Distillery wastewater good as sugarcane fertilizer

Effluents (wastewater) of sugarcane distilleries are good fertilizer for sugarcane.

This was found in two related studies done by a research team of the UPLB-National Institute of Molecular Biology and Biotechnology (BIOTECH) composed of M.L.Q. Sison, J.P.V. Magbanua, E.C. Bugante, F.G. Torres, F.R.P. Nayve Jr., V.P. Migo, and W.L. Fernandez.

The project, titled "Agro-recycling of distillery effluent for sugarcane," was funded by UPLB-BIOTECH and conducted in partnership with three distillery companies in Batangas.

The rationale behind the study was that a major problem of sugarcane distilleries is the large volume of highly pollutive wastewater called distillery effluents. For every liter of alcohol produced, 10 to 15 liters of distillery effluents are generated.

Nonetheless, the UPLB-BIOTECH researchers said, distillery effluents are good fertilizer material because these are rich in organic matters, nitrogen, phosphorus, potassium, and other elements. Moreover, these are devoid of heavy metals or toxic substances.

"Recycling distillery effluents as fertilizer saves the environment from pollution and the farmers from the high cost of fertilizer inputs," they pointed out. "Likewise, it is expected to improve sugarcane yield."

In the project, field experiments were done in two sugarcane plantations: Site 1 in the town of Tuy and Site 2 in Lian.

Following are some of the significant results of the research:

• Plant height of sugarcane significantly increased at three and six months after planting (MAP) when fertilized with distillery effluent. The response was similar in plants fertilized with urea at 17 kilogram nitrogen per hectare.

• More tillers at six MAP were produced in plants fertilized with a combination of distillery effluents and nitrogen fertilizer at full and half rates.

• Plant leaves were wider, greater, and healthier when treated with distillery affluent.

• Yield increased by 64-71 percent when fertilized with distillery effluents alone and by 58-61 percent in combination with area.

• Sugarcane yield in combination treatments increased by as much as 93-95 percent over the control (three treatments), including the control, were studied, with sugarcane cultivar Phil 75-44 used in Tuy and Phil 87-15 used in Lian).

• Distillery effluents alone can substitute for the recommended rate of 173 N kg/ha and can supplement the other organic matters and elements.

• Ratooned cane performed better over the control.

The researchers also cautioned that application of mineral N and effluents beyond the sixth month may retard can ripening, decrease cane yield, and increase juice ash. — RAF