Teknik Solidifikasi/Stabilisasi
Stabilisasi • Stabilisasi adalah proses penambahan bahan aditif yang bertujuan untuk mengurangi sifat beracun limbah, dengan cara mengubah limbah dan komponen berbahayanya y y ke bentuk yyang dapat g p mengurangi g g laju j migrasi kontaminan ke lingkungan, atau mengurangi sifat beracun limbah. • Dalam proses stabilisasi ditambahkan bahan2 yang Dalam proses stabilisasi ditambahkan bahan2 yang memiliki sifat: – memperbaiki karakteristik fisik limbah dan mempermudah penanganannya; – mengurangi luas permukaan limbah; – mengurangi kelarutan polutan yang terkandung dalam limbah; – mengurangi sifat beracun kontaminan
Solidifikasi • solidifikasi adalah p proses ditambahkannya y bahan yang dapat memadatkan limbah agar terbentuk massa limbah yang padat. Bahan yang ditambahkan merupakan bahan yang dapat yang dapat : – menaikkan kekuatan fisik limbah – mengurangi kompresibilitas limbah – mengurangi permeabilitas limbah – solidifikasi dapat memperbaiki kekuatan dan kompresibilitas limbah, sehingga limbah, sehingga mengurangi laju penyebaran kontaminan ke lingkungan, serta meningkatkan kestabilan limbah agar tidak mengganggu lingkungan. lingkungan.
Tujuan S/S • mengkonversi limbah beracun menjadi massa yang: – inert, inert – memiliki daya leaching rendah, – kekuatan mekanik yang cukup yang cukup agar aman agar aman untuk di buang ke landfill limbah B3.
Karakteristik Produk S/S • stabil; • mampu menahan beban; • toleran l terhadap h d kondisi k di i basah b h dan d kering k i yang silih berganti; • permeabilitas rendah; • tidak menghasilkan g lindi yyang berkualitas g buruk
Kriteria bahan aditif • dapat memperbaiki karakteristik fisik limbah; • mengurangi luas permukaan limbah; • mengurangii kelarutan k l polutan l yang terdapat d dalam limbah; • mengurangi toksisitas kontaminan.
Jenis aditif • bahan pencampur: gipsum, pasir, lempung, pencampur: gipsum pasir lempung abu terbang; • bahan perekat/pengikat: semen, kapur, tanah perekat/pengikat: semen kapur tanah liat, dl;
Prosedur S/S • limbah B3 harus ditentukan karakteristiknya terlebih dahulu guna menentukan komposisi bahan‐bahan yang perlu ditambahkan; • setelah S/S diaplikasikan, dilakukan uji TCLP terhadap hasil olahan tersebut untuk mengukur konsentrasi parameter dalam lindi (extract/eluate). Hasil uji TCLP sebagaimana dimaksud, kadarnya tidak boleh melewati nilai baku mutu; • hasil stabilisasi selanjutnya diuji kuat tekan (compressive strength); nilai tekanan minimum sebesar 10 ton/m2, dan dan lolos uji paint filter test. • hasil stabilisasi yang memenuhi persyaratan baku mutu TCLP, nilai uji kuat tekan dan paint filter test harus ditimbun di tempat penimbunan (landfill) B3
Teknik S/S dilakukan S/S dilakukan untuk: • stabilisasi limbah cair B3 sebelum B3 sebelum dibuang ke landfill; • remediasi lahan‐lahan yang terkontaminasi remediasi lahan lahan yang terkontaminasi limbah B3.
Classification of S/S technology Classification of S/S technology 1.. cchemical processes: e ca p ocesses: 1. cement‐based process, 2. pozzolan‐based processes, 3. lime‐based processes
2. physical processes: 1. macroencapsulation/containerization 2. non‐chemical microencapsulation; 3 thermal processes: 3. th l 1. 2.
thermoplastic polymer encapsulation vitrification.
Cement • Composition: Co pos t o : – – – –
67% CaO (C), 22% SiO2 (S), 5% Al2O3 (A), 3% Fe2O3 (F), and 3% other components.
