Speciation and environmental risk of heavy metals in biochars produced by pyrolysis of chicken manure and water-washed swine manure

This study was conducted to investigate the speciation, bioavailability and environmental risk of heavy metals (HMs) in chicken manure (CM) and water-washed swine manure (WSM) and their biochars produced at different pyrolysis temperatures (200 to 800 °C). As the pyrolysis temperature increased, the remaining proportion, toxicity characteristic leaching procedure (TCLP), HCl and diethylenetriamine pentaacetic acid (DTPA) of HMs gradually declined. This result proved that the speciation of HMs in chicken manure biochars (CMB) and water-washed swine manure biochars (WSMB) was influenced by pyrolysis temperature. The proportions of stable fractions were enhanced with increased pyrolysis temperature and weakened the HM validity for vegetation at 800 °C. Finally, the results of the risk assessment showed that the environmental risk of HMs in CMB and WSMB decreased with increasing pyrolysis temperature. Therefore, pyrolysis at 800 °C can provide a practical approach to lessen the initial and underlying heavy metal toxicity of CMB and WSMB to the environment.

A Comparison in Metal Leachability Between Phosphoric Acid and Ascorbic Acid Stabilised Ferrochrome Slag

Ferrochrome (FeCr) slag was milled and stabilised with either ascorbic acid or phosphoric acid. The stabilised FeCr was then geopolymerised with 1 M KOH in order to obtain a monolith with at least an unconfined compressive strength of 1 MPa. The leachability of metals of the stabilised geopolymerised monoliths were then compared with the unstabilised geopolymerised monolith. Ascorbic acid stabilisation was only effective in Cr leaching reduction by 99.45% but was not effective on immobilisation of Fe, Zn, Ni and Mn. Ascorbic acid stabilisation was thought to proceed via the reduction of Cr(VI) species to insoluble Cr (III) species. Phosphate stabilisation reduced the leachability of Cr, Ni, Zn, Mn, Fe by 99.5%, 67.1%, 71.1%, 96.8% and 85.4% respectively. Phosphate stabilisation was thought to proceed via the formation of phosphate compounds of the metal ions in question. The phosphate stabilised FeCr slag leachability was within the allowable Toxicity Characteristic Leaching Procedure (TCLP) limits and its use is not detrimental to the environment.

POTENSI LIMBAH B3 SPENT BLACHING EARTH SEBAGAI BAHAN BAKAR PADA INDUSTRI MINYAK GORENG PT. ABC

SBE (spent bleaching earth) sebagai hasil samping dari pemakaian bleaching earth pada proses fraksinasi produksi minyak dan proses produksi SCD (semi continous deodorizer) sebagai residu sisa filtrasi. Kondisi eksisting pada industri X, sekitar 8.196,890ton/tahun LB3 SBE belum dimanfaatkan dan belum diolah yang dilakukan secara mandiri. Penelitian ini bertujuan untuk mendapatkan potensi dari LB3 SBE sebagai campuran bahan bakar pada PT. ABC. Metode yang digunakan adalah dengan uji kualitas batu bara (bahan bakar eksisting) dan uji kulitas pada LB3 SBE dengan parameter logam berat, kadar air dan nilai kalor. Dari hasil penelitian didapatkan kualitas batu bara yang digunakan cukup bagus karena memiliki kandungan sulfur, volatile dan fix carbon yang rendah. Emisi cerobong masih memenuhi baku mutu sesuai Permen LH No. 07 Tahun 2007. Sedangkan pada TCLP (Toxicity Characteristic Leaching Procedure), didapatkan SBE masuk kategori 1 (bersifat berbahaya) sebagai LB3 karena nilai TCLP yang lebih banyak pada kategori A. Dari uji nilai kalor dan kadar air, SBE sangat berpotensi untuk dimanfaatkan sebagai bahan bakar karena memenuhi syarat minimal sebagai bahan bakar (11 MJ/kg atau setara dengan 2.627,305 Kkal/kg dan 2,5%). Potensi LB3 SBE untuk dimanfaatkan sebagai bahan bakar sangat tinggi, baik dari segi kuantitas maupun kualitas dihasilkan pada industri pengolahan kelapa sawit.

