ENGINEER - Vol. XXXX1, No. 04, pp. 50-65, 2008© The Institution of Engineers, Sri Lanka

Delta-D Initiated Microorganic Digestion of Saw Dustinto Organic Fertiliser - A Technically, Economically

and Environmentally Feasible Solution to the SawDust Problem in Sri Lanka

S A S Perera

Abstract: This paper, presents the results of a self financed research project, carried out by theauthor, to develop a method, to rapidly digest saw dust (SD) and convert it into Organic Fertilizer(OF). Since, it is well known that SD is extremely resistant to biodegradation by both aerobic andanaerobic micro organisms, the author studied the possibility of converting four types of SD, namely,Jack, Mahogany, Teak and Rubber into organic fertilizer, using a combination of Delta-D Technologyand composting by aerobic micro organic activity. The research was carried out during the periodAugust 2007 to May 2008, at No: 20, Gimpatha Road, Wattalpola, Panadura. During the first 3 months,the research carried out was on composting of pure SD with 40%, 45% and 50% moisture andcomposting of SD with similar moisture contents mixed with fish and vegetable market wastedigested using Delta-D. From December 2007, the suitability of the organic fertilizer produced wastested by applying to mature plants and tender plants of fruit varieties; Papaya, Guava, Mango andAmbarella and vegetable varieties ladies fingers, egg plant, capsicum, slender gourd, bitter gourdand long beans.

Delta-D Technology P-AS-4-5) is a patented process invented by the author to rapidly digest biomass intoorganic fertilizer. The novelty of the technology is that, a digestive fluid, called Delta-D, is used torapidly break down, cellulose, carbohydrates, oils, fats, proteins, resins and other components inbiomass, into simple molecules that can be absorbed by plants and other organisms, as food.

The results of the composting project clearly indicated that, samples of SD with only moisture did notundergo composting, while, samples with similar moisture contents, mixed with fish and vegetablemarket waste digested using Delta-D, underwent composting successfully within 2 months. Initialagricultural trials, commenced in December 2007 indicated that the organic fertilizer had positiveimpacts on the growth of all the species to which it was applied. The agricultural trials are continuingand the results will be published in the first quarter of 2009.

1. Introduction

Saw dust (SD) is a waste material produced insaw mills and wood based production plants.SD has become a major solid waste problem,since, at present, there is no technically,economically and environmentally viableprocess to use or dispose SD. As a result, SD iseither haphazardly burnt without energyrecovery or illegally dumped on land, inrivers, in lakes and in the ocean, where itremains undecayed for many years due to itsvery low biodegradability. When 1 ton of drySD is burnt, it produces 1.6 tons of COi, inaddition to smoke and other particulatematter,thereby significantly polluting the atmosphere.

Some SD produced in wood based productionplants is toxic due to chemical treatment of

sawn timber to prevent termite and microbialattack. The standard methods of chemicaltreatment are, Boron Treatment and Chrome-Copper-Arsenic (CCA) Treatment. CCA isextremely toxic and the saw dust producedshould be incinerated in a cement or lime kilnto prevent soil and ground watercontamination. CCA based SD cannot be usedfor composting or any other micro organicdisposal system, since, Chrome, Copper andArsenic are toxic to microorganisms.

Eng. S A S Perera, BASC(ChEng 2 fuel Science), CEng.,PEng(SL), FlE(Sri Lanka), MAlChE(USA), MlCliemE(UK),is a Senior Lecturer attached to the Department of Chemicaland Process Engineering of the University ofMoratuwa.

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2. Survey on Production of SD andUtilisation of SD in Moratuwa andI'nnadura

A Nurvey carried out by the author indicated,Ihiil, the daily production of SD in Moratuwartiul 1'anadura alone exceeds 200 tons per day.Tin- study also revealed that attempts made bymany companies to use SD as a source of fuelhave not been successful, due to the highmoisture content (greater than 30%) and thehigh resin and ash content. When SD isignited, after a few minutes, the flame getsextinguished, unless, a continuous stream ofair is passed through the bed of SD or the bedis stirred or fluidized. This requires the supplyof excess air, which dilutes the fluegas andlowers its temperature, causing unsatisfactoryheat transfer and carryover of ash, as well as,unburnt SD. Moreover, since, SD has a verylow density (around 200 kg/m3), unless it iscompressed into high density briquettes, itstransport over long distances is uneconomical.

The survey also revealed, that, attempts madeby many companies to use SD to manufactureparticle boards, such as, chip boards andmedium density fiber boards, have not beensuccessful, mainly due to the high cost ofimported adhesives, such as UreaFormaldehyde, Phenol Formaldehyde, PolyUrethane, Poly Styrene, Polyester and Epoxy,which makes locally manufactured productsnoncompetitive with imported products.

3. The Main Reasons for the Decisionto Produce Organic Fertiliser fromSaw Dust

Based on the above survey and a basictechnical, economical and environmentalevaluation of the various options available forthe use of SD, the author was of view, that, oneof the best low cost options was to convert SDinto organic fertilizer by composting, since, SDhas a high content of organic carbon (around44% of C), which is much higher than mostother types of solid wastes, such as,canteen/hotel/ waste (around 15% of C),slaughter house, fish and meat market waste(around 10% of C), and vegetable and fruitmarket waste (around 10% of C). Since, it iswell known that SD is extremely resistant tobiodegradation by both aerobic and anaerobicmicroorganisms; the author studied thepossibility of converting SD into organicfertilizer, using a combination of Delta-D

Technology and aerobic micro organiccomposting.

