of the most vulnerable countries of the world to climate change. The magnitude and frequency of extreme events such as high intensity rainfall, flash flooding, severe droughts, etc. are expected to be altered in future as a consequence of this change. This can introduce an element of uncertainty in the design of hydraulic structures, urban drainage systems, and other water-sensitive structures, if the variability is not taken into consideration. This study aims at developing a regional Intensity-Duration-Frequency (IDF) relationship for Dhaka city for present as well as future climatic scenarios. The scaling properties of extreme rainfall are examined to establish scaling relationship behavior of statistical moments over different durations. The results show that a rainfall property in time does follow a simple scaling process. A scale invariance concept is explored for disaggregation (or downscaling) of rainfall intensity from low to high resolution and is applied to the derivation of scaling IDF curves. These curves are developed based on scaling of the generalized extreme value (GEV) and Gumbel probability distributions. It is seen that scaled estimates are relatively close to observed estimates.

Proceedings of 10th Global Engineering, Science and Technology Conference 2-3 January, 2015, BIAM Foundation, Dhaka, Bangladesh, ISBN: 978-1-922069-69-6, 2015

Dhaka, the capital of Bangladesh, has experienced water logging for last couple of years as the s... more Dhaka, the capital of Bangladesh, has experienced water logging for last couple of years as the storm water drainage systems are often unable to manage peak runoff volume. Moreover, precipitation intensity and pattern are expected to be altered due to climate change and such changes are likely to lead to severe flooding in urban areas of Bangladesh. This study aims to assess the effect of climate change on flow of Hatirjheel-Begunbari Khal storm water drainage system as it is considered one of the major drainage channels of Dhaka city. As Hatirjheel works as a large storm water detention area and also a regulatory system, different scenerios are considered while assessing the future flow. The rational fromula was used to assess the flow instead of hydrologic model due to lack of observed flow data for calibration and validation. The study involves DEM based catchment delineation using GIS. The DEM was reconditioned prior to catchment delineation to create a channelization effect intended to mimic the existing storm sewer network of the city. A future land use scenario is considered based on the analysis of land use maps of three different time interval for determining future runoff coefficient. The peak rainfall intensity is obtained from the IDF curve of Dhaka city developed considering the future precipitation data of a climate model. Although Hatirjheel is found to be an effective retention and regulatory system to minimize the flow, result of this study shows an alarming increase in flow in future which might cause severe flooding in the surrounding area.

2nd International Conference on Advances in Civil Engineering 2014 (ICACE-2014) 26 –28 December, 2014 CUET, Chittagong, Bangladesh, 2014

This paper aims at understanding the meteorological influences in ambient air quality of Dhaka ci... more This paper aims at understanding the meteorological influences in ambient air quality of Dhaka city by analyzing air quality and meteorological data. Trends in air quality over the past decade show large seasonal variations in both PM2.5 and PM10 concentrations, exceeding the national standards during dry season, while remaining somewhat below the standards during rainy season. The number of rainy days in a month during the wet period has been found to have strong negative correlation with average monthly PM concentrations. However, the daily amount of rainfall during the rainy period does not seem to have any effect on the daily PM concentration as PM2.5-10 showed insignificant negative correlation, while PM2.5 showed insignificant positive correlation. This indicates that although precipitation in general may promote wet deposition of particulates, the daily rainfall itself does not significantly dictate the magnitude of PM and therefore it may not be a significant indicator of air pollution potential. A weak albeit positive correlation of PM with wind speed from northwestern direction suggests that dilution of PM due to increased wind speed is very low. The coarse fraction of PM exhibited positive correlation with incident solar radiation suggesting increased formation of coarse nitrate particles by enhanced photochemical activity. Strong negative correlation of PM with relative humidity indicates possible absorption of moisture by particulate matter promoting settling and removal from suspension. Significant negative correlation between PM and temperature indicates that higher PM tends to reduce atmospheric temperature due to its net negative radiative forcing. Results from this study emphasize the need for understanding air quality under the context of local meteorological conditions.

