Runoff Pollution Control Research Articles

Study on auxiliary operation control of machine learning in multiobjective complex drainage system.

Recently, urban waterlogging prevention and treatment of black-odorous rivers have become a social concern and the upgradation of drainage system and the development of river runoff pollution control projects have accelerated. The use of deep tunnels to upgrade old drainage systems and achieve pollution control-related engineering designs has complicated the drainage system operation control. The traditional operation control mainly relies on human experience or model simulation. This study provides a perspective of machine learning for controlling the operation of the drainage system and exploring whether the operation suggestions regarding facilities in this system can be given in real time while relying only on real-time data and avoiding the complex model simulation process. Herein, five drainage systems were used as examples: the initial water level of a pipeline, key point water level flow, pump station front pool water level, and most unfavorable point water level were selected as relevant variables and four machine-learning discrimination methods were used for to analyze the weir-lowering operation of a deep tunnel. This study found that the average error rate of the linear discrimination method was <10%, thereby exhibiting satisfactory performance. This study provides insights for improving the operation of complex drainage systems.

Identification and Optimization Method of Rainfall-Runoff Pollution Risk Level

Runoff pollution control is currently a difficult problem in urban water environment protection. The identification of runoff pollution risk into rivers is the key to improve the efficiency of pollution control. By combining landscape patterns and processes and using the landscape pattern index and minimum cumulative resistance model, a set of integrated methods for river rainfall-runoff pollution risk identification and optimization was proposed. The rainfall-runoff pollution pattern, process, and comprehensive risk index of the major river reaches in the study area were calculated. The risk paths of runoff pollution generated by cultivated land, urban construction land, and traffic industrial and mining land were identified as 256, 182, and 208, respectively. The results showed that:① according to the pattern factors, a ten-level rainfall runoff pollution pattern risk index was identified, and more rivers in the central and southern regions had a relatively high pollution risk. ② The risk of runoff pollution caused by fragmentation and dominance factors was higher than that caused by aggregation factors, and the range was wider. The corresponding landscape pattern optimization methods were proposed for the three types of indicators. ③ For the pollution process, the identified ten levels of rainfall runoff pollution process risk index showed that the rivers with high risk index were mainly concentrated in the central urban area and gradually decreased to the periphery. ④ The range and intensity of rainfall and runoff pollution caused by different types of land use were as follows:in terms of range, cultivated land>traffic industrial and mining land>urban construction land. Regarding intensity, traffic industrial and mining land>urban construction land>cultivated land. ⑤ The river pollution risk in the middle and southeast of the study area was significantly higher than that in the west and north of the study area. Among them, there were 13 level 1 risk reaches with a length of 209.65 km, accounting for 9.39% of the total length. There were 11 level 2 risk river sections with a length of 186.83 km, accounting for 8.37% of the total length. These river reaches should be the focus of urban rainfall runoff pollution control in the future.

Temporal and Spatial Distribution Characteristics and Source Apportionment of Runoff Pollution in Langfang City

Urban runoff pollution can carry pollutants into the receiving water through scouring and leaching, causing black color and odor or eutrophication. Understanding and mastering the characteristics of runoff pollution is a prerequisite for the effective control of runoff pollution. This study aimed to comprehensively analyze the temporal and spatial distribution characteristics of runoff pollution and the correlation between pollutants in the urban area of Langfang City. Rainfall runoff samples were collected seven times by setting up 14 sampling sites within the urban area. The suspended solids (SS), chemical oxygen demand (COD), N, P, fecal E. coli, anionic surfactants, volatile phenols, and Zn, Cr6+, As, Cu, etc. were analyzed. The source and distribution of pollutants were summarized and analyzed through principal component analysis and cluster analysis. The results showed that the concentration of pollutants in runoff in Langfang City varied greatly at different times and locations. The average ρ(SS) at each point ranged from 150-500 mg·L-1, and the average concentrations of COD, N, P, and fecal E. coli all exceeded those of the surface water standard Ⅴ. The average concentration of anionic surfactants, petroleum, and volatile phenols were between those of the surface water standard Ⅰ and standard Ⅳ. The concentrations of metal pollutants were relatively low. NH4+-N had a positive correlation with total nitrogen (TN), volatile phenols, and As. COD had a certain positive correlation with TN, total phosphorus (TP), Cr6+, and As, whereas fecal E. coli had a certain negative correlation with Zn and Cu. The organic matter, P, Cu, and SS were probably derived from vehicle tires and road surfaces. All sampling sites could be roughly divided into four types according to the features of pollution:mainly commercial service areas, residential areas, larger arterial roads, and small roads between communities. The pollution of runoff in Langfang City was relatively serious, especially that of COD, N, and P. This research provides important reference values for the control and regulation of runoff pollution in urban areas and other northern cities.

