Enhancement of Palm Oil Refinery Waste

Industrial Crops and Products 49 (2013) 775 781

Contents lists available at SciVerse ScienceDirect

Industrial Crops and Products

journa l h om epage: www.elsev ier .com

Enhanc nt into bio ro

Soh Khea KahYuen Maa Malaysian Pab MPV Technoloc School of Chem aan M

a r t i c

Article history:Received 26 MReceived in reAccepted 13 Ju

Keywords:Spent bleachinCompostingSoil amendmentBio organic fertilizerSlow release propertyPlant growth

from nly dt has ilizer.E ha

equatty (CEcant

kangkung (Ipomoea aquatic) and groundnut magenta with 2-fold increases (3560%) on average in freshand dry matters production.

2013 Published by Elsevier B.V.

1. Introdu

Pre-treawhich invospent bleacder and itsdepending clay (represeluting basiBleaching eodour-causmated that was utilizedwide produ2004).

SBE is ahigh percenet al., 2006feeds, land practiced. Cposal at lan

CorresponE-mail add

0926-6690/$ http://dx.doi.oction

tment of crude palm oil (CPO) during a rening processlves degumming and bleaching, generates plentiful ofhing earth (SBE). Bleaching earth is a very ne pow-

main component is silicon dioxide (57% and moreon the type). It is prepared by treating montmorilloniteented by Al2O34SiO2nH2O) with mineral acids and byc components such as aluminium, iron and magnesium.arth has been used to absorb dark colour matters anding substances in crude oil and vegetable oil. It is esti-about 600,000 metric tonnes or more of bleaching earth

worldwide in the rening process based on the world-ction of more than 60 million tonnes of oils (Park et al.,

discarded palm oil renery (POR) waste containing atage of residual oil (2040%) (Aziz et al., 2001; Loh). Disposal of SBE by incineration, inclusion in animallling method or concrete manufacturing is generallyurrently in Malaysia, the most common practice is dis-dlls causing re and pollution hazards due to the

ding author. Tel.: +60 387694456/9253428; fax: +60 389263827.ress: [email protected] (S.K. Loh).

degradation of the residual oil in it, and the associated green-house gas (GHG) emissions upon its disposal. In Japan, SBE hasbeen incinerated for cement manufacturing but there is difcultyin maintaining good cement quality due to the high concentrationof oil in SBE (Park et al., 2004). In the near future, incineration orlandll disposal will probably become impossible due to a stricterenvironmental regulatory restriction, lack of new dump sites andmost importantly, the release of GHG to the atmosphere at landlls.

The residual oil in SBE should ideally be recovered and re-usedfor industrial applications in order to reduce cost in oil processing.Adding value to the recovered residual oil is among the manypossible approaches to resolving the issue e.g. as feedstock forbiofuels (Loh et al., 2006), biolubricants (Loh et al., 2007), indus-trial grade oleochemicals (Chanrai and Burde, 2004) and animalfeeds (Damodaran, 2008). Apparently, the de-oiled SBE withoutany known applications was destined at landll as required bythe local authorities. SBE without residual oil recovery can alsobe used as feed material (Ng et al., 2006). Other attempts onSBE utilization include regenerating SBE as adsorbents (Cheah andSiew, 2004), fermenting oil-containing SBE to produce riboavinfor use in medicine, food and fodder industries and recoveringriboavin-free SBE-based soil conditioner without much evidencegiven (Park et al., 2004). In recent years, waste clay and recycledbentonite in either their original forms, or co-composted with ricehusk, rice husk ashes, chicken litter and other benecial biomass

see front matter 2013 Published by Elsevier B.V.rg/10.1016/j.indcrop.2013.06.016ement of palm oil renery waste Spe organic fertilizer and their effects on c

ng Loha,, Stephen Jamesb, Muzzamil Ngatimana,y Chooa, Weng Soon Lima

lm Oil Board, P.O. Box 10620, 50720 Kuala Lumpur, Malaysiagies (Pasir Gudang) Sdn. Bhd, Malaysiaical Science and Food Technology, Faculty of Science & Technology, Universiti Kebangs

l e i n f o

arch 2013vised form 10 June 2013ne 2013

g earth

a b s t r a c t

Spent bleaching earth (SBE) derived physically rened palm oil is commoled to environmental degradation buutilization of SBE as a bio organic fertoil milling by-products. Composted SBand microbial rejuvenation due to adcarbon (OC); cation exchange capacitrials carried out indicate highly signi/ locate / indcrop

bleaching earth (SBE)p biomass growth

Yein Cheonga,c,

alaysia, 43600 UKM, Bangi, Selangor, Malaysia

the degumming and bleaching of crude palm oil (CPO) fromisposed off at landlls at a high cost. Its disposal has so farnot been addressed. This study demonstrates the innovative

The SBE was co-composted with some agricultural and palms a positive impact on soil physical attributes for plant growthe amounts of benecial mineral elements; improved organicC); water-holding capacity and C:N ratio. The pot and eld

increases in the productivity of okra (Abelmoschus esculentus),

776 S.K. Loh et al. / Industrial Crops and Products 49 (2013) 775 781

or agriculture by-products as a soil amendment was extensivelyresearched (Arias-Estvez et al., 2007; Croker et al., 2004; Hoet al., 2010; Soda et al., 2005; Wang et al., 2010). For exam-ple, an organic-rich bentonite-based waste particularly generatedfrom the wfacilitate sobial rejuven(Nvoa-Muface can alsleaching of et al., 2011;

To date,because theproblem. Thon 100% recby co-compby-productgood characof crop protilizer applearth. It proproblems c

2. Method

2.1. Materi

Bulk supregular basiacid-activatconditions iwas dischardedicated btransfer systo haulage t

2.2. Pilot se

A pilot Spilot plant wposting sys(width) 118 24 6

2.3. Formulfertilizer

The SBE substances rening prphase with(40%) i.e.(POME) anding ratio ofnitrogenpproduct forvia differen3050 C infacilitate aemicrobial gregularly fo

2.4. Pelletiz

The SBEletized via

pelletizing, and separation, drying and packing. The bio materialswere fed manually to the pelletizer which was equipped with diesof 2 sizes (4 and 6 mm) rotated by a belt system. The pelletizing pro-cess was conducted at an ambient temperature to

S.K. Loh et al. / Industrial Crops and Products 49 (2013) 775 781 777

Table 1Fertilizer value (NPK content) of various bio-based materials.

Component N (%) P (%)

Spent bleaching earth (SBE) 0.060.71 2.012.3Oil palm tru 7 Empty fruit 3 Oil palm fron 3 Mesocarp b 0 Palm oil mil 5 Chicken litte 2

planted. Thlength, numformance awere condu3-month trperiods. Thedry weightand used in

2.7. Field ev

A big scaPertanian Nan agriculttested cropThe sandy lcation rate was used thDepartmenments speciselected raformance inSBE-based bthe fruits wconducted. weights usiment.

2.8. Statisti

A statistof treatmenperformanc

3. Results

Bio fertilcentrated mexcluded thSBE was foupared to vaPOME, EFB,products (ein any bio fbefore comrials which SBE containbe low, thusapplicationlimiting bio

3.1. Charac

Bleachinural clay h

risticite.

terist

oistu% sus

ical co

5.2 4.32 1.011.7 3.9 2.510.4 0.08 1.701.2 0.96 2.28NA 0.10 0.05NA 0.90 0.30NA 4.87 0.05

o Supreme 1B supplied by Taiko Clay Marketing Sdn. Bhd. (2006).as Zeolite, national fertilizer for Bionas Bio-diesel Project.applicable.

ristics of residual oil of spent bleaching earth (SBE).

teristics SBE

al oil characteristicstty acids, FFA (%) 12.6de value, PV (meq/kg) 3.4horus, P (mg/kg) 18.7e (mg/kg) 1.24r, Cu (mg/kg) 0.38tene (mg/kg) 6itamin E (mg/kg) 38.8

acid compositions, FAC (wt% as methyl esters) 1.0 44.4 4.7

39.4 10.5

etically it mimics zeolite in many ways. It has essential min-ments (N, P, K Table 1; Ca, Mg, Zn, Fe, Mn, Cu, Ti Table 2)necial elements (Si, Na Table 2) for potential use as applement for plant growth. The physicochemical properties

after the bleaching process in oil renery have not alteredompared to the fresh earth (Table 2). Furthermore SBE fromsorbs about 6 to 18% of residual CPO mainly palm-based fattyanging from C14 to C18 which also contains important nutri-ments and phytonutrients (e.g. carotene, vitamin E, Table 3).er the earth and the oil of SBE are relevant candidates in pro-nks (OPT) 0.19 0.0bunches (EFB) 0.33 0.0ds (OPF) 0.55 0.0re 0.80 0.1

l efuent (POME-treated) 4.68 1.2r 1.08 2.2

e physical parameters observed were plant height, rootber of leaf, size of leaf and number of fruit. Two per-

nd efcacy assessments at different cultivation periodcted i.e. in a month of cultivation and after a completeial. The plants were harvested after the set cultivation

physical parameters of the plant (fresh weight and or of the total biomass, shoot and root) were measured

a statistical analysis.

aluation and efcacy test

le eld trial was conducted in cooperation with Jabatanegeri Perak at Kompleks Pertanian Titi Gantung underural programme by the Ministry of Agriculture. The

was groundnut var. magenta on 0.5 ha cultivation land.oam soil used was loose with pH of 5.76.5. An appli-of 250 kg ha1 of the SBE-based bio organic fertilizerroughout the trial. This rate was recommended by thet as per the standard used based on the NPK require-cally for planting magenta groundnut. Ten plants werendomly for the monitoring of the plant growth per-

every fortnight starting from the application of theio organic fertilizer. At the end of the cropping phase,ere harvested and measurement of their fresh weightsThe results were compared with that of the fresh fruitng commercial fertilizer commonly used by the Depart-

cal analysis

ical analysis tool, t-test was used to analyze signicancet of SBE-based bio organic fertilizer on plant growthe.

and discussion

izer production in the oil palm industry has so far con-ainly on the by-products from palm oil mills but hase renery waste (namely SBE) discharged by the PORs.nd to contain a fairly adequate quantity of NPK com-

rious other bio materials such as oil palm biomass (e.g. OPT and oil palm frond or OPF) and agricultural by-.g. chicken litter) (Table 1), which is essentially requiredertilizer production. The initial C:N ratio of 290 in SBEposting was far too high compared to other bio mate-could decompose readily in the eld as mulch. Thoughed a high C with limited N, the bioavailability of C could

the decomposition of SBE being slow. Hence, the direct

Table 2Characteand zeol

Charac

Free mpH (20

ChemSiO2Al2O3Fe2O3MgO CaO Na2OK2O MnO2TiO2P2O5

a Taikb Bion

NA: not

Table 3Characte

Charac

ResiduFree faPeroxiPhospIron, FCoppe-CaroTotal v

Fatty C14:0C16:0C18:0C18:1C18:2

hypotheral eleand besoil suof SBEmuch cPOR adacids rent eleTogeth of SBE to soil would have caused a detrimental effect inavailability of soil N for plant growth.

teristics of SBE

g earth is montmorillonite and bentonite-based nat-aving similar characteristics as that of zeolite, thus

moting plarejuvenatioof these nuP2O5 has a pN and Mg Hence, the overall planK (%) C:N

6 0.270.84 2901.21 1551.59 50942.00 48610.50 575.16 82.25 7

s of freshly manufactured bleaching earth, spent bleaching earth (SBE)

ics aFresh bleaching earth SBE bZeolite

re (%) 10.5 01.8 6.9pension) 4.6 4.55.3 6.07.0

mposition by ash (% oxides by wt)60.4 56.9 7111.5 9.24 119.3 8.27 1.61nt growth and providing nutrients for microorganismn. Regardless of the concentration and bioavailabilitytrients in SBE, it is well established that the presence ofositive impact on the growth of owers and fruits, whileaffect leaves growth and K catalyzes photosynthesis.presence of NPK is required in any form of fertilizer fort growth. Based on the analyses, SBE has almost all the


Table 4Characteristics of spent bleaching earth (SBE) before and after composting.

Fertilizer characteristic SBE SBE-based bio organic Mineral soil Soil: SBE-based bio organic (50:50)

Water holding capacity, ml/100 g 5.76.5 1320 14 137140Organic carbon (%) 7.06 15.8117.23 1215 11.85Organic matter content (%) 12.17 27.2630.04 1530 20.43Cation exchange capacity, cmol/kg 8.03 31.536.0 29.2 3239C:N 290 921 2535 32pH 4.55.2 5.46.5 5.56.5 5.89

nutrients required for plant growth although not in an optimizedlevel.

Another important aspect is that SBE contains Si and Al (Table 2)that strengthens the ability of soil to hold nutrients. Due to the iso-morphous substitution of Si4+ by Al3+ in the mineral structure ofthe earth and the containment of the negatively charged organicmatter in it, SBE has a net negative surface charge. The negativecharge associated with isomorphous substitution is considered per-manent, that is, the charge does not change with pH changes. Inthis case, when SBE is associated with soil, it enhances soil char-acteristics and strengthens the negativity of soil surface charges inexchanging the positively charged ions of common nutrients suchas Ca2+, Mg2+, K+, Fe2+, Na+, Mn2+, Zn2+, Cu2+ and Ni2+. This furthersupports the increases of CEC in the presence of increased organiccarbon (OC) in composted SBE.

Besides, a total pore volume of 0.165 cm3 g1 for the SBE isindicative of a material that is not as good an adsorbent as activatedcarbon (0.459 cm3 g1) but sufces to loosely bind the nutrients andrelease them slowly when needed by the crops. It shows adequatesorption/desorption capability. Once it is enhanced or composted,it increasescapacity of at the momSBE was ind

3.2. SBE-ba

Organic occurring minclude mi

rock phosphate which is naturally occurring too. Organic fertilizeris produced naturally or via natural biological processes such ascomposting. The majority of nitrogen supplying organic fertilizerscontain insoluble nitrogen and act as a slow-release fertilizer. SBEwhich is a naturally occurring montmorillonite/bentonite clay con-taining mineral deposits that is mined and physically treated intopowder form without using chemicals. Hence, they can be consid-ered organic. By co-composting SBE with other naturally occurringorganic materials such as agricultural by-products and oil palmbiomass, the composted nished products can still be consideredas organic fertilizers.

3.3. Composting process

A signicant problem in the reuse of SBE from vegetable oilprocessing is its hydrophobic nature in the presence of residualoil on its surfaces as well as its acidic nature. The average pHof the 1:5 extract SBE solutions (20% suspension) and the water-holding capacity of SBE were 4.9 and 6.1 mL/100 g, respectively.Through the co-composting of SBE with chicken litter and palm oil

by-alterpos

incralkalg prosencs as ty, bining

Fig. 1. Compa*Data obtained**Fertilizer spe water holding capacity, porosity and the adsorptionnutrients. Unfortunately, there is not enough evidenceent to show that the structure and texture of compostedeed improved.

sed bio organic fertilizer

fertilizers are naturally occurring fertilizers or naturallyineral deposits. In practice, organic fertilizers usually

neral-based fertilizers as well, such as greensand or

millingcantly co-comThe pHto the postinthe preprocescapaciin retarison of nutrient levels (%) between spent bleaching earth (SBE)-based bio organic and ot from commercially available organic fertilizer packaging labels.cication by Ministry of Agriculture, Malaysia.products, the chemical attributes of SBE were signi-ed. The average pH and water-holding capacity of theted materials were 6.1 and 16.5 mL/100 g, respectively.eased with the addition of co-composted material dueine nature and alkalinity generated through the com-cess. The hydrophobic nature of SBE was high due toe of adsorbed residual oil associated with the bleachingwas evidenced by the measurement of water-holdingut the composted SBE showed an increased capacity

water, thus declining in the hydrophobic nature. Ither commercial organic fertilizers (A, B, C).


was evident that this was attributed in part to an active micro-bial rejuvenation during the composting in consuming the residualoil. The increase in water-holding capacity also was indicative ofan increase in total porosity.

3.4. Characteristics of SBE-based bio organic fertilizer

The novel composting method has the ability to modify themorphology of the clay structure in SBE, in remedying and improv-ing other chemical attributes besides eliminating the acidic andhydrophobic nature of the earth. The resulting SBE has beentransformed into an effective bio organic material with improvedorganic carbon (OC) content from 7.1 to 16.5%, the CEC from 8.0 to33.8 cmol/kg, the water-holding capacity from 6.1 to 16.5 ml/100 gand the C:N ratio from 290 to 921. The OC increased due to theresidual oil in SBE and the high OC content of the co-compostedmaterials. Most of the degradable organic matter was decomposedand replenished. An increase in OC after composting would havecontributed to the observed increase in CEC, thereby enhancing thenutrient supplying capacity of the bio organic fertilizer made. Sur-prisingly, the C:N ratio improved tremendously after composting.This showed that the microorganisms present in SBE, 8000 colonialform unit (CFU) in 10 mL of diluted SBE supernatant, had utilizedthe residual oil and the organic matter readily available in SBE ascarbon source to manipulate and transform SBE into a suitable basematerial facilitating microbial activities.

When SBE is associated with soil, the CEC of soil will be improved(Table 4) by weakly binding the exchangeable cations onto thenegatively charged soil surface via electrostatic forces. The CECof the mineral soil mixed with composted SBE at SBE:soil ratio of50:50 has increased from its original 8 cmol per kg to 3239 cmolper kg. This is indicative of an increase in organic matter (sourceof negative electrostatic sites), thus an increase in ability of the

Fig. 2. Fresh matter production (total biomass, shoot and root) of kangkung in a pottrial after a month of cultivation with composted spent bleaching earth (SBE).

soil to exchange, attract and retain nutrient elements from SBEin a loosely bound bonding. This will prevent nutrient loss vialeaching by allowing plants to extract them from the soil via swap-ping them with H+.

The high CEC is also indicative of greater water-holding capacityand slow release of water/nutrients once it is mixed and acti-vated with soil. It holds 20 mL of water per 100 g of SBE whilesoil mixed with composted SBE (50:50) can hold up to 140 mL ofwater (Table 4). The resulting bio organic material thus has a slowrelease property in managing the controlled-released efciency ofnutrients and water in soilfertilizer interaction. This is because thetransformed SBE tends to entrap/encapsulate volatile nutrient ele-ments (such as N) and then releases them slowly into the soil it isapplied to. An optimal C:N ratio ranged 921 in SBE-formulated bioorganic fertilizer was achieved approaching C:N ratio for adequatemicrobial soil function, thus shows evident that it contributes to

Fig. 3. Compa m diameter and (d) fruit size] of okra in different fertilizer treatment (A)Control, (B) ch ial.rison of the plant growth performance [(a) height of plant, (b) size of leaf, (c) steicken litter and (C) composted spent bleaching earth (SBE), after a 3-month eld tr


Table 5Example of results of a eld trial on groundnut var. magenta using composted spentbleaching earth (SBE).

Parameter [per plot (0.5 ha)basis]

Composted SBE-based Standard fertilizer

Average planNo. of pods1 pod 2 pods 3 pods % of 2 podsAverage fres

plant nutritother commdecomposit

The SBEgive good bnatural bin

3.5. Perform

Small sckangkung aa bio organ

3.5.1. IpomThe t-tes

and the selafter a mongrowth of tand clearlyfresh weighthe plants ttreatment (treated witleaves and

3.5.2. AbelmIt was ob

signicantlthe stem dcompared thad healthi

The t-tesand the seletivation witon the oveshowed an otion for thand for thesame treatmdemonstratleaf (p = 0.7evidence (pweights whof okra for yield and 37

The obsand efcacment (60%It was obsebio organic population clear leaf bo

resh and dry matters production of the selected harvested biomass of okra trial at (a) a month and (b) 3 month of cultivation with composted spentg earth (SBE).

ce, the pot and eld trials that have been conducted so fard that composted SBE-based bio organic fertilizer enhancestility, promotes rapid root and plant growth, and improvesality while increasing crop productivity and yield. Currently,rials are under way to investigate the effects of this organicer on oil palm productivity. Nevertheless, it would be oft to focus on incorporating SBE with other wastes gener-r potential application on a wide range of other crops in the

clusion

ough composting SBE with agricultural and palm oil millingducts, the physicochemical properties such as the acid reac-and hydrophobic nature of the composted SBE improvedbio organic fertilizer package

t height (cm) 61.3 100.1

195 110351 226

3 264 67

h weight (g) 1201.2 756.2

ion when applied to the soil, and that it is superior toercial organic fertilizers (Fig. 1) in terms of biologicalion of organic residue and bioavailability of C, N and P.-based bio organic fertilizer is favourably pelletized toinding effect to the fertilizer due to the presence ofder vis--vis the residual oil in SBE.

ance of pot and eld trials

ale pot assays was conducted on (i) I. aquatic ornd (ii) A. esculentus or okra, using composted SBE asic fertilizer.

oea aquatic or kangkungt of the fresh weights of the total biomass (whole plant)ected parts of the harvested biomass (shoot and root)th of cultivation showed, on average, a more signicanthe plants shoot (p = 0.02) than that of its root (p = 0.72)

demonstrating an overall 50% increase in kangkungt production (m = 18.1, SD = 2.0, t(3) = 3.2, p = 0.018) forreated with composted SBE compared to that withoutm = 12.5, SD = 0.5) (Fig. 2). It was observed that kangkungh composted SBE has a better germination rate, morehealthier growth compared to the control.

oschus esculentus or okraserved that okra treated with composted SBE improvedy in the plant height (Fig. 3a), the size of the leaf (Fig. 3b),iameter (Fig. 3c), the yield and the fruit size (Fig. 3d)o that of the plants without treatment. The treated okraer growth too.t of the fresh weights of the total biomass (whole plant)cted parts of the harvested biomass after a month of cul-h the composted SBE showed signicant improvementsrall plant growth and fruit yield (Fig. 4a). The resultsverall 2- to 3-fold increase in okra fresh weight produc-e total biomass (m = 19.8, SD = 1.7, t(4) = 2.8, p = 0.0003)

fruit (m = 16.1, SD = 1.5, t(3) = 3.2, p = 0.003). Under theent and after a complete 3-month trial, the okra plants

ed insignicant growth in both the root (p = 0.18) and0) in the dry weight basis. However, there is enough

= 0.01 and 0.04, respectively for the fresh and dry fruitich are < = 0.05) to show that the yield productivity

Fig. 4. Fin a potbleachin

Henshowesoil fercrop qusome tfertilizinteresated fofuture.

4. Con

Thrby-protivity this treatment increased signicantly i.e. 60% for fresh% for dry yield, respectively (Fig. 4b).

ervations conducted on the big scale eld evaluationy testing showed that there was a signicant incre-) in the fresh weight of groundnut magenta (Table 5).rved that the plot treated with composted SBE-basedfertilizer in groundnut magenta cultivation showed lessof wild grass as well as having brighter leaf colour andnes.

drastically.izer properand OC conact as an esoilfertilizconducted productivitcompost caof crops. The resulting compost exhibited some enhanced fertil-ties such as the C:N ratio, water-holding capacity, CECtent that was able to rejuvenate degraded soil, and tofcient water/nutrients controlled release fertilizer iner interaction. Results from the pot assays and eld trialfurther revealed a signicant biomass growth and yieldy for the tested crops. In general, the developed SBEn be used as a bio organic fertilizer for a wide range


Acknowledgements

The authors thank the Director-General of Malaysian Palm OilBoard (MPOB) for nancial support, and for permission to publishthe ndings. The technical assistance provided by the staff of theEnergy and Environment Unit of MPOB is also deeply appreciated.

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Enhancement of palm oil refinery waste Spent bleaching earth (SBE) into bio organic fertilizer and their effects on crop...1 Introduction2 Methods2.1 Materials2.2 Pilot setup of a SBE recovery plant2.3 Formulation and production of SBE-based bio organic fertilizer2.4 Pelletization of SBE-based bio organic fertilizer2.5 Analyses2.6 Pot assay2.6.1 Ipomoea aquatic (kangkung)2.6.2 Abelmoschus esculentus (okra)

2.7 Field evaluation and efficacy test2.8 Statistical analysis

3 Results and discussion3.1 Characteristics of SBE3.2 SBE-based bio organic fertilizer3.3 Composting process3.4 Characteristics of SBE-based bio organic fertilizer3.5 Performance of pot and field trials3.5.1 Ipomoea aquatic or kangkung3.5.2 Abelmoschus esculentus or okra

4 ConclusionAcknowledgementsReferences

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Enhancement of Palm Oil Refinery Waste