Imobilização de metais pesados presentes nos resíduos de quartzito por meio da incorporação em argamassas com substituição total do agregado natural

RESUMO Este trabalho objetivou imobilizar metais pesados presentes nos resíduos de quartzito por meio da incorporação em argamassas em substituição total ao agregado natural. Dois tipos de resíduos foram utilizados: os resíduos de fragmentação das aparas (QS) e os do pó de serragem (QP). Os resíduos foram caracterizados por fluorescência de raios X, difração de raios X e ensaios de toxidade conforme metodologia da Norma Brasileira (NBR) 10005, da NBR 10006 e do Toxicity Characteristic Leaching Procedure (TCLP) 1311. Então, foram analisadas composições de argamassas contendo cimento, cal e os resíduos (QS, QP) utilizando-se a técnica de delineamento de mistura, determinando os melhores traços, o melhor tipo de cura (imersa ou úmida) e, posteriormente, avaliando a resistência dos corpos de prova após cura. A caracterização do resíduo de quartzito revelou a presença de vários metais pesados e extratos lixiviados em contato com a água, classificando-o como resíduo de Classe I — Perigoso. Os resultados indicam que as composições determinadas foram capazes de imobilizar os metais pesados presentes nos resíduos de quartzitos, bem como resultou em argamassas com resistências mecânicas superiores a 2 MPa. Por fim, mostrou-se que essa técnica de solubilização e estabilização dos contaminantes presentes nos resíduos de quartzito é uma alternativa tecnologicamente viável e ambientalmente adequada para a destinação final desses resíduos.

A comparison of waste leaching determination methods in the context of dewatered oil sands fine tailings

Leaching tests are an important component in assessing the potential of contaminants to leach from waste materials to the environment. Numerous leaching test protocols have been developed for different applications. In this study, we compare four different methods in the context of assessing leaching of inorganic ions from oil sands tailings. The four methods compared were: United States Environmental Protection Agency (EPA) Toxicity Characteristic Leaching Procedure; ASTM D6234; ASTM D3987; and what we refer to as the Deionized method (modified from Syncrude Analytical Aqueous Extraction of Oil Sand Method 1.7). It was found that the EPA Toxicity Characteristic Leaching Procedure generally resulted in the highest ion concentrations. The EPA method had statistically different results for three of the four tailings mixes when compared with the other three leaching methods. For Mo and Ti the EPA method always resulted in the lowest concentrations compared with the other methods, and As, Tl, and Pb sometimes resulted in the lowest concentrations. The other three leaching protocols resulted in similar dissolved ion concentrations.

REVIEW KARAKTERISTIK MEKANIK DAN TOXICITY CHARACTERISTIC LEACHING PROCEDURE BETON GEOPOLIMER

Beton Geopolimer merupakan beton yang menggunakan material anorganik produk sampingan hasil limbah padat industri yang disintesis melalui proses polimerisasi seperti fly ash, terak besi, terak nikel, dan material lainnya yang mengandung unsur Alumunium (Al) dan Silika (Si) yang tinggi. Produksi 1 ton semen Portland menghasilkan emisi gas CO2 sebesar 1 ton ke atmosfer sehingga dapat membahayakan lingkungan seperti pemanasan global. Tujuan dari studi literatur ini adalah untuk menunjukan bagaimana karakteristik mekanik pada beton geopolimer dalam penggunaan 100% produk sampingan limbah industri (ferrous dan non-ferrous) sebagai pengganti semen Portland sepenuhnya pada beton konvensional, serta meninjau dampak lingkungan yang ditimbulkan akibat penggunaan limbah tersebut dengan menggunakan analisis TCLP. Toxicity Characteristic Leaching Procedure (TCLP) merupakan prosedur untuk mengetahui kadar logam berat pada produk sampingan limbah industri (ferrous dan non-ferrous) yang dapat larut dan dapat mencemari lingkungan. Studi pustaka yang membahas material anorganik mengenai beton geopolimer secara holistik masih sedikit. Beberapa faktor yang dapat memengaruhi karakteristik mekanik beton geopolimer antara lain proporsi campuran, penggunaan admixture, pemilihan material anorganik, metode perawatan dan durasi perawatan, dan rasio larutan alkali sebagai aktivator. Proporsi campuran yang tepat dapat menghasilkan workability yang baik, kuat tekan, dan kuat tarik belah yang tinggi. Metode dan durasi perawatan dengan pemanasan (oven curing) mampu menghasilkan kekuatan mekanik yang lebih besar dibanding dengan metode perawatan suhu ruangan. Studi literatur ini diharapkan dapat memberikan pedoman dalam pengembangan beton geopolimer kedepannya bagi para peneliti dan industri.