Low-Impact Development (LID) in Coastal Watersheds: Infiltration Swale Pollutant Transfer in Transitional Tropical/Subtropical Climates

The control of runoff pollution is one of the advantages of low-impact development (LID) or sustainable drainage systems (SUDs), such as infiltration swales. Coastal areas may have characteristics that make the implementation of drainage systems difficult, such as sandy soils, shallow aquifers and flat terrains. The presence of contaminants was investigated through sampling and analysis of runoff, soil, and groundwater from a coastal region served by an infiltration swale located in southern Brazil. The swale proved to be very efficient in controlling the site’s urban drainage volumes even under intense tropical rainfall. Contaminants of Cd, Cu, Pb, Zn, Cr, Fe, Mn and Ni were identified at concentrations above the Brazilian regulatory limit (BRL) in both runoff and groundwater. Soil concentrations were low and within the regulatory limits, except for Cd. The soil was predominantly sandy, with neutral pH and low ionic exchange capacity, characteristic of coastal regions and not very suitable for contaminant retention. Thus, this kind of structure requires improvements for its use in similar environments, such as the use of adsorbents in soil swale to increase its retention capacity.

Study on the Influence of Sponge Road Bioretention Facility on the Stability of Subgrade Slope

With the large-scale application of sponge city facilities, the bioretention facility in urban roads will be one of the key factors affecting the safety of construction facilities in areas with abundant rainfall. In this study, by establishing a three-dimensional finite element model for numerical analysis and combining it with geotechnical tests, the effects of bioretention facility on water pressure distribution, seepage path, and slope stability under rainwater seepage conditions are proposed. In addition, this study puts forward the relationship between the parameters of the bioretention facility and the stability of the slope in combination with the effect of runoff pollution control, which provides direction and basis for the planning, design, and construction of sponge cities in road construction.

Simulation of Urban Storm Water Runoff Control Based on Big Data

The acceleration of urbanization has brought about rapid economic development, but at the same time, it has also brought some damage to the ecological environment. The proportion of hardened area of the ground is higher and higher, and the rainwater runoff pollution caused by rainfall is more and more serious. In order to follow the sustainable development strategy, and for the more stable and high-speed economic development, the control of rainwater runoff pollution is urgent. The purpose of this paper is to simulate the urban storm water runoff control and find the most suitable scheme for storm water runoff pollution control. Because the simulation of SWMM is more accurate than other models, it can directly reflect the situation of rainwater runoff pollution, so the model selected for rainwater runoff in this paper is SWMM, and then build the model, through the collection and collation of the basic data of the study area, the generalization of the sub catchment area and drainage network is completed. Through the analysis of the characteristics of the study area, the rainwater garden and permeable pavement are determined as the scheme to control the rainwater runoff in the study area. Finally, the SWMM model is used to simulate the control effect of rainwater garden and pervious pavement on rainwater runoff pollution control. The experimental results show that the storm water garden can effectively control the impact of SS scouring effect on the environment, significantly reduce the discharge of SS, and significantly reduce the peak concentration of SS, and its ability to control SS increases with the thickness of the surface plant layer. The control ability of rain permeable brick pavement to SS increases with the increase of surface porosity, that is, the control effect of SS is the best when the porosity is 20%.

