Naches - WWTP Improvements - Phase 1

The Naches Wastewater Treatment Plant (WWTP) began accepting wastewater from neighboring Allan Bros., Inc., a fruit packing plant, in February 2019. This additional wastewater, as well as Town population growth had increased operation of the nearly 20-year-old belt filter press by 50 percent. An engineering report was prepared by HLA defining the required improvements and submitted to the Department of Ecology for approval.

Improvements enhanced sludge handling and biosolid treatment and included a sludge holding tank and new dewatering equipment. By storing sludge in the new holding tank rather than clarifiers, sludge is better mixed providing