Using Distillery Spent Wash For Ferti Irrigation
By Dr. Yashpal Singh
For other topics related to the Distillery Sector and a review based on more than 350 publications covering Indian Distillery Industry, Manufacturing Process, Composition of Effluents, Environmental Impacts, Treatment Technologies, Utilization of Spent Wash In Agriculture, Impact On Soil, Crops And Yield, Pre-Sown Land Application, Ferti-Irrigation, Bio Composting, Soil Reclamation, International Practices in The Utilization of Spent Wash in Agriculture, Major Provisions of The Environment, Forest and Pollution Control Laws in India, Environmental Performance Rating, Major Policy Interventions and The Views Of The Honorable NGT On Sustainable Technology Adoption see Singh Yashpal 2020, Distillery Spent Wash and Its Utilization in Agriculture. Publisher – The Wealthy Waste School India. ISBN No. 978-93-5396-249-4. Pages 1 to 360 (Available at Amazon and Kindle Books)
Fertigation is an emerging field for agricultural purposes because it applies water and fertilizer simultaneously and use of distillery water in fertigation could lead to proper management of waste water and conservation of ground water. The manure potential of distillery effluents can profitably be used as a supplement to fertilizer along with irrigation water. Most of the authors are of the opinion that spent wash at lower concentrations can be safely used for irrigation and fertilization. Because of a very high concentration of K, the distillery effluents have to be supplemented with other nutrients, notably N, P and S to give it a balanced nutritional value. Some authors have observed that delaying the application of urea supplemented spent wash until the crop has grown to 0.5 meters in height produced the best results. Direct application of post methanated spent wash to growing crops is discouraged because of the excessive BOD, COD and EC. Sugar mill effluents may be used as a suitable diluent for spent wash to reduce the pollution load and subsequently used in fertigation with a 1:1 dilution ratio, the BOD has been expected to come down to 3600 mg/L from 51023 mg/L, COD to 62075 MG/L from 90179 mg/L and TDS to 32700 mg/L from 72090 mg/L.
Diluted spent wash irrigation has been tried without any adverse affect on soil fertility, seed germination and crop productivity. The physical and chemical properties of the soil have improved and so has the soil micro flora. The CPCB has held that emerging technologies such as ferti-irrigation should be opted by the industries for secondary treatment of wastes and has added that this may not only control pollution at source but also act as an alternative for energy savings for treatment of distillery waste water. It is important that ferti-irrigation and irrigation be differentiated in terms of utility to crops and separate procedures for ferti-irrigation and irrigation evolved. Applying the existing standards of 100 mg/L ( on land for irrigation) to ferti irrigation would need reconsideration.
Grasses, barley, wheat, sugarcane, maize, sorghum pulses, gram, pea, paddy, ground nut, flowering plants, vegetables, beans, have all responded positively to various dilutions of spent wash irrigation and registered significant increase in the yield parameters. Distillery waste water irrigation has been observed to have significantly increased the nutrients in the soil. The agronomical performance (V. Mungo) was found to have been significantly increased at lower concentrations (20 to 40%) decreasing as the concentration increases (60 to 100%)
Application of lower doses of digested spent wash to the soil, either along with irrigation or as a soil amendment has a beneficial effect on soil nutrients and their uptake resulting in increased crop productivity. Spent wash application at higher doses could cause a buildup of salts, particularly Potassium in the soil. Most of the authors however, do not report any negative impact of spent wash on soil. Nutrient uptake was generally observed to be enhanced. Some authors attribute the higher uptakes of N and Mn to the presence of readily decomposable sugars in the liquor and the P and Mg uptakes due to the lignin and tannin contents. Ferti-irrigation as described by the CPCB involves achieving a BOD of less than 800 mg/L, storing treated effluents and diluting them prior to irrigation to suit the soil and crop type. It also says that it could be restricted to one or more irrigations within the command area. Application of spent wash could be done in alternate years and further irrigations to be done using fresh water. More research may be required on the risks of infiltration of vinasse into soil, into groundwater and on the impacts on human health due to use as a ferti-irrigant. Fertigation may have to be practiced under strict control.
Also See:
- Indian Distillery Industry, Manufacturing Process, Composition of Effluents, Environmental Impacts, Treatment Technologies
- Distillery Effluents Utilisation in Agriculture
- Using Distillery Spent Wash For One Time Controlled Land/Presown Land Application
- Using Distillery Spent Wash For Bio-composting
- Some International Practices on the Use of Distillery Spent Wash in Agriculture
- Using Distillery Spent in Sodic Land Reclamation