Conceptual planning approach of low impact developments for combined water quality‐quantity control at an urban scale: A case study in Southern China

AbstractManaging urban water in many cities becomes more challenging under impacts of climate change and urbanization. Low impact development (LID) measures have been increasingly recognized and applied thanks to their capability of tackling multi‐dimensional water problems associated with both quantity and quality issues. Yet, in China limited attention has been paid to guide the planning strategy of LIDs in the preliminary stage, which often suffers from inadequate and imprecise data and information. In this study, an approach integrating a GIS‐based spatial evaluation model, a fuzzy comprehensive evaluation module and a multi‐objective optimization algorithm, is proposed to prioritize the spatial distribution of LIDs (i.e., type, placement, and extent) at the subcatchment scale in a case study in Southern China. By evaluating the trade‐offs among runoff reduction, pollution control, and economic investment, the synergies, and combination strategies of four types of LIDs are explored. Knowledge gained from this study is necessary and beneficial for water planners and practitioners to improve LID planning efficiency under constrained conditions.

Performance on horizontal flow and folded plate denitrification bioreactor recycling waste sawdust and municipal sludge for continuously treating simulated agricultural surface runoff

Nitrogen removal from agricultural surface runoff is of great significance to protect the water quality and safety of groundwater and drinking water. The denitrification bioreactor uses wood-particle products and municipal sludge as solid carbon sources to treat agricultural surface runoff and the rule of total nitrogen produced by wood-particle products is still blank. In this study, a type of denitrification bioreactor with municipal sludge (MS) and Cunninghamia lanceolata sawdust (CLS) as solid carbon source to denitrify simulated agricultural surface runoff is designed. Results show that CLS can release approximately 0.86 ± 0.06 mg L−1 of nitrogen into the water, and the release process conforms to Non-Fickian transport (n = 0.46). The addition of MS is beneficial to increase the average degradation rate of NH4+-N (70.94%). Increasing the inflow rate is beneficial to increase the average degradation rate of NO2−-N, NO3−-N and TN. When the influent flow is 1.34 mL min−1, the average degradation rate of NO2−-N is as high as 61.61% while of TN is 86.04% in the CLS horizontal flow denitrification bioreactor. The average degradation rate of NO3−-N of CLS and MS (sludge-water volume ratio = 1:2) folded plate denitrification bioreactor is 95.72%, which is 17.46% higher than the horizontal flow type. Based on the principle of cleaner production, this study recycles waste CLS and MS as solid carbon sources in the bioreactor to continuously treat and simulate agricultural surface runoff. The device can not only degrade high-concentration nitrogen, but also prevent the generation of waste and waste of energy, which is a new surface runoff pollution control technology.

Construction of the sponge city regulatory detailed planning index system based on the SWMM model

Sponge city is a new generation of urban rainwater management concept, which can take into account multiple goals such as water logging prevention and control, runoff pollution control, utilization of rainwater resources, and water ecological restoration. With the pilot projects of low-impact development and sponge cities, optimizing the urban land use structure is the key to the construction and development of sponge cities. Our work aims to explore how the construction of sponge cities can be implemented in the regulatory detailed planning index system and become part of the statutory planning, which has positive significance for the construction of sponge cities. On the basis of summarizing the previous research results, we take sponge city as the starting point, through constructing the control index system from the perspective of sponge city construction, puts forward the key issues that should be solved at the control level, and uses level analysis to clarify the indicators and controls at each level categories, and construct a quantifiable and operable index system that can guide the planning and construction of sponge cities. Finally, we take the urban control planning unit as an example, put forward the concept, method and result expression requirements of the regulatory detailed planning, further verify the scientific and comprehensiveness of the above-mentioned indicator system setting; implement the construction requirements of the sponge city construction demonstration area layer by layer, to fully reflect the construction content of sponge cities in the regulatory unit, and display the results in the form of plans and other forms; at the same time, propose measures and strategies to promote the implementation of control regulations for the construction of sponge cities, and put forward prospects for future research to provide for future sponge city construction learn from ideas.

