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STP Specifications: National Building Code 2005


I stay in a condominium where we have 644 flats (3/4/5 bedroom), would like to know how to calculate minimum STP requirement to support our condo as per National Building Code 2005. Currently we have 400KLD STP plant (however flats occupancy is 70% only) but for last few months it not not functioning properly and daily need to pump out the sewage.

a) No of Person per flats

b) Minimum litre per person sewage contribution . Some where it says 135 litre and some there 200 litre.





1. Dear Sandeep, NCB 2005 has

Dear Sandeep,

NCB 2005 has given a guideline for different population categories in the metro cities - and for metro cities (population more than 100,000) it is taken anything between 150 to 200 lpcd (NBC Part 9, In many Indian guidelines you can find a standard recommendation of 135 lpcd. In fact this figure is derived as follows: 

  • Bathing  55 washing of clothes 20 flushing of WC  30 washing of house 10 washing of utensils 10 cooking 5 drinking 5 Total 135

  • For an accommodation of HIG this amount can go up to 200 lpcd quite easily (per capita consumption in this range are obtained for metro cities in India). However, considering these figures (200 lpcd) 644 flats, each occupied by 5 persons (an average value), and 80% of supplied water is generated as sewage, the amount of sewage generated is 347 m3/d or kld. So your STP is adequately sized.

  • Considering the occupancy is 70% - you are receiving only 250 kld flow. There is no reason to believe that the plant is not operating properly due to overloading.

The problem must be in the STP itself. Get it checked by a good Consultant; he can help you with the problem

Best regards

 Sandeepan Chowdhury

2. Sewage and Effluent Treatment in cluster of Apartments

Dear Member,

You do not worry about all codes etc...At the start in design stage you would do all on standards and norms and regulations. As the time passes,as most people do not worry about O&M the problems starts to happen.

1. Ensure your STP is working fine, say the final effluent should be within 30-50ppm,

2. If is found higher always, than it is to be addressed, by having some add-on STP etc.

3. How big is your campus, 400 kl per day is 400,000 lits per day, this effluent water can irrigate all horticulture and peri-pheral greens etc.

Pl try to use the recycled water for flushing, garden-irrigation, and fire-fighting service etc..

We have done 6 projects on producing recyled water for varied uses in campuses etc..

Pl be in touch for details,


Er. Ajit Seshadri,Head- Environment, The Vigyan Vijay Foundation

3. Building Codes

Dear Sandeep,


Your problem can be easily solved; you will have to apply bio-remediation further to the treatment already being done.

Please review the practices given in the ppt here:Vigyan Vijay PPT and write to me in order to ensure further progress.

With well wishes,

Er. Ajit Seshadri
Secretary and Head- Environment & Energy
The Vigyan Vijay Foundation
New Delhi


4. Hi Sandeep -Regards.Giri

Hi Sandeep

I had, had a look into your note in this forum. May i understand , whether the problem is still on, and in case you would like to have a re-look, and come out of the problematic situation your STP is in, certainly i can provide my professional knowledge in overcoming the same.

I ve worked and provided my expertise in more than 200 plants all over India, and i continue to provide the same from Coimbatore. My mobile number is 9489348272 ,

Thank You



5. How to calculate actual cost per day of water?

We have calculated the water consumption per day from the municipal corporation but also receive water from borewell, then we can add both per day but how to add borewell water cost  so as to calculate the actual cost per day & additional expenses per day as per National Building code 2005

Ravi Tulankar

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