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In Malaysia, there are some accumulation of sugar refinery byproducts with a lot of this material not being utilized in a productive manner, while, these byproducts had the great potential when mixed into agricultural soils as organic fertilizer with many of benefits that can improve soil health, and sustainable agronomic productivity. Pressmud or known as filter cake is a by-product of sugar industry and for every 100 tons of sugarcane crushed about 3 tons of pressmud cake is left behind as by-product. This studies carried out on this material have not properly summarized their characteristics properties that they can be used as aid for future works. Data from tests involving pressmud samples from Malayan Sugar Manufacturing (MSM) Prai Berhad, Penang which was part of a larger collection was analyzed. The physicochemical properties of pressmud characterization as well as leaching test were carried out. The physicochemical and engineering properties involved compaction behavior, permeability, cation exchange capacity (CEC), compressive stress test and its surface functional groups. The leaching test method included batch equilibrium test and column test. The optimum value of water content in pressmud was determined in the compaction test. It was found out that pressmud has higher optimum water content value was observed. The permeability test of pressmud gave value in ranges of 1.84 x 10-5 cm/s. The Cation Exchange Capacity (CEC) of pressmud indicated value in the range of 99 to 101 meq/100 g. The high cation exchange capacity indicated that pressmud was believed to be primarily responsible for sorption of metal ions. It can be concluded that pressmud having the capability to remove heavy metals through CEC process. Pressmud also showed higher compressive strength value. Batch equilibrium test glaringly showed that pressmud have the capability to remove from 53.6%-93.8% metal removed from metal solutions for Chromium (Cr), Copper (Cu), Manganese (Mn), Nickle (Ni), Lead (Pb) and Zinc (Zn). From the result of column test, pressmud alone was able to retain efficiently all the heavy metals as these metals did not reach 1 (relative concentration) until 10 pore volume (PV.) indicating that pressmud was a good mixture material as it can assist in adsorption of heavy metals. Based on the characterization study, removal efficiency and column test, pressmud has great potentiality to be used as an additional material in soil amendments to enhance soil fertility and strength ability.

Municipal solid waste landfills are major sources of environmental pollution. This study evaluated heavy metal concentrations in soils around Pulau Burung Landfill, Penang, Malaysia, to determine the pollution potential of a landfill. Soil samples were collected at depths of 0–20 cm (top), 20–40 cm (center) and 40–60 cm (bottom) around the landfill and at a control site and characterized for various properties and concentrations of Lead (Pb) and Zinc (Zn). Samples of daily soil cover, collected from the same sites where soil samples were collected, were also analyzed for several of heavy metals analysis. The soils were silty sand, mostly acidic (4.45) with low organic matter content (0.41%) and cation exchange capacity (3.15-3.19 meq/100 g). Other basic physico-chemical and adsorption properties were conducted on soil indicated that soil alone is not effective to be used in the landfill to support the pollutant for a long time. Heavy metals concentrations (as background data) in the soils followed the order Iron (Fe) > Zinc (Zn) > Manganese (Mn) > Lead (Pb) > Arsenic (As) > Chromium (Cr) > Cadmium (Cd) > Copper (Cu) > Nickle (Ni) with samples from around the landfill having higher concentrations especially Iron, (Fe) and Zinc, (Zn). For soil profile contribution, heavy metal enrichment was highest at a depth of 40–60 cm. In short, soil alone cannot retain and minimize the migration of heavy metals in landfill based on the results of this study including removal efficiency test. Monitoring of environments around active landfills needs to be ongoing to mitigate negative impacts on humans and the environment.

Landfill leachate generation is one of the main problems from sanitary landfill. Chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), and color are among the most problematic parameters in stabilized leachate. In this regard, dedicated treatment facilities are required before leachate can be discharged into the environment. The performance of the combined ozonation (O3) and zirconium tetrachloride (ZrCl4) to treat two types of stabilized leachate was investigated during this study. Leachate samples were collected from an anaerobic stabilized leachate (Alor Pongsu Landfill Site, APLS) and semi-aerobic stabilized leachate (Pulau Burung Landfill Site, PBLS). Zirconium tetrachloride dosage was determined as 1 g/1 g (COD/ZrCl4 ratio) and then added to the leachate samples with 60 min ozonation at natural leachate pH (8). COD, color, and NH3-N were removed from the APLS sample at 33%, 70%, and 53% rates, respectively, whereas 48%, 75%, and 69%, respectively, from the PBLS samples. Ozone consumption was also calculated with the highest value (3.81 Kg O3/ Kg COD) reported in PBLS, whereas the lowest value (2.32 Kg O3/ Kg COD) was reported in APLS. Biodegradability of (BOD5/COD) was investigated and improved from 0.07 to 0.08 for the APLS samples and 0.05 to 0.11 for the PBLS samples after leachate oxidation. Results showed that the performance of O3/ZrCl4 oxidation is more efficient in treating semi-aerobic stabilized leachate than anaerobic stabilized leachate Moreover, the combined method proved to be more efficient in remediating leachate compared with ozone and zirconium treatment alone.