Solid Transfer in Low Flow Sewers, the Distance Travelled So Far Is Not Enough

Sewer blockages are on the increase whilst water closet (WC) flush volumes are on the decrease. Furthermore, Water UK reported figures show that the actual number of properties affected by sewer flooding is on the rise. Sewer blockages can lead to sewer flooding of homes and collapse of sewers which impact negatively on social, economic and environmental factors, and therefore, they are not sustainable. Water conservation is required due to water stress but reduced water use results in less water to waste, which in turn reduces solids’ transfer in sewers. When considering reducing water usage through water conservation, these savings could be cancelled out by an increased population and the situation exacerbated by the impacts of climate change. There are issues in relation to varying design methods, a reliance on engineering judgement in sewer design, uncertainty relating to future water stress, and a lack of cross disciplinary design decision-making. Public health engineering solutions are needed to reduce the number of sewer blockages and the environmental impact of sewer flooding. This paper examines the fundamental research that have been carried out in the area of “solid transfer in sewers” resulting from “less water to waste” since the mid-20th Century. Contrary to existing literature, this paper identifies that, now more than ever, this type of research is needed to deal with the increased need for water conservation. To judge that solid transfer research is complete can be compared to supporting a statement that “water conservation is complete”.

Smart Sewers 1: Sewer Configuration at Rural Houses

The layout of houses and other buildings impacts the way in which foul sewer pipework is positioned internally and externally. Less water to waste through conservation measures reduces the distance that gross solids transfer in sewers and increases the number of sewer blockages. Dwelling houses are often laid out where the solids from faecal flushes are at the head of the sewer line with other flows entering downstream. Discharges from appliances such as washing machines, dishwashers, baths, showers and kitchen/utility sinks are often not utilised in the transfer of the gross solids when they enter downstream of the faecal flushes. At present, no recommendations or specific design guidance exist regarding the design of internal building layouts relating to sewer configuration requirements. Furthermore, to date, no specific research exists which examines pipeline configuration scenarios outside buildings in terms of the link between multiple grey water discharge points and solid transfer in a sewer system. The aim of this study was to investigate sewer layout at houses in terms of maximising greywater flow in relation to solid transfer. This study showed that smart sewers are needed which utilise all the foul water leaving a building as it was found that up to 100% of greywater in some instances is completely missed out in terms of solid transfer. Consequently, optimal sewer design is far from being realised and internal building layouts should be designed with consideration of the faecal flushes and greywater flows.

Characteristics of sewer biofilms in aerobic rural small diameter gravity sewers

Small diameter gravity sewers(SDGS)are extensively used to collect rural sewage as they are low in cost and quick to construct.However,the characteristics of biofilms in rural SDGS are still not clear.In this study,biofilms characteristics of aerobic rural SDGS were investigated using simulations in a lab under different flow conditions and slopes.Results indic ated that the average thickness of aerobic rural SDGS biofilms was in the range of 350-650μm,decreasing at locations with variable flow and high slopes.Protein was the most abundant substance in extracellular polymeric substance of SDGS biofilms.The most abundant bacteria,Proteobacteria,Actinobacteria,and Bacteroidetes,and functional bacteria showed different distributions when analyzed through Illumina HiSeq sequencing of 16 S rRNA.The relative abundances of denitrifying bacteria,nitrite-oxidizing bacteria,and sulfate-reducing bacteria(SRB)were lower during variable flow than during stable flow.High slopes(15‰)decreased SRB presence,which could be used to mitigate H2 S accumulation in aerobic SDGS.Overall,this study describes the characteristics of aerobic rural SDGS biofilms and provides valuable suggestions for the optimal design of SDGS based on these characteristics.

