WO2013169091A1

WO2013169091A1 - Zero discharge treatment system of palm oil mill effluent (pome)

Info

Publication number: WO2013169091A1
Application number: PCT/MY2012/000100
Authority: WO
Inventors: Zhenjia ZHANG; Yuen May Choo; Soh Kheang LOH
Original assignee: Ronser Bio-Tech Sdn Bhd; Malaysian Palm Oil Board
Priority date: 2012-05-11
Filing date: 2012-05-11
Publication date: 2013-11-14

Abstract

The present invention relates to establishment of a zero discharge treatment technology of POME mainly routed in (1) pre-treatment, (2) biological treatment and (3) membrane separation. The ultimate goals of the developed zero discharge POME treatment technology are: (1) produce biogas as a source of renewable energy, (2) zero emissions of POME into the atmosphere, (3) final discharge of BOD 20 ppm or below; (4) clean water for use as boiler feed water and (5) recover potash rich fertilizer, which are of great values to the palm oil milling process.

Description

ZERO DISCHARGE TREATMENT SYSTEM OF PALM OIL MILL EFFLUENT

(POME)

FIELD OF INVENTION

In order to reduce hydraulic retention time (HRT), occupied area and greenhouse gas (GHG) emissions of palm oil mill effluent (POME) treatment and to take advantage of by-products generated from palm oil milling process, an integrated "zero discharge" process mainly routed in "pretreatment - biological processes - membrane separation" is developed based on clean development mechanism (CDM) and sustainable development strategy. Although currently POME is treated in two stages i.e. anaerobic and aerobic processes in a series of conventional ponding systems and other commercially available systems, it is found that biological treatment is not efficient enough to treat the relatively high contents of oil and grease (O&G) and suspended solid (SS) of POME, thus pre-treatment is a necessity in this issue. The present invention features a zero discharge concept which may not only provide ideal solution to current problems faced by the palm oil industry but also helps sustain the environment for better development in the future.

BACKGROUND OF THE INVENTION

In the palm oil milling process, it is estimated that about 1.5 m³ of water is needed to process one tonne of fresh fruit bunch (FFB); half of this amount ends up as POME (Zhang et al., 2007). The raw POME is a thick brownish liquid discharged at a temperature between 80 and 90°C. It is highly polluting and characterized by low pH, high biological (BOD) and chemical oxygen demand (COD), high salt content, and high SS. As a result, a tremendous amount of highly polluting POME is generated annually resulting in a serious environmental impact.

However, POME has also found to contain high soluble organic substances which are good for biological digestion. While anaerobic digestion is widely accepted as an effective method for the treatment of POME, anaerobic treatment of POME alone has difficulty meeting discharge limits due to the high organic strength of POME. Hence, the treatment of POME is very critical to conserve the environment due to the free emissions of biogas from POME and the concern on the quality of the final discharge into a watercourse. Whilst the present tertiary treatment technologies are able to meet the regulatory effluent discharge standards of 100 ppm BOD requirement when they are managed and operated optimally, most of the technologies employed have uncertainties in the plants' performance, and thus do not consistently meet 100% compliance on BOD 20 ppm.

To date, an increasing pressure on environment preservation has been put on all industries generally in finding methods of reusing waste/by-products, for instance through cleaner and low- carbon production, thus mirroring rapid changes in environmental policies. In Malaysia, due to an increasing pressure imposing by the Department of Environment (DOE) on a more stringent regulatory requirement of POME discharged into a watercourse (BOD 20 ppm) in some sensitive areas, especially those involving tourism activities in Sabah and Sarawak, the oil palm industry is required to investigate a wide range of approaches for the treatment of POME. In this context, an innovative approach towards zero-effluent discharge or zero-emissions will enable problem free mill operation. Judging the vast potential of this technology in the near future, collaboration between Malaysian Palm Oil Board (MPOB), Ronser Bio-Tech Sdn. Bhd. and Shanghai Jiaotong University has been initiated to provide a more economical and environmental-friendly treatment through anaerobic digestion and aerobic treatment. It is envisaged that POME can be sustainably reused as a fermentation substrate in the production of various metabolites, fertilizers (Zakaria et al, 2000) and animal feeds through biotechnological advances.

