Connotation Interpretation, Promotion Paths and Engineering Application Verification

Abstract

Under the industrial trend of wastewater treatment upgrading and reconstruction, this paper analyzes the connotation of wastewater treatment operation quality improvement from four dimensions: policy, economy, society and execution, and proposes that the core connotation includes stable high-standard compliance, quality and efficiency enhancement, green ecological development and smart empowerment. To meet the requirements of operation quality improvement, four key implementation directions are put forward: whole-process optimization and upgrading, all-round energy saving and consumption reduction, whole-chain comprehensive utilization, and whole-link smart operation and maintenance. Combined with engineering practice cases, this paper expounds the specific implementation paths and practical effects of each direction, providing theoretical guidance and practical reference for the high-quality development of urban wastewater treatment industry.

1. Introduction

In recent years, quality and efficiency improvement has gradually become a widely concerned hotspot in the wastewater treatment industry, and also a phased national development goal for the wastewater treatment sector. According to urban and rural construction statistics, by 2021, there were 4,594 urban wastewater treatment plants in China, with a total urban wastewater treatment capacity of 247 million m³ per day.

In response to the objective demand of urban wastewater treatment systems in the new era and the standpoint of water ecological environment improvement, the National Development and Reform Commission and the Ministry of Housing and Urban-Rural Development jointly issued the Implementation Plan for Supplementing Shortcomings of Urban Domestic Wastewater Treatment Facilities in August 2020. The plan clearly defines four major tasks: strengthening weak links of urban wastewater treatment plants, supplementing shortcomings of urban wastewater collection pipe networks, accelerating harmless and resourceful sludge treatment, and promoting information system construction, further emphasizing the importance of quality and efficiency improvement of wastewater treatment systems.

This paper analyzes the connotation of wastewater treatment operation quality improvement from four aspects of policy, economy, society and execution, and discusses the specific work directions to realize the improvement of operation quality, providing reference for the upgrading and operation optimization of urban wastewater treatment systems.

2. Connotation of Wastewater Treatment Operation Quality Improvement

To clarify the direction of wastewater treatment operation quality improvement, it is necessary to first define its core connotation, which can be interpreted from four dimensions: policy, economy, society and execution.

2.1 Policy Dimension: Stable High-Standard Compliance

At present, many cities in China still face insufficient wastewater treatment capacity, and the treatment efficiency and quality of some cities need to be further improved. Relevant policies clearly require that wastewater treatment facilities in key regions including the Yangtze River Delta, Guangdong-Hong Kong-Macao Greater Bay Area, Beijing-Tianjin-Hebei region, cities along the main stream of the Yangtze River, provincial capital cities in the Yellow River Basin and cities specifically designated in the state plan must all meet the Class 1A discharge standard.

In addition, environmental management documents have clarified the responsibilities of all parties including local governments, pollutant discharging units and wastewater plant operators, and emphasized the legal responsibility of operators for effluent quality. Relevant tax policies also stipulate that wastewater treatment plants that exceed discharge standards need to pay environmental protection tax, and those punished for environmental violations will be disqualified from VAT immediate refund policy for 36 months.

Driven by a series of policies, the core requirement at the policy level is to improve the risk resistance capacity of wastewater treatment plants and realize all-weather stable high-standard operation, which constitutes the “stable high-standard compliance” connotation of operation quality improvement.

2.2 Economic Dimension: Quality and Efficiency Enhancement

Affected by the global economic situation, fiscal expenditure on environmental governance is facing increasing pressure. The market puts forward higher requirements for cost-effective wastewater treatment services, which is also the core competitiveness of wastewater treatment enterprises. Through a series of quality and efficiency improvement measures, wastewater treatment plants can achieve higher treatment performance with lower operating costs. Therefore, from the economic perspective, the connotation of operation quality improvement is “quality and efficiency enhancement”.

2.3 Social Dimension: Green and Ecological Development

The essence of wastewater treatment is to improve the water environment. In some cases, excessive pursuit of water quality indicators leads to unrealistic standards, making wastewater treatment increasingly dependent on energy and chemical resources. In addition, secondary problems such as sludge and odor from the terminal treatment have also brought negative social impacts.

Under this background, the development of wastewater treatment should return to its original intention of environmental governance, transforming from energy dependence to energy conservation and low carbon, from resource dependence to resource recycling, and from negative environmental impact to environmental friendliness, so as to achieve the goal of green ecological development. Therefore, from the social perspective, the connotation of operation quality improvement is “green ecological development”.

2.4 Execution Dimension: Smart Empowerment

Wastewater treatment needs to balance multiple objectives of stable compliance, cost control and green development. Traditional wastewater treatment, similar to traditional manufacturing, has problems such as low automation level of industrial control systems, simple IT system functions, and decision-making highly dependent on manual experience.

Smart empowerment can promote the transformation of traditional wastewater treatment to smart wastewater treatment, realizing automatic operation and intelligent decision-making, giving full play to the potential of existing facilities and equipment, and providing strong support for quality improvement. Therefore, from the execution perspective, the connotation of operation quality improvement is “smart empowerment”.

3. Promotion Paths of Wastewater Treatment Operation Quality

To achieve the goals of stable high-standard compliance, quality and efficiency enhancement, green ecological development and smart empowerment, four core promotion paths are proposed corresponding to the four connotations.

3.1 Whole-Process Optimization and Upgrading

Whole-process optimization and upgrading focuses on three key aspects: plant-network coordinated operation, operation optimization and regulation, and high-flow shock resistance.

(1) Plant-Network Coordinated Operation

Regulation storage tanks are important buffer facilities to cope with large inflow shocks. In the new round of wastewater upgrading projects in Shanghai, many wastewater treatment plants have been equipped with terminal regulation storage tanks with a storage capacity accounting for 15%–25% of the treatment scale. Operation data shows that regulation storage tanks significantly mitigate instantaneous inflow shocks to wastewater treatment plants. Joint scheduling of drainage pipelines, regulation storage tanks and wastewater plants can effectively cope with high-concentration combined wastewater shocks in the early stage of rainfall, buffer and regulate the influent quality and quantity, and protect the operation safety of wastewater treatment facilities.

(2) Operation Optimization and Regulation

By calibrating the classic activated sludge mathematical model and supplementing with black-box models based on big data analysis, the simulation results can better match the actual operation of wastewater plants. Based on the corrected offline model for simulation calculation, process parameters can be verified, and emergency process scheduling response plans can be refined and optimized. In practice, the model can guide more precise parameter adjustment under shock conditions such as high concentration and large inflow.

(3) High-Flow Shock Resistance Operation Mode

Large inflow shock is a common problem in southern cities with combined drainage systems or incomplete separated systems. A graded response mechanism for high-flow shock should be established, with targeted process adjustment and equipment management measures for different response levels. Through the graded shock resistance regulation measures, the effluent quality can maintain stable and high-standard compliance even under large inflow shocks.

3.2 All-Round Energy Saving and Consumption Reduction

All-round energy saving and consumption reduction is the key to achieving quality and efficiency improvement, focusing on systematic energy consumption management and energy utilization efficiency improvement.

(1) Systematic Energy Saving and Consumption Reduction

Traditional energy saving measures in wastewater plants often focus on individual equipment, but it is difficult to accurately evaluate the implementation effect due to unclear energy consumption base and inaccurate process statistics. It is recommended to build a plant-wide energy management platform, install precise metering devices to conduct detailed statistics of energy consumption of the whole plant, conduct in-depth analysis of power consumption data of each process section and key equipment, and establish standard power consumption benchmarks for each process. Through benchmarking analysis of equipment energy efficiency, the economic and stable operation of equipment can be ensured, and the input-output ratio can be improved.

(2) Improvement of Energy Utilization Efficiency

For plants equipped with sludge drying and incineration processes, system energy balance verification can be carried out. On this basis, a feasible deep utilization scheme for drying tail gas waste heat can be proposed without affecting the normal operation of the drying and incineration system. Taking a sludge treatment plant in Shanghai as an example, after the transformation of carrier gas waste heat utilization of the dryer, the overall energy self-sufficiency rate of the system increased by 8%–10% under unchanged boundary conditions, achieving significant energy saving benefits.

3.3 Whole-Chain Comprehensive Utilization

Whole-chain comprehensive utilization effectively supports the goal of green ecological development, covering three levels: waste resource recycling, space comprehensive utilization and environmental friendliness.

(1) Sludge Residue Resource Utilization

Resource recycling of incineration ash and residue is a key research direction in the industry. Sludge incineration residue has high SiO₂ content, which can be used as cement raw material additive and road base material in the building materials industry. It also has high phosphorus content, which can be recovered for resource utilization.

Taking Shanghai Chengtou Wastewater Co., Ltd. as an example, the company has carried out systematic research on sludge incineration residue resource utilization in cooperation with universities and research institutions. The incineration residue is pretreated and mixed with other raw materials according to the formula to produce iron correction materials and composite fly ash products, which are used as cement raw material additives, clinker admixtures and concrete admixtures. All products meet relevant national and local technical standards. This technology has realized 100% resource utilization of sludge incineration residue, ended the history of sludge incineration residue landfill, and has great promotion value.

