After reading this article you will learn about:- 1. Chemical Composition of Distillery Effluent 2. Standards of Distillery Effluents 3. Protocols for Utilization of Distillery Effluent for Irrigation of Agricultural Crops.
Chemical Composition of Distillery Effluent:
Distillery effluent which is generally known as spent wash is a dark coloured waste and has high BOD & COD values. Despite the high BOD & COD it has very good concentration of Inorganic minerals which are the basic requirement of most of the crops and can be reutilized.
ADVERTISEMENTS:
Colour — Dark Brown
Odour — Sweet
pH – 4.0-4.5
BOD – 40,000-50,000 mg/L.
COD- 90,000-1, 20,000 mg/L.
Total Solids-80,000-1, 00,000 mg/L.
ADVERTISEMENTS:
Suspended Solids — 30,000-40,000 mg/L.
Volatile Solids — 50,000-60,000 mg/L.
Total Nitrogen — 1,000-1,500 mg/L.
Rampur Distillery Rampur:
ADVERTISEMENTS:
Cycle of some important elements which is completed by Reutilization of Effluent for Irrigation.
Potassium — 8,000-15,000 mg/L.
Sodium — 1,000-1,200 mg/L.
ADVERTISEMENTS:
Calcium — 2,000-3,000 mg/L.
Magnesium — 2,000-3,000 mg/L.
Iron — 50-70 mg/L.
Phosphate — 800-1,000 mg/L.
Chloride — 5,000-6,000 mg/L.
Sulphate — 4,000-10,000 mg/L.
Production of spent wash is in the range of 12 Ltr-15 Ltr./Ltr. of Rectified Spirit. In Rampur Distillery it is 12.0-12.5 Ltr./Ltr. of Rectified Spirit.
Valuable Resources that can be recovered from distillery effluent are:
(1) Energy recoverable from organic matter.
(2) Organic matter as a liquid compost.
(3) Mineral and inorganic nutrients.
(4) Water.
1. Energy recoverable from Organic Matter:
Most of the distilleries have set up primary treatment plant where methane gas is generated by biological degradation of organic matter present in spent wash. There are several technologies available, but Rampur Distillery had adopted Aquatechnos Technology from Bangkok. In this technology effluent is treated at Thermophilic condition by thermophilic bacteria in a biogas reactor.
40 m3 Bio Gas/m3 of spent wash is generated.
a. Calorific Value of Biogas is 5,000-5,400 Kcal/m3
b. 1,000 m3 Biogas is equivalent to 1.6 MT. Rice husk.
Composition of Bio Gas is as:
Methane — 60-64%
CO2 — 34-38%
H2S — 2-3%
In Primary treatment only organic matter is converted to biogas, all inorganic mineral and nutrients remains as such. Amount of water also remains as such as there is no reduction in volume of effluent. Thus, it may be reutilized for irrigation. Inorganic mineral and water may be reutilized only by using this effluent for ferity irrigation purpose.
BOD & COD are still quite high after primary treatment, which are as under:
BOD — 6,000-7,000 mg/Lit.
COD — 40,000-48,000 mg/Lit.
Effluent with such a high BOD & COD cannot be used for irrigation. As per advise of Central Pollution Control Board and U.P. Pollution Control Board, secondary treatment plant is to be installed by each distillery. Most of the distilleries have set up secondary treatment plants. Rampur Distillery had also commissioned Secondary Treatment Plant in 1992. Technology was taken from Degromont India (p) Ltd.
Analysis of Final Discharge:
Colour — Pale Brown
pH — 7.5-8.5
BOD — 80-100 mg/L
COD — 2,000-3,000 mg/L
Total Solids — 1,300-2,000 mg/L
Total Nitrogen — 600-900 mg/L
Phosphate — 15-20 mg/L
Potassium — 700-1,500 mg/L
Magnesium — 50-80 mg/L Iron — 5-10
Sodium — 30-50 mg/L
Chloride — 50-80 mg/L
Before land preparation, in one irrigation, we can feed approx. 800 m effluent/hect of dry and it will meet almost 100% requirement of Nitrogen and Potash. However, some phosphate fertilizer may be required depending on the nature of soil.
For the use of effluent in fertiirrigation so many trials and experiments were conducted by Pant Nagar University, Indian Agricultural Research Institute and Hissar Agriculture University and other leading Agricultural Institutes in India.
