Superior removal of humic acid from aqueous stream using novel calf bones charcoal nanoadsorbent in a reversible process.

While the potable water disinfection regimen has significantly reduced waterborne diseases, development of disinfection byproducts (DBP) during this process has brought a global threat to the environment and human health. The most notorious water pollutant, humic acid (HA), transforms into carcinogenic byproducts during the disinfection process (chlorination) of water treatment. HA removal methods are neither economic nor widely available. This study addresses the most urgent global issue of HA removal by developing an innovative and self-regenerative process based on a low-cost and self-regenerative calf bone char (CBC) that removed 92.1-100% of HA. CBC-based HA removal has not been described yet. The developed CBC, as a super adsorbent of HA, was initially characterized by a scanning electron microscope. Various parameters of adsorption/desorption and self-regeneration of CBC adsorbent were experimentally determined. Results show that prepared CBC with a 112 m2/g surface area exhibited adsorption of 38.08 mg/g (HA = 20 mg/L, pH = 4.0) which is several folds higher than the typical amount of HA present in water. The 30 m reaction time was enough to remove HA which is the shorter HA time in comparison to other similar studies. The increase of HA from 0.5 to 5 g/L, raises % HA removal (36.7-99.8%) while a pH decrease (10-4) increases adsorption (12.3-98.3%). The adsorption data fitted well with the pseudo-second-order model and the Langmuir isotherm which demonstrate that adsorption takes place by a monolayer formation. Thermodynamic constants supported the endothermic, spontaneous and reversible nature of adsorption which can attain 100% HA removal. 100% regeneration of exhausted CBC by NaOH further supports the sustainability of the process. CBC as a new adsorbent material thus provides an economical and sustainable water pre-treatment procedure. The present study provides technical guidance for building a cost-effective and scalable process capable of providing clean water.

Bioremediation of micropollutants using living and non-living algae - Current perspectives and challenges.

The emergence and continual accumulation of industrial micropollutants such as dyes, heavy metals, organic matters, and pharmaceutical active compounds (PhACs) in the ecosystem pose an alarming hazard to human health and the general wellbeing of global flora and fauna. To offer eco-friendly solutions, living and non-living algae have lately been identified and broadly practiced as promising agents in the bioremediation of micropollutants. The approach is promoted by recent findings seeing better removal performance, higher efficiency, surface area, and binding affinity of algae in various remediation events compared to bacteria and fungi. To give a proper and significant insight into this technology, this paper comprehensively reviews its current applications, removal mechanisms, comparative efficacies, as well as future outlooks and recommendations. In conducting the review, the secondary data of micropollutants removal have been gathered from numerous sources, from which their removal performances are analyzed and presented in terms of strengths, weaknesses, opportunities, and threats (SWOT), to specifically examine their suitability for selected micropollutants remediation. Based on kinetic, isotherm, thermodynamic, and SWOT analysis, non-living algae are generally more suitable for dyes and heavy metals removal, meanwhile living algae are appropriate for removal of organic matters and PhACs. Moreover, parametric effects on micropollutants removal are evaluated, highlighting that pH is critical for biodegradation activity. For selective pollutants, living and non-living algae show recommendable prospects as agents for the efficient cleaning of industrial wastewaters while awaiting further supporting discoveries in encouraging technology assurance and extensive applications.

Enhancement of nitrification efficiency during sludge bulking by magnetic field under long sludge retention time.

The aim of the present study is to investigate the potential of magnetic field application as an alternative approach for controlling sludge bulking due to long sludge retention time (SRT) while enhancing nitrification efficiency upon the occurrence. Two sequencing batch reactors, reactor A (SBRA, magnetic field intensity 88.0 mT) and reactor B (SBRB, control) were operated under long SRT to induce the growth of filamentous microorganisms. The effect of magnetic field on nitrification, viz. ammonia-nitrogen (NH4-N) and nitrite removal, as well as biomass properties were studied under the sludge bulking condition. Results indicated that nitrification efficiency of SBRA was consistently higher with 90% NH4-N removal and 74-81% nitrite removal, which could be credited to the enhanced biomass properties of activated sludge due to the induced magnetic field. Metabolism activity and biodegradability of aerobic bacteria were also enhanced through the application of magnetic field, even under long SRT condition. This was evidenced by the average oxygen uptake rate (OUR) in SBRA that was higher with 11.7 ± 1.2 mg/L·h compared to SBRB with 9.5 ± 0.4 mg/L·h. Occurrence of filamentous sludge bulking was likewise minimized.