4. The Current Fertiliser Situation inSri Lanka and its Impact onAgriculture.

According to history, Sri Lanka was oncecalled the granary of east asia, since, Sri Lankawas not only self sufficient in rice, butexported the surplus to foreign countries.During those times, sustainable agriculturalpractices were used, where farmers usedorganic fertilizer, self produced fromagricultural and farm wastes, hence their costsof production were low. However, the presentsituation in Sri Lankan agriculture is that,imported chemical fertilizers are used atexorbitant costs since, Sri Lanka does noteither produce chemical fertiliser or organicfertilizer of good quality in large quantities.The present (June 2008) retail market pricesper metric ton (MT) of the three mostdemanded N, P, K, Mg fertilizers are, Urea -Rs. 100,000.00, Triple Super Phosphate (TSP) -Rs. 145,000.00 and Muriate of Potash (MOP) -Rs. 135,000.00, Kiesserite (MgSO4.H2O) - Rs.45,000.00. The prices of these fertilizers havemore than doubled during the past one yearand are expected to further increase with therising prices of crude oil. Although there is a60 million MT deposit Rock Phosphate atEppawela (ERP) in Sri Lanka, it cannot be usedas a substitute for TSP, due to the very lowsolubility. If the solubility of ERP can beincreased, its value will increase from Rs.9000.00 to Rs. 145,000.00 per MT. AlthoughDolomite (MgCOs.CaCOs) is abundant in SriLanka, it cannot be used as a Mg fertilizer, dueto very low solubility. If the solubility ofDolomite can be increased, its value willincrease from Rs. 1000.00 to Rs. 45,000.00 perMT.

Organic fertilizer manufactured from SD withDelta-D Technology^1-3-4-5) , will have highlevels of N,P,K and Mg, since N containingwastes are added and the solubility of locallyavailable ERP, Dolomite and Mica areincreased by Delta-D.

If SD based organic fertilizer of high N,P,K,Mg(i,3,4,5) can be produced in large quantities, theirwill be a ready demand for it and the localfarmers will be able to get their fertilizer at avery low cost. Moreover, the Government ofSri Lanka (GOSL) gives a massive ureafertilizer subsidy (Rs. 16 billion in 2007 and

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more than Rs. 35 billion) to farmers in SriLanka. Soil scientists have shown that morethan 75% of urea applied to soil gets washedaway due to its high solubility in water,contaminating ground water, rivers, lakes andother water bodies. Manufacturing largequantities of organic fertilizer and promotingit amongst farmers will be beneficial to allstake holders, due to savings in fertilizersubsidy, non pollution of water resources,cheap fertilizer and finally cheaper agriculturalcommodities to the people of Sri Lanka..

5. Some Important Characteristics ofSaw Dust

SD consists of fine particles of wood, producedas a result of, sawing of logs, sawing of timber,as well as, plaining and sanding of timbersurfaces to obtain a smooth finish. Wood <6> canbe divided in to two main types, Softwood(Coniferous) and Hardwood (Deciduous). Themain constituents of wood are, cellulose,hemicellulose, lignin, as well as, extractives:resin acids, fatty acids, turpenoid compounds,and alcohols. All these are carbohydrates(formed by the combination of the elements C,H and O), synthesized by the plant for variousfunctions.

Cellulose (6) is a polysaccharide (polymerformed by combination of sugar molecules). Itis formed within a plant by naturalcondensation polymerization of glucose(CttluOf,) and has the general formula(C6HioOs)n , where n is called the degree ofpolymerization (DP) and is around 600-1500for commercial wood. The polymeric linkagesduring cellulose synthesis are such that thechains form in an extended manner. As aconsequence, cellulose molecules fit snuggledtogether over long segments, giving rise topowerful associative forces that areresponsible for the greater strength ofcellulosic materials. The properties ofcellulosic material are related to DP ofcellulose molecules. Long chain cellulose isknown as alpha cellulose. A number ofshorter chain polysaccharides, knowncollectively as hemicellulose, also form parts ofthe woody structure of a plant.Hemicelluloses are polysaccharides formed bynatural condensation polymerization of five (5)different sugars, namely, hexoses: glucose,mannose, galactose and pentoses: xylose andarabinose. Hemicelluloses are categorizedaccording to DP as, beta cellulose (DP - 15 to90) and gamma cellulose (DP less than 15).

Lignin is a highly polymerized, amorphousmaterial available in wood. Its principal role isto form the middle lamella, the intercellularmaterial which cements the fibers together.The structure of lignin mainly consists ofphenyl propane units linked together in threedimensions.

6. Some Reasons for the Inability ofMicrobes to Breakdown (Digest) SawDust

It is well documented in literature that it isextremely difficult to breakdown SD byanaerobic or aerobic microbes. Informationobtained through interviews the authorconducted with owners and operators of sawmills clearly indicated that many of them hadtried to produce biogas by anaerobic digestionof SD while many others had tried to compostSD by burying in pits. In all these experiments,SD has not undergone any kind of digestionand had remained unchanged for years. Themain reasons that could be attributed to theinertness of SD towards micro organic activityare as follows.

1. Almost all the constituents of woodare chemically stable.

2. Some extractives are toxic to microorganisms.

3. To breakdown cellulose and lignin,which are the main constituents of SD,the enzymes cellulase and lignase (7>are required and most of the naturallyoccuring microorganisms do not havesuch capabilities.

4. Mainly nitrogen and to a lesser extentphosphorous are required bymicroorganisms for catabolism (?)(enzyme catalysed breakup of largemolecules of carbohydrate, fat andprotein into smaller molecules, whichproduces energy), anabolism^)(synthesizing large macro molecules,such as, polysaccharides, proteins andnucleic acids, which requires energy)and bioenergetics*7) (storing energyproduced by catabolism and releasingenergy for anabolism). The C:N ratioshould be 25:1 or more favourabletowards N. Such levels of N and P arenot available in SD.