Extract of these Research/Trials are as:
Pant Nagar University:
They conducted trials on several crops but we have considered the result of four major crops as under:
1. Maize:
Plant population and dry weight increased when irrigated in the treated effluent having up to 500 BOD. Up to 2, 00 mg/L. BOD level no mortality was observed.
2. Rapeseed:
No significant effect on plant height and dry weight upto 500 BOD level but seed yield increased. Seed yield was 21% extra. When irrigated with 500 mg/L. BOD effluent and additional N2 supplied @ 30 kg N2/hect are. At BOD level of 2,000 mg/L. mortality was 5% only.
3. Wheat:
Plant height was slightly more at 500 mg/L. BOD level but no effect on biological or grain yield at this BOD level.
4. Sugar Cane:
Dry weight increased significantly while no effect on plant height till 50’I mg/L. BOD level. In fact the growth kept on increasing with increased BOD level and at 3,000 BOD level both plant height and dry weight nearly doubled.
From all it is clear that there is no harm to any crop up to BOD level 500 mg/L. However. Sugar Cane crop can be irrigated with effluent of 3,000 BOD level and rape seed can be irrigated without any harm up to BOD level of 1000 mg/L.
Professor P. Keshava Rao of Nagarjun University quoted that yield of Paddy also doubled with distillery effluent.
Finding of some institutes and group of scientists regarding use of effluent for irrigation purpose are as:
1. Brazil, Cuba and other South American Countries have been using untreated effluent for ferti irrigation for the last more than two decades with no deleterious effects to the soil or environment.
2. A Dutch fact finding Mission invited by Govt., of India in 1986 for solving problems of Distillery effluent, had supported the above said view point of the Industry.
3. Prof. P. Taru of Haryana Agricultural University has recommended utilisation of pre-treated distillery effluent for ferti-irrigation.
4. The views of Dr. Taru have been supported by Twelve Universities/Institutes.
5. Dr. W. Verstracteo GENT Agriculture University, Belgium has also supported with the view-points of Dr. Taru and concluded that this is an excellent fertilizer containing humus and minerals.
6. Prof. P. Keshava Rao of Nagarjun University has observed in his treatise that the microbes in the distillery effluent if recycled to land, could transform even fallow lands into fertile ones.
7. Indian Agriculture Research Institute concluded that “Distillery Effluent’s can help in reducing fertiliser use drastically as they are a rich source of major nutrients needed for optimal plant growth”. Treatment with 20% effluent can help in replacing potassium use totally and Nitrogen, phosphorus use by half (may save Rs. 150 Crores).
The mission suggests not to impose a scheme of secondary aerobic treatment that would lower the BOD contents of the treated waste streams to the required level without dilution. Such a scheme would result in disproportionately high cost and would lead to unnecessary destruction of valuable organic material.
Dr. Tauro Professor of Eminence, Haryana Agriculture University who has published a treatise on distillery effluent, has arrived at the conclusion that it will be against national interest to subject distillery effluent to secondary treatment. A large number of Scientists and microbiological experts from a number of universities and institutes, all over the Country and abroad, agreed with the findings of Dr. Taru.
(1) The use of treated distillery effluent is not harmful to crops particularly sugar cane and on the other hand, produces nutrient organic matter and water.
(2) Application of the treated distillery effluent which is in fact a liquid compost is the best way of returning to the soil, what the plant had withdrawn.
(3) Application of the treated effluent up to three times in a cropping season needs small area and would be quite safe.
(4) The odour of the effluent (treated) is similar to that of the farm yard which is extensively used in crop cultivation.
(5) Irrigation of crops such as sugar cane with distillery effluent is much safer than irrigation with city sewage.
(6) Irrigation with treated distillery effluent will save both irrigation water and fertilizer. Experience from Brazil Indicates that the application of even primary treated effluent creates an organic fertilization which can improve the quality of soil, increase availability of certain nutrients capability to retain water and even improves physical structure.
Such methods are being used in Brazil for many decades. There has not been detected any adverse effect so far on the use of above mentioned methods on the soil. So, there should be no hesitation if distillery effluents are utilized for fertiirrigation of land.
Standards of Distillery Effluent:
1. 30 PPM FOR DISCHARGE ON WATER.
2. 100 PPM FOR DISCHARGE ON LAND.
In 1993, Ministry of Environment issued a directive vide circular dated 12. 01. 93 that distillery could utilize their effluent for fertiirrigation after treating the same through bio methanation plants. For that purpose BOD limit was set 500 and 700 mg/L.
In this regard environment protection rules were amended accordingly and distillery effluent with BOD load of 500-700 mg/L. were permitted to be disposed of on land. This provision in the rules has remain in force till 2.4. 96.
The sudden stoppage of utilization of effluent for fertiirrigation of land created enormous problems for the distillery. In Feb’ 98, C.P.C.B. directed a protocol defining the basic requirement to use effluent in fertiirrigation.
Protocols for Utilization of Distillery Effluent for Irrigation of Agricultural Crops:
Based on the field and experimental studies carried out by the Indian Agricultural Research Institute (IARI), Delhi and the experience of the Central Pollution Control Board in application of industrial effluents on land using it as a treatment medium, the following protocols are recommended for the utilization of treated distillery effluent (BOD 500 mg/L) for irrigation of agricultural crops.
(a) Basic Requirements:
(1) Any distillery desirous of utilizing the effluent for irrigation should have completed the construction and commissioning of bio-methanation plant for primary treatment of spent wash followed by secodary biological treatment (aerobic), before utilization on land for irrigation.
(2) The distillery shall construct pucca and lined storage tanks with a minimum retention time of 3 months for storing the spent wash during the monsoon and/or non-irrigation period.
(3) The command area requirement for irrigation shall be calculated at the rate of not less than 9 ha/kilo litre of daily alcohol production capacity of the distillery. For example, a distillery of 30 kid installed alcohol production capacity will require minimum 270 ha of land for irrigation under the scheme.
(4) The distillery shall construct distribution channel network for transporting effluent preferable of closed conducts or of pucca construction, to cover the area irrigated under the Scheme
(5) The distillery after fulfilling the above basic requirements shall prepare a comprehensive “Irrigation Management Plan” (IMP) for utilisation of its effluent and get it approved by the State Pollution Control Board at the time of grant of consent. The IMP include the details on,
(i) Survey/plot (khasra) numbers of land for irrigation under the scheme along-with their area,
(ii) Written agreement with the owners (farmers) of the land mentioned in (i) above, to bring their land for use under the scheme.
(iii) Source or arrangement for irrigation water required for the preparation of effluent so as to achieve the characteristics as follows before releasing the effluent for irrigation.
(iv) The depth of one irrigation shall not be more than 10 cm or as per the crop requirement, whichever is less. The total number of irrigations shall not exceed six for any crop.
(v) Agronomic plan for effective utilization of land by crop rotation,
(vi) Effluent distribution schedule to the fields,
(vii) Infrastructure a facilities available/planned for collection and analysis of samples collected as per Part (C) of the protocol, and
(viii) Full time expert and other manpower employed for the purpose of managing the IMP.
(b) Safety Protocol:
(7) Though, the crops normally cultivated in the area can be grown under the scheme, the
rotation of wheat, rice and sugarcane crops is preferable.
(8) Effluent application during the germination and seedling growth shall be avoided
(9) Any concurrent use of fertilizers and pesticides shall be done judiciously to avoid superimposed effect.
(c) Monitoring Protocol:
(10) The physiochemical characteristics of the soil under irrigation by distillery effluent shall be regularly monitored for pH and Electrical Conductivity (EC). On representative sample per 10 ha at depth of 30 cm and 60 cm, shall be collected at least twice a year, for this purpose. The pH and EC of the extract of the mixture of 2 parts of soil with 5 parts of water shall not exceed 8.5 and 4 millimhos/cm, respectively.
(11) The groundwater quality shall be monitored by installing one hand pump for covering 20 ha area and one bore well for 10 ha area of land. Groundwater samples shall be collected at least once in a month and monitored for BOD shall not exceed 3 mg/L, (i) Nitrates, expressed as ‘N’ shall not exceed mg/L, and (ii) TDS shall not exceed by 10% or 200 mg/L. whichever is less.
(12) The records of soil and groundwater quality monitoring data so collected shall be properly maintained for verification by the State Pollution Control Board. The soil and groundwater quality shall be monitored by the State Board, at least once after every cropping season, for cross-verification.
(13) In the event of first observation of any of the soil and groundwater monitoring parameters, exceeding the prescribed limits, effluent application shall be stopped immediately and the distillery shall communicate the matter to the State Board about such observation. The industry would be solely responsible for reclamation of soil and groundwater quality at their own cost and expense, in case of damage.