The environmental impact of POME cannot be over emphasized; hence an urgent need for POME treatment measures to achieve a desirable BOD level before it is discharged into a watercourse. Currently, ponding system is the most common and conventional method of treating POME which is able to reduce BOD to the discharge standard of 100 ppm (Ma, 2000; Khalid et al., 1992) but other processes such as aerobic and anaerobic digestions (Yosri et al, 2009), physicochemical treatments (Mohammad and Gapor, 2008; Andrew, 2009) and membrane filtration (Mohammad et al, 2007) may also provide the palm oil industry with a possible insight into the improvement of current POME treatment process. However, the conventional POME treatment based mainly on biological treatments of anaerobic and aerobic systems has been found inadequate and inconsistent in treating POME to a more stringent discharge standard, which unfortunately has led to production of biogas which is not trapped. This is because the high BOD loading and low pH of POME, together with the colloidal nature of the SS, renders treatments by conventional methods difficult.

The bioconversion of organic waste materials to biogas in anaerobic digesters has potential practical and economic implications. The anaerobic degradation of organic compounds consists of several biological reactions and nutritional interaction involving several groups of microorganisms. Biogas produced will be harnessed and used to generate electricity. Biogas harnessing from POME can be carried out using a number of local or foreign technologies. Anaerobic digestion can be conducted in a closed-tank anaerobic digester system, an open digester tank, or in a covered lagoon. Currently, the established techniques used for treating wastewater in anaerobic digestion systems are the continuous stirred-tank reactor (CSTR) (Tong, 2008; Tan, 2008), the up-flow anaerobic sludge blanketed (UASB), or the more advanced expanded granular sludge bed, (EGSB) (Feng et al., 2008). and the up-flow solids reactor (USR) (Lynda, 2008). These are among the most commonly used technologies in Malaysia. Besides, a few improved high rate bioreactors have been tested in the treatment of POME such as the modified anaerobic baffled bioreactor (Faisal and Unno, 2001), anaerobic filter and anaerobic fluidized bed reactor, thermophilic upflow anaerobic filter (Mustapha et al., 2003) and rotating biological contactors in increasing the efficiency of pollution reduction and biogas production (Yacob et al., 2006). Experimental results indicated better treatment of POME compared to conventional practices. However, large scale implementation of any of the improved system is still lacking. The two POME treatment technologies i.e. the anaerobic AnaEG™ and the aerobic BioAX™ employed in this invention for treatment of both organic and biological wastes have been successfully used for treatment of domestic waste (sewage) and other industrial waste. Through the use of these treatment technologies, the environment impact associated with POME could be reduced. On top of that, this effective biological treatment of POME is able to yield useful products such as methane (biogas), organic fertilizers and animal feeds.

The application of raw or digested POME as fertilizer on land was initially thought to be impractical because the effluent discharged has shown evidence in killing vegetation and leading to the blockage of percolation and water logging, thus resulting in anaerobic conditions. However, Wood and co-workers (1979) found that although raw POME would readily cause clogging and water logging of the soil, these problems could be overcome by the controlled application of small quantities of POME at a time. The testing of ground waters after 6 to 12 months of trial applications of raw POME as fertilizer showed no substantial percolation of oxygen demanding or other polluting elements without excessive run-off over the surface during wet weather (Wood et al., 1979). It was thus established that the water quality in the applied areas was unaffected (Dolmat et al., 1987). Oviasogie (2003) later reconfirmed that a proper use and safe disposal of POME in the land environment would lead to improved soil fertility and contribute to environmental sustainability. Results showed an enrichment of the soils with regard to phosphorus, nitrogen, calcium, magnesium, sodium and potassium following the application of the POME. Copper, iron and lead were predominant in their organic forms, while zinc was particularly present in its exchangeable form.

The potential utilization of POME as a cheap organic fertilizer may offer an alternative to the excessive application of chemical fertilizers, especially phosphorus, for which cost is a severe economic constraint. An incorporation of POME may help to increase the organic matter in the soil, which may turn into humus after decomposition and become an active soil component. Thus, POME application would result in changes in the chemical properties of the soil ( Wu et a , 2009).

To date, the oil palm industry is still constantly encountering environmental allegations in its efforts towards implementing sustainable POME management via biogas harnessing to mitigate climate change. Although much has been discussed on a zero discharge or zero emission approach dealing with POME, the industry has not been provided with a proper documentation in terms of the economic viability and practicality, hence a lack of confidence in its implementation.

