RESULTS AND FINDINGS ON THE USE OF TREATED DISTILLERY WASTES AS INPUTS FOR AGRICULTURAL PRODUCTION – A WASTE MANAGEMENT APPROACH TO CLEANER PRODUCTION

Drs., Rodrigo B. Badayos, Nerlita M. Manalili and Prof. Moises A. Dorado

SEAMEO Regional Center for Graduate Study and Research in Agriculture (SEAMEO-SEARCA)

gs@mudspring.uplb.edu.ph

ABSTRACT

The research efforts are geared towards assessing the agricultural potentials of treated distillery slops as irrigation water and soil enhancers. Comprised of an evaluation of existing soil and water characteristics and an assessment of the required intervention for current and proposed operational systems, the project lends empirical and scientific support to an agricultural cleaner production initiative not only where positive production results were achieved but the suggested manner, timing, rate of application of treated slops on sugarcane-based alcohol distillery and rice were likewise arrived at.

Findings show that slops application on field trials at planting time, improves growth of sugarcane and is manifested in terms of increased tonnage, healthy growth stand and high percentage juice sweetness (Brix). Similarly as per pot experiments sugarcane irrigated periodically with diluted slops performs better than sugarcane grown on soil saturated with slops only once at planting.

In the case of rice seedling, survival difficulty were established when planted on slops puddled soil and subsequently irrigated with slops also after planting. Productivity wise, yield of paddy rice more than doubles when grown on soil saturated with slops prior to planting, applied with freshwater for land preparation and later irrigated with freshwater throughout the time water is demanded by the plant.

Rice yield is higher when irrigated with diluted slops. It is much better than if soil is first saturated with slops, applied with fresh water for land preparation and irrigated also with fresh water at the other stages of the rice plants.

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

Caution, however has to be undertaken as High rate of application of slops on rice and sugarcane grown on sandy textured soils may cause contamination of shallow watertable.

Slops contamination of ground water underlying sandy soil may be minimized through well-regulated slop application.

INTRODUCTION

Asian developing countries, the Philippines in particular, are confronted with the challenge of pursuing sustainable development anchored on agriculture and fueled by industries. The agroindustrial challenge is made more difficult by the fact that a balance need be struck between agriculture and industries while at the same time addressing natural resource concerns.

Private industrial firms in the implementation of value-adding activities initially paved the way for agroindustrial development in the ASEAN. Since value-adding processing activities generate wastes that may be proven harmful to natural resources, the very sector that fueled agro-industrial development are now facing environmental censure.

Previously pursued on a sectoral approach, where the industrial sector process what the agricultural sector produces and wait for the government agencies to undertake environmental control, increased awareness to environmental issues binds the said sectors to address agroindustrial problems jointly.

One such sector moving along this line is the sugarcane distillery sector. Distilleries using sugarcane as their principal input to manufacture alcohol in the Philippines have the most challenging waste disposal problems. Their operations result to disposal of wastewater and sludge to rivers, which is being questioned by environmental protection standards of the national government through the Department of Environment and Natural Resources (DENR).

The conflict between privately-owned distilleries and the government, which, if left unabated, has debilitating effects to the whole industry. For a sector that contributes PhP3.6 billion pesos of taxes annually out of a 360 million gauge liters of alcohol produced, not to mention taxes from secondary products such as multiple uses ethyl alcohol and CO2 for beverage production, the picture is bleak unless alternative solutions are sooner arrived at. Bleaker are the prospects of sugarcane farming households who are dependent on distilleries as markets for their produce.

THE SITUATION

Alcohol distilleries in the Philippines remain in a bind-solving problem of factory closure as a result of their failure to find acceptable option to dispose slops. Agro-industrial liquid wastes are usually disposed of through channeling them into any bodies of water, quite opposed to the issue of cleaner production.

There were serious thoughts of recycling slops to irrigate agricultural crops but none so far has successfully set a sustainable system that works well and is acceptable to farming communities. The connotation of the word wastewater to the communities seems so difficult to erase. Thus, earlier attempts to recycle slops to agriculture encountered strong resistance from farmers and environmental advocates.

If efforts to recycle slops to agriculture failed before, will it succeed this time? What would possibly turn the situation around?

