Terawet Green Technologies
"Uniting Science with Nature" 
San Diego, California, USA * Kolkata, West Bengal, India
Problems with Effluent
Rice mill effluent does not contain toxic compounds or pathogenic bacteria; but it can contain the traces of pesticide overdose, more so in the third world countries.
Discharge into soil or water bodies on a continuous basis causes major environmental problems.
The stagnant water emits off-odor. Off-odor during soaking can be generated due to fermentative changes.
The growth of natural flora is effected due to discharge of effluent into the soil. Since it is rich in nutrients it triggers the growth of algae in water bodies.
Further eutrophication leads to low dissolved oxygen content and poor water quality with high BOD.
Due to the color and turbidity of the wastewater, low penetration of sunlight into waterways affects photosynthesis processes of the residential flora.
In case of use of this water to irrigate rice fields this in turn destroys the beneficial algae and the microbial population that is either residential or dependent on those flora.
"The value of COD in parboiled paddy wastewater can range from 2578 mg/l to 6480 mg /l " (Subramanian and Dakshinamurthy, 1977 ).
But improvements in rice production technolgy and post harvest practice of paddy has improved the quality of effluent since then.
We found out that the COD range to be between 1800 mg/l to 5000 mg /l in the effluents from today's parboiling rice mills.
BOD range found in the effluent is from 400 ppm to as high as 1600 ppm in some cases.
Pollutant load in Puffed Rice Mill effluent is much lower due to the process itself and thus is much easier to treat.
Discharge into soil or water bodies on a continuous basis causes major environmental problems.
The stagnant water emits off-odor. Off-odor during soaking can be generated due to fermentative changes.
The growth of natural flora is effected due to discharge of effluent into the soil. Since it is rich in nutrients it triggers the growth of algae in water bodies.
Further eutrophication leads to low dissolved oxygen content and poor water quality with high BOD.
Due to the color and turbidity of the wastewater, low penetration of sunlight into waterways affects photosynthesis processes of the residential flora.
In case of use of this water to irrigate rice fields this in turn destroys the beneficial algae and the microbial population that is either residential or dependent on those flora.
"The value of COD in parboiled paddy wastewater can range from 2578 mg/l to 6480 mg /l " (Subramanian and Dakshinamurthy, 1977 ).
But improvements in rice production technolgy and post harvest practice of paddy has improved the quality of effluent since then.
We found out that the COD range to be between 1800 mg/l to 5000 mg /l in the effluents from today's parboiling rice mills.
BOD range found in the effluent is from 400 ppm to as high as 1600 ppm in some cases.
Pollutant load in Puffed Rice Mill effluent is much lower due to the process itself and thus is much easier to treat.
Typical effluent water analysis of Parboiling Rice Mill
Typical effluent water analysis of Puffed Rice Mill
| Parameters | Results |
| pH | 4.65 |
| Turbidity (NTU) | 145 |
| COD ( mg/l ) | 3800 |
| BOD ( mg / l ) | 890 |
Typical effluent water analysis of Puffed Rice Mill
| Parameters | Results |
| pH | 4.76 |
| Turbidity (NTU) | 65.7 |
| COD ( mg/l ) | 1080 |
| BOD ( mg / l ) | 357 |
