Definition of influent in English:



  • Flowing in.

    ‘the influent lines were relocated while waste water was still flowing’
    • ‘The high sludge yields were caused by unexpectedly high and erratic levels of influent solids for which the builders were not responsible.’
    • ‘The reactor system includes a treatment basin having an inlet for continuously receiving an influent stream and an outlet for continuously discharging an effluent stream, and contains a mixed liquor.’
    • ‘In summer, influent waters are commonly warm and enter the uppermost waters, but cooler rainwater falling at night may sink to the level of the thermocline before moving out into the basin.’
    • ‘Therefore, adjustments to the dosing system must be made when influent flows change substantially.’
    • ‘The influent pump shaft acts as a lift station delivering raw sewage from a newly constructed 9.5-mile-long 18-foot diameter rock tunnel.’
    • ‘He was a fantastic racehorse and like a lot of Danehill's sons can become an influent sire.’
    • ‘Municipal water treatment plants must charge customers for the increased chemicals and electricity necessary for water treatment when influent raw water has high turbidity levels.’
    • ‘The influent waters carry not only solute loads, but also sediments both in suspension and along the bed of the streams.’
    • ‘In case of the river Ganges, it is effluent in south-west while influent in the north of Calcutta.’
    • ‘Use at least a 4-inch diameter sewer line (also known as influent line or distribution pipe) from the house to the lagoon.’
    • ‘The influent solution was sparged continuously with N2 gas to maintain anoxic conditions for the bacteria and to prevent aerobic oxidation of the materials in the wastewater.’


  • 1A stream, especially a tributary, which flows into another stream or lake.

    • ‘Each system is designed to handle a certain volume of water per day, but the system is also tailored for the qualities of the specific influent.’
    • ‘In an extensive survey of U.S. wastewater treatment plants, Schulz has found perfluorinated compounds in influents and effluents.’
    • ‘The method involves the steps of continuously flowing an influent into a treatment basin and continuously flowing an effluent out of the treatment basin into a clarifier.’
    • ‘Good examples of influent streams include the Nile, and the Colorado River in the southwestern United States.’
    • ‘This proves that the presence of ASP effluent in the Knostrop influent is not detrimental to settlement and that the Knostrop influent is capable of good settlement with proper operation.’
    brook, rivulet, rill, runnel, streamlet, freshet
    View synonyms
    1. 1.1Ecology A nondominant organism that has a major effect on the balance of a plant or animal community.
      • ‘fnu typically ranges from 0.00-0.04 for raw influents and from 0.00-0.05 for settled influents.’
      • ‘In Chile, a pending study by Claudio Miranda, of the Laboratory of Aquatic Pathology, found antibiotic-resistant bacteria in fish farm effluent that was ‘significantly higher ‘than the influent, the feed or any other element.’’


Late Middle English (as an adjective): from Latin influent- ‘flowing in’, from influere (see influence). The noun is recorded from the mid 19th century.