Journal of Environmental Engineering

Fine particulate matter is challenging to capture due to its minuscule size, which affects its chargeability. The agglomeration method has been proven to be the most effective pretreatment technology for enhancing the removal of fine particles. This study proposes a novel dust-removal system that integrates turbulence-induced agglomeration into the wet electrostatic precipitator. The results showed that the removal efficiency of fine particles with a negative corona voltage was significantly higher, and removal efficiencies for particles smaller than 10.0 μm exceeded 90%. Furthermore, fine particles carried a larger charge when subjected to negative corona discharge, resulting in more-effective dust retention. The turbulence effect facilitates the removal of fine particles by promoting their agglomeration in turbulent conditions. The removal efficiency can increase significantly with turbulence, and this enhancement effect is more pronounced at higher flow rates. This study provides insight into the comprehensive removal of multiple pollutants from industrial flue gases.

This study presents a groundbreaking composite adsorbent, STB@MOF-808-SH, developed through the innovative amalgamation of thiol-functionalized metal-organic framework material (MOF-808-SH) with sulfur-doped ${\mathrm{C}}_3{\mathrm{N}}_4$ tubular bundles (STB), targeting the effective elimination of toxic mercury [Hg(II)] ions from polluted water. Our investigation explores crucial determinants of the adsorption process, including pH, initial Hg(II) concentration, and the impact of coexisting ions, while revealing the significant enhancement in mercury ion removal efficiency and adsorption capacity due to the synergistic interaction between STB and MOF-808-SH. Remarkably, under optimal conditions at pH 4.0, STB@MOF-808-SH achieves a removal rate of 91.35% and an impressive adsorption capacity of $228.38\mathrm{mg}/\mathrm{g}$. These outcomes suggest that the development of the STB@MOF-808-SH composite adsorbent introduces a novel and efficacious approach to tackling water pollution issues, highlighting its potential as a cost-effective and efficient solution for the remediation of toxic Hg(II) ions in wastewater.

${\mathrm{Bir}\text{-}\mathrm{MnO}}_2$ was synthesized through a hydrothermal method and modified into H-Bir by nitric acid acidification. The mechanism of its action in ozonation was explored by characterization. H-Bir possessed more oxygen vacancies and lower average oxidation state (AOS) than ${\mathrm{Bir}\text{-}\mathrm{MnO}}_2$. The oxygen vacancies and surface hydroxyl groups are the main active sites of this catalyst. Under the reaction conditions of initial $\mathrm{pH}=7$, ozone dosage of $7\mathrm{mg}/\mathrm{L}$, initial pollutant concentration of $10\mathrm{mg}/\mathrm{L}$, and catalyst dosage of $0.5\mathrm{g}/\mathrm{L}$ for $40\min$, the degradation rates of H-Bir catalyzed ozonation of p-nitrobenzoic acid (PNBA) and 4-chlorobenzoic acid (PCBA) reached 82.68% and 85.83%, respectively. Differences in the degradation factors affecting PCBA and PNBA were found in the performance study of H-Bir catalyzed ozonation. The combination of density functional theory (DFT) and catalytic ozonation experiment results revealed the difference between the degradation of PNBA and PCBA in the ${\mathrm{H}\text{-}\mathrm{Bir}/\mathrm{O}}_3$ system. It was deduced that the nitro, chlorine and carboxyl groups were the main reaction sites. Possible degradation pathways for the two pollutants were also proposed.

