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Water and Wastewater Consulting

  • Let us understand first What is waste water: Water which is used to fulfill various purposes and day to day operations. Waste water may be sewage, stormwater and waste water from the industries. Wastewater is generated from two types of sources Residential and Nonresidential which is also called Industrial waste water or may be called effluent. If the wastewater is discharged without the proper treatment it can be dangerous to both human and plant life.We can classify the waste water into two types as following:

Sewage Treatment Plant: Domestic waste water

As the name suggests, domestic wastewater is the toilet, bathroom and kitchen waste that every household generates on a daily basis. Generally, domestic wastewater can be generated from residential apartments, commercial buildings, hotels, and public offices.
  • Domestic sewage can be divided into following: categories:
  1. Black water: It the wastewater that is generated from the toilets and bathroom.
  2. Grey water: It is the wastewater generated from the kitchen, washing machine, bathtub etc.
  • Both types of domestic waste water have different characteristics but have pathogens and disease-causing bacteria. Black water has the fecal coliform bacteria. Biological treatment followed by disinfection is required to treat the domestic water.
  • Treated waste water can be reused and recycled back into the system for flushing and irrigation purposes to reduce the fresh water demand.
  • There are 4 types of Sewage Treatment (STP) technologies available 
  • MBBR (Moving bed biofilm reactor)
    SBR (Sequencing Batch Reactor)

    ASP (Activated sludge process)


  • Moving Bed Bio Reactor (MBBR) a process based on the biofilm that helps to develop the microorganism and bacteria to grow on it.
  • The media on which the bacteria grows floats on the aeration tank through the help of air diffusers placed at the tank bottom 
  • The organic matter present in the waste water by means of biological oxygen demand is transformed into new cells, Co2, energy and water.
  • The wastewater next flows to the sedimentation tank for the settlement of sludge to the bottom of tank
  • Activated sludge which is rich cultured organism produced during the secondary clarifier process returned to the aeration tank 
  • Clear water from the clarifier overflows further for the disinfection of water
Moving Bed Bio Reactor Process Flow Diagram

Activated Sludge Process (ASP) Technology

  • Activated sludge process has the screening chamber followed by the grit removal chamber.
  • The water flows to the primary clarifier tank where the suspended solid particles get sedimented at the bottom of the tank and the collected sludge transfer to the sludge thickener tank.
  • The aeration tank is fed into the water coming from the primary clarifier where the microorganisms transform the organic matter present in the waste water into suspended particles, energy, carbon di-oxide and water. 
  • Secondary clarifier system separates the clear water and activated sludge remaining at the bottom that is transferred further to the sludge thickener tank.  
  • Some part of the activated sludge is transferred back to the aeration tank.
  • Clear water coming out of the secondary clarifier tank goes through the disinfection process by means of chlorination or Ultra-violet system to kill the pathogenic bacteria.
Activated Sludge Process (ASP) Process Flow Diagram

ETP (Effluent Treatment Plant)

  • ETP (Effluent Treatment Plant) is a process design system to treat the industrial wastewater by means of physico-chemical reaction for the reuse and recycle and safe discharge to the environment.  
  • There is a key difference between influent and effluent, influent means untreated water and effluent means treated water. 

Why ETP (Effluent Treatment Plant)

  • To reduce the fresh water requirement in day to day activities and operations 
  • To treat the influent from the industrial operations and reuse and recycle it
  • To cut the water cess 
  • To keep the waste water discharge standards under the permissible limits defined by CPCB and to avoid penalties by the Pollution control board and National Green Tribunal 
  • To play an important role by the industries towards the sustainable development

Treatment types of ETP

  • Preliminary  
  • Primary  
  • Secondary  
  • Tertiary
  • Preliminary Treatment: It separates the large objects like cloth, wood, plastics and other visible things from the wastewater. These include screening, sedimentation and clarification.

  • Primary Treatment: Removal of floating, suspended particles and organic materials by means of physical and chemical treatment
      • Ph has to be balanced by mixing acidic and alkaline substances in the waste water
      • Coagulation and flocculation by adding the alum to the waste water
  • Secondary Treatment: It means biological and chemical treatment 
      • Bacterial is fed into the process to transform the organic and inorganic matter into suspended solid, energy and water 
      • Aerobic treatment takes place in the presence of air and anaerobic treatment takes place in the absence of air 
      • Methane and suspended solids are formed during the anaerobic treatment
  • Tertiary Treatment: Removes the residual organic and inorganic substances, it also removes the bacteria, virus, and other pathogenic microorganism present in the water.
      • Chlorination 
      • Activated Carbon Filter 
      • Multigrade Filter
Typical Process Flow diagram of an Effluent treatment plant

Annual Maintenance and Contractual Services (AMC of STP/ETP)

  • Why AMC STP/ETP services: In an Industrial set up or any infrastructural projects, A STP or ETP gets through a lot of challenges when it comes to operating the plant effectively and smoothly without any major breakdown. 
      • There are different physical, chemical and biological processes involved to treat the water once the raw waste comes through the plant. 
      • Industries can have the best sewage or effluent treatment technology installed, performance may be all star but in the absence of regular check ups and periodic maintenance, it is not possible to have the expected quality results as far as outlet water quality parameters are concerned.
      • Operation and maintenance of STP/ETP considers to keeps overall checks and balances, to have the optimum water quality results without physical, chemical and biological breakdown or failure of the plant

STP/ETP Operation and maintenance considerations:

  • Sludge Removal & General Housekeeping
  • General Day to day planned maintenance and preventive maintenance
  • Check abnormality in the pump and motors and if found, fixing of it 
  • Chemical preparation and dosing
  • Oiling and greasing of Pump and motors 
  • Ensure the water quality standards are under permissible limits 
  • Ensure overall plant runs smoothly and efficiently 
  • Inlet/outlet wastewater collection and sampling 
  • Proper operation of all equipment
  • Check, test and ensure water quality results are under desired limits of CPCB
  • Follow the PDCA cycle (Plan, Do, Check, Act)

contact us

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say Hello to Northern Ridge

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Step 3

timeline and budget planing

Step 4

Task assignment to team member

Step 5

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