Digital Twins for Wastewater Treatment:A Technical Review

The digital twins concept enhances modeling and simulation through the integration of real-time data and feedback.This review elucidates the foundational elements of digital twins,covering their concept,entities,domains,and key technologies.More specifically,we investigate the transformative potential of digital twins for the wastewater treatment engineering sector.Our discussion highlights the application of digital twins to wastewater treatment plants(WWTPs)and sewage networks,hardware(i.e.,facilities and pipes,sensors for water quality and activated sludge,hydrodynamics,and power consumption),and software(i.e.,knowledge-based and data-driven models,mechanistic models,hybrid twins,control methods,and the Internet of Things).Furthermore,two cases are provided,followed by an assessment of current challenges in and perspectives on the application of digital twins in WWTPs.This review serves as an essential primer for wastewater engineers navigating the digital paradigm shift.

A Cradle-to-Cradle Novel Approach for Wastewater Management in Sustainable Urban Communities

Water, a valuable resource to human lives, is being abused and driven to scarcity. This scarcity is leading some countries and areas to face difficulty in accessing drinking water. As the UN recently stated “by 2050 water shortages and harder access will be reached by around 2/3rd of the world total population” [1], thus, there is a high need to treat and reuse wastewater for domestic purposes, which will lead to less reliance on fresh water as an initial water source. Greywater—defined as the water produced in domestic houses including sinks and bathroom showers, and excluding any blackwater mix which is collected from toilets—is a type of wastewater. Greywater accounts for up to 75% of the daily water produced [2] while it has fewer contaminants when compared to blackwater. This makes greywater a focal point for treatment, and reusing to conserve fresh water and approach net zero water concept. Even though the definition of greywater is the same globally, its criteria can differ from one country to another, from one building to another, or even from the same person’s usage along the day. Accordingly, several treatment methods evolved over years aiming at treating the produced greywater for reuse mainly in irrigation and toilet flushing. The objective of this paper is to demonstrate a novel net zero wastewater approach applying cradle-to-cradle concept for urban communities;while also proposing a sustainable greywater treatment technique that is environmentally friendly, cost-effective and socially acceptable.

Water quality of reclaimed water from treated urban wastewater in Chaobai River Basin,North China

The utilization of reclaimed water could be an efficient tool to alleviate water scarcity,especially for dry river augmentation.However,it is crucial to monitor water quality to ensure safety to human health and to avoid negative effects on the environment.Reclaimed water samples were collected bimonthly from May to November in 2010 in Chaobai River,and the physiochemical parameters were determined.The main results are as follows:The parameters exceeding the threshold value of the water guidelines are mainly nutrition related to nitrogen and phosphorus,which are known to increase the risk of eutrophication in surface waters.Additionally,nitrite and nitrate can be detrimental to human health.The majority of the parameters have a peaking concentration in May,whereas others either show significant temporal variation over the entire period or remain relatively constant in all four months.Correlation analysis shows that some parameters(pH,T and B) have no significant correlation with others,whereas significant positive correlation was found for Sr with EC and TDS,for CI with TDS,for Si02 with TP and for NO3-N with TN and a significant negative correlation between SO4 and Ba.According to principal component analysis,60.108%of the total data is represented by dominant solutes,and the second principal component with a percentage of 31.876 comprises parameters related to nitrogen.Subsequent cluster analysis of parameters identified four groups,which represent different compositions,and samples in May differ from others.

Heavy Metal Contaminated Food Crops Irrigated with Wastewater in Peri Urban Areas, Zambia

Studies on peri urban farming in Zambia have not adequately tackled the issues pertaining to heavy metal contaminated wastewater irrigation farming. The study investigated heavy metal contamination of water, soils and crops at two peri urban areas in Zambia. Two study sites were New Farm Extension in Mufulira Town in the Copperbelt Province and Chilumba Gardens in Kafue Town in Lusaka Province. The heavy metals investigated were lead, copper, cobalt, nickel and chromium. These heavy metals were found to be higher than acceptable limits in wastewater used to irrigate crops and there are potential human health risks associated with consumption of heavy metal contaminated food crops which have implications on the livelihoods of people. Samples of water, soil and crops were collected and analysed for lead (Pb), copper (Cu), chromium (Cr), cobalt (Co) and nickel (Ni) using the Atomic Absorption Spectrometer (AAS). The data on heavy metals was analysed using mean, standard error and T-test. The results indicated that the levels of heavy metals in wastewater, soil and food crops were above acceptable limits at two study sites. It can be concluded that there was heavy metal contamination of wastewater, soil and food crops at the two peri-urban areas in Zambia. The study highlighted the actual levels of heavy metal contaminant uptake in food crops consumed by the peri urban population. The information from this study can be used by the relevant authorities to develop appropriate measures for monitoring and control of heavy metal contamination in wastewater irrigation farming systems in peri urban areas inZambia.

