Gumilar et al. 2022 - Nickel and molybdenum additions in POME ethanol treatment

Gumilar and colleagues tested whether nickel and molybdenum additions changed ethanol formation during anaerobic treatment of palm oil mill effluent. This is in-scope supply-chain wastewater-treatment and trace-metal-addition context: it reports POME metal concentrations and metal dosing in a treatment process, but it is not palm-oil occurrence evidence and it does not report heavy-metal removal.

Key numbers

Table 2 reports the starting palm oil mill effluent characteristics. All units are mg/L except pH:

Table 1 defines the nine reactor conditions:

The abstract reports that reactor E, with Mo 3 mg/L and Ni 0.25 mg/L, produced the highest ethanol concentration at 578.44 mgCOD/L. The highest COD removal occurred in reactor D, with Mo 1 mg/L and Ni 0.25 mg/L, at 23.4%.

Table 6 reports anaerobic products after treatment:

The authors report that the ANOVA significance value for ethanol production was 0.000, interpreted as a significant difference among reactor conditions. They state that the highest degree of ethanofication was 0.031 in reactor E, while other reactors ranged from 0.017 to 0.028. Degree of acidification ranged from 0.394 to 0.450, with the smallest value in the control reactor.

Methods (brief)

The study used laboratory-scale anaerobic batch reactors with 5 L working volume. Palm oil mill effluent was collected from PT Condong Garut, Indonesia. Biomass was sludge of POME mixed with cow rumen at 50:50 (v/v) and acclimated to the wastewater. Reactors were flushed with nitrogen at 1 L/min for the first 24 h and then operated with internal biogas circulation until 72 h at 25 +/- 2 degrees C. Initial pH was adjusted to 6.5-7.0, and reactors were filled with POME and biomass at 4:1 (v/v). Nickel was added as NiSO4.6H2O and molybdenum as (NH4)6Mo7O24.4H2O. Soluble COD, pH, and VSS followed Standard Methods; volatile fatty acids were measured by HPLC; ethanol was measured by GC.

Implications

Certification: Do not use these values as palm oil or food occurrence. The measured matrix is palm oil mill effluent and anaerobic treatment reactors.

Courses: Useful supply-chain-treatment context because it gives a quantitative example of trace metals intentionally added to POME treatment to shift anaerobic product formation.

App: Context only. The source can inform due-diligence narratives around palm-oil-mill wastewater handling and trace-metal additions, not consumer product scoring.

Wiki pages this source may touch

• irrigation-and-soil-amendments
• source-attribution-environmental-burden-apportionment
• nickel
• molybdenum
• copper
• zinc
• iron
• manganese

Verification notes

Recovered from skip:not-food-occurrence under the 2026-06-10 inclusion-by-default rule. The old skip treated the paper as out of scope because it was not food occurrence. On reading, it is in-scope as supply-chain wastewater-treatment context with measured POME trace-metal values and intentional Ni/Mo additions.

Numbers were checked against the abstract, Materials and Methods, Tables 1, 2, and 6, the ANOVA and product-formation sections, and the conclusion in the extracted PDF. The source reports no finished palm-oil values, no edible-crop values, and no heavy-metal removal percentages. Products and ingredients are intentionally empty. Decimal commas in the source’s Table 2 values are preserved.

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.