SUMMARY OF THE INVENTION

The present invention relates to a concept of zero discharge treatment technology for POME comprising three important principles i.e. (1) pre-treatment, (2) biological treatment using AnaEG & BioAX and (3) membrane separation (Fig. 1).

zero discharge POME treatment technology demonstrates the following features

1. Biogas production as renewable energy;

2. Zero emissions of POME into the atmosphere

3. Final discharge of BOD 20 ppm or below;

4. Sludge as fertilizer with high potash (K) content;

5. Recycling of the treated water for boiler use.

Fig.l The developed process scheme for zero discharge treatment technology of palm oil mill effluent (POME)

The first aspect of the present invention provides a method to recover waste oil from POME via a pre-treatment process. Before POME is used in biological treatment, it goes into a complex concrete tank functioning as a pre-treatment and aerobic/clarifier system for waste oil/sludge recovery. The waste oil recovered can be used as technical oil whereas the sludge obtained can be concentrated to become a compound fertilizer. The second aspect of the present invention is the biological treatment technologies used to produce biogas from POME and generate final discharge meeting BOD 20 ppm or below. The biological treatment plant of anaerobic digestion consists of two or more AnaEG steel tanks (dependent on the capacity of a palm oil mill) employing EGSB principle; each tank has diameter and height of 6 m and 16 m, respectively. The two EGSB tanks are designed for running in series or parallel for an anaerobic digestion of POME using a set of valve and two buffer tanks. In AnaEG system, biogas is produced and will be channeled to a biogas generator set whereas a substantial amount of flue gas can be recovered as waste heat for boiler, and the treated sludge can be further made (dewatered) into a compound fertilizer for use in oil palm plantations. To achieve BOD 20 ppm (COD 50 ppm) of POME final discharge into a watercourse, the effluent after AnEG treatment will undergo aerobic treatment in the BioAX system. In addition, removal of ammoniacal nitrogen (NH₄-N) can also be accomplished. The biological treatment plant of aerobic process consists of mainly a BioAX tanks and a nano air flotation.

Further, there is also provided a method to utilize the produced biogas - a set of biogas purifier and a biogas generator set are used to transform the produced biogas (methane) into energy (electricity) for further use (either for use within the mill's vicinity or for grid connection). The biogas generator set (Weifang, 120 kW) comprises of a control system, an ignition system, an electrical governor, a battery charging generator, a base frame and a shock proof pad, etc.

In another aspect of the present invention is a membrane separation technology to further treat the wastewater of POME for reuse or recycling. A series of ultra filtration (UF) and reverse osmosis (RO) systems are used in membrane separation to achieve reclamation of clean/pure water - including two modules of UF having a nominal molecular weight cut-off (MWCO) of 100,000 g/mol and the ESPA-2 RO membrane (Hydranautics, USA) having 99.6% NaCl rejection rate. The products after passing through this treatment are the clean RO water (which can be recycled as boiler feed water to reduce corrosion), and RO concentrate (or RO reject) containing excess liquid potash (K) which can be used as a biofertilizer in the oil palm plantations via irrigation.

The present invention of a zero discharge POME treatment technology has ultimately aimed at producing the following: (1) biogas as a source of renewable energy, (2) clean water for use as boiler feed water and (3) potash rich fertilizer, which are of great values to the palm oil milling process.

The present invention consists of features and a combination of parts hereinafter fully described and illustrated in the accompanying drawings, it being understood that various changes in the details may be made without departing from the scope of the invention or sacrificing any of the advantages of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENT

The present invention relates to a zero discharge treatment technology for POME generated from the palm oil milling process for the production of biogas, effluent discharge with BOD 20 ppm, recycled effluent clean water and potash rich fertilizer. Hereinafter, this specification will describe the present invention according to the preferred embodiments of the present invention. However, it is to be understood that limiting the description to the preferred embodiments of the invention is merely to facilitate discussion of the present invention and it is envisioned that those skilled in the art may devise various modifications and equivalents without departing from the scope of the appended claims.

The present invention is a zero discharge POME treatment system mainly routed in (1) pre- treatment, (2) biological treatment and (3) membrane separation (Fig. 2).

Fig. 2 The developed zero discharge treatment technology of palm oil mill effluent (POME) at MPOB Experimental Palm Oil Mill, POMTEC, Labu i. Pre-treatment of POME

POME which is high in O&G and SS are generally known as obstacles to biological digestion, thus removal of these two parameters is essential in ensuring effective pre-treatment of POME.

