Sewage treatment cost is a core issue in the field of environmental governance, which is not only related to the compliance operation costs of enterprises but also affects the sustainability of urban ecological environment governance. Currently, against the backdrop of the normalized tightening of environmental policies, rapid iteration of sewage treatment technologies, and continuous innovation in market models, profound changes are taking place in the composition, pricing logic, and optimization paths of sewage treatment costs. From multiple perspectives such as policy orientation, technology selection, market models, and regional differences, this article comprehensively analyzes the core influencing factors of sewage treatment costs and practical optimization solutions, providing professional references for industry practitioners, enterprise managers, and relevant decision-makers.

I. Core Impact of New Policies on Sewage Treatment Costs: Compliance Costs Become a Key Variable

Environmental policies are the core lever for regulating sewage treatment costs. In 2024, a number of new policies have been implemented, directly promoting the adjustment of the sewage treatment cost structure, with the proportion of compliance costs continuing to increase.

1. Upgraded Discharge Standards Force Cost IncreasesThe draft for comments on the revision of Discharge Standards for Pollutants from Urban Sewage Treatment Plants (GB 18918-2002) has been released, and some regions have already implemented stricter effluent standards in advance (e.g., COD ≤ 30mg/L, total phosphorus ≤ 0.3mg/L). To meet the new standards, sewage treatment plants need to add advanced treatment units (such as ozone oxidation and activated carbon adsorption), resulting in a 20%-40% increase in construction investment and a 0.5-1.2 yuan rise in operating cost per ton of water.

2. Dual Constraints from Environmental Tax and Carbon PoliciesThe environmental tax is levied based on pollutant concentration. Exceeding the pollutant concentration standards will face a 2-5 times tax surcharge, directly forcing enterprises to improve sewage treatment efficiency. At the same time, the carbon peaking policy promotes energy-saving transformation of sewage treatment plants. Although the application of low-carbon technologies such as photovoltaic power supply and waste heat recovery increases investment in the short term, it can reduce energy consumption costs in the long run. Some projects have already achieved a win-win situation of carbon emission reduction and cost optimization.

3. Subsidy Policies Tilt towards Resource UtilizationCurrent subsidy policies no longer solely support sewage treatment itself, but focus on projects such as reclaimed water reuse and sludge resource utilization. For example, industrial enterprises with a reclaimed water reuse rate of more than 50% can enjoy an operating subsidy of 0.5-1.0 yuan per ton. Sludge that is made into organic fertilizer and used up to standard can receive special subsidies, directly offsetting part of the treatment costs.

II. Connection between Technology Selection and Sewage Treatment Costs: Choosing the Right Solution Saves Unnecessary Expenses

The selection of sewage treatment technology directly determines the cost level. The cost difference between different technical paths can be several times, so it is necessary to accurately match according to water quality, scale, and discharge standards.

1. Traditional Processes vs. New Processes: Cost Difference Comparison

• Traditional processes (activated sludge process, oxidation ditch): Suitable for low-concentration domestic sewage, with low construction costs (300-800 yuan per ton of water for construction), but high operating energy consumption (0.8-1.2kWh per ton of water for electricity consumption) and large chemical consumption, suitable for large-scale municipal sewage plants.
• New processes (MBR, MBBR, short-cut nitrification and denitrification): High treatment efficiency, and the effluent can be directly reused. The operating energy consumption per ton of water is reduced by 30%-50%, but the procurement cost of core equipment such as membrane modules is high (800-1500 yuan per ton of water for construction), suitable for scenarios with high discharge standards or reuse needs.
• Ecological processes (constructed wetlands, biological filters): Suitable for rural areas or low-concentration sewage, with extremely low operating costs (0.3-0.8 yuan per ton of water), but large floor space, long treatment cycle, and significant impact from the natural environment.

2. Optimization Effect of Intelligent Technology on CostsThe application of intelligent and digital technologies has become a key means to reduce sewage treatment costs:

• Online water quality monitoring system: Captures real-time changes in indicators such as COD and ammonia nitrogen, dynamically adjusts chemical dosage and equipment operating parameters, reducing chemical waste by 15%-25%.
• Internet of Things + remote operation and maintenance: Realizes equipment fault early warning and intelligent scheduling, reduces manual inspection costs, and lowers equipment downtime losses, which can reduce operation and maintenance costs by 10%-18%.
• Big data optimization model: Optimizes the combination of process parameters by analyzing historical operation data, achieving a balance between energy consumption and treatment effect. In some projects, the cost per ton of water has decreased by 0.3-0.6 yuan.

III. Market Model Innovation: How to Reduce Sewage Treatment Costs through Model Optimization?

In addition to technology and policies, the innovation of market operation models also provides a new path for the optimization of sewage treatment costs, with significant differences in cost logic between different models.

1. PPP Model: Sharing Construction Costs and Improving Operation EfficiencyThe PPP model (Public-Private Partnership) is widely used in municipal sewage treatment projects, where social capital is responsible for construction and operation, and the government pays service fees based on the amount of treated water. This model can reduce the government's short-term fiscal pressure, and at the same time, through the professional operation and maintenance of social capital, the operating cost per ton of water is reduced by 10%-20%. Currently, the service fee per ton of water for municipal PPP projects in first-tier cities is mostly 1.2-2.5 yuan.

