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The leather tanning process, a complex process and consists of several steps, where the process involves a large number of water and chemical substances which can cause pollution. The current study provided an investigation on the activated carbon derived from Palm Kernel Cake (PKC) used in the adsorption technology. This activated carbon was considered for reducing total chromium content and BOD, increasing the pH and color of the tanneries wastewater, especially in chrome tanning process. Four variations of activated carbon weight (1 g, 2 g, 3 g, 4 g, and 5 g) were tested in three different temperatures (40 °C, 50 °C, and 60 °C) for 30 minutes. After that, the tannery wastewater, which had been adsorbed, was allowed to stand for 24 hours and then filtered. Next, observations on the total chromium content, Biological Oxygen Demand (BOD) level, pH, and color of the obtained filtrate were performed. The results showed that the activated carbon successfully adsorbed the pollutant compounds by reducing the total chromium and BOD levels, increasing the pH and color of tanneries wastewater. In more detail, the findings revealed that the activated carbon could raise the pH level to 6.6, reduced BOD levels to 50.7 mg/L with 87.03% of efficiency, and reduced the total chrome content to 1.03 mg/L with 99.87% of efficiency. Besides, the process resulted in tannery wastewater discoloration, from what was originally dark blue to colorless. To conclude, the adsorption for chrome tanning waste adsorption was found performing optimally by using 4 gram of activated carbon at 50 °C.

This study aims to determine the amount of chrome that come out together with tannery waste in a tanned combination process of chrome-gambier and chrome-mimosa. the process research performed by 2 stages. The 1st stage using chrome with 5 concentration, they were 2,4,6 and 8 %. Then it followed by the 2nd stage tanning process by using vegetable tanning, gambier and mimosa, with each 7% and 9% concentration. The results showed that the combination of chrome-gambier tanned at the same concentration disposed chromium waste less than the combination of chrome-mimosa tanned. The lowest total chrome waste on the chrome-gambier tanning combination was 3.9 ppm at 2% chromium and 7% gambier concentration and the highest was 146.6 ppm at 8% chromium and 9% gambier concentrations. The lowest total chrome waste on the combination of chrome-mimosa tanning was 2.2 ppm at 2% chromium and 7% mimosa concentration and the highest was 170.4 ppm at 8 % chromium and 9% mimosa concentration. The 2ndtanning, was combination tanning process, chrome-gambier able to reduce chromium levels more than the chrome-mimosa tanning.ABSTRAKPenelitian ini bertujuan untuk mengetahui jumlah krom yang ikut terbuang bersama limbah proses penyamakan kulit yang di samak kombinasi krom-gambir dan krom-mimosa. Pelaksanaan penelitian proses penyamakan kulit dilakukan dengan 2 tahap. Tahap I menggunakan krom dengan 5 variasi konsentrasi yaitu 2, 4, 6 dan 8%. Setelah penyamakan tahap I kemudian dilanjutkan penyamakan tahap II dengan menggunakan penyamakan nabati, gambir dan mimosa, dengan variasi konsentrasi masing-masing 7 dan 9%. Hasil penelitian menunjukkan bahwa perlakuan penyamakan kombinasi krom-gambir pada konsentrasi yang sama menghasilkan limbah krom yang lebih sedikit dibandingkan dengan samak kombinasi krom-mimosa. Jumlah limbah krom pada penyamak kombinasi krom-gambir terendah adalah 3,9 ppm pada konsentrasi krom 2% dan gambir 7% dan tertinggi 146,6 ppm pada konsentasi krom 8% dan gambir 9%. Jumlah limbah krom pada penyamak kombinasi krom-mimosa terendah adalah 2,2 ppm pada konsentrasi krom 2% dan mimosa 7% dan tertinggi 170,4 ppm pada konsentasi krom 8% dan mimosa 9%. Penyamakan tahap II, yang merupakan samak kombinasi, krom-gambir dapat menurunkan kadar krom lebih banyak dibandingkan kombinasi krom-mimosa.

Abstract: The leather industry faces very challenging task because of the regulations enforced by the various pollution control bodies to maintain the discharged norms of the chemical in the treated water. The pollution due to the use of chromium and other chemicals in the leather industry is critically analyzed for the harmful effects. Many studies have been undertaken to optimize the amount of chemicals used in leather processing. The pollution due to chromium is one of the major constraints in the leather processing operation. Chrome recovery and reuse methods have become the compulsory recovery methods in the leather industry to recover and reuse the chromium present in the effluent. Several precipitation methods are emerging but still they are not feasible. In this paper, an attempt has been made to recover the chromium present in spent tan liquor using neutralized wattle extract. The wattle extract at different pH conditions (pH 7, 8, and 9) was used for recovery of chromium. The neutralized wattle extract was made to react with chromium in the spent liquor and allowed to settle for a period of 6h. Major amount of chromium settles at the bottom leaving minimal amount in the supernatant. The chrome was recovered and reused for tanning the pelt. The wattle extract that was left in the tanning bath was reused for post-tanning process as a retanning agent. Therefore, complete utilization of the chromium and wattle extract has been achieved in this work. It has also been noticed that increased level of chrome exhaustion of 85% and 87% (precipitate and supernatant) in experimental leather could be obtained in comparison with the exhaustion of 74% in control sample. The physical strength and color properties of the experimental leather were comparable to the control leather. The overall results show that the recovered chromium can be well used for tanning purpose to obtain the leather of comparable properties. [Copyright &y& Elsevier]