Access to clean, safe, and reliable water is fundamental for modern society—be it for drinking, industrial use, or environmental discharge. With growing population densities, industrialization, and regulatory pressures, advanced water treatment systems are becoming indispensable. These systems employ a series of physical, chemical, and biological processes to purify raw or contaminated water to meet stringent quality standards.
This article provides a comprehensive technical guide to advanced water treatment, with a strong focus on screening systems and UV disinfection—two critical pillars of both drinking and wastewater treatment infrastructure.
Introduction: Why Advanced Water Treatment Matters
Key Drivers:
Urban population growth and limited freshwater resources
Industrial discharges with complex contaminants
Waterborne diseases due to inadequate sanitation
Climate change impacting water availability and quality
Regulatory compliance (e.g., CPCB, EPA, BIS, WHO)
Objective of Advanced Treatment Systems:
Provide safe drinking water
Facilitate wastewater reuse in agriculture and industry
Ensure compliance with discharge norms
Reduce chemical footprint
Promote energy and cost efficiency
Overview of the Water Treatment Process
1. Preliminary Treatment: Screening and Grit Removal
This is the first line of defense in any treatment plant. Large solids like plastics, rags, sticks, and sand are physically removed using bar screens, drum screens, and grit chambers. This step protects downstream equipment from abrasion, clogging, and mechanical damage, ensuring smooth plant operation.
2. Primary Treatment: Sedimentation and Flotation
In this stage, water is held in primary clarifiers or settling tanks, allowing suspended solids to settle by gravity. Some systems also use dissolved air flotation (DAF) to remove oils, fats, and lighter solids. This step reduces the organic and solid load before biological treatment.
3. Secondary Treatment: Biological Oxidation
This is the core treatment stage, where dissolved organic matter is biologically broken down by microorganisms in aeration tanks. Common processes include:
ASP (Activated Sludge Process): Microbes digest organic pollutants in aerated reactors.
MBBR (Moving Bed Biofilm Reactor): Uses biofilm-coated media for high efficiency in smaller footprints.
SBR (Sequencing Batch Reactor): A batch process that combines aeration and sedimentation in a single tank.
This stage significantly lowers BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand).
4. Tertiary Treatment: Filtration and Chemical Polishing
This stage removes residual suspended solids, nutrients, and trace contaminants using technologies like:
Pressure sand filters (PSF) and dual media filters (DMF)
Activated carbon filters (ACF) for odor, color, and organic compound removal
Chemical dosing (e.g., alum, lime, polymers) for polishing and phosphorus removal
Tertiary treatment ensures the effluent meets high-quality standards for reuse or discharge.
5. Disinfection: UV, Chlorine, or Ozone Disinfection
The final stage ensures pathogen-free water by killing or inactivating bacteria, viruses, and protozoa. Methods include:
UV disinfection: Non-chemical, fast, and residue-free
Chlorination: Provides residual protection, especially for distribution systems
Ozonation: Powerful oxidant that breaks down even resistant microorganisms
This step is crucial for public health protection and regulatory compliance.
Advanced Water Treatment Add-ons
Membrane Filtration (UF/RO/NF)
Membranes act as physical barriers that remove suspended solids, microorganisms, and dissolved salts:
UF (Ultrafiltration): Removes bacteria and colloids
NF (Nanofiltration): Removes divalent salts, organic molecules
RO (Reverse Osmosis): Removes almost all dissolved salts and impurities
Used for water reuse, desalination, and high-purity water applications.
Ion Exchange
This chemical process removes specific ions, like calcium, magnesium (for softening), or heavy metals. Common in boiler feedwater treatment, demineralization, and groundwater purification.
Advanced Oxidation Processes (AOPs)
AOPs combine strong oxidants like ozone, hydrogen peroxide, and UV to generate hydroxyl radicals, which degrade emerging contaminants, pharmaceuticals, and non-biodegradable organic pollutants. Ideal for micropollutant destruction in wastewater reuse applications.
Nutrient Removal (Nitrogen & Phosphorus)
Essential for preventing eutrophication in receiving water bodies. This involves:
Nitrification and denitrification for nitrogen removal
Chemical precipitation (e.g., alum, ferric chloride) or enhanced biological phosphorus removal (EBPR)
Used in municipal STPs and industrial effluent systems with nutrient discharge limits.
Sludge Dewatering and Disposal
All treatment processes generate sludge that must be handled safely. Technologies like filter presses, centrifuges, or belt presses are used to reduce sludge volume before disposal. Proper sludge management ensures hygienic operation, odor control, and regulatory compliance.
Screening in Water and Wastewater Treatment
What is Screening?
Screening is the first line of defense in any water or wastewater treatment plant. It involves the mechanical separation of large solids and debris from the water stream.
