Biochar as Cement Replacement to Enhance Concrete Composite Properties: A Review

In recent years, concrete has been accessible and economical in the construction industry, resulting in high demand for its components. Cement is known for its negative impact on the environment, which has led researchers to investigate alternative supplementary materials. Recently, biochar has been proposed as a replacement to cement in small amounts, with an optimum amount of 0.08–5, resulting in increased strength and enhancement of other properties of concrete composites. The biochar production process and its components are more economical and environmentally friendly than that of cement. In this review, we focus on research highlighting the properties of biochar that aid in the enhancement of biochar mortar and concrete composite properties. We explore properties of biochar such as water absorption, as well as compressive, flexural and tensile strength. Progress has been made in research on biochar concrete composites; however, additional investigations are required with respect to its carbon-sequestering abilities and life cycle assessment for its production process

Treatment of palm oil mill effluent (POME) by coagulation flocculation process using peanut–okra and wheat germ–okra

Coagulation–flocculation has been proven as one of the effective processes in treating palm oil mill effluent (POME), which is a highly polluted wastewater generated from palm oil milling process. Two pairs of natural coagulant–flocculant were studied and evaluated: peanut–okra and wheat germ–okra. This research aims to optimize the operating parameters of the coagulation flocculation process in removing turbidity, total suspended solid and chemical oxygen demand (COD) from POME by using a central composite design in the Design Expert® software. Important parameters such as operating pH, coagulant and flocculant dosages were empirically determined using jar test experiment and optimized using response surface methodology module. Significant quadratic polynomial models were obtained via regression analyses (R2) for peanut–okra (0.9355, 0.9534 and 0.8586 for turbidity, total suspended solids and COD removal, respectively) and wheat germ–okra (0.9638, 0.9578 and 0.7691 for turbidity, total suspended solids and COD removal, respectively). The highest observed removal efficiencies of turbidity, total suspended solids and COD (92.5, 86.6 and 34.8%, respectively, for peanut–okra; 86.6, 87.5 and 43.6%, respectively, for wheat germ–okra) were obtained at optimum pH, coagulant and flocculant dosages (pH 11.6, 1000.1 mg/L and 135.5 mg/L, respectively, for peanut–okra; pH 12, 1170.5 mg/L and 100 mg/L, respectively, for wheat germ–okra). The coagulation flocculation performance of peanut–okra and wheat germ–okra were comparable to each other. Characterizations of the natural coagulant–flocculant, as well as the sludge produced, were performed using Fourier transform infrared, energy-dispersive X-ray spectroscopy and field emission scanning electron microscope. More than 98% of water was removed from POME sludge by using centrifuge and drying methods, indicating that a significant reduction in sludge volume was achieved.</p

A numerical modelling on the effectiveness of bioretention system for dengue control

Conventional urban drainage structures that store water over time are habitat for the mosquito larvae. Appropriate stormwater management practices can help in preventing the breeding of the mosquito larvae. Thus, a study was conducted to evaluate the performance of a proposed bioretention system in controlling dengue at the campus university in Semenyih, Malaysia. The XP Stormwater Management Model (XPSWMM) was applied for the numerical analysis and modelling in this study. A series of simulations were carried out for the ARI of 2, 5, and 10 years to evaluate the performance under the two scenarios of conventional drainage system and bioretention system, taking into considerations the maximum water depth (stages), inflow volume from runoff, and pollutant load reduction from the sub-catchments to control the breeding of aedes mosquitoes. The simulated results indicated that the bioretention system is capable of reducing the maximum water depth (stages) of the sub-catchments to up to 85% as compared to the conventional drainage system. In addition, the reduction of the inflow volume from runoff ranges from 0.3% to 0.5% and the pollutant loads reduced by approximately 100%. The reduction in water depth and inflow volume will result in mitigating the risk of water stagnancy within all the sub-catchments of the study area. The simulated results demonstrated that bioretention system could be used effectively to control the breeding of mosquitoes. Hence, the findings obtained in this study can assist the decision makers of the university in the adoption of bioretention system to control dengue within the campus