Water quality permitting: From end-of-pipe to operational strategies

Abstract

End-of-pipe permitting is a widely practised approach to control effluent discharges from wastewater treatment plants. However, the effectiveness of the traditional regulation paradigm is being challenged by increasingly complex environmental issues, ever growing public expectations on water quality and pressures to reduce operational costs and greenhouse gas emissions. To minimise overall environmental impacts from urban wastewater treatment, an operational strategy-based permitting approach is proposed and a four-step decision framework is established: 1) define performance indicators to represent stakeholders' interests, 2) optimise operational strategies of urban wastewater systems in accordance to the indicators, 3) screen high performance solutions, and 4) derive permits of operational strategies of the wastewater treatment plant. Results from a case study show that operational cost, variability of wastewater treatment efficiency and environmental risk can be simultaneously reduced by at least 7%, 70% and 78% respectively using an optimal integrated operational strategy compared to the baseline scenario. However, trade-offs exist between the objectives thus highlighting the need of expansion of the prevailing wastewater management paradigm beyond the narrow focus on effluent water quality of wastewater treatment plants. Rather, systems thinking should be embraced by integrated control of all forms of urban wastewater discharges and coordinated regulation of environmental risk and treatment cost effectiveness. It is also demonstrated through the case study that permitting operational strategies could yield more environmentally protective solutions without entailing more cost than the conventional end-of-pipe permitting approach. The proposed four-step permitting framework builds on the latest computational techniques (e.g. integrated modelling, multi-objective optimisation, visual analytics) to efficiently optimise and interactively identify high performance solutions. It could facilitate transparent decision making on water quality management as stakeholders are involved in the entire process and their interests are explicitly evaluated using quantitative metrics and trade-offs considered in the decision making process. We conclude that the operational strategy-based permitting shows promising for regulators and water service providers alike.

Vulnerability Analysis of Urban Drainage Systems: Tree vs. Loop Networks

“…It is widely used throughout the world for planning, analysis and design related to storm water runoff, combined sewers, sanitary sewers, and other drainage systems in urban areas, with many applications in non-urban areas as well [6,[46][47][48][49][50][51]. …”

“…Furthermore, storage tank provision is used as another adaptation measure for the tree drainage systems to reduce the flood volume. The cost function for tank is adapted from Tao et al (2014) [53] as below C = 2.195 × 10 4 × Volume 0.69 (6) where C is the cost of the tank, Yuan; and Volume is the provided volume of the storage tank, m 3 .…”

“…Urban drainage systems are an increasingly important part of urban infrastructure that conveys stormwater and wastewater away from urban areas and contributes to the general well-being of the urban population [1][2][3][4][5][6]. However, there are pressing challenges in design and operation of urban drainage systems due to climate change, urbanization, population increase and demographic change.…”

Efficiency Evaluation and Policy Analysis of Industrial Wastewater Control in China

“…Although end-of-pipe control is still the focus of wastewater management, theories about regulation water quality in the receiving waters are proposed in a number of countries [4]. Regulating wastewater discharge is the most direct measure to limit passive influences to the environment [5][6][7], but the cost is still somewhat prohibitive [8][9][10][11][12].…”

“…Mathematical models are developed and widely used for evaluating the wastewater treatment [4,12,[24][25][26], including multiple objective optimization ones [27,28]. Based on those theoretical and empirical studies, we intended to construct a Total Factor Efficiency (TFE) model of China's industrial wastewater control practices, and a comprehensive research framework on sustainable development based on theoretical and empirical analysis as well as data of wastewater emission and water pollution control by various industries in China.…”