Sewage Markers as Determinants to Differentiate Origins of Emerging Organic Pollutants in an Urban Sri Lankan Water Drainage Network

Urban sanitation is a major challenge during the rapid urbanization being experienced by developing countries, as a low sewerage infrastructure capacity and irregular onsite wastewater treatment raise the risk of surface water contamination. The application of specific sewage markers to characterize contaminant sources is therefore essential for managing urban sanitation issues. In this study, we investigated the concentrations of eight sewage markers (acetaminophen, caffeine, carbamazepine, cotinine, sulfamethoxazole, sulfapyridine, atenolol, and acesulfame) in various water sources within urban area of the Galle City, Sri Lanka. The total concentration of the eight markers was in the order of hospital discharge > sewage treatment plant (STP) influent > surface drainage system. Among the eight selected markers, acetaminophen was dominant in hospital discharge (70.2–123.6 µg/L) while caffeine was the largest contributor to STP influent (16.2–68.7 µg/L) and surface drainage (0.95–21.73 µg/L). We then proposed and tested a set of criteria for evaluating the applicability of markers, including removal efficiency, concentration magnitude, excretion rate, and wastewater burden. The labile markers caffeine and acetaminophen were suitable for characterizing domestic gray and black wastewater, respectively. These results imply that the city’s drainage system receives both domestic graywater and human excretion, likely due to insufficient on-site sanitation systems. The conservative marker carbamazepine was useful for tracking hospital residues over long distances; these results imply that hospital wastewater treatment was not working properly, accounting for pharmaceutical residues reaching surface water via a hidden discharges connected to the drainage system.

Analisis Tren Perubahan Intensitas Hujan (Studi Kasus: Jakarta dan Bogor)

Rainfall intensity and drainage channel capacity are the main inputs in flood management infrastructure planning. The Intensity-Duration-Frequency (IDF) curve in a region has a different pattern from other regions. This study examines the temporal distribution pattern of rain and the IDF curve with case studies of the Jakarta and Bogor, represented by Kemayoran Rainfall Station and Citeko Rainfall Station, respectively. This study compared data analysis from the above stations with the ABM Method, Modified Mononobe, Indonesian National Standard for Calculating Flood Discharge, and Indonesian National Standard for Road Surface Drainage Design. The analysis results showed that the rainfall event in the Jakarta and Bogor areas was dominated by events of ≤ 4 hours with the highest percentage of rainfall volume at the beginning of the event (at the first two hours of the event). The observed hourly rainfall data has a significant difference pattern with the rainfall distribution calculated using the ABM and Modified Mononobe methods. The IDF curve obtained from the Base Curve on the Indonesian National Standard for Road Surface Drainage Design gives higher results than the IDF curve of the observation data. Meanwhile, the IDF curve calculated using the Mononobe Equation gives lower results than the IDF curve of the observation data. This study shows that standard design of rainfall duration and rainfall intensity for drainage infrastructure planning and flood management need to be continuously developed based on the latest observational data with better temporal and spatial resolution. Continuous effort in improving codes and design standard needs to be conducted to respond to climate change challenges, dynamic regional developments, and the increasing trend of flood events in Indonesia.

The Relevance of Grated Inlets within Surface Drainage Systems in the Field of Urban Flood Resilience. A Review of Several Experimental and Numerical Simulation Approaches

Urban drainage networks should be designed and operated preferably under open channel flow conditions without flux return, backwater, or overflows. In the case of extreme storm events, urban pluvial flooding is generated by the excess of surface runoff that could not be conveyed by pressurized sewer pipes, due to its limited capacity or, many times, due to the poor efficiency of surface drainage systems to collect uncontrolled overland flow. Generally, the hydraulic design of sewer systems is addressed more for underground networks, neglecting the surface drainage system, although inadequate inlet spacings and locations can cause dangerous flooding with relevant socio-economic impacts and the interruption of critical services and urban activities. Several experimental and numerical studies carried out at the Technical University of Catalonia (UPC) and other research institutions demonstrated that the hydraulic efficiency of inlets can be very low under critical conditions (e.g., high circulating overland flow on steep areas). In these cases, the hydraulic efficiency of conventional grated inlets and continuous transverse elements can be around 10–20%. Their hydraulic capacity, expressed in terms of discharge coefficients, shows the same criticism with values quite far from those that are usually used in several project practice phases. The grate clogging phenomenon and more intense storm events produced by climate change could further reduce the inlets’ performance. In this context, in order to improve the flood urban resilience of our cities, the relevance of the hydraulic behavior of surface drainage systems is clear.

Use of Bioluminescence for Monitoring Brown Coal Mine Waters from Deep and Surface Drainage

Open-pit mines can cause environmental changes, such as alterations of landscape structure, hydrology, air quality, and river sediments; they can also generate cones of depression. We propose a new method for surveys of mine waters using the example of an open-pit mine in central Poland. This study examines the correlations between bioluminescence and the color of brown coal mine waters and tests whether values of the three-color coordinate system reflected the physicochemical quality of mine waters measured in real-time and in the field. Our results show that alkalinity, pH reaction, and conductivity are higher in surface drainage, while values of trophic parameters (soluble reactive phosphates, total phosphorus, nitrates) are greater in samples representing subsurface drainage. Correlation analysis of bioluminescence with mine water quality parameters showed that only water color had a strong association with bioluminescence. This correlation is stronger for surface drainage, than for mine waters from subsurface drainage. Direct measurement of bioluminescence, resulting from adenosine 5`-triphosphate (ATP) using a luminometer, is a fast and reliable method for evaluation of the characteristics of mine waters in real-time.

Geographic Location System for Identifying Urban Road Sections Sensitive to Runoff Accumulation

This paper concerns the design of a geographic location system to identify urban road sections susceptible to runoff accumulation through the analysis of the efficiency of surface drainage networks. To this end, a combination of Geographic Information Systems (GISs) and stormwater models was proposed. First, GIS hydrology tools were employed to generate all the information required to characterise urban catchments geometrically. Then, a synthetic storm was created from precipitation data obtained through spatial interpolation for a given return period. Finally, the three main hydrological processes occurring in catchments (precipitation loss, transformation and routing) were simulated using the Hydrologic Modeling System (HEC-HMS). The system was tested through a case study of an urban catchment located in the city of Santander (Spain). The results demonstrate its usefulness in detecting critical points in terms of runoff accumulation, according to the efficiency of the existing surface drainage network.

Simulation of surface runoff control effect by permeable pavement

Permeable pavement (PP) can be used to decrease urban surface runoff. However, few studies have been conducted to explore the runoff reduction effect of various structures of PP in the carriageway. In this study, several structures of PP used in the carriageway of sponge cities in China were investigated and divided into three types: surface drainage, base course storage and drainage, and fully permeable. Then, the runoff models were developed by Storm Water Management Model to simulate the effect of the three types under various rainfall recurrence periods. Results show that rainfall recurrence period, structure and thickness of the permeable layer were identified as the most influential factors in PP runoff reduction. The surface drainage can reduce total runoff depth and coefficient by more than 14%, and also delay runoff start time and duration by more than 40 minutes. Surface runoff in the base course storage and drainage can only be generated when recurrence period is 50 years. The fully permeable does not generate any runoff under all recurrence periods. Based on simulation results, a series of runoff coefficient values for PP were recommended to help the design and implementation of PP in mitigating urban waterlogging problems.