Kajian ini dilakukan untuk menilai prestasi zeolit semulajadi dan zeolit pengaktifan haba dalam merawat air larut lesapan dari tapak pelupusan Alor Pongsu, sebagai tapak kajian kes. Pengambilan sampel air larut lesapan dilakukan sebanyak tiga kali dari 19th Februari hingga 25th Mac 2019 dikuti pencirian parameter utama larut lesapan. Manakala, media zeolit semulajadi dan zeolit pengaktifan haba dicirikan menggunakan X-Ray Diffraction (XRD), X-Ray Fluorescene (XRF), Scanning Electron Microscopy (SEM) dan Brunauer-Emmelt-Teller (BET). Kemudian, zeolit disediakan dalam saiz 2-4mm dan digunakan sebagai media penjerap. Kesan dos penjerap dan pH terhadap rawatan telah dikaji. Kajian penjerapan zeolit semulajadi dan pengaktifan haba telah dijalankan dengan menggunakan model isoterma Langmuir dan Freundlich. Perbandingan prestasi rawatan dilakukan antara zeolit semulajadi dan zeolit yang diaktifkan pada suhu 150°C, 200°C serta 250°C. Keputusan menunjukkan bahawa air larut lesapan mempunyai nilai pH 8.09, suhu 25.5°C, nitrogen ammonia 1080mg/L, oksigen terlarut 1.0mg/L, Permintaan Oksigen Kimia 3743mg/L, warna jelas 16250PtCo, warna sebenar 13077PtCo, zeta potensial -21.0mV dan jumlah pepejal terampai 388mg/L. Berdasarkan analisis XRD dan XRF, zeolit telah dikenalpasti sebagai kuartza. Hasil kajian menunjukkan bahawa penggunaan zeolit yang diaktifkan pada suhu 150°C adalah optimum untuk rawatan. Menggunakan zeolit semulajadi pada dos 10g, penyingkiran nitrogen ammonia pada pH optimum 7 adalah 55.8%. Walau bagaimanapun, pada pH optimum 4, penyingkiran COD dan warna sebenar adalah masing-masing 24.3% dan 73.8%, pada dos yang sama (10 g). Untuk zeolit yang diaktifkan pada suhu 150°C, pada dos optimum 10 g, penyingkiran nitrogen ammonia adalah 67.0 % pada pH optimum 8. Namun begitu, pada pH optimum 4, penyingkiran COD adalah 46.3%, dan pengurangan warna sebenar adalah 91.4% pada pH optimum pH 5; kedua-duanya pada dos yang sama (10g). Peningkatan penyingkiran selepas pengaktifan haba adalah sebanyak masing-masing 11.2%, 22%, dan 17.5%, untuk nitrogen ammonia, COD, dan warna sebenar. Kapasiti penukaran ion oleh zeolit juga dijangka menyumbang terhadap penyingkiran bahan pencemar. Analisis penjerapan isotherma menunjukkan bahawa kedua-dua isotherma Langmuir dan Freundlich berpadanan dengan data eksperimen. Secara umumnya, model Freundlich dapat menggambarkan data keseimbangan yang lebih baik berbanding dengan model Langmuir berdasarkan nilai-nilai R2 yang tinggi bagi parameter COD, NH3-N dan warna sebenar.
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This study was undertaken to determine the performance of raw zeolite and heat activated zeolite to treat the landfill leachate from Alor Pongsu landfill, as a case study site. The landfill leachate was collected for three times between 19th February and 25th March 2019 and then was characterized for the main leachate parameters. The raw zeolite was characterized by the X-ray diffraction, X-ray fluorescence, Scanning electron microscopy and Brunauer-Emmett-Teller instrument, later sieved to size 2-4mm and was used as the adsorbent. Batch studies were undertaken at different adsorbent dosages and pH values. The Langmuir and Freundlich isotherm parameters were also determined. The performance of raw zeolite was compared with the activated zeolite, heated at 150°C, 200°C and 250°C. Results indicated that the average leachate parameters monitored were pH 8.09, temperature 25.5°C, ammoniacal nitrogen 1080mg/L, dissolved oxygen 1.0mg/L, chemical oxygen demand 3743mg/L, apparent colour 16250PtCo, true colour 13077PtCo, zeta potential -21.0mV and total suspended solid 388mg/L. Based on the X-ray diffraction and X-ray fluorescence analysis, the zeolite was identified as quartz. Based on the batch results, the activated zeolite heated at 150°C showed better performance. Using raw zeolite, at an optimum dosage of 10 g, the ammoniacal nitrogen removal was 55.8% at an optimum pH 7. However, at an optimum pH 4, the removal for COD and the true color was 24.3% and 73.8%, respectively, at the same dosage (10 g). For activated zeolite heated at 150°C, at optimum dosage of 10 g, the ammoniacal nitrogen removal was 67.0 % at an optimum pH 8. However, at an optimum pH 4, the removal for COD was 46.3%, and the reduction of true color was 91.4% at an optimum pH 5; both at the same dosage (10 g). The improvements in the removal performance after heat treatment were 11.2%, 22%, and 17.5%, respectively, for ammoniacal nitrogen, COD and true colour. The cation exchange capacity of the zeolite is also expected to contribute to the removal of the pollutants. The adsorption isotherm analysis revealed that both Langmuir and Freundlich isotherms fitted well with the experimental data. However, the Freundlich isotherm model is more suitable than Langmuir isotherm for evaluating the adsorption equilibrium required for COD, NH3-N and true colour as verified by the high R2 values.
Ammoniacal nitrogen removal from landfill leachate by heat activated zeolite / Yap Wei Keat