The pre-treatment process (Fig. 3) involves rotary screen, grit separator, equalization (EQ) tank, oil-water separation tank, and cooling tower. The gross solids, unexpected mass etc. in the raw POME are screened and removed by the manual grille before oil slick is collected and water separated in the oil separation tank. Due to the high solid content in the effluent, cyclone grit separator is used to separate sand by centrifugal manner. An equalization tank (EQ tank) functions as a buffer for the raw POME to improve the effectiveness of secondary and advanced wastewater treatment processes by leveling out operation parameters such as POME flow, pollutant levels and POME temperature over a period of time. To reduce the temperature of the feed of anaerobic process to the optimum mesophilic condition (35 ± 3°C) which is required before the POME is subjected to biological treatment, a cooling tower is employed.

Fig. 3 The schematic diagram of pretreatment process ii. Biological Treatment

The proposed biological treatment includes AnaEG and BioAX which features for its high efficiency anaerobic and aerobic process respectively compared to the conventional biological treatment methods of anaerobic, facultative, and aerobic degradation. a. AnaEG™ (for anaerobic treatment of POME)

AnaEG™ has been patented as a state-of-art technology for treatment of organic or biological waste (ZL 97 1 03569.5; ZL 03 1 29055.8; ZL 09 1 0050787.1 ; PCT/MY2011/000046). It has the capability to effectively treat a wide range of wastewater and it is particularly efficient for problematic wastewater with high organic content (COD concentration up to 50 000 mg/L). Besides being able to remove 70-95% of organic matter from the wastewater, this technology generates less sludge compared to other conventional aerobic processes. Due to the significant reduction in the amount of sludge produced, it lowers the cost of sludge management. In this system, wastewater enters the reactor from the base and flows through in an upward direction. As it flows through the reactor, organic matter is biodegraded in an anaerobic process. Organic acid and biogas gas are formed in two different layers in the AnaEG ^rM reactor. The generated organic acid forms the bottom layer and is about 1/5 - 1/3 of the overall depth of the granular sludge while the generated biogas forms the upper layer. The AnaEG system provides a method of anaerobic treatment of organic wastewater that uses a simplified plant structure and operating procedures, without setting up of a hydrolysis acidification pool and water back flow process. Organic matter of wastewater can be converted to organic acids then to methane gas completely in just one treatment plant. Acidogenesis fermentation bacteria and methanogenic fermentation bacteria are kept separately while enable the fermentation to happen at the same time. It allows nongranular anaerobic bacteria sludge to be used for the initiation, and able to reach stable operation state while granular sludge is not formed. In the first stage of anaerobic biological process, POME is pumped into a dosing tank 1 followed by a primary AnaEG™ (Fig. 4). Dosing tank is a holding tank that discharges effluent at a rate required by treatment processes. At the same time, the dosing tank also adjusts the pH of POME to 7 (neutral). The primary AnaEG™ is used to digest the high organic content of POME before degradation process in a secondary AnaEG™.

Dosing tank 1 Primary AnaEG Dosing tank 2 Secondary

Alkaline

Fig.4 Schematic process flow diagram of anaerobic biological process This system can be operated stably at 5-20 kg COD/m³.d, with an organic matter removal rate of 90% in wastewater treated. A detailed write up on the procedures of anaerobic treatment of organic wastewater in AnaEG™ can be obtained in the previous patent. b. BioAX ^{1 M} (for aerobic treatment of POME)

The BioAX system has also been patented (ZL 02 1 57780.3; PCT/MY2011/000046). It is an advanced aerobic system, similar to the attached growth process, which is faster and more efficient than the conventional activated sludge process. It has been successfully used for treatment of domestic waste and various types of industrial organic waste. BioAX™ is also the world's first high efficiency bio-membrane technology complete device which allows treated water to reach the requirements for reuse water.

Unlike conventional activated sludge process, BioAX does not require returned sludge. This has significantly simplified the operation process of the aerobic treatment plant. The technology has substantially reduces the sludge quantity and thus reduces the sludge handling cost, and the land area occupied by other conventional wastewater treatment plants. BioAX™ uses highly efficient microbial species to treat the clarified effluent through aerobic process whereby further degradation of organic matters will take place. It has specially designed plastic packing which contains high concentration of microorganisms used for the attached growth process where the microbial biomass (sludge) grows on the media and the effluent passes over its surface. Packing is installed at the aeration tank to improve the removal of organic matters in wastewater. The special designed aeration system ensures proper flow of wastewater in the aeration tank without short-circuiting. Besides that, this technology has a sensor at the discharge point to constantly monitor treated wastewater not exceeding the required BOD level.