A Composite Transformer-Based Multi-Stage Defect Detection Architecture for Sewer Pipes

Urban sewer pipes are a vital infrastructure in modern cities,and their defects must be detected in time to prevent potential malfunctioning.In recent years,to relieve the manual efforts by human experts,models based on deep learning have been introduced to automatically identify potential defects.However,these models are insufficient in terms of dataset complexity,model versatility and performance.Our work addresses these issues with amulti-stage defect detection architecture using a composite backbone Swin Transformer.Themodel based on this architecture is trained using a more comprehensive dataset containingmore classes of defects.By ablation studies on the modules of combined backbone Swin Transformer,multi-stage detector,test-time data augmentation and model fusion,it is revealed that they all contribute to the improvement of detection accuracy from different aspects.The model incorporating all these modules achieves the mean Average Precision(mAP)of 78.6% at an Intersection over Union(IoU)threshold of 0.5.This represents an improvement of 14.1% over the ResNet50 Faster Region-based Convolutional Neural Network(R-CNN)model and a 6.7% improvement over You Only Look Once version 6(YOLOv6)-large,the highest in the YOLO methods.In addition,for other defect detection models for sewer pipes,although direct comparison with themis infeasible due to the unavailability of their private datasets,our results are obtained from a more comprehensive dataset and have superior generalization capabilities.

Comprehensive health condition assessment on partial sewers in a southern Chinese city based on fuzzy mathematic methods

A self-developed sewer health assessment system using the fuzzy comprehensive evaluation and analytical hierarchy process was applied to give a comprehensive health condition evaluation on part of the local sewers in a southern Chinese city based on the sewer video data collected by a sewer inspection closed circuit television （CCTV） robot. Aside from the overall condition evaluation, the structure, function, and stability status of the sewer were also analyzed using the method. A comprehensive index H was proposed to give the overall health condition of pipes with different defects, and Ht, Hs, and If were used to quantify the defects affecting the tightness, stability, and function of the pipe, respectively. Results show that 48% of the inspected pipes were in good condition （0〈H〈0.25）, and about 33% of the sewer pipes analyzed were categorized to be at severe or urgent condition levels （H 〉 0.5）, although most of the pipes were installed only within five years. Frequent sedimentation affects the function of the sewer, and deformation and joint damage affect the structure of the sewer.

New method for efficient control of hydrogen sulfide and methane in gravity sewers:Combination of NaOH and nitrite

An innovative treatment method by the combination of NaOH and nitrite is proposed for controlling hydrogen sulfide and methane in gravity sewers and overcome the drawbacks of the conventional single chemical treatment.Four reactors simulating gravity sewers were set up to assess the effectiveness of the proposed method.Findings demonstrated hydrogen sulfide and methane reductions of about 96.01%and 91.49%,respectively,by the combined addition of NaOH and nitrite.The consumption of NaNO_(2) decreased by 42.90%,and the consumption rate of NaOH also showed a downward trend.Compared with a single application of NaNO_(2),the C/N ratio of wastewater was increased to about 0.61 mg COD/mg N.The greenhouse effect of intermediate N2O and residual methane was about 48.80 gCO_(2)/m^(3),which is far lower than that of methane without control(260 gCO_(2)/m^(3)).Biofilm was destroyed to prevent it from entering the sewage by the chemical additives,which reduced the biomass and inhibited the recovery of biofilm activity to prolong the control time.The sulfide production rate and sulfate reduction rate were reduced by 92.32%and 85.28%,respectively.Compared with conventional control methods,the cost of this new method was only 3.92×10^(−3)$/m^(3),which is potentially a cost-effective strategy for sulfide and methane control in gravity sewers.

Deep Learning Based Underground Sewer Defect Classification Using a Modified RegNet

The sewer system plays an important role in protecting rainfall and treating urban wastewater.Due to the harsh internal environment and complex structure of the sewer,it is difficult to monitor the sewer system.Researchers are developing different methods,such as the Internet of Things and Artificial Intelligence,to monitor and detect the faults in the sewer system.Deep learning is a promising artificial intelligence technology that can effectively identify and classify different sewer system defects.However,the existing deep learning based solution does not provide high accuracy prediction and the defect class considered for classification is very small,which can affect the robustness of the model in the constraint environment.As a result,this paper proposes a sewer condition monitoring framework based on deep learning,which can effectively detect and evaluate defects in sewer pipelines with high accuracy.We also introduce a large dataset of sewer defects with 20 different defect classes found in the sewer pipeline.This study modified the original RegNet model by modifying the squeeze excitation(SE)block and adding the dropout layer and Leaky Rectified Linear Units(LeakyReLU)activation function in the Block structure of RegNet model.This study explored different deep learning methods such as RegNet,ResNet50,very deep convolutional networks(VGG),and GoogleNet to train on the sewer defect dataset.The experimental results indicate that the proposed system framework based on the modified-RegNet(RegNet+)model achieves the highest accuracy of 99.5 compared with the commonly used deep learning models.The proposed model provides a robust deep learning model that can effectively classify 20 different sewer defects and be utilized in real-world sewer condition monitoring applications.