Pollutant first flush identification and its implications for urban runoff pollution control: a roof and road runoff case study in Beijing, China.

First flush is a common phenomenon in urban runoff pollution. Typical cement roof and asphalt road runoff in Beijing, China were monitored for 2 years. Based on the M(v) curve, the suspended solids (SS), chemical oxygen demand (COD), total phosphorus (TP) and particulate phosphorus in cement roof runoff presented a stronger first flush than those in asphalt road runoff. The first flush volume (VFF) of SS, COD, total nitrogen (TN) and TP in asphalt road runoff differed slightly from the cement roof. There were also differences in the first flush assessment depending on which method was used. We proposed a new method based on the runoff depth versus pollutant cumulative mass curve. According to the national standards in China (VFF = 3 mm), various masses of different pollutants, such as 91.42 ± 9.80% (cement roof) and 78.49 ± 19.41% (asphalt road) of SS and 86.85 ± 13.54% (cement roof) and 72.80 ± 25.79% (asphalt road) of COD, can be effectively controlled, but our mass control efficiencies were 55.91%-66.65% when VFF = 1 mm. The new method proposed in this study provides an alternative approach for assessing runoff pollution control efficiency of different VFF.

Comprehensive Performance Evaluation of Green Infrastructure Practices for Urban Watersheds Using an Engineering–Environmental–Economic (3E) Model

Green infrastructure practices could provide innovative solutions for on-site stormwater management and runoff pollution control, which could relieve the stress of nonpoint pollution resulting from heavy rainfall events. In this study, the performance and cost-effectiveness of six green infrastructure practices, namely, green roofs, rain gardens, pervious surfaces, swales, detention basins, and constructed wetlands, were investigated. The comprehensive performance evaluation in terms of the engineering performance, environmental impact, and economic cost was determined in the proposed engineering–environmental–economic (3E) triangle model. The results revealed that these green infrastructure practices were effective for stormwater management in terms of runoff attenuation, peak flow reduction and delay, and pollutant attenuation. It was suggested that for pollution control, detention basins can efficiently reduce the total suspended solids, total nitrogen, total phosphorus, and lead. The implementation of detention basins is highly recommended due to their higher engineering performance and lower environmental impact and economic cost. A case study of a preliminary cost–benefit analysis of green infrastructure practice exemplified by the Pearl River Delta in China was addressed. It suggested that green infrastructure was cost-effective in stormwater management in this area, which would be helpful for sustaining healthy urban watersheds.

Distribution and Health Risk Assessment of Some Trace Elements in Runoff from Different Types of Athletic Fields

Environmental risk of heavy metals and metalloids in athletic fields has raised people’s attention in the recent years. Seven trace elements, including metals and metalloids, were detected in the runoff of five typical athletic fields in the university campus under three rainfall events. Except for Cr, the total concentrations of Zn, Pb, Cu, Mn, Cd, and As in artificial turf runoff are the highest among five athletic fields, followed by that of plastic runway. The concentration and first flush effect of trace elements are followed in the order of 1st &gt; 2nd &gt; 3rd rainfall events. The strongest correlations between metals and metalloids were observed in the tennis court runoff, while the artificial turf shows the least. The release of trace elements could be directly from the surface materials and particles on the athletic field and influenced by the comprehensive factors including surface materials, rainfall events, and pollutant characters. Pollution risk assessment shows that the pollution extent of the five types of athletic field is at least “moderate” and follows the order of artificial turf &gt; basketball court &gt; plastic runway &gt; badminton court &gt; tennis court. Pb shows the highest pollution level, while Cr shows the highest healthy risk. The results can provide a theoretical basis for runoff pollution control and safety use of athletic fields.