2nd International Conference on Advances in Civil Engineering 2014 (ICACE-2014) 26 –28 December, 2014 CUET, Chittagong, Bangladesh, 2014

This paper aims at presenting overall air quality scenario of Dhaka, capital of Bangladesh, by as... more This paper aims at presenting overall air quality scenario of Dhaka, capital of Bangladesh, by assessing yearly, monthly, seasonal as well as diurnal variation of all the criteria pollutant (PM, NOX, SO2, CO and O3), except Pb. Effects of seasons, eid, weekend and hartal days on air quality of Dhaka are also discussed.Trace metals in PM10 are measured in three different locations in Dhaka in both dry and wet seasons in order to find out their seasonal sources. Both yearly 24-hr average PM10 and PM2.5 exceed Bangladesh National Air Quality Standards and WHO Guideline values. The yearly average concentration of NOx also nearly exceeds the standards, while SO2, CO, O3 are far below the standards. Not only PM, but also NOx, SO2, CO show seasonal variation. Only O3 shows distinctive diurnal variation throughout the year. It appears from daily plots that concentration of only PM10 appears to be reduced in weekends while PM10, PM2.5 and NOx are observed to drop immediately on hartal days. Concentration of NOx seems to be abated on eid day and remain lower for the next few days. PM2.5 exhibits strong positive correlation with NOx and CO in both dry and wet periods suggesting same pollution source in all periods. Higher concentration of trace metals in rainy season compared to dry season indicates possible transmission of metals by wind blowing from southeast direction during rainy season, suggesting that the foundries, small industries, Pb-battery recycling plants etc. in old town of Dhaka situated in the southeastern periphery of the city are contributing to the degraded air quality.

11th International Conference on Mechanical Engineering, ICME 2015, Dhaka, Bangladesh, 2015

This paper represents the effects of brick kilns on the seasonal variation of particulate matter ... more This paper represents the effects of brick kilns on the seasonal variation of particulate matter in the air of Dhaka. Trends in air quality over the past decade show large seasonal variations in both PM2.5 and PM10 concentrations, exceeding the national standards during dry season, while remaining somewhat below the standards during rainy season. Wet deposition due to precipitation is considered as the reason for this seasonal variation. The aim of the study is to establish brick kilns as one of the sources of PM by analyzing air quality and meteorological data statistically with the help of Pearson Correlation Coefficient and statistical P-value and thus a major factor of seasonal variation as brick kilns are in operation only in dry period of the country. To assess the effect of brick kilns, wind speed and direction were considered among the meteorological parameters as emissions of brick kilns located at the northern periphery of the city are transported by wind. However, precipitation was also correlated with PM to identify the effect of wet deposition. The number of rainy days in a month during the wet period has been found to have strong negative correlation with average monthly PM concentrations. However, the daily amount of rainfall during the rainy period does not seem to have any effect on the daily PM concentration as PM2.5-10 showed insignificant negative correlation, while PM2.5 showed insignificant positive correlation. This indicates that although precipitation in general may promote wet deposition of particulates, the daily rainfall itself does not significantly dictate the magnitude of PM and therefore it may not be a significant factor for seasonal variation. High PM concentrations have been found to be associated with winds coming from northern and northwestern directions during the dry season, suggesting that the brick kiln clusters situated in the northern periphery of the city are contributing to the degraded air quality by emitting particulate matter. The results of the study indicate that effect of wet deposition due to precipitation on the reduction of PM is very low and closure of brick kilns during rainy season is the main reason of the seasonal variation of particulate matter in Dhaka city.

6th International Chemical and Environmental Engineering Conference 27-29 December 2015, Kuala Lumpur, Malaysia, 2015

Bangladesh faces waste management challenges in most of the cities. The untreated fecal sludge is... more Bangladesh faces waste management challenges in most of the cities. The untreated fecal sludge is disposed to the water bodies, agricultural fields and lands indiscriminately which in turn is greatly polluting the environment and posing serious health effects. However, it contains nutrients and organic matters which can be used to increase the agricultural productivity. This resource recovery option will eventually reduce pollution load to the environment. This study tried to determine the physicochemical characteristics of dried fecal sludge with a view to assessing the fertilizer potentiality. The fuel potential of the sludge was also tried to assess by determining calorific value using oxygen bomb calorimeter. In this study fecal sludge samples were collected from drying beds in Satkhira, Khulna. Samples of different ages were also collected to determine the impact of sludge age on fertilizer and fuel potentiality as well. A wide variety of parameters of sludge were determined to ascertain the physicochemical characteristics which included color, odor, moisture content, pH, Organic Carbon, Total Nitrogen, C:N ratio, Phosphorus, Potassium, Sulfur, Zinc, Copper, Chromium, Cadmium, Lead, Nickel etc. The results found in experiments met the Bangladesh standard for organic fertilizer. The average calorific values were found to be 7.1 and 4.32 MJ/Kg for 15 days and 21 days dried samples respectively indicating a decrease in fuel potentiality with age.

