How Secondary Sewage Treatment Supports the Circular Water Economy?
Water scarcity is an increasingly pressing issue worldwide, driven by growing populations, industrial expansion, and climate change. As a result, sustainable water management practices are more crucial than ever. One of the most impactful strategies in this space is the circular water economy, which focuses on maximizing water reuse and minimizing waste. At the heart of this approach lies secondary sewage treatment—a critical step in transforming wastewater into a valuable resource.
Before diving into its role in the circular water economy, it’s essential to understand what is the key difference between primary and secondary sewage treatment. While primary treatment involves the physical removal of large solids and sedimentation of suspended particles, secondary sewage treatment focuses on removing dissolved organic matter through biological processes. This step is vital for ensuring the treated water is safe for reuse or further purification.
Understanding Secondary Treatment of Sewage
The secondary treatment of sewage is a biological process that uses bacteria and other microorganisms to break down organic pollutants in wastewater. After the primary treatment removes heavy solids and scum, the wastewater still contains dissolved and fine organic material. During secondary treatment, this is significantly reduced through methods such as activated sludge systems, trickling filters, and bio-towers.
By relying on naturally occurring biological agents, secondary treatment efficiently reduces biochemical oxygen demand (BOD) and suspended solids. This not only prevents environmental pollution when the water is discharged but also prepares it for tertiary treatment or safe reuse.
Supporting the Circular Water Economy
The circular water economy is built on the principle of treating wastewater not as waste, but as a resource. Secondary sewage treatment plays a key role in this model by enabling large volumes of wastewater to be safely reused for industrial, agricultural, or even municipal applications.
Instead of discharging treated wastewater into rivers or seas, industries and utilities are increasingly investing in water recovery and reuse. Secondary treatment ensures that the water is clean enough to be redirected toward non-potable uses, such as:
- Industrial cooling and processing
- Landscape irrigation
- Agricultural irrigation
- Toilet flushing in residential and commercial buildings
The Difference Between Primary and Secondary Sewage Treatment
Understanding the difference between primary and secondary sewage treatment is key to recognizing their roles in the overall treatment process. Primary treatment is largely mechanical and removes only physical impurities. It’s the first stage where solids settle, and oil and grease are skimmed off. However, it does not eliminate dissolved organic pollutants.
Secondary treatment of sewage, on the other hand, uses biological methods to decompose and remove organic matter that cannot be settled out during primary treatment. This makes it a more advanced and essential step, particularly when the goal is water reuse and alignment with circular economy principles.
Environmental and Economic Benefits
Beyond supporting the circular economy, secondary sewage treatment also offers direct environmental and economic advantages:
- Reduces Pollution: Treated water released into natural bodies is much less harmful, protecting aquatic ecosystems and human health.
- Supports Water Scarcity Solutions: Clean water can be reused, reducing dependence on freshwater sources.
- Cost Savings: Municipalities and industries save on water procurement and avoid penalties for environmental violations.
- Enhances Sustainability Goals: Corporations and governments alike can meet sustainability targets by investing in advanced wastewater treatment solutions.
Real-World Examples of Circular Water Systems
Countries like Singapore, the Netherlands, and Israel have integrated secondary sewage treatment into their national water strategies. In Singapore, for example, reclaimed water known as NEWater is produced through advanced secondary and tertiary treatment, and it’s reused for both industrial and potable purposes. Such initiatives prove that a circular water economy is not only viable but also scalable.
Industries, too, are playing a big part. Food and beverage manufacturers, textile companies, and power plants are adopting water reuse systems driven by secondary sewage treatment. These efforts not only ensure operational continuity during water shortages but also demonstrate environmental responsibility.
Ion Exchange’s Advanced Sewage Treatment Solutions
Ion Exchange is a leading provider of innovative water and wastewater treatment solutions. Their advanced range of sewage treatment plants is designed to meet the diverse needs of the country’s growing population and industrial sectors. With a focus on sustainability and efficiency, Ion Exchange offers customized solutions that incorporate the latest technologies, ensuring optimal performance and environmental compliance.
INDION New Generation Packaged Sewage Treatment Plant (NGPSTP)
It is a state-of-the-art solution that combines the innovative technologies of lamella plate clarification and aeration, resulting in a highly efficient, ready-to-operate, prefabricated system for sewage treatment. This all-in-one single-tank packaged system is designed with a modular capacity ranging from 10 to 100 m3/d, making it both compact and user-friendly. Not only does it deliver high-quality effluent, but it also boasts features that cater to the specific needs of modern facilities. The NGPSTP’s advantages include minimal land usage, reduced power and chemical requirements, and low operating costs, making it an ideal choice for a wide range of applications while ensuring environmental sustainability and cost-effectiveness.
INDION NGPSTP-NRÂ
It is an advanced sewage treatment solution that combines a fixed film reactor with lamella clarification, resulting in a high-performance, prefabricated system that is ready to operate. This all-in-one, modular design offers compact and simple operation with minimal maintenance. Built with an MS tank lined with FRP, it ensures no corrosion, delivering high-quality effluent while being efficient and easy to manage.
Sequencing Batch Reactor (SBR)Â
It is an advanced activated sludge process that operates in true batch mode, with both aeration and sludge settlement occurring within the same tank. Unlike conventional continuous-flow systems, which separate these functions into different spaces, the SBR performs them in a time sequence, offering greater flexibility. This design allows the SBR to handle varying influent volumes, making it adaptable to changing conditions, unlike the continuous system, which relies on a fixed flow rate.
Advanced Fluidized Media Reactor (AFMR) system
It is a compact SINGLE TANK DESIGN UNIT that integrates an aeration tank with floating media, a lamella settler, and a chlorine contact tank. The AFMR media boasts a high surface area, excellent physical and chemical resistance, and minimal annual losses. INDION’s Advanced FMR offers significant advantages, including reduced space requirements, lower power consumption due to the elimination of sludge recirculation, and minimal maintenance thanks to its design without moving mechanical parts.
Conclusion
Secondary sewage treatment is more than just a stage in wastewater management—it’s a bridge to a sustainable, circular water economy. By transforming wastewater into a reusable resource, this process supports water conservation, protects ecosystems, and creates long-term economic value.