In the first stage of aerobic process, the POME was coagulated and flocculated by dosing selected chemicals (polyacrylamide and polyaluminium chloride) through a pipeline mixer between a pump and the Nano-DAF (nano air flotation unit) to remove all the water insoluble SS, solids, residue oil, color, etc., including some soluble toxic components (e.g. trace elements - Cu, Mn, Zn, Fe) (Fig. 5). This DAF pre-treatment serves as an important basis for subsequent hydrolysis, acidification and aerobic treatment as some components that cannot be decomposed by biological means will be removed partially in the pre-treatment. As a result, its content in the final discharge will be greatly reduced before it enters BioAX™ for further aerobic treatment.

Buffer tank

Fig. 5 Schematic process flow diagram of aerobic biological process

The final stage in the secondary treatment is to remove the biological floe or filter the unwanted materials through a membrane bioreactor (MBR) and to produce effluent containing low levels of organic material and suspended matter. iii. Membrane Separation/Reclamation

In the process of reclamation via membrane separation, effluent undergoes a string of filtering system via safety filter, UF, fine filter and RO (Fig. 6). The purpose of this stage is to provide a final treatment to further polish and improve the effluent quality (Table 1).

Fig.6 Schematic process flow diagram of reclamation process

After clarification in the second clarifier, macromolecule such as SS will be removed through UF system before desalination (removal of salt ions) and de-colorization by RO. At the same time, natural pigment and liquid potash fertilizer will be recovered. Fine filter is to further clean unexpected small amount of particles and granules (impurities). Through this series of treatment, dual reuse of water is achieved: filtrate as boiler water; concentrate enriches the residual potash and sodium for use as fertilizer in the oil palm plantation.

TABLE 1: THE QUALITY OF PALM OIL MILL EFFLEUNT (POME) AFTER MEMBRANE SEPARATION

Parameter After biological treatment UF permeate RO permeate

COD (ppm) 774.9 701.1 ND

BODs (ppm) 20.0 < 20.0 ND

Turbidity (NTU) 111.0 0.8 0.4 SS (ppm) 289.6 ND ND iv. Sludge /Treated POME Recovery as Biofertilizer

The treated sludge can be recovered from the pre-treatment and AnaEG system, and piped and condensed in sludge tank (Fig. 7). Some of the characteristics of the raw POME and treated sludge tabulated in Table 2 shows that these sludge have good fertilizer values. Studies show that the application of organic fertilizers derived from the treated sludge enhances the fertility of the soil much better and more significant compared to the fertilizer derived from raw POME. This is supported by the fact that organic fertilizer derived from treated effluent contains higher NPK (nitrogen, phosphorus, potassium) value compared to the untreated ones. The sludge is pumped from the sludge tank and then dewatered using the sludge frame filter press to remove excess water content. Post-treatment of dewatered sludge is subjected to client's decisions.

Sludge Sludge Dewatered sludge Bio-fertilizer plant

Fig.7 Schematic process flow diagram of sludge disposal process

TABLE 2 CHARACTERISTICS OF UNTREATED AND TREATED PALM OIL MILL EFFLUENT (POME)

v. Biogas Capturing and Utilisation

The biogas produced via anaerobic digestion is rich in methane that can be used to generate electricity or flared to reduce GHG emissions into the atmosphere. The first option is adopted - to treat biogas using Fe₂0₃ in a biogas purifier for H₂S, C0₂ and moisture removal, after which the biogas is channeled to a biogas generator to produce electricity (Fig. 8).

AnaEG Water lute Biogas Purifier Generator

Fig. 8 Schematic process flow diagram of biogas utilization process

Following is a description by way of pilot plant assessment of the zero discharge POME treatment system integrated with pre-treatment, biological processes and membrane separation units which has been installed at the MPOB Experimental Palm Oil Mill (POMTEC, Labu). The performance of the pilot-scale treatment plant in treating POME was conducted for a period of more than 13 months (October 2010 - now). The five- tonne per hour pilot plant has been running at 3 t/hr for 20 hours per day that generates biogas at an expected rate of 150 m / hour.