Comparative Non-Darcian Modeling of Subsurface Preferential Flow Experimental Observations in a Riparian Buffer

HighlightsHigh ecohydrological activity drives macropore prevalence in riparian buffers.An abundance of macropore flow (MF) was confirmed in a field riparian buffer in Kenya.Source-response (SR) and multilayer kinematic diffusive wave (MKDW) MF models are compared.A novel MKDW modeling framework efficiently identifies and predicts preferential flow in riparian buffers.Abstract. The significant ecohydrological activity typical of riparian buffers makes them potential hotspots of macropores, i.e., structured preferential flow pathways, through the soil vadose zone. The prevalence of these preferential pathways can allow transported contaminants to bypass the soil matrix and quickly reach a seasonal shallow water table and the adjacent surface waterbody. This quick transport can ultimately limit the role of riparian buffers for runoff pollution control. Currently, there are no management tools that incorporate macropore flow (MF) when assessing riparian buffer performance. The objective of this study was to experimentally quantify and mathematically simulate macropore flow and arrival time in a riparian buffer under field conditions. Three infiltration experiments were conducted with a grid of 20 time-domain transmission (TDT) dielectric soil moisture sensors along a field riparian buffer transect in Kenya to quantify the presence of macropore flow and to test two non-Darcian soil MF models, including the source-responsive (SR) model and the modified kinematic-dispersive wave (MKDW) model developed in this study, by adding a user-defined multilayer convection scheme and a new hysteresis function between water flux and content. The abundance of MF in the riparian buffer was corroborated experimentally. Modeling results showed that the MKDW model was an efficient (average NSE of 0.937 and 0.721 for calibration and testing, respectively), flexible, and robust method to identify and represent non-linear and non-sequential MF signals at any soil depth and antecedent conditions. The SR model was computationally inexpensive and provided good calibration results (NSE = 0.867) but required piecemeal recalibration of the travel time and maximum water content at each layer and yielded lower performance in testing. The Akaike (AIC) and Bayesian (BIC) information criteria showed that MKDW outperformed SR when accounting for the trade-off between model complexity and efficiency. The results support further research focused on independent characterization of model parameters at the field scale, and the inclusion of MKDW in holistic riparian buffer management and decision-support tools such as VFSmod. Keywords: Kinematic-dispersive wave, Macropore flow, Numerical modeling, Preferential flow, Riparian vadose zone.

Runoff pollution control of a sewage discharge project based on green concept – a sewage runoff pollution control system

Abstract The problem of runoff pollution in sewage discharge projects mainly depends on manual inspections, and this traditional inspection method has high personnel and time costs. Moreover, with rapid development of the Internet of Things technology, application of intelligent information management has become a development trend of various neighborhoods where LoRa communication technology with low power consumption and long-distance transmission characteristics has been widely used. Therefore, starting from the concept of green environmental protection, LoRa technology is used in this paper to design and develop a runoff pollution control system including a management terminal, terminal and network components for waste-water discharge projects. The main function is to calculate and comprehensively analyze the conventional indexes such as CODCr, BOD5, ammonia nitrogen, and total phosphorus in the sewage treatment process, which reduces the calculation error of total pollutant treatment volume and total production volume, and improves the data accuracy of the sewage purification project. Meanwhile, the example verifies that the system proposed in the paper has accurate analysis of runoff pollution characteristics and accurate data calculation, which provides technical support for sustainable development and green development goals and mitigation of water crisis.

Impacts of key factors on heavy metal accumulation in urban road-deposited sediments (RDS): Implications for RDS management

Understanding of the impacts of key influential factors on RDS related heavy metal (HM) contamination is crucial for developing effective RDS management strategies to support the stormwater pollution mitigation. In this paper, three factors (i.e. traffic condition, slope of road and antecedent dry period) were considered to investigate their influences on the accumulation of RDS and adsorbed HMs. Positive correlations between truck and Zn/Ni content in RDS, car and Cu/Pb content in fine RDS, as well as bus and Cu content in coarse RDS were observed. Relative to sloping stretches, RDS from level stretches generally presented finer size distributions and aggravated HM contamination in fine fractions. Moreover, the fine RDS and adsorbed HMs increased significantly with the accumulation of RDS. Based on these findings, optimized RDS management strategies were proposed to enhance the removal of washable RDS in pollution hotspots. For example, tandem sweeping technologies, performing high efficiency in capturing fine particles, are suggested to be employed during the steady period of RDS accumulation, in order to reduce fine RDS effectively. The outcomes of this study provide useful reference for the source control of stormwater runoff pollution.

Constructing the landscape security pattern of urban stormwater in Nanjing, China

Stormwater management must address three direct threats to urban ecological security during the urbanisation of China: waterlogging, water pollution and shortages of water resources. Based on the theory of landscape security patterns, macro-level stormwater landscape security patterns (SLSPs) associated with regional flood security, runoff pollution control security structures and water resource utilisation can be set up to solve urban stormwater and environmental problems. The objective of this study was to construct the SLSP of the Tiebei area in Nanjing, east China. A high-precision digital terrain model and a digital orthophoto map were obtained using portable, unmanned aerial vehicle remote sensing technology and Pix4Dmapper software. These data were integrated in an ArcGIS platform and used to calculate runoff flow direction and flow accumulation, measure runoff pollution levels and determine priority areas for water resources protection. Combined with regional planning of the Tiebei area, the SLSP was effectively and efficiently constructed. This study also examined current management and use of urban stormwater and addressed the important bases for ecological flood prevention, regional planning and site design of the urban landscape.

The characteristics of rainfall runoff pollution and its driving factors in Northwest semiarid region of China - A case study of Xi'an

With the effective control of point source pollution, rainfall runoff pollution has become the main source of water pollution in Xi'an. Understanding the characteristics and driving factors of rainfall runoff pollution would provide theoretical foundation for urban rainfall runoff pollution control. In this study, a total of 32 rainwater samples, 604 roof runoff samples and 608 road runoff samples obtained from literature and a total of 35 rainwater samples, 127 roof runoff samples and 70 road runoff samples collected by our group were mixed to analyze the rainfall runoff pollution from 2008 to 2019. The Mann-Kendall and Logarithmic Mean Divisia Index (LMDI) method were used to determine the trend of pollution and the driving factors of water quality changes. The results showed that the major pollutant from rainwater was nitrogen, while the main pollutants from roof and road runoff were COD and SS. The rainwater quality during the study period was “clean to slightly polluted”. The roof runoff quality of most years (67%) was “clean to slightly polluted”. The road runoff quality was poor: 22% was “moderately polluted”, and 45% was “heavily polluted”. The concentration of pollutants except COD in rainwater showed a decreasing trend, while the trend of pollutants in roof and road runoff was not completely consistent with that in rainwater. NH3-N showed strong positive correlation with TN in roof runoff, which indicated common sources of these pollutants. There was a significant correlation between SS and COD in road runoff, and between SS and TP in roof runoff, suggesting SS was an important carrier of COD and TP. Technology innovation was the dominant factor affecting water quality, followed by industrial structure. Economic development and population scale contribute negatively to water quality improvement, and there was a sharp increase in the population scale effect in 2017.

