Petroleum oily sludge secondary resource
Heterogeneous oil-, water- and solid-bearing residues generated in petroleum handling and processing, with feed-dependent metals and metalloids. This resource context includes the characterized crude-oil tank-bottom sludge from Karoon Oil and Gas Company in Iran studied by Nejad et al. (2020), and the distinct weathering-pit refinery sludge collected in Bahrain in March 2020 studied by Hentati et al. (2022). It is not raw crude oil, produced water, petroleum coke, combustion ash, or oil-sands froth-treatment tailings. Neither constituent criticality nor economic recoverability is assigned to the mixed residue. Lower reported residual metal concentrations in one laboratory treatment do not establish metal extraction, biomass capture, or recovery.
Microbial & Biochemical Mechanisms (1)
Qualified culture-associated residual metal concentration changes
other
Microbial
Associated Organisms:
Stutzerimonas balearica (NCBITaxon:74829)
Nejad2020 Table 3 reports lower residual than initial concentrations during treatment with the live isolate called Pseudomonas balearica Z8 by the authors: nickel 23 to 17 mg/kg, copper 14 to 11 mg/kg and zinc 168 to 148 mg/kg. These are source-reported concentration comparisons in an incompletely specified sampled fraction and mass basis, not measured metal-mass removal or recovery. The proposed biosorption explanation is untested: no separate biomass metal assay, dissolved-metal balance or isolated recovered product is reported. The table alone cannot establish microbial causation or distinguish dilution and sampling/partition changes.
Experimental Context & Analytical Limits:
The Iranian crude-oil tank-bottom feed was a black semisolid; Table 1 reports pH 7.1 and 19% solids. Acclimation used 10 g oily sludge in 100 mL mineral enrichment medium, a 250 mL flask and 5 mL pure-culture nutrient broth at OD600 2. The enrichment recipe itself supplies Fe, Mn and trace Zn, Co, Mo and Cu, so it is not a metal-free input. These acclimation quantities are not a verified dose for every later treatment vessel. One-factor sludge assays explored nitrogen source, 1:1–1:7 sludge/water ratios reported as v/v, and 20–60 degrees C over 80 days. The abstract and Figure 7 caption name NH4Cl for the selected 40-degree-C, 1:7 condition, but the nitrogen and ratio prose instead names ammonium sulfate; the exact recipe underlying Table 3 is therefore unresolved. Table 3 says only before/after treatment under selected conditions, without its own sampling day, residual-phase separation, wet/dry basis, replicate uncertainty, biomass removal procedure or matched metal-control results. The approximately 2% uninoculated-control change concerns total petroleum hydrocarbons, not metals, and does not prove a sterile control. The metal method digests a 2 g sample using HNO3/H2O2, reduces the volume, dilutes to 100 mL and centrifuges the digest at 3000 rpm for 10 minutes. It calls the instrument ICP-MS while naming SPECTRO ARCOS, which the manufacturer describes as ICP-OES; the platform actually used is not resolved. The text's 18–36% metal-removal range excludes Table 3's zinc entry rendered as 11/9%; slash-form decimal tokens are not silently normalized. No structured concentration observations are assigned because analysis dates and sampled-fraction/denominator details are missing. Laboratory treatment of an industrial-origin feed does not establish industrial deployment, a recoverable metal reserve or treatment economics.
The Iranian crude-oil tank-bottom feed was a black semisolid; Table 1 reports pH 7.1 and 19% solids. Acclimation used 10 g oily sludge in 100 mL mineral enrichment medium, a 250 mL flask and 5 mL pure-culture nutrient broth at OD600 2. The enrichment recipe itself supplies Fe, Mn and trace Zn, Co, Mo and Cu, so it is not a metal-free input. These acclimation quantities are not a verified dose for every later treatment vessel. One-factor sludge assays explored nitrogen source, 1:1–1:7 sludge/water ratios reported as v/v, and 20–60 degrees C over 80 days. The abstract and Figure 7 caption name NH4Cl for the selected 40-degree-C, 1:7 condition, but the nitrogen and ratio prose instead names ammonium sulfate; the exact recipe underlying Table 3 is therefore unresolved. Table 3 says only before/after treatment under selected conditions, without its own sampling day, residual-phase separation, wet/dry basis, replicate uncertainty, biomass removal procedure or matched metal-control results. The approximately 2% uninoculated-control change concerns total petroleum hydrocarbons, not metals, and does not prove a sterile control. The metal method digests a 2 g sample using HNO3/H2O2, reduces the volume, dilutes to 100 mL and centrifuges the digest at 3000 rpm for 10 minutes. It calls the instrument ICP-MS while naming SPECTRO ARCOS, which the manufacturer describes as ICP-OES; the platform actually used is not resolved. The text's 18–36% metal-removal range excludes Table 3's zinc entry rendered as 11/9%; slash-form decimal tokens are not silently normalized. No structured concentration observations are assigned because analysis dates and sampled-fraction/denominator details are missing. Laboratory treatment of an industrial-origin feed does not establish industrial deployment, a recoverable metal reserve or treatment economics.
