Social Perspectives on the Effective Management of Wastewater

The chapter discusses how adopting a holistic methodology that acknowledges sociological factors, including community participation, public involvement, social perception, attitudes, gender roles and public acceptance, would lead to improvements in wastewater management practice. It highlights the social dimension as a tool, a lens through which wastewater management and reuse can take on new dimensions. In this way, this chapter aims to shift the focus from perceiving wastewater as a nuisance that needs disposal, toward a resource not to be wasted, which can contribute to food security, human and environmental health, access to energy as well as water security

Development and application of polymeric materials for heavy metal ions recovery from industrial and mining wastewaters

M.Sc., Faculty of Science, University of the Witwatersrand, 2011Contamination of water bodies by heavy metals and metalloids is an established problem and several studies have been conducted to deal with it. South Africa is amongst those countries whose water systems are most affected as a result of intensive mining activities. This research was dedicated to the development of insoluble chelating polymers for use as adsorbents to abstract heavy metal ions from mining and industrial wastewater. Branched polyethylenimine (PEI), well known for its metal chelating potential, was cross linked by epichlorohydrin in order to convert it into a water-insoluble form. The water-insoluble property gives the advantage of being used in situ and a possibility of regeneration and re-use, making it a more feasible and cost-effective method. Its surface was also modified for selective removal of specifically-targeted heavy metal and metalloid ions. The binding affinity of the synthesized materials to heavy metal and metalloid ions has been determined as well as their ability to be regenerated for reuse. These processes demonstrated that cross-linked polyethylenimine (CPEI) exhibited good complexation ability with high affinity to Cr and some divalent metal ions such as Fe, Zn, and Ni. On the other hand, it showed very poor ability to bind oxo-anions such as SeO32- and AsO2- which has been attributed to the unavailability of suitable functional groups to interact with these ions. The observed order of complexation was: Cr > Zn> Fe >> Ni > Mn > Pb >> As > U > Se. The phosphonated polyethylenimine (PCPEI) showed high selectivity for As, Mn and uranyl ions. The observed order of removal was: U > Mn> Ni > Zn > As >> Cr > Pb > Fe >> Hg > Se; whereas the suffocated polyethylenimine (SCPEI) exhibited high affinity to Se, and Hg. The observed order of adsorption was: Hg > Se >> U > Zn >Pb > Ni >> As > Cr > Fe. v The adsorption behaviour of these polymeric materials involved more than one mechanism such as complexation, normal surface charge exchange, and anion replacement and all these mechanisms are governed by the functional groups. The nitrogen atom on the chelating group (-NH) in the cross-linked polyethylenimine; the phosphorus atom on the chelating group (-PO3H2) in phosphonated cross-linked polyethylenimine; and sulphur atom on the chelating group (-SO3H) in suffocated cross-linked polyethylenimine act as Lewis bases and donate electrons to metal cations which are considered Lewis acids. The existence of the chelating groups in SCPEI and PCPEI facilitate the removal of oxo-anions through anion replacement since they exist as bases in solution and hence cannot be electron acceptors. Thus, the expected mechanism is the normal anion replacement. This mechanism can explain the high removal of Se by SCPEI since Se has similar chemical behaviour as sulphur and are in the same group in the periodic table. As such they can easily replace each other. Sulphur is released from the polymer into the solution by replacing the selenium ions in the polymer. Similar behaviour occurs between phosphorus in PCPEI and arsenic ions as As and P belong to the same group in the periodic table and hence have similarities in their chemical behaviour. The Langmuir and Freundlich isotherm models were used to interpret the adsorption nature of the metal ions onto synthesized polymers. The Freundlich isotherm was found to best fit and describe the experimental data describing the adsorption process of metal and metalloid ions onto the synthesized polymeric materials The kinetic rates were modelled using the pseudo first-order equation and pseudo second-order equation. The pseudo second-order equation was found to explain the adsorption kinetics most effectively implying chemisorption. vi The thermodynamic study of the adsorption of metals and metalloids by the synthesized CPEI, PCPEI and SCPEI resulted in high activation energies > 41 KJ mol-1 which confirm chemisorption as a mechanism of interaction between adsorbate and adsorbent. So far, the developed polymeric materials showed good results and have potential to be applied successfully for remediation of heavy metal-polluted waters, and they have potential for use in filter systems for household use in communities that use borehole water impacted by mining and industrial waste waters. The desorbed metals can be of use to metal processing industries

Why Microplastics Are Exceptional Contaminants?

Due to the heterogeneous nature of the physiochemical properties of microplastics (MPs), their behaviour in the environment is quite complex compared to other contaminants. The variety of polymers, wide range of sizes, variable shapes and numerous colours influence their mobility, transport and distribution in the different environmental compartments. For example, different shapes and sizes are distributed differently, which influence their bioavailability and ecological impacts. The uptake of MPs by aquatic biota also depends, among others, on their characteristics. This book chapter aims to discuss the ecological and toxicological impacts of MPs in relation to their physical and chemical properties. The chapter starts with a brief introduction explaining the uniqueness of MPs as emerging contaminants and a driver of environmental change. The following two sections then provide deeper insights into their ecological impact at all levels of the ecosystem and highlight the complexity associated with their toxicological effects. Finally, the last section provides more discussion about their properties in the context of their environmental behaviour, fate, bioavailability and toxicity

Constructional Design for Decontamination of Sputum Specimens for Tuberculosis Culture

This paper provides a proposal model for a medical device that can prepare samples for the purpose of  tuberculosis diagnosis using sputum specimens. Conventional methods contain hazards because of the seriousness of the disease and  persons infection probability in the laboratory as well as the time spended to prepare each sample individually. The proposed model has a robot arm operates in a completely closed environment  to prepare all samples at once, which reduces the total time of the process. All operations controlled by the Programmable Logic Controller (PLC).