Management of Urban Wastewater in the City of Maradi (Niger): The Case of Domestic Wastewater

Uncontrolled urbanization of African cities and the lack of municipal waste management services in these cities make landscapes become places of multiple and varied interactions between health and environment. In this sense, under strong urban growth in a context of sub-equipment sanitation, the city of Maradi doesn’t escape to this situation which results in the spread of pollution (release of unpleasant odors, and proliferation of mosquitoes) and many diseases posing multiple health problems. Our study focuses only on liquid waste especially domestic wastewater. To study the different domestic wastewater management options in the town of Maradi, a survey was conducted among 340 households in 17 districts. We note in most cases a crucial of waste management infrastructure (drainage and wastewater treatment) in the city. Thus, only the individual sanitation facilities are used. In the town of Maradi, in addition to the storm drains, there are, in old districts, ditches that discharge wastewater and unfortunately end up in rivers without treatment. Total domestic wastewater production is estimated at 86761.28 m3 per day. This water is mostly from laundry activities, bathing, dishes, and is discharged in large part through the streets, by more than 60% of households. Also, pit emptying is performed at 39.11% by the vehicle Peugeot tank. The quality of service rendered by an actor is very important to encourage households to join. Existing autonomous sanitation facilities are poorly designed and poorly maintained. Fecal sludge is dumped in a hole near saturated latrines;this work is mainly done by manual scavengers or dumped in fields or on nearby vacant land concessions.

Study of Heavy Metal Uptake by the Crops Grown by Using Urban Wastewater of Mysore City, India

In the 21st century the fresh water scarcity increased very rapidly due to the urbanization and industrialization process. In these conditions the urban wastewater plays an important role in the water usage criteria. In this aspect, in all the major cities, wastewater treatment plants have been constructed to treat the urban wastewater in view of decreasing the water scarcity. The presence of nutrients in the wastewater is considered as beneficial to agricultural practices. The contaminants present in the wastewater pose health risks directly to agricultural workers and indirectly to the consumers as the long term application of the wastewater may result in the accumulation of toxic elements in soil and in plants. In this way the heavy metals will circulate among the food chain and food web to cause adverse effects on human health as well as on soil health. In the present study an attempt has been made to study the characteristics of urban wastewater at wastewater treatment plant of Mysore city. And also heavy metal behavior was studied with the analysis of heavy metals in wastewater, Biosolid and receiving soil along with the plants which indicates the uptake of heavy metals.

Urban Wastewater Treatment by Adsorption of Organic Matters on Modified Bentonite by(Iron-Aluminum)

In this research, the natural bentonite clay (from Maghnia, western Algeria) was purified (Na+- montmorillonite, CEC = 91 meq/100 g), noted (puri.bent) and modified with mixed hydroxy-Fe-Al (FeAl-PILC). The purified bentonite clay and FeAl-PILC were heated at 383 K for 2 hr and characte-rized by the chemical analyses data, XRD, and N2 adsorption to 77 K techniques. Puri.bent and FeAl-PILC were applied to fix the organic matter (OM) present in urban wastewater from the city of Sidi Bel-Abbes (western Algeria). The adsorption of organic matter was followed by spectro-photometry at 470 nm, and the adsorption data were a good fit with Freundlich isotherm for pu-ri.bent but for FeA-lPILC, were well fit by Elovitch isotherm model. The maximum adsorption ca-pacity (qm) was 571.6 mg/g for puri.bent and 1120.69 mg/g for FeAl-PLC. The degree of OM removal was 67% for puri.bent and 97% for FeAl-PILC. FeAl-PILC can be considered as a promising adsorbent for the removal of OM from wastewater.

Wastewater Management in Third World Cities: Case Study of Cotonou, Benin

Poor wastewater management coupled with lack of sanitation facilities has aggravated the sanitation challenges in developing countries.?This study was aimed at providing information on the current state of sanitation in Cotonou City through surveys. The most common sanitation facilities in the city were septic tanks, latrines and soakaway pits. Mechanical desulging was mainly used (94%) for desludging latrines and septic tanks with a frequency of less than once a year for 73% of the houses;manual desludging was most common for soakaway pits. 84% of sullage generated is disposed without treatment. The only existing stabilization pond plant, managed by a private company SIBEAU, is overloaded;the effluent is poor (up to 2250mg/l BOD5) and does not meet any quality standards. 96% of survey respondents recognise that the sanitation situation in the city is not good;it has to be improved by providing an appropriate and sustainable sanitation management system.

