Daur ulang plastik (plastic recycling)

Plastic recycling requires cooperation management to ensure utilization and pricing of recycled plastic between father company and production center. This idea purposes to stimulate entrepreneur to ensure their capital pay back time and sustainability of this activities. Recycled plastic is prepared through crushing and grinding step after stratifying of raw materials.

Fig. Plastic crushing

(Courtesy of TokoMesin, 2012)

The plastic material code indicates material type of plastic product. It is visible as number code in triangle on the bottom side of product such as bottle, container, etc.

Number 1 : PET, polyethylene terephthalate

Number 2 : HDPE, high density polyethylene

Number 3 : PVC, polyvinyl chloride

Number 4 : LDPE, low density polyethylene

Number 5 : PP, poly propylene

Number 6 : PS, poly styrene

Number 7 : Others

Biodegradable municipal waste consists of organic waste 73%, paper 9%, plastic 9%, and others. For instance, the Paris van Java area is occupied by 2.5 millions people. This area releases municipal waste 1250 tons waste per day. It means we can save plastic 112.5 tons per day. In 2009 lack of polypropylene reached 250 thousands tons of total consumption around 800 thousand tons.

The plastic recycling requires storage and production area 400 – 1000 square meters. Machinery provider and pioneer company offer their assistance to somebody who interests to recycle plastic product. They provide machinery and training assistance for technician to operate the machine.

Sampah organik perkotaan (biodegradable municipal waste)

Nowadays we should progressively divert biodegradable municipal waste from landfill. European community proposed this strategy years ago. They encourages reducing their dependence on land-filling municipal waste and changes to more environmentally sound alternatives. 

The integrated waste management strategy establishes the preferred options for dealing with biodegradable municipal waste are:

(a). prevention and minimization, it means avoiding generating the waste

(b). recycling, including plastic and paper

(c). biological treatment, mainly of kitchen waste including composting

(d). residual treatment, thermal treatment or by mechanical-biological treatment.

Fig. Biodegradable municipal waste

(Courtesy of EBTKE, 2012)

Basically land filling is the worst waste management option for biodegradable waste. In specific cases the environmental balance among the options for the waste management depends on factors including collection systems, waste composition, climatic conditions, and potential reuse and recycling products. The waste management strategies should determine transparent manner based on a structured and comprehensive approach.

People releases biodegradable municipal waste in average of 0.5 kg/ capita /day. It means ten millions of Jakarta people releases 5,000 tons / day. The local government examined composting technology to convert municipal waste in the form of pellet or granular compost by employing exogenous microbes. The characteristic of compost fertilizer typically contains C organic 13%, N-total 3,53%, P-total 0,53%, K-total 4,44%, Ca 5,80%, Mg 1,34%, C/N ratio 10 after 14 days composting period.

Kayu bakar (firewood)

There are 400 tree species and 60 commercial timber species for export and domestic commodities. Wood has variety of specific density between 0.4 and 0.6. So far commercial timber is dominated by meranti wood (Shorea leptocladus sym.). Statistically, forest timber production as export commodity reached 41 millions tons and domestic up to 19 millions tons (2001).  In comparison, production of rice straw in similar year approached 71 millions tons and increased up to 97 tons within next decade. Cultivated forest areas are distributed over 12.8 millions hectares. Big part of them located in Kalimantan island covers 10.76 millions hectares.

In the other side, rural people need pieces of wood and small branch of wood as firewood. Since long time ago, it may be one of traditional energy sources for cooking. Nowadays around 14% of world energy supplies are fulfilled by biomass fuel. The rural and poor people use this biomass fuel for cooking.

Fig. Firewood

(Courtesy of Wordpress, 2012)

The disadvantages of this biomass fuel are smoke tendency and require more space of kitchen. Suburban people who live in limited space area are difficult to utilize firewood for cooking. Kerosene stove serves many people for last decades. However availability of this fuel has been phased out by government and substituted by liquefied petroleum gas. This gas is available in container of 3 kg or 12 kg for household application. This gas burns clearly than kerosene.

Sekam padi (rice husk)

Recently, national issue on energy crisis influences directly to rural and poor people. Gas energy supply is controlled by government through authorized agents or distributors and people pay for them. Lack of firewood enforces to create alternate energy to meet a demand.  Rice husk waste has potential application to be converted in form of shavings or briquette. However it needs a binder to adhere among them. Additional other solid waste also benefits to improve physical quality. Briquetting process can be performed with or without oven. The unhulled paddy contains 45% rice husk. Potential quantity of rice husk reaches 22,884,814 tons (2011) as side product or solid waste of paddy cultivation over 13,224,379 hectares.

Fig. Rice husk

(Courtesy of Antara, 2012)

The characterization of briquette quality depends on burning temperature, burning period, calorific value, physical property of product. The typical binder plays significant role in this product. Utilization of natural binder in the form of waste solves environmental problem at once. These solid waste area adhered with around 10% of natural binder may produce optimum physical properties of product and its calorific value. Research result obtained fact that different binders influence the calorific value of the briquette.