7. Fundamentals of Composting

Composting*8'9'10-11'12'13) can be defined as aprocess by which aerobic microorganisms

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down organic matter and produce. . i 1 1 M in dioxide, water, heat, and humus.Under correct conditions of nutrition andMonition, composting proceeds through thefollowing three phases in chronological order.

l)'l'he Mesophilic Phase - a moderate-temperature phase, which lasts for a few days.2)'l'he Thermophilic Phase - a high-temperature phase, which can last for severalweeks.3)The Maturation Phase - at the end of thisphase the end product becomes stable.

The first phase of decomposition is carried outby mesophilic microorganisms, which rapidlybreak down the readily degradablecompounds. The heat produced causes thecompost temperature to rise rapidly. As thetemperature rises above 40°C, the mesophilicmicroorganisms become less active and arereplaced by thermophilic (heat loving)microorganisms commencing the secondphase of digestion. At temperatures of 50°Cand above, many microorganisms that arehuman or plant pathogens (harmful to humanand plants) are destroyed. Since temperaturesabove 65°C could kill both good and badmicrobes, thereby drastically reducing the rateof decomposition, it is important to managethe temperature below this point by cooling byaeration. During the thermophilic phase, hightemperatures accelerate the breakdown ofproteins, fats, and complex carboydrates likecellulose and hemicellulose, the majorstructural molecules in plants. As the supplyof these high-energy compounds becomesexhausted, the compost temperature graduallydecreases and mesophilic microorganismsonce again take over for the final phase of"curing" or maturation of the remainingorganic matter.

7.1 Some Microorganisms Who Play ASignificant Role In Composting*8*

7.1.1 Bacteria

Bacteria are the smallest and the mostdiversified group of living organisms whichconstitute 80% to 90% of the billions ofmicroorganisms typically found in a gram ofcompost. Bacteria are responsible for most ofthe decomposition and heat generation incompost. They are also the most nutritionallydiverse group of compost organisms, using abroad range of enzymes to chemically breakdown a variety of organic materials. Bacteria

are single-celled and structured as either rod-shaped bacilli, sphere-shaped cocci or spiral-shaped spirilla. Many are motile, meaning thatthey have the ability to move under their ownpower. At the beginning of the compostingprocess (0-40°C), mesophilic bacteriapredominate. Most of these are forms that canalso be found in topsoil. As the compost heatsup above 40°C, thermophilic bacteria takeover. The microbial populations during thisphase are dominated by members of the genusBacillus. The diversity of bacilli species is fairlyhigh at temperatures from 50-55°C butdecreases dramatically at 60°C or above. Whenconditions become unfavorable, bacilli surviveby forming endospores, thick-walled sporesthat are highly resistant to heat, cold, dryness,or lack of food. They are ubiquitous in natureand become active whenever environmentalconditions are favorable. At the highestcompost temperatures, bacteria of the genusThermus have been isolated. Composterssometimes wonder how microorganismsevolved in nature that can withstand the hightemperatures found in active compost.Thermus bacteria were first found in hotsprings in Yellowstone National Park and mayhave evolved there. Other places wherethermophilic conditions exist in nature includedeep sea thermal vents, manure droppings,and accumulations of decomposing vegetationthat have the right conditions to heat up just asthey would in a compost pile. Once thecompost cools down, mesophilic bacteria againpredominate. The numbers ?nd types ofmesophilic microbes that recolonize compostas it matures depend on what spores andorganisms are present in the compost as wellas in the immediate environment. In general,the longer the curing or maturation phase, themore diverse the microbial community itsupports.

7.1.2 Actinomycetes, Fungi, Protozoa and

Actinomycetes give the characteristic earthysmell to soil and resemble fungi, although theyare actually filamentous bacteria. They lacknuclei, but they grow multicellular filamentslike fungi. In composting they play animportant role in degrading complex organicssuch as cellulose, lignin, chitin, and proteins.Their enzymes enable them to chemicallybreak down tough debris such as woodysteins, bark, or newspaper. Some speciesappear during the thermophilic phase, andothers become important during the cooler

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curing phase, when only the most resistantcompounds remain in the last stages of theformation of humus. Actinomycetes form long,thread-like branched filaments that look likegray spider webs stretching through compost.These filaments are most commonly seentoward the end of the composting process, inthe outer 10 to 15 centimeters of the pile.Sometimes they appear as circular coloniesthat gradually expand in diameter.

Fungi include moulds and yeasts, and they arecollectively responsible for the decompositionof many complex plant polymers in soil andcompost. In compost, fungi are importantbecause they break down tough debris,enabling bacteria to continue thedecomposition process once most of thecellulose has been exhausted. They spread andgrow vigorously by producing many cells andfilaments, and they can attack organic residuesthat are too dry, acidic, or low in nitrogen forbacterial decomposition.

Most fungi are classified as saprophytesbecause they live on dead or dying materialand obtain energy by breaking down organicmatter in dead plants and animals. Fungalspecies are numerous during both mesophilicand thermophilic phases of composting. Mostfungi live in the outer layer of compost whentemperatures are high. Compost moulds arestrict aerobes that grow both as unseenfilaments and as gray or white fuzzy colonieson the compost surface.

Protozoa are one-celled microscopic animals.They are found in water droplets in compostbut play a relatively minor role indecomposition. Protozoa obtain their foodfrom organic matter in the same way asbacteria do but also act as secondaryconsumers ingesting bacteria and fungi.

Rotifers are microscopic multicellularorganisms also found in films of water in thecompost. They feed on organic matter and alsoingest bacteria and fungi.

