In-depth research on percarbonate expediting zero-valent iron corrosion for conditioning anaerobically digested sludge

A total of 25 municipal sewage treatment plants were sampled, 10 of which were resampled, to determine the quantity of phenolics in the sewage, final effluent and the anaerobically digested sludge using capillary GC/MS/DS/techniques. The study noted in decreasing order of frequency in raw sewage: phenol, pentachloro-phenol, dimethyl phenol, 3-methyl, 4-chlorophenol, 2,4,6-trichloro-phenol, 2,4-dichlorophenol, 2-nitrophenol, 2-chlorophenol, 2,4-dinitro-6-methylphenol and 2,4-dinitrophenol. The maximum concentration of phenol in sewage and sludge was 2800 ppb and 4460 respectively, while similar values for pentachlorophenol were 58 and 1200 ppb. Statistically calculated concentration reductions for phenol and dimethyl phenol were generally greater than noted for tri- and pentachlorophenol. Low decreases or increases were noted for monochlorophenol and especially for dichlorophenol as a result of the chloronation of the final effluent.

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Characterization of raw sludge, chemically modified sludge and anaerobically digested sludge in Hong Kong

Water Science & Technology ◽

10.2166/wst.1998.0095 ◽

1998 ◽

Vol 38 (2) ◽

pp. 25-32 ◽

Cited By ~ 2

Author(s):

C. W. Chu ◽

C. S. Poon ◽

R. Y. H. Cheung

Keyword(s):

Hong Kong ◽

Sewage Treatment ◽

Sewage Treatment Plant ◽

Treatment Plant ◽

Chemical Properties ◽

Primary Treatment ◽

Digested Sludge ◽

Total N ◽

Chemically Modified ◽

Anaerobically Digested Sludge

Chemically Enhanced Primary Treatment (CEPT) or Chemically Assisted Primary Sedimentation (CAPS) is being employed at the new sewage work on Stonecutters Island as part of the Strategic Sewage Disposal Scheme (SSDS) in Hong Kong. CAPS involves the use of chemical coagulants (such as lime or ferric chloride) to induce coagulation or flocculation and let these finely-divided particles form large aggregates (floc) so that they can settle out within a reasonable period of time. In this study, five sludge samples collected from different sewage treatment plants in Hong Kong were physically and chemically characterized. They were chemically modified sludge from Stonecutters Island (CAPS) raw sludge from Tai Po and Yuen Long Sewage Treatment Plant (STP) (rTP & rYL) and anaerobically digested sludge from Tai Po and Yuen Long STP (dTP & dYL). It was found that CAPS sludge was better than other 4 sludge samples in terms of settleability and dewaterability. CAPS sludge contained significant higher amounts (p<0.01) of extractable compounds than other sludges (except NO3− for dTP, NH4+ and PO43− for dYL). The concentration of total N and P in CAPS sludge were significantly higher (p<0.01) than other sludges (except dYL). The concentrations of total Cu, Pb, Ni, Cd, Cr and K in the CAPS sludge were also significantly higher (p<0.01) than other sludge samples. Most of the metals (Cr, Pb, Cr and Zn) in CAPS sludge were associated with the organically-bounded phase. It is concluded that there are significant differences in both physical and chemical properties between the chemically modified sludge and biological treated sludges.

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Ultrasound assisted zero valent iron corrosion for peroxymonosulfate activation for Rhodamine-B degradation

Chemosphere ◽

10.1016/j.chemosphere.2019.04.164 ◽

2019 ◽

Vol 228 ◽

pp. 412-417 ◽

Cited By ~ 37

Author(s):

Yixiong Pang ◽

Yang Ruan ◽

Yong Feng ◽

Zenghui Diao ◽

Kaimin Shih ◽

...

Keyword(s):

Rhodamine B ◽

Zero Valent Iron ◽

Iron Corrosion ◽

Ultrasound Assisted

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Bioleaching of toxic metals from anaerobically digested sludge without external chemical addition

Water Research ◽

10.1016/j.watres.2021.117211 ◽

2021 ◽

pp. 117211

Author(s):

Zhiyao Wang ◽

Gaofeng Ni ◽

Jun Xia ◽

Yarong Song ◽

Shihu Hu ◽

...

Keyword(s):

Toxic Metals ◽

Digested Sludge ◽

Anaerobically Digested Sludge

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Carbothermal Synthesis of Ni/Fe Bimetallic Nanoparticles Embedded into Graphitized Carbon for Efficient Removal of Chlorophenol

Nanomaterials ◽

10.3390/nano11061417 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1417

Author(s):

Min Zhuang ◽

Wen Shi ◽

Hui Wang ◽

Liqiang Cui ◽

Guixiang Quan ◽

...

Keyword(s):

Removal Efficiency ◽

Surface Passivation ◽

Bimetallic Nanoparticles ◽

Zero Valent Iron ◽

Molar Ratio ◽

Particle Sizes ◽

Iron Corrosion ◽

Graphitized Carbon ◽

Nanoscale Zero Valent Iron ◽

Iron Nickel

The reactivity of nanoscale zero-valent iron is limited by surface passivation and particle agglomeration. Here, Ni/Fe bimetallic nanoparticles embedded into graphitized carbon (NiFe@GC) were prepared from Ni/Fe bimetallic complex through a carbothermal reduction treatment. The Ni/Fe nanoparticles were uniformly distributed in the GC matrix with controllable particle sizes, and NiFe@GC exhibited a larger specific surface area than unsupported nanoscale zero-valent iron/nickel (FeNi NPs). The XRD results revealed that Ni/Fe bimetallic nanoparticles embedded into graphitized carbon were protected from oxidization. The NiFe@GC performed excellently in 2,4,6-trichlorophenol (TCP) removal from an aqueous solution. The removal efficiency of TCP for NiFe@GC-50 was more than twice that of FeNi nanoparticles, and the removal efficiency of TCP increased from 78.5% to 94.1% when the Ni/Fe molar ratio increased from 0 to 50%. The removal efficiency of TCP by NiFe@GC-50 can maintain 76.8% after 10 days of aging, much higher than that of FeNi NPs (29.6%). The higher performance of NiFe@GC should be ascribed to the significant synergistic effect of the combination of NiFe bimetallic nanoparticles and GC. In the presence of Ni, atomic H* generated by zero-valent iron corrosion can accelerate TCP removal. The GC coated on the surface of Ni/Fe bimetallic nanoparticles can protect them from oxidation and deactivation.

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