Effect of Halogen Ions on The Corrosion of Brass In Na2SO4 Solution

This research involves study effect of halogen ions presence in 0.2M sodiumsulphate on the corrosion of brass at room temperature (30oC). Three concentration ofhalogen ions (Fˉ, Clˉ, Brˉ, and Iˉ) were used 0.1, 0.2, and 0.3 M. The different incorrosion parameters before and after added the halogen ions interpreted anddiscussed which involves corrosion potentials (Ecorr), corrosion current densities(icorr), and Tafel slops (bc & ba) in addition to discuss the polarization curves.Polarization resistances (Rp) and the change in free energy (ΔG) werecalculated and interpreted, in addition to calculate the rate of corrosion (Rmpy).The results of this work indicates that the presence of halogen ions inexperimental solution increases the rate of corrosion, and the effect of halogen ionsfollows the sequence to increase the corrosion Iˉ > Clˉ > Fˉ > Brˉ

Clinical and Biochemical Assessment of Lycopene Gel Combined With Nanohydroxyapatite Graft in Treatment of Grade II Furcation Defects: A Randomized Controlled Clinical Study

Background: This study aimed to evaluate the effects of lycopene gel, as a natural antioxidant, mixed with a nanohydroxyapatite graft (NHG) covered by an occlusive resorbable collagen membrane (CM) in the surgical treatment of grade II furcation defects and on the gingival crevicular fluid (GCF) levels of 8-hydroxydeoxyguanosine (8-OHdG), as a marker of oxidative injury. Methods: In this randomized controlled clinical study a total of 24 patients with grade II furcation defects were randomly assigned into three equal groups. Furcation defects in group I were managed with lycopene gel mixed with NHG and CM, group II with NHG and CM, and group III with open flap debridement only. Site-specific changes in clinical parameters including probing depth (PD), vertical clinical attachment level (VCAL), horizontal clinical attachment level (HCAL), radiographic maximum vertical depth (MAX V), and maximum horizontal depth (MAX H) were measured at baseline and six months postoperatively. Gingival crevicular fluid levels of 8-OHdG were analyzed using enzyme-linked immunosorbent assay (ELISA) at baseline, one week, and three months. Results: Surgical management of grade II furcation defects resulted in a significant reduction in PD and 8-OHdG levels and a gain in CAL, MAX V, and MAX H in all groups. The differences between lycopene treated sites compared to NHG and CM alone were not significant at six months but demonstrated significantly superior clinical parameters compared to open flap debridement alone. Conclusion: Lycopene does not confer a benefit when combined with NHG in the surgical treatment of grade II furcation defects

Microplastic abundance and sources in surface water samples of the Vaal River, South Africa

DATA AVAILABILITY : Data are available upon request.Microplastics (MPs) have emerged as a global environmental concern due to their persistent nature. In South Africa, microplastic research has primarily focused on marine systems. However, recent years have seen a shift in focus to studying MPs in South African freshwaters. In this study, MPs with a minimum size of 0.055 mm in surface water of the Vaal River, South Africa, were reported. MPs were 100% prevalent, with a mean numerical abundance of 0.68 ± 0.64 particles/m3. Small-sized MPs of < 1 mm accounted for the largest proportion. MPs were chemically identified as high-density polyethylene, low-density polyethylene, and polypropylene according to their Raman spectra. The prevalence of fragments (41.6%) and fibers (38.5%) over pellets (8.1%) indicates that microplastics are from secondary sources. The prevalence of polyethylene and polypropylene is consistent with microplastics being from secondary sources. These polymers are commonly used in single-use plastics, packing bags, textiles, and containers. These characteristics are of great concern due to their implications on the bioavailability and toxicological impacts of MPs. Consequently, these properties may pose more hazards to aquatic biota inhabiting the Vaal River.The Royal Society, UK, and funded by Government’s Grand Challenges Research Fund (GCRF). Open access funding provided by University of the Witwatersrand.http://link.springer.com/journal/128hj2024ChemistrySDG-06:Clean water and sanitatio

Controlling of Mycobacterium by Natural Degradant-Combination Models for Sequestering Mycolic Acids in Karish Cheese

Degradation of the mycobacterial complex containing mycolic acids (MAs) by natural bioactive compounds is essential for producing safe and value-added foods with therapeutic activities. This study aimed to determine the degradation efficiency of natural organic acid extracts (i.e., citric, malic, tartaric, and lactic), quadri-mix extract from fruits and probiotics (i.e., lemon, apple, grape, and cell-free supernatant of Lactobacillus acidophilus), and synthetic pure organic acids (i.e., citric, malic, tartaric, and lactic), against MA in vitro in phosphate buffer solution (PBS) and Karish cheese models. The degradation effect was evaluated both individually and in combinations at different concentrations of degradants (1, 1.5, and 2%) and at various time intervals (0, 6, 12, 24, and 48 h). The results show that MA degradation percentage recorded its highest value at 2% of mixed fruit extract quadri-mix with L. acidophilus and reached 99.2% after 48 h both in PBS and Karish cheese, unlike other treatments (i.e., citric + malic + tartaric + lactic), individual acids, and sole extracts at all concentrations. Conversely, organic acid quadri-mix revealed the greatest MA degradation% of 95.9, 96.8, and 97.3% at 1, 1.5, and 2%, respectively, after 48 h. Citric acid was more effective in MA degradation than other acids. The fruit extract quadri-mix combined with L. acidophilus-fortified Karish cheese showed the highest sensorial characteristics; hence, it can be considered a novel food-grade degradant for MA and could be a promising biocontrol candidate against Mycobacterium tuberculosis (Mtb) in food matrices