(2) Space Comprehensive Utilization

Whole-chain comprehensive utilization also includes the comprehensive utilization of plant space. For example, a semi-underground wastewater treatment plant in Shanghai fully realizes space comprehensive utilization, which is not only environmentally friendly and fully integrated with the surrounding environment, but also practices the sponge city concept, creating a harmonious space between the plant and the surrounding community.

(3) Environmental Friendliness Inside and Outside the Plant

Whole-chain utilization also emphasizes friendly atmospheric environment inside and outside the plant, with focus on odor treatment. Shanghai Chengtou Wastewater has realized full coverage of odor pollution sources, full collection and full treatment of odor, and the odor emission after treatment meets the strictest local standards in China. The company also attaches importance to unorganized odor control inside the plant to build an ecological plant area satisfying employees, and has participated in compiling local standards for odor treatment of wastewater treatment plants, providing technical support for the industry.

3.4 Whole-Link Smart Operation and Maintenance

Whole-link smart operation and maintenance improves the level of smart management and control from three dimensions: “point, block and area”.

(1) “Point” Level: Smart Control of Equipment and Process Sections

The “point” dimension refers to specific equipment and process sections, realizing precise operation of process sections. For example, the development of online automatic sludge index monitoring equipment realizes 24-hour continuous monitoring of sludge index, which greatly supports process judgment. In the pretreatment area, linkage control of facilities such as inlet pump house, regulation storage tank, screens and grit chamber realizes stable influent load of biological tanks, and multiple control modes are set for different working conditions, avoiding manual operation errors and improving emergency response accuracy.

(2) “Block” Level: Plant-Level Digital Twin Smart Factory

The “block” dimension refers to plant-level smart operation that balances high efficiency and green development. Taking the pilot BIM-based digital twin smart factory project as an example, the deep integration of plant BIM, real-time SCADA system data and business system information system data realizes the digitalization of facilities, equipment and production processes. Combined with classic process mechanism models, machine learning black-box models and simulation technology, a multi-dimensional digital model is formed, building an analyzable, simulatable and predictable digital twin factory for scientific and intelligent management.

(3) “Area” Level: Company-Level Comprehensive Management and Control Platform

The “area” dimension refers to the management of the whole region, improving company-level intelligent decision-making. A company-level comprehensive management and scheduling platform is being built, with functions including real-time monitoring, production scheduling, report management, production optimization and precise decision-making. It transforms the traditional plan-task-driven mode into data-task-driven mode, promotes the transformation of management mode from control-oriented to service-oriented, accelerates the technical iteration of operation optimization, and realizes leapfrog operation improvement.

4. Engineering Application Insights

4.1 Applicable Scenarios

The operation quality improvement system is suitable for the following scenarios:

• Upgrading and transformation of urban wastewater treatment plants requiring stable compliance with stricter discharge standards
• Large and medium-sized wastewater treatment plants with high energy consumption pressure and demand for cost reduction and efficiency improvement
• Wastewater treatment plants in sensitive areas with high requirements for odor control and environmental friendliness
• Regional wastewater treatment groups managing multiple plants, requiring unified scheduling and intelligent management

4.2 Key Implementation Points

• Plant-network coordination is the foundation: The quality of influent water is the premise of stable plant operation. Building a joint scheduling mechanism of pipe network, regulation storage and treatment plant can effectively reduce the impact of load fluctuation on the treatment system.
• Systematic energy management is the core: Establishing a full-coverage energy metering system and refining energy consumption indicators of each process section is the basis for tapping energy saving potential, rather than relying on scattered individual energy saving measures.
• Resource utilization is the direction of green development: Sludge, waste heat and plant space are all recyclable resources. Promoting whole-chain resource utilization is the core path to realize low-carbon and environment-friendly wastewater treatment.
• Smart operation is the support: Smart empowerment is the core means to balance multiple objectives of compliance, cost and environmental protection. Layered promotion from single equipment to plant-level and then to regional level is a practical implementation path.