Proportion of raw materials may be varied to obtain best properties of product. Variety of natural binder may be applied in a single or combined proportion. The binder material can be selected from the waste residue of natural starch locally. It depends on availability of waste materials and possible binders. The characteristic of this fuel may flare within half hour at medium service temperature.

Possible conversion of rice husk and stem becomes bio fuel was regulated by government (2008). The reason is national food security consideration. It is worried if induces the price of rice commodity domestically. Within next decade government secures rice commodity from bio fuel demand issue.

Selulosa serat (fibrous cellulose)

Plants contain cellulose, hemicelluloses and lignin. The cellulose appears as micro fibrils with diameter size between 2 to 20 nm and length size of 100 to 40,000 nm. Cellulose has most important use to hold on to water. Water molecule cannot penetrate crystalline cellulose. Dry amorphous cellulose absorbs water to become soft and flexible. If the cellulose has high crystallinity, less water is bound by direct hydrogen bonding. However some fibrous cellulose can hold on to considerable water in pores and its typically straw-like cavities. Water holding ability correlates with the amorphous surface area effect and porosity.

Fig. Cellulose structural unit

Plant fibers are group into seed fiber (cotton, kapok), leaf fiber (sisal, banana, agave), bast (stem skin) fiber (flax, jute, kenaf, hemp, ramie, rattan), fruit fiber (coconut/coir), and stalk fiber (straws of wheat, rice, barley, bamboo and grass). Cellulose content in each plant does not similar. For examples in dry basis, hardwood contains 42% cellulose, sugarcane baggage contains 41% and rice straw contains 45%. The characterization and its potential application of fibrous cellulose have being studied in the world.

Fig. Study on fibrous cellulose during last century

(Courtesy of Forest Product Laboratory, 1994)

Hemicelluloses refer to polysaccharide filling between fibrous cellulose in the plant walls. Hemicelluloses are polysaccharide that can be extracted by base solution. Hemicelluloses are mainly arranged by D-glucose chain monomers and other monosaccharide. The main component of hemicelluloses at dicotyledoneae is dominated by xiloglukan, whereas its composition may vary in monocotyledoneae. In wheat plant, it is dominated by arabinoxylane, whereas at barley and haver is dominated by betaglukan.

Lignin plays role as a binder of other components in plant tissue. If cellulose consists of carbohydrate groups, then chemical structure of lignin is very complex and has random pattern. Aromatic group is found in lignin, and cross linked by aliphatic chain consists of 2 to 3 carbons. In physical chemical process, lignin and hemicelluloses are usually separated from its cellulose to find better mechanical properties of new product involving as much as cellulose content.

Pupuk kompos (compost fertilizer)

Composting process degrades organic waste by means of microbes in humid and medium temperature either aerobic or anaerobically. The important steps include to prepare raw materials, sufficiently water addition, aeration adjustment and composting activator involvement. Composting activator examples ActiComp, BioPos, EM4, Green Phoskko Organic Decomposer, OrgaDec, Promoting Microbes, SuperDec, Superfarm or employing earthworm. 

Fig. Compost fertilizer

(Courtesy of Hendraagronom, 2012)

Compost raw material contains carbon and nitrogen in the from of manure, solid waste, wastewater, municiple waste or garbage. In composting process the ratio between carbon to nitrogen is approached by additional manure with high content of nitrogen. The optimum content of nitrogen compound preferably 2.5 to 5% compared to carbon compound.


Composting steps consist of activation step and maturity step within temperature between 30 to 70^oC. During process the mixture is turn up and down weekly. Practically it requires two weeks until two months period for compost to mature depends on treatment during process. The maturity of compost product indicated by black-brownist colour.

Neraca massa pangan (food mass balance)

Food mass balance in this term is defined as how many un husk rice are produced all over country and how much natural resources are required especially natural gas as raw material of synthetic fertilizer to ensure quantity target of rice cultivation.

Table of food mass balance :

Quantity of natural gas exploration: 2.95 tscf

- natural gas for export : 1.60 tscf

- natural gas for other : 1.02 tscf

- natural gas for fertilizer processing : 0.33 tscf

Natural gas for fertilizer processing : 6,379,560 tons 

Water for fertilizer processing : 22,966,416 tons

Air for fertilizer processing: 23,787,893 tons

Fertilizer for domestic consumption : 9,000,000 tons

Fertilizer for exported : n/a

Cultivated unhusked rice : 65,385,183 tons

Other cultivated products : n/a

Hulled rice : 42,500,369 tons 

Rice straw : 96,770,071 tons

Rice husk : 22,884,814 tons

Total rice field area : 13,224,379 hectares

Indonesia population 2011 : 240,778,999

The consumption rate of (hulled) rice for Indonesian people nowadays reaches 177 kgs per capita annually. Several alternative foods are being progressively developed. Development of new rice field purposes to increase required food mass in line with increased population.

