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Domestic Wastewater Treatment Process

Table of Contents

Understanding Domestic Wastewater: An Overview

Domestic Wastewater refers to the wastewater generated from the household through different Domestic activities e.g., laundry, dishwashing, garbage disposal and toilets. The domestic wastewater is usually divided into two main categories:

wastewater types Descriptions
Black Water Domestic wastewater comes in a combined form i.e. toilet, sink and dishwasher. It includes all the wastewater generated in the households.
Grey Water Domestic wastewater is generated from kitchens, sinks, wash basins, laundry washing, showers, baths etc.


The domestic wastewater pollution load is much less than that of industrial wastewater but the small number of Contaminants in domestic wastewater will harm the environment in terms of eutrophication & depletion of oxygen in waterbodies, Therefore the safe disposal of domestic wastewater is necessary for the protection of water bodies and environment.

The average pollution load of domestic wastewater varies as follows but this might be different depending upon the location and usage of water at home

Chemical Oxygen demand (COD)


Biological Oxygen demand (BOD)




350-500 150-250 <200 5-7

The selection of Domestic wastewater should be done by a complete analysis of wastewater and it should be remembered that there is nothing like one solution fit to all.

Importance of Domestic Wastewater Treatment for Environmental Health

The contaminant in the domestic wastewater may cause infectious diseases including diseases caused by bacteria and viruses, if the domestic wastewater is released untreated into the environment it may cause eutrophication of freshwater bodies due to the high content of nitrite and nitrate which is harmful to the aquatic life which causes the deficiency f oxygen in water bodies.

To make sure that our aquatic system and water bodies are safe from these harmful contaminants and waterbodies provide sufficient support to the aquatic environment, there are many types of domestic wastewater solutions available in the market for domestic wastewater treatment but BioTornado provides you with tailored and advanced technology which is CE certified and installed more than 4000 sites.


Components of Domestic Wastewater: What You Need to Know

Domestic wastewater has the following main components:

  • Collection system/Equalization tank: Collection of domestic wastewaters from different discharge sources into one collection tank.
  • Pretreatment system: This system uses prescreening and FOG removal technology to enhance the treatment in later stages.
  • Microbiological treatment system: These treatment systems may include anaerobic, anoxic or aerobic treatment Systems.
  • sedimentation/Sludge collection and Sterilization Tanks: the sedimentation tanks are used for the gravity separation of water and suspended solids and the sludge which is settled is collected in a sludge collection tank the water is further purified by dosing disinfectant in the Sterilization tank.
  • Control and operation system: the whole operation process of domestic wastewater is managed by integrated control panels, which adjust the whole operation according to the pollution load,

Any domestic wastewater treatment plant that has all of the above components does not mean that it is an effective domestic wastewater treatment system.

The design parameters, correct equipment installation, and standard operation of each technology will define the system’s treatment quality, based on each solution provider’s knowledge and experience.

In addition, the operation cost of the entire system to produce 1 m3 of clean water from wastewater is also an important criterion for evaluating the system quality.

The BioTornado technology and team have superiority in that case, the BioTornado uses 8 compartments for domestic wastewater treatment each with a camera to monitor the process efficiency of the process for excellent results. The team of BioTornado have decades of extensive experience in the industry of domestic wastewater treatment plants and they have installed and satisfied more than 4000 clients.


Primary Treatment process for Domestic Wastewater

The primary treatment of domestic wastewater comprises grit removal, large objects such as sticks, stones etc., which can damage the electromechanical equipment ahead.
The primary treatment removes 40-50% of suspended solids from the domestic wastewater after the domestic wastewater passes through the grit chamber it will enter into the primary clarification/sedimentation tank, where the gravity separation takes place between solid and liquid.

The primary solid/Sludge will enter into the sludge tank and the liquid from the primary treatment will enter into the Secondary stage for further treatment.


Secondary Treatment process for Domestic Wastewater

The secondary treatment of domestic wastewater treatment is the stage where the biological treatment i.e. aerobic, anaerobic or anoxic is applied to primary cleaned wastewater.

The secondary treatment process in domestic wastewater usually uses the activated sludge process and dissolved oxygen to promote the growth of microbes in the form of biological flocs that thrive on organic matter present in the domestic wastewater. the bacteria containing activated sludge is recirculated into an aeration tank to maintain and increase the decomposition of organic matter. The secondary process removes 90-95% of contaminants from domestic wastewater


Tertiary Treatment Processes for Domestic Wastewater

When the effluent from secondary treatment is unacceptable by EPA then the domestic wastewater enters into advanced treatment usually known as the tertiary treatment. the main purpose of this advanced treatment is to raise the quality of effluent before release into the environment or water bodies.