4.3 Operation and Management Recommendations

• Establish graded response mechanisms for common working conditions such as high flow and high concentration load shock, and conduct regular drills to ensure stable effluent under extreme conditions.
• Regularly carry out energy balance accounting of the whole plant, identify high energy consumption links, and implement targeted energy-saving transformation to continuously reduce unit water treatment energy consumption.
• Establish a whole-process odor management system covering source collection, terminal treatment and unorganized emission control, and regularly conduct odor detection inside and outside the plant to maintain good environmental and social benefits.
• Promote the construction of smart operation platforms step by step, start from key process sections, gradually expand to the whole plant and the whole region, and avoid blind investment in informatization that cannot be practically implemented.

5. SYNERAQUA Technical Perspective

At SYNERAQUA, we believe that the improvement of wastewater treatment operation quality is the only way for the industry to transform from scale expansion to high-quality development. The four-dimensional connotation and four promotion paths proposed in this paper are highly consistent with our technical concept of “stable, efficient, green and intelligent” wastewater treatment solutions.

Our integrated smart wastewater treatment solution covers the whole process from plant-network coordinated scheduling, process intelligent optimization, energy consumption fine management to sludge resource utilization. Equipped with our self-developed intelligent operation and management platform, the solution integrates mechanism models and machine learning algorithms, realizes real-time dynamic optimization of process parameters and graded response to load shocks, and reduces comprehensive operating costs by 10–18% while ensuring stable up-to-standard effluent. We also provide full-cycle technical services including energy audit, sludge resource utilization scheme design and smart plant construction, helping wastewater treatment enterprises achieve all-round improvement of operation quality and support the high-quality development of the urban water environment governance industry.

6. Conclusion and Outlook

Improving the operation quality of wastewater treatment is a long-term process that requires continuous practice and accumulation to realize the transformation from quantitative change to qualitative change.

1. The connotation of wastewater treatment operation quality improvement includes four dimensions: stable high-standard compliance at the policy level, quality and efficiency enhancement at the economic level, green ecological development at the social level, and smart empowerment at the execution level, which jointly define the development goals of the industry in the new era.
2. Four core paths to improve operation quality are proposed: whole-process optimization and upgrading to achieve stable compliance, all-round energy saving and consumption reduction to improve economic benefits, whole-chain comprehensive utilization to realize green development, and whole-link smart operation and maintenance to provide technical support.
3. Engineering practice cases verify the feasibility and effectiveness of each promotion path. Through the coordinated promotion of the four directions, wastewater treatment plants can achieve comprehensive quality improvement of operation, and better play the main role of water environment governance.

With joint efforts of the industry, the operation quality of wastewater treatment plants will continue to improve, and finally realize the comprehensive goals of stable high-standard operation, cost-effective treatment, green and low-carbon development, and intelligent operation management.

FAQ

Q1: What are the core objectives of urban wastewater treatment operation quality improvement?
The core objectives include four aspects: first, stable high-standard compliance, ensuring all-weather stable effluent meeting discharge standards and improving anti-risk ability; second, quality and efficiency enhancement, improving treatment effect while reducing operating costs and achieving cost-effective wastewater treatment services; third, green ecological development, reducing energy and resource consumption, realizing resource recycling and environmental friendliness; fourth, smart empowerment, improving automation and intelligent decision-making level through digital and intelligent transformation.

Q2: Why is plant-network coordinated operation emphasized in whole-process optimization?
The operation stability of wastewater treatment plants is highly dependent on the influent conditions. In combined drainage systems, rainfall will cause large instantaneous flow and high concentration shock, which seriously impacts the normal operation of the biochemical system. Through the joint scheduling of pipe network, regulation storage tank and treatment plant, the influent quality and quantity can be buffered and adjusted, which effectively protects the operation safety of the treatment system and is the premise of stable effluent quality.

Q3: What are the key points of systematic energy saving and consumption reduction in wastewater treatment plants?
The first is to establish a precise energy metering system to clarify the energy consumption base and distribution of each process section, which is the basis for energy saving analysis. The second is to establish standard energy consumption benchmarks for each process and equipment, and tap energy saving potential through benchmarking management. The third is to optimize from the system level, such as waste heat recovery and utilization of sludge drying and incineration systems, to improve the overall energy utilization efficiency, rather than only focusing on individual equipment energy saving.

Q4: What are the three levels of smart operation and maintenance construction?
Smart operation and maintenance is promoted layer by layer from “point, block to area”. The “point” level focuses on the intelligent control of single equipment and process sections to realize precise operation; the “block” level focuses on plant-level digital twin construction to realize intelligent management of the whole plant; the “area” level focuses on the regional comprehensive management and control platform to realize unified scheduling and optimized decision-making of multiple plants. This layered construction mode conforms to the actual needs of the industry and can effectively avoid the problem that large-scale informatization construction is divorced from actual operation.