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1st Part Identification of system boundary to be evaluated 2nd Part Monitoring of milling operation and waste management practices 3rd Part Mass balance analysis of the system subjected to the system boundary defined in the first part Evaluation of a Zero Discharge Technology for Palm Oil Mill in Malaysia: A Real Case Study In Sabah MALAYSIAN PALM OIL BOARD (MPOB) Ministry of Plantation Industries and Commodities No.6, Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia. Tel: 603-87694672 Fax: 603-89262971 Website: http://www.mpob.gov.my -------------------------------------- Abstract -------------------------------------- Rapid growth of palm oil production in Malaysia in the last few decades has caused major problems to the environment; namely the large waste effluent discharged into the rivers and methane emission from palm oil mill effluent to the atmosphere. This study evaluates the performance of zero discharge technology in palm oil mill through management of solid and liquid waste produced at the end of the milling process. This technology suggests that the total composting of solid waste sprayed with liquid waste in the presence of thermophilic microbes will be able to evaporate all the liquid, thus resulting in zero effluent discharge. Constant monitoring of a newly developed mill having a composting plant, involving important variables in the palm oil processing and composting process has been completed. We found that total evaporation of water from the liquid waste through the composting process was successfully achieved during the 12 months of continuous monitoring, subject to some limitation caused by palm fruits processing capacity. The nutrient-rich compost was in excellent condition for use as a fertilizer in oil palm plantation. While others are making efforts in complicated treatment of waste effluent, this technology appears to have put itself in an attractive position for eliminating wastes from palm oil mills. This holistic design of zero discharge technology is a promising technology for the palm oil mills to address the concern of Malaysian government towards producing greener and cleaner technology 1. The rapid growth of palm oil industry has also witnessed a significant increase in the production of effluent and other biomass by products from palm oil mills, causing an adverse impact on the environment , if not treated effectively. Malaysian palm oil mills still practicing effluent discharge into water courses continue to be cause for grave concern to Malaysian regulatory bodies and NGOs particularly Sabah 2. This has prompted the state government and the local authority to revise down gradually the limit for biochemical oxygen demand (BOD) from 1,000mg/L in 1980 to 100mg/L in 2010. The proposed limit of 20mg/L to be implemented in the near future has triggered the industry to vigorously accelerate its research activities to comply with the impending regulations 3. An ideal solution promising to be capable of addressing the present pollution problem is the zero effluent discharge system, the dream of all millers 4. A commercial zero discharge mill in Sabah has been evaluated for its efficiency and performance 1. The mill integrated with the effective management of waste was able to achieve zero discharge based on this study 2. Production of nutrient rich compost is very much valuable for the plantation 3. The composting plant capacity has to be tailored to serve the requirement of the designed mill processing capacity. If the mill decides to process more crop than what the composting plant is capable of handling, there will be an accumulation of surplus effluent. The authors wish to express their gratitude to Nexus Technology Consultancy for the assistance provided throughout the study as well as the mill management for allowing us to conduct the study at Yuwang Palm Oil Mill. Results Acknowledgement Introduction Key design of the zero discharge technology for palm oil mills and the limitations of the technology are summarized as below: 1. The mill was designed with the primary objective of using minimum water for processing. For this the use of zero dilution decanter (eco-D) helped to reduce water addition. The isolation of water used in kernel recovery station from the palm oil processing line effectively reduced mill water usage from typical value of 0.65t to 0.55t per tonne FFB processed 2. The designed evaporation capacity of the composting plant is subjected to the limit of processing of FFB up to 600 tonnes per day as shown in Fig. 3 3. Waste water from the mill was treated separately instead of lumping them all as POME. The decanter slurry and sterilizer condensate were mixed with shredded EFB for composting as shown in Fig.1 4. Highly active thermophillic microbes associated with the composting process were able to perform massive evaporation of 330 tonnes of water per day (Fig. 2) from the compost heap with the aid of a mechanical compost agitating machine 5. Since the composting plant capacity is strictly limited to the 600 tonnes per day FFB processing, any excess FFB processed would result in an accumulation of effluent for which buffer ponds will be needed for its storage. This happened from October onwards (Fig. 3) but the mill had the buffer ponds for the storage of the excess effluent. 6. Buffer ponds were purposely built to retain the excess POME as shown in Table 1, and may be recycled in composting plant later during the low crop season. 7. Nutrient-rich compost produced at the end of the process was dispatched to the plantation as a valuable bio-fertilizer Discussion Nu’man Abdul Hadi, Zulkifli Ab Rahman, Yahaya Hawari, Keng Beng Keong Figure 2: Evaporation of POME from compost heap throughout 2011 – weekly average Methodology Subject Description Details MT / m 3 A Total POME produced by mill 9 th Oct – 31 st Dec 2012 33,140 B Total POME absorbed & evaporated 28,185 C Excess POME to buffer ponds 4,955 D Rainfall (9th Oct – 31st Dec 2011) 0.4215 m x 3,200 m 2 1,349 POME Accumulated (C + D) 6,304 E Buffer pond 1 capacity 30 m x 20 m x 2.2 m 1,320 F Buffer pond 2 capacity 30 m x 20 m x 2.2 m 1,320 G Buffer pond 3 capacity 50 m x 40 m x 2.2 m 4,400 Buffer Ponds Capacity (E + F + G ) 7,040 Figure 3: Daily average of FFB processed throughout 2011 – 30 days moving average Table 1: Mass balance on the accumulation of water during the excessive operation of mill throughput Figure 1: Process diagram of zero discharge technology showing the composting plant integrated with the palm oil mill processing line Palm Oil Mill Sterilizer Condensate Composting Plant Leachate Pits Buffer Ponds Leachate Drain Decanter Slurry EFB Leachate POME CPO Palm Kernel FFB Compost (To Plantation) System Boundary Conclusion The evaluation study was conducted in Yuwang Palm Oil Mill in collaboration with Nexus Technology Consultancy, throughout the whole year 2011. The overall approach of this study was conducted in three parts:
