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Application of microwave radiation to biofilm heating during wastewater treatment in trickling filters.

Bioresource technology · 2013 · Mixed · Low evidence

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MixedLow evidencePaper 6552

Microwave heating of trickling filters (continuous or intermittent) was compared with convective heating at 20, 25, 35, and 40 C. No effect of microwave heating on organic removal was observed. Continuous microwave exposure (with organic compounds in the inf…

Study snapshot

PublicationBioresource technology · 2013
Study typeother
Reported directionMixed
Evidence ratingLow

Abstract

The purpose of this study was to demonstrate the potential for improving wastewater treatment by the application of microwave radiation (MW) compared to convective heating (CH) of trickling filters. Microwaves were delivered to the biofilm in a continuous and intermittent way to obtain temperatures of 20, 25, 35 and 40 °C. Although there was no effect of MW on organic removal, the observed yield coefficient was lower during the continuous MW supply compared to the periodic dosage and CH. The presence of organic compounds in the influent and continuous biofilm exposure to MW resulted in ca. 10% higher efficiency and ca. 20% higher rate of nitrification compared to intermittent MW dosage and CH. Independent of the method of reactor heating, the absence of organic carbon in the influent induced a significant increase in ammonium oxidation efficiency at 20-35 °C. Despite the aerobic conditions in trickling filters, nitrogen loss was observed.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeother
Effect directionmixed
PopulationNot supplied
Sample sizeNot supplied
Exposuremicrowave · continuous and intermittent application
Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Microwave heating of trickling filters (continuous or intermittent) was compared with convective heating at 20, 25, 35, and 40 C. No effect of microwave heating on organic removal was observed. Continuous microwave exposure (with organic compounds in the influent) was associated with ~10% higher nitrification efficiency and ~20% higher nitrification rate compared with intermittent microwave dosing and convective heating, and a lower observed yield coefficient than periodic dosing and convective heating.

Outcomes measured

  • organic removal
  • yield coefficient
  • nitrification efficiency
  • nitrification rate
  • ammonium oxidation efficiency
  • nitrogen loss

Limitations

  • Microwave frequency and dosimetry (e.g., SAR) were not reported in the abstract.
  • Sample size and replication were not reported in the abstract.
  • Findings are in an engineered wastewater treatment system; no human/animal health outcomes were assessed.
View raw extracted JSON
{
  "study_type": "other",
  "exposure": {
    "band": "microwave",
    "source": "wastewater treatment reactor (trickling filters)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "continuous and intermittent application"
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "organic removal",
    "yield coefficient",
    "nitrification efficiency",
    "nitrification rate",
    "ammonium oxidation efficiency",
    "nitrogen loss"
  ],
  "main_findings": "Microwave heating of trickling filters (continuous or intermittent) was compared with convective heating at 20, 25, 35, and 40 \u0000C. No effect of microwave heating on organic removal was observed. Continuous microwave exposure (with organic compounds in the influent) was associated with ~10% higher nitrification efficiency and ~20% higher nitrification rate compared with intermittent microwave dosing and convective heating, and a lower observed yield coefficient than periodic dosing and convective heating.",
  "effect_direction": "mixed",
  "limitations": [
    "Microwave frequency and dosimetry (e.g., SAR) were not reported in the abstract.",
    "Sample size and replication were not reported in the abstract.",
    "Findings are in an engineered wastewater treatment system; no human/animal health outcomes were assessed."
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "microwave radiation",
    "biofilm",
    "wastewater treatment",
    "trickling filters",
    "convective heating",
    "nitrification",
    "ammonium oxidation",
    "yield coefficient"
  ],
  "suggested_hubs": []
}
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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1016/j.biortech.2012.09.102
PubMed: 23131645

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