activated sludge Sludge that has been aerated and subjected to bacterial action; used to speed breakdown of organism matter in raw sewage during secondary waste treatment
active participation The involvement, either by an individual or a group of individuals, in their own governance or other activities, with the purpose of exerting influence
working population engaged in agriculture The number of a particular region or nation's working population gainfully employed or otherwise occupied with the production of crops, livestock or poultry