Curated Evidence Points:
Partial
Source:
nejad2020
Methods, Tables 1 and 3 and Figure 7 support the identity of the real tank-bottom feed and the reported before/after concentration comparison associated with culture treatment. Missing phase and mass balances, metal controls, replicate uncertainty and conflicting nitrogen recipes prevent stronger causal, biosorption or extraction claims. Table 2 and the adjoining text also interchange the rhamnolipid assignments for m/z 503 and 529; Figure 6 provides selected ion traces, not a causal test of metal binding. No particular rhamnolipid congener is assigned responsibility here.
Context_only
Source:
ahmadi2017
The complete ESM1 is the earlier 2017 petrochemical-wastewater study, rather than additional oily-sludge metal data. Its isolation, 16S-based identification and phylogeny support the reported Z8 lineage; consortium COD performance cannot be transferred to Z8-specific metal removal from oily sludge.
Context_only
Source:
ncbi_balearica
The current species name and historical synonym justify the species CURIE and label. This mapping is not a strain identifier or proof of the composition and identity of the later experimental stock.
Context_only
Source:
genbank_z8
The deposited partial 16S sequence explicitly bears strain Z8 and the original wastewater study. It corroborates the reported isolate label, without a genome-level identity claim or authentication of the 2020 experimental culture.
Context_only
Source:
spectro_arcos
The manufacturer's optical-emission designation exposes the article's ICP-MS/model inconsistency; it does not resolve the laboratory's actual instrument, calibration or analytical recovery.
Context_only
Source:
hentati2022
The separate Bahrain weathering-pit feed contains nickel, vanadium and other elements in Table S1. AK6 experiments quantify extractable hydrocarbons and community composition, not metal release, capture or isolated recovery. They neither replicate nor repair Nejad2020's residual-metal comparison and must not be treated as metal extraction evidence.
Sources & References
-
nejad2020: Nejad et al. (2020), Remediation of oily sludge wastes using biosurfactant produced by bacterial isolate Pseudomonas balearica strain Z8, Journal of Environmental Health Science and Engineering 18:531–539, DOI 10.1007/s40201-020-00480-1; complete publisher/PMC HTML, methods, Tables 1–3 and Figures 1–7
https://doi.org/10.1007/s40201-020-00480-1 (accessed 2026-10-15) -
ahmadi2017: Ahmadi et al. (2017), A novel salt-tolerant bacterial consortium for biodegradation of saline and recalcitrant petrochemical wastewater, DOI 10.1016/j.jenvman.2017.01.010; complete article supplied as Nejad2020 ESM1, sections 2.1–2.2, 3.2.3 and Figure 2; isolate provenance only, not an oily-sludge metal-recovery experiment
https://doi.org/10.1016/j.jenvman.2017.01.010 (accessed 2026-10-15) -
hentati2022: Hentati et al. (2022), Biotreatment of oily sludge by a bacterial consortium: Effect of bioprocess conditions on biodegradation efficiency and bacterial community structure, Frontiers in Microbiology 13:998076, DOI 10.3389/fmicb.2022.998076; feed characterization and supplementary Table S1; distinct Bahrain feed and hydrocarbon assays
https://doi.org/10.3389/fmicb.2022.998076 (accessed 2026-10-15) -
ncbi_balearica: NCBI Taxonomy 74829, Stutzerimonas balearica, species rank; Pseudomonas balearica is a synonym; current species label does not independently authenticate the experimental stock
https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=74829 (accessed 2026-10-15) -
genbank_z8: NCBI GenBank KX495190.2, Stutzerimonas balearica strain Z8 partial 16S ribosomal RNA gene from petrochemical wastewater in Iran; inspected current sequence version, whose GenBank COMMENT states it replaced KX495190.1 on 2017-02-21; the accession references the Ahmadi2017 isolate-context study
https://www.ncbi.nlm.nih.gov/nuccore/KX495190.2 (accessed 2026-10-15) -
spectro_arcos: SPECTRO manufacturer product description, SPECTRO ARCOS ICP-OES; context for the incompatible ICP-MS/model wording in Nejad2020, not verification of the instrument actually used
https://www.spectro.com/products/icp-oes-aes-spectrometers/arcos-inductively-coupled-plasma (accessed 2026-10-15)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-15T17:14:38Z |
codex /root/round99_resources (GPT-6; Codex) | CREATE | Curated petroleum oily-sludge resource identity and narrowly qualified culture-associated residual metal concentrations from complete primary HTML, figures, supplements and current taxonomy; retained uncertain sampled fractions, conflicting recipes, missing balances and the distinction from hydrocarbon biodegradation and isolated metal recovery. |
2026-10-15T17:29:16Z |
codex /root/round99_resources (GPT-6; Codex) | EDIT | Corrected the GenBank source title and URL to the actually inspected KX495190.2, retaining its stated 2017-02-21 replacement of .1. Addressed review issue 361 without changing the species, strain, material scope or qualified experimental comparison; the earlier CREATE history and source dossier remain preserved. |
Record source: data/records/petroleum-oily-sludge.yaml