Pusat Pengajian Kejuruteraan Awam - Tesis

Browse

Browsing Pusat Pengajian Kejuruteraan Awam - Tesis by Author "Abd Hamid, Mohd Azhar"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Publication
    Zeolite augmented electrocoagulation process for removing ammonia and colour in saline landfill leachate
    (2021-05-01)
    Abd Hamid, Mohd Azhar
    Landfill leachate is referred to as high strength wastewater where its treatment via a single process is rather inconvenient. The generation of saline landfill leachate, which is dark in colour, composed of several high concentration toxic substances such as ammonia and COD, as well as having low BOD level, is affecting the ecosystem and human health. Hence, this study was introduced to evaluate the capability of the zeolite augmented electrocoagulation process (Z+EC) in the removal of ammonia and colour pollutants from the semi-aerobic saline Pulau Burung Landfill Site (PBLS) leachate. Observation on the leachate samples collected from January until December 2019 at PBLS, which is located adjacent to the shoreline, revealed a composition of high concentrations of ammonia (3889 mg/L), colour (8240 Pt-Co), and salinity (17.53 ppt). The BET physical analysis conducted classified the zeolite (Z) structure as mesoporous with a surface area of 49.3371 m2 /g, pore volume of 0.0927 cm3 /g, and pore diameter of 7.5141 nm, as supported by the FESEM images (5kX) of heterogeneous porous zeolite structure. The chemical characterizations of XRF, XRD, and FT-IR portrayed efficient ion exchange of cations (Na+ , K+ , Ca2+, Mg2+) on the monoclinic structured clinoptilolite (Si/Al = 5.68, > 4) of primarily hydroxyl groups (O-H and T-O). The adsorption process using zeolite was highly effective in eliminating ammonia (57%) but less likely for colour removal (18%), achievable at optimum variables of 75 – 150 µm particle size, zeolite dosage of 120 g/750 mL, contact time of 60 min, pH 9, and agitation speed of 250 rpm. Nevertheless, ammonia and colour adsorptions fulfilled the chemical adsorption mechanism on a homogenous xxvi surface based on the correlation coefficients (R2 ≈ 1), which fitted the Langmuir isotherm (0.9843, 0.9764) and P2O kinetic (0.9836, 0.9752) models better than the Freundlich and P1O models. Excellent removal of the colour of up to 71% but low ammonia removal of only 19% were achieved in optimum electrocoagulation (EC) reactor system under the influences of natural leachate salinity and several main parameters including electrode type (Al), electrode size (5 cm), interelectrode distance (3 cm), current density (540 A/m2 ), electrolysis duration (60 min), pH (8), and stirring speed (150 rpm). The combined Z+EC treatment had successfully enhanced the simultaneous removals of ammonia (70%) and colour (88%). Response surface methodology (RSM) was adopted to optimize the Z+EC treatment efficacy (Error < 2%) in eliminating ammonia (71%) and colour (90%) by considering the critical parameters of zeolite dosage (105 g/750 mL), current density (600 A/m2 ), reaction time (60 min), and pH (8.20). The integration of the Z+EC treatment in a sequencing batch reactor (SBR) was established with adsorbent regeneration in sustaining the capability and dosage of zeolite in a continuous and unique single treatment reactor (Z+EC-SBR). The continuous operation of Z+EC-SBR treatment (5 hours) exhibited maximum removals of ammonia (83%) and colour (94%) with produced treated effluent of 3500 mL. Based on the findings of this study, it is evident that the Z+EC treatment is a highly potential process for the simultaneous removals of high strength ammonia and colour in saline landfill leachate.