Household wastewater, also known as domestic sewage, originates from kitchens, bathrooms, toilets, and laundry areas. It contains a mix of organic matter, food scraps, soap residues, detergents, oils, and human waste. If released untreated, this wastewater can cause severe environmental pollution, including contamination of water bodies, soil degradation, and public health hazards.
This is where a Sewage Treatment Plant (STP) plays a crucial role. STPs are engineered systems designed to clean household wastewater and make it safe for discharge or reuse. In India and around the world, 3D AQUA stands out as a trusted name in the manufacturing of robust, scalable, and efficient sewage treatment solutions for both residential complexes and communities.
In this article, we explore each stage of the household wastewater treatment process in detail, explain how it works, and show how 3D AQUA’s advanced STP systems address every step with precision and reliability.
Understanding Household Wastewater
Domestic wastewater typically contains:
- Blackwater: From toilets (rich in organic matter and pathogens)
- Greywater: From sinks, showers, and washing machines (contains detergents, oils, and small particles)
The treatment process must handle both these types of waste and ensure that the output water complies with local pollution control norms.
Stage 1: Preliminary Treatment
Goal: Remove large, non-biodegradable materials that could damage equipment or obstruct flow in later stages.
1. Screening
The first defense line in an STP is the screening system. Bar screens or mesh filters trap large solids such as:
- Rags
- Plastics
- Sanitary items
- Food wrappers
At 3D AQUA, we install automated mechanical screens in larger plants to reduce manual labor and improve operational efficiency.
2. Grit Removal
Grit such as sand, gravel, broken glass, and eggshells enter household wastewater through kitchen drains and wash areas. These are dense materials that settle quickly.
We use vortex grit chambers or aerated grit tanks, where the flow of water slows down, allowing the grit to sink to the bottom. Removing grit is essential to avoid abrasion and reduce wear on pumps and valves.
Stage 2: Primary Treatment
Goal: Separate suspended solids and reduce organic load before biological treatment.
1. Primary Sedimentation Tanks
Large sedimentation basins allow wastewater to remain undisturbed. In this calm environment:
- Heavier particles sink to the bottom (forming primary sludge)
- Fats, oils, and grease float to the top (forming scum)
Mechanical scrapers continuously collect the settled sludge while surface skimmers remove the scum.
3D AQUA designs rectangular or circular primary clarifiers with adjustable retention time to suit the size of the household or colony.
2. Sludge Removal
The collected sludge is pumped into sludge holding tanks. It’s important to treat this sludge separately to prevent odor, vector issues, and environmental harm.
Stage 3: Secondary (Biological) Treatment
Goal: Use microorganisms to break down dissolved organic pollutants.
This stage mimics natural processes but accelerates them under controlled conditions.
1. Aeration Basins
In aeration tanks, air is introduced through diffused or mechanical aerators. This oxygen supports the growth of aerobic bacteria that consume organic waste.
3D AQUA’s systems often use:
These modern biological technologies improve efficiency and reduce footprint while handling varying loads.
2. Biomass Formation
As bacteria feed, they form flocs—clusters that include organic waste, bacteria, and other particulates.
The resulting mixture, called mixed liquor, is transferred to the next phase.
3. Secondary Clarifier
In the clarifier, the microbial flocs settle, forming activated sludge. The clear water, or treated effluent, rises to the top and is sent to the next stage.
A portion of this settled sludge, known as Return Activated Sludge (RAS), is pumped back to the aeration tank to maintain microbial population. The excess sludge (WAS) is sent for further treatment.
Stage 4: Tertiary Treatment
Goal: Further polish the effluent to remove nutrients, pathogens, and fine particles before reuse or discharge.
1. Filtration Systems
Water passes through media filters, which can include:
- Sand
- Activated carbon
- Anthracite
This removes remaining suspended solids, color, and odors.
3D AQUA offers automated backwash filters that regenerate without manual effort.
2. Nutrient Removal (Optional)
In cases where the effluent contains excess nitrogen or phosphorus (from detergents, soaps, or urine), nutrient removal becomes necessary to prevent eutrophication of natural water bodies.
Our advanced STPs integrate Biological Nutrient Removal (BNR) or chemical dosing systems to address this.
3. Disinfection
Disinfection ensures no pathogens survive before the water is released. Popular methods include:
- Chlorination: Affordable and reliable but requires dechlorination.
- Ultraviolet (UV) Disinfection: Environmentally friendly and fast.
- Ozonation: Powerful but costlier, suitable for sensitive applications.
3D AQUA recommends the best method based on application—reuse in toilets, landscaping, cooling towers, or discharge to stormwater drains.
Stage 5: Sludge Treatment and Disposal
Sludge removed during earlier stages contains high moisture and must be treated further.
1. Thickening
Gravity thickeners concentrate the sludge by removing free water, making it easier to handle.
2. Dewatering
Using:
- Filter Presses
- Belt Filter Presses
- Centrifuges
These systems reduce the water content, turning sludge into semi-solid “sludge cakes.”
3. Disposal or Reuse
- Landfilling: If treated safely.
- Composting: To make soil conditioners.
- Incineration: In cases of toxic sludge.
3D AQUA helps clients comply with CPCB guidelines and municipal solid waste norms for sludge disposal.
Optional Add-ons for Household STPs
To enhance efficiency and sustainability, 3D AQUA also offers:
- Remote Monitoring Systems (SCADA)
- Solar-powered STP units
- Odour control units
- Containerized and Packaged STPs for homes, resorts, and townships
These modern features reduce manual supervision and lower carbon footprint.
Reuse of Treated Water
Treated household wastewater can be reused for:
- Flushing toilets
- Irrigating gardens and landscapes
- Washing vehicles
- Cooling tower makeup water
This not only conserves freshwater but also reduces the load on groundwater and municipal supply.
3D AQUA designs STPs keeping water reuse in mind, helping clients become water-positive.
Why Choose 3D AQUA for Household STPs?
- ✅ Over a decade of expertise in water and wastewater treatment
- ✅ Custom-built STPs from 1 KLD to 1000 KLD for homes, societies, and townships
- ✅ Advanced MBBR, SBR, and MBR technologies
- ✅ Compliance with CPCB, NGT, and municipal discharge norms
- ✅ End-to-end service from design to installation and O&M support
Our systems are engineered to be low-maintenance, space-saving, and energy-efficient—making them ideal for both rural homes and urban complexes.
Conclusion
A Sewage Treatment Plant (STP) is essential for managing household wastewater responsibly. It transforms harmful sewage into clean, reusable water through a series of physical, biological, and chemical processes. With water scarcity and pollution becoming major issues, installing an efficient STP is no longer optional—it’s a necessity.
3D AQUA stands as a pioneer in the domestic sewage treatment space, offering smart, sustainable, and compliant solutions. Whether you’re a builder, resident welfare association, or an individual homeowner, we have the right STP to match your needs.
Ready to upgrade your home or society with a reliable wastewater treatment solution?
Reach out to the experts at 3D AQUA today.
📞 Phone: +91-6262629090
📧 Email: info@3daqua.in
🌐 Website: www.3daqua.in