Thurston County Landfill Closure
Client: Thurston County
Location: Thurston County, Washington
When the 20-acre municipal solid waste landfill stopped receiving waste years earlier than expected, Thurston County needed to quickly make decisions and move forward with closing the facility. The County partnered with MFA to design the interim and final landfill closure utilizing an alternative cover system which saved the County both time and money. MFA’s creative approach used excavated material to construct the preliminary slope grades, accelerate the settlement of underlying refuse, and create a stormwater retention pond to accept runoff from the closed landfill. MFA also provided plans and specifications, assisted with the bid process and provided quality assurance services during construction.
The landfill closure and cap design successfully met the County’s goals to secure necessary permits and approvals within an expedited timeframe. Project highlights include:
- Minimizing costs by regrading the landfill surface with material from excavating the stormwater retention pond.
- Saving the County $500,000 by using the alternative cover system.
- Reaching interim closure within five months with MFA’s design of an enhanced landfill gas collection system.
- Completing the entire project, from start of interim closure to completion of final closure construction, in just over a year.
An otherwise challenging situation was turned into a success through MFA’s creative approach which saved time and money and allowed Thurston County to meet its community’s needs.