Solid waste management in developing countries including Malaysia is dominated by waste dumpsites which have a high possibility of transporting organic and inorganic pollutants to the underlying groundwater and surface water within the surrounding area. The objective of this study is to characterise the landfill leachates and its surrounding groundwater and river water quality and metals concentrations, namely arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) from Beris Lalang, Kelantan. Nine sampling points were collected within the dumpsite for analysis of in-situ: dissolved oxygen (DO), pH, total dissolved solids (TDS), conductivity, turbidity and ex-situ; Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and Suspended Solids (SS) and the results were compared with permissible limits. As and Pb in groundwater samples were collected from the surface of two dug grounds within the vicinity of the dumpsites exceeded the standard of Ministry of Health. Cr, Cu and Pb in leachates exceeded Environmental Quality Act (EQA, 1974)’s standard, whereas Ni, Pb and Zn in surface water of Gali River exceeded the limit of class III National Water Quality Standard (NWQS). Exceeding metals concentration in leachates and its surrounding groundwater and river water relative to their respective standards points out toward potential leachate migration to the waterbodies within the surrounding vicinity of Beris Lalang dumpsite. This study provides the initial baseline data and preliminary monitoring assessments as a first step towards improving water security and waste management in Kelantan.
This paper critically reviews the impacts of supplementing trace elements on the anaerobic digestion performance. The in-depth knowledge of trace elements as micronutrients and metalloenzyme components justifies trace element supplementation into the anaerobic digestion system. Most of the earlier studies reported that trace elements addition at (sub)optimum dosages had positive impacts mainly longer term on digester stability with greater organic matter degradation, low volatile fatty acids (VFA) concentration and higher biogas production. However, these positive impacts and element requirements are not fully understood, they are explained on a case to case basis because of the great variance of the anaerobic digestion operation. Iron (Fe), nickel (Ni) and cobalt (Co) are the most studied and desirable elements. The right combination of multi-elements supplementation can have greater positive impact. This measure is highly recommended, especially for the mono-digestion of micronutrient-deficient substrates. The future research should consider the aspect of trace element bioavailability.