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The amount of waste is increasing daily; however, the available land area is limited. This problem can be overcome by segregating waste and other alternatives by accelerating landfill stabilization using landfill bioreactors. In this study, anaerobic bioreactor A with daily use of water and the leachate, anaerobic bioreactor B with the addition of water and reuse of the leachate daily, and a control bioreactor with the addition of water were used. The parameters measured were the pH, temperature, humidity, chemical oxygen demand (COD), and biochemical oxygen demand (BOD) of the leachate. The reuse of the leachate and addition of water to the bioreactor accelerated waste degradation and caused high humidity. The average COD and BOD in each bioreactor on day 40 were stable. On day 45, the BOD (74.925 mg/L) was below 100 mg/L and the average COD (781 mg/L) was stable below 1000 mg/L. These results were for all bioreactors except for the control bioreactor, which only received water addition treatment; its COD value was below 1000 mg/L on day 50, at 989 mg/L. Waste decomposition was stabilized, with the BOD below 100 mg/L and the COD below 1000 mg/L.

Tamarindus indica shell biochar is employed as an alternate adsorbent precursor for the removal of heavy metal ions from aqueous solutions. It investigated the Tamarindus indica shell biochar's capacity to absorb chromium (Cr), copper (Cu), and Lead (Pb). This study showed the extensive explored how biosorption experimental limitations counting primary metal attentiveness, adsorbent dosage, temperature, and contact time affect the process. The complete analysis of the Tamarindus indica shell's adsorption capability with respect to chromium, copper, and nickel removal was conducted using a batch adsorption procedure. Determining the amount of heavy metal removal in the aqueous solution proceeded by Gas Chromatography (GC). The experimental data analyzed using the Yoon Nelson and Thomson models to regulate the equilibrium isotherms. The optimal parameters for the overall adsorption model were determined by using ANOVA. Investigate the adsorbent's surface area to determine the presence of heavy metal presents using SEM, XRD, and FTIR techniques. Each researched heavy metal's adsorption capability is listed below: Cr = 6.07 mg/L, Cu = 5.53 mg/L and Pb = 5.497mg/L with a removal percentage of 64%, 92% and 78%, respectively. The results showed that biochar generated from Tamarindus indica shells is an effective adsorbent for removing copper from aqueous solutions but not a viable biosorbent for removing chromium. Also, the regenerated column's adsorption capability was examined. The outcomes of the research demonstrated that bio-char, which produced from Tamarindus indica shell can be employed as an efficient and reasonably priced adsorbent to remove heavy metal ions from aqueous solutions.

Developing an efficient sorbent for removing the highly toxic Cr(VI) is very important, which tackles the threat of Cr(VI) pollution to ecological environment and human health. Herein, a cationic covalent organic framework bearing cationic guanidine (named TATGCl) was synthesized from terephthalaldehyde (TA) and triaminoguanidinium chloride (TGCl), and exploited to discard Cr(VI) from water. The Cr(VI) removal ability of TATGCl strongly relies on the aqueous pH, and is strong at low pH. The removing ability is obviously also affected by ionic strength. The Cr(VI) sorption process on TATGCl obeys pseudo-second-order and Langmuir models. Batch adsorption experiments and characterization show that the guanidine group on the skeleton of TATGCl is pivotal in capturing Cr(VI) through hydrogen bonding and anion exchange/electrostatic interaction. A reduction mechanism also exists in the Cr(VI) disposal by a small amount of unreacted aldehyde group of TATGCl. The large removal ability makes TATGCl a prospective candidate for discarding Cr(VI) from water.

Tungsten (W) is an emerging contaminant because of its potential toxicity to humans, and biochar (BC) is widely used for soil heavy metal remediation. However, W-biochar-plant interactions remain unknown. The objective of the study was to evaluate the effect of rice-husk BC on W uptake by lettuce. Different levels of BC (0%, 1%, 2% and 5% w/w) were incorporated into the soil and incubated for 60 days. The result shows that BC application immobilized W in soil, and transformed acid extractable fraction and reducible fraction to residual fraction with unstudied mechanism. Meanwhile, BC application increased the shoot height, root length, biomass, and chlorophyll of lettuce compared with control treatment. As compared to control, the accumulation of W in shoot and root was decreased, and the lowest translocation factor (root to shoot) was observed in 5% BC treatment. The results suggested that the main profit of BC to reduce mobilizing of W to proximal water. Besides, the application of BC was effective in W immobilization and reducing uptake to lettuce.