The quality of POME at each stage of the different treatment is as shown in Table 3. With these treatments, the physical appearance of POME at various different stages of treatment can be obtained as shown in Fig. 9.

TABLE 3: CHARACTERISTICS OF PALM OIL MILL EFFLEUNT (POME) WASTEWATER OBTAINED AT EACH STAGE OF DIFFERENT TREATMENT

Avg. Avg.

Sampling Point Avg. COD Avg. BOD

pH TSS O&G (ppm) (ppm)

(ppm) (ppm)

Raw POME 75104.2 27500 3.85 - 5.04 37087.4 12581.8

Oil Separation 71464.4 25600 3.86 - 4.38 32673.2 7895.0 Tank

EQ Tank 63725.0 24000 3.81 - 4.8 29529.4

Dosing Tank 45796.1 20000 3.85 - 6.72 24591.0

AnaEGl 2764.4 800-1000 6.7 - 8.09 12032.8

AnaEG2. 2780.0 800-1000 6.86 - 8.34 11115.2

Nano Air Flotation 800-1000 7.02 - 7.36 14770.7

3125.1

Inlet

Nano Air Flotation 200-300 7.15 - 7.69 1044.5

2478.7

Outlet

BioAX 717.6 20-30 8.03 - 8.76 /

MBR 369.9 <20 8.59 - 8.62 66.2 UF 327.7 ND 8.59 - 8.63 /

RO 7.0 ND 7.4 - 7.7 1 7- :_f p->.,

¾

RAW RO ^■

I COD 7S,^QOOPP^m COD: Oppm _|'

BOD z .ooopp"¹ BOD: Oppm . I SI

Fig. 9 Quality of palm oil mill effluent (POME) wastewater after various treatments It was found that the percentage removal of COD and BOD in the anaerobic treatment using this developed zero discharge treatment technology is 94% and 96.5%, and after membrane treatment COD and BOD is almost not detectable (Table 4).

TABLE 4 REMOVAL OF BOD, COD, TSS and O&G AT ALL STAGES

The results of the assessment thus far show that the AnaEG produces biogas amounting to 52.7 m³/hr (Table 5) with a biogas production rate of 21-25 m³ biogas/m³ POME; and the biogas produced has compositions of 65-70% CH₄, 25-30% of C0₂ and 200-1500 ppm of H₂S. The removal of H₂S is ~ 70%.

TABLE 5 EVALUATION OF PERFORMANCE OF ANAEG

With the above anticipated performance for the zero discharge POME treatment plant, it is highly evident that the plant has an ability to produce biogas, reduce water discharge to BOD 20 ppm, recover sludge as fertilizer and recycle treated water as boiler feed water, but further fine-tuning and adjustment to the plant for full capacity operation is to be accomplished to achieve the zero discharge target. It is envisaged that a zero discharge POME treatment can be implemented in palm oil mills using the principles and concepts of this invention as shown (Fig. 10).

DOE standard

(monitored by

sensor) he proposed zero discharge palm oil mill effluent (POME) treatment plant

Claims

1. A zero discharge treatment technology in handling a palm oil milling waste; comprises the following steps:

(i) pre-treatment;

(ii) biological treatment; and

(iii) membrane separation.

2. The technology according to claim 1 wherein said palm oil milling waste used is POME.

3. The technology according to claim 1, where the following features will be demonstrated in a zero discharge POME treatment plant:

(i) zero discharge of POME;

(ii) biogas production and utilization as a form of renewable energy;

(iii) final discharge of POME BOD 20 ppm or below;

(iv) recovering sludge/dewatered sludge as biofertilizer with high K content; and

(v) recycling of the treated water for boiler use.

4. The technology according to claim 1, where the system final goal is to obtain three main products - biogas rich in methane, treated water and biofertilizer high in K.

5. The technology according to claim 1, wherein the biological treatment of POME using AnaEG & BioAX can produce final discharge reaching BOD 20 ppm as required by Department of Environmental (DOE) and COD 50 ppm and removal of NH₄-N can be accomplished.

6. A distinguished feature of the technology as claimed in claim 1, wherein while achieving quality recycled water as good as drinking water for recycling purpose, a zero discharge POME treatment plant has to compromise on having an average biogas production due to the more severe pre-treatment in removal of COD, BOD and SS (so that the wastewater will be easily treated in the later part).

