Drainage Pipes Research Articles

Composition, antibiotic resistance, and virulence analysis of microbiota in dormitory drain pipes.

Dormitory washbasins can breed microorganisms that produce odorous gases, polluting the indoor environment. We utilized metagenome sequencing to analyze the microbiota of 40 samples from the drain pipes of dormitory washbasins. Our study aimed to investigate the microbial community structure, antibiotic resistance genes, and virulence factors, and to identify potential influencing factors such as gender, hometown, frequency of hand sanitizer usage, and number of dormitory residents. The analysis revealed 12 phyla and 147 genera, with Proteobacteria and Actinobacteria being the dominant phyla, and Mycobacterium and Nakamurella being the dominant genera. We found that the factors influencing the microbial community structure of the dormitory washbasin drain pipe are complex. The investigated factors have a slight influence on the drain pipe microbial community, with gender exerting a discernible influence. The annotation results revealed the presence of various virulence factors, pathogenic toxins and antibiotic resistance genes, including 246 different toxin types and 30 different types of antibiotic resistance genes. In contrast to the observed differences in microbial composition among samples, the distribution of resistance genes shows relatively small changes among samples. Antibiotics should be a contributing factor in the overall increase of antibiotic resistance genes in drain pipes. Overall, our study provides important insights into the community structure and function of microorganisms in dormitory drainage systems, and can guide efforts to prevent and control microbial pollution.

Research on the dismantling of double-arch tunnel after long-term service—the case study of Huangmeishan Tunnel demolition project

Mountain tunnel structures are subject to a variety of diseases with increasing service life. Earlier tunnels may need to be demolished and expanded because of the poor serving capacity. But few studies of tunnel demolition projects are available. Based on the demolition project of Huangmeishan Tunnel, this paper discusses the demolition scheme of the double-arch tunnel, calculates the stability of the slope, and investigates the defects and material performance in the tunnel. The water leakage in the tunnel mainly occurred at the mid-partition wall and the drainage pipe was clogged severely. The largest width of the crack detected is 15 mm. Material performance tests indicated that the concrete material strength exceeded the design values. In the loading test, the largest displacements of the tunnel arch and haunch were 1.73 and 1.32 mm, which verified the safety of heavy vehicles in construction. Finally, suggestions are given to avoid similar phenomena in other tunnels during the design, construction, and operation phase. The novelty of this study lies in its comprehensive analysis of a tunnel demolition project. The findings of this study contribute to enhancing the knowledge and understanding of tunnel demolition and support the safe and efficient execution of future demolition projects.

A Pipeline Defect Instance Segmentation System Based on SparseInst.

Deep learning algorithms have achieved encouraging results for pipeline defect segmentation. However, existing defect segmentation methods may encounter challenges in accurately segmenting the complex features of pipeline defects and suffer from low processing speeds. Therefore, in this study, we propose Pipe-Sparse-Net, a pipeline defect segmentation system that combines StyleGAN3 to segment the complex forms of underground drainage pipe defects. First, we introduce a data augmentation algorithm based on StyleGAN3 to enlarge the dataset. Next, we propose Pipe-Sparse-Net, a pipeline segmentation model based on SparseInst, to accurately predict the defect regions in drainage pipes. Experimental results demonstrate that the segmentation accuracy of this model can reach 91.4% with a processing speed of 56.7 frames per second (FPS). To validate the superiority of this method, comparative experiments were conducted against Yolact, Condinst, and Mask R-CNN, and the model achieved a speed improvement of 45% while increasing the accuracy by more than 4%.

