Transportation will not be cost effective. The site can be filled up with top soil and then saplings can be planted for beautification. A new site should be developed as dumping area for hazardous waste.
First of all, Thank you Prof Bhattacharya for your answer. If the transportation is necessary (for example; expanding city borders). Could the stakeholders build on this site or not? Is there a specific period after transportation to build (for example; I can build a light structure 30 years after landfill transportation).
It is better to develop alternate landfill as transportation cost will be more. Alternatively use this site for developing a garden and build other infrastructure around its vicinity.
in your case when a landfill site is become closer to the urban area and the land value increase you can search for landfill post closer (for instance to use the landfill for PV solar panel, or use it as recreational area after proper landscaping. However, there is a new technologies to benefit from the land by developing low rise building (up to 2 floors). such seismic technology and land rehabilitation is developed by Infra tech company.
Examples of building constructions on closed landfills include the sports grounds built for the 1996 Olympic Games in South Korea, a supermarket in the USA, and the soon-to-be- built solid waste transfer station on the Jinkou landfill in Wuhan City, China (Yanget al.,2005).
source: Influence of leachate pollution on mechanical properties of compacted clay: A case study on behaviors and mechanisms, 2013, Eng. Geolgy