• It normally contains four major phases: – – – –
alite (50–70% Ca3SiO5 or “C3S”), b lit (15–30% Ca2SiO4 or “C2S”), belite (15 30% C 2SiO4 “C2S”) aluminite (5–10% Ca3Al2O6 or “C3A”), and ferrite (5–15% Ca4Al2Fe2O10 or “C4AF”) ferrite (5–15% Ca4Al2Fe2O10 or C4AF )
RAW MATERIALS of CEMENT The fundamental chemical compounds to produce cement clinker are: Lime (CaO) Silica ((SiO2) Alumina (Al2O3) Iron Oxide (Fe2O3) Raw materials off clinker R t i l used d in i the th production d ti li k cementt
Fly y ash: by-product yp of burning g finely yg grounded coal either for industrial application pp or in the production of electricity (Macfadyen, 2006) (Hoffman, 2006)
S/S technology using cement S/S technology using cement 1 Chemical 1. Chemical fixation of contaminants by fixation of contaminants by interactions between the hydration products of cement and the contaminants of cement and the contaminants, 2. Physical adsorption of contaminants on the surface of cement hydration products or surface of cement hydration products, or 3. Physical encapsulation of contaminated waste or soil. il
Schemes of S/S processing with cement • In‐drum processing — The S/S binders are added to the waste contained in a drum or other container. The waste‐binder matrix is t i di d th t i Th t bi d ti i normally disposed of in the drum after mixing and setting. • In‐plant processing — A plant and/or process is specifically designed for solidifying and stabilizing bulk waste materials The designed for solidifying and stabilizing bulk waste materials. The process may be used to manage wastes from an internal industrial operation, or a plant may be specifically built and operated to solidify and stabilize wastes from external sources. • Mobile plant (ex situ) processing — In this scheme, the processing equipment, which is either mobile or can be easily transported, is set up site to site. • In‐situ processing — In situ processing Binders or solidifying/stabilizing materials are Binders or solidifying/stabilizing materials are injected directly to a lagoon or soil subsurface to promote the solidification/stabilization of the contaminated sludge or soil.
In‐drum In drum processing processing • Toxic and hazardous liquids and sludges are often disposed on‐site i d in drums. • In‐drum S/S methods aim to utilize these existing drums as both a mixing vessel and storage container for hazardous waste. • Typical in‐drum mixing processes involve the following steps: Typical in drum mixing processes involve the following steps: – Evaluation/identification of contents in each drum – Evaluation of drum condition and head space – Preparation of materials handling location, including concrete pad or Preparation of materials handling location including concrete pad or gravel surface, chemical storage, and mixing equipment – Addition and mixing of S/S chemicals using mixers or propeller s – Placement of drums in a secure area for curing – Addition of inert material to any remaining head space and replacement of top to each drum – Final disposal of drums
In‐situ In situ treatment treatment • The procedure for an in‐situ treatment process e p ocedu e o a s tu t eat e t p ocess may utilizes the existing lagoon as a mixing area. p yp • The follow steps are typical for stabilization/solidification of waste in‐situ: – Addition of reagent, such as kiln dust or flyash, using mechanical or pneumatic application. h i l ti li ti – Mixing with backhoe or excavator until stabilization/begins. / g – Setting/gelling for 24‐48 hours. – Off‐gas treatment to collect hazardous vapors
In‐situ In situ S/S S/S
In‐situ S/S / mixing, with with single auger.
Mobile mixing, ex‐situ Mobile mixing, ex situ • • •
Wastes are physically removed from their location using pumping or construction equipment mechanically mixed with reagents and deposited into a prepared equipment, mechanically mixed with reagents, and deposited into a prepared disposal site. This method is best suited for liquids and highly liquid sludges that can be pumped. Special equipment may be used to employ the mobile mixing method on high solids content sludges and soils. high solids content sludges and soils Mobile mixing plant S/S typically requires the following project sequencing: – – – – – – – – – –
Excavation to remove contaminated waste Classification of wastes Mobile plant setup and mixing Mobile plant setup and mixing Preparation of remedial site for installation of mobile system, including necessary utilities/electricity Preparation of final disposal site Installation of raw and treated waste handling systems, including pumps or construction equipment Screening of wastes to remove particles too large for treatment (typically 2 inches or greater in diameter) Mixing of binding agents, water, and waste Off‐gas treatment to collect hazardous vapors g p Final Disposal
Area mixing, ex‐situ Area mixing, ex situ • Waste Waste is placed in a layer over the disposal is placed in a layer over the disposal area in 2"‐24" thicknesses and is then overlaid with a layer of reagents with a layer of reagents. • The two layers are then lifted and turned with a mechanized vehicle similar to tilling a mechanized vehicle, similar to tilling. • The mixture is air dried or compacted. • Additional waste/reagent layers may be added up to the determined final material height.
Area mixing Area mixing Area mixing provides an economical method for S/S of waste liquids and sludges without the use of conventional, stationary mixing equipment. without the use of conventional stationary mixing equipment The steps are: 1. Selection/preparation of treatment area 2 2. Excavation and transport of waste Excavation and transport of waste 3. Spreading of waste in desired thickness over disposal area using construction equipment 4. Spreading of required amounts of reagents over waste 5. Mixing of materials using high‐speed rotary mixer 6. Compaction of mixed layer 7. Repeat steps 2‐7 until allowable solidified waste height has been attained 8. The final layer is covered with earth and seeded as a final cap., or the waste may be removed to another disposal site.