Proceedings of the 3rd International Conference on Civil Engineering for Sustainable Development (ICCESD2016), 12~14 February 2016, KUET, Khulna, Bangladesh (ISBN: 978-984-34-0265-3), 2016

Dhaka, the capital of Bangladesh, is undergoing rapid urbanization process. Due to the unplanned ... more Dhaka, the capital of Bangladesh, is undergoing rapid urbanization process. Due to the unplanned urban sprawl, the city dwellers are deprived of basic human rights among which water supply have appeared as the most censorious issue. Water supply in Dhaka city is mostly dependent on groundwater extraction and around 87% of the supplied water is extracted from groundwater sources. Such extensive pumping of groundwater and reduced infiltration due to increased urbanization have depleted groundwater storage calling into question the sustainability of the city's groundwater supply.Water Sensitive Urban design (WSUD) acknowledges and aims at overcoming these impacts by integrating water into urban development and planning to magnify the opportunities for sensitive water cycle management.The present research has been undertaken with a view to develop and design an urban area in such a way that groundwater recharge can be enhanced on a regular basis. Applicability of different measures of WSUD have been studied in this study and evaluated in terms of their costing and effectiveness in increasing groundwater recharge in Dhaka city. This study mainly focuses on two options named Infiltration Trench and Permeable Pavement considering "Purbachal New Town" as the study area. Potential infiltration of water by these processes has been assessed and based on this, design of the applied measures are provided along with the costing. Seemingly significant infiltration and potential increase of groundwater recharge has been found due to theoretical application of these approaches in the study area. Results of this study would help policy makers and the relavant authorities to develop sustanable urban areas and make the city a more livable one.

8th International Perspective on Water Resources and the Environment Sri Lanka, 4-6 January, 2016, 2016

This paper aims at simulating two Phosphorus models to assess their suitability to use for Hatirj... more This paper aims at simulating two Phosphorus models to assess their suitability to use for Hatirjheel which is one of the largest lakes of Dhaka City, the capital of Bangladesh. Two empirical models-the Reckhow model and the Vollenweider model were used in this study which are based on the contribution of Phosphorus resulting from different land patterns. Various land patterns within the catchment of the lake were identified and digitized using geographic information system. Maximum likelihood supervised classification system was used to classify different land uses and determine contributing areas. To validate the model results several samples were collected from different locations of the lake in two separate time periods and Phosphorus concentration of those samples were evaluated in the laboratory. The average Phosphorus concentration was found to be close to those obtained from the models. This suggests that Reckhow and Vollenweider models could be used for Phosphorus modelling for the lakes in Bangladesh. This is important as study related to Phosphorous modelling of lakes has not been accomplished in the country yet. Moreover, the outcome of the study was used further to assess tropic condition of Hatirjheel Lake as Phosphorus is considered as a key element to accelerate eutrophication process. The Hatirjheel Lake can be termed as hyper-eutrophic based on its high Phosphorus content indicating excessive biological productivity within the lake probably due to extreme human

8th International Perspective on Water Resources and the Environment, Sri Lanka, 4-6 January, 2016, 2016

