A by-product of sewage treatment is usually a semi-solid waste or slurry, called sewage sludge, that has to undergo further treatment before being suitable for disposal or land application.
Life expectancy is defined statistically as the average number of years remaining for an individual or a group of people at a given age.Longevity refers to the characteristics of the relatively long life span of some members of a population.athematically, life expectancy is the mean number of years of life remaining at a given age, assuming constant mortality rates. It is denoted by, which means the average number of subsequent years of life for someone now aged, according to a particular mortality experience.
DEFINITION of 'Life Expectancy'. 1. The age until which a person is expected to live. 2. The remaining number of years an individual is expected to live, based on IRS issued life expectancy tables.The life expectancy, for required minimum distribution (RMD) calculation purposes, is determined by the current age of the individual.Next Up.he remaining number of years an individual is expected to live, based on IRS issued life expectancy tables. The life expectancy, for required minimum distribution (RMD) calculation purposes, is determined by the current age of the individual.