8. A Brief Description of Delta-DTechnology (W-4)

By using Delta-D Technology, all types oforganic waste matter can be digested within afew hours, by mixing with a digestive fluidcalled Delta-D. After digestion, an acidicorganic slurry is obtained, which is mixed with

Eppawela Rock Phosphate, Dolomite, Mica,etc., to increase the N/P/K/Mg and othermicronutrient levels, while neutralizing Delta-D, in the organic fertilizer produced. Thisproduct is sieved and the powder is packedand sold as organic fertilizer. Undigested largeparticles of organic matter remaining on thesieve are recycled back to the process and thepolythene, plastics,, metal and glass particlesthat remain on the sieve are cleaned and soldto recycling companies.

The main advantage of Delta-D Technology, isthat, digestion can be done within a few hours,whereas, traditional processes, such as,composting and biogas generation requiremore than 3 months to digest organic waste,due to which, large quantities of Urban SolidWaste have to be stockpiled for severalmonths, requiring large extents of land.Another advantage of this process, is that, itproduces pathogen free, odorless, organicfertilizer richer in N,P,K,Mg and othernutrients than traditional compost. Theprocess does not produce leachate which is ahighly polluting liquid with high BOD andCOD values, commonly produced in opendumps, landfills and composting plants.Another unique feature of the process is thevalue addition to local, naturally occurringminerals, such as, Eppawela Rock Phosphate,Dolomite, Mica, etc. to produce a nutrient richorganic fertilizer.

The composition of the digestive fluid has tobe varied according to the composition of theorganic waste that has to be decomposed, aswell as, the rate at which the organic matter isto be digested. The composition of thedigestive fluid required to digest saw dust,straw or paddy husk will be different to thatrequired to digest fruit and vegetable wastewhich in turn will be different to that requiredto digest fish and meat waste. Hence thecomposition of the digestive fluid will bedecided on the basis of the waste to bedigested at any given time.

The composition of the digestive fluid has tobe varied according to the level of disinfectionrequired in the organic fertilizer, as well. Forexample, if the organic waste consists of highlyinfectious material, such as, rotten fish, meat,sewage, or clinical waste produced inhospitals, etc., the composition of the digestivefluid can be adjusted to automatically increasethe temperature of the digestive mix to 100°Cor more, so that all harmful pathogenic micro-

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organism are automatically destroyed. AfterI lit- digestion is complete, a thick, darkbrownish, acidic slurry, is produced which canlu' neutralized using a mineral powder mix.'I'lio composition of the mineral powder willili'pc-nd on the required composition of thefinal product, which will be an organicfertilizer containing water soluble N, P, K, Mg,Ca and other nutrients. The following rawmaterials are used to produce the digestivefluid Delta-D and the Mineral Powder Mixwhich is used to neutralize the slurry. One ofthe most important properties of Delta-D isthat it only catalyses digestion, which meansthat after the digestion process is over theDelta-D originally added will remain in thesystem and it is possible to use the Delta- D todigest more and more organic matter.

Raw Materials used to Produce the Digestive FluidEppawela Rock Phosphate (Apatite),Phosphoric Acid, Sulphuric Acid, Nitric Acid,Acetic Acid, Citric Acid, Sugar, Starch, Fruitand Vegetable Waste, Fish Waste, Saw Dust,Rice Straw or Paddy Husk.Raw Materials used to Produce the MineralPowder MixEppawela Rock Phosphate (Apatite), Dolomite,Calcite, Powdered Mica, Powdered Quartz,Mixed Salt from Sea Bitterns, Iron Ore,Foundry Slag, Zinc Ore, etc.

8.1 How Does Delta-D Digest OrganicMatter? (

Delta-D has a chemical combination that candigest all types of natural organic matter bycarrying out the following reactions. One of itsmajor features is to initiate catabolism(breaking down) of complex carbohydrates,proteins, etc., with acidic action andsubsequently mobilize enzymes available inorganic matter, as well as, enzymes secreted bymicroorganisms to continue the process.

1. Dehydration.2. Hydration.3. Oxidation.3. Breaking down of complex molecules, suchaj, cellulose, starch, proteins, oils and fats.4.. Converting organic, N, P, K, Ca, M, Na, Fe,Mn, Mo, etc. into inorganic, water soluble

forms.

8.2 Demonstrations of Delta-D TechnologyCarried Out In Sri Lanka

Delta-D Technology has been demonstrated atseveral government institutions, such as, TheInstitution of Engineers of Sri Lanka, Ministryof Agriculture (Govijana Mandiraya)University of Moratuwa, Horana UrbanCouncil, Maharagama Urban Council, LankaPhosphates Ltd., The Central EnvironmentalAuthority, and several leading privatecompanies, such as, The Lodge Habarana, TheConfifi Group of Hotels, Pussellawaplantations, Horana Plantations, CICFertilisers, Keells Food Products, Nelna Farm,Mandarin Farm and several other poultryfarms. Presentations and demonstrations havebeen, made at the Mahaweli Ministry, at aworkshop organized by Janatha FertiliserEnterprises, attended by Hon. ChamalRajapakse, Minister of AgriculturalDevelopment and 60 personnel comprisingMayors and Chairmen of MCs, UCs and PCsin the Southern Province. A demonstrationwas also carried out at The CentralEnvironmental Authority, Parisara Piyasa,Battaramulla, on behalf of the Horana UrbanCouncil to obtain CEA approval for a plant tobe constructed at Horana. The process hasbeen tested with all types of biomass and thefertilizer produced has been tested bycultivating, rice, vegetables and fruitssuccessfully. With the support of the JanathaFertiliser Enterprises, a corporation under theMinistry of Agricultural Development, around1330 entrepreneurs have been trained toconvert rice straw into organic fertilizer usingthis technology. The technology has beenintroduced to several local authorities torapidly convert USW into organic fertilizer.

