Assessing the viability of pre-industrial sediment prior to remediation using primary producer (Zostera marina and Spartina alterniflora) growth and survival

Boat Harbour (BH), Nova Scotia, has served as a polishing pond for treated pulp and paper effluent since 1967. In 2020, the effluent flow ceased, and the site will be remediated. The focus of the remediation is the removal of a layer of contaminated sediment, shown to contain high levels of metals and dioxins and furans. Our primary objective was to test whether the underlying pre-industrial sediment could support growth and survival of estuarine plants. A large-diameter (15 cm) corer was used to extract cores from underneath the contaminated layer. These cores were inserted into a reference estuary, along with cores of reference estuarine sediment. Four 3 X 3 subtidal plots were used to test transplants of the estuarine plant Z. marina, and five 1 X 9 marsh edge plots were used to test S. alterniflora. No significant differences in plant growth or survival were observed between BH and reference sediment after 2 months. Post-experiment analysis of contaminants (metals and PCDD/F’s) in both types of sediment and plant tissues showed similarly low levels of contaminants.

Simultaneous Decolorization and Biohydrogen Production from Xylose by Klebsiella oxytoca GS-4-08 in the Presence of Azo Dyes with Sulfonate and Carboxyl Groups

ABSTRACT Biohydrogen production from the pulp and paper effluent containing rich lignocellulosic material could be achieved by the fermentation process. Xylose, an important hemicellulose hydrolysis product, is used less efficiently as a substrate for biohydrogen production. Moreover, azo dyes are usually added to fabricate anticounterfeiting paper, which further increases the complexity of wastewater. This study reports that xylose could serve as the sole carbon source for a pure culture of Klebsiella oxytoca GS-4-08 to achieve simultaneous decolorization and biohydrogen production. With 2 g liter−1 of xylose as the substrate, a maximum xylose utilization rate (URxyl) and a hydrogen molar yield (HMY) of 93.99% and 0.259 mol of H2 mol of xylose−1, respectively, were obtained. Biohydrogen kinetics and electron equivalent (e − equiv) balance calculations indicated that methyl red (MR) penetrates and intracellularly inhibits both the pentose phosphate pathway and pyruvate fermentation pathway, while methyl orange (MO) acted independently of the glycolysis and biohydrogen pathway. The data demonstrate that biohydrogen pathways in the presence of azo dyes with sulfonate and carboxyl groups were different, but the azo dyes could be completely reduced during the biohydrogen production period in the presence of MO or MR. The feasibility of hydrogen production from industrial pulp and paper effluent by the strain if the xylose is sufficient was also proved and was not affected by toxic substances which usually exist in such wastewater, except for chlorophenol. This study offers a promising energy-recycling strategy for treating pulp and paper wastewaters, especially for those containing azo dyes. IMPORTANCE The pulp and paper industry is a major industry in many developing countries, and the global market of pulp and paper wastewater treatment is expected to increase by 60% between 2012 and 2020. Such wastewater contains large amounts of refractory contaminants, such as lignin, whose reclamation is considered economically crucial and environmentally friendly. Furthermore, azo dyes are usually added in order to fabricate anticounterfeiting paper, which further increases the complexity of the pulp and paper wastewater. This work may offer a better understanding of biohydrogen production from xylose in the presence of azo dyes and provide a promising energy-recycling method for treating pulp and paper wastewater, especially for those containing azo dyes.

Tertiary Treatment of Paper Industries Effluent with Advanced Electrochemical Oxidation Process in the Presence of Modified Bentonite Powdery Electrodes

Tertiary treatment wascarried out to treat pulp and paper effluent from secondary treatment processby a three-dimensional electrode system equipped with modifiedbentonites as powdery electrode. The cetyl trimethylammonium bromide modified bentonite (CTAB-bent) and hydroxy-aluminum pillaredorganic bentonite (OH-Al-CTAB-bent) were synthesized and characterized by XRDand FTIR spectroscopy analysis.The impacts such as the dosage of particle electrode, electrolysis times,current density were on the COD removal efficiency and decolorization effect ofeffluent were also investigated. The results showed that the experimentscarried out by three-dimensional electrode system with OH-Al-CTAB-bent weresufficient for the COD and color removal efficiency. A current density of 30mA/cm2, electrolysis time of 40min, and the particle electrodedosage of 1.6g/L were selected as an optimum conditions that allows fast andlow cost treatment. The effluent can achieve the discharge standard of waterpollutants for pulp and paper industry (GB3544-2008) after electrolysis.