基于PC机的通信电源远程监控系统的研究

随着通信事业的发展,通信电源系统的可靠性对于保证通信系统的稳定运行越来越重要。为了提高电源系统运行的可靠性,除了对电源本身做出改进,降低故障率以外,对电源系统运行状况进行监控也十分重要。提出了一种新型的现场监控系统结构——基于PC机的通信电源现场监控系统。该系统集采集、控制和管理功能为一体,使用一台PC机来代替传统通信电源集中监控系统中的通信局站PC机后台管理系统和现场单片机监控模块,并以.NET作为开发平台,结合SQL Server数据库技术进行开发。

房产测绘资料管理系统的构建

针对现有房产测绘资料基于文件分散管理的现状,提出了将各种产权测绘资料存入数据库统一管理的基本构想,并构建了一个基于SQL Server的房产测绘资料管理系统。文中对该系统的数据组织、系统基本结构、系统的主要功能和系统开发中一些行之有效的技术解决方案作了详细的讨论。

SQL Server数据库备份与恢复技术的分析与实践

数据库备份与还原是数据库维护的重要环节，是保证数据完整、正确，防止数据丢失的重要手段。在应用系统的维护中，数据库的备份与恢复是数据库管理员（DBA）经常要面对的问题。就SQL SERVER数据库备份与恢复的技术与方法进行探讨，并对一些实例进行分析。

Evaluating Subdivisions for Identifying Extraneous Flow in Separate Sanitary Sewer Systems

Separate sanitary sewer systems are designed to convey sewage waste from municipal areas to a central treatment facility;they are not designed to handle water associated with precipitation events. However, intercept of groundwater (infiltration) and of flows through manholes or unauthorized connections (inflows) introduces rainwater into the sanitary sewer system. Infiltration/Inflow (I/I) increases the costs associated with treatment and can create additional environmental problems. Identifying and quantifying the volume I/I can be complicated and costly. A simple quantitative method was developed to quantify the extent of I/I occurring in sewer sheds. The method uses measured sewer flows, water usage, precipitation values, and land cover data to calculate the volume of extraneous flows. To assess its utility, the method was used to compare two urban sewer sheds, Holiday Knolls and Eagle View. Both sewer sheds showed evidence of I/I in excess of 200 gallons per day per inch-mile of sewer pipe (gpd/in-mile). Holiday Knolls, the older subdivision had an average I/I of 1912 gpd/in-mile, while Eagle View had an average of 1143 gpd/in-mile. The devel- oped method provided simple means to calculate I/I and to identify sewer sheds in need of repair.

网络程序设计中的动态网页制作初探

动态网页中不仅含有HTML标记,而且含有程序代码。它能根据不同的时间、不同的来访者而显示不同的内容。网站安全是一个必须重视的问题。网站存在的安全问题,可根据问题的不同类型有针对性地采取不同的安全技术加以解决。

SQL Server 2005底层数据安全机制的探析及应用

数据库系统安全性是构建数据库系统时值得认真考虑的问题.本文针对微软SQL server2005数据库产品的底层数据安全机制进行了分析,并通过实例详细介绍了在此机制下数据加密和解密的运用方法,提出数据安全性功能的拓展方法.

基于SSIS的运输管理数据中心的建设与研究

随着互联网的迅猛发展，运输管理网络建设进入的一个新的阶段，即数字化交通运输网络，数字化网络以运输管理数据中心为中心，用SQL Server 2005 Integration Service工具，对交通运输管理中的运输、管理等交通运输部门数据进行整合，以实现信息的共享，从而解决交通运输管理“信息孤岛”问题。

Sewage flow optimization algorithm for large-scale urban sewer networks based on network community division

By considering the flow control of urban sewer networks to minimize the electricity consumption of pumping stations, a decomposition-coordination strategy for energy savings based on network community division is developed in this paper. A mathematical model characterizing the steady-state flow of urban sewer networks is first constructed, consisting of a set of algebraic equations with the structure transportation capacities captured as constraints. Since the sewer networks have no apparent natural hierarchical structure in general, it is very difficult to identify the clustered groups. A fast network division approach through calculating the betweenness of each edge is successfully applied to identify the groups and a sewer network with arbitrary configuration could be then decomposed into subnetworks. By integrating the coupling constraints of the subnetworks, the original problem is separated into N optimization subproblems in accordance with the network decomposition. Each subproblem is solved locally and the solutions to the subproblems are coordinated to form an appropriate global solution. Finally, an application to a specified large-scale sewer network is also investigated to demonstrate the validity of the proposed algorithm.

