Pengelolaan Limbah Bahan Kimia dan Reagen Laboratorium

Berdasarkan PP 101/2014, laboratorium, baik yang berupa laboratorium riset, komersil, klinis, maupun yang terdapat pada industri, merupakan salah satu sumber limbah B3. Salah satu jenis limbah B3 laboratorium yang umum dijumpai ialah bahan kimia dan reagen. Permasalahan utama untuk limbah laboratorium jenis ini ialah ukurannya yang kecil, konsentrasinya yang pekat, karakteristiknya yang bervariasi, dan jumlahnya yang besar akibat terakumulasi dalam kurun waktu tertentu. Semua ini menyebabkan masih banyak laboratorium yang belum mengelola limbah jenis ini. Karena termasuk dalam daftar limbah B3, maka limbah ini wajib dikelola dengan baik dan benar sesuai regulasi; tidak mengelola limbah B3 yang dihasilkan dapat dikenakan sanksi pidana sebagaimana diatur dalam UU 32/2009.

Pengelolaan limbah bahan kimia dan reagen laboratorium mengikuti prinsip cradle to grave chemical management, di mana pengelolaan dimulai dari pembelian, penerimaan, penyimpanan, penggunaan, hingga pembuangan. Kegiatan ini terdiri dari minimisasi, identifikasi, karakterisasi, segregasi, pengemasan, penyimpanan, pengangkutan, serta pembuangan yang terdiri dari pengolahan, pemanfaatan, dan penimbunan. Minimisasi, identifikasi, karakterisasi, segregasi, pengemasan, dan penyimpanan harus dilakukan sendiri oleh pihak laboratorium selaku penghasil limbah. Sedangkan pengangkutan serta pengolahan, pemanfaatan, dan/atau penimbunan dapat dilakukan sendiri jika memang memiliki izin, atau menyerahkannya ke pihak ketiga berizin jika tidak mampu melakukannya sendiri.

Kebanyakan limbah bahan kimia dan reagen laboratorium masih berada dalam kemasan aslinya. Dalam kasus seperti ini, lab pack procedure dapat diterapkan untuk memudahkan pengemasan tanpa perlu mengeluarkan isinya terlebih dahulu. Prosedur ini dilakukan dengan memilah dan mengelompokkan limbah bahan kimia dan reagen berdasarkan karakteristiknya ke dalam suatu wadah yang lebih besar seperti drum yang dilengkapi bahan penyerap. Karakteristik ini dapat diketahui melalui telaah MSDS maupun piktogram pada etiket di badan kemasan. Jika keduanya tidak ada, maka dapat dilakukan uji cepat secara kualitatif di lapangan, seperti menggunakan indikator universal untuk pemeriksaan pH atau potassium starch paper untuk pemeriksaan sifat oksidator. Untuk memudahkan identifikasi, selain melekatkan simbol dan label limbah B3 pada kemasan, harus pula dibuat suatu packing list yang berisi daftar limbah bahan kimia dan reagen yang terdapat pada masing-masing drum.

Umumnya limbah laboratorium disimpan sementara di unit kerja yang menghasilkan hingga limbah tersebut siap untuk diangkut ke TPS. Jika kegiatan pengangkutan yang dilakukan melewati jalan umum, maka wajib memiliki izin dan rekomendasi pengangkutan limbah B3. Sebaliknya, jika tidak melewati jalan umum, maka pengangkutan tersebut tidak perlu memiliki izin/rekomendasi, namun tetap harus memenuhi ketentuan teknis pengangkutan limbah B3.

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Design of Effluent Treatment System for Leather Tanning Industry

INTRODUCTION

Since the Industrial Revolution in Great Britain during the period 1750 to 1850, industrialization is rife across the globe. Massive changes in industrial processes, from the original use of human labor and natural materials turned into using machines and synthetic chemicals, has given a profound impact on social, cultural, and economies around the world. One of the industries that experienced these changes is leather tanning industry.

Leather tanning industry is one of the oldest industries in the world that has been established since ancient civilizations. This industry is classified as labor-intensive industry and mostly operates in rural areas, providing economic empowerment to the local community. However, leather tanning industry also has negative impacts to the environment due to the use of hazardous chemicals on its production process, leading to the generation of hazardous waste. Not only polluting the environment and endanger the health of living beings, waste generation is also a distinct disadvantage for the industry itself because of the loss of some valuable raw materials, energy, and products. Therefore, this waste must be managed accordingly, not only to treat it, but also to reduce and prevent its generation.

The purpose of this article is to provide knowledge and information regarding the production process in the leather tanning industry, including its generated waste, environmental impact, cleaner production opportunities, as well as wastewater treatment technology. This article is written based on the study of literature in the form of textbooks, journals, articles, and websites.

HISTORY OF LEATHER TANNING INDUSTRY

Tanning is the process of treating skins and hides (a by-product of slaughter activities that can be processed into a wide range of end-products) of animals to produce leather. A tannery is the place where the skins are processed. Tanning hide into leather involves a process which permanently alters the protein structure of skin, making it more durable and less susceptible to decomposition, and also possibly coloring it. Before tanning, the skins are unhaired, degreased, desalted, and soaked in water over a period of 6 hours to 2 days.

The English word for tanning is from medieval Latin tannāre, derivate of tannum (oak bark), related to Old High German tanna meaning oak or fir (related to modern Tannenbaum). This refers to use of the bark of oaks (the original source of tannin) in some kinds of hide preservation. Ancient civilizations used leather for waterskins, bags, harnesses and tack, boats, armour, quivers, scabbards, boots, and sandals. Tanning was being carried out by the South Asian inhabitants of Mehrgarh between 7000 and 3300 BC. Around 2500 BC, the Sumerians began using leather, affixed by copper studs, on chariot wheels.

Formerly, tanning was considered a noxious or odoriferous trade and relegated to the outskirts of town, amongst the poor. Indeed, tanning by ancient methods is so foul smelling, tanneries are still isolated from those towns today where the old methods are used. Skins typically arrived at the tannery dried stiff and dirty with soil and gore. First, the ancient tanners would soak the skins in water to clean and soften them. Then they would pound and scour the skin to remove any remaining flesh and fat. Next, the tanner needed to remove the hair from the skin. This was done either by soaking the skin in urine, painting it with an alkaline lime mixture, or simply allowing the skin to putrefy for several months then dipping it in a salt solution. After the hair was loosened, the tanners scrapped them off with a knife. Once the hair was removed, the tanners would “bate” (soften) the material by pounding dung into the skin, or soaking the skin in a solution of animal brains. Bating was a fermentative process which relied on enzymes produced by bacteria found in the dung. Among the kinds of dung commonly used were those of dogs or pigeons. Sometimes, the dung was mixed with water in a large vat, and the prepared skins were kneaded in the dung water until they became supple from bacterial enzyme action, but not too soft. The ancient tanners might use their bare feet to knead the skins in the dung water, and the kneading could last two or three hours. This combination of urine, animal feces, and decaying flesh made ancient tanneries malodorous. Children employed as dung gatherers were a common sight in ancient cities. Also common were “piss-pots” located on street corners, where human urine could be collected for use in tanneries by washerwomen.

Historically the actual tanning process used vegetable tanning. In some variations of the process, cedar oil, alum, or tannin were applied to the skin as a tanning agent. As the skin was stretched, it would lose moisture and absorb the agent. Following the adoption in medicine of soaking sutures in a chromium(III) solution after 1840, it was discovered that this method could also be used with leather and thus was adopted by tanners.

Leather tanning industry is one of the industries in Indonesia that its development is strongly encouraged by the government as the non-oil and gas source of income. Leather tanning industries in Indonesia mostly operate in rural areas, providing economic empowerment to the local community. One of the centers of the leather tanning industry in Indonesia is located in the Ringinagung Village, Magetan Regent, East Java Province. Geographically, this village is adjacent to Candirejo Village in the north, Magetan Sub-district in the east, Sambirobyong Village in the west, and Sumber Dukun Village in the South. Small enterprises of leather tanning industry in this village has been started since 1830. Now, there is a place in this village, known as Lingkungan Industri Kecil, where the tanners are gather and collaborate with local government.

PROCESS

Tanning is essentially the reaction of collagen fibers in the hide with tannins, chromium, alum, or other chemical agents. “Leather tanning” is a general term for the numerous processing steps involved in converting animal hides or skins into finished leather.

Preparation

The actual tanning process begins with obtaining an animal skin. When an animal skin is to be tanned, the animal is killed and skinned before the body heat leaves the tissues. This can be done by the tanner, or by obtaining skin at a slaughterhouse, farm, or local fur trader. Preparing hides begins with curing them with salt. Curing is employed to prevent putrefaction of protein substrate (collagen) from bacterial growth during the time lag from procuring the hide to when it is processed. Curing removes water from the hides and skins using a difference in osmotic pressure. The moisture content of hides and skins is greatly reduced, and osmotic pressure increased, to the point that bacteria are unable to grow. In wet-salting, the hides are heavily salted, then pressed into packs for about 30 days. In brine-curing, the hides are agitated in a saltwater bath for about 16 hours.

Beamhouse Operation (Pre-tanning)

The steps in the production of leather between curing and tanning are collectively referred to as beamhouse operations. They include, in order, soaking, liming, removal of extraneous tissues (unhairing, scudding, and fleshing), deliming, bating (including puering), drenching, and pickling.

In soaking, the hides are soaked in clean water to remove the salt left over from curing and increase the moisture so that the hide or skin can be further treated. To prevent damage of the skin by bacterial growth during the soaking period, biocides, typically dithiocarbamates, may be used. Fungicides such as 2-thiocyanomethylthiobenzothiazole may also be added later in the process, to protect wet leathers from mold growth. After 1980, the use of pentachlorophenol and mercury-based biocides and their derivatives was forbidden.

