Wastewater treatment activities in the chemical industry have generated abundant gypsum waste, classified as scheduled waste (SW205) under the Environmental Quality Regulations 2005. The waste needs to be disposed into a secure landfill due to the high heavy metals content which is becoming a threat to the environment. Hence, an alternative disposal method was evaluated by recycling the waste into fired clay brick. The brick samples were incorporated with different percentages of gypsum waste (0% as control, 10, 20, 30, 40 and 50%) and were fired at 1050 °C using 1 °C per minute heating rate. Shrinkage, dry density, initial rate of suction (IRS) and compressive strength tests were conducted to determine the physical and mechanical properties of the brick, while the synthetic precipitation leaching procedure (SPLP) was performed to scrutinize the leachability of heavy metals from the crushed brick samples. The results showed that the properties would decrease through the incorporation of gypsum waste and indicated the best result at 10% of waste utilization with 47.5% of shrinkage, 1.37% of dry density, 22.87% of IRS and 28.3% of compressive strength. In addition, the leachability test highlighted that the concentrations of Fe and Al was significantly reduced up to 100% from 4884 to 3.13 ppm (Fe) and from 16,134 to 0.81 ppm (Al), respectively. The heavy metals content in the bricks were oxidized during the firing process, which signified the successful remediation of heavy metals in the samples. Based on the permissible incorporation of gypsum waste into fired clay brick, this study promised a more green disposing method for gypsum waste, and insight as a potential towards achieving a sustainable end product.

This study aims to establish the optimal percentage of water treatment sludge (WTS) for incorporation into fired clay bricks, assessing both physical and mechanical properties as well as heavy metal leachability. Fired bricks were produced with varying proportions of WTS (0%, 5%, 10%, 20%, and 30%). Compressive strength, density, shrinkage, and water absorption were examined to evaluate physical and mechanical properties. Toxicity Characteristic Leaching Procedure was employed to investigate heavy metal concentrations, focusing on inorganic constituents. Results indicated that the optimal ratio for WTS in fired clay bricks is 5%, aligning with industry standards (BS 3921:1985). The 5% sludge incorporation yielded bricks with impressive attributes: a peak compressive strength of 25.40 MPa, density within standard limits, water absorption below 20%, and firing shrinkage under 8%. Notably, aluminum content, predominant in the sludge, decreased significantly from 74.17 ppm to 4.97 ppm. These findings suggest that WTS, when integrated into fired bricks, emerges as a viable, cost-effective, and environmentally friendly alternative. The study underscores the potential of utilizing up to 5% WTS in fired clay bricks, presenting a promising avenue for sustainable construction practices.

Ever since the pandemic of Covid-19 crisis hit all over the world, many aspects of the economy have changed especially on the healthcare issues, solid and medical waste management, as well as our food system. For a developing country like Malaysia, even though during movement control order, food wastage is not yet to be neglected. Some factors in households can influence food waste such as over shopping behaviour, panic buying that led to uneaten foods (leftovers) and household management practices such as poor planning and food storage problems. The increase in food wastage and collection generated every year will also lead to environmental pollution issues and natural resources. To overcome this issue, some researchers has been working to finding a sustainable approach to replace common practices for food waste management. Food waste will be used as industry substrates for production of valuable bioproducts and has achieved results in diversification applications and increased market demand for bioproducts. Therefore, this study discusses on current and available practices on food waste by converting it to bioproducts that enhance sustainable development. These productions is a new concept that is implemented to raise more attention to the efficient and sustainable use of resources, energy, and infrastructure to guarantee the life quality for human beings.

Sewage industry have generated huge amount of sewage sludge. It is found that the amount of sewage sludge generated by Malaysia sewerage companies has reached 5.3 million m3 per year. Sewage sludge (SS) are usually disposed into a landfill or incineration but due to the huge amount of sludge produced and limited availability of lad, it has become an environmental hazard. Thus, this research was conducted to utilize sludge that resulted from the wastewater treatment plant into fired clay brick as well as contributed to other alternative disposal method for the sludge. This research focuses on the investigation of indoor air quality of fired clay brick incorporating with SS. The SS was collected from IWK located at Senggarang and Perwira whilst clay soil was collected at Yong Peng, Johor. The characteristics of SS and clay soil were analyzed using X-ray fluorescence (XRF). From the results, it showed that SS was high with silicon oxide (SiO2) and zinc (Zn) that makes it compatible to replace clay soil as raw materials. Next, two types of sewage sludge brick (SSB) which are Senggarang brick (SB) and Perwira brick (PB) were incorporated with 0%, 1%, 5%, 10% and 20% of SS respectively. Then, the compressive strength test was conducted in accordance with the British Standard BS 3921: 1985. Based on the result, it shows that 5% of SS replacements as clay soil into fired clay brick have achieved the optimum strength. As for the indoor air quality (IAQ) test were done in walk-in stability chamber (WiSC) and the gas emission was compared with the Industry Code of Practice on Indoor Air Quality (ICOP-IAQ) through Department of Occupational Safety and Health Malaysia (DOSH, 2010). From the result, IAQ brick for SB and PB showed that up to 5% in fired clay brick were complied with the standard which below the acceptable limit that has provided for wall, column and cube formed. Thus, as a conclusion this method provided an alternative disposal method for the SS whilst producing a new low-cost building material with no negative effect to human as well as benefit to the environment.

There is about 2.01 billion metric tons of municipal solid waste (MSW) produced annually and organic waste constitutes of a major portion from total waste generation worldwide. This current circumstance not only create extra burden on the landfill, but also causing some environmental issues such as greenhouse gases emission, odor emission and leachate production. Therefore, a sustainable and pro-environmental of organic waste disposal solution is acknowledged by composting practice. However, organic waste consists of some significant properties include high in salt, oil, nitrogen and moisture content. All of these properties contributing difficulties on the efficiency of organic waste composting process. In previous studies, researchers had studied various bulking agents such as biochar, sawdust, lime and others in order to optimize the efficacy of composting process. Nevertheless, utilization of zeolite as bulking agent in composting process is getting famous in the recent years due to its unique physiochemical characteristics. Hence, this article attempts to review the potential of zeolites in optimizing the composting process for better understanding of the mechanism as well provides valuable insights for sustainable organic waste management practice.

The increase in environmental pollution is largely reflected by industrial activities, urbanization and population development. Due to these activities, it has produced millions of tons of food waste every day. Food waste has become a serious problem in the world as most countries are also concerned about the challenge of managing food waste. Studies suggested that composting is a better method to control and reduce the amount of food waste as it is easy to apply and can be harvested in a short period. Composting also ensures a promising return in prolonging the life span of landfills, as well as reduces the leakage of leachate into groundwater.