ABSTRACT
New technology in organic waste management converts poultry manure into high-quality biofertilizer using effective microorganisms (EM). The high price of currently used imported EM limits compost production. Without treatment, the application of untreated manure in agriculture will contribute to fly problem. Therefore, it is necessary to find locally available, cheap and effective EM alternatives. This study aims to determine the suitable local EM based on compost quality in terms of NPK values, nutrients and cost. Five batches of chicken manure were prepared with two control setups of manure only and manure with sawdust (C/N of 30:1), while others were manure treated with different commercial EMs. The highest temperature recorded is at 45℃ and pH between 4.0 to 6.5. Composts matured at day 24, 27 and 45 for EM1 (local), EM3 (imported) and EM2 (local), respectively. The highest values obtained for K (412 ppm), Na (233 ppm) and Mg (54 ppm) with low energy (11.7 kJ/kg) and cost (RM 171/ton manure) suggest that EM3 is the best option. However, higher NPK values of EM2 and faster maturation of EM1 could propose for promising local substitutes. Future work should investigate the potential mixture of these EMs for optimum composting time and quality.
INTRODUCTION
As high poultry consumers’ country, Malaysia is estimated to have per capita consumption of 46.89 tonnes annually. A 2018 Annual Economic Statistics reports that in 2017 the gross output of the livestock industry reached RM 15,185.6 million (Majid and Hasan, 2014). This resulted in a massive amount of waste produced by the industry and created environmental problems such as air, water and land pollution (Smith,1994). It also attracts flies as the nutrients found in the manure serve a perfect breeding ground for flies' larvae (Hulley, 1983). Thus, a need to manage poultry waste is necessary. Turning waste into value-added products, poultry industry is facing challenges. Combating the problem of waste management, the industry is known for collaborating with government and local research institutions to overcome the challenges.
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Poultry waste can be directly sold and used as biofertilizer. However, this practice needs to be upgraded by manure treatment beforehand. Conventionally, pesticide spraying and anaerobic digestion are practiced as manure treatment. These two methods, however, are impractical in long term. Pesticide might induce algae bloom and endanger nearby aquatic lives (Khan and Ansari, 2005) while the other method requires a large tank which adds footprint and operational and high in maintenance cost (Gujer and Zehnder, 1983).
Positive results of manure composting are shown by Chan et.al (2011) and Lokman et al (2013). High amount of feeding results some are excreted with manure without being digested by the broilers. These bypass nutrients and organic matter are convertible into high-quality biofertilizer. Moreover, manure composting can be enhanced with addition of EM. This mixture of microorganisms was first discovered in 1982 and was developed to enrich any process that can be improved, included composting. The improvements such as removing foul odors and reducing composting period are important for sustainable practice (Voběrková et al., 2017).
This study was conducted under a collaboration between Dindings Poultry Processing Sdn. Bhd. in Manjung, Malaysia. It aims to enhance the chicken manure composting process while tackling the fly problem to lift the societal burden and support Manjung tourism industry. Dindings Poultry Processing currently uses an imported EM. The cost of this EM contributes significantly to the overall cost of composting. The situation shows less demand for EM-ed compost as the price is still not affordable for farmers. Hence, a more affordable locally produced EM for chicken manure composting is required to offset the high production cost.
In one day, Dindings aerobic composting plant processes about 30,000 kg of raw chicken manure. Unfortunately, by the dosage of 0.6 kg EM/ton raw manure and price of RM 57/kg EM, the daily cost of EM is RM 1,026. Besides, this EM treated compost is not in the selected by market due to low NPK increment. Reducing fly attraction is the only motivation to compost.
This study aims to determine an alternative EM that is locally available, low cost and able to produce higher quality compost. Compost parameters in terms of NPK value, energy content, micronutrient concentration, and cost were analyzed for EM and non-EM treated composts.
MATERIAL AND METHODS
Material
Chicken manure was obtained as an in-kind contribution from Dindings Poultry Sdn. Bhd. in Manjung. Effective microorganisms were EM1 (local company, EMRO), EM2 (local company, J-Biotech), and EM3 (imported EM used by Dindings Poultry). Sawdust was obtained from Wan Sang Sawmill Enterprise Sdn. Bhd. as an in-kind contribution.
Experimental
Feedstock Preparation
Two batches of control experiment consist of chicken manure alone and chicken manure with sawdust was prepared. Sawdust was used as a carbon adjuster to produce compost feedstock at the C/N ratio of 30:1. These are labelled as EM0 and CM30, respectively. Compost with C/N 30 is generally accepted as the healthiest compost (King and Blesh, 2018). EM1 was prepared by the activation method.
A mixture of molasses, water, and EM1 were stored at least 7 days with built gas up released every 3 days. Dilution of EM2 was done by mixing 20 parts of water with one part of EM2. Direct usage of EM3 required no dilution nor activation. All EMs prepared were stored under room temperature with no sunlight. Table 1 summarizes the properties of EMs used in this study.
Aerobic Composting
The set up consists of a holed plastic container with a protective layer of nylon net. Five batches of compost each weighted at 5 kg were treated with EMs according to suggested application dosage and let to compost for 45 days. Every 3 days, the temperature and pH of the compost were recorded in triplicate using a GoerTek digital soil multimeter and the pile was re-mixed. Water was added into the pile in case of a dry condition to maintain moisture level between 40 to 60%. EM was added weekly for EM compost batches. The moisture content was determined by taking 5 grams samples and dried at 105 for 24 hours. Initial and final weight of samples were also measured. After drying, it was placed in desiccator and reweighed.