8.3 Presentation Of Delta-D Technology AtNational and International Conferences

The author attended the 22nd InternationalConference on Solid Waste Technology andManagement, conducted by The WidenerUniversity, Philadelphia, USA, during theperiod 18-21 March 2007 and presented tworesearch papers on conversion of solid wasteinto organic fertilizer. The author alsoattended the 23rd International Conference onSolid Waste Technology and Management,conducted by The Widener University,Philadelphia, USA, during the period 30th

March to 2nd April 2008 and presented oneresearch paper on conversion of solid wasteinto organic fertilizer using Delta-D

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Technology. The author in collaboration withtwo other authors presented one researchpaper at the First International Conference onSolid and Rock Engineering held in 2007August in Colombo, Sri Lanka , conducted byThe Geotechnical Society of Sri Lanka. Theauthor also presented one research paper onDelta-D Technology at the Annual Sessions ofThe Institution of Engineers Sri Lanka, held inOctober 2007. Titles of these research papersare given in the list of references.

8.4 Recommended Methods For Using Delta-D Technology To Produce Organic Fertiliser

Research conducted by the author on wastematerial, such as, rice straw, farm waste andmarket waste has lead to the development ofthe following methods of using Delta-DTechnology to produce organic fertilizer..

(A) The Recommended Method For RapidDigestion Of Rice Straw In Dry ZonesMaking

Maximum Use Of Long Periods OfSunshine

1) 35 kg of dry rice straw is wetted with asolution of llitre of Delta-D mixed with 50litres of water.2) The wetted straw is laid on plastic sheetsand exposed to the sun for 3 days.3) After 3 days the straw crumbles intopowder.4) The 35 kg of digested straw is wetted with10 litres of water and is mixed with 5 kg of

Eppawela Rock Phosphate (ERP) and storedfor 2 days.5) The mixture produced in step 4 is mixedwith 500g of Dolomite (D).6) Now the product is ready for use as the firstfertiliser application for paddy cultivation.7) For other annual crops and perennial crops,the composition of the fertilizer can beadjusted by

adding plant and animal wastes digestedwith Delta-D to the digested straw.

(B) The Recommended Method For RapidDigestion Of Rice Straw In Wet Zones.

Even in the wet zones of Sri Lanka there isample sun shine right through the year. Hence,Method A can be practiced most of the time.However, if there are rains and it is notpossible to expose the straw to sunshine, thefollowing method should be followed.

1) 35 kg of dry rice straw is wetted with asolution of 2 litres of Delta-D mixed with 50litres of water.2) The wetted straw is stored in a dry area for 5days.3) After 5 days the straw crumbles intopowder.4) The 35 kg of digested straw is wetted with

10 litres of water and is mixed with 10 kg ofERP and stored for 2 days.

5) The mixture produced in step 4 is mixedwith 1 kg of D.6) Now the product is ready for use as the firstfertiliser application for paddy cultivation.7) For other annual crops and perennial crops,the composition of the fertilizer can beadjusted by

adding plant and animal wastes digestedwith Delta-D to the digested straw.

(C) The Recommended Method For RapidDigestion Of Poultry, Cattle and Pig FarmWaste

1) Excreta of animals, including urine iscollected and mechanically mixed into aslurry.2) Per 100 liters of the slurry, 30 kg of,sawdust, straw or any other type of drycellulose material

is added and well mixed.3) 2 liters of Delta-D is added to the above mixand allowed to react for 5 days.4) After 5 days, 10 kg of ERP is mixed to it andallowed to react for 2 days.5) The mixture produced in step 4 is mixedwith 1 kg of Dolomite.6) Now the product is ready for use.

(D) The Recommended Method For RapidDigestion Of Fruit And Vegetable Waste(FVW)

1) FVW is chopped to a size below 25mm (L) x25mm (W) x 5mm (T).2) Per 50 kg of FVW, 1 liter of Delta-D isadded, well mixed and allowed to react for 2days...3) After 2 days 20 kg of dry saw dust is mixedwith the slurry and allowed to react for 2 days4) After 2 days 5 kg of ERP is mixed to it andallowed to react for 2 days.4) The mixture produced in step 4 is mixedwith 1 kg of Dolomite.5) Now the product is ready for use.

Table-1 and Table-2 give the chemical analysisof organic fertilizer produced from straw and

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combinations of straw, cow dung, poultrydung and fruit and vegetable waste using theabove procedure.

9. The Research Project on Delta-DInitiated Microorganic Digestionof Saw Dust into OrganicFertiliser

The main objective of the research project wasto study the rates of biodegradation ofdifferent species of SD,. under differentmoisture contents and under the influence offish and vegetable market waste digested byDelta-D.

9.1 Equipment, Instruments, Materials andMethods:

9.1.1 Equipment and Instruments

SD had to be digested in containers, to controlthe moisture content and to measure thetemperature. It was decided to use 200 literplastic barrels, cut into half to obtain halfbarrels of capacity around 100 liters each.These were thoroughly washed withdetergents and water to ensure the absence ofmaterials toxic to microorganisms. Thecylindrical walls of barrels were perforated,from top to bottom, at 6" intervals verticallyand horizontally, with a 8mm drilling tool, inorder to provide air to microorganisms. A 250kg Avery Platform Weighing Scale was usedfor weighing of material. A MercuryThermometer of range 0°C - 100°C was used tomeasure temperatures.

9.1.1.1Material

SD produced out of wood species, Jack (J),Mahogany (M), Teak (T) and Rubber (R), wereseparately collected into bags from the LintonSaw Mill, located 1 km away from the researchstation. In order to ensure that chemicals werenot present, SD due to sawing of logs werecollected.

