The present study was conducted to determine the potential of utilizing the FeSO₄·7H₂O waste from the titanium manufacturing industry as an effective coagulant for treating industrial effluent. In this study, the secondary rubber processing effluent (SRPE) was treated using ferrous sulfate (FeSO₄·7H₂O) waste from the titanium oxide manufacturing industry. The FeSO₄·7H₂O waste coagulation efficiency was evaluated on the elimination of ammoniacal nitrogen (NH₃-N) and chemical oxygen demand (COD) from SRPE. The central composite design (CCD) of experiments was employed to design the coagulation experiments with varying coagulation time, coagulant doses, and temperature. The coagulation experiments were optimized on the optimal elimination of NH₃-N and COD using response surface methodology (RSM). Results showed that coagulant doses and temperature significantly influenced NH₃-N and COD elimination from SRPE. The highest NH₃-N and COD removal obtained were 98.19% and 93.86%, respectively, at the optimized coagulation experimental conditions of coagulation time 70 min, coagulant doses 900 mg/L, and temperature 62 °C. The residual NH₃-N and COD in treated SPRE were found below the specified industrial effluent discharge limits set by DoE, Malaysia. Additionally, the sludge generated after coagulation of SRPE contains essential plant nutrients. The present study’s finding showed that FeSO₄·7H₂O waste generated as an industrial byproduct in a titanium oxide manufacturing industry could be utilized as an eco-friendly coagulant in treating industrial effluent.

Phytoremediation is an eco-friendly, economical method that uses plants to remediate pollutants in soil, water, and air. This chapter examines the fundamental processes of phytoremediation, including phytoextraction, phytostabilization, phytodegradation, phytovolatilization, and rhizofiltration, that allow plants to absorb, degrade, stabilize, or filter contaminants such as heavy metals and organic pollutants. The work explores the selection of suitable plant species, emphasizing hyperaccumulators, and provides examples of cases that exemplify effective practical applications. This chapter analyzes current biotechnological breakthroughs that have improved the efficacy of phytoremediation, particularly via the use of genetically modified plants. Furthermore, it highlights the ecological and economic advantages of this green remediation method, while outlining prospective research opportunities to enhance its efficacy and face complex pollution issues. The chapter discusses phytoremediation’s significant role in sustainable environmental management and pollution mitigation through thorough exploration.

The study was carried out to evaluate the effect of combining pressmud and rice husk in the removal efficiencies of heavy metals in acidic synthetic wastewater. The ratios of pressmud to rice husk were varied at different percentages of weight ratio (0%, 20%, 40%, 60% 80% and 100%) and removal of heavy metals concentrations was observed. The result showed that the removal efficiency was increased with the addition of pressmud by up to almost 100 %. Pressmud alone was able to remove 95% to 100% of heavy metals while rice husk alone managed to remove only 10 % to 20% of heavy metals. The study also demonstrated that pressmud behaved as a natural acid neutralizer. Hence, the initial pH of the synthetically prepared acidic wastewater which was below 2 also was increased to pH ranging from 6 to 8.