Assessment of the Feasibility of Permeable Pavement for Sustainable Stormwater Management Using SWMM

The advancement of urbanization in the Philippines changed natural lands into impervious surfaces and aided the contamination of surface runoff and nearby water bodies. Low Impact Development (LID) technologies were introduced as an alternative to conventional drainage systems, specifically permeable pavements. Such technology is beneficial for stormwater runoff reduction, ground infiltration enablement, and stormwater treatment. This research was conducted to investigate the feasibility of permeable pavement for sustainable stormwater management in a university setting, particularly in De La Salle University – Laguna Campus. The Storm Water Management Model (SWMM) was utilized to simulate different rainfall scenarios on selected little to no vegetation regions with increasing permeable pavement area coverage. The findings showed that the LID surface area to subcatchment area (SA/CA) ratio is inversely proportional to the total runoff reduction observed in all rainfall scenarios. The total runoff reached zero when the SA/CA ratio was at least 50%. The permeable pavement was concluded to be effective in surface runoff infiltration, reduction, and storage which is beneficial for long-term stormwater management and flood prevention strategies. The study can be used in future investigations and applications of similar LID technologies

Modeling the Hydrologic Performance and Cost-Effectiveness of LID in a Residential Park Area Using a Decentralized Design Approach

Low Impact Development (LID) is one of the current research interests toward green infrastructures and urban flood control that have the capability to return developed watersheds to pre-development hydrological conditions, bringing numerous water quantity and quality benefits, while being cheaper than their traditional counterparts. However, there is a current research gap about LIDs within tropical regions. This study aims to evaluate the cost efficiency of LID scenarios in varying surface areas through a cost-effectiveness (C/E) analysis and to assess flow reduction and infiltration improvement of the cost-effective LID scenarios using US EPA Stormwater Management Model (SWMM) in a tropical residential catchment receiving an annual rainfall of 1780.5 mm (70.1″), under a Type 1 Philippine Climate. Results have shown that the Weibull plotting position generated the largest rainfall amounts. A total of 2112 manually simulated LID scenarios were modeled to obtain the cost-effective or optimal LID scenarios, where they can generate a maximum of 38.67% flow reduction and 29.73% peak flow reduction, all observed in the multiple LID scenarios. At high rainfall amounts, the multiple LID scenarios can also peak at a 1113% increase in total infiltration in the given sub-catchments. Determining the target capture goal, applicable LID types, and cost estimations from a pilot project are vital components in the future application of LIDs in these regions

Modeling the Hydrologic Performance and Cost-Effectiveness of LID in a Residential Park Area Using a Decentralized Design Approach

Low Impact Development (LID) is one of the current research interests toward green infrastructures and urban flood control that have the capability to return developed watersheds to pre-development hydrological conditions, bringing numerous water quantity and quality benefits, while being cheaper than their traditional counterparts. However, there is a current research gap about LIDs within tropical regions. This study aims to evaluate the cost efficiency of LID scenarios in varying surface areas through a cost-effectiveness (C/E) analysis and to assess flow reduction and infiltration improvement of the cost-effective LID scenarios using US EPA Stormwater Management Model (SWMM) in a tropical residential catchment receiving an annual rainfall of 1780.5 mm (70.1″), under a Type 1 Philippine Climate. Results have shown that the Weibull plotting position generated the largest rainfall amounts. A total of 2112 manually simulated LID scenarios were modeled to obtain the cost-effective or optimal LID scenarios, where they can generate a maximum of 38.67% flow reduction and 29.73% peak flow reduction, all observed in the multiple LID scenarios. At high rainfall amounts, the multiple LID scenarios can also peak at a 1113% increase in total infiltration in the given sub-catchments. Determining the target capture goal, applicable LID types, and cost estimations from a pilot project are vital components in the future application of LIDs in these regions

Stormwater Harvesting from Roof Catchments: A Review of Design, Efficiency, and Sustainability

Roof runoff is collected rainwater from a roof using a rainwater harvesting system (RWHS). The construction of an efficient RWHS requires a thorough analysis of the rainwater quality and the appropriate treatment process for its intended use. In line with this, a bibliometric and comprehensive review of studies related to roof rainwater harvesting was conducted. A corpus of 1123 articles was downloaded from the Scopus database and parsed through the CorText Manager to determine the relationships between keywords, journals, and topics related to rainwater harvesting. A comprehensive analysis was also conducted to determine the different designs of RWHS, the quality of harvested rainwater from roof catchments, the efficiency of the system for specific purposes, and its sustainability in terms of economic, environmental, and social aspects. Results show that the effectiveness of a RWHS heavily depends on its installation site, the physicochemical characteristics of the harvested rainwater, and the acceptability of the end users. An effective water treatment process is essential for achieving better water quality for harvested rainwater. Moreover, assessing the financial viability and return on investment of an RWHS is necessary

Assessment of aeration pond operation in a constructed wetland receiving high nitrogen content wastewater from livestock area