After soaking, the hides and skins are taken for liming: treatment with milk of lime (a basic agent) that may involve the addition of “sharpening agents” (disulfide reducing agents) such as sodium sulfide, cyanides, amines, etc. the objectives of this operations are mainly to:

  • Remove the hair and other keratinous matter
  • Remove some of the interfibrillary soluble proteins such as mucins
  • Swell up and spill up the fibers to the desired extent
  • Remove the natural grease and fats to some extent
  • Bring the collagen in the hide to a proper condition for satisfactory tannage

The weakening of hair is dependent on the breakdown the of disulfide link of the amino acid cystine, which is the characteristic of the keratin class of proteins that gives strength to hair and wools (keratin typically makes up 90% of the dry weight of hair). The hydrogen atoms supplied by the sharpening agent weaken the cystine molecular link whereby the covalent disulfide bond links are ultimately ruptured, weakening the keratin. To some extent, sharpening also contributes to unhairing, as it tends to break down the hair proteins. The isoelectric point of the collagen in the hide (this is a tissue-strengthening protein unrelated to keratin) is also shifted to around pH 4.7 due to liming.

Unhairing agents used at this time include sodium sulfide, sodium hydroxide, calcium hydrosulfide, dimethyl amine, and sodium sulfhydrate. The majority of hair is then removed mechanically, initially with a machine and then by hand using a dull knife, a process known as scudding.

The pH of the collagen is brought down to a lower level so the enzymes may act on it, in a process known as deliming. Depending of the end use of the leather, hides may be treated with enzymes to soften them, a process called bating. In modern tanning, these enzymes are purified agents, and the process no longer requires bacterial fermentation (as from dung-water soaking) to produce them.

Once bating is complete, the hides and skins are treated first with salt and then with sulfuric acid, in case a mineral tanning is to be done. This is done to bring down the pH of collagen to a very low so as to facilitate the penetration of mineral tanning agent into the substance. This process is known as pickling. The common salt (sodium chloride) penetrates the hide twice as fast as the acid and checks the ill effect of sudden drop of pH.

Tanning Process

Chromium(III) sulfate ([Cr(H2O)6]2(SO4)3) has long been regarded as the most efficient and effective tanning agent. Chromium(III) compounds of the sort used in tanning are significantly less toxic than hexavalent chromium. Chromium(III) sulfate dissolves to give the hexaquachromium(III) cation, [Cr(H2O)6]3+, which at higher pH undergoes processes called olation to give polychromium(III) compounds that are active in tanning, being the cross-linking of the collagen subunits. The chemistry of [Cr(H2O)6]3+ is more complex in the tanning bath rather than in water due to the presence of a variety ligands. Some ligands include the sulfate anions, the collagen’s carboxyl groups, amine groups from the side chains of amino acids, and masking agents. Masking agents are carboxylic acids, such as acetic acid, use to suppress formation of polychromium(III) chains. Masking agents allow the tanner to further increase the pH to increase collagen’s reactivity without inhibiting the penetration of the chromium(III) complexes.

Collagen is characterized by a high content of glycine, proline, and hydroxyproline, usually in the repeat -gly-pro-hypro-gly-. These residues give rise to collagen’s helical structure. Collagen’s high content of hydroxyproline allows for significant cross-linking by hydrogen bonding within the helical structure. Ionized carboxyl group (RCO2) are formed by hydrolysis of the collagen by the action of hydroxide. This conversion occurs during the liming process, before introduction of the tanning agent (chromium salts). The ionized carboxyl groups coordinate as ligands to the chromium(III) centers of the oxo-hydroxide clusters.

Tanning increases the spacing between protein chains in collagen from 10 to 17 Å. The difference is consistent with cross-linking by polychromium species, of the sort arising from olation and oxolation. Prior to the introduction of the basic chromium species in tanning, several steps are required to produce a tannable hide. The pH must be very acidic when the chromium is introduced to ensure that the chromium complexes are small enough to fit in between the fibers and residues of the collagen. Once the desired level of penetration of chrome into the substances is achieved, the pH of the material is raised again to facilitate the process. This step is known as basification. In the raw state, chrome-tanned skins are blue, so are referred to as wet blue. Chrome tanning is faster than vegetable tanning (less than a day for this part of the process) and produces a stretchable leather which is excellent for use in handbags and garments.

Subsequent to application of the chromium agent, the bath is treated with sodium bicarbonate to increase the pH to 4.0-4.3, which induces cross linking between the chromium and the collagen. The pH increase is normally accompanied by a gradual temperature increase up to 40 oC. chromium’s ability to form such stable bridged bonds explains why it is considered one of the most efficient tanning compounds. Chromium tanned leather can contain between 4 and 5% of chromium. This efficiency is characterized by its increased hydrothermal stability of the skin, and its resistance to shrinkage in heated water.

Vegetable tanning uses tannins (a class of polyphenol astringent chemicals), which occur naturally in the bark and leaves of many plants. Tannins bind to the collagen proteins in the hide and coat them, causing them to become less water-soluble and more resistant to bacterial attack. The process also causes the hide to become more flexible. The primary bark processed in bark mills and used in modern times are chestnut, oak, redoul, tanoak, hemlock, quebracho, mangrove, wattle (acacia), and myrobalans from Terminalia spp., such as Terminalia chebula. Hides are stretched on frames and immersed for several weeks in vats of increasing concentration of tannin. Vegetable-tanned hide is not very flexible and used for luggage, furniture, footwear, belts, and other clothing accessories.

Tawing

Tawing is a method that uses alum and aluminum salts, generally in conjunction with other products such as egg yolk, flour, and other salts. The leather becomes tawed by soaking in a warm potash alum and salts solution, between 20 and 30 oC. The process increases the leather’s pliability, stretchability, softness, and quality. Adding yolk and flour to the standard soaking solution further enhances its fine handling characteristics. Then, the leather is air dried (crusted) for several weeks, which allows it to stabilize. Tawing is traditionally used on pigskins and goatskins to create the whitest colors. However, exposure and aging may cause slight yellowing over time and, if it remains in a wet condition, tawed leather will suffer from decay.

Depending on the finish desired, the hide may be waxed, rolled, lubricated, injected with oil, split, shaved, and dyed. Suedes, nubucks, etc. are finished by raining the nap of the leather by rolling with a rough surface.

The first stage is the preparation for tawing. The second stage is the actual tawing and other chemical treatment. The third stage, known as retawing, applies retawing agents and dyes to the material to provide the physical strength and properties desired depending on the end product. The fourth and final stage, known as finishing, is used to apply finishing material to the surface or finish the surface without the application of any chemicals if so desired.

ENVIRONMENTAL PROBLEMS FROM LEATHER TANNING INDUSTRY

The production processes of leather tanning have a high environmental impact, most notably due to:

  • the heavy use of polluting chemicals in the tanning process, and
  • air pollution due to the transformation process (hydrogen sulfide during unhairing and ammonia during deliming, solvent vapors).

One tone of hide or skin generally leads to the production of 20 to 80 m3 of turbid and foul-smelling wastewater, including chromium levels of 1000 – 400 mg/l, sulfide levels of 200 – 800 mg/l, and high levels of fat and other solid wastes, as well as notable pathogen contamination. Pesticides are also often added for hide conservation during transport. With solid wastes representing up to 70% of the wet weight of the original hides, the tanning process comes at a considerable strain on water treatment installations. The following table on the overleaf shows the example of mass balance of chemicals and average total pollution from the leather tanning production process.

Kanpur, India stands as a prime example of how tannery chemicals and wastewater can negatively affect health and ecosystems. In 2013, the city became the largest exporter of leather. About 80% of the wastewater is untreated and dumped straight into Kanpur’s main water source, the River Ganges. Farmland is swamped with blue-tinted water, poisoned with chromium(III), lead, and arsenic. Decades of contamination in the air, water, and soil have caused a variety of diseases in the people who live in the area. Health problems include asthma, eyesight problems, and skin problems include: contact dermatitis, urticaria, hand eczema, fungal infection, and atopic eczema.

Boiling and sun drying can oxidize and convert the various chromium(III) compounds used in tanning into carcinogenic hexavalent chromium, or chromium(VI). This hexavalent chromium runoff and scraps are then consumed by animals, in the case of Bangladesh, chickens (the nation’s most common source of protein). Up to 25% of the chickens in Bangladesh contained harmful levels of hexavalent chromium, adding to the national health problem load.

Chromium is not solely responsible for these diseases. Methyl isothiazolinone, which is used for microbiological protection (fungal or bacterial growth), causes problems with the eyes and skin. Anthracene, which is used as a leather tanning agent, can cause problems in the kidneys and liver and is also considered a carcinogen. Formaldehyde and arsenic, which are used for leather finishing, cause health problems in the eyes, lungs, liver, kidneys, skin, and lymphatic system and are also considered carcinogens. The waste from leather tanneries is detrimental to the environment and the people who live in it. The use of old technologies plays a large factor in how hazardous wastewater results in contaminating the environment. This is especially prominent in small and medium-size tanneries in developing countries.

Wastewater

Water will not only have a diluting effect, it also increases the number of kg of BOD per ton of hides. According to David Winter (1984), there is a downward trend in water consumption from year to year in leather tanning production process; 103 l/kg of raw hide in 1962, 71 l/kg in 1975, and 40 l/kg in 1977. David Winter (1984) and Clonfero (1987) tend to prefer the use of water as much as 45 l/kg of raw hide.

Wastewater generated from leather tanning industries mostly contains 9 groups of pollutants, i.e. pathogens, biodegradable organic pollutants, non-biodegradable organic pollutants, sediment, colloid, floating materials, heavy metals, soluble inorganic pollutants, and acid-base.