7. Other advantages in the zero discharge POME treatment system is (1) a very low sludge content of less than 10% as compared to activated sludge, (2) the bacteria for ammonia removal do not have to be replenished, thus saving very high chemical costs in ammonia removal and (3) low operation cost.

8. The plant as claimed in claim 6, wherein the design of the zero discharge POME treatment plant can accommodate and be upgraded in such to have maximize biogas production if the focus is on biogas.

9. The plant as claimed in claim 6, wherein this concept is highly relevant and applicable in areas where water is of shortage, and for future needs to reduce water consumption due to climate change, global warming and the need to have water footprinting assessment as one of the environmental indicators in assessing the environmental impact using a technology.

10. The technology according to claim 3, wherein a zero emission of POME into atmosphere can be accomplished through the proposed advanced zero discharge treatment system of POME. Therefore no GHG emitted into the atmosphere.

11. The technology according to claim 3, wherein no discharge of POME wastewater into a watercourse which will pollute the environment.

12. The technology according to claim 3, wherein a production of biogas from POME as a renewable energy is achievable (desirable target: 150 m³/hr for a 5 t/hr pilot plant).

13. The technology according to claim 3, the achieved biogas production rate is 21 -25 m³ biogas/m³ POME and the biogas compositions is 65-70% CH₄, 25-30% of C0₂ and 200-1500 ppm of H₂S.

14. The technology according to claim 3, wherein the biogas plant efficiency for a 30 t/hr and 60 t/hhr palm oil mill based on plant performance as claimed in claim 12 is 14-16 and 28-32 MWh/day or 0.7 - 0.8 and 1.4 - 1.6 MW electricity potential, respectively.

15. The biogas as claimed in claim 12, wherein it is produced, captured and used as a boiler fuel and for generation of electricity.

16. The biogas as claimed in claim 15, wherein a biogas purification unit is used to remove impurities in biogas.

17. The said biogas purification unit as claimed in claim 16, uses Fe₂0₃ for H₂S removal, after which the biogas is channeled to a gas engine to produce electricity.

18. The said biogas purification unit as claimed in claim 16 has a H₂S removal rate of -70% based on pilot plant performance installed at MPOB Experimental Palm Oil Mill, POMTEC, Labu.

19. The technology according to claim 12, wherein the produced biogas can replace palm kernel shell (PKS) previously used as a fuel for boiler to generate steam and or electricity. The said PKS can be sold at premium price for a fuel for other purposes.

20. The technology according to claim 1 wherein a pre-treatment system is adopted to treat POME before it is subjected to anaerobic treatment.

21. The technology according to claim 20, wherein the pre-treatment process in this system has the capability to recover residual oil

22. The technology according to claim 20, wherein the residual oil recovered can be sold as a technical grade oil to generate revenue.

23. The technology as claimed in claim 3, wherein sludge from both the pre-treatment system and anaerobic treatment can be recovered and reused as a biofertilizer due to the high content of potash (K).

24. The technology as claimed in claim 1 wherein the reclamation system using membrane separation uses membrane bioreactor (MBR), ultra filtration (EF) and reverse osmosis (RO) to treat and recover the treated water.

25. The technology as claimed in claim 24, wherein the series of membrane filtration remove some of the macromolecule and inorganic salt in POME to obtain clean/pure water.

26. The technology as claimed in claim 24, some natural pigment and liquid potash fertilizer can also be recovered at the same time. The RO concentrate enrich the residual potash for use as fertilizer in the plantation.

27. The treated water (clean water/RO water) as claimed in claim 25 can be recycling as boiler feed use to reduce corrosion arises from the use of existing technology in the boiler.

28. The design of the zero discharge POME treatment technology can be separated and operated in individual unit to suit customers' requirement with desired optimum performance accomplished.

29. The vertical enclosed tank systems used in the zero discharge POME treatment technology requires only 1/3 of the land and the cost required by open ponding system. As a result, this integrated system can be increased to double the capacity without requiring additional land, thus occupies a smaller footprint and resulted in lower operating cost compared to other existing systems.

30. The implementation of a zero discharge POME treatment as claimed in claim 1 is eligible for incentives offered by the Clean Development Mechanism (CDM) programme under the United Nations Framework Convention on Climate change (UNFCCC).

31. This system can also assist millers to qualify for Roundtable on Sustainable Palm Oil (RSPO) certification.