Ingestion of microplastics and microfibers by the invasive blue crab Callinectes sapidus (Rathbun 1896) in the Balearic Islands, Spain

The blue crab Callinectes sapidus Rathbun, 1896 is native to the western coasts of the Atlantic Ocean and is currently considered an invasive species in the Mediterranean Sea. In this study, we examined the stomach contents of C. sapidus to determine the frequency of occurrence of microplastics (MPs) and microfibers (MFs) in the Balearic Islands archipelago in the western Mediterranean Sea. A total of 120 individuals were collected from six locations between 2017 and 2020. Overall, 65.8% of the individuals had MPs and/or MFs particles with an average of 1.4 ± 1.6 particles ind.−1 of which an average of 1.0 ± 1.3 items ind.−1 were MFs and an average of 0.4 ± 0.8 items ind.−1 were MPs. In terms of type, fragments were the dominant type of MPs and the most common size of items ranged from between 0.5 and 1 mm (40%) followed by 1–5 mm (31%). The most prevalent polymers were low-density polyethylene (39%) and high-density polyethylene (26%). In terms of links to human activities, MP ingestion was positively correlated with an increase in drain pipes, whereas MF ingestion was positively correlated with an increase in sewage pipelines, providing evidence of potential sources and the bioavailability of these particles in various environments. This study confirms the widespread presence of MP and MF particles, even in areas that are currently managed under different protection statuses, in the stomach contents of invasive blue crab species throughout coastal communities.

Current Situation of Drainage Pipe Network in China and its Detection Technology: a Brief Review

Current Situation of Drainage Pipe Network in China and its Detection Technology: a Brief Review

Comprehensive Assessment Procedure for Metropolitan Drainage Pipe Network Considering Key Nodes

Comprehensive Assessment Procedure for Metropolitan Drainage Pipe Network Considering Key Nodes

Nitrogen leaching under alternative forages grazed by sheep

Sheep farmers can increase production levels as a means to improve economic outcomes. However, this intensification can potentially result in more nitrogen (N) leaching which is at odds with the increasing pressure on farmers to reduce the quantity of N lost into the environment. Therefore, there is increasing interest in the use of alternative forages, such as Italian ryegrass and plantain, which could potentially allow farmers to increase production while decreasing N leaching. This study quantified and compared the quantity of N leaching under sheep grazing four different forages: perennial ryegrass/white clover (RGWC), Italian ryegrass/WC (IRWC), plantain/WC (PWC) and a winter brassica. Five replicates of each forage were established on plots of 800 m2 (40 m x 20 m). Each plot had an independent mole-pipe drain system with tipping-bucket monitoring equipment at the end of the pipe drain. Drainage volume and N concentrations (nitrate-N: NO3⁻-N; ammonium-N; total-N) in drainage water were measured to estimate N losses. The forages were grazed according to the best management practice for each forage type over a two-and-a-half-year period (Year 1: July-December 2019; Year 2: January-December 2020; and Year 3: January-December 2021). In the first two years of this study, NO3⁻-N leaching losses under IRWC and PWC were very small (ranging from 0.4 to 0.5 kg N/ha), and they were not different (P > 0.05) from those under RGWC. However, in Year 3, the leaching losses under IRWC and PWC treatments were greater (P < 0.05) than those under RGWC. This increased leaching was probably due to the need to re-establish these pastures. As part of renewing these swards, the IRWC and PWC plots were fallow during the key late summer-autumn period. In contrast, NO3⁻-N leaching losses under brassica forages (3.5–6.4 kg N/ha) were greater (P < 0.05) than under RGWC (0.5–1.5 kg N/ha). Overall, the leaching losses measured under sheep grazing the forages were much smaller than those commonly reported by dairy studies.