Petroleum-based drilling cuttings (PBDCs), as hazardous waste, are characterized by high petroleum pollutant contents and complex compositions and must be properly treated. Their treatment by a hammermill thermal desorption system can generate a variety of products, necessitating better delineation of the transformation characteristics of organic matter at the molecular level. In this study, the transformation characteristics of organic matter in the treatment of PBDCs by a hammermill thermal desorption system have been analyzed by positive-ion atmospheric-pressure photo-ionization Fourier-transform ion cyclotron resonance mass spectrometry (+APPI FT-ICR MS). The results showed that the PBDCs contained large amounts of CH, CHO, and CHON compounds and a small amount of CHS compounds. Of these, CH and CHO compounds are easily separated and recovered by the hammermill thermal desorption treatment system. Most of this organic matter is separated directly through physical changes, whereas only 0.32% undergoes chemical reactions. The organic matter in the recovered petroleum and #110 industrial white oil was highly reproducible and similar in terms of saturation and aromaticity. The mineral composition of the PBDCs did not change significantly during treatment by the hammermill thermal desorption system. This research may provide theoretical guidance for the efficient treatment of PBDCs by the hammermill thermal desorption system.

Urban stormwater commonly contains many pollutants. This has threatened the ecological health of receiving waters as well as stormwater reuse safety. In this context, an effective treatment of urban stormwater is essential. This study undertook a feasibility investigation on using membranes to remove heavy metals from urban stormwater. Two of the most commonly used membranes in the field of water treatment, namely flat ceramic membrane and organic flat membrane, were selected. The research outcomes showed both membranes had the potential to treat urban stormwater. In the case of real stormwater in low influent velocity, the removal percentages were 77.48% (Zn), 64.33% (Cu), 98.04% (Pb), 74.45% (Ni), 56.96% (Cr), and 49.81% (Cd) for flat ceramic membranes and 81.76% (Zn), 77.69% (Cu), 98.13% (Pb), 81.49% (Ni), 59.62% (Cr), and 68.55% (Cd) for organic flat membranes. In high influent velocity, they were 78.66%, 67.74%, 97.02%, 60.84%, 49.05%, and 78.06% for flat ceramic membranes and 74.35%, 66.70%, 96.94%, 61.19%, 48.79%, and 88.00% for organic flat membranes. However, the influence of membrane types on treatment performance was secondary to rainfall characteristics and pollutant forms. It was noted that the heavy metal removal percentages had lower variability for events with high rainfall intensity while both membranes indicated a significant preference on treating particulate pollutants by interception mechanisms. The results also highlighted that using membrane technology to treat stormwater might have a relatively low cost due to low membrane fouling. This reduced the cost of replacement and maintenance. These research outcomes provided an effective stormwater treatment approach and can provide improved stormwater quality, ensuring its reuse safety.

Fieldwork was carried out in the western area of Edmonton, Alberta, Canada to assess the ${\mathrm{H}}_2\mathrm{S}$ contribution of a long force main and to investigate the source of ${\mathrm{H}}_2\mathrm{S}$ generation in a complex sewer network. The study sewer trunk has a length of 10 km, a diameter of up to 1.95 m, and flow rate of up to $0.6{\mathrm{m}}^3/\mathrm{s}$. In the upstream, there is a 5.6 km forcemain, and the pump station operation can cause a sudden increase of ${\mathrm{H}}_2\mathrm{S}$ in the sewer air of the discharge manholes to reach 500 ppm. Wastewater samples were collected in 14 manholes in the sewer network and analyzed for sulfide and other relevant parameters. The maximum values of sulfide were $9.7\mathrm{mg}\mathrm{S}/\mathrm{L}$ and pH remained mostly neutral. For predicting the sulfide generation rate, an empirical model was applied with readily biodegradable organic matter. Then the emission of ${\mathrm{H}}_2\mathrm{S}$ in gravity pipes was investigated, and it was found over 90% of ${\mathrm{H}}_2\mathrm{S}$ stayed in the liquid phase when wastewater flowed in gravity sewer pipes. Finally, the mass transfer in a drop structure of 8 m was investigated. The liquid phase ${\mathrm{H}}_2\mathrm{S}$ concentration in the upstream was 2.6 times that of the downstream, and about 62% of the ${\mathrm{H}}_2\mathrm{S}$ was released in this drop structure indicating the significant emission of ${\mathrm{H}}_2\mathrm{S}$ in drop structures.