Removal of ammonia nitrogen in wastewater by microwave radiation.

Journal of hazardous materials · 2009 · Benefit · Insufficient evidence

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BenefitInsufficient evidencePaper 6473

Study snapshot

PublicationJournal of hazardous materials · 2009

Study typeengineering

Reported directionBenefit

Evidence ratingInsufficient

Abstract

Ammonia nitrogen contaminated wastewater has posed great threat on the safety of water resources. In this study, a novel process, microwave (MW) radiation, was developed for the removal of ammonia nitrogen from wastewater. The effects of pH, radiation time, aeration and initial ammonia concentration on the removal were investigated. pH and radiation time showed significant influence on the removal of ammonia nitrogen. The largest removal was obtained at pH 11 in 3 min. Initial ammonia concentration and aeration had minute influence. The mechanism of ammonia removal was proposed as the formation of molecular ammonia (NH(3)) and the subsequent evaporation of NH(3) by MW radiation. Compared with conventional heating (CH) mode, MW radiation led to higher ammonia removal. Both thermal and non-thermal effects were responsible for the removal, but the contribution of thermal effect was more significant. In the end, coke-plant wastewater containing high concentration of ammonia nitrogen was treated by MW radiation. With the initial ammonia concentration of 5000 mg/L at pH 11, ammonia was reduced to 350 mg/L at 750 W by 10 min MW radiation. It could be proposed that MW radiation was an effective method for the removal of ammonia nitrogen from wastewater.

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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 typeengineering

Effect directionbenefit

PopulationNot supplied

Sample sizeNot supplied

Exposuremicrowave · 3–10 min (radiation time tested; examples: 3 min, 10 min)

Evidence strengthInsufficientConfidence: 74% · Peer reviewed: yes

Main findings

Microwave radiation was investigated as a process to remove ammonia nitrogen from wastewater; pH and radiation time significantly influenced removal, with the largest removal at pH 11 in 3 min. Compared with conventional heating, microwave radiation produced higher ammonia removal; the authors attribute removal to formation of NH3 and subsequent evaporation, with thermal effects more significant than non-thermal. In coke-plant wastewater (initial ammonia 5000 mg/L at pH 11), ammonia was reduced to 350 mg/L at 750 W after 10 min of microwave radiation.

Outcomes measured

Ammonia nitrogen removal from wastewater
Effect of pH on ammonia removal
Effect of radiation time on ammonia removal
Effect of aeration on ammonia removal
Effect of initial ammonia concentration on ammonia removal
Comparison of microwave radiation vs conventional heating
Treatment performance on coke-plant wastewater (ammonia reduction)

Limitations

Microwave frequency not reported in abstract
No sample size/replication details provided in abstract
Outcome is an engineering/wastewater treatment endpoint rather than a health endpoint

View raw extracted JSON

{
  "study_type": "engineering",
  "exposure": {
    "band": "microwave",
    "source": "wastewater treatment (microwave radiation)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "3–10 min (radiation time tested; examples: 3 min, 10 min)"
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Ammonia nitrogen removal from wastewater",
    "Effect of pH on ammonia removal",
    "Effect of radiation time on ammonia removal",
    "Effect of aeration on ammonia removal",
    "Effect of initial ammonia concentration on ammonia removal",
    "Comparison of microwave radiation vs conventional heating",
    "Treatment performance on coke-plant wastewater (ammonia reduction)"
  ],
  "main_findings": "Microwave radiation was investigated as a process to remove ammonia nitrogen from wastewater; pH and radiation time significantly influenced removal, with the largest removal at pH 11 in 3 min. Compared with conventional heating, microwave radiation produced higher ammonia removal; the authors attribute removal to formation of NH3 and subsequent evaporation, with thermal effects more significant than non-thermal. In coke-plant wastewater (initial ammonia 5000 mg/L at pH 11), ammonia was reduced to 350 mg/L at 750 W after 10 min of microwave radiation.",
  "effect_direction": "benefit",
  "limitations": [
    "Microwave frequency not reported in abstract",
    "No sample size/replication details provided in abstract",
    "Outcome is an engineering/wastewater treatment endpoint rather than a health endpoint"
  ],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "microwave radiation",
    "wastewater",
    "ammonia nitrogen",
    "pH",
    "radiation time",
    "aeration",
    "conventional heating",
    "thermal effects",
    "non-thermal effects",
    "coke-plant wastewater"
  ],
  "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.jhazmat.2008.04.053
PubMed: 18502036

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