Research on Design Method Optimization of Combined Sewer Overflow Detention Tank

Detention tank is widely used in urban waterlogging control, rainwater runoff pollution control, combined sewer overflow (CSO) control and rainwater utilization, etc. For detention tanks in different types or functions, their design methods, construction forms and ways of operation and management are very different. In recent years, many cities in China have begun to apply or plan to build CSO detention tanks to control the CSO pollution, but there are still many problems and puzzles in designing the tank. This paper summarizes and evaluates the common design methods of CSO detention tank at China and abroad. Based on the physical projects in which the author has participated in, the scale and control effect of the CSO detention tank are studied by model simulation, taking a combined sewer system catchment in the Beijing old city as examples. Based on the analysis, the long-term simulation method is recommended for designing of CSO detention tanks in China, and a design criteria suitable for a larger range can be determined through research and analysis of a typical and representative area if there is no way to research every area. At last, several key factors that affect greatly the scale and pollutant control efficiency of CSO detention tank are summarized and analyzed, including objectives of CSO control, rainfall characteristics, CSO pollutants transport law, interception multiple, capacity of wastewater treatment plant, space conditions and investment, layout of detention tank and operation mode of detention tank. Hope to provide reference for the scientific designing of CSO detention tank and realize cost-effectively controlling CSO in cities of China.

Design of urban runoff pollution control based on the Sponge City concept in a large-scale high-plateau mountainous watershed: a case study in Yunnan, China

Abstract China recently commenced the Sponge City initiative for the effective management of urban stormwater runoff. Numerous studies have been carried out to evaluate the cost-effectiveness of low impact development (LID) practices in Sponge City planning and implementation. However, most of the studies were at the site- or subcatchment scale, and few were conducted at the watershed scale, given the dramatically increased routing complexity and number of decision variables. This study demonstrates the cost-effective Sponge City planning process for a 25.90 km2 high-plateau watershed in southwest China. The Stormwater Management Model was coupled with the System for Urban Stormwater Treatment and Analysis Integrated (SUSTAIN) model to perform both continuous simulations and watershed-level optimization analyses, using the reduction of 85% annual runoff volume as the optimization target. Based on over 11,000 optimization runs, a near-optimal aggregated LID scenario was identified for each subcatchment. The aggregated LID size was first converted into a generic LID storage volume for individual subcatchments, and the storage volume was then disaggregated into site-level LID layouts regarding specific site conditions. The disaggregated LID layout yielded an annual average runoff volume reduction of 87.61% and close to 85% reduction for the annual average total suspended solids, total nitrogen, and total phosphorus loads. The systematic approach outlined in this study could be used for watershed-level Sponge City planning and implementation analyses in other cities.

Nutrient removal from urban stormwater runoff by an up-flow and mixed-flow bioretention system.

Bioretention is one of the most popular technical practices for urban runoff pollution control. However, the efficiency of nutrient removal from urban stormwater runoff by bioretention systems varies significantly. To improve the nutrient removal performance, innovative up-flow and mixed-flow bioretention systems were proposed in this study, and a laboratory study was conducted to investigate the runoff retention and nutrient removal performance. During the leaching experiment using tap water as the inflow, turbidity, chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) leaching phenomenon was obvious. COD and TN leaching controls were obviously improved when the up-flow and mixed-flow bioretention systems were adopted comparing with the conventional bioretention. During the semi-synthetic runoff experiments, after the leaching experiments' performance (accumulated 2.78 times of empty bed volume), there were no significant differences in COD mass removal efficiencies of conventional and up-flow bioretention processes (p > 0.05); however, the COD mass removal efficiencies of the mixed-flow bioretention processes increased by 10% when compared with conventional bioretention. The TN mass removal efficiencies of the up-flow and mixed-flow bioretention increased obviously from 17% ± 13% (conventional) to 41% ± 23% (up-flow) and 31% ± 16% (mixed-flow). However, there were no significant differences in TP mass removal or runoff reduction among the three bioretention columns (p > 0.05). Both up-flow and mixed-flow bioretention can effectively improve TN mass removal, and the mixed-flow bioretention did not show a better TN removal performance than the up-flow bioretention because these two bioretention had almost the same volume of the saturated zone. Overall, the results indicate the mixed-flow bioretention proposed in this study can effectively improve TN mass removal and slightly improve COD mass removal relative to conventional methods via increases in hydraulic retention time and in-flow paths, respectively.