SWMM model was used in this study to model community integrated rainwater harvesting (RWH) system... more SWMM model was used in this study to model community integrated rainwater harvesting (RWH) system for a community of a water scarce urban coastal area of Bangladesh. Performance of the system was then assessed by developing a behavioral model in MATLAB environment based on SWMM model output. Four performance indicators-volumetric reliability, time reliability, water utilization and water spillage were determined using the model. A sensitivity analysis was also performed to assess the effect of major parameters on the performance of community (RWH) system. Moreover, monthly demand satisfaction level and failure percentages were also determined for various cases. Although the effect of YAS and YBS algorithm on the performance of community rainwater harvesting system was not found significant, community size, water demand and time steps appeared to have marked contribution to the performance. For a certain storage tank, volumetric and time reliability were found to be lower for higher community size. Furthermore it was seen that, the smaller the community size, the smaller would be the tank size in which maximum reliability achieves. For low water demand, increase in tank size caused an increase in reliability initially and reliability did not increase further with tank size after reaching its maximum value. Reliability did not show a marked increase with tank size for higher water demand. Higher volumetric reliability was obtained in case of daily time step data and it was true for time reliability also. Volumetric reliability curves for daily and weekly time step were very close to each other whereas a small deviation was observed in case of time reliability. In both cases, reliability curves corresponding to monthly time step were considerably lower than daily and weekly time step and the deviation tended to decrease with tank size increment. The results of the study suggest that rainwater harvesting system could be implemented centrally for the community with sufficient reliability provided that storage reservoir ought to be selected carefully using the performance curves developed in this study for various tank sizes, water demands and community sizes.

8th International Perspective on Water Resources and the Environment, Sri Lanka, 4-6 January, 2016, 2016

This paper aims at assessing the effect of land use and climate change on the flow of Hatirjheel-... more This paper aims at assessing the effect of land use and climate change on the flow of Hatirjheel-Begunbari Khal storm water drainage system, the major drainage channel of Dhaka city. Catchment of Hatirjheel-Begunbari Khal system has changed rapidly due to unplanned urbanization coupled with filling up with agricultural land and also wetlands by several thousand real estate companies which in turn caused an increase of inflow to the drainage system. Moreover, precipitation intensity and pattern are expected to be altered due to climate change and such changes are likely to lead to severe flooding in urban areas of Bangladesh specially in Dhaka. This study involves DEM based catchment delineation using GIS. The change in land use pattern of the catchment was explored by analyzing present land use map and Landsat imageries of 1989, 1999 & 2009. After classifying the Landsat images using maximum likelihood supervised classification, trend analysis was employed to detect the changes of different land covers. Finally percentage of different land covers were predicted for future time periods based on the trend analysis that were used to determine runoff coefficient of rational formula. The peak rainfall intensity was obtained from the IDF curves of Dhaka city developed previously considering observed and future precipitation data of a climate model. As Hatirjheel works as a large storm water detention area and also a regulatory system, different operational scenerios were considered while assessing the future flow. It was observed form the land use analysis and IDF curves that runoff coefficient and peak precipitation intensity would be increased by around 4.9% and 135% on 2025 and 12% and 177% on 2040 respectively considering 5 year return period. Considering the effect of both land use change and precipitation variability due to climate change, it was found that peak flow of Hatirjheel-Begubari khal system would likely to rise about 107% and 143% on 2025 and 2040 respectively which might cause severe water logging and eventually flooding in the city. 2

International Conference on Recent Innovation in Civil Engineering for Sustainable Development (IICSD-2015), 2015

The Buriganga-Turag River system is one of the main river systems flowing beside Dhaka city, capi... more The Buriganga-Turag River system is one of the main river systems flowing beside Dhaka city, capital of Bangladesh. Because of the tanneries and other industries in the riverbank and for using the river as dumping ground for the liquid and solid wastes, the river system is now under threat of extinction. The paper represents an extensive study to assess pollution load into the Buriganga-Turag river system especially due to industrial discharges. This paper is the presentation of alarming pollution and contamination created by the riverside industries. The assessment was carried out by finding out industrial discharge sources into the rivers by thorough field study followed by pollution load determination which included collection of waste water from the discharge points, determination of flow and finally testing of collected water in the laboratory. The study has identified six major outfalls of industrial pollutants in the river system. After calculating present pollution loads a comparative analysis was conducted with the past pollution loads mentioned in different previous studies. Result of this study shows massive pollution loads discharging into the river system form the adjacent industries. Moreover, comparative analysis reveals that present loads are significantly higher compared to previous time periods which are alarming.

