Distillery wastes improve sugarcane, rice production

Los Banos, Laguna – Distillery waste or slops, when applied to a sugarcane farm at planting time, can improve the growth of sugarcane.

The improvements are in terms of increased tonnage, healthy growth stand, and high percentage of juice sweetness (Birx), it was found in a research done by the SEAMEO Regional Center for Graduate Study and Research in Agriculture (SEARCA) based here.

The study also noted that yield of paddy more than doubled when grown on soil saturated with slops prior to planting, applied with fresh water for land preparation, and later irrigated with fresh water throughout.

The year-long study was conducted by SEARCA team composed of Dr. Rodrigo Badayos, Dr. Arturo Gomez, Dr. Nerlita Manalili, and Prof. Moises Dorado. It assessed the potentials of a distillery’s treated slops as irrigation water and soil enhancer to rice and sugarcane.

Specifically, it sought to, among other things, resolve such issues as the operation of a distillery in terms of building up its capacity to manage waste; and use of distillery wastewater and sludge for irrigation and fertilization of crops.

The firm studied is one of the 11 distilleries in the country. To improve its wastewater quality and to pass the requirements of the Department of Environment and Natural Resources (DENR) Pollution Adjudication Board, it set up a P90-million wastewater treatment plant.

During the normal operation of any distillery plant, slops (liquid waste) and sludge (solid waste) are produced. Many distillery plants usually maintain lagoons to contain either slops or sludge

The distillery studied had several lagoons for both slops and sludge located near the plant. Moreover, in the absence of alternative disposal system, it disposed of small quantity of slops from its lagoons directly into the adjacent river to accommodate new slops.

This displeased residents along the riverbanks and resort owners along the coast of the bay where the tributary river drained its water. They complained either directly to the firm or to the DENR that the slops killed fish and crustaceans.

The issue became more serious when "fish kills" occurred in the main river and its tributaries, prompting the people to ask the distillery to stop operation.

Several DENR-coordinated public hearings have been conducted between the firm’s staff and the community folk to resolve the issue.

Everybody was amenable that the firm should have a more acceptable alternative waste disposal system if it is to continue its operation.

Thus, the SEARCA research was conducted.

Two types of experiments were done – field and pot.

The field experiment was carried out to generate data and confirm farmers’ observation that slop improves sugarcane growth.

The SEARCA researchers noted that seedlings emerging from the slop-irrigated areas after a month appeared healthier, showing predominantly dark green leaves compared with the light green leaves of seedlings from the untreated (control) farms.

Moreover, the slop-irrigated sugarcane remained robust and green until the tenth month when plant samples were prematurely harvested for evaluation.

"The study has proven that slop helped maintain greener, taller, bigger girth and also heavier cane plants," the researchers reported.

Furthermore, the juice of the 10-month-old irrigated sugarcane showed three percent higher Brix reading (percent sweetness) compared to the untreated ones.

"Yield estimate gave about 130 tons per hectare in slop-treated field as against 100 tons per hectare in the untreated field," they said.

The slop-treated sugarcane on pots was also taller, bigger in diameter, and with darker green leaves throughout the experiment.

All the slop-irrigated sugarcane weighed heavier than the control. However,, the Brix reading of the eight-month cane plants in all levels of slop treatments turned out lower than the control plant.

The SEARCA researchers explained that the low sugar content of the harvested sugarcane was attributed to its very young age.

They said that a 12-month sugarcane variety normally significantly starts to store sugar by the tenth month. Therefore, there was nothing wrong with the additions of slops.

In the rice portion of the research, the mature rice plants were harvested after 120 days. Despite the damage caused by birds, the yield averaged 5.52 tons per hectare.

"Rice farmers used to harvest an average of 2 t/ha of grains in the same field without slop treatment," the researchers said.

They concluded: "To maximize the benefit of slop application on sugarcane and rice, it may be best to apply slops in diluted form through the irrigation water."