Ex‐situ Ex situ area mixing area mixing
Polymer S/S technology Polymer S/S technology • • •
USEPA : "polymer S/S technologies process waste at relatively low temperature by combining or surrounding wastes with liquid polymers Cooling or curing of the combining or surrounding wastes with liquid polymers. Cooling or curing of the polymer then produces a solidified final waste form product". Polymer S/S can be applied for either microencapsulation or macroencapsulation; also can be accomplished ex situ or in situ. USEPA divided polymers into two categories: USEPA divided polymers into two categories: – Thermoplastic . Thermoplastic binders can be melt to a flowable state when heated and harden to a solid when cooled – Thermosetting. Thermosetting binders require the combination of several ingredients to polymerize and harden (irreversible)
• • •
When the waste particles are small solid particles (< 60 mm) and homogeneously distributed, the organic polymer matrix is known as microencapsulation. In microencapsulation, individual waste particles are fully surrounded and encapsulated by the polymer matrix. When the waste particles are large (> 60 mm), clean polymer can be placed around the waste and this process is usually called macroencapsulation. USEPA has identified macroencapsulation as the best demonstrated available technology (BDAT)
Polymer S/S technology Polymer S/S technology • Both thermoplastic polymers and organic polymers are hydrophobic after curing and thus resist leaching. • This property makes polymers ideal for trapping highly toxic metals and organic compounds. toxic metals and organic compounds. • Organic polymer microencapsulation, specifically, is a useful method to encapsulate waste because it is well‐ suited for many types of applications including liquid suited for many types of applications, including liquid waste solidification; it exhibits a high degree of impermeability, and can quickly attain physical strength. strength • Polymer materials: urea formaldehyde, polyester resin PETE
Vitrification • • • •
•
Dilakukan pencairan dan peleburan bahan pada suhu > 1600oC, yang diikuti dengan g p pendinginan g cepat, sehingga p , gg terbentuk p padatan amorf, non kristalin. , Digunakan pada lahan yang terkontaminasi, baik in situ maupun in plant. Dengan vitrifikasi, struktur limbah menjadi lebih stabil dan berkurang laju migrasinya ke lingkungan sekitar. Vitrifikasi in situ: in situ: Arus listrik dialirkan ke dalam tanah, hingga tanah, hingga menimbulkan panas. panas. Akibatnya tanah akan mencair, menjadi massa lelehan yang bersifat lebih konduktif dan menjadi medium transfer panas yang terus mengembang. Proses vitrifikasi diawali dengan memasang lapisan grafit dan gelas pada permukaan tanah, dengan elektroda yang diletakkan pada keempat siisi yang lebarnya 8 m dengan kedalaman yang dikehendaki. Selanjutnya dilakukan pemanasan dengan aliran listrik, yang mengakibatkan terjadinya pelelehan tanah yang terkontaminasi, yang kemudian membentuk gelas amorf. Tanah meleleh dengan laju 3‐6 ton/jam, dengan kecepatan leleh 2.5‐5 cm/jam. P d saatt suhu Pada h naik, bahan ik b h organik ik menguap dan d terurai t i secara anaerobik bik menjadi unsur‐unsurnya. Gas‐gas tersebut bergerak perlahan menuju permukaan tanah yang mencair. Di permukaan tanah gas‐gas tersebut akan terbakar dengan bantuan oksigen. Sedangkan polutan yang tidak menguap akan terikat di dalam tanah yang telah yang telah berubah menjadi gelas
Kapsulasi makro • Limbah ba B3 dibungkus 3 d bu g us da dalam a kapsul apsu pe pembungkus bu g us yang bersifat inert dan kedap air. Bahan pembungkus dapat berupa campuran fiberglass, resin epoksida, dan k d d resin polyurethane. l h Campuran tersebut disemprotkan pada dinding kontainer limbah, sehingga limbah sehingga terbentuk jaket yang yang melindungi limbah tersebut dari pelindian dan tekanan‐tekanan mekanik. Semen kadang‐kadang g g digunakan pula untuk membentuk kapsul makro pada limbah laboratorium.