A. The Firm

DyZUM Distillery Inc. (DyZUM) is one of the 11 distilleries in the country that is in a very unique situation this time. In its desire to improve wastewater quality and to pass Pollution Adjudication Board requirements of DENR, the management ended up establishing a 90-million peso worth of wastewater treatment plant. The plant is basically a methane generator that utilizes wastewater from the alcohol distillery. The combined anaerobic and aerobic wastewater treatments therefore enable the company to improve waste product chemical composition tremendously more than enough to pass DENR Administrative Order (DAO) No. 32 requirement. The DAO 32 sets the effluent standards for inland waters specified as class D.

Given this development, the chances of the wastewater's acceptability, as irrigation water looks promising.

B. The Farmers

1. Sugarcane farmers

Two years prior to the start of the research, a number of farmers at the immediate vicinity of DYZUM Distillery Plant were already irrigating sugarcane field with slops at planting time. These early users have in fact attested to observe that slops have improved germination and survival of sugarcane seedlings and that slops maintain healthy growth of cane plants. As more farmers learned, by word of mouth, of the benefits derived from slops when used for irrigation, DYZUM officials get more requests than what they can handle for similar services from sugarcane farmers. The company has in fact required the new slop users to formalize request for slop application to sugarcane fields by signing a contract with DYZUM to protect name of the company. Essentially, in the contract, DYZUM will irrigate sugarcane farms with slops free of charge while farmers assume the management of their respective farms. Furthermore, that the company will be free from any financial liability should anything happen to the crop.

2. Rice farmers

Early use of slops on paddy rice was not as encouraging as in sugarcane. From the recollection of some paddy rice farmers, when primary (unprocessed) slops were used to irrigate rice paddy fields, farmers observed that panicle initiation was delayed, crop stand was highly vegetative and the few harvested grains taste and smell like slops. This observation has resulted to paddy rice farmers totally rejecting slops to ever intentionally or accidentally applied to rice paddies.

C. The Research Initiative

1. Problem of slops storage and disposal

During the normal operation of any distillery plant, slops and sludge are produced. These wastes, however, will have to be disposed off regularly to maintain operation of the plant. Many distillery plant including DYZUM usually maintain lagoons to contain either slops or sludge. DYZUM has several lagoons for both slops and sludge located several meters from the plant. The small amount of sludge that was separated from the slops is being kept in a separate and smaller lagoon located closer to the distillery plant. Moreover, in the absence of alternative disposal system, DYZUM was disposing in small quantity old slops from their lagoons directly into the adjacent river (Bagbag River) in order to accommodate new slops.

The above practice of slops disposal on river has displeased many residents along the riverbanks as well as among resort owners along the coast of Nasugbu Bay where Bagbag River finally drains its water. They complained either directly to DYZUM or through the DENR that slops disposed off on river allegedly kill fish and crustaceans. Incidentally, catching of fish and crabs including shrimps is helping support the livelihood of some people residing near the riverbanks. And at the coasts, the water is tinge with brown color with the incorporation of slops. The brownish color of water is very unattractive for beach swimmers.

Several public hearings were conducted between DYZUM staff and members of nearby community, which were coordinated by DENR personnel, to help resolve the issues on slops disposal. The issue becomes very serious especially during that parts of the year when fish kill occur near the mouth of Palico River and its tributaries such as in Bagbag River. In fact for several times, DYZUM were asked to close its operation because of the said issue. Everybody is amenable that DYZUM should look for a more acceptable alternative disposal system before it will be allowed to continuously operate. Offshore disposal of slops was considered as an alternative for river but this option has yet to be studied first before it can be implemented.

The research project was formulated to help Dyzum, in particular, and distilleries in general to find alternative options to dispose wastewater. Use of slops from final clarifier to irrigate sugarcane and paddy rice to compliment DyZUM existing wastewater treatment system.

OBJECTIVES

The study, in general, aims to assess the potentials of Dyzum's treated slops as irrigation water and soil enhancers to rice and sugarcane.

Specifically, It was made clear to the company (DYZUM) with concurrence from the EMB-DENR personnel that all efforts to be undertaken by SEARCA researchers were geared towards the resolution of the following issues:

The operation of the distillery in terms of building up their capacity to manage waste.
Use of distillery wastewater and sludge for irrigation and fertilization of crops.
Crop potential and cost benefit of applying effluent to an optimum hectare of farmland.
Suitable cropping pattern that will continuously be dependent on distillery wastes utilization.
Type of hydraulic system suited to distribution of slops as irrigation water.
Related issues on health, social and environment.
Other uses of slops and the empty lagoons.

