Sewage Treatment Plants


STP is a facility to treat waste water collected from the households, colonies, townships or cities. Wastewater contains contaminants that include bacteria, organic chemicals and other toxins. STP aims at reducing these contaminants to the acceptable level. Micro-organisms converts the polluted water, sewage, waste etc. into the clean or clear water. STP improves the quality of water and makes it safe for disposal or discharge back into the environment or the treated water can also be reused for the purpose of gardening, irrigation, flushing etc. depending on the degree of treatments involved.

This process also produces co-product like compact solid biomass, methane, nitrogen etc. However, translating this simple principle into a properly designed and engineered STP is a real challenge.

Importance of STP

Looking at the growing concerns for the environment and water scarcity issues, effective treatment of sewage using sewage treatment plants has become a very crucial requirement. A well designed STP is the best solution to address the issues related to the environment by treating the waste water effectively. Presently, large size STP’s are designed and constructed in conventional ways, but till date, for small size requirements, there is no reliable or user friendly solution available. Considering this need for effective and user-friendly solution and to address various problems in the conventional methods, Supreme has come out with a superior, ready to use, packaged STP’s under the brand name of Safegard.

Safegard Packaged STP’s are Designed to

  • Achieve the desired results on a consistent and sustained basis
  • Lasts for at least 10-15 years without major maintenance or repairs
  • Achieve the desired treated water quality in minimum cost, energy and chemicals
  • Facilitate user- friendly installation
  • Easy operation and maintenance

Components of Safegard Packaged STP

  • Bar screen
  • Grit settler
  • Equalizing tank
  • Anaerobic reactor
  • Aerobic reactor
  • Settling tank
  • Sand filter
  • Activated carbon filter
  • Disinfection unit
  • Automation unit
  • Wetland (Optional)

Unique Features

  • Intelligent combination of anaerobic and aerobic treatment
  • Excellent effluent quality – Meets SPCB/CPCB requirements
  • Excellent treatment efficiency and energy efficient
  • Hygienic and safe operation
  • Free from leakages, breakages and blockages
  • No root penetration and fungal growth
  • Rust proof
  • Minimal sludge generation
  • 70% reduction in O & M cost compared to conventional STP’s
  • Compact space saving design
  • Fully autonomous – no need of skilled supervision
  • Minimum intervention with self-sustainability
  • Availability with a design option for underground or above the ground installation or its
  • Available from 5 to 100 KLD capacities
  • No chemical dosing
  • Simple, quick and user friendly installation
  • Aesthetic view and noise free working
  • PLC based automatic operation

Product Range

We offer packaged sewage treatment plants in different sizes ranging from 1 KLD to 30 KLD capacities as given below

Sr. No.ModelCapacity (KLD)
1SPSTP-51 to 5
2SPSTP-106 to 10
3SPSTP-1511 to 15
4SPSTP-2016 to 20
5SPSTP-2521 to 25
6SPSTP-3026 to 30

Note: For STP’s over 30 KLD capacities the designs will be provided based on project specific requirements.


  • Residential and Commercial Complexes
  • Public Gardens and National Parks
  • Hotels and Resorts
  • Restaurants
  • Industries (domestic waste water)
  • Institutions
  • Hospitals
  • Temples
  • Government Offices
  • Labour Quarters
  • Townships

Working Mechanism

1. Primary Treatment

Bar Screen and Grit Settler: The function of the bar screen is to prevent entry of floating particles such as plastic cups, paper dishes, polythene bags, condoms and sanitary napkins into the STP. If these items are allowed to enter the STP, they clog and damage the STP pumps, and could cause malfunctioning of the plant. The screening is achieved by placing a screen made out of vertical bars, placed across the sewage flow. Typically this is the preliminary level of filtration.

Equalization Tank: The sewage from the bar screen chamber reaches to the equalization tank. This tank is the first collection tank in an STP. Its main function is to collect the incoming raw sewage that comes at widely fluctuating flow rates and quality. During the peak hours, sewage comes at a high rate. The equalization tank stores this sewage, and let it out during the non-peak time when there is no or little incoming sewage.

2. Secondary Treatment

Anaerobic digestion: Anaerobic process is the process through which microorganisms break down the biodegradable material in the absence of oxygen. This is used for the treatment of domestic or industrial waste. This process is mainly used to reduce the energy in waste treatment and sometimes to gain energy also.

Aeration: The aeration tank is at the heart of the treatment system. The main function of the aeration tank is to maintain a high population level of microbes. This leads to better degradation in a given time span or minimizes the required reactor volumes. In comparison to the conventional activated sludge process (ASP) which typically achieves 95% overall efficiency, in Safegard STP it reaches up to 98%.

3. Tertiary Treatment

For giving self-sustainable tertiary treatment for the treated wastewater, it is proposed to construct a wetland or polishing by a sand filter and activated carbon filter. Treated water is then subjected to disinfection by Ozone or Chlorine (Sodium Hypo Chloride)

Schematics of Sewage Treatment Plant

Capacity Selection Chart

Type of Project Model
KLD 5 10 15 20 25 30 40 50 60 70 80 90 100
(135 LPCD)
No. of Users   37   74   111   148   185   222   296   370   444   519   593   667   741
Hotel with laundry
(370 ltrs per room)
14 27 41 54 68 81 108 135 162 189 216 243 270
Hospital with laundry
(450 ltrs per bed)
11 22 33 44 56 67 89 111 133 156 178 200 222
Office & Educational Building
(45 LPCD)
111 222 333 444 556 667 889 1111 1333 1556 1778 2000 2222

Benefits of Safegard Packaged STP’s vs Conventional STP’s

Safegard Packaged STP

Conventional STP

Consistent efficiency throughout the year

Seasonal variations are observed

Sludge handling required once in 1-2 years

Sludge handling once in 15 days

Skilled supervision not required

Continuous skilled monitoring required

More than 70% electrical saving compared to conventional STP’s

It consumes higher electricity than Safegard STP

Aesthetic appearance

There is a nuisance of foul smell and flies

Leak proof, no root penetration and no fungal growth

Prone to leakages, root penetration and fungal growth

Life of modular tank is more than 50 years

Life less than 20 years

Technical Support

Being a fully technical product, necessary support in designing and installation will be made available.