Hydraulic Conductivity Study In Engineered Soil Media For Stormwater Runoff Treatment In Bioretention Facility

The conventional method of drainage system was seemed inadequate to cater urban stormwater runoff due to the drastic increment of the urban population. It was limited to the structural approach which related to hydraulic and hydrologic influence. Hence, this approach has been shifted to more holistic approaches by considering the environmental needs. The revised guidelines of Urban Stormwater Management for Malaysia (MSMA) in 2012 was introduced in-line with the current practices to tackle the urban and sub-urban stormwater issues. Bioretention is a favourable practice which mimics natural processes, integrating the sciences and engineering knowledge of hydrology, hydraulics as well as environment into one system. This research aimed to investigate the interaction between soil hydraulic parameter; mainly saturated hydraulic conductivity (Ksat) and water quality treatment performance and to benchmark Ksat based on bioretention performance. The comprehensive data set required for the study was obtained from a series of standard laboratory tests, designated column studies and field investigation. For this purpose, three (3) soil columns were constructed in Physical Laboratory and Modelling, River Engineering and Urban Drainage Research Centre (REDAC), USM. Four (4) soil configurations and one (1) hydrologic parameter were tested for soil column studies: engineered soil mixtures, media depths, compost materials, mulch layers and inflow variation. Both Ksat and pollutant concentration were examined for influent and effluent samples for each soil configuration. Two (2) field bioretention cells were constructed by applying the best treatment condition from soil column studies by the assistance of vegetation. Ksat and treatment performance data were monitored during nine (9) actual storm events as well as the application of six (6) cycles of synthetic stormwater runoff. Analysis of soil media through soil column studies showed that Ksat values achieved the recommended ranges were reduced over the time which is consistent with the literature. Besides, it is sufficient to treat physical, biochemical and nutrient contaminants from Class IV to Class II above 85% of pollutant removal through sedimentation, adsorption and filtration processes based on the comparison using ANOVA. The results of multiple linear regression (MLR) analyses indicate that removal performance of TSS, TP and other water quality parameters is a function of the Ksat relative (Krel) at most soil configurations with R2 obtained more than 0.8. The study showed that compost material is the main factor that influenced the Ksat values through the relationship between the combinations of water quality parameters. However, the relationship between both parameters varies for field studies confirming that external factors such as duration and size of bioretention, rainfall, and seasonal change had influenced the results

Mangroves As Coastal Bio-Shield: A Review of Mangroves Performance in Wave Attenuation

Mangroves have been recognized as soft structures that provide coastline protection. The capability of dampening waves helps minimize destruction from catastrophic events including erosive wave attacks, torrential storms, and tsunamis. Mangroves act as the first line of coastal defense in natural tragedies such as during the Super Typhoon Haiyan 2013 and Indian Ocean Tsunami 2004, whereby the leeward mangrove area encountered less damage than the unprotected area. This has further brought the attention of researchers to study the attenuation performance of these coastal vegetations. Based on an extensive literature review, this paper discusses the attenuation mechanism of mangroves, the factors influencing the dissipation performance, studies on mangrove dissipation via different approaches, the dissipation efficiency, mangrove conservation and rehabilitation efforts in Malaysia and implementation of mangrove as coastal bio-shield in other countries. The study highlights that mangrove parameters (such as species, width, density etc.) and wave parameters (such as wave period and incident wave height) are among the contributing factors in mangroves-induced wave attenuation, with different efficiency rates performed by different mangroves and waves parameters. Towards that end, several improvements are proposed for future research such as to incorporate all influencing dissipation factors with specific analysis for each species of mangroves, to perform validation on the studied mangroves attenuation capacity in different settings and circumstances, as well as to address the extent of protection by the rehabilitated mangroves. A systematic and effective management strategy incorporating ecological, forestry, and coastal engineering knowledge should be considered to ensure a sustainable mangroves ecosystem and promising coastline protection by mangroves. Doi: 10.28991/cej-2021-03091772 Full Text: PD