Efficient desalination method using a subsurface drainage pipe with rice husk in paddy fields

The 2011 tsunami from the Great East Japan Earthquake caused severe soil salinization in agricultural lands. Soil salt removal using a subsurface drainage pipe with rice husk has been widely used in many paddy fields. However, desalination was frequently decided based on the expertise of construction contractors in Japan resulting in inefficient desalination methods that led to a significant wastage of freshwater resources and a long duration for agricultural restoration. Previous studies have either simulated conventional subsurface drainage without considering the rice husk zone or focused only on rice husk subsurface drainage systems excluding pipes. However, no quantitative research on a subsurface drainage pipe with rice husk has been conducted using numerical simulations. Accordingly, this study proposes highly efficient desalination methods for reducing freshwater wastage using an indoor experiment and numerical simulation. The indoor experiment of the subsurface drainage pipe with rice husk was set up in a soil tank of 900 × 200 × 900 mm (length × width × height), with reproduced salinization using NaCl solution inundation and soil desalination using freshwater. Thereafter, calibration and validation using HYDRUS-2D confirmed the model's accuracy in reproducing the movement of water and salt in the soil profile. The effects at a ponding water depth of 50–300 mm under various conditions on desalination efficiency and leaching water quantity were simulated. The results suggested that as the same desalination effect is achieved, low ponding water depths with multiple desalting cycles will reduce the quantity of leaching water. Moreover, under low ponding water depth conditions, prolonging the flooding duration will cause a decrease in the desalination effect. In addition, for the same quantity of leaching water, increasing the pipe burial depth is more beneficial to desalination than expanding the rice husk zone width. This study provides theoretical guidance for water conservation and high-efficiency desalination using the subsurface drainage pipe with rice husk for post-disaster early restoration of paddy fields.

Experimental study on mix proportion optimization of anti-calcium dissolution shotcrete for tunnels based on response surface methodology

Aiming at the issue of crystallization and blockage of drainage system due to the massive calcium loss from the tunnel shotcrete, a self-designed tunnel seepage crystallization modelling system was developed. This system was produced in conjunction with the initial tunnel support shotcrete construction and drainage pipe installation, and is capable of simulating both the seepage process of groundwater in the shotcrete and the process of crystallization in the drainage pipe. Based on three different mechanisms of anti-crystallization, which include absorbing free calcium, reducing the porosity and increasing hydrophobicity, antialkali agent, nano-calcium carbonate, and silane were selected to test, respectively. Firstly, the suitable dosing ranges of these three external admixtures for resisting calcium loss in shotcrete were determined by single factor tests, which were 7%–11%, 4%–8%, and 0.3%–0.5%, respectively. Thereafter, the response surface method was employed to evaluate the interaction of antialkali agent, nano-calcium carbonate and silane on calcium loss in shotcrete, and to establish the relationship between them, and thus to determine the admixture ratio that can effectively reduce calcium loss crystallization in shotcrete, with the optimal admixture amounts of antialkali agent being 9.242%, nano-calcium carbonate 4.889% and silane 0.366%. Lastly, the reliability of the model test results was verified by the microscopic analysis, and the results showed that the total amount of calcium dissolution in the optimized group could be reduced by 75% compared with the blank control group, and was basically consistent with that derived from the response surface regression model, validating the high accuracy of the buildup response surface regression model. The present study can provide some ideas and references for reducing the seepage crystallization behavior of groundwater in the initial tunnel support shotcrete.

Impact analysis of repeated improper treatment of bridge site slopes to bridge across

The bridge site slope in Zhengjiawan has been renovated several times in response to the adverse geological conditions of the Zhengjiawan ancient landslide (ZAL) in China. However, improper control and treatment measures have caused the structural failure of the Zhengjiawan bridge (ZB). Based on long-term field monitoring data of rainfall, temperature, bridge deformation, and bridge site slope displacements, this paper analyses the impact of repeated improper treatment on bridge site slopes to bridge across. Furthermore, it summarized the interrelationship between bridge deformation and bridge site slopes under natural rainfall and improper treatment measure conditions, and proposed a set of solutions for bridge site slope control and treatment. The results show that the destruction of ZB is primarily attributed to the deformation of ZAL, natural rainfall is the main trigger controlling the intermittent creep of the ZAL, while the construction of anti-slide pile and deviation rectification of bridge abutment result in significant deformation of ZAL. The deformation of ZB and ZAL were synchronous, and the monthly displacement difference ranged from 0.18 to 5.19 mm. The failure of the ZB structure resulting from the ZAL is attributed to the insufficient shear strength of the weak loose soil comprising the landslide, which fails to withstand the sliding force induced by continuous heavy rainfall. Additionally, the original anti-slide pile inadequately controls the deformation of the landslide. By setting the second-row anti-slide pile, adding the cross-sectional area of the bridge pier foundation, and installing drainage pipes, the safety of the bridge is effectively guaranteed. The control and treatment of ZAL show that preventing bridge pier deformation should be prioritized followed by controlling and treating bridge site slopes, and this study provides insights into interactions between unstable landslide treatments and bridge structures which may serve as a reference for similar projects.

