2 Tanks 11800m³ Wastewater Treatment & Sewage Storage Project

Design and Engineering Solutions for Corrosion Protection

Planning Wastewater Tank Capacity

Developed in Chengdu, Sichuan Province in 2021, this wastewater treatment project was contracted by an industrial construction company specializing in the development of wastewater treatment infrastructures. Engineering, fabrication and installation of two large-diameter steel tanks, designed for wastewater storage, process balancing and sedimentation within the treatment process, were included in the project.

In wastewater treatment facilities, tank capacity impacts hydraulic retention time, process stabilization and emergency storage. During project development, the storage volume was determined by the daily flow of wastewater, peak inflow variations and the maintenance reserve. In facilities with an approximate daily flow rate of 500 m³/day to 2,000 m³/day, equalization and storage tanks are designed with reserve capacities to provide an emergency allowance for 12 to 24 hours of process flow.

The design team analyzed the sedimentation wastewater quality in terms of suspended solids concentration, pH, and seasonal flow. Based on the aforementioned, the flexible design of the two steel tanks was considered. Compared to concrete, steel storage tanks offer site construction time savings of 30% to 40% and allow design flexibility for future expansions.

Key Features of the Structural Design

• Tank Diameter Optimization: Configurations with larger diameters help to minimize the total footprint of the storage tanks and simplify the design of the supporting pipe networks.
• Foundation Load Distribution: The design of the tank foundation considered several hundred tons of full liquid loads.
• Wind and Seismic Resistance: Regional wind and seismic requirements and the requirements for the safety of the operation of the tank were addressed.
• Ease of Maintenance: The design of the storage tank considered the need for routine maintenance through the provision of inspection walkways, access ladders, and service openings.

In order to create the structural system, shell sections were reinforced. For areas with lower stress, thinner steel plates were used. Finite load calculations were conducted to determine thickness requirements for long-term reliability. For the expected lifespan of more than 20 years, the risks of deformation were eliminated through the proper distribution of loads across the tank shell and foundation.

Corrosion Protection Design in High Humidity Wastewater

There are many challenges to creating and maintaining a robust system in the treatment of wastewater as the environment catalyzes the rapid corrosion of system components. Coupled with the continuous exposure to moisture, the presence of hydrogen sulfide and chloride and the biotic layer act to ensure that without protection, corrosion will threaten the integrity of the tank and raise maintenance costs.

This project utilized a multi-layered, anti-corrosion treatment on the both the inside and outside of the tank to enhance protection. The preparation of the surface was the equivalent of Sa2.5, to ensure a strong bond for the protection to keep reinforced and to improve the lifespan of the treatment.

This design provides a protection system for moisture, chemicals, and biological corrosion. While the tank operates under normal requirements, the treatment of corrosion will be required in over a decade, which will lower maintenance costs for the water handling tank.

Liquid Level Automation System Design

For effective treatment and management of wastewater, controlling liquid levels and ensuring persistent monitoring of operations is crucial. Consequently, most modern wastewater tanks are furnished with automated instrumentation to enhance stability of processes and minimize the need for manual operations.

This project set aside ports for various intelligent monitoring systems, including but not limited to, ultrasonic level sensors, pressure transmitters, and remote alarm systems. For such systems, the accuracy of liquid level measurements may be as good as ±0.25%, with the time intervals for monitoring defined as real-time.

A SCADA (Supervisory Control And Data Acquisition) enabled system would allow for centralized control to monitor tank levels, the status of pumps, and overflow alarms. Automation of control improves the efficiency of the wastewater treatment process by reducing the time of response to abnormal situations.

Get in touch with our design and engineering department for a custom-designed, cost-effective, reliable, and efficient steel silo solution.

How Steel Tanks Minimize the Risk and Cost of Maintenance for Wastewater Treatment

Corrosion Prevention for the Long-Term

Corrosion is one of the major causes of downtime and maintenance costs for Wastewater Treatment Facilities. A lifecycle protection plan starts with selecting the right material, specifying the right coatings, optimizing drainage, and planning inspections.

In this project, the seams of highly welded structures, as well as the inlets and liquid-air interfaces, were given special protection. Coupled with inspections every 6 to 12 months, this will result in a significant reduction in the need for repairs, while extending the life of the structures beyond 20 years.

Optimized Management of Wastewater Storage Safety

Safety during management operations relies on safe storage of sufficient liquid levels. Additionally, Overseer devices, monitored emergency reserve capacity, and access control systems enhance safety.

Annual structural assessments, monthly checks of devices, and constant assessments of critical parameters are part of most safety management plans. These measures help keep operational risks low and ensure compliance with environmental protection.

Automated Monitoring To Reduce Operating Costs

Automation helps reduce labor and increase the consistency of a process. Real-time monitoring can help operators recognize sudden changes in liquid levels, disruptions in equipment, or disruptions in the process, before developing an incident that incurs high costs.

The following describes the benefits that arise due to automation:

• Reduced Manual Inspection Frequency: remote monitoring reduces labor costs due to an increased need for site inspections.
• Faster Fault Detection: abnormal conditions prompt immediate alarm and notification.
• Process Stability Improvement: Wastewater Treatment sustainability is reinforced due to ongoing stabilization monitoring.
• Lower Lifecycle Costs: Infrastructure is safeguarded from unplanned, costly repairs due to sustained Predictive Maintenance.

Facilities that have implemented automated monitoring systems have been able to decrease maintenance costs by 15% to 30% with an associated increase in operational reliability.

From engineering and design through construction, we provide turnkey steel silo EPC solutions tailored to your materials, capacity, and production requirements. Contact us to obtain your engineered construction documents.

Innovative Trends in the Development of Wastewater Storage and Treatment Solutions

• Current Trends in Modular Tank Construction
  

  Modular construction of steel tanks is winning out over traditional construction methods due to the speed and ease with which construction can be completed. Compared to a conventional cast-in-place structure, modular systems can cut onsite construction time by 25% to 50% and are much easier to expand.

• Future Trends of Digital Operational Monitoring
  

  An increasing number of digital operational frameworks are combining networked sensors, cloud-based data, and predictive maintenance analytics. With the right tools, a facility may collect hundreds, if not thousands, of data points each day, thereby greatly enhancing the efficiency and precision of maintenance.

• Development of Green, Low Maintenance Wastewater Facilities
  

  Compliance with environmental regulations is driving the creation of durable, low maintenance wastewater infrastructure. Future designs of wastewater treatment tanks will stress low energy and resource costs, infrequent maintenance, and extended service life of coatings. Integrated, smart monitoring systems, modular construction, and improved corrosion protection will be found in all modern wastewater treatment systems.

  Contact us to see how our steel silo systems can help you reduce loss and automate systems with a quick ROI for your bulk storage project.