9.2 Digestion of Fish and Vegetable Wasteusing Delta-D

Fish market waste and vegetable marketwastes were collected from the PanaduraMarket. Fish waste consisted of heads, skins,fins, bones, bowels, etc. Vegetable wastemainly consisted of rotten cabbage, leeks,radish, salad leaves, carrots etc. 100 kg of fishwaste was digested with 2 liters of Delta-D, to

obtain fish waste slurry (FWS). 100 kg ofvegetable waste was digested with 2 liters ofDelta-D, to obtain a vegetable waste slurry(VWS). FWS and VWS were thoroughly mixedtogether to obtain around 206 kg of mixedslurry (MS). The dry solid content of MS wasmeasured by drying a sample of 20 g of wellmixed MS using a UV Lamp Moisture Balanceand was found to be around 32 %. Hence, 5 kgof MS contained 1.6 kg solids and 3.4 kg ofwater. For convenience it was assumed thatthere were no components with boiling pointsbelow 105°C, other than water.

9.3 Preparation of Saw Dust (SD) Samplesfor the Research Project

From SD of each of the wood species, six (6) 25kg samples were taken and filled into six (6)100 liter barrels. Water and MS were added toSD and thoroughly mixed as given in Table 3.In Table 3, Ty, T2j, T3j, T4j, T5j, T6j ; TIM, TIM/TSM, T4M, TSM, T6M, etc., refer to samplesprepared by mixing variable quantities ofwater and MS to SD species, Jack, Mahogany,etc. All the barrels were covered with cleartransparent polythene of 200 gauge thickness,perforated at 6" intervals, to prevent excessivemoisture loss without compromising microbialrespiration. The thirty (30) samples were keptin a cool place in a building with an asbestoseroof covered on three (3) sides, in order toprevent excessive moisture loss due sunlightand wind.

9.4 Moisture Control, TemperatureMeasurement and Data Analysis

Since a sufficient moisture content (M) isrequired for bacterial activity in composting,M had to be maintained at a constant level.The method adopted was to take the weight ofeach barrel after adding water and MS (as perTable 3) and to mark it on each barrel as theweight on the first day of the experiment. Onci1

in.5 days, each barrel was weighed and mi-weight difference (WD) was calculated bydeducting the current weight from the weigh!on the first day. WD was considered to be themoisture loss (ML) due to evaporation and anequal amount of water was added and mixt'ilwith SD in each barrel to compensate for M l .On days when ML was compensali'il,temperature readings were not taken.

As described in Section 7.0 - Fundamenliil.s olComposting, whenever there is aerobic microorganic activity, the temperature (T) in tin1

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compost pile rises above ambient temperature.Hence, temperature (T) at the centre of eachSD barrel was measured at 12.00 hrs each dayfor a period of time until the temperaturereached ambient temperature. Table 5 andTable 6 give the readings of temperature withtime for all the samples. From Tables 4 and 5, itis quite evident that there was no appreciabletemperature rise in samples of SD which didnot contain MS, indicating negligible aerobicmicrobial activity in the samples. However, insamples of SD which contained MS, thetemperatures rose significantly, indicatingstrong aerobic microbial activity. For allspecies of SD the highest temperaturesrecorded were for samples which had MS and50% moisture. The temperatures recorded forsamples which had MS, but lower moisture(40% and 45%) contents, the temperatureswere lower than for 50% moisture. The highesttemperature of 56°C was recorded in RubberSD with MS and 50% moisture, whichindicated highest aerobic micro organicactivity, compared to other samples. For allsamples of SD with MS, the temperaturesreached maximum values within 30 days andtemperatures started dropping within 40 days,clearly indicating that the composting processis initiated and accelerated by MS.

9.5 Manufacture of Organic Fertiliser fromMS Digested Saw Dust

The final step in the manufacture of OF fromSD digested with MS was to mix EppawelaRock Phosphate (ERP) and Dolomite (D) asgiven in Table 2, which is, Delta-D : ERP :Dolomite = 1L : 5kg : 1kg. Since, 5kg of MSwhich contains 200ml Delta-D was add to eachbarrel, the quantities of ERP and Dolomite tobe added to each barrel were 1kg and 200grespective. After addition of ERP and D the SDwas thoroughly mixed and allowed to react for3 days. The product

10. Agricultural Trials Conducted toCheck the Suitability of the OrganicFertiliser

The suitability of the MS Digested OrganicFertilizer (MSOF) produced was tested byapplying to mature plants and tender plantsof, fruit varieties; Papaya, Guava, Mango andAmbarella and vegetable varieties, ladiesfingers, egg plant, capsicum, slender gourd,bitter gourd and long beans.

10.1 Results

When MSOF was applied to mature andtender plants of fruit varieties: Papaya, Guava,Mango and Ambarella and vegetable varieties:ladies fingers, egg plant, capsicum, slendergourd, bitter gourd and long beans in bothfruits and vegetables, there was significantenhancement of growth rate, which wasevident from, new offshoots of branchesspringing up within 1 week and continuing togrow unhindered. The colour of leaves weredark green showing that there was no nitrogenor magnesium deficiency. At present, a studycomparing the performance of MSOF withtraditional N,P,K,Mg fertiliser is underway ofwhich results will be available in December2009. The data will be published during thefirst quarter of 2009.

11. Economical Feasibility ofComposting Saw Dust by theCombined Process of Delta-DTechnology and Aerobic MicroOrganic Activity

Results of the research project clearly indicatethat it is technically possible to produce OFfrom SD using the above process. In order tosee whether the process is economically viable,it is necessary to estimate the capital costrequired and the operational costs.

11.1 Capital Cost

The process consists of the following threemain operations, which can be carried outmanually or mechanically.