Assessment on pollutant removal of interconnected wet detention pond

Best Management Practices (BMPs) have been used worldwide to control urban stormwater runoff. The objective of this paper is to assess the urban wet detention ponds on quality control for commercial and residential development in Denai Alam, Selangor, Malaysia. Field monitoring was conducted in this study area. Eight water samples were collected at 8 different locations from upstream to downstream of catchment area. All parameters were tested on-site except for TSS which was conducted at laboratory. The value of turbidity increased due to the occurrence of erosion and the side slope of detention pond. Total suspended solid (TSS) removal efficiency of Pond B is between 13 - 24%. However, this pond did not perform well in removing total phosphorus (TP) and ammonia nitrogen (NH -N) due to low concentration of dissolved oxygen. It is indicated3that the water samples is classified under Class III of Department of Environment (DOE) Water Quality Classification which further treatment is required. Maintaining the detention pond could reduce pollutant loadings to meet targeted requirements of water quality improvement

Challenges and developments of bioretention facilities in treating urban stormwater runoff; A review

Bioretention or rain garden is a preferable low impact development (LID) approach due to its characteristics which reflect natural water cycle processes. However, this system is still little understood and quite complicated in terms of design and implementation due to many technical considerations. Hence, this paper gives a review of the challenges and developments for the use of bioretention facilities to enhance its capabilities in attenuating peak flow and treating stormwater runoff particularly in urban areas. This paper reviews the main aspects of bioretention which are stormwater hydrologic, hydraulic and treatment performance. Some of the limitations during the implementation of this natural approach are highlighted in design configuration and the public perception towards this new approach. It is concluded that the bioretention approach is one of the sustainable solutions for stormwater management that can be applied either for individual systems or regional systems

Principles and Modes of Distillation in Desalination Process

Distillation has been a very important separation technique used over many centuries. This technique is diverse and applicable in different fields and for different substances. Distillation is important in the desalination section. Various principles are used in desalting seawater and brackish water to fulfill the demands of freshwater. This work explains the modes and principles of distillation in desalination, their types, present improvement, challenges, and limitations as well as possible future improvements. The first and primary mode of distillation is the passive type. As times went by and the demand for freshwater kept increasing, other modes were introduced and these modes fall under the active distillation type. However, each mode has its own advantages, disadvantages, and limitations over each other. The principles and modes of distillation are as significant as understanding the energy sources needed for distillation. Hence, they are the basic knowledge needed for future innovation in the desalination industries

THE BEST FIT PROBABILITY DISTRIBUTION MODEL FOR THE ESTIMATION OF EXTREME RAINFALL IN LIMBANG, SARAWAK

In Malaysia, the increment of annual rainfall patterns is causing frequent floods, mainly in Sabah and Sarawak. Limbang river basin was selected as a case study due to it was facing of high-risk flooding problem mainly during the transition of climate. This study was aimed to estimate the frequency of rainfall under various return periods and to identify the best fit model probability distribution of annual maximum rainfall based on twenty-four hours sample in Limbang. The three statistical models were used, which are Gumbel, Log-Pearson type III, and Log-Normal. Based on the goodness of fit tests, Chi-Square, Kolmogorov Smirnov test, and the Log-Normal was found to be the best fit model for the station of Panduran. The Log-Pearson type III was found to be the best-fit distribution model for the rest of the stations, which occupies almost more than 90%. The maximum values of expected rainfall were calculated using the best fit probability distributions and could be used by a design engineer in the future

The Performance of Treatment Train System Incorporated with Nature-Based Materials in Capturing Nutrient for Stormwater Runoff

Biofilters, commonly called rain gardens, are becoming increasingly popular among best-management practices (BMPs). They have recently sparked significant interest due to their ability to control stormwater quality. These systems face challenges in manipulating dissolved nitrogen and phosphorus species. This study reports the results of the removal of nitrogen and phosphorus in two modified bioretention systems. The performance of modified bioretention with coconut and durian was compared. The modified bioretention system was evaluated as a single and a series. Sequencing these systems in a series maintained the continuity of nutrient removal. Both series efficiently removed NH3-N (97% in TC5, 95% in TD5), while the removal of NO3-N was moderate (65% inTC5, 67% in TD5). Good removal efficiencies of TP were observed in two series (84% in TC5, 81% in TD5). However, the PO4 removal was equalized in all series (98%). The TN and ON removal were poor and fluctuated with time and column number in TC5, the overall removal efficiencies were (69% and 43%), respectively, while in TD5 a significant fraction of TN and ON were removed (86% and 78%), respectively. As compared with coconut husk, durian peel is considered a promising material that can enhance the water quality in bioretention systems

