Sewage Treatment Plant (STP)

Working Principle

Sewage Treatment Plants operate on the principle of removing contaminants from wastewater through physical, chemical, and biological processes. The raw sewage first undergoes primary treatment (screening & sedimentation), followed by biological treatment (microbial degradation of organic matter), and finally tertiary treatment (filtration, disinfection, and polishing) to ensure safe discharge or reuse.

Technologies We Offer

✓ Activated Sludge Process (ASP)
✓ Moving Bed Biofilm Reactor (MBBR)
✓ Membrane Bio Reactor (MBR)
✓ Electro Coagulation System
✓ Sequential Batch Reactor (SBR)
✓ Rotating Biological Contactor (RBC)

Products & Components Used

✓ Screens, Grit Chambers, and Clarifiers
✓ Aeration Tanks and Diffused Aeration Systems
✓ Pumps, Blowers, and Agitators
✓ Membranes and Bio-carriers
✓ Disinfection Units (UV, Chlorination, Ozonation)
✓ Sludge Handling Equipment (Dryers, Thickeners, Centrifuges)
✓ Control Panels and Automation Systems

Applications

✔ Residential complexes & housing societies
✔ Hotels, resorts & hospitals
✔ Educational institutions & commercial buildings
✔ Industrial estates & factories
✔ Municipal corporations & urban projects
✔ IT parks & corporate campuses

Key Features & Benefits

✓ Advanced multi-stage treatment process for comprehensive wastewater purification.
✓ High-quality effluent suitable for discharge or safe reuse (gardening, flushing, cooling towers).
✓ Compact and modular design, adaptable to varying capacity requirements.
✓ Energy-efficient operation, minimizing environmental impact.
✓ User-friendly interface with remote monitoring and control capabilities.
✓ Compliance with stringent environmental regulations and CPCB norms.
✓ Robust construction for long-term reliability and low maintenance.
✓ Customizable solutions to meet specific project needs.

Operation Flow

Inlet → Screening → Primary Clarification → Aeration → Secondary Clarification → Filtration → Disinfection → Sludge Treatment → Outlet

Moving Bed Biofilm Reactor (MBBR)

Working Principle

MBBR is a biological wastewater treatment process that utilizes free-floating biofilm carriers made of high-density polyethylene (HDPE). These carriers provide a large surface area for microorganisms to attach and grow, creating a biofilm that breaks down organic matter and pollutants in the wastewater. The constant mixing in the aeration tank ensures optimal oxygen transfer and prevents clogging.

Technology & Process

Wastewater flows through an aeration tank containing thousands of biofilm carriers. Diffused aeration supplies oxygen while ensuring continuous movement of carriers. The biofilm absorbs organic pollutants, reducing Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and Total Suspended Solids (TSS). The treated water then passes to a clarifier for solid-liquid separation before final disinfection.

Design Variations

✔ Aerobic MBBR – Uses aeration for organic matter degradation.
✔ Anoxic MBBR – Removes nitrogen compounds through denitrification.
✔ Hybrid MBBR – Combines suspended and attached growth for higher efficiency.

Key Features & Benefits

✔ Compact design requiring 30–40% less space than conventional ASP.
✔ Handles high organic loading and shock loads effectively.
✔ No backwashing or frequent maintenance of media.
✔ Low sludge generation compared to conventional systems.
✔ Can be retrofitted into existing ASP tanks to enhance performance.
✔ Energy-efficient operation with high treatment stability.
✔ Media has a life span of 15+ years with minimal replacement needs.

Performance Standards

✔ BOD Removal Efficiency: 85–95%
✔ COD Removal Efficiency: 75–90%
✔ TSS Removal: 80–95%
✔ Effluent Quality: < 10 mg/L BOD (suitable for gardening, flushing, cooling towers)
✔ Designed as per CPCB/PCB discharge norms.

Applications

✔ Residential complexes and gated communities
✔ Hotels, resorts, and hospitals
✔ Food processing, breweries, and dairy industries
✔ Industrial effluent treatment (textiles, pharma, chemicals)
✔ Municipal sewage plants and decentralized STPs

Advantages over Conventional ASP

MBBR requires less land area, has higher treatment stability under load variations, and generates less sludge compared to Activated Sludge Process (ASP). It is also easier to expand or retrofit, making it ideal for upgrading existing plants.

Operation & Maintenance

MBBR systems are semi-automated and require minimal manpower. Routine O&M includes: blower inspection, DO monitoring, periodic sludge removal, and simple media checks. The modular design ensures easy maintenance without major downtime.

Example: MBBR tank with diffused aeration and HDPE biofilm carriers

Process Flow: Wastewater treatment using biofilm carriers in MBBR

Membrane Bio Reactor (MBR)

Working Principle

MBR combines biological treatment with membrane filtration, producing crystal-clear, pathogen-free water for reuse.