(a) Digestion of, fish (animal) waste and fruitand vegetable waste using Delta-D toproduce Mixed Slurry (MS) -This operation requires, several 200 L

Plastic Barrels. Each barrel costs aroundRs.1200 and can produce 200 kg of MS per2days.

(b) Mixing water and MS with SD - This can becarried out manually using shovels.(c) Final mixing of ERP and Dolomite - Thisoperation can be carried out manually usingshovels.(d) Weighing and storage of raw materials, aswell as, weighing, packing, storage and sale offinished product.

If the production per day is below 5 TPD,manual operations can be carried out and the

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capital costs will be minimal. However iflarger production capacities are required,operations can be carried out using electricmotor or engine driven mechanical mixers,which will require capital in proportion to theplant capacity. Since, Capital Cost varies withthe degree of mechanization, costs of land,buildings and other infrastructuralrequirements, this aspect is not discussedunder this section.

11.2 Operational Costs - and EconomicFeasibility

The operational costs, profits and thefeasibility of manufacturing OF is summarizedin Table 4. Operational costs consist of DirectCosts (direct raw material, packing materialand labour requirements) and Overheads. Inthe following analysis, all costs other thanDirect Costs have bee lumped into Overheads.

12. Conclusions

1. Saw dust (SD) cannot be compostedwith only moisture, since naturallyoccurring microorganisms areincapable of secreting enzymes thatcould break down components in SD.

2. Delta-D initiated micro organicdigestion of SD into organic fertilizer(OF) is a technically, economically andenvironmentally feasible solution tothe SD problem in Sri Lanka, since,composting can be done fast and theOF can be sold at a low price evenwith a profit margin, benefiting theproducer of OF and the farmers. TheGOSL can reduce the annual cost ofurea fertilizer subsidy and theenvironment hitherto polluted due tohaphazard dumping or burning ofsaw dust can be conserved. .

3. Since, saw dust and similar highcellulose material, such as, straw,paddy husk, leaves of plants, grass,weeds, etc., are available all over thecountry, production of organicfertilizer can be decentralized, so that

OF is produced in agricultural areas,which reduces, capital cost, workingcapital, operational costs andtransport, there by further reducingfertilizer costs.

4. Since most imported chemical. fertilizers prices (CFP) are sensitive to

crude oil prices (COP). With risingCOP, CFP too will increase in thefuture. However, since the rawmaterials required for OF are locallyavailable, OF prices will remain stable.

5. More self employment type jobs willbe created if OF industry is mooted bythe GOSL and the private sector.

Acknowledgements

I take pleasure in thanking all those whohelped me to carryout this research project,namely, Ranjani Perera - Manager, CharithPerera - Partner, Maheshika Perera - Partner,M. Alahudeen - Foreman, A. Hassan - PlantOperator, S. Sampath - Plant Operator,Dayawathie Fernando and Deulet Fernando(employees) of Sea way Enterprises ofPanadura.

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Table 1 - Chemical Analysis of Organic Fertiliser Produced from Straw, Cow Dung andPoultry Dung Using Delta-D Technology As First Application For Paddy Cultivation

ComponentMoisture %OrganicCarbonTotal N%Total P2O5%Total K2O%

Straw Only30.028.5

0.606.801.40

90 %Straw+10 % Cowdung30.028.7

1.277.101.60

90%Straw+10%Poultrydung30.028.9

1.837.801.87

Table 2 - Chemical Analysis of Organic Fertiliser Produced from PL and FVW

Species

Moisture %OrganicCarbon %Total N%Total P2O5%Total K20%

Formula For Tender Rubber PlantsPoultry Litter 1000 kgDelta-D 40 LERP 160 kgDolomite 75 kg30.2433.42

1.866.800.93

Formula ForFVWDelta-DERPDolomite

Vegetables1000 kg

20 L100kg20kg

38.3129.70

0.674.300.62

Table 3- Wood Species and Type of Treatment

WoodSpecies

Jack

Mahogany

Teak

Rubber

SD:H2O:MSRatio=25:16:0H2O =40%Water 16kgadded to 25kgof Dry SD.Sample No:TijWater 16kgadded to 25kgof Dry SD.Sample No:TIM

Water 16kgadded to 25kgof Dry SD.Sample No:TrrWater 16kgadded to 25kgof Dry SD.Sample No:TIR

SD:H2O:MSRatio=25:20:0H2O =45%Water 20kgadded to 25 kgof Dry SDSample No: T2j

Water 20kgadded to 25 kgof Dry SDSample No:T2M

Water 20kgadded to 25 kgof Dry SDSample No: T2i

Water 20kgadded to 25 kgof Dry SDSample No: T2R

SD:H2O:MSRatio=25:25:0H2O =50.00%Water 25kgadded to 25kgof Dry SDSample No: TSJ

Water 25kgadded to 25kgof Dry SDSample No:T3M

Water 25kgadded to 25kgof Dry SDSample No: TST

Water 25kgadded to 25kgof Dry SDSample No: TSR

SD:H2O:MSRatio=25:12.6:5H2O =40%Water 12.6kgMS 5 kgadded to 25 kgof Dry SDSample No: T<IJWater 12.6kgMS 5 kgadded to 25 kgof Dry SDSample No:T4M

Water 12.6kgMS 5 kgadded to 25 kgof Dry SDSample No: JnWater ! 2.6kgMS 5 kgadded to 25 kgof Dry SDSample No: 1\n

SD:H2O:MSRatio=25: 16.6:5H2O =45%Water 16.6kgMS 5 kgadded lo 25 kgof Dry SDSample No: TSJWater 16.6kgMS 5 kgadded ID 25 kgof Dry SDSample No:Tr,MWater 16,6kgMS 5 kK

ded to 25 kg ofDrySDSample No: TJIWater 16.6kgMS 5 kgadded ID ."• kgof Dry SI)Sample No: TJR