Research on intelligent control theory and strategy of gas drainage pipe network based on graph theory

To address the issues related to the working conditions of the mine gas drainage system and achieve adaptive adjustment of negative pressure during gas drainage, this study proposes a gas drainage pipe network structure model based on graph theory principles. The model is built upon the air-gas mixed flow model of the pipe network. The boundary conditions of the pipe network are determined, and both the pipe network flow model and resistance model are constructed. An assignment iterative adjustment method is used to establish the pipe network solution model, enabling the solution of the gas drainage pipe network. The mathematical model for regulating and controlling the gas drainage pipe network is formulated, considering the objective function, decision variables, and constraint conditions based on the drainage parameters. The control model, along with the flow calculation model of the gas drainage pipe network system, is employed to calculate the optimal gas control scheme. This scheme enables remote intelligent control of the control valve opening on the ground, significantly improving the safety and efficiency of the gas drainage system. The engineering application of Liuzhuang Coal Mine demonstrates the successful realization of the rational distribution of negative pressure and intelligent dynamic control of the drainage pipe network. As a result, the total gas concentration in the drainage pipe network has increased by 12%, yielding favorable outcomes. The findings of this study have significant theoretical and practical implications for the design, development, and improvement of intelligent control systems for mine drainage pipe networks.

Research on urban waterlogging risk prediction based on the coupling of the BP neural network and SWMM model

Abstract Scientific and effective urban waterlogging risk prediction can help improve urban waterlogging disaster prevention capabilities. Combining the numerical simulation model with the data-driven model, the construction of the urban waterlogging risk predictive model can satisfy the prediction accuracy and improve the prediction timeliness. Thus, this paper established an urban waterlogging risk predictive model based on the coupling of the BP neural network and SWMM model, and set five input patterns, finally selected the accumulative precipitation process and precipitation characteristics as input to predict the regional waterlogging risks under different urban rainstorm scenarios. The results show that the overall performance of the pipe drainage system in the study area is lower, and it cannot resist the rainstorm with a higher return period. Moreover, the total waterlogging risk of the southern old city is higher than that of the northern new city in the study area. The calculation speed of the prediction model constructed in this paper is thousands of times higher than that of the numerical model, so the calculation speed is very fast, which meets the requirements of the forecast timeliness.

Effects of Subsurface Pipe Drainage Spacing on Soil Salinity Movement in Jiangsu Coastal Reclamation Area

The agricultural development of reclaimed coastal areas in Jiangsu Province is significantly hindered by high soil salinity and an inadequate irrigation and drainage infrastructure. Optimizing the layout of subsurface drainage systems has been identified as an effective means of reducing soil salinity, with the proper designation of engineering parameters being crucial. This study applied 12 treatments (T1–T12) consisting of four different spacings of subsurface drainage pipes (6 m, 11 m, 15 m, and no subsurface drainage pipes) and three observation wells at varying distances from the drainage outlet (5 m, 25 m, and 45 m). Results showed that all three subsurface pipe spacing treatments significantly reduced soil salinity compared to natural drainage, with a smaller subsurface pipe spacing treatment leading to better salt-reducing effects. The farther the distance from the measuring point to the drain, the higher the salinity. As the burial depth of the outlet decreased and spacing between the subsurface drainage pipes decreased, the salinization rate of the 0–60 cm soil layer was higher, while the salt accumulation in the 60–80 cm soil layer was more severe. Therefore, a subsurface drainage pipe spacing of 6 m and an outlet burial depth of 40 cm are recommended as more suitable choices to effectively control salt concentration in the soil. The research aimed to provide scientific reference data and technical support for the optimized design of subsurface drainage engineering parameters while promoting efficient desalination of saline-alkali areas worldwide.