Skema vitrifikasi penurunan muka tanah grafit dan gelas
tanah terkontaminasi
penimbunan tanah penutup
elektroda
tanah yang memadat
Skema vitrifikasi
Compatibility of Selected Waste Categories with Diff Different S/S Techniques t S/S T h i Waste Component ORGANICS
Cement-Based Cement Based
Treatment Type Thermoplastic Pozzolan-Based Pozzolan Based Mi Microencapsulation l i
Surface E Encapsulation l i
Must first be May impede Organics may Organic solvents May impede setting, may escape vaporize on heating absorbed on solid and oils may escape as vapor setting, p matrix as vapor Solid organics Good-often increases Possible use as Compatible-many Good-often (e.g., plastics, binding agent in encapsulation durability increases durability resins, tars) this system materials are plastic INORGANICS C bbe neutralized Can t li d Can be neutralized Cement will neutralize Compatible, will Acid wastes before acids neutralize acids before incorporation incorporation Sulfates Halides y metals Heavy Radioactive materials
May retard setting and cause spalling unless special cement is used Easily leached from cement, may retard setting Compatible p Compatible
Compatible May retard set, most are easily leached Compatible p Compatible
May dehydrate and rehydrate causing splitting
May dehydrate and rehydrate Compatible p Compatible
Compatible Compatible Compatible p Compatible
Contoh aplikasi remediasi tanah dg S/S Tempat Kontaminan Midwest US Cu, Cr. Ni Plating Company Alaska Minyak refinery Vinil klorida dan etilena Kentucky diklorida Northeast Lumpur minyak, Pb, Cr, As Refinery
Semen portland dan bahan aditif khusus Semen portland dan bahan aditif khusus Abu terbang dengan kadar CaO tinggi
>50, bervariasi >25%, bervariasi
Velsicol Chemical
Semen portland, abu dan bahan aditif khusus
5-15%, bervariasi
Pestisida dan resin, 45% komponen organik
Amoco Minyak y dan sampah p Wood River mengandung Cd, Cr, Pb Vickery, Ohio
Bahan pengikat Semen portland
Bahan aditif khusus
Limbah asam, 500 ppm PCB, Kapur dan abu terbang dioksin
Metaplating, 9500 ppm Al, 750 ppm Ni, 220 Kapur Wisconsin ppm Cr, 2000 ppm Cu
% 20
15-30%
15% CaO + 5% fly ash 10-25
Uji TCLP (T i i Ch (Toxicity Characteristic Leaching Procedure) i i L hi P d ) • Uji TCLP adalah TCLP adalah metoda analisis guna menentukan mobilitas kontaminan organik atau anorganik yang ada dalam limbah B3 • Prosedur mengikuti metoda US EPA 1311 : – Limbah dihancurkan dan diayak dengan saringan 9.5 mm. – Hasil ayakan dicampur dengan larutan asam asetat pH 2.88 + 0.05 pada 0 05 pada rasio berat larutan : padatan : padatan 20:1. 20:1 – Campuran diagitasi selama 18 jam pada 30 rpm, suhu 22oC, kemudian disaring dengan filter fiber glass berukuran 0.6‐0.8 um – Kandungan kontaminan pada filtrat diuji dengan metoda yang sesuai yang sesuai 32
Uji TCLP (lanjutan) TCLP (lanjutan) • Pengujian limbah dengan kadar bahan organik yang mudah menguap dilakukan dengan prosedur khusus, dengan wadah berbentuk silinder yang diisi penuh dan tertutup rapat selama proses agitasi. • Hasil pengujian kadar kontaminan dibandingkan dengan baku mutu uji TCLP guna menentukan sifat b b h / d k berbahaya/tidaknya l b h yang diuji. limbah d ( h (Lihat Lampiran III PP No. 101/2014) 33
Metoda analisis limbah B3 pada ekstrak k k Uji TCLP • Total Total logam logam berat: Spektrofotometri berat: Spektrofotometri Serapan Atom (AAS) • Nitrat‐nitrit: spektrofotometri Nitrat nitrit: spektrofotometri • Sianida: spektrofotometri • Komponen organik (organoklorin, keton, alkana): gas kromatografi
34
Botol ekstraksi untuk uji TCLP RA-119 Borosilicate Glass Bottle B l ini Botol i i untukk limbah li b h organik ik dan d anorganik mudah menguap, bermulut lebar (100 mm), tebal, bebas logam berat, bertutup dengan lapisan teflon.
RA-202 Plastic Extraction Bottle Botol polyethylene bermulut lebar (100mm), untuk ekstraksi pd uji TCLP l 35
Contoh agitator untuk ekstraksi pada uji TCLP
DC‐20S 4‐Place Agitator with plastic DC 20S 4 Pl A i ih l i bottles for inorganics extraction
36
Paint filter test Paint filter test • Uji ini mengukur ada/tidaknya cairan bebas yang terkandung pada limbah B3 yang diuji. • Dapat dilakukan terhadap limbah B3 yang B3 yang belum diolah, ataupun yang telah distabilisasi. • Limbah ditempatkan pada saringan cat baku. cat baku. Apabila dalam 5 menit ada cairan yang lolos, limbah B3 dinyatakan mengandung cairan, dan diharuskan diolah terlebih dahulu sebelum dibuang ke landfill.