SD:H2O:MSRatio=25:21.6:5M2O =50.00%Water 21 .6kgMS 5 kgadded lo 25 kgof Dry SDSample No: T&jWater 2 1.6kgMS 5 kgadded lo 25 kgof Dry SDSample No:TiMWater 2 1.6kgMS 5 kg, ul tied lo 25 kgof Dry SDSample No: TeiWater 2 1.6kgMS 5 kgadded to 25 kgof Dry SDSample No: TeR

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Table 4- Feasibility of Composting SD by Combined Process of Delta-D Technology & AerobicMicroorganism

Raw Materials andLabour Required ToManufacture MixedSlurry (MS)

Fish WasteVegetable WasteDelta-DLabour (it is assumedthat 1 labour unit issufficiwnt to produce200 (MS)

Raw Materials andLabour Required ToManufacture 50 kgOrganic Fertiliser (OF)from Saw DustWaterMixed SlurryDry Saw DustERFDolomite (D)Labour (it is assumedthat 1 labour unit issufficient to produce250kg)Packing Material 25 kgPP

Quantities

100kg100kg

4 LlUnit

Quantities

21.6 L5.0kg

25.0 Kg2.0kg0.4kg

1/5 Unit

2 Bags

Unit Cost(includescollection,handling andtransport)Rs. 5.00 per kgRs. 5.00 per kgRs. 200.00 per LRs. 700.00 perUnit

Unit Cost(includescollection,handling andtransport)Rs. 0.20 per LRs. 12.50 per kgRs. 5.00 per kgRs. 10.00 per kgRs. 5.00 per kgRs. 700.00 perUnit

Rs. 15.00 per bag

Costs / Profits

Rs. 500.00Rs. 500.00Rs. 800.00Rs. 700.00

-Total Cost to Produce 206 kg MS Rs.2500.00Total Cost to Produce 1 kg MS Rs. 12.50

Cost

Rs. 4.30Rs. 62.50Rs. 125.00Rs. 20.00Rs. 2.00Rs. 140.00

Rs. 30.00

-Total Direct Costs to Produce 50 kg Rs. 383.00Total Direct Costs to Produce 1 kg Rs. 7.66Cost of Overheads 31 % per kg Rs 2.34Total Cost to Produce 1 kg Rs. 10.00Proposed Selling Price Rs. 15.00Profit per kg Rs. 5.00

If production capacity is 1 TPD, profit per day willbe Rs. 5000 and the profit per year (300 days) willRs. 1,500,000.

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Table 5 - Time (Days) Vs Temperature (°C) Readings For Jack SD and Mahogany SD

TimeDays

I23457891011131415161719202122232526272829313233343537383940414344454647495051525354555657

TijT°C

28282828282929292929292929293131313131313131313131323232323232313131313131313131313131313131313131

T2JT°C

28282828282929292929292929293131313131313131313131323232323232313131313131313131313131313131313131

TsjT°C

28282828282929292929292929293131313131313131313131323232323232313131313131313131313131313131313131

T4J

T°C

28334042424343444444474747474747474848484848484848484848484848484848484747454444433936343231313131

TsjT°C

28354246464646474747484849494951525252525252525252525252525050504949484846464444423935333232313131

TejT°C

28354550505050505050515151515151525252525353535353535353535350504949494844413837363534333131313131

TIMT°C

28282828292929292929292929293131313131313131313131323232323232313131313131313131313131313131313131

T2M

T°C

28282828282929292929292929293131313131313131313131323232323232313131313131313131313131313131313131

TSMT°C

28282828282929292929292929293131313131313131313131323232323232313131313131313131313131313131313131

TIMT°C

28303335384042434345454545454545454545454545454546464646464646464646464646464644424038363331313131

TSMT°C

28333842434343444444464848484949494950505050505050505050505050504848464543434040393733333231313131

TBMT°C

28354550505050505050515151515151525252525353535353535353535350504949494844413837363534333131313131

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Table 6 -Time (Days) Vs Temperature (°C) Readings For Teak SD and Rubber SD

TimeDaysI23457891011131415161719202122232526272829313233343537383940414344454647484951525354555657

TITT°C

28282828282929292929292929293131313131313131313131323232323232313131313131313131313131313131313131

T2TT°C

28282829292929292929293030303131313131313232323232323232323232323232323232323232323232323232323232

T3TT°C

28282828283030303030303131323232323232323232323232323233333333333333333333333333333333333333333333

T4TT°C

28334042424343444444474747474747474848484848484848484848484848484848484747454444433936343231313131

T5TT°C

28354246464646474747484849494951525252525252525252525252525050504949484846464444423935333232313131

T6TT°C

28374853535353535353535454545555555555565656565656545453525250494947454443413936353533323131313131

TlR

T°C

28282828292929292930303030303232323232323333333333333333333332323232323232323232323232323232323232

T2RT°C

28282828282930303131313232323232323333333333333333333333333333333333333333333333333333333333333333

T3RT°C

28293030313132323233333333333434343434343434343434343434343434343535353535353535353535353535353535

T4R

T°C28364243444546474951515151525252525253535353535353535353535353535252525048464442424038363232313131

T5RT°C

28364144464951515151525252535353535353535354545454545454545454545454545250494644403735333231313131

TBRT°C

28374853535353535353535454545555555555565656565656545453525250494947454443413936353533323131313131

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Time Vs

Time Vs I Witti MS

1 13 15 17 19 21 23 25 27 29 31 33 35 31 3 5

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International Conference on Solid WasteTechnology and Management March 2007,pp. 1301-1311 © Widener University,Philadelphia, USA.

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