When domestic wastewater enters into the tertiary treatment system it contains a small amount of fine Suspended particles and harmful bacteria and viruses. The domestic water after passing through the tertiary can be reused, recycled and released into the water bodies.

The tertiary system uses advance technology i.e., activated sand filters, filter membranes and disinfectant to treat the domestic wastewater.

Factors Influencing Domestic Wastewater Treatment Efficiency

Several factors influence the efficiency of domestic wastewater treatment. These factors include:

Wastewater Characteristics: The composition and quality of wastewater, including the presence of organic matter, nutrients, pathogens, and toxic substances, significantly impact treatment efficiency. High concentrations of pollutants may require more advanced treatment processes.

Treatment Technology: The selection of appropriate treatment technologies based on the specific wastewater characteristics is crucial for achieving efficient treatment. Different technologies, such as activated sludge, biological filtration, and membrane bioreactors, offer varying degrees of efficiency for removing pollutants.

System Design and Configuration: Proper design and configuration of treatment systems, including reactor size, hydraulic retention time, aeration rate, and mixing intensity, are essential for optimizing treatment efficiency. Well-designed systems ensure sufficient contact time between wastewater and treatment processes, facilitating pollutant removal.

Operation and Maintenance: Regular operation and maintenance activities, such as sludge removal, equipment calibration, and monitoring of process parameters, are vital for maintaining treatment system performance. Neglecting maintenance can lead to system inefficiencies and reduced treatment effectiveness over time.

Environmental Conditions: Factors such as temperature, pH, oxygen availability, and sunlight exposure influence microbial activity and biochemical processes involved in wastewater treatment. Optimal environmental conditions support microbial growth and metabolic activity, enhancing treatment efficiency.

Influent Flow and Load Variations: Fluctuations in influent flow rate and pollutant load can affect treatment performance. Adequate provision for handling peak flow conditions and variations in pollutant concentrations ensures consistent treatment efficiency under different operating conditions.


Choosing the Right Domestic Wastewater Treatment System for Your Home

You are looking for domestic wastewater for your home and are uncertain which is an exceptional option for your home. while considering domestic wastewater make educated decisions and consider the following features before selecting any domestic wastewater for your home.

  1. Treatment Capacity of Domestic Wastewater Plant: The domestic wastewater treatment capacity is very important for the operation efficiency of operations, oversize or undersize domestic wastewater treatment plant doesn’t provide with desired effluent quality.
  2. Area covered by Domestic wastewater plant: The household has very limited space for the wastewater, so wastewater design should be compact like BioTorndao which can be installed underground without worry about the space.
  3. Technology and user-friendly: Domestic wastewater technology should be efficient, effective, and user-friendly, ensuring ease of operation and maintenance for homeowners.
  4. Maintaence requirement: Domestic wastewater treatment systems require regular interval maintenance to ensure optimal performance and longevity. Proper maintenance helps prevent system failures, prolongs equipment life, and maintains treatment efficiency.
  5. Enegy Consumption: The energy consumption of each domestic wastewater is different and before considering Domestic wastewater one should look for how much kWh is being consumed by domestic wastewater to produce 1m3 of clean water.
  6. Local regulation for effluent: The domestic wastewater is designed according to the local requirement, therefore before considering buying the domestic wastewater one should look into the legal EPA limit of their effluent.
  7. Cost of domestic wastewater treatment plant: The cost of a domestic wastewater treatment plant compasses various costs, including initial investment, maintenance expenses, energy costs, and potential regulatory compliance costs. So before deciding the domestic wastewater one should consider all these cost factors and make a wise decision.

BioTornado domestic wastewater treatment plant is one of the most reliable and trusted domestic wastewaters offer a wide range of treatment capacities ranging from 0.6 -7.5 m3/hr which means it can cater to 5 -50 person of households.

BioTornado works in all types of climates and its advanced treatment has 8 Chamber each equipped with a camera that can be installed underground effectively making the BioTornado a well-compacted solution for domestic wastewater customers, Moreover, BioTornado’s ability to blend with the aesthetic of surrounding making it the first choice for domestic wastewater customers.

Benefits of Effective Domestic Wastewater Treatment

The effective treatment of domestic wastewater plants enables the customer to use the treated wastewater for horticulture purposes, the reuse and recycling of wastewater will decrease the water footprint of the customer along with reducing the public health Risk.