Prediction of Sewer Pipe Main Condition Using the Linear Regression Approach

This research presents the condition prediction of sewer pipes using a linear regression approach. The analysis is based on data obtained via Closed Circuit Television (CCTV) inspection over a sewer system. Information such as pipe material and pipe age is collected. The regression approach is developed to evaluate factors which are important and predict the condition using available information. The analysis reveals that the method can be successfully used to predict pipe condition. The specific model obtained can be used to assess the pipes for the given sewer system. For other sewer systems, the method can be directly applied to predict the condition. The results from this research are able to assist municipalities to forecast the condition of sewer pipe mains in an effort to schedule inspection, allocate budget and make decisions.

InTouch9.0在电厂输煤程控系统中的应用

根据电厂输煤基本原理,提出了应用InTouch9.0软件设计某电厂输煤程控系统的方法,介绍了系统的设计,生产过程中的数据显示、记录、处理和报警,以及InTouch9.0通信原理和配置。实现了对系统控制、维护与管理的集成。

Experiment study on solidification effect of sewer sludge

Materials such as cement and composite active admixture were mixed in definite ratio to consolidate sewer sludge, which had been dried and smashed. Two kinds of solidified bodies were designed. A represented the solidified body which had not used any composite active admixture, and B represented the one which used composite active admixture as one of its compositions. The results show that the compressive strength （28 d） of these solidified bodies can reach 30 MPa under the standard maintain condition which could be used as subgrade material. The concentration of heavy metals in solidified body was far less than identification standard for hazardous wastes of China. Heavy metals were stabilized and solidified effectively. The organic matter in these solidified bodies of 56 d was 80 percent less than that in raw sludge. A large quantity of bacteria could also be killed because of the basic condition in solidified body. Scanning electron microscope （SEM） test explained the reason that solidified body B showed better properties in all tests.

Global optimal control for regional sewer systems

In order to control combined system overflow (CSO) pollution of regional sewer systems in Shanghai,a global optimal control (GOC) is presented in this study.The GOC is based on the analysis of current situation and can maximize the utilization of the free storage of each sub systems and decrease the frequencies and durations of CSOs and flooding.A representative regional sewer system,which is located in the northwest of Shanghai and composed of sub systems of Zhenguang,Zhenru and Tongchuan,was taken as an example to demonstrate the efficiency of GOC with hydraulic model simulation test in the two representative scenarios (Scenario Ⅰ and Ⅱ).The results indicated that a great improvement in CSO emission is obtained by using the GOC in the two scenarios,and the CSO volume of three sub systems,Zhenru,Tongchuan and Zhenguang decreases to about 37.0%,38.3% and 35.7% in Scenario Ⅰ and 47.5%,51.8% and 63.5% in Scenario Ⅱ respectively.

Multi-Level Approach of the Ecotoxicological Impact of a Combined Sewer Overflow on a Peri-Urban Stream

In periurban zones, urban wet weather discharges have been recognized as the most significant vector of pollution in aquatic environments. The discharge of this water without treatment into the aquatic environment could present an ecotoxicological risk for biocenosis. The aim of the INVASION project is to assess the potential ecotoxicological impact of a combined sewer overflow (CSO) on a peri-urban stream. A comparative study between upstream and downstream areas of the CSO allowed observing significant effects of this overflow on the river. We studied three layers of stream: surface water, benthic layer and hyporheic layer. To characterize the potential ecotoxicological risk of water and sediments, we used a battery of 4 bioassays: Daphnia magna, Vibrio fischeri, Brachionus calyciflorus and Heterocypris incongruens. In parallel, we measured the physico-chemical parameters: ammonium (NH4+), chromium (Cr), copper (Cu) and lead (Pb). An ecological risk is greatest for the hyporheic zone in downstream river, particularly for the solid phase. These results corroborated with the physico-chemical data obtained.