Case Study – Smaart Phytoremediation

Problem

A small resort of 40 rooms was having a hard time disposing their sewage from toilets, laundry and Kitchen.

Existing System

The existing system to dispose sewage consisted of two septic tanks.  In one of it, all the room toilets were collected.  In the second case, the kitchen waste was connected.

The over flow from the septic tank was let out in the neighboring fields.  The water created a smell and pollution nuisance.  The trees and grass in the neighboring plots were affected.

Smaart Water Intervention

Smaart Water understood the existing issues through a site visit.  SW estimated the size of the existing septic tanks, the discharge volume and got a water sample tested to check for the contaminants.  It subsequently estimated the size of the Phytoremediation Bed and showed a place to the client on the property where it can be kept and become a part of the landscape.

Scheme For Phytoremediation

Performance 

The performance of the system is summarized

The phytoremediation Bed shows a dramatic reduction in Nitrate, COD and BOD.  E.coli bacteria are absent.  The color and odor profile has substantially improved.

The pH is well buffered TDS has also 

The phyto plants were thriving dramatically

Key Points the Client Needed to Address

The poor condition, inadequate septic tank design and no cleaning of accumulated oil were the key issue at the client end.  SW advised the client to address the issues for a further better performance.  The poor condition lead to leaks and contamination of ground water.  The inadequate design resulted in oil slippage in to the phyto bed resulting in a bit of foaming and occasionally a bit of smell due to generation of sulphate reducing bacteria.  The slippage of oil also happened because the septic tank was hardly cleaned for the accumulated oil & grease.

Conclusion

Smaart Water helped its client install an energy efficient, all-natural sewage treatment system to treat hotel waste water comprising of Laundry, Toilet and Kitchen waste.  The treated water met the CPCB (Central Pollution Control Board) standard for category D water.

Growth of Phyto Plants

 

Solutions to the Smell and Foaming issues

Cause of Smell and Foam formation

Through technical discussions with Dr Tuhin Banerjee at NEERI, we have come to the conclusions

1. The smell and foam are related.
2. They arise out of the Kitchen Septic Tank.
3. They arise because of difficult to degrade organic material such as oil.

Solutions for Smell and Foam

1. Proper design and construction of Oil and Grease trap. (See schematic)
2. Periodic removal of oil and grease every few days
3. Avoid slippage of oil in all chambers through proper compartments and partitions.
4. Sealing of the Kitchen Septic tank so that it does not percolate into the environment

For short term solutions,

1. Keep Chlorine Tablet in the collection Tank.

TCCA 90% Tablet.

Spray mineral oil or rubbing alcohol (from chemist shop) on top of the foam using a spray bottle.

Conceptual Design of Kitchen Septic Tank

Total Volume 8000 lit

1. At least 3 chambers are required
2. Note the Pressure Balancing as all the chambers are connected at top
3. Note the Pipe lengths to prevent oil from getting into the chambers going forward
4. The tank has to be sealed.

If you need a detailed sketch, please ask us.

Chlorine Tablet Details

 

Available at Amazon

Hang two tablets in dispenser in the collection tank.  Near the falling water stream.

The tablet has limited solubility so it will last.