Simulating the impact of subsurface pipe drainage systems on crop water productivity at a regional scale in the upper Yellow River Basin

AbstractSubsurface pipe drainage (SPD) could provide a suitable environment for crop production in arid and semi‐arid agricultural areas; however, less attention has been given to the design layout of SPD on the regional scale in Hetao Irrigation District (HID). In this study, the appropriate layout of the final subsurface pipe was determined using the distributed SWAP‐WOFOST (Soil–Water–Atmosphere–Plant and WOrld FOod STudies) model in HID. Subsequently, the impact of the proper SPD on crop yield and water productivity (WP) were evaluated. Finally, the crop zoning was adjusted to further enhance crop WP, and the corresponding newly added cultivated land area was preliminarily estimated based on the suggested SPD. The results indicated that after zoning in the suggested SPD, the annual average yields of spring wheat, spring corn and sunflower increased by 19%, 7% and 11%, respectively, and WP improved by 13%, 5% and 10%, respectively, compared to the traditional layout. The newly added cultivated land area was estimated to be approximately 3489 ha through the replacement of traditional end ditches with subsurface pipes in HID. Therefore, the suggested subsurface pipe designs and cropping pattern adjustment improved crop growth and led to an increase in the cultivated land area in HID.

Analysis of Fouling Pattern of Tunnel Drainage Pipe in Karst Areas

Analysis of Fouling Pattern of Tunnel Drainage Pipe in Karst Areas

The influence of drain pipe location and diameter on seepage through an earth dam

Earth dams are built for various reasons these including storage of water, regulation of water flow, prevention of flooding, and the generation of hydroelectric power. The drain pipes within an earth dam, are considered one of the more important control devices used to reduce the effects of problems caused by seepage. As such, the role of drain pipes against seepage problems in an earth dam, has been studied numerically in this investigation. The effects of drain pipe location and their diameters (50, 75, 100, and 150 mm), were examined using different hydraulic heads. The analysis focuses on the characteristics of relative seepage flow, exit gradient, and factor of safety regarding sliding. A range of models of typical earth dams, with and without drain pipes, have been simulated using Geo-Studio software in SEEP/W and SLOPE/W applications, examining more than 200 different cases. By using the data computed from numerical models, new formulas for predicting the seepage parameters and factors of safety were developed in this study by using the multiple non-linear regression (NLR) approaches. The findings show that the presence of a drain pipe reduces seepage flow and the exit gradient, at the same time increasing the factor of safety. Regarding pipe diameter, the rate of seepage and exit gradient decreased while the factor of safety increased as the diameter of the pipe increased. The factor of safety increased by between 11 and 25% when the drain pipe was placed in an optimal position, allowing for a reduction in seepage flow and exit gradient.

Electrolysis characterization of saline wastewater discharged from a subsurface pipe in saline-alkali land

