Offices And IT Buildings: Special STP Design For 100% Water Reuse

Offices And IT Buildings: Special STP Design For 100% Water Reuse

Offices And IT Buildings: Special STP Design For 100% Water Reuse

Office buildings such as IT companies employ people in thousands and there are even buildings that have more than 10,000 people working. Some of these offices work on 2/ 3 shifts basis, the information mostly know after a company has occupied the building. It would be prudent for a developer and builder of such a space to consider the worst case and plan for a sewage treatment system.


A building space for 1000 occupants when used in 3 shifts operates with 1000 during the day shift, 800 in the second shift, and 600 in the night shift. Some offices operate at 1000 employees in all 3 shifts. Now there is 3 times water load than the initially foreseen load theoretically. What should be a 50 KLD treatment plant now has a load of 100- 150 KLD, which makes treatment impossible in a 50 KLD plant. It is also a common practice for STP designers to consider a peak factor of 10 and only allocate 15 cm to the collection tank, which is filled within a few hours in the morning and is always overflowing.


EcoTec’s modular approach to STP design and operation has many benefits. In case the office has only single shift operations initially or permanently. There can be up to 4 modules in a single STP. Only one module can be put into operation as per wastewater generated. This saves a lot of energy and operating costs for the client. The other modules can wait till the inflow to the STP increases.


Moreover, there are pantries/kitchens in these office buildings. Indiscriminate dumping of cooked food and oil compromises the treatment plant's ability to handle solids in the wastewater water. Even sophisticated bar screens and oil separators have been compromised due to the indiscriminate dumping of food waste from kitchens/pantries.


EcoTec engages right from the planning stage with such property developers and helps them in planning for treatment systems that would give them the best cost and treatment quality benefit. Separating the kitchen wastewater and the rest of the wastewater means, easy treatment and effective reuse of the entire water needed for flushing and gardening is met with treated water.

80-90% of the wastewater generated from an office comes from activities such as hand washing, urination, defecation, and bathing. This water is easily treatable in a sewage treatment plant. Kitchen water adds to not more than 20% of total wastewater generation, but adds to 80- 150% of pollutant load in a sewage treatment plant and more often surpasses the design parameters considered.


Some companies have saved millions of liters of water and even more on energy costs by following our advice on,


1.      Separate the kitchen line and pantry line from the rest of the wastewater

2.      Treat kitchen water separately in a DAF and dispose of the sludge as solid waste

3.      The treated water from DAF can be further treated in STP for reuse

4.      Treat the rest of the less polluted wastewater can be treated in the EcoSBR process

5.      100% of this water is reusable for flushing

6.      Sludge generated from the DAF can be co-processed with the sludge generated from the STP and sent out as solid waste


The modular approach from EcoTec means that there is no reason for the plant to be put out of operation for any maintenance or cleaning operations of the STP. Hard to believe… You are most welcome to visit a plant that has been working for years consistently in a large company with more than 20,000 employees.