Characterization
Centralized Analytical Lab (CAL) of Universiti Teknologi PETRONAS is an internal lab that helped to perform the characterization. Phosphorus content was analysed by UV– Vis Spectrophotometry; Carbon and Nitrogen content was analysed using Perkin Elmer 2400 series CHNS Analyser; K, Na, and Mg concentration were determined through Atomic Absorption Spectroscopy and the energy was by bomb calorimetry. A clear liquid sample was prepared through centrifugal separation by LaboGene for AAS.
DISCUSSION
Temperature and pH profile
Temperature and pH measurements were used to determine the maturation period of compost. Results variation is expected as the experiment was conducted outdoor under a covered shelter. Triplicate readings were done to minimize this variation. All compost reached maturity at the end of 45 days.
The highest and lowest temperature recorded was 45℃ and 27℃, respectively. During day 15 to 20, low temperatures were recorded which after raise back to their normal range. However, comparing EM treated compost with the control batches (EM0 and CM30), batches without EM have a more irregular pattern of temperature and pH. This is due to the natural degradation process in the control batches which were easily disturbed by external factors such as outdoor weather. With regular EM addition, EM treated composts can adjust towards these changes more readily from the microbial activities.
Temperature data suggests the temperatures are in the mesophilic range which is under 40. The highest temperature was obtained only by CM30 due to the addition of sawdust that increased the heat inside the compost system. An optimum compost temperature is in a thermophilic region that is between 41-122. Stable temperature data has been achieved by EM1 and EM3 which indicates a maturation. Thus. the system was at its optimum range despite the temperature interval is not the thermophilic range. A trend of temperature cycle can be seen at composting day 3- 9, 10-15, and 18-23 or about 5-6 days long. This cycle is divided into four stages which are mesophilic, thermophilic, cooling down and maturation period (Sánchez et al., 2017). Cycles are repeated until maturation is achieved.
In the first days of composting, all pH was going down lower than initial pH. Throughout the composting, pH is fluctuated. Eventually, composts with EM are significantly more acidic with the lowest value of 4.8 recorded in EM3. The reduction of compost pH is due to organic acids that naturally prepares the compost to be acidic. Organic acid naturally was produced in all batches. However, EM1 and EM2 are known to have organic acids inside their formula. High probability that this is why compost pH might have gone towards extreme acidic condition. (Sánchez, 2017).
Compost characterization
A sharp peak in K+ value of 400 ppm concentration is found in EM3 as the highest amongst samples. EM1 and EM2 also show high K+ values of 213 and 276 ppm, respectively. All samples show similar trend for Na+ and Mg2+.
Fertilizer is one of minerals nutrient sources for the plant. It is usually sold in the market labelled with NPK value. Commonly, NPK is used to match the requirement of nutrients. Based on the NPK ratio shown in Table 2, NPK ratio is the lowest in EM3. The highest in K value is found in EM1 and EM2 is the highest in N and P values. EM1 is a better option to increase N and P values whereas K values can be enhanced by EM2. To obtain the best NPK value, a mixture of EM1 and EM2 can even increase the ratios.
Another product of composting is the heat produced by the microbial activity (Sophia and Sreeja, 2017). As a form of energy, compost heat can be utilized. A range of 11-15 kJ per kg of com post is available to be used. The highest energy is produced by sawdust addition. This low density material filled the compost and made a suitable condition production (in heat), especially by using solid EM (EM3) with less moisture as it to produce more heat. However, composting, in general, is seen to increase the energy eliminates the buffer of heat production (moisture) like in EM1 or EM2.
Cost analysis
Based on the cost calculation in Table 3, the lowest cost (RM171) is obtained by EM3 followed by EM2 (RM547) and EM1 (RM656). The gross estimation is based on a bulk purchase price of EM3 but the off-the-shelf price for EM1 and EM2. This approach resulted in significant cost variation. Only by knowing the bulk purchase price of EM1 and EM2 or the off-the-shelf price of the imported EM3, more accurate cost estimation can be done. Lack of information on these EMs is due to trade secrets which have imposed limitations in our cost analysis study.
Based on the NPK ratio of the compost, which is the indicator that consumers might look at, a higher price can be set for compost treated with EM1 and EM2. This can offset the relatively higher cost of the EMs. Future research should explore the potential of growing own EM or recycling some amount of matured compost as a composting starter. This way, the EM cost can be significantly reduced will ultimately contribute towards the overall plant's profit.
CONCLUSION
In conclusion, the highest temperature recorded is at 45℃ and pH is in between 5.0 to 6.5. The maturation is reached by EM1 (local) and EM3 (import) in 24 and 27 days, respectively which followed by EM2 at the end of the observation period, day 45 The highest values obtained for K (412 ppm), Na (233 ppm) and Mg (54 ppm) with low energy (11.7 kJ/kg) and cost (RM 171/ton manure) suggests for EM3 as the best option. High NPK values of EM2 and faster maturation of EM1 could be proposed as promising local substitutes. Future work should investigate the potential mixture of these EMs for optimum composting time and quality. Moreover, the exploration of the potential of utilizing various farm litters and waste from meat processing plants as growth media for in-house EM breeding is highly on demand. This approach will promote circular economy activities revolving poultry industry by-products that are presently sold at low cost or landfilled.
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