Fig. Hulled rice  

(Courtesy of Kiranaagro, 2012)

Until now rice tungro virus disease is a threat to national rice production. The disease is caused by rice tungro spherical virus (RTSV) and rice tungro bacilliform virus (RTSV), and is vectored mainly by green leafhopper Nephotettix virescens. Tolerant rice varieties to RTBV that have been released, such as variety Tukad Unda, is able to survive at low to moderate disease pressure, but not at high one.  Of particular interest is a variety that resistant to RTSV, such as Tukad Petanu (parental variety: Utri Merah), is relatively more durable, where this variety has survived for more than 10 years.

The intensification research to improve new type of rice was being progressively developed. A number of promising rice variety were produced for example BP364B-MR- 33-3-PN-5-1. This type was released as the first variety of Fatmawati. This variety derived from a cross between upland rice line BP68C-MR-4-3-2 and an improved lowland rice variety Maros. Variety Fatmawati has the characteristics of sturdy stem, low to medium number of all productive tillers, long and dense panicle, early maturing, moderately resistant to brown plant hopper and bacterial blight, and have good grain and eating quality. In a multilocation trial, Fatmawati produced grain yield comparable to that of IR64. In 2011, an integrated crop management yielded 30% more than IR64.

Jerami padi (rice straw)

Organic decomposition anaerobically in the rice field release methane gas. Methane is wellknown as one of green house gas. Typical emission of methane gas in rice field varies between 100 until 800 kg per hectare per season. Optimization in rice cultivation technique alleviates methane gas emission either padi seed selection, organic fertilizer utilization, irrigation water adjustment, or herbicide application.

Fig. Rice straw on rice field

(Courtesy of Dept of Agriculture, 2007)

Padi (Oryza sativa, unhusked rice) cultivation also produces rice straw and rice husk. Traditional utilization of rice straw includes breed bedding, mushroom, pulp material, fuel and burn. Agriculture technology also explores of rice straw compost and animal feed with (ruminansia) or without fermentation  to improve added value of rice straw. Rice straw is also potentially utilized for animal feed through ammonization process by preparing 4% urea solution to immerse rice straw anaerobically within 1 to 2 weeks.

Each hectare of wet rice field release 5 tonnages of rice straw and 1 ton of rice husk. This biomass can be converted to electricity. It means that 1 MW electric requires 1500 hectares rice field. In a few quantity, rice straw was employed in nanoparticle research to calcinated temperature up to 1000^oC.

Paper industry employs rice straw as raw material for specific paper. Typical capacity of paper industry up to 5000 tonnages per annum at Padalarang - West Java utilizes rice straw raw material collected from farmers around paper plant area.

Abu sekam padi (rice husk ash)

Peeling process of rice grains releases rice hush as solid waste. Rice husk contains 15% weight of ash after burning process. The rice hush ash contains high silica content up to 96.25% through pyrolysis process is available in local market. Rice husk ash is well known as abu sekam padi.

Fig. Rice husk ash

(Courtesy of Anzettama, 2012)

Rice husk ash has many possible applications such as raw material of silicon carbide whiskers for cutting tool reinforcement. Traditional application of rice hush ash includes as concrete, ceramic and brick filler. Other application of silica fume replacement, chemical absorbent, insulation powder, or dry release agent in ceramic industry are also reported. Rice hush ash is also potentially processed to become raw material of natrium silicate through spouted bed reactor.

Rice husk ash was also studied to be employed in soil stabilization of expansive soil. Other researcher also reported rice husk ash role in combination with carbonate rock to stabilize fibrous peat for road foundation. Lime rock at amount 30% weight in its mixture with rice husk ash optimally further applied with peat at proportion of 10 : 90 in percentage by weight.

Arang hayati (biochar)

The biowaste processing of manure and cellulose wastes convert them to become biochar through burning process called pyrolysis. This biochar is probably known as arang hayati. Nowadays biochar is preferably utilized for land medium of orchid flower.

Fig. Biochar

(Courtesy of PTPN X, 2012)

Ancient Japanese called biochar as fire manure, whereas ancient Amazonese called biochar as terra preta. Rice grain contains of 18 to 22% rice hush, and proportionally with 45 to 55 % weight of rice straw.

Traditionally, farmers sometimes burn the rice straw and timber pieces to become biochar. This biomass residue is available in large amount all over country, however its utilization was never recorded properly.

Fig. Biochar production

(Courtesy of International Biochar Initiative, 2012)

Biochar role improves land nutrient for long period. It requires comprehensively examination of benefit either for land improver or fuel. Organic fertilizer benefits in shorter period than land improver. Pyrolysis produces biochar and bio-oil or typical biodiesel. However commercial activity in relation with convertion of rice straw into biodiesel was regulated due to social impact consideration.