CONCEPTUAL FRAMEWORK

The one-year research project which commenced last December 1998 is of three components the first being an evaluation of the existing soil and water characteristics followed by an assessment of the required intervention for current and proposed operational systems. The results of the former determined the applicability of the recommended measures for the irrigation of existing crops and new crops found suitable for the site, and the suggested sludge’s rate of application if usage is found feasible.

Completion of soil and water evaluation helped in the design of irrigation system that matches the requirement of sugarcane and paddy rice, the major crops of farms near the Plant, and possibly other crops suited to the condition of the farms. Figure 1 illustrates the conceptual framework of the study.

The development of a comprehensive wastewater management system, required generation of information related to quality of slops for irrigation, description of soil topography and geology, information on hydrology and climate, drainage condition, existing irrigation system if any, and socio-economic implication of the system.

General research methodology

Prior to the conduct of irrigation experiment, SEARCA research team makes it a point to secure important related information that will support the study on irrigation. It therefore carryout the following activities:

a. Study the operating system of the plant especially the part related to the waste management.

b. Conduct soil survey to map different soils in the study area and learn soil characteristics that can affect application of slop.

c. Identify potential cooperators for both sugarcane and paddy rice.

d. Make analyses of slop stored in the company lagoons.

e. Conduct lysimeter study to evaluate behaviour of slop applied on soil.

The team applied field and pot experiments to study the potential of slop for irrigating sugarcane and paddy rice.

The field experiments made used of the sugarcane and paddy fields located at the immediate vicinity of the distillery plant. On the other hand, the pot experiments were set-up at the screen house of Department of Soil Science at University of the Philippines Los Banos (UPLB).

The field experiment on the use of slop for irrigation

Sugarcane. The experiment wanted to find out how sugarcane will respond when irrigated with slop. In this experiment, newly planted fields were flooded with slop pumped directly from the lagoons near the plantation. Slop was applied once only in furrows using rubber hose to direct the flow of slop. Slop usually stays on furrows for few minutes before draining into the ground. Drained of slop is quite fast on medium textured soil.

The sugarcane cooperators took care of the growing sugarcane and implemented all of the necessary operations for maintenance. Meanwhile, the research team visited the study fields 7 times during the entire duration of the experiment to make observation and to collect plant and soil samples for evaluation.

Rice. The study aimed to evaluate response of rice plants grown on soil initially flooded with slop. Paddy fields selected for the experiment were under fallow and were generally dry when the study started. The slop was applied once preparatory for land preparation. The slop pumped from the nearby lagoon was conveyed to the individual paddy using rubber hose. Slop flooded the paddy overnight. The following day after soaking the paddy with slop, the field was plowed once and harrowed twice. The land preparation lasted for more than one week. Transplanting of rice seedling was carried-out right after the completion of land preparation. The cooperators maintained growing rice crop. The research team visited the study area five times to observe and to collect soil and plant samples for assessment.

The pot experiment using slop for irrigation

Sugarcane. The pot experiment was designed to test response of cane plants grown on soil saturated with different volumes of slop. The canes were planted on pots filled-up with twelve (12) kilograms of topsoil taken from soil named as Lipa series. The twenty pots were laid-out following the Randomized Complete Block Design (RCBD) with four (4) treatments and replicated four (4) times. The treatments used are shown below (Table 1):

Table 1. Treatments used in sugarcane pot experiment.

Treatment Number	Slops Treatment
T1R1-R3	Saturated with 7 liters of slop plus best fertilizer rate.
TIR4	Saturated with 7 liters of slop.
T2R1-R3	Saturated with 5 liters of slop plus best fertilizer rate.
T2R4	Saturated with 5 liters of slop.
T3R1-R3	Saturated with 3 liters of slop plus best fertilizer rate.
T3R4	Saturated with 3 liters of slop.
T4R1-R3	Irrigated with 50% slop dilution plus best fertilizer rate.
T4R4	Irrigated with 50% slop dilution.
T5R1-R3	Control plus best fertilizer rate.
T5R4	Control

To saturate soils on pots, holes on pots were first plugged with rubber stopper. Based on the designated treatment, pre-measured volume of slop was poured little by little into the soil contained in pots. After slop saturation, soils were allowed to airdry. Later, air dried soil on pots was loosened using hand trowel. Then, two cane points were planted for each pot thinned to only one after one month. Half of the fertilizers treatment were applied after thinning. The other half three month after planting. For maintenance, plants are watered as the need arises.

