In the context of climate change and increasing water scarcity, adopting water demand-side management (DSM) policies has become necessary. This study advocates for utilising agent-based modelling (ABM) as a robust simulation tool to assess the impact of nonprice (nudges) and price (changes in increasing block tariff) measures on urban water use. Overcoming challenges posed by insufficient high-quality data, the research integrates four sociocognitive profiles and diverse household income levels to reflect the variability in DSM policy effectiveness based on socioeconomic characteristics. Through 125 simulated scenarios combining various increasing block tariffs with nonpricing measures, the study reveals an average monthly demand reduction ranging from 8.1% to 15.6%. Significantly, nonprice measures prove more effective in curbing water use than pricing measures, attributed to the prioritisation of environmental concerns in conservation efforts. Higher-income households exhibit less-pronounced reductions in water consumption. Emphasising the reliability of ABM for ex ante evaluations of DSM policies, this research underscores the importance of a balanced approach, incorporating both nonprice and price-based measures, to effectively address water scarcity challenges.

The water sector could play a major role towards a Net Zero greenhouse gas (GHG) future if Scope 3 emissions were embraced and operationalised. Significant opportunities and challenges exist in tackling Scope 3 emissions including those associated with customer hot water use. Present GHG emission reduction practices predominantly focus on Scope 1 "within utility" and Scope 2 "purchased energy" emissions. In the urban water cycle, Scope 3 "indirect" emissions dominate, and water use is only one example of Scope 3 emissions. Over 90% of all water cycle GHG emissions can be attributed to water use in residential, industrial and commercial premises, collectively some 7% of global GHG emissions. One possibility is for water utilities to actively support efficient hot water use such as new ultra-low flow shower heads. Scope 3 opportunities also offer a range of cost-effective emissions-reduction opportunities, particularly when the wider perspective of "community value" is considered and not just a "business financial perspective". Hot water efficiency is additionally essential to Net Zero carbon futures, even with decarbonised grids, because most major Net Zero roadmaps require energy efficiency gains. Scientific and management advance needed includes: accounting methodologies, clear roles, collaboration, new business models, and clear definitions. The water sector has the opportunity to play a significant role in achieving Net Zero cities. The decision how much is yet to be made.

The key message is the importance of a systemic approach to handling water and energy together, both in design and in operation. The paper demonstrates how renewable energy, solar photovoltaic (PV) and solar thermal, in combination with a small nutrient removal plant provides a reliable solution for small-scale decentralized water recovery operations. The system is automated and can operate outside the power grid and is designed to be a fully circular system in terms of both energy and water. The system has been installed on an island in the archipelago outside Stockholm, Sweden, to replace an old-fashioned septic tank. The effluent must satisfy rather strict effluent quality criteria for the Baltic Sea. The paper describes design considerations, instrumentation aspects, automation features, and operation experiences.

The 1st edition of the textbook Biological Wastewater Treatment: Principles, Modelling and Design was published in 2008 and it went on to become IWA Publishing's bestseller to date. In 2020, the 2nd updated and extended edition of the textbook was published because, since 2008, the knowledge and understanding of wastewater treatment had advanced extensively and moved further away from empirically-based approaches to a fundamental first-principles approach based on chemistry, microbiology, physical and bioprocess engineering, mathematics and modelling. The updated edition has already been available for more than two years and the feedback from readers has been overwhelming - the textbook won the IWA Publishing Best Scientific Book Prize in 2022. This inspired the authors to embark on a new challenge - to prepare this complementary book Biological Wastewater Treatment: Examples and Exercises. This new book is an extension of the 2nd edition textbook; each chapter corresponds to a chapter in the textbook and is structured similarly around five sections, namely, Introduction, Learning objectives, Examples, and Exercises, with solutions provided in an annex. The overall objective of the book is to deepen, expand and test the knowledge of the reader through a set of worked out examples, followed up by exercises and questions with provided answers. Where applicable, the book is supplemented with MS Office Excel files. The book is open access and can be downloaded (together with supplements) at the publisher's website. The target readership of the book remains young water professionals, who will still be active in the field of protecting our precious water resources long after the aging professors who are leading some of these advances have retired. The authors are aware that cleaning dirty water has become more complex but also that it is even more urgent now than before, and offer this new book to help young water professionals engage with the scientific and bioprocess engineering principles of wastewater treatment science and technology with deeper insight, advanced knowledge and greater confidence built on stronger competence.