Purpose:
Protect pumps, valves, membranes, and sensors
Prevent clogging and wear in downstream systems
Improve operational reliability and efficiency
Types of Screens
| Type | Opening Size | Typical Materials Removed | Applications |
|---|---|---|---|
|
Coarse Screens |
> 6 mm (Bar spacing) |
Plastics, bottles, rags, wood, large leaves |
Municipal STPs, headworks |
|
Fine Screens |
1–6 mm |
Hair, seeds, small plastic particles |
Pre-filtration in ETPs and MBR systems |
|
Micro Screens |
< 1 mm |
Algae, fine sand, suspended solids |
Tertiary treatment, water reuse systems |
Screening Mechanisms:
Manual Bar Screens: Low-cost, labor-intensive
Mechanically Cleaned Bar Screens: Automated, continuous operation
Drum Screens / Rotary Screens: Cylindrical or disc-shaped, used for fine and micro screening
Step Screens: Stair-shaped screens with self-cleaning action, used in compact plants
Screen Cleaning and Disposal
Automatic Rake Mechanism: Removes accumulated solids from screen surface
Backwashing/Spray Nozzles: Clean fine and micro screens
Screenings Handling: Transported to compactor, dewatered, and disposed to landfills or incineration
Design Parameters
| Parameter | Typical Range |
|---|---|
|
Approach Velocity |
0.6 – 1.2 m/s (to avoid clogging) |
|
Bar Spacing (Coarse) |
6 – 75 mm |
|
Bar Spacing (Fine) |
1 – 6 mm+ |
|
Head Loss |
0.2 – 0.6 m (varies with loading) |
|
Screen Inclination |
60°–75° for bar screens |
UV Disinfection: Chemical-Free Sterilization
What is UV Disinfection?
Ultraviolet (UV) disinfection is a physical method of sterilization that uses short-wavelength UV-C radiation (200–280 nm) to inactivate microorganisms by damaging their nucleic acids (DNA/RNA).
Working Principle
Water passes through a UV reactor containing low- or medium-pressure mercury lamps that emit UV-C light. The radiation penetrates microbial cells, breaking the DNA strands and preventing replication.
| Parameter | Typical Value |
|---|---|
|
UV Dose (Drinking Water) |
30–40 mJ/cm² |
|
UV Dose (Wastewater) |
80–150 mJ/cm² |
|
Lamp Wavelength |
254 nm (germicidal peak) |
|
Inactivation Efficiency |
>99.99% for bacteria/viruses |
Advantages of UV Disinfection
✅ No Chemicals Added: No residuals like chlorine
🔄 No Taste or Odor Change: Maintains water aesthetics
⚡ Instantaneous Action: No contact time needed
🧼 Low Maintenance: Lamps replaced annually; minimal moving parts
🌱 Sustainable: No DBPs (Disinfection By-Products), no storage hazards
Types of UV Systems
| System Type | Lamp Type | Application |
|---|---|---|
|
Low-Pressure UV |
Low pressure, low intensity |
Municipal water supply, POU filters |
|
Medium-Pressure UV |
High intensity, wide spectrum |
Industrial effluent, wastewater reuse |
|
Closed-Vessel |
Pressurized chamber |
Potable water treatment plants (WTPs) |
|
Open-Channel |
Submerged lamps in channels |
Municipal STPs and ETPs |
Operational and Design Considerations
Transmittance (UVT): Should be >70% for effective disinfection
Lamp Fouling: Addressed by automatic quartz sleeve cleaning
Hydraulic Design: Proper mixing, no short-circuiting
Redundancy: Typically 2–3 units in parallel for continuous flow
Monitoring: UV intensity sensors, temperature sensors, and flow meters
Advanced Wastewater Treatment Integration
Typical Stages in Modern WWTPs:
Preliminary – Screens, grit chambers
Primary – Clarifiers or settling tanks
Secondary – Aeration (ASP, MBBR, SBR)
Tertiary – Sand/Pressure/Disc Filters, Membranes
Disinfection – UV/Ozone/Chlorine
Sludge Treatment – Thickening, dewatering, digestion
Tertiary Add-ons:
Membrane Bioreactors (MBR): Biological + membrane filtration
Reverse Osmosis (RO): Desalination, reuse systems
Activated Carbon Filters: Organic compound removal
AOPs (UV/H₂O₂/Ozone): Micropollutant degradation
Key Applications of Advanced Water Treatment Systems
Municipal Water and Wastewater Plants
Hospitals, Hotels, and Institutions
Data Centers and Semiconductor Industries
Desalination and Zero Liquid Discharge (ZLD) Facilities
Monitoring, Automation, and Compliance
Modern systems are integrated with SCADA (Supervisory Control and Data Acquisition) for remote monitoring and control, enabling:
Real-time tracking of flow, pH, turbidity, TDS, DO
Remote control of valves, pumps, UV reactors
Alerts for equipment failure or water quality deviations
Data logs for regulatory audits and reporting
Conclusion: Building a Water-Secure Future
From screening that protects treatment infrastructure to UV disinfection that ensures microbial safety, every step in the water treatment process plays a critical role in delivering safe, sustainable, and high-quality water.
Advanced water treatment systems are not just optional upgrades—they are essential solutions in a world where water scarcity, pollution, and regulatory pressure are increasing. Modern systems must be efficient, low-maintenance, environmentally responsible, and built to last.
One such example is the SUSBIO range of smart water treatment technologies, which offers robust solutions for both centralized and decentralized applications. The SUSBIO ECOTREAT system, in particular, combines advanced screening, biological treatment, and UV disinfection into a compact, modular design—perfect for residential complexes, commercial buildings, and institutional facilities.
By adopting technologies like SUSBIO ECOTREAT, users can ensure:
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Regulatory compliance (CPCB/BIS/WHO)
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Space- and energy-efficient operation
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Long-term sustainability and water reuse readiness
Take Action: Upgrade Your Water Treatment System Today
Whether you’re planning a new facility or retrofitting an existing one, we can help you implement high-performance solutions in screening systems, UV disinfection, membrane filtration, and smart automation.
🔗 Contact Us today to explore how SUSBIO ECOTREAT and other advanced technologies can help you build a future-ready, compliant, and sustainable water treatment system.