International Conference on Recent Innovation in Civil Engineering for Sustainable Development (IICSD-2015), 2015

Precipitation variability, which is the main governing factor in the design of a storage tank in ... more Precipitation variability, which is the main governing factor in the design of a storage tank in Rainwater Harvesting Systems, is expected to be altered in future under the effects of climate change. This can introduce an element of uncertainty in the design of storage reservoirs if this variability is not taken into consideration. The objective of this paper is to assess reliability of community integrated rainwater harvesting system for a community of a water scarce urban coastal area of Bangladesh considering historical as well as predicted future precipitation variability due to climate change. A behavioral model is developed in MATLAB environment based on mass balance equation incorporating both YAS and YBS algorithm. Historical precipitation data of the study area are collected from Bangladesh Meteorological Department (BMD) whereas predicted future data are from a climate model named PRECIS. To assess the effect of climate change the whole time periods were divided into four consecutive time periods (

International Conference on Recent Innovation in Civil Engineering for Sustainable Development (IICSD-2015), 2015

This paper presents the application of SWMM model to assess the potential of community integrated... more This paper presents the application of SWMM model to assess the potential of community integrated rainwater harvesting system for a community of a water scarce urban coastal area of Bangladesh. A behavioral model was developed in MATLAB environment to assess four performance indicators named-time reliability (Re), volumetric reliability (Rv), water utilization (WU) and water spillage (WS) using the output of SWMM model. Pearson's correlation was used to determine the degree of association between the indicators. Moreover statistical P value was evaluated for each correlation to determine the significance of correlation coefficient. Effects of different design variables on correlation were also assessed by varying community size, water demand, time steps, time periods and algorithms. Strong (r > 0.9) and significant (p<0.05) correlations between the performance parameters for different community sizes indicate that precipitation of the study area was high enough to serve large as well as small community. While calculating correlations using three different time steps-daily, weekly and monthly, it was found that although all the correlations were strong and significant, correlations of volumetric reliability with time reliability, water utilization and water savings were comparatively higher for larger time steps. It is seen that higher the water demand, comparatively lower is the correlation exist between Rv and other parameters (Re, WU and WS) and Re and other parameters (Re, WU and WS). No significant variation was found for YAS and YBS algorithm while assessing correlations among the parameters. Strong and significant correlations between the performance indicators in all cases implies that their association could be described by linear relationships. This finding is important because if any of these parameters is known, other could be determined by the linear relationship exist between them.

International Conference on Recent Innovation in Civil Engineering for Sustainable Development (IICSD-2015), 2015

This study aims at modeling community integrated rainwater harvesting system as modeling of rainw... more This study aims at modeling community integrated rainwater harvesting system as modeling of rainwater harvesting system for a community has not been conducted yet. This paper uses two modeling concept-rational formula and SWMM model for assessing the potentiality of community rainwater harvesting system. Performance indicators of rainwater harvesting system were assessed by developing a behavioral model in which runoff obtained from both the SWMM model and rational formula based simulation model were used. The model was developed based on mass balance equation incorporating both YAS and YBS algorithm. Four performance parameters were determined in this study named-time reliability (Re), volumetric reliability (Rv), water utilization (WU) and water spillage (WS) to assess the relative effects of model outputs. Higher reliability was observed while using SWMM model data although the maximum reliability level was same for both the cases. Likewise reliability, water utilization and spillage were found higher for SWMM output. It was also observed that, difference in reliability derived from the two models was higher for higher water demand and this was true for water utilization also. However, water spillage showed an opposite scenario. The results of the study indicate that higher runoff was obtained by SWMM model compared to rational formula may be due to using a runoff coefficient in rational formula that involves greater loss. Hence this study suggests that SWMM model ought to be used in case of community rainwater harvesting system to achieve actual runoff and for economical design.

International Conference on Recent Innovation in Civil Engineering for Sustainable Development (IICSD-2015), 2015

This study aims at depicting the present scenario of fecal sludge generation of different zones o... more This study aims at depicting the present scenario of fecal sludge generation of different zones of Dhaka city and predicting future scenarios to make people as well as the policy makers aware of the importance of fecal sludge management (FSM). It involves developing zoning maps of fecal sludge generated in different zones of Dhaka city. The dry solid volume of sludge was determined based on population using septic tanks in different zones. Volume of sludge in future was predicted up to 2035 depending on future population which was calculated using growth rate of population. Narayanganj, zone-4 and zone-7 were found to be the zones having higher fecal sludge volume compared to others. It was also found that sludge volume would be increased by about 38% and 78% on 2025 and 2035 respectively indicating importance of a sustainable fecal sludge management for the city. Finally zoning maps were developed based on fecal sludge volume reflecting present as well as future scenarios which might facilitate the policy makers to assign relative importance while planning for fecal sludge management.