We improved the design of an ion membrane electrolysis device to assess its use for electrolytic desalination and hydrogen production utilizing wastewater discharged from a subsurface drainage pipe in saline-alkali land. The device can reduce the waste of water resources and agricultural non-point source pollution. The electrolysis performance is low due to the low concentration of salts and complex ionic species in the drainage water from subsurface pipes of farmland. A one-factor quantitative experimental study was conducted to assess the influence of the electrolysis parameters on the electrolytic characteristics. Multifactor synergistic optimization of the parameters was performed. The results indicate different degrees of linear correlations between the hydrogen and chlorine gas production rates and the current density (CD) for different process parameters. Different factors have different degrees of influence on the electrolysis characteristics, and factor interactions occur. The optimization model describing the effects of multiple factors on the final current density (FCD), pH value after reaction (ARP), and energy consumption rate (ECR) is reliable and stable. The optimized operating parameters included a brine concentration (BC) of 3.6 mol·L−1, before reaction pH (BRP) value of 9, working voltage (WV) of 12.2 V, and electrode immersion depth (EID) of 22.5 cm. Under these conditions, the FCD is 183.03 mA·cm−2, the ARP is 13.99, and the ECR is 24,586.50 kW·h/kg. The proposed method substantially improves the electrolysis performance. The results provide theoretical and technical support for utilizing saline wastewater discharged from saline-alkaline land.

Stress-corrosion cracking of polypropylene in harsh oxidizing environments

Thermoplastic pipes are widely used in the semiconductor industry, where they are used to drain highly corrosive liquid waste. When exposed to oxidizing environments, thermoplastic pipes can undergo stress-corrosion cracking (SCC), potentially causing them to fail prematurely in the absence of appropriate design and maintenance guidelines. Here, the stress-corrosion cracking behavior of polypropylene, commonly used in waste drainage pipes for dilute sulfuric acid/hydrogen peroxide mixtures (Piranha solutions), is investigated as a function of applied energy release rate. Sub-critical crack growth experiments are performed with compact tension specimens in sulfuric acid/hydrogen peroxide mixtures using a custom constant-force loading system to evaluate the effects of temperature and chemical composition on SCC crack growth. The activation energy for the SCC process is 99.7 ± 15.3 kJ/mol, and the crack growth rate depends sensitively on the concentrations of sulfuric acid and hydrogen peroxide in the mixture. We propose a practical guideline to calculate the service life of polypropylene pipes in Piranha solutions using crack velocity curves and show that accidental exposure to a concentrated Piranha solution can significantly reduce service life.

Subsurface drainage pipe detection using an ensemble learning approach and aerial images

Subsurface drainage pipe detection using an ensemble learning approach and aerial images

Experimental study on slope morphological characteristics and stability analysis of GCHP engineering in the loess plateau

Construction gully slope to terrace (STT) is one of soil and water conservation measure in Gully Consolidation and Highland Protection (GCHP) Project. If the design is unreasonable, not only can’t play its due role, but even more severe soil erosion will occur. In order to quantify the relationship between drainage system of STT and soil erosion, this paper took Fengbao gully head in Dongzhi Plateau as a prototype, and analyzed the hydraulic erosion process of gully head with and without drainage system. Based on the actual precipitation in the area where the prototype is located, three groups of slopes (scenario 1 is an untreated slope, scenario 2 is only STT treatment, and scenario 3 is a STT with a relatively complete drainage system). A series of scouring experiments (flow rates of 0.43, 0.32, 0.86, 1.62, 1.24 and 0.32 m3/h) were carried out on the physical model. The results show that secondary geological disasters such as landslides and diarrhea are more likely to occur on the STT without drainage system than on the untreated slope. Having a relatively perfect drainage system can reduce the sediment concentration to a great extent. The sediment concentration produced by each scouring experiment in scenario 1 is 270.27%, 1018.63%, 479.21%, 250.38%, 556.78% and 151.18% higher than that in scenario 3, respectively. The sediment concentration produced by each scouring experiment in scenario 2 is 486.03%, 1625.21%, 536.96%, 959.29%, 158.94% and 316.67% higher than that in scenario 3, respectively. The sediment concentration fluctuated continuously with time, with multiple peaks and valleys. It is considered that the first few years of construction, if the slope surface after leveling is still exposed, the drainage pipe is suspended to drain and collect water, and the pipeline mouth is directly washed away, which may cause more serious erosion. This study can provide a scientific basis for soil and water conservation and ecological environment construction in the Loess Plateau and the health management of the GCHP Project.