Waste-treatment engineers defined

The definitive estimates are prepared after the project has been totally defined, including offsites, waste treatment, site conditions, equipment arrangements, etc. This stage of definition requires the involvement of an engineering contractor to complete the so-called basic engineering referred to in Chapter 12. 

On a timescale measured since mankind first deposited waste in specifle locations (landfill), most sites have operated on the dilute and attenuate philost y. In the relatively recent past, this principle has been supported by studies in the mid 1970 s (DoE, 1978) which showed attenuation of leachate as it moved through various unsaturated strata. These studies also showed that the attenuation processes (defined to include dilution) could be used to effectively treat landfill leachate as it migrated from the site. The advantages of the dilute and attenuate landfill are that there is no requirement for expensive landfill lining/engineering, and as liquids formed within the site migrate from the base, there is no requirement for leachate collection and treatment facilities. These "advantages necessarily have pollution implications. 

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