In this study, tannin-based natural coagulant was used to treat stabilized landfill leachate. Tannin modified with amino group was utilized for the treatment process. Central composite design (CCD) was used to investigate and optimize the effect of tannin dosage and pH on four responses. The treatment efficiency was evaluated based on the removal of four selected (responses) parameters; namely, chemical oxygen demand (COD), color, NH3–N and total suspended solids (TSS). The optimum removal efficiency for COD, TSS, NH3–N and color was obtained using a tannin dosage of 0.73 g at a pH of 6. Moreover, the removal efficiency for selected heavy metals from leachate; namely, iron (Fe2+), zinc (Zn2+), copper (Cu2+), chromium (Cr2+), cadmium (Cd2+), lead (Pb2+), arsenic (As3+), and cobalt (Co2+) was also investigated. The results for removal efficiency for COD, TSS, NH3–N, and color were 53.50%, 60.26%, and 91.39%, respectively. The removal of selected heavy metals from leachate for Fe2+, Zn2+, Cu2+, Cr2+, Cd2+, Pb2+, As3+ and cobalt Co2+ were 89.76%, 94.61%, 94.15%, 89.94%, 17.26%, 93.78%, 86.43% and 84.19%, respectively. The results demonstrate that tannin-based natural coagulant could effectively remove organic compounds and heavy metals from stabilized landfill leachate.

Leachate is a complex liquid that is often produced from landfills, and it contains hazardous substances that may endanger the surrounding environment if ineffectively treated. In this work, four leachate treatment applications were examined: combined leachate/palm oil mill effluent (POME) (LP), leachate/tannin (LT), pre-(leachate/tannin) followed by post-(leachate/POME) (LT/LP), and pre-(leachate/POME) followed by post-(leachate/tannin) (LP/LT). The aim of this work is to evaluate and compare the performance of these treatment applications in terms of optimizing the physicochemical parameters and removing heavy metals from the leachate. The highest efficiency for the optimization of the most targeted physicochemical parameters and the removal of heavy metals was with the LP/LT process. The results are indicative of three clusters. The first cluster involves raw leachate (cluster 1), the second contains LP and LP/LT (cluster 2), and the third also consists of two treatment applications, namely, LT and LT/LP (cluster 3). The results demonstrate that LP/LT is the most appropriate method for leachate treatment using low-cost agro-industrial materials.

In this study, leachate collection and processing system in Ampar Tenang Closed Landfill (ATCL) and its impact on both groundwater and surface water was evaluated. Samples from three locations in leachate processing system (Collection, aeration and stabilization ponds), groundwater and surface water were collected and tested for twenty-one parameters covering nine heavy metals (Fe Correlation analysis for landfill leachate ponds, groundwater and surface water showed different patterns of relationships between all possible combinations of two parameters. Similarity and dissimilarity were studied through cluster analysis, three clusters were found to entirely separate the collection pond (cluster 1) while the two ponds were clustered with groundwater samples (cluster 2) and the third cluster is for the surface water. This study shows the benefit of statistical analysis such as correlation analysis and cluster analysis for evaluation and interpretation of landfill data to understand the behavior of the selected parameters and to have a clear picture about the pattern of the relationship for effective landfill management. ABSTRAKDalam kajian ini, sistem pengumpulan dan pemprosesan air larut resap di Tapak Pelupusan Tertutup Ampar Tenang (ATCL) dan kesannya terhadap air bawah tanah dan air permukaan telah dinilai. Sampel daripada tiga lokasi dalam sistem pemprosesan air larut resap (kolam pengumpulan, pengudaraan dan penstabilan), air bawah tanah dan air permukaan diperoleh dan diuji untuk dua puluh satu parameter iaitu sembilan jenis logam berat (Fe dan oksigen terlarut (DO)). Analisis korelasi untuk kolam air larut resap, air bawah tanah dan air permukaan menunjukkan corak hubungan yang berbeza antara semua kemungkinan gabungan dua parameter. Persamaan dan ketidaksetaraan dikaji melalui analisis kelompok dan tiga kelompok didapati memisahkan kolam pungutan sepenuhnya (kelompok 1) manakala dua kolam berkumpul dengan sampel air bawah tanah (kelompok 2) dan kelompokketiga adalah untuk air permukaan. Analisis statistik seperti analisis korelasi dan analisis kelompok untuk penilaian dan pentafsiran data tapak pelupusan sampah dapat membantu dalam memahami ciri-ciri parameter terpilih dan untuk mendapatkan gambaran yang jelas mengenai corak perhubungan bagi pengurusan tapak pelupusan sampah yang berkesan.Kata kunci: Air larut resap; analisis kelompok; logam berat; matriks korelasi; statistik diskriptif; tapak pelupusan sampah

Sanitary landfilling is the most common method of removing urban solid waste in developing countries. Landfills contain high levels of organic materials, ammonia, and heavy metals, thereby producing leachate which causes a possible future pollution of ground and surface water. Recently, agricultural waste was considered a co-substratum to promote the biodegradation of organics in industrial wastewater. The use of low-cost and natural materials for wastewater treatment is now being considered by many researchers. In this study, palm oil mill effluent (POME) was used for treating stabilized leachate from old landfill. A set of preliminary experiments using different POME/leachate ratios and aeration times was performed to identify the setting of experimental design and optimize the effect of employing POME on four responses: chemical oxygen demand (COD), total suspended solids (TSS), color, and ammoniacal nitrogen (NH3-N). The treatment efficiency was evaluated based on the removal of four selected (responses) parameters. The optimum removal efficiency for COD, TSS, color, and NH3-N was 87.15%, 65.54%, 52.78%, and 91.75%, respectively, using a POME/leachate mixing ratio of 188.32 mL/811.68 mL and 21 days of aeration time. The results demonstrate that POME-based agricultural waste can be effectively employed for organic removal from leachate.

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