Most distilleries in India have been generating huge quantity of high toxic effluents and in spite of the best effort made so far a comprehensive treatment has not been possible. Most of the treated effluent with the best available process technology also yields very high BOD, COD, SS, TDS levels with black colored and odors effluent to the streams, rivers and natural water. Due to this the environment suffers and gets damaged.

Based on the above mentioned fact, a treatment by which it will be possible to overcome all these problems have been worked out. The concept and treatment is based on the belief that all the BOD requirement is, in fact, due to the energy bearing organic materials allowed to go down he drain. If these energy bearing organic materials are trapped then this problem will not be there. A chemical by which all the organic mass is quickly precipitated, and water freed from all the BOD and COD have been developed. 

To Understand its advantages, it is important to understand the present treatment and the system generating effluents.

Generation of Effluents

As per practical experience, one tonne molasses having 46 Percent of fermentable sugar produces 240 litre(96.7% pure Alcohol) In the process, in each litre of Alcohol produced, around 15 litre of spent wash is produced, which has almost 45,000 to 55,000 mg BOD per litre and 1 to 1.5 lakh mg COD per litre.

A number of distilleries have gone for primary treatment of this spent wash by setting up a biomethanation plant where even the best possible results have given 85 % reduction in BOD. But in general, 65 to 70 reduction only have been achieved due to change in weather and other parameters.

Even with the best reduction in primary treatment, BOD load of 5,000 and COD load of 12,000 to 15,000 has been observed. But in most distilleries at normal functioning, BOD load of 10,000 to 12,000 and COD load of 30,000 to 35,000 has been observed.

The Chemical treatment system is designed to treat the BOD load of 12,000 and COD of 35,000

For reducing the above BOD, COD level to the MOEF/PCB standards through the conventional aeration system, huge capital investment and power is needed . This cost works out as shown in Table1

ET PROCESS

Table I:

Operating cost                 BOD      COD

(a) Effluent                       12,000     35,000
Effluent after treatment         100          250
Reduction required          11,900     34,750

Total oxygen demand       11,900  +34,750 = 46,650 mg/litre
                                                                   = 46.650 kg/ m3

For meeting out the above oxygen demand for oxydadon, normally 200% oxygen is required to be fed into the effluent. So the total oxygen input required per m3 = 93.30 kg m3

The best of the best conventional aeration system gives practically 1 kg to max 1.2 kg of O₂

Input for every KWH energy consumed. So the total energy required for the above = 93.30 KWH/m3

Cost of power Rs. 4.50 per KWH

Total cost of power 93.30 x 4.50 = 447.84

Or Say Rs. 450.00 per m3

(b) Manpower and chemical requirement, etc. Rs. 10.00 per m3

Cost of sludge disposal for incineration of 40 kg sludge / m3 Rs. 8.00 per m3

Total Rs. 18.00 per m3

(C) Fixed cost of treatment facility of about 500-m3/ day plant is Rs. 50 lakhs. Interest cost @ 18% on fixed capital Rs. 6.00 per m3

Repair cost and maintenance cost Rs. 6.00 per m3

Total Rs. 12.00 per m3

Grand total Rs. 480.00 per m3

The sludge generated in the process can be used as fuel in most of the cases. The total cost of the treatment plant is less than half of that of the conventional system and the cost of treatment also is substantially less than the conventional systems.

Effluent treatment chemical

An effluent treatment chemical developed by Lalit Kumar singhania is able to treat almost all types of difficult effluent like distillery paper plant parboilng plant, pharmaceutical plant, dye plant, black odorous effluent with high BOD, COD, TDS, SS to almost crystal clear transparent water, which can be even used for cooling purpose and on land for irrigation.
 

Major advantages

· Low cost of treatment 
· Low capital cost
· Lowland area requirement
· Total removal of BOD/ COD
· Total removal color
· Total removal of odour / bad smell
· Low power requirement
· Low manpower requirement
· Re use of water possible
· Use of sludge as fuel possible and 
· Faster treatment possible

Conclusion

It s concluded that the cost of conventional treatment definitely works out to be very high, as against treating the effluent by recovering the total BOD from the effluent and using this as an energy bearing material or fuel, which gives better economics than the present system, and the results are most effective.\

The cost of treatment through this technique works out as under:

1. Removal of BOD = Rs. 10 per Kg of BOD or minimum Rs. 120.00 per m3
2. Removal of COD = Rs. 2.5 per kg of COD or minimum Rs. 45 per m3
 

Total Rs. 165 per m3

The BOD arid COD levels are brought within the permissible limits of discharge, where 90 to 95 per cent color and odour of the water is removed.
 

For further detail cntact:

Lalit Kumar Singhania

Indus Technical and Financial Consultant Ltd.
Chatrubhuj kunj, 325 sarnta colony
Raipur, Madhya pradesh 492 001.
 

Source:Safety Health and Environment Bulletin
Date: April 6,2002