The Common Approaches of Nitrogen Removal in Bioretention System

Bioretention is considered one of the best management practices (BMPS) for managing stormwater quality and quantity. The bioretention system has proven good performance in removing total suspended solids, oil, and heavy metals. The nitrogen (N) removal efficiency of the bioretention system is insufficient, however, due to the complex forms of nitrogen. Therefore, this paper aims to review recent enhancement approaches to nitrogen (N) removal and to discuss the factors influencing bioretention efficiency. To improve bioretention efficiency, several factors should be considered when designing bioretention systems, including nitrogen concentration, climate factors, and hydrological factors. Further, soil and plant selection should be appropriate for environmental conditions. Three design improvement approaches have been reviewed. The first is the inclusion of a saturated zone (SZ), which has been used widely. The SZ is shown to have the best performance in nitrogen removal. The second approach (which is less popular) is the usage of additives in the form of a mixture with soil media or as a separated layer. This concept is intended to be applied in tropical regions with wet soil conditions and a short dry period. The third approach combines the previous two approaches (enhanced filter media and applying a SZ). This approach is more efficient and has recently attracted more attention. This study suggests that further studies on the third approach should be carried out. Applying amendment material through filter media and integrating it with SZ provides appropriate conditions to complete the nitrogen cycle. This approach is considered a promising method to enhance nitrogen removal. In general, the bioretention system offers a promising tool for improving stormwater quality

Assessment of Land Use Land Cover Changes and Future Predictions Using CA-ANN Simulation for Selangor, Malaysia

Land use land cover (LULC) has altered dramatically because of anthropogenic activities, particularly in places where climate change and population growth are severe. The geographic information system (GIS) and remote sensing are widely used techniques for monitoring LULC changes. This study aimed to assess the LULC changes and predict future trends in Selangor, Malaysia. The satellite images from 1991–2021 were classified to develop LULC maps using support vector machine (SVM) classification in ArcGIS. The image classification was based on six different LULC classes, i.e., (i) water, (ii) developed, (iii) barren, (iv) forest, (v) agriculture, and (vi) wetlands. The resulting LULC maps illustrated the area changes from 1991 to 2021 in different classes, where developed, barren, and water lands increased by 15.54%, 1.95%, and 0.53%, respectively. However, agricultural, forest, and wetlands decreased by 3.07%, 14.01%, and 0.94%, respectively. The cellular automata-artificial neural network (CA-ANN) technique was used to predict the LULC changes from 2031–2051. The percentage of correctness for the simulation was 82.43%, and overall kappa value was 0.72. The prediction maps from 2031–2051 illustrated decreasing trends in (i) agricultural by 3.73%, (ii) forest by 1.09%, (iii) barren by 0.21%, (iv) wetlands by 0.06%, and (v) water by 0.04% and increasing trends in (vi) developed by 5.12%. The outcomes of this study provide crucial knowledge that may help in developing future sustainable planning and management, as well as assist authorities in making informed decisions to improve environmental and ecological conditions

Assessment of Land Use Land Cover Changes and Future Predictions Using CA-ANN Simulation for Selangor, Malaysia

Land use land cover (LULC) has altered dramatically because of anthropogenic activities, particularly in places where climate change and population growth are severe. The geographic information system (GIS) and remote sensing are widely used techniques for monitoring LULC changes. This study aimed to assess the LULC changes and predict future trends in Selangor, Malaysia. The satellite images from 1991–2021 were classified to develop LULC maps using support vector machine (SVM) classification in ArcGIS. The image classification was based on six different LULC classes, i.e., (i) water, (ii) developed, (iii) barren, (iv) forest, (v) agriculture, and (vi) wetlands. The resulting LULC maps illustrated the area changes from 1991 to 2021 in different classes, where developed, barren, and water lands increased by 15.54%, 1.95%, and 0.53%, respectively. However, agricultural, forest, and wetlands decreased by 3.07%, 14.01%, and 0.94%, respectively. The cellular automata-artificial neural network (CA-ANN) technique was used to predict the LULC changes from 2031–2051. The percentage of correctness for the simulation was 82.43%, and overall kappa value was 0.72. The prediction maps from 2031–2051 illustrated decreasing trends in (i) agricultural by 3.73%, (ii) forest by 1.09%, (iii) barren by 0.21%, (iv) wetlands by 0.06%, and (v) water by 0.04% and increasing trends in (vi) developed by 5.12%. The outcomes of this study provide crucial knowledge that may help in developing future sustainable planning and management, as well as assist authorities in making informed decisions to improve environmental and ecological conditions