Samples of untreated soils were also taken for laboratory analysis.

Cane plants were regularly observed for any damage. As part of monitoring procedure, plant height was taken four months after planting. After eight-month, cane plants were harvested prematurely to comply with reporting requirement. During the time of harvesting, the following were taken and recorded, namely: length of millable stalks, diameter of millable stalks, average weight millable stalk, and Brix (% juice sweetness).

Rice. The pot test on rice planned to evaluate how much volume of slop may be used to saturate soil for growing rice. In addition the study intended to find out if irrigating diluted slop will be better compared to one time slop saturation. Moreover, the experiment aimed to find out if additional commercial fertilizers are needed to supplement slop.

Topsoil of Lipa series was used for the pots test. Pots were labelled and later sealed to prevent leakage of any fluid before soil was added. The following were the treatments used in the study (Table 2):

Table 2. List of treatments used in paddy rice pot experiment.

Treatment Number	Slops Treatment
T1R1-R3	Saturated with 7 liters of slop plus best fertilizer rate.
TIR4	Saturated with 7 liters of slop.
T2R1-R3	Saturated with 5 liters of slop plus best fertilizer rate.
T2R4	Saturated with 5 liters of slop.
T3R1-R3	Saturated with 3 liters of slop plus best fertilizer rate.
T3R4	Saturated with 3 liters of slop.
T4R1-R3	Irrigated with 50% slop dilution plus best fertilizer rate.
T4R4	Irrigated with 50% slop dilution.
T5R1-R3	Control plus best fertilizer rate.
T5R4	Control

Slop was simply poured into the pots with soil for saturation purposes. Slop treated soils were allowed to air-dry for a period of one week. After air-drying, soils in all pots were saturated with freshwater and were puddled later to approximate paddy field condition. Puddling was accomplished using hand trowel. Prior to slop treatment, PSBR 64 seeds were soaked in water for 24 hours and were germinated in small flat basin. Two-week old rice seedlings were transplanted to the prepared pots at the rate of four seedlings per pot. Pots labelled T4 were maintained with diluted slop while all the rest of the pots were maintained with fresh water.

At maturity, the whole plant biomass per pot was harvested. And from the harvested biomass, the following were recorded: dry matter yield, grain yield and productive tiller number. Soil samples from each pot were collected for chemical analysis to observe residual effect of slop on soil.

RESULTS AND DISCUSSION

Description study area, land resources assessment and slop analysis

The DYZUM Distillery Plant seats at the coastline of Nasugbu Bay which belongs to the political jurisdiction of Barangay San Diego, Lian, Batangas. The coastline of Nasugbu Bay is distinctly dry from December until May and wet from June to November, typical of Type I climate of the Corona System. Prevailing air temperature is fairly uniform and ranges only between 22 to 31^oC.

DYZUM Plant is situated on the levees of Bagbag River with slopes of less than 5%. Runoff drains into Bagbag River, a tributary of Palico River. The coastline of Nasugbu Bay and the adjacent plains were built by mostly coarse to medium textured recent alluvium, derived from the ashfall of Tagaytay volcanoes.

Around the distillery plant, there are vast areas of rainfed sugarcane plantations, interspersed with sugarcane are small patches of land planted to paddy rice, corn and vegetables.

Soils at the experimental area are young in terms of profile development. The soil profiles were described as deep, well drained and with medium to coarse texture. Profile textures are generally medium to coarse attributed to the sandy characteristics of the soil parent materials.

Topsoil taken from field used in the study has near neutral reaction (pH 5.7-6.7) and generally contained low amount of organic matter (%OM <2). The rest of the chemical properties of the soils around the vicinity of DYZUM Plant appear in Table 3. To sum up the result of laboratory analysis, soils used for crop production experiment may be considered as low in fertility especially when it will be used for sugarcane and paddy rice.

Table 3. Analyses of composite soil samples before and after slops treatment,

and after harvest of sugarcane.

Soil Properties	Untreated Soil Sample (initial)		Slops Treated Soil at planting	Slops Treated Soil After Harvest
pH	5.93	5.90	7.09	5.63	5.82	5.87
Organic matter (%)	1.53	1.78	2.46	1.96	2.27	1.86
CEC (meq/100g)	28.02	28.38	28.75	24.79	30.70	23.32
Avail P (meq/100g)	5.34	9.98