In general, wastewater generated from leather tanning industries has characteristics as follows:

  • Irregular effluent discharge.
  • Greenish blue color from the use of chromium(III)
  • Foamy
  • Containing high level of sulfide, suspended solids, and organic matters
  • Varies pH (between 3 and 12)
  • Septic

Every leather tanning process step, with exception of the crust finishing operations, produces wastewater.

Solid Waste

According to Buljan (1994), the solid waste produced per ton of raw hide is about 450 – 600 kg, comprised of trimming, fleshing, wet blue split, and buffing dust. About half of this contains 3% of chrome on a dry matter basis.

Air Pollution

An important part of the air pollution by leather tanneries is caused by the need for energy. In 1992, the Dutch National Institute for Public Health and the Environment (RIVM) estimated the need for the Dutch tanneries at 439 kWh of electricity per ton of raw hides and 108 m3 of gas per ton of raw hides for heating. The use of organic solvents and dyes also cause emissions into the air.

CLEANER PRODUCTION POTENTIAL OF LEATHER TANNING INDUSTRY

Water Conservation

A reduction of water use can lead to a reduction of the total waste load. Re-use of wastewater with a minimal harmful or even a moderately beneficial effect on earlier processes may be considered as an option.

Curing Hides and Skins

A reduction of the use of salt for preservation can be considered as an option. 15% of salt (w/w) may preserve the hides for even 6 weeks, and 5% (w/w) of salt plus biocide lead to a preservation for 2 months. Chilling at very low temperatures can also preserve the hides and skins for a few days. Another alternative preservation method is radiation by electron beam or gamma rays. Where possible, biodegradable preservatives should be used instead of derivatives of chlorinated aromatic hydrocarbons due to their persistence in the waste and toxic characteristics.

Beamhouse Processes

Hair saving methods are recommended to prevent degraded keratin from entering the waste streams. Unhairing/liming fluids can be recycled after recharging. It is also recommended that the unhairing and liming stages should be separated. Both liquids can be recharged and hair can be screened out. The intermediate wash can be re-used as a soak liquid.

Tanning Process

Alternative mineral salts such as alum, zirconium, titanium, iron salts, or a combination thereof, might be used as substitutes for chromium salts, producing wet white leather which more ecofriendly than the wet blue leather produced from chrome tanning. However, under certain conditions aluminum is known to be more poisonous to aquatic life than chromium(III) and even hexavalent chromium. Re-use of chromium is a more realistic alternative. The unused tanning fluids which contain chromium can be collected separately. From these fluids and from the solids that contain chromium, chromium can be recovered. The remainder may be used as source material for glue and animal feedstuff. In countries where discharge of chromium is strictly prohibited, great efforts are made to recover and re-use chrome.

Alternative vegetable tanning methods can also replace chrome tanning to a high degree. An example is the Liritan process, developed in South Africa. A high chemical uptake, low pollution load, uniform penetration of the tan and a shortened process time with consequent financial efficiency are claimed to be the main advantages of this process, but little is known on the practical implications.

Finishing

A reduction of volatile organic compounds (VOC) can be accomplished by using aqueous finishes for base and middle finishing coatings.

WASTEWATER TREATMENT TECHNOLOGY FOR LEATHER TANNING INDUSTRY

Wastewater treatment is a multi-stage process to purify wastewater before it enters a body of natural water, or it is applied to the land, or it is reused. The goal is to reduce or remove organic matter, solids, nutrients, chrome, and other pollutants since each receiving body of water can only receive certain amounts of pollutants without suffering degradation. Therefore, each effluent treatment plant must adhere to discharge standards – limits usually promulgated by the relevant environmental authority as allowable levels of pollutants, for practical reasons expressed as BOD5, COD, suspended solids (SS), Cr, total dissolved solids (TDS) and others. The three main categories of tannery wastewater, each one having very distinctive characteristics, are:

  • Effluents emanating from the beamhouse operation – liming, deliming/bating, water from fleshing and splitting machines; they contain sulfides, their pH is high, but they are chrome-free.
  • Effluents emanating from the tannyard (tanning) – high chrome content, acidic.
  • Soaking and other general effluents, mainly from tawing operations (fat-liquoring, dyeing) – low chrome content.

It is very important to segregate these streams and to pre-treat them separately according to their characteristics to avoid possible safety risks (formation of deadly hydrogen sulfide) and to reduce the cost of treatment and sludge disposal (to avoid contamination of sludge with chrome). The mixing of liming and tanning streams gives rise not only to the obnoxious smell typical of poorly managed tanneries; the resulting lethally poisonous gas, hydrogen sulfide (H2S), is still by far the most frequent killer in tannery accidents, which occur mainly in inadequately ventilated spaces, especially in pits and channels.

In general, wastewater treatment process comprised of a series of stages viz. preliminary treatment, primary treatment, secondary treatment, tertiary treatment, and sludge handling/disposal. Each stage has its own role in treating the wastewater. In field application, preliminary treatment is mostly combined together with primary treatment due to their correlate functions to prepare the wastewater before entering the main system, i.e. secondary treatment. Tertiary treatment employs advanced and sophisticated technology and is only an optional process for further treatment of the effluent. And similar with other processes, wastewater treatment also generates residue in the form of sludge that must be handled and disposed accordingly.

Preliminary and Primary Treatment

This stage mostly employs physical process and chemical processes to treat the wastewater. The objectives of preliminary and primary treatment are as follows:

  • To eliminate the coarse material normally present in the raw wastewater that could clog/block pumps, pipes, and possibly sewer lines.
  • To mix and balance well different tannery streams and thus produced homogenized raw material that can be treated in a consistent manner.
  • To adjust pH and eliminate toxic substances (sulfides) and avoid shock loads that can negatively the rather sensitive biological treatment.
  • To significantly decrease the BOD/COD load and thus simplify the biological treatment phase and reduce its cost.
  1. Bar Screening. Bar screening removes large particles and sand/grit.
  2. Pumping. It is not possible to transfer effluents throughout the ETP by gravity only; at least one, often more pumping/lifting stations are needed, the first typically located before the rotary screen. Depending on specific requirements (capacity/flow), different types of pumps are used. For medium-scale ETPs, submersible pumps are generally used for this purpose, for large-volume ones, screw (Archimedes) pumps are preferred.
  3. Fine screening. Fine screening should drastically reduce the amount of fine suspended solids.
  4. Equalization and Sulfide Oxidation. The main aims of this stage are to homogenize the effluent (quality and quantity), and eliminate sulfide, mostly by catalytic oxidation. It is very important to keep all particulate matters in suspension, i.e., to avoid settling of solids. This is achieved by using mixing-cum-aeration devices such as diffused-air systems, Venturi ejectors, and fixed or floating aerators. In practice, the volume of the equalization tank corresponds to the total daily effluent discharge. Approximately 1 kg of O2 is needed to oxidize 1 kg of S2- to thiosulphate, whereas the oxygen transfer efficiency is about 1.5 kg O2/kWh (simplified approximation: 1 kg S2- = 1 kg O2 = 1kWh). Attention is focused on the energy required to keep the solids in suspension (some 50 W/m3), which is then sufficient for sulfide oxidation; the amount of catalyst, MnSO4.4H2O, industrial purity, is about 20 g per cubic meter of tank capacity. The mixing/aeration system must be possible to be removed without stopping the treatment process. The inlet and the outlet of the equalization tank should be as far away from each other as possible to allow proper mixing and no short-circuiting. A typical equalization tank will have transfer pumps for equalized effluent. The capacity of the pumps is based on tank capacity, transfer time and head. One pump of cast iron with inside parts of stainless steel and one stand-by pump are sufficient unless effluent volume is very high (ca. 1500 m3/d or more). The pumping lines are also a good place to set an electro-magnetic flow meter.
  5. Coagulation/Flocculation. Chemicals are added in order to improve and accelerate the settling of suspended solids, especially of fine and colloidal matter. In wastewater treatment operations, the processes of coagulation and flocculation are employed to separate suspended solids from water. Coagulation is the destabilization of colloids by neutralizing the forces that keep them apart. Cationic coagulants provide positive electric charges to reduce the negative charge (zeta potential) of the colloids. As a result, the particles collide to form larger particles (flocs). Rapid mixing is required to disperse the coagulant throughout the liquid. Care must be taken not to overdose the coagulants as this can cause a complete charge reversal and thus re-stabilize the colloid complex. Flocculation is the action of polymers to form bridges between flocs and bind particles into large agglomerates or clumps. In this process, it is essential that the flocculating agent be added by slow and gentle mixing to allow for contact between the small flocs and to agglomerate them into larger particles. The newly formed agglomerated particles are quite fragile and can be broken apart by shear forces during mixing. Care must also be taken not to overdose the polymer as doing so will cause settling/clarification problems. Once suspended particles are flocculated into larger particles, they can usually be removed from the liquid by sedimentation, filtration, straining or floatation. The flocculation reaction not only increases the size of floc particles in order to settle them faster, but also affects the physical nature of flocs making them less gelatinous and thereby easier to dewater. The inorganic coagulants are compounds that break colloidal suspensions and help floc forming. The most frequently used coagulants in tannery effluent treatment are: alum sulfate (Al2(SO4)3.18H2O), iron sulfate (FeSO4.7H2O), iron chloride (FeCl3.6H2O), and calcium hydroxide (Ca(OH)2). Flocculants are water-soluble organic (anionic) polyelectrolytes that support agglomeration of colloidal and very fine suspended matter thus enhancing the impact of coagulation. Chemicals dissolved in small tanks with stirrers are usually added in the flash mixers. The contact time in the flash mixer is about 5 minutes for coagulation and some 20 minutes for flocculation; in the latter case, slow mixing to avoid floc shearing is essential. Ideally, two tanks should be available for the preparation of each chemical; one for solution preparation, the other for feeding the solution to the effluent. By having two tanks, levels of chemical dosing can be better controlled. The feeding of chemicals is done by dosing pumps.
  6. Settling (Primary Settling). The main objective at this stage is the removal of suspended solids; however, various constituents such as fats, waxes, mineral oils, floating non-fatty materials, etc., not already removed in the grit and oil chamber, are also separated here. Primary settling tanks (clarifiers) are either circular or rectangular with continuous grease (scum) removal at the top and sludge removal at the bottom. The surface solids rate is most frequently used in the design of sludge thickeners but, due to the quantity (4-6 g/l) and flocculent nature of tannery effluent solids, it is useful in controlling the primary sedimentation as well. Circular tanks are generally preferred as recirculation is easier. A mechanical device (scraper) is necessary in larger settling tanks. In some cases, mainly due to space shortage, solids are removed by flotation, usually by the dissolved-air flotation (DAF) system.

