Differentiate primary from secondary suewage treatmen​

Primary Wastewater TreatmentSecondary Wastewater Treatment

In this method, the waste is processed through a physical procedure with equipment and filtration.The wastewater is purified through biological processes using microorganisms

the transfer of heat by electromagnetic radiation is called thermal radiation . it is usually carried out by electromagnetic waves in an energy range just below the visible spectrum, which is the infrared range.

so the answer would be radiation.

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