This study was performed to assess the operation conditions in the aeration pond (AP) of the surface flow constructed wetland (CW). The AP was employed to provide oxygen supply to the CW at alternating 3 h on and off. Batch test and prototype lab-scale test experiments were conducted in the laboratory to determine oxygen transfer coefficient (KLa) and oxygen consumption rate (qO2CX) values using samples from the AP. Field test monitoring was also performed to determine the water quality changes in the AP. Based on the field test monitoring, the effluent DO from the AP was increased by almost 20% due to the aeration. The KLa(20°C) and qO2CX values obtained from the field tests were relatively higher in comparison with the values reported from other wastewater treatment technologies signified an increase in oxygen transfer in the AP. Findings showed that the AP is operating with high KLa and low qO2CX which resulted to high cost in aeration system operation. Consequently, it is suggested that non-aeration time could be increased more than the aeration operation time of 3 h. © 2018 Desalination Publications. All rights reserved

Evaluation on the suspended solids and heavy metals removal mechanisms in bioretention systems

Application of bioretention systems in Korea is highly considered due to its minimal space requirements, appropriateness as small landscape areas and good pollutant removal and peak hydraulic flow reduction efficiency. In this study, the efficiency of two lab-scale bioretention types having different physical properties, media configuration and planted with different shrubs and perennials was investigated in reducing heavy metal pollutants in stormwater runoff. Type A bioretention systems were planted with shrubs whereas type B were planted with perennials. Chrysanthemum zawadskii var. latilobum (A-CL) and Aquilegia flabellata var. pumila (A-AP) respectively were planted in each type A bioretention reactors while Rhododendron indicum linnaeus (B-RL) and Spiraea japonica (B-SJ), respectively were planted in each type B bioretention reactors. Results revealed that the four lab-scale bioretention reactors significantly reduced the influent total suspended load by about 89 to 94% (p \u3c 0.01). Type B-RL and B-SJ reactors reduced soluble Cr, Cu, Zn, and Pb by 28 to 45% that were 15 to 35% greater than the soluble metal reduction of type A-CL and A-AP reactors, respectively. Among the pollutants, total Cr attained the greatest discharged fraction of 0.52-0.81. Excluding the effect of soil media, total Pb attained the greatest retention fraction in the bioretention systems amounting to 0.15-0.34. Considering the least discharge fraction of heavy metal in the bioretention system, it was observed that the bioretention systems achieved effectual reduction in terms of total Cu, Zn and Pb. These findings were associated with the poor adsorption capacity of the soil used in each bioretention system. The results of this study may be used for estimating the maintenance requirements of bioretention systems. © 2019 Techno-Press, Ltd

First Flush Stormwater Runoff in Urban Catchments: A Bibliometric and Comprehensive Review

First flush is a phenomenon in stormwater runoff that has been considered a topic of great interest in the field of nonpoint source pollution. Despite several attempts to define the first flush quantitively, the specified characteristics of the phenomenon vary among sources. To address these uncertainties, a bibliometric and comprehensive review on published articles related to first flush was conducted. A corpus of 403 research articles was obtained from the Scopus database, which was then parsed using the CorText Manager for the bibliometric analysis. The study examined quantitative definitions of first flush from various sources; climate and topographic characteristics of monitoring and experimental sites where the studies on first flush were performed; the sample collection methods applied; the first flush values obtained on the studies and how it influenced the nonpoint source pollution in urban watersheds. A network map, two contingency matrices, and a Sankey diagram were created to visualize the relationship of significant keywords related to first flush, as well as their co-occurrences with journals, countries, and years. It was found that the strength of the first flush effect could vary depending on the geographical location of the site, climatic conditions, and the pollutants being analyzed. Therefore, initial rainfall monitoring, runoff sampling, and water quality testing were seen as critical steps in characterizing the first flush in urban catchments. Furthermore, the characterization of first flush was found to be significant to the selection of best management practices and design of low-impact development (LID) technologies for stormwater runoff management and nonpoint source pollution control

Nutrient concentration in sediments accumulated in pre-treatment basins of urban LID technologies

In this study, the contribution of pre-treatment basins of low impact development (LID) technologies to nutrient reduction performance was evaluated by understanding the distribution of nutrient in sediments accumulated in each system. The captured sediments were mostly silt to medium sand ranging from 9% to 92% of the sediments collected. Greater average N and P concentrations were found in silt particles amounting to 345 mg/kg and 696 mg/kg, respectively compared to sand and gravel. Although, N concentrations in accumulated sediments were found to be highly variable at different particle sizes (CV: 0.24 to 0.77) compared to P concentration (CV: 0.08 to 0.36) attributed to effective P treatment mechanism through deposition compared to complex nitrogen removal mechanisms. In addition, the difference between N and P concentrations of sediments collected in the pre-treatment basins of LID technologies and in-situ soil was attributed to the continuous pollutant input to the LID technologies during storm events. The study proved that pre-treatment basins of stormwater LID technologies reinforced the nutrient removal performances through sediment retention. The findings of this research may be used to design pre-treatment basins of LID technologies considering nutrients as a limiting factor. © IWA Publishing 2019 Water Science & Technolog