Digitalisation has developed over half a century and is one of the global trends defining society of today and future. Digitalisation is envisioned to help water utilities to become: i) community orientated and digitally integrated with customers and society; ii) digitally transformed end-to-end throughout the value-chain and interconnected between business units; iii) predictive & proactive, utilizing models and applications for control and decision support; iv) visually communicative with customers and society, creating customers aware of the value of water; and financially sustainable by optimal operation (OPEX), and sustainable investments (CAPEX). Digitalisation is a process for business development, where digital solutions are used for automation and innovation. Utilizing the potential of the technological innovation requires a parallel organisational transformation. Any implementation of systems or applications must be motivated in actual needs for the organisation and service delivery. Prior to any digitalisation, identifying issues and areas of improvement is essential. Starting the digital journey, motivating employees, improving the digital culture and creating acceptance of new processes are needed on all levels. Most digital applications require collection, storage, sharing and integrated analysis of large amounts of data. This includes both soft and hard digital infrastructure.

Improving Utilities with Systems Thinking: People, Process, and Technology explores management of water sector utilities from a systems thinking point of view, starting with the complete system and then defining the components, considering the interactions between them, measuring key variables of value creation and impact, making adjustments, and learning. The overall goal is to establish a knowledge-based roadmap for improvement, including practical methodologies based on science and grounded in the real needs of water sector utilities as stewards of a fundamental component of life: water. ISBN: 9781789063134 (Paperback) ISBN: 9781789063141 (eBook)

During the last two decades, the interrelationship between water and energy has become recognized. Likewise, the couplings to food and agriculture are getting increasingly obvious and alarming. In the last year, a record number of extreme weather events have been reported from most parts of the world. This is a visible demonstration how consequences of climate change must be understood and alleviated. The impacts of economics, lifestyle, and alarming inequalities are becoming increasingly recognisable. If the wealthy part of the world is not willing not make radical changes it does not matter what the less wealthy half of the global population will do to meet the climate and resource crisis. The purpose of the book is to demonstrate and describe how climate change, water, energy, food, and lifestyle are closely depending on each other. It is not sufficient to handle one discipline isolated from the others. This is the traditional “component view”. The book defines and describes a systems view. The communications and relationships between the “components” have to be described and recognized. Consequently, the development of one discipline must be approached from a systems perspective. At the same time, the success of the systems perspective depends on the degree of knowledge of the individual parts or disciplines. The catchphrase of systems thinking has been caught in the phrase, “The whole is more than the sum of its parts”. The idea is not new: the origin of this phrase is to be found already in Aristotle's Metaphysics more than 2300 years ago. The text may serve as an academic text (in engineering, economics, and environmental science) to introduce senior undergraduate and graduate students into systems thinking. Too often education encourages a “silo” thinking. Current global challenges can't be solved in isolation; they depend on each other. For example, water professionals should have a basic understanding of energy issues. Energy professionals ought to understand the dependency on water. Economic students should learn more how economy depends on natural resources like energy and water. Economics must include the environmental impact and ecological ceiling of economic activities. ISBN: 9781789062892 (print) ISBN: 9781789062908 (eBook) ISBN: 9781789062915 (ePUB)

This study highlights the need to increase our understanding of the interplay between sensor drift and the performance of the automatic control system. The impact from biased sensors on the automatic control systems is rarely considered when different control strategies are assessed in water resource recovery facilities. Still, the harsh measurement environment with negative effects on sensor data quality is widely acknowledged. Simulations were used to show how sensor bias in an ammonium cascade feedback controller impacts aeration energy efficiency and total nitrogen removal in an activated sludge process. Response surface methodology was used to reduce the required number of simulations, and to consider the combined effect of two simultaneously biased sensors. The effects from flow variations, and negatively biased ammonium (-1 mg/L) and suspended solids sensors (-500 mg/L) reduced the nitrification aeration energy efficiency by between 7 and 25%. Less impact was seen on total nitrogen removal. There were no added non-linear effects from the two simultaneously biased sensors, apart from an interaction between a biased ammonium sensor and dissolved oxygen sensor located in the last aerated zone. Negative effects from sensor bias can partly be limited if the expected bias direction is considered when the controller setpoint-limits are defined.

Automation is a collection of a whole set of theories and methods to make a system work automatically as intended, in our case the urban water supply system. A critical feature of automation is the feedback principle: a sensor is measuring a certain variable, e.g. a concentration; a computer tests that the measurement is valid; a computer algorithm calculates and decides what should be corrected; a pump or valve or some other device transforms the decision to action. All of this is untouched by human hand. The ‘intention’, or the goal, must be provided to the controller. The key component of automation is the system that can represent any component or process in the water supply system and even the complete system. Automation technology always must be combined with a true understanding of people at all levels. Otherwise, there is a high risk for misunderstandings and failures. Three categories of problems are highlighted, where automation can contribute: uncertainty, feedback, and complexity. A key challenge is the handling of disturbances. Integrated management of the whole urban water cycle will be required in future urban areas to acquire sustainable operations. Automation is a crucial condition to make integration possible in complex systems.