Low-carbon city communication:Integrated strategies for urban and rural municipalities in Thailand

As an important sustainable development goal,the creation of low-carbon cities(LCCs)has become crucial to creating livable cities and environmental sustainability.Thus,we aimed to understand the factors that support the transition of traditional cities to LCCs,by analyzing and synthesizing how to promote practical LCC across 15 pilot municipalities in four regions of Thailand,covering four strategies:City of Trees,City of Waste Minimization,City of Energy Efficiency,and City of Sustainable Consumption.Literature research,in-depth interviews,and observations were employed for data collection,while the 5​W(who,says what,in which channel,to whom,and with what effect)and SMCR(sender,message,channel,and receiver)models were used to create a communication analysis framework.Results revealed that the effective activities of municipalities should increase tree planting and implement more serious regulations for the conservation of existing trees.Making compost and establishing waste recycling banks are recommended for rural municipalities,while optimization of garbage and wastewater management systems and facilities should be highlighted in urban municipalities.Moreover,recycling,low-carbon agriculture,second-hand shops/markets,green markets,and homegrown vegetables should be encouraged for sustainable consumption.Working with local municipalities,credible leaders and representatives were the key senders.Additionally,message design should compare the pros and cons of behaviors,connect with local health and tourism,and promote dialogue in easy-to-understand and thought-provoking language.Receivers that drive LCC should have an excellent understanding of LCC practice and its benefits,be public-minded,and have a desire to live in a good environment.

Study on Low-carbon City Planning Strategies Based on Urban Greenhouse Gas Inventory

From the perspective of urban greenhouse gas inventory, this paper analyzed the composition and tendency of urban greenhouse gas inventory of Guangzhou, and compared greenhouse gas inventory of representative international cities. Taking Guangzhou Haizhu Eco-city for example, this paper from the perspective of urban-rural planning put forward the low-carbon development paths and strategies such as increasing carbon sink, industrial transformation, spatial restructuring, traffic organization, green civil engineering and resource utilization, and green building for the main carbon-emitting fields such as industry, energy supply, transport, building and waste disposal.

Examination of the Level of Heavy Metals in Wastewater of Bandar Abbas Wastewater Treatment Plant

One of the main environmental pollutants is heavy metals. Due to extensive usage in industry, these metals enter biological cycle rapidly and contaminated water and soil resources rapidly. In this work, lead, copper, zinc and chromium of Bandar Abbas wastewater are examined. For this research, nine stations were set for measurement in urban level in Bandar Abbas and sampling of aforesaid metals was performed in fall and winter 2006 in these stations. After extraction and preparation operations using APDC-MIBK, samples were measured using flame atomic absorption system. According to results, concentrate of studied metals was lower than allowable standard value set by Iran environmental protection organization for agricultural purposes and sewage to ground level waters. In addition, efficiency of Bandar Abbas wastewater treatment plant to remove these metals is 40% - 70% from which highest removal is for zinc as much as 71.1% and lowest level is for copper as much as 40.5%. However, copper level was higher than allowable level for agricultural purposes in spring and summer (0.21 mg/L and 0.23 mg/L, respectively) and lower in fall and winter (0.103 mg/L and 0.098 mg/L, respectively). Furthermore, changes in concentration of metals in these stations in various seasons were measured and analyzed using one-way variance analysis and simultaneous effects of time and place on measured variables were analyzed using two-way variance analysis.

“A/RPIR+磁混凝沉淀”组合工艺处理城镇废水的稳定运行效能分析

“A/RPIR+磁混凝沉淀”组合工艺具有运行能耗低,投资节省,占地少,运行稳定,出水水质好等优势,已在河道黑臭水体治理及市政污水处理领域得到广泛应用。本文对某市政污水处理厂(A/RPIR+磁混凝沉淀工艺、设计规模10×10^(4)m^(3)/d)的稳定运行效能进行分析评估。结果表明,水厂出水水质全部稳定达标,年平均吨水电耗为0.196kWh,产出泥饼含水率相对稳定,平均为79.5%,日泥饼产量为74.1 t,污泥产率为1.14×10^(4)TDS/m^(3)。污水厂整体运行效能良好。

城市污水处理技术的进展与未来挑战:以持续减排为目标

本文系统回顾了城市污水的主要污染物,总结了现有的污水处理技术,并重点探讨了以持续减排为目标的新型污水处理技术,如微生物技术、膜分离技术和纳米技术等。最后,本文还分析了未来污水处理技术发展中要面临的挑战,以及未来的研究方向,为城市污水处理技术的发展提供参考。

进一步改善城市网-厂-水体污水系统升级改造和运行效率的四点看法

2022年,《深入打好城市黑臭水体治理攻坚战实施方案》发布,要求努力解决河流雨后黑臭和雨季河流断面水质下降问题,力争到2025年,进水BOD浓度高于100毫克/升的城市生活污水处理厂规模占比达90%以上,城市生活污水集中收集率达到70%以上。水行业正面临着防止雨后河流返黑和改善雨季河流水质等新任务。因此,结合近年来成绩、实践和欧美的经验教训,提出和讨论了与进一步改善网-厂-水体城市污水系统升级改造及运行效率相关的四个问题:分流制管网有没有外(雨)水入侵和溢流、污水处理厂的进水浓度应多高、为什么部分污水处理厂需局部扩容、为什么污水管道中流速低于自净流速,并在此基础上,对相关工作提出了建议。

Greywater reuse as a key enabler for improving urban wastewater management

Sustainable water management is essential to guaranteeing access to safe water and addressing the challenges posed by climate change,urbanization,and population growth.In a typical household,greywater,which includes everything but toilet waste,constitutes 50e80%of daily wastewater generation and is characterized by low organic strength and high volume.This can be an issue for large urban wastewater treatment plants designed for high-strength operations.Segregation of greywater at the source for decentralized wastewater treatment is therefore necessary for its proper management using separate treatment strategies.Greywater reuse may thus lead to increased resilience and adaptability of local water systems,reduction in transport costs,and achievement of fit-for-purpose reuse.After covering greywater characteristics,we present an overview of existing and upcoming technologies for greywater treatment.Biological treatment technologies,such as nature-based technologies,biofilm technologies,and membrane bioreactors(MBR),conjugate with physicochemical treatment methods,such as membrane filtration,sorption and ion exchange technologies,and ultraviolet(UV)disinfection,may be able to produce treated water within the allowable parameters for reuse.We also provide a novel way to tackle challenges like the demographic variance of greywater quality,lack of a legal framework for greywater management,monitoring and control systems,and the consumer perspective on greywater reuse.Finally,benefits,such as the potential water and energy savings and sustainable future of greywater reuse in an urban context,are discussed.

双模式MSBR工艺在城镇污水厂雨季工况中的中试试验

我国城镇污水处理厂在雨季往往面临短时间激增的水力冲击负荷,因污水厂二级处理系统通常按旱季流量设计,无法应对超量的雨季合流污水,导致厂前溢流或厂内超越,严重污染了受纳水体。研究采用含多点进水功能的双模式改良型序批间歇反应器(MSBR)在浙江某污水处理厂模拟雨季超量合流污水的生化处理,通过中试试验证明了该工艺可在合流污水达到2~4倍旱季设计流量的条件下,确保COD_(Cr)、氨氮、总氮(TN)等主要出水指标稳定达到并优于《城镇污水处理厂污染物排放标准》(GB 18918—2002)中一级A标准,其中出水氨氮平均质量浓度小于1.0 mg/L,TN平均质量浓度小于10 mg/L。其处理效果显著优于物理-化学强化一级处理工艺,为大幅提升污水处理厂的雨季峰值流量处理能力,有效削减雨季受纳水体的冲击性污染,消除城镇黑臭水体提供了新的解决方案。

城市生活废水处理及环境保护措施研究

城市生活废水是指城市居民未经处理即排放的生产生活用水,对河流、湖泊等造成严重污染。城市生活废水中的污染物种类繁多,不仅对生态环境造成严重危害,还对水生态系统的正常运转和居民的身体健康造成极大影响。基于此,本文主要介绍了城市生活废水的几种处理方法,包括物理处理、化学处理、生物处理和生态处理等方法,并提出了加强环境保护的措施。

膜生物反应器(MBR)技术在城市污水处理中的优化探讨

本文主要以某实际项目为例,对膜生物反应器技术在现代城市污水处理中的优化进行分析。包括本次所研究的某城市污水处理项目概况,以及城市污水处理中的膜生物反应器技术优化分析。经分析可知,在对膜生物反应器技术进行优化时,研究者与技术人员首先需要结合实际情况来确定基本的优化思路,然后再以此为依据,科学制定优化方案。通过这样的方式,才可以获得良好的优化效果,满足现代城市污水处理的实际需求。

城市污水处理厂中邻苯二甲酸酯的分布规律及去除途径

城市污水处理厂中邻苯二甲酸酯又称酞酸酯,缩写PAEs,是一类常见的有机污染物,主要来源于塑料制品、化妆品、医疗器械等生活用品的使用和排放。这些物质具有潜在的环境和健康风险,因此需要在污水处理过程中有效去除。本文探讨解决这一有机污染物在城市污水处理中的问题,从而减少其对环境和健康的潜在威胁。

市域铁路隧道道床内置式区间废水泵房排水设计

以上海市域线机场联络线为例,探讨解决道床内置式区间废水泵房排水设计的关键技术。市域铁路具有区间长、埋深大的特点,通过分析道床内置式区间废水泵房的设计思路、总结既有案例,结合项目具体情况,针对设计重难点提出解决方案,可供类似工程借鉴。