Secondary Treatment

Secondary treatment employs biological process to treat the wastewater. The main objective at this stage is to further reduce the amount of organic (expressed as BOD and COD) and other substances still present in the effluent after the primary treatment and thereby satisfy the standards/limits for discharge into water body recipient.

Due to the sulfide/sulfate content of the tannery effluent which leads to the formation of highly toxic corrosive, and flammable H2S gas, aerobic process is then the most suitable method for the secondary treatment of leather tanning wastewater. Among many variations of the aerobic process, the most widely used method is activated sludge treatment with extended aeration. The activated sludge process is an aerobic, biological process, which uses the metabolism of microorganisms to remove substances causing oxygen demand. The microbial community that does that job comprises various species of bacteria, fungi, protozoa, sometimes rotifers (multicellular animals only found in very stable activated sludge with long retention times), even nematodes, the composition of the population depending on a plethora of factors.

The possibly best biological treatment of tannery effluents is the oxidation ditch (OD) and its various derivatives – a circular aeration basin (racetrack-shaped), with rotary-brush or vertical-rotor (carrousel) aerators that extend across the width of the ditch. In addition to its simple construction and easy maintenance, the main advantage of the OD is its resilience to variations in flow, pollution load, including shock loads. It is even possible to combine several ovals and maintain different aeration regimes suitable for nitrification and denitrification.

  1. Aeration Devices. Aeration is an important factor that employs a wide range of equipment. In addition to cost, reliability, etc., the key criterion is the amount of air (oxygen) transfer per kW installed. Oxidation ditch (OD) systems mostly use surface aerators with brush rotor.
  2. Secondary Settling. The design is very similar to the primary sedimentation unit, but the operational conditions are different. Also, the sludge evacuated at the tank bottom is normally bulkier and more difficult to dewater. In secondary sedimentation of tannery effluent, surface overflow rate (SOR) of approximately 0.5 m3/m2 per hour is generally used, while surface solid rate (SSR) values used are generally between 2.0 and 3.0 kg/m2 per hour. SOR is the vertical velocity of the influent in the secondary sedimentation tank, SSR is the quantity per hour of MLSS (kg) crossing the surface area of the secondary sedimentation tank.

Generally, the biological stage is the most complex part of the overall effluent treatment process, with highest investment and operational costs, its day-to-day running requiring considerable skills and experience. In order to keep the microorganisms in the system alive, performing their role to treat the wastewater, several operational parameters must be monitored and controlled as follows:

  1. Total influent volume (Q) – a uniform inlet flow over the entire day provides optimum conditions for absorbing the effect of possible peaks of organic load or toxic substances (shock loads) and enhancing the efficiency of secondary sedimentation.
  2. Organic loading (F) – is the total BOD5 The BOD here is in practice taken to represent the amount of food provided to the micro-organisms contained in the system. Due to the difficulty of obtaining reliable BOD5 values, COD is sometimes used.
  3. Mixed liquid suspended solid (MLSS) – is the concentration of SS in mixed liquor in the aeration tank.
  4. Loading factor (F/M) – is the food to biomass (floc) ratio. It is a crucial parameter for operational conditions and the performance of the biological process; regrettably, it cannot be determined quickly, on-the-spot. The actual F/M can be obtained after the system operates normally.
  5. Hydraulic retention time (T) – is actually the average time (in hours) the influent spends passing through the aeration tank; the extended aeration process, typical for tannery effluents, is usually longer than 24 hours.
  6. Dissolved oxygen (DO) – is he content of molecular oxygen in the aeration tank (mg/l); it is one of the most important factors determining the efficiency or performance of wastewater biological treatment. Extended aeration units are usually operated in such a way as to keep the DO of the mixed liquor at about 2 mg/l.
  7. pH – the optimum pH range for aerobic processes is between 7.0 and 7.5 with an effective process range of 6-9. In alkaline wastes, the reaction with CO2 produced by respiration neutralizes the excess alkali, making addition of acid unnecessary. Adjustment with lime or other alkali becomes necessary only if pH drops below 6.
  8. Temperature – affects the metabolic and growth rates of the organisms responsible for the biological processes. Generally, as the temperature is raised 10-30°C, the growth rate increases. However, higher temperature negatively affects the water solubility of oxygen and the oxygen transfer rate (solubility decreases with a rise in temperature). For this reason, an increase of the aeration rate becomes necessary during the hot season.
  9. Nutrients – the nutritional balance of an aerobic system is primarily based upon satisfying the requirements of the cell structure produced by the removal of BOD from waste. Efficient and successful biological oxidation requires a minimal quantity of nitrogen and phosphorus. A BOD : N : P ratio of 100 : 5 : 1 in the waste usually insures adequate nutrition. Tannery effluent is very rich in nitrogen and sometimes poor in phosphorus.
  10. Sludge volume index (SVI) – is the volume occupied by 1 g of activated sludge after settling the aerated mixed liquor in a 1000 ml graduated cylinder or Imhoff cone for 30 minutes. It provides a good indication of sludge compacting characteristics, very helpful in controlling the activated sludge process, especially in determining return sludge pumping requirements to maintain different mixed-liquor concentrations. Well settleable and mineralized sludges have SVI <100.

Advanced Treatment

In certain cases, despite extensive physical-chemical and biological treatment in a well-designed ETP, the quality of the final effluent does not meet the promulgated discharge limits. The usual culprit is the recalcitrant COD, i.e., compounds that the micro-organisms present in the floc are unable to decompose. In such cases, it is necessary to resort to additional, usually more sophisticated and rather expensive treatments such as mineralization of organic compounds by oxidation with H2O2 in the presence of ferrous sulfate (Fenton process and its derivatives). Ozonation is sometimes included not so much to kill potentially harmful micro-organisms but to destroy part of the residual COD.

Sludge Handling and Disposal

For further handling and disposal of sludge, it is necessary to reduce drastically the water content. The main purpose of sludge dewatering is not only to reduce the volume and weight of material to be transported but also to attain the dry matter content required for disposal at landfills.

  1. Sludge Thickening. Sludge thickening is a process to increase the solid content of the sludge by removing a portion of the liquid fraction. By increasing the solid content, more economical treatment of the sludge can be effected. Gravity thickening is a common method of sludge thickening applied in tannery effluent treatment system due to its suitability for primary sludge and secondary sludge generated from activated sludge system. Equipment used for gravity thickening consists of a thickening tank, which is similar in design to the settling tank used in primary treatment. In operation, solid is withdrawn from primary and secondary treatment and pumped to the thickener. The solids buildup in the thickener forms a solid blanket on the bottom. The weight of the blanket compresses the solid on the bottom and squeezes the water out. By adjusting the blanket thickness, the percent of solid in the underflow can be increased or decreased. The supernatant that rises to the surface is returned to the wastewater flow for treatment.
  2. Pressurized Filtration. To maximize the liquid removal, thickened sludge from gravity thickener is treated using plate-and-frame filter press, also known as chamber filter press. This method is commonly used to achieve high dry solid (DS) sludge cakes. In operation, sludge is pumped between plates. Pressure (200 – 250 psi) is applied to the plates and liquid is squeezed from the sludge. At the end of the cycle, the pressure is released and as the plates separate the cakes drop out onto a conveyor belt for transport to storage or disposal.
  3. Sludge Drying Beds. Easily constructed with locally available materials, drying beds were perceived as the best solution for tanneries in hot-climate developing countries. However, they require a lot of area, the output during rainy seasons drops considerably, there is the problem of malodor, they are not easy to clean and made ready for the next batch, etc., thus it is only an optional.
  4. Utilization and Disposal. In comparison with sanitary sludges, tannery sludge has greater inorganic matter content, greater heavy metal content, especially chromium and greater sulfur compound content. However, the main stumbling block is the chromium content, with legislation and practice varying a lot from country to country. In Indonesia, sludge generated from the ETP of leather tanning industry is classified as hazardous waste, thus strictly regulated and must be managed accordingly. In most cases, tannery sludge in Indonesia is safely disposed into the hazardous waste landfill operated by PT Prasadha Pamunah Limbah Industri, the largest and pioneer industrial waste management facility.

REFERENCES

  1. Introduction to Treatment of Tannery Effluents: What Every Tanner Should Know about Effluent Treatment, UNIDO, 2011.
  2. Sludge Management: Waste or A Resource, S. Veenstra, International Institute for Infrastructural, Hydraulic and Environmental Engineering, 1999.
  3. Handbook of Water and Wastewater Treatment Plant Operations, F.R. Spellman, Lewis Publishers, 2003.
  4. https://keslingmks.wordpress.com/2008/08/18/industri-penyamakan-kulit-dan-dampaknya-terhadap-lingkungan/
  5. https://en.wikipedia.org/wiki/Tanning_(leather)
  6. https://en.wikipedia.org/wiki/Leather_production_process
  7. http://www.mastrotto.com/tanning-process/
  8. fao.org/wairdocs/lead/x6114e05.htm
  9. http://www3.epa.gov/ttnchie1/final

Dasar-dasar Penyusunan AMDAL

Setiap kegiatan pembangunan pasti selalu diikuti oleh dampak positif dan negatif, sehingga perlu dilakukan kajian secara cermat dan komprehensif guna memaksimalkan dampak positif dan meminimalisir dampak negatif. Salah satu bentuk kajian ini adalah analisis mengendai dampak lingkungan hidup (AMDAL). AMDAL adalah sistem pengelolaan lingkungan yang pertama kali berkembang di Amerika Serikat. Sistem ini kemudian diadopsi oleh sejumlah negara, termasuk Indonesia, dan dikembangkan sesuai dengan kebutuhan dan kondisi masing-masing negara. Di Indonesia, AMDAL diterapkan sebagai instrument pengelolaan dan pengendalian dampak lingkungan, sekaligus sebagai salah satu syarat permohonan izin dari suatu rencana usaha dan/atau kegiatan.

 

Sebagai salah satu bentuk kajian ilmiah, AMDAL memiliki peran strategis dalam pengelolaan setiap pembangunan dan wajib dilaksanakan karena tercantum dalam UU No. 32/2009 tentang Pengelolaan dan Perlindungan Lingkungan Hidup Pasal 22. Berdasarkan regulasi, kegiatan yang wajib memiliki AMDAL adalah kegiatan yang berpotensi menimbulkan dampak penting terhadap lingkungan, antara lain:

 

  1. Pengubahan bentuk lahan dan bentang alam
  2. Eksploitasi sumber daya alam, baik yang terbarukan maupun tak terbarukan
  3. Proses dan kegiatan yang secara potensial dapat menimbulkan pemborosan, pencemarann dan kerusakan lingkungan hidup, serta kemerosotan sumber daya alam dalam pemanfaatannya
  4. Proses dan kegiatan yang hasilnya dapat mempengaruhi lingkungan alami, lingkungan buatan, serta lingkungan sosial budaya
  5. Proses dan kegiatan yang hasilnya akan mempengaruhi kawasan konservasi sumber daya alam dan/atau perlindungan cagar budaya
  6. Introduksi jenis tumbuh-tumbuhan, jenis hewan, dan jasad renik
  7. Pembuatan dan penggunaan bahan hayati dan non-hayati
  8. Penerapan teknologi yang diperkirakan mempunyai potensi besar untuk mempengaruhi lingkungan hidup
  9. Kegiatan yang mempunyai risiko tinggi dan/atau mempengaruhi pertahanan negara

 

AMDAL merupakan suatu kajian ilmiah multi disiplin yang terdiri dari kajian teknis (biologi, fisika, kimia, ekologi, dan geologi), kajian ekonomi, dan kajian sosial budaya. Sebagai suatu kajian ilmiah, penyusunan AMDAL dilakukan melalui serangkaian tahapan agar menghasilkan suatu hasil yang berkualitas dan dapat dipertanggungjawabkan. Dokumen AMDAL terdiri dari KA-ANDAL, ANDAL, dan RKL-RPL, dengan tahapan penyusunan sebagai berikut:

 

  1. Publikasi dan sosialisasi. Tahapan ini dilakukan untuk menjaring saran, pendapat, dan tanggapan sebanyak-banyaknya dari masyarakat di sekitar lokasi rencana usaha dan/atau kegiatan, termasuk bila terdapat konflik pemanfaatan lokasi dan bentuk keluhan lainnya. Hal ini sesuai dengan PermenLH No. 17/2012 tentang Pedoman Keterlibatan Masyarakat dalam Proses AMDAL dan Izin Lingkungan. Kegiatan publikasi dan sosialisasi ini dapat dilakukan melalui penyebaran informasi via media massa, leaflet, papan pengumuman di dekat lokasi rencana usaha dan/atau kegiatan, atau bentuk sosialisasi lainnya.

 

  1. Pelingkupan. Tahapan ini merupakan suatu proses awal untuk menentukan lingkup permasalahan dan mengidentifikasi secara hipotesis dampak penting yang terkait dengan rencana usaha dan/atau kegiatan.

 

  1. Penyusunan kerangka acuan analisis dampak lingkungan hidup (KA-ANDAL). Tahapan ini bertujuan untuk merumuskan lingkup dan kedalaman kajian, serta mengarahkan kajian agar berjalan efektif dan efisien sesuai dengan biaya, tenaga, dan waktu yang tersedia. Dokumen ini berisi tentang latar belakang dan tujuan rencana usaha dan/atau kegiatan, informasi pemrakarsa dan penanggung jawab rencana usaha dan/atau kegiatan serta tim penyusun dokumen AMDAL, deskripsi rencana usaha dan/atau kegiatan yang akan dikaji, deskripsi rona lingkungan hidup awal, hasil pelibatan masyarakat, dampak penting hipotetik, batas wilayah kajian, batas waktu kajian, dan metode kajian yang digunakan. Dokumen KA-ANDAL ini nantinya akan dinilai oleh Komisi Penilai AMDAL untuk menentukan disetujui atau tidaknya kajian; jika disetujui, maka kajian dapat dilanjutkan.

 

  1. Penyusunan analisis dampak lingkungan (ANDAL). Kegiatan ini dilakukan setelah KA-ANDAL disetujui oleh Komisi Penilai AMDAL. Tujuan penyusunan ANDAL ialah untuk menyampaikan kajian secara cermat dan mendalam tentang dampak penting suatu rencana usaha dan/atau kegiatan. Hasil kajian ini nantinya dipergunakan untuk memberikan pertimbangan dalam pengambilan keputusan terkait layak/tidaknya suatu rencana usaha dan/atau kegiatan yang diusulkan. Dokumen ini antara lain memuat ringkasan deskripsi rencana usaha dan/atau kegiatan, dampak penting hipotetik, batas wilayah kajian, batas waktu kajian, metode kajian yang digunakan, deskripsi rinci rona lingkungan hidup awal, prakiraan dampak penting, dan evaluasi secara holistik terhadap dampak lingkungan,

 

  1. Penyusunan dokumen RKL-RPL. Tahapan ini merupakan perumusan rencana pengelolaan lingkungan hidup (RKL) melalui berbagai rekayasa teknologi atau lingkungan agar dapat meminimalisir dampak, serta penyusunan rencana pemantauan lingkungan (RPL) yang memuat bagaimana kegiatan pemantauan lingkungan dilakukan berdasarkan prediksi yang telah disusun. Kedua dokumen ini dibuat dalam bentuk matriks.

 

  1. Diskusi dan asistensi. Tahapan ini dilakukan pada saat penyusunan KA-ANDAL, ANDAL, dan RKL-RPL.

 

  1. Legalisasi dokumen. Tahap ini merupakan akhir dari rangkaian kegiatan penyusunan dokumen AMDAL yang dilakukan oleh instansi yang berwenang.

 

Peran Teknik Kimia dalam Bidang Lingkungan

Semakin maraknya kasus pencemaran lingkungan yang terjadi dewasa ini membuat bidang lingkungan menjadi satu isu global tersendiri. Kepedulian dan kesadaran yang semakin meningkat membuat masyarakat sebagai konsumen menuntut haknya atas kualitas lingkungan hidup yang baik. Isu lingkungan saat ini sudah menyentuh berbagai aspek kehidupan, termasuk juga industri. Pada dasarnya isu lingkungan bukan merupakan aspek utama dalam kegiatan industri, namun jika aspek lingkungan ini bermasalah maka akan berdampak besar bagi industri itu sendiri, seperti tidak dapat menjual dan mengekspor produknya, bahkan bisa berakibat penghentian operasional industri tersebut secara paksa oleh Pemerintah.

Sebagai bidang ilmu yang berkaitan erat dengan industri, teknik kimia memiliki peran penting dalam upaya menjaga kelestarian lingkungan. Secara sempit, peran teknik kimia dalam bidang lingkungan akan langsung diasosiasikan dengan lingkup pengelolaan limbah, khususnya pada pengolahannya, karena memang area inilah yang paling identik dengan aplikasi teknik kimia dalam bidang lingkungan. Contoh nyatanya adalah pada pengoperasian unit IPAL di industri yang umumnya dipegang oleh para insinyur kimia. Namun sebenarnya peran teknik kimia dalam bidang lingkungan lebih luas dari itu. Seiring dengan meningkatnya kesadaran masyarakat akan perlindungan lingkungan, saat ini lingkup pengelolaan limbah juga melibatkan upaya pengurangan timbulan limbah. Oleh sebab itu, dengan pengetahuan dan keahlian rekayasa proses yang dimilikinya, insinyur kimia seharusnya mampu memodifikasi suatu proses produksi sehingga berjalan lebih optimal dan menghasilkan sesedikit mungkin timbulan limbah, serta menghasilkan produk yang ramah lingkungan dan bernilai tinggi bagi masyarakat.

Untuk dapat berkiprah dan berprofesi dalam bidang lingkungan dengan baik, tentu saja insinyur kimia harus memiliki pengetahuan yang komprehensif dalam bidang teknis. Ilmu kimia, neraca massa dan energi, kinetika, termodinamika, unit operasi dan unit proses adalah modal dasar bagi insinyur kimia dalam menjalankan profesinya dalam bidang apapun, termasuk bidang lingkungan. Di sisi lain, karena dampaknya yang sangat luas, maka segala kegiatan yang dilakukan oleh industri yang terkait dengan lingkungan diatur ketat oleh regulasi. Regulasi di bidang lingkungan inipun sangat dinamis sesuai dengan perkembangan ilmu pengetahuan dan teknologi serta isu lingkungan, baik di dalam maupun luar negeri. Oleh sebab itu, insinyur kimia juga harus memiliki pengetahuan yang baik tentang regulasi lingkungan dan perkembangannya.

Pembuangan Limbah B3

Pembuangan limbah B3 (hazardous waste disposal) secara bebas dapat diartikan sebagai kegiatan menyingkirkan dan menghancurkan limbah B3. Kegiatan ini merupakan tahap terakhir dari lingkup kegiatan pengelolaan limbah B3. Berdasarkan Basel Convention, kegiatan ini meliputi pengolahan, pemanfaatan dan penimbunan akhir limbah B3. Dalam implementasinya, masing-masing negara yang meratifikasi Basel Convention memiliki “cara” tersendiri dalam menginterpretasikan dan melaksanakan pembuangan limbah B3 ini. Sebagai contoh, di Amerika Serikat kegiatan pembuangan limbah B3 ini dibagi menjadi dua kegiatan, yaitu pengolahan atau treatment yang mencakup juga kegiatan daur ulang limbah B3 untuk dimanfaatkan, dan penimbunan yang tetap menggunakan istilah disposal. Sedangkan di Indonesia kegiatan pembuangan limbah B3 dibagi menjadi tiga, yaitu pengolahan (treatment), pemanfaatan (utilization) dan penimbunan (disposal) yang mengacu pada kegiatan pembuangan limbah B3 Australia.

Outlet dari kegiatan pembuangan limbah B3 adalah lingkungan itu sendiri, sehingga akan berdampak terhadap kualitas lingkungan itu sendiri termasuk interaksi makhluk hidup di dalamnya. Oleh sebab itu kegiatan pembuangan limbah B3 harus dilakukan dengan baik dan benar serta memperoleh izin dari Pemerintah seperti halnya kegiatan pengelolaan limbah lainnya.

Pengolahan Limbah B3

Pengolahan limbah B3 merupakan kegiatan yang bertujuan untuk menghilangkan atau setidaknya menurunkan sifat bahaya dari suatu limbah B3. Pengolahan limbah B3 tidak menghilangkan polutan yang terkandung di dalamnya, melainkan menurunkan konsentrasinya hingga mencapai baku mutu yang aman untuk dilepas ke lingkungan yang ditetapkan oleh Pemerintah.

Pengolahan limbah B3 dapat dilakukan dengan metode fisika, kimia, biologi, termal, ataupun kombinasi dari keempatnya, dengan berdasarkan pada karakteristik limbah yang akan diolah. Masing-masing metode inipun memiliki kelebihan dan kekurangannya sendiri-sendiri. Metode fisika umumnya paling sederhana, namun kurang mampu memenuhi baku mutu secara cepat dan signifikan karena tidak dapat menghilangkan kandungan polutan dalam limbah; pengolahan dengan metode fisika hanya mengubah bentuk suatu limbah B3 sehingga lebih mudah untuk dikelola lebih lanjut. Pengolahan dengan metode kimia umumnya mampu memenuhi baku mutu secara cepat dan signifikan, namun dalam beberapa kasus justru menghasilkan suatu matriks yang memiliki massa dan volume lebih besar dari pada limbah asalnya karena adanya penggunaan bahan kimia sebagai reagen. Tidak jarang pula reagen yang digunakan merupakan bahan kimia berbahaya seperti asam kuat dan oksidator, sehingga memerlukan pengendalian khusus dalam prosesnya. Pengolahan dengan metode biologi relatif lebih aman untuk dilakukan karena umumnya diaplikasikan pada limbah-limbah yang mudah terurai dan tidak mengandung polutan yang sangat berbahaya, namun prosesnya sangat sensitif di mana kondisi lingkungan harus dijaga dengan baik agar mikroorganisme yang digunakan dapat tetap hidup. Pengolahan dengan metode termal secara umum merupakan yang paling praktis digunakan karena mampu mengurangi massa dan volume limbah secara signifikan serta memerlukan lahan yang tidak terlalu luas. Namun metode ini masih cukup mahal dan memerlukan tenaga ahli khusus untuk mengoperasikannya.

Pemanfaatan Limbah B3

Pada dasarnya pemanfaatan limbah B3 merupakan kegiatan pengolahan limbah B3 yang bertujuan untuk mengubah bentuk limbah B3 menjadi suatu produk yang dapat dimanfaatkan. Pemanfaatan limbah B3 berpedoman pada prinsip daur ulang, yaitu penggunaan kembali limbah B3 sebagai bahan baku pada proses selanjutnya dalam rangkaian proses produksi di industri, pemanfaatan sebagai bahan pengganti dalam suatu proses produksi komersial, atau perolehan kembali suatu kandungan yang masih bernilai dari limbah B3 melalui serangkaian proses pengolahan. Saat ini pemanfaatan limbah B3 sangat digalakkan, karena selain dapat menghilangkan sifat bahaya dari limbah B3, kegiatan ini dapat pula membantu menjaga kelestarian lingkungan melalui pengurangan penggunaan sumber daya alam.

Penimbunan Limbah B3

Penimbunan limbah B3 merupakan kegiatan menempatkan suatu limbah B3 pada suatu area yang didesain khusus untuk menimbun limbah B3. Kegiatan ini merupakan metode pembuangan limbah yang paling tua dan paling umum digunakan. Terdapat bermacam-macam metode untuk menimbun limbah B3, antara lain landfill, deep well injection, dam tailing hingga ditimbun di dasar laut. Semua limbah yang akan ditimbun harus dipastikan sudah inert dan tidak lagi memiliki sifat bahaya; jika masih memiliki sifat bahaya maka limbah tersebut harus diolah terlebih dahulu. Mengingat sifat bahaya dari limbah B3 yang akan ditimbun, maka lokasi penimbunan limbah B3 juga harus dipilih sedemikian rupa: stabil dari berbagai potensi bencana alam, bukan lahan subur untuk kegiatan bercocok tanam dan jauh dari keramaian/aktivitas manusia.

Pengangkutan Limbah B3

Pengangkutan limbah B3 adalah kegiatan pemindahan limbah B3 dari suatu lokasi pengelolaan ke lokasi pengelolaan lainnya. Semua kegiatan pengangkutan limbah B3 harus memiliki tujuan akhir pengelolaan dan tidak boleh dilakukan antar kegiatan yang memiliki fungsi yang sama. Kegiatan pengangkutan limbah B3 dapat disimulasikan sebagai berikut:

  • dari penghasil ke pengumpul
  • dari penghasil ke pemanfaat
  • dari penghasil ke pengolah
  • dari penghasil ke penimbun akhir
  • dari pengumpul ke pemanfaat
  • dari pengumpul ke pengolah
  • dari pengumpul ke penimbun akhir
  • dari pengolah ke pemanfaat
  • dari pengolah ke penimbun akhir
  • dari pemanfaat ke penimbun akhir

Jika pengangkutan dari penghasil berhenti di pengumpul, maka pengumpul tersebut akan bertindak sebagai penghasil baru ketika akan melakukan pengangkutan ke pemanfaat, pengolah atau penimbun.

Di antara semua kegiatan pengelolaan limbah B3, pengangkutan limbah B3 merupakan satu-satunya kegiatan yang izin operasionalnya tidak diberikan oleh KLHK, melainkan oleh Departemen Perhubungan. Peran KLHK dalam kegiatan pengangkutan limbah B3 adalah memberikan rekomendasi kepada perusahaan yang melakukan jasa pengangkutan limbah B3, yang tanpa rekomendasi ini izin operasional dari Departemen Perhubungan tidak akan diberikan.

Pada dasarnya kegiatan pengangkutan limbah B3 adalah kegiatan penyimpanan limbah B3 dalam bentuk berjalan. Oleh sebab itu, semua kaidah penyimpanan limbah B3 harus pula diterapkan dalam pengangkutan limbah B3, antara lain:

  • pemilihan alat angkut yang sesuai dengan limbah B3 yang akan diangkut
  • pelekatan simbol limbah B3 pada badan kendaraan pengangkut sebagai bentuk komunikasi bahaya atas limbah B3 yang diangkut
  • penerapan aturan segregasi dalam pemuatan limbah B3 ke dalam alat angkut
  • penerapan inspeksi kondisi limbah B3 yang diangkut oleh pengemudi

Berdasarkan PP 101/2014, jenis kendaraan yang digunakan untuk mengangkut limbah B3 harus disesuaikan dengan kategori limbah B3-nya. Untuk limbah B3 kategori 1 harus diangkut menggunkan kendaraan tertutup, sedangkan limbah B3 kategori 2 boleh diangkut menggunakan kendaraan terbuka.

Pengangkutan limbah B3 berkaitan dengan kegiatan bongkar-muat limbah. Dalam hal pemuatan, pengemudi harus memastikan bahwa limbah B3 yang akan diangkut dikemas dengan baik. Pengemudi memiliki hak penuh untuk tidak mengangkut limbah B3 yang kemasannya tidak baik/layak.

Beberapa hal yang perlu diperhatikan saat bongkar-muat limbah B3 antara lain:

  1. Pastikan hanya melakukan bongkar-muat di lokasi yang sudah ditentukan.
  2. Usahakan lokasi bongkar-muat dibuat tertutup (indoor), atau minimal memiliki atap.
  3. Buat saluran penampungan tumpahan yang kedap air dan bak penampungan tumpahan yang buntu di lokasi bongkar-muat.
  4. Tutup saluran penampungan limpasan air hujan saat kegiatan bongkar-muat berlangsung untuk menghindari masuknya tumpahan limbah B3 ke dalam saluran tersebut.
  5. Hindari melakukan kegiatan bongkar-muat saat hujan untuk menghindari potensi tumpahan yang akan larut dan terbawa oleh limpasan air hujan.
  6. Seluruh muatan harus diikat kuat selama dan posisinya diatur dengan baik sehingga bebannya terdistribusi secara merata di sumbu-sumbu kendaraan.
  7. Pastikan pemuatan kemasan ke dalam kendaraan juga memperhitungkan kemudahan dan keamanan saat pembongkaran.

Dokumen pengangkutan limbah B3

Seluruh kegiatan pengangkutan limbah B3 yang melewati fasilitas publik harus dilengkapi dengan dokumen pengangkutan limbah B3, atau yang biasa disebut sebagai limbah B3. Manifest limbah B3 dapat berupa lembaran kertas yang dicetak ataupun elektronik. Setiap perusahaan penyedia jasa pengangkutan limbah B3 harus memiliki manifest yang akan diperoleh pada saat pengjuan rekomendasi pengangkutan ke KLHK. Dokumen ini merupakan salah satu bentuk komunikasi bahaya dari suatu limbah B3 yang diangkut, yang di dalamnya berisi informasi yang mencakup:

  • nama, alamat dan nomor telepon penghasil limbah, termasuk lokasi pengambilannya
  • nama, alamat dan nomor telepon perusahaan pengangkut limbah
  • nama, alamat dan nomor telepon fasilitas penerima limbah
  • identitas, bentuk fisik, karakteristik, kode, jumlah, kelas bahaya dan kode pengangkutan, dan
  • informasi terkait tindakan yang harus dilakukan pada saat terjadi kedaruratan selama pengangkutan.

Sistem manifest ini juga diterapkan di negara lain yang sudah meratifikasi Konvensi Basel dan melakukan kegiatan pengelolaan limbah B3, namun implementasinya bisa berbeda satu sama lain tergantung regulasi setempat. Contohnya adalah di Amerika Serikat, di mana satu manifest dapat digunakan untuk empat jenis limbah yang kompatibel satu sama lain (seperti manifest pesawat), sementara di Indonesia satu manifest hanya dapat digunakan untuk satu limbah saja.

Beberapa hal penting tentang manifest limbah B3:

  1. Manifest limbah B3 terdiri dari tiga bagian yang masing-masing harus diisi sebagai berikut:
    • Bagian pertama (atas) oleh penghasil
    • Bagian kedua (tengah) oleh pengangkut
    • Bagian ketiga (bawah) oleh fasilitas penerima (pengumpul, pemanfaat, pengolah atau penimbun)
  2. Manifest limbah B3 merupakan dokumen pengangkutan limbah B3, bukan dokumen pengolahan/penimbunan limbah B3.
  3. Manifest limbah B3 merupakan dokumen negara sehingga harus dijaga jangan sampai hilang. Kehilangan manifest harus dilaporkan ke pihak kepolisian.
  4. Satu kendaraan pengangkutan dapat memuat lebih dari satu manifest, tetapi satu manifest tidak boleh dimuat di lebih dari satu kendaraan pengangkutan.
  5. Manifest limbah B3 yang saat ini berlaku mampu mengakomodir hingga tiga kali perpindahan moda transportasi. Pada pengangkutan dengan lebih dari tiga kali perpindahan moda transportasi harus melibatkan pengumpul berizin untuk dilakukan pergantian manifest.
  6. Masing-masing salinan manifest harus disimpan dan didistribusikan sesuai ketentuan.

 Kompetensi pengemudi angkutan limbah B3

Salah satu kendala terbesar pada sektor pengangkutan limbah B3 adalah kompetensi pengemudi angkutan limbah B3. Kompetensi yang dimaksud di sini bukanlah keahlian mengemudi, melainkan pengetahuan tentang limbah B3 yang diangkutnya termasuk bagaimana cara penanganannya dengan baik dan benar. Tanpa bermaksud mendiskreditkan profesi pengemudi, namun tak bisa kita pungkiri bahwa mayoritas pengemudi angkutan darat di Indonesia memiliki tingkat pendidikan yang kurang. Oleh sebab itu saat ini Departemen Perhubungan membuat sebuah aturan tentang kompetensi pengemudi angkutan limbah B3, di mana para pengemudi ini harus memiliki sertifikasi khusus yang dapat diperoleh melalui diklat. Hanya saja kurikulum untuk diklat ini masih belum ditetapkan. Diklat dan sertifikasi pengemudi angkutan limbah B3 ini juga sudah diterapkan di beberapa negara, khususnya negara maju, salah satunya ialah Australia. Kurikulum diklat dan sertifikasi pengemudi angkutan limbah B3 di Australia mencakup empat aspek sebagai berikut:

  1. Pengetahuan tentang limbah B3
  2. Pengetahuan tentang aspek K3L
  3. Pengetahuan tentang kendaraan
  4. Pengetahuan tentang komunikasi dan pelayanan pelanggan

Penyimpanan Limbah B3

Penyimpanan limbah B3 bertujuan untuk menyimpan sementara suatu limbah B3 sampai dilakukan pengelolaan lebih lanjut untuk mencegah terlepasnya limbah B3 tersebut ke lingkungan sehingga potensi bahaya terhadap manusia dan lingkungan dapat terhindarkan. Penyimpanan limbah B3 harus mematuhi aturan penyimpanan yang ditetapkan oleh Pemerintah. Secara umum jangka waktu penyimpanan limbah B3 adalah maksimal 90 hari terhitung sejak limbah tersebut dihasilkan. Jika limbah B3 tersebut dihasilkan dalam jumlah sedikit – di Indonesia adalah kurang dari 50 kg/hari – maka penyimpanan dapat dilakukan lebih dari 90 hari. Selain itu terdapat pula aturan terpisah untuk jangka waktu penyimpanan limbah infeksius yang dihasilkan dari fasilitas kesehatan yang tertuang dalam Kep-1204/MENKES/SK/X/2004 tentang Persyaratan Kesehatan Lingkungan Rumah Sakit. Dalam aturan ini disebutkan bahwa penyimpanan limbah infeksius pada musim kemarau maksimal adalah 1 x 24 jam, sedangkan pada musim hujan maksimal adalah 2 x 24 jam.

Seperti halnya pada kemasan, fasilitas penyimpanan limbah B3 juga harus ditandai dengan simbol limbah B3 sesuai dengan karakteristik limbah B3 yang disimpan di dalamnya.

Setiap kemasan limbah B3 yang disimpan harus dijaga agar selalu dalam kondisi yang baik selama penyimpanan: tidak penyok dan berkarat, tidak bocor, serta tidak menggembung. Jika salah satu kondisi tersebut terjadi pada kemasan, maka harus dilakukan pengemasan ulang dengan cara memindahkan muatannya ke dalam kemasan lain. Selalu berhati-hati dalam menangani dan menyimpan kemasan untuk menghindari terjadinya kerusakan dan kebocoran pada kemasan; gunakan alat bantu ketika akan mengangkat kemasan, jangan menggelindingkan kemasan apalagi dengan tangan kosong.

Penyimpanan limbah B3 juga harus dilakukan berdasarkan karakteristiknya; limbah-limbah dan/atau limbah dan bahan dengan karakteristik yang tidak saling cocok harus disimpan terpisah agar tidak bereaksi satu sama lain, dibatasi dengan sekat, tanggul, tembok rendah, atau penghalang lainnya.

Penyimpanan limbah B3 dengan kemasan berupa drum dapat pula dilakukan dengan cara dibuat bertumpuk untuk memaksimalkan penggunaan area penyimpanan. Namun demikian hal ini tidak boleh diterapkan untuk limbah yang bersifat mudah meledak, mudah menyala, dan reaktif. Limbah-limbah jenis ini harus disimpan di area khusus untuk mengurangi risiko publik untuk berkontak dengan limbah-limbah tersebut atau terpapar ledakan, sekaligus mencegah migrasi ke lingkungan jika terjadi tumpahan. Limbah-limbah dengan karakteristik mudah meledak, mudah menyala, dan reaktif harus dijauhkan dari kondisi berikut:

  1. api,
  2. permukaan panas, seperti mesin,
  3. pancaran panas atau sinar matahari,
  4. kegiatan pemotongan dan pengelasan logam,
  5. friksi panas – jangan menyeret kemasan di sepanjang lantai,
  6. percikan dari listrik statis, kegiatan elektrik, atau friksi, dan
  7. untuk limbah reaktif harus dijauhkan dari air.

INSPEKSI PENYIMPANAN LIMBAH B3

Inspeksi area penyimpanan limbah B3 harus dilakukan secara rutin seminggu sekali. Inspeksi ini dapat melindungi kita dari potensi tumpahan dan bahaya lainnya sebelum terjadi. Daftar periksa harus dibuat guna mempermudah inspeksi – daftar periksa ini harus rinci serta mencakup prosedur penandaan  dan pengelolaan penyimpanan. Daftar periksa sekurang-kurangnya harus mencakup:

  1. ada/tidaknya kebocoran atau ceceran dari kemasan ,
  2. kondisi kemasan, termasuk penyok, gembung, dan karat,
  3. simbol dan label – periksa apakah ada simbol dan/atau label yang terlepas dan tanggal pengemasan yang tertulis untuk mencegah penyimpanan melebihi 90 hari, dan
  4. pengelolaan penyimpanan, seperti jarak antar baris dan ketinggian tumpukan.

Beberapa tips praktis dalam melakukan inspeksi antara lain adalah sebagai berikut:

  1. Ikuti daftar periksa – buat suatu catatan rinci jika terdapat sesuatu yang tidak sesuai.
  2. Lakukan dengan seksama. Periksa kondisi kemasan apakah terdapat tumpahan/ceceran dan perkaratan.
  3. Periksa sekeliling kemasan dan seluruh area penyimpanan.
  4. Periksa apakah ada noda/kotoran pada bak penampungan.
  5. Catat segala sesuatu yang tidak biasa pada bak penampungan – bahkan sekalipun mungkin hal tersebut bukan suatu masalah.
  6. Segera lakukan tindakan penanggulangan jika terjadi masalah.
  7. Pelihara buku catatan inspeksi.

 

Pengemasan Limbah B3

Setelah melakukan karakterisasi dan kita mengetahui apakah antara limbah satu dengan lainnya saling tidak cocok atau saling bereaksi maka kita dapat menentukan jenis kemasan yang sesuai.  Tujuan dari pengemasan limbah B3 adalah untuk mencegah kontak antara limbah tersebut dengan manusia dan lingkungan sekitar. Kemasan limbah B3 harus memiliki penutup yang kuat dan mampu mengungkung limbah yang dikemasnya sebelum ditangani lebih lanjut. Kemasan limbah B3 juga harus selalu dalam kondisi tertutup jika sedang tidak dilakukan penambahan muatan, pengambilan sampel atau pemindahan muatan.

Jenis-jenis kemasan yang dapat digunakan untuk mengemas limbah B3 antara lain drum plastik tutup lebar, drum plastik tutup kecil, drum logam tutup lebar, drum logam tutup kecil, jumbo bag, jerry can, IBC box dan sebagainya.

Ada beberapa hal yang perlu diperhatikan dalam pemilihan kemasan limbah B3, yaitu:

  1. Jumlah limbah yang akan dikemas. Jika limbah yang akan dikemas hanya berjumlah kecil/sedikit maka gunakanlah kemasan kecil. Sebagai contoh jika limbah yang akan dikemas hanya berjumlah 5 liter maka lebih baik dikemas menggunakan jirigen, bukan drum berukuran 200 liter.
  2. Pastikan limbah yang akan dikemas tidak akan bereaksi dan merusak kemasan. Pilihlah kemasan yang terbuat dari bahan inert terhadap limbah yang dikemas. Misalnya untuk mengemas limbah yang bersifat korosif harus menggunakan kemasan yang terbuat dari plastik, bukan logam.
  3. Bentuk fisik limbah yang akan dikemas. Sebagai contoh jika akan mengemas limbah cair menggunakan drum maka gunakan drum yang memiliki penutup kecil atau yang biasa diistilahkan sebagai closed top drum. Sebaliknya jika akan mengemas limbah padat menggunakan drum maka gunakan drum yang memiliki penutup lebar, atau yang biasa diistilahkan sebagai open top drum.
  4. Jika kemasan yang akan digunakan adalah kemasan bekas mengemas limbah atau bahan lain, pastikan limbah atau bahan yang sebelumnya dikemas cocok dengan limbah B3 yang akan dikemas kemudian. Disarankan untuk mencuci terlebih dahulu kemasan bekas yang akan digunakan untuk mengemas limbah B3.

Beberapa tips praktis untuk pengemasan limbah B3 adalah sebagai berikut:

  1. Pastikan Anda mengetahui limbah-limbah mana yang tidak saling cocok; jauhkan satu sama lain dan kemas dalam kemasan terpisah.
  2. Pastikan kemasan tidak rusak oleh limbah B3 yang dikemasnya.
  3. Jika Anda melakukan pencucian kemasan, pastikan untuk menampung dan melakukan karakterisasi air cuciannya sebelum dibuang.
  4. Jika suatu kemasan akan digunakan kembali secara rutin, pertimbangkan untuk menetapkan limbah yang akan dikemas ke dalamnya. Hal ini akan mempermudah Anda menggunakan kembali kemasan tersebut tanpa perlu mencucinya terlebih dahulu.
  5. Gunakan corong untuk menuangkan limbah cair ke dalam kemasan guna menghindari tumpahan. Jangan menggunakan satu corong yang sama untuk semua jenis limbah B3.
  6. Beberapa limbah B3 dapat mengalami ekspansi volume karena fluktuasi suhu dan tekanan (misalnya solvent). Pastikan untuk tidak mengisi limbah B3 hingga penuh ke dalam kemasan, kecuali jika menggunakan iso tank.

Selain jenis-jenis kemasan yang telah disebutkan di atas, terdapat pula kemasan khusus untuk mengemas limbah infeksius, di mana kemasan ini memiliki simbol biohazard yang sudah tercetak langsung di badannya. Kemasan ini memiliki warna yang mencolok, antara lain kuning, merah dan jingga. Terdapat dua jenis kemasan untuk mengemas limbah infeksius sebagai berikut:

  1. Untuk limbah infeksius tajam dan dapat menyayat kulit (mis: jarum suntik dan scalpel), limbah jaringan/potongan organ tubuh, darah dan media agar bekas inokulasi bakteri harus dikemas dengan wadah yang keras, kedap air dan anti tusuk seperti ember/bin.
  2. Untuk limbah infeksius non tajam seperti perban, kasa dan kapas dapat dikemas menggunakan kantong plastik.

Batas maksimal pengisian limbah infeksius ke dalam kemasan, baik yang berupa wadah ember/bin maupun kantong plastik, adalah 3/4 penuh.

Hal-hal yang perlu diperhatikan dalam pengemasan limbah infeksius menggunakan kantong plastik biohazard adalah sebagai berikut:

  1. Pastikan hanya limbah infeksius non-tajam yang dikemas dalam kantong biohazard.
  2. Jangan mengisi lebih dari ¾ penuh.
  3. Setelah ¾ penuh, tarik perlahan untuk meminimalkan udara di dalam kantong – jangan mendorong kantong ke bawah atau melubanginya untuk mengeluarkan udara.
  4. Putar ujung atas kantong membentuk kepangan tunggal.
  5. Bentuk ikatan tunggal dari kepangan tunggal – jangan mengikat dengan model “telinga kelinci.
  6. Masukkan kantong biohazard ke dalam troli penyimpanan.

PENANDAAN KEMASAN LIMBAH B3

Semua kemasan limbah B3 yang telah terisi harus ditandai dengan simbol dan label limbah B3. Simbol dan label limbah B3 merupakan bentuk komunikasi bahaya dari suatu limbah B3. Simbol limbah B3 adalah gambar yang mewakili karakteristik suatu limbah B3, sedangkan label limbah B3 adalah tulisan yang berisi segala keterangan tentang suatu limbah B3 yang terdapat di dalam suatu kemasan. Adanya simbol dan label ini dapat memudahkan identifikasi suatu limbah B3 tanpa harus mengambil contoh limbah tersebut dan mengujinya di laboratorium, sekaligus memberikan peringatan kepada siapa saja yang akan menangani limbah B3 tersebut tentang potensi bahayanya.

Secara internasional, simbol limbah B3 sama saja dengan simbol B3, namun demikian Pemerintah Indonesia menetapkan simbol khusus untuk limbah B3 di Indonesia seperti yang diatur dalam PermenLH 14/2013, dan sebelumnya pada Kep-05/BAPEDAL/09/1995. Sepertinya hal ini dilakukan oleh Pemerintah untuk mencegah impor limbah B3 sebagaimana dilarang dalam UU 32/2009, karena jika simbolnya sama maka akan sulit untuk membedakan atau menentukan apakah yang diimpor tersebut adalah B3 atau limbah B3.

Hal-hal yang perlu diperhatikan dalam pelekatan simbol dan label limbah B3 antara lain adalah sebagai berikut:

  1. Pastikan kru yang bertugas memahami dengan baik arti dari simbol dan label yang dilekatkan pada kemasan.
  2. Pastikan simbol dan label yang digunakan ialah simbol dan label limbah B3, bukan simbol dan label B3
  3. Jika kemasan yang digunakan adalah kemasan bekas, pastikan simbol dan label sebelumnya sudah dilepas.

Characterization of X-Ray Films to be Stipulated as Hazardous Waste *)

Since generated from an activity, X-ray films at some point can end up as waste. Due to the use of fixer and developer solutions which contain silver halides on the printing process, X-ray films might also contain significant level of silver. Fixer and developer solutions themselves are classified as hazardous waste according to PP 101/2014, thus X-ray films might also be classified as hazardous waste as well. Since not listed as hazardous waste on PP 101/2014, characterization must be conducted in order to stipulate whether the X-ray films are classified as hazardous waste or not. Characterization conducted on this investigation was using two sheets of X-ray films which were taken in 1998 and 2004 respectively. From this characterization, it was obtained that X-ray films contains 1812 ppm of silver and 0,4148 ppm of mercury, and only leached out 1,214 ppm of silver. Within these results, X-ray films can be classified as hazardous waste category 2 according to PP 101/2014, with code B101d, and can be disposed directly into Secure Landfill Class 1, 2 or 3. As alternative, they can also be treated via recycling process to recover the silver. However, it is still suspected that the silver concentration, both on waste and TCLP, might be greater than the results obtained from this investigation if using X-ray films that are relatively new (0 – 5 years); further investigation should be conducted.

Keywords: X-ray films, hazardous waste, characterization, disposal.

*) Principal investigator: Muhammad Yusuf Firdaus, Senior Technical Engineer, PT Prasadha Pamunah Limbah Industri

Effect of the Use of Super Absorbent Polymer (SAP) and Its Order of Addition as Reagent on Hazardous Waste Solidification *)

Solidification is the most common technique used on the treatment of hazardous waste. The aim of this process is to alter the physical form of the waste which cannot be disposed directly to the landfills, with the incorporation of reagents. Portland cement is the most common reagent used in combination with sand or any other inert materials as filler. The common problem on this process is the relatively high water content which prevents the curing process, thus leads to the use of more reagent which increases the operational cost. Sorbent materials can be used to anticipate this problem, one of those is super absorbent polymer (SAP) which has been used on numbers of hazardous waste management cases in the U.S. From the trial, it was found that solidification process using SAP ratios of 0,1 (w/w) and adding it on the first stage, followed by Portland cement and sand ratios of 0,4 and 0,6 (w/w) respectively on the second stage, was able to obtain the minimum bearing strength criteria within the fastest the curing time.

Keywords: hazardous waste treatment, solidification, bearing strength, SAP.

*) Principal Investigator: Muhammad Yusuf Firdaus, Senior Technical Engineer, PT Prasadha Pamunah Limbah Industri