Urban water systems and, in particular, wastewater treatment facilities are among the major energy consumers at municipal level worldwide. Estimates indicate that on average these facilities alone may require about 1% to 3% of the total electric energy output of a country, representing a significant fraction of municipal energy bills. Specific power consumption of state-of-the-art facilities should range between 20 and 45 kWh per population-equivalent served, per year, even though older plants may have even higher demands. This figure does not include wastewater conveyance (pumping) and residues post-processing. On the other hand, wastewater and its byproducts contain energy in different forms: chemical, thermal and potential. Until very recently, the only form of energy recovery from most facilities consisted of anaerobic post-digestion of process residuals (waste sludge), by which chemical energy methane is obtained as biogas, in amounts generally sufficient to cover about half of plant requirements. Implementation of new technologies may allow more efficient strategies of energy savings and recovery from sewage treatment. Besides wastewater valorization by exploitation of its chemical and thermal energy contents, closure of the wastewater cycle by recovery of the energy content of process residuals could allow significant additional energy recovery and increased greenhouse emissions abatement.

This paper presents a modelling study aimed at minimizing the environmental foot print of a membrane bioreactor (MBR) for wastewater treatment. Specifically, an integrated model for MBR was employed in view of the management optimization of an MBR biological nutrient removal (BNR) pilot plant in terms of operational costs and direct greenhouse gases emissions. The influence of the operational parameters (OPs) on performance indicators (PIs) was investigated by adopting the Extended-FAST sensitivity analysis method. Further, a multi-objective analysis was performed by applying the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The results show-up that the sludge retention time is the OP mostly affecting all the investigated PIs. By applying the set of optimal OPs, there was a reduction of 48% and 10% of the operational costs and direct emissions, respectively.

The coupled relationships among water, energy, and emission, i.e., water-energy-emission nexus (WEEN), are found to be spatial-temporally characterized. This research is aimed at evaluating the spatial-temporal characteristics of the WEEN of the selected 227 coal-fired power plants in China from 2012 to 2014 by employing the entropy weighting method. Firstly, the WEEN performances (the sub-indicators, i.e., the emissions, water for cooling, water for pollutant removal, energy for electricity generation, and energy for pollutant removal) of the plants are computed. Then, each sub-indicator of the WEEN performances is compared at plant level. Finally, the entropy weighting factor is introduced to evaluate the overall performances of WEEN (defined as the WEEN indicator). The results show that NOx and SO2 removal sub-indicators were with the highest entropy weights. Overall, the WEEN indicator improves significantly from 0.21 (2012) to 0.37 (2014), which means the increases of pollutant removal were more significant than the changes in water and energy inputs. The power plants located in Northern China and Central China grids show more significant improvement. This is mainly contributed by the improvement of the three emission sub-indicators and the larger amount of removed pollutants. By evaluating the improvement of WEEN indicators, the overall performances of WEEN with the simultaneous consideration of water, energy and emission are quantitatively addressed, which reflect the technology improvement and the strict policies and regulations behind it. This research provides a quantifiable and integrated way to evaluate and compare the various aspects of WEEN at the plant level.

Relocating Beijing's manufacturing industry, a key measure in the strategy for decentralizing Beijing's non-capital functions, may inadvertently increase environmental pressures in the receiving cities. This study develops a quantitative method to comprehensively identify the environmental effects caused by regional industrial relocations. First, a set of relocated industries is selected by considering the relevant policy motivations and sector-specific economic and environmental performance. Second, a discrete choice model is developed to simulate the relocating process, taking economic geographic factors as well as local environmental quality and regulation into account. Third, the Monte Carlo method is used to quantify the potential effects by considering the sectoral efficiencies of resource use and pollutant emissions. Three scenarios are developed for different priorities of economic growth and environmental regulation. The results show that the decentralization strategy is likely to reduce Beijing's industrial output value by between 68 and 176 billion RMB yuan, or 3.9%–10.1% of its annual total. Meanwhile, the decrease in Beijing's industrial water and energy consumption could range from 2.7% to 7.8% and from 6.4% to 8.1%, respectively, while the decrease in industrial emissions from various pollutants could range from 6.7% to 36%. The industrial output from the receiving cities in the Beijing–Tianjin–Hebei (BTH) region could increase in the range of 0.3%–17% in the scenarios, larger than their change rate of water and energy consumption (0.1%–3.5%) and pollutant emissions (0.1%–7.3%). Environmental pressures may intensify in Tianjin, Langfang, and Shijiazhuang as they are estimated to be the targets for 65% of all relocated industries. Overall, the results imply that the decentralization strategy is a promising approach for promoting regional sustainable development. The study recommends implementing stricter environmental regulations in the receiving cities.