Technology & Process

Biological degradation occurs in aeration tanks, followed by membrane filtration that separates treated effluent from biomass.

Key Features & Benefits

✔ Produces high-quality effluent (near drinking standard)
✔ Compact footprint
✔ Consistent effluent under fluctuating loads
✔ Reduced sludge generation
✔ Easy automation and SCADA integration

Applications

High-rise buildings, IT parks, hospitals, hotels, industrial reuse.

Sequential Batch Reactor (SBR)

Working Principle

SBR treats wastewater in batches through fill, aeration, settling, decanting, and sludge removal stages in one tank.

Technology & Process

Automated cycles handle aeration, settling, and decanting, ensuring high efficiency and nutrient removal.

Key Features & Benefits

✔ Flexible operation for varying loads
✔ Excellent nutrient removal
✔ Automated cycle operation
✔ Compact footprint
✔ High-quality effluent for reuse

Applications

Municipalities, townships, food & beverage industries, industrial estates.

Activated Sludge Process (ASP)

Working Principle

ASP uses microorganisms in aeration tanks to metabolize pollutants. Oxygen is supplied to sustain microbial activity.

Technology & Process

Wastewater enters aeration tanks → aeration provides oxygen → microorganisms decompose organics → clarifiers separate effluent and sludge.

Key Features & Benefits

✔ Effective BOD & COD removal
✔ Flexible design for any capacity
✔ Stabilized sludge production
✔ Supports nutrient removal
✔ Complies with environmental standards

Applications

Municipal STPs, industrial effluents, residential and commercial projects.

Electro Coagulation (EC) System

Working Principle

Electro Coagulation (EC) treats wastewater by applying a direct electric current through sacrificial electrodes (usually aluminum or iron). The electric current causes the anode to release metal ions into the water, which neutralize the charges of suspended particles, colloids, and emulsified oils. These destabilized contaminants aggregate to form micro-flocs. Simultaneously, hydrogen bubbles generated at the cathode help lift these flocs to the surface, forming larger aggregates that can be easily removed by sedimentation, flotation, or filtration. This process reduces turbidity, color, and chemical oxygen demand (COD) effectively.

Key reactions include:

• Oxidation at the anode: Metal → Metal ions + electrons
• Reduction at the cathode: 2H2O + 2e⁻ → H2↑ + 2OH⁻
• Formation of metal hydroxide flocs: Metal ions + OH⁻ → Metal(OH)n (floc)

These flocs trap pollutants, heavy metals, oils, and dyes, which then settle or float for removal.

Technology & Process

Wastewater passes through EC reactors containing parallel plate electrodes. The electric field destabilizes colloidal particles, emulsified oils, and dissolved metals. Flocs form rapidly and either settle at the bottom or float to the surface aided by hydrogen bubbles. The clarified effluent is collected at the outlet while the compact sludge is removed periodically for disposal or further treatment.

Key Features & Benefits

✔ Removes heavy metals, oils & dyes
✔ Minimal chemical usage
✔ Generates compact sludge
✔ Eco-friendly & energy-efficient
✔ Easy retrofit & integration

Applications

Industrial effluents (textile, pharma, plating, food), oil & grease wastewater, municipal polishing, and wastewater containing colloids, dyes, or heavy metals.

Phytorid Technology

Working Principle

Phytorid is a nature-based wastewater treatment technology developed by NEERI (National Environmental Engineering Research Institute). It uses specially designed constructed wetlands with specific plants that treat sewage through natural processes like sedimentation, filtration, adsorption, and biodegradation. Microorganisms in the plant root zone enhance pollutant removal.

Technology & Process

Sewage passes through an engineered wetland bed filled with gravel, stones, and sand. Selected plant species (reeds, cattails, grasses) absorb nutrients while microorganisms degrade organic matter. The process combines physical, chemical, and biological treatment to produce high-quality effluent suitable for non-potable reuse.

Key Features & Benefits

✔ 100% natural, eco-friendly process
✔ Very low energy consumption
✔ Minimal O&M – no skilled manpower needed
✔ Aesthetic green landscape appearance
✔ No chemicals required
✔ Robust and long-term sustainable

Applications

✔ Residential colonies and housing societies
✔ Institutions (schools, colleges, hospitals)
✔ Small towns and decentralized sewage treatment
✔ Industrial wastewater polishing
✔ Parks, resorts, and eco-friendly projects

Performance Standards

✔ BOD Removal Efficiency: 85–90%
✔ COD Reduction: 75–85%
✔ TSS Removal: 85–90%
✔ Nutrient Removal (N & P): 60–70%
✔ Odor-free, clear effluent as per CPCB norms

Example: Constructed wetland bed with selected plant species

Process Flow: Phytorid system treating wastewater naturally