2. Park Centralized Treatment Model: Achieving Cost Reduction through Scale EffectIndustrial parks adopt the "centralized collection + unified treatment" model, where multiple enterprises share sewage treatment facilities to exert scale effects:

• Sharing of construction costs: Individual enterprises do not need to invest in separate facility construction, but only need to pay for connecting to the pipe network and treatment fees, reducing construction costs by 60%-80%.
• Improvement of treatment efficiency: Customized treatment processes are developed according to the industrial characteristics of the park, avoiding redundant construction and inefficient treatment. The cost per ton of water is 30%-45% lower than that of enterprises building their own facilities.

3. Third-Party Entrusted Operation and Maintenance: Reducing Hidden Costs through ProfessionalismMany enterprises choose to entrust their sewage treatment facilities to professional third parties for operation and maintenance, with core advantages as follows:

• Professional teams can optimize chemical selection and equipment operating parameters, reducing ineffective consumption.
• It avoids penalty costs caused by risks such as equipment failures and substandard water quality. After entrustment, the comprehensive costs of some enterprises are reduced by 15%-25%.

IV. Regional Differences in Sewage Treatment Costs: Which Factors Determine Regional Costs?

There are significant differences in sewage treatment costs among different regions in China. The core driving factors include economic level, resource prices, and policy intensity. The regional references in 2024 are as follows:

1. East China and South China: High Costs Match High Standards

• Cost per ton of water: 1.5-3.2 yuan/ton for municipal domestic sewage, 8-20 yuan/ton for general industrial sewage, and 25-65 yuan/ton for high-difficulty industrial sewage.
• Core reasons: The strictest environmental standards, high electricity prices (0.6-0.8 yuan/kWh) and labor costs, high requirements for harmless sludge disposal (300-500 yuan/ton for disposal), and tight land resources leading to high construction costs.

2. North China and Central China: Moderate Costs with Tightening Policies

• Cost per ton of water: 1.0-2.5 yuan/ton for municipal domestic sewage, 6-15 yuan/ton for general industrial sewage, and 20-50 yuan/ton for high-difficulty industrial sewage.
• Core reasons: The policy intensity is between that of the eastern region and the central and western regions, with moderate resource prices. Some regions are key areas for coordinated governance of the Beijing-Tianjin-Hebei region, so the costs are slightly higher than those of surrounding areas.

3. Northwest and Southwest China: Low Costs with Strong Subsidies

• Cost per ton of water: 0.8-1.8 yuan/ton for municipal domestic sewage, 5-12 yuan/ton for general industrial sewage, and 18-45 yuan/ton for high-difficulty industrial sewage.
• Core reasons: Low electricity prices (0.3-0.5 yuan/kWh) and labor costs, abundant land resources, and local governments provide relatively high construction and operation subsidies to promote environmental governance.

V. Practical Optimization Skills for Sewage Treatment Costs in 2024: Applicable to Both Enterprises and Municipalities

Both enterprise and municipal sewage treatment projects can achieve cost optimization through the following practical skills, balancing environmental protection and economy.

1. Enterprise Side: Full-Process Cost Reduction from Source to End

• Optimization of production processes: Adopt clean production technologies to reduce the amount of sewage generated and pollutant concentration. For example, chemical enterprises using circulating water systems can reduce the treatment load by more than 30%.
• Classified and diverted treatment: Separate high-concentration sewage from low-concentration sewage for treatment. High-concentration sewage adopts efficient processes in a targeted manner, and low-concentration sewage uses simplified treatment processes to avoid cost waste caused by "one-size-fits-all" treatment.
• Alignment with subsidy policies: Proactively apply for relevant subsidies for reclaimed water reuse and sludge resource utilization, sort out policies such as environmental tax reductions and exemptions and equipment investment tax credits in the region, and maximize policy dividends.

2. Municipal Side: Dual-Drive of Scale and Intelligence

• Pipe network optimization: Promote the transformation of rainwater and sewage diversion, reduce the false increase in treatment scale caused by rainwater mixing, and lower energy consumption and chemical consumption.
• Facility integration: Integrate small sewage treatment stations into regional centralized treatment plants to exert scale effects, which can reduce the cost per ton of water by approximately 30%.
• Low-carbon transformation: Use the idle space of sewage treatment plants to build photovoltaic power stations, and equip with waste heat recovery systems to self-supply part of the electricity demand and reduce energy consumption costs.

VI. Future Trends: Sewage Treatment Costs Will Show the Dual Characteristics of "Cost Reduction + Value Enhancement"

Looking forward to the next 3-5 years, sewage treatment costs will show two core trends driven by technological progress, model innovation, and policy guidance:

• Continuous deepening of technological cost reduction: The localization rate of membrane materials and energy-saving equipment will be further improved, and biological treatment technologies will be optimized and upgraded, leading to an overall 10%-15% reduction in the cost per ton of water treatment.
• Continuous expansion of value-added space: Models such as reclaimed water reuse, sludge resource utilization, and energy recovery will become mainstream. Some projects can cover more than 50% of the treatment costs through resource value-added, and even achieve profitability.
• More mature market-oriented pricing: Industrial sewage treatment will form a refined model of "water quality pricing + service pricing", and municipal sewage treatment will gradually introduce more market competition to promote the optimization of the cost structure.

Conclusion

The control of sewage treatment costs is not simply "cost reduction", but finding the best balance between policy compliance, technology adaptation, and market rules. As environmental governance enters a stage of high-quality development, the optimization of sewage treatment costs will increasingly rely on technological innovation, model upgrading, and refined management. Enterprises and relevant units need to keep up with policy trends, accurately match treatment technologies, make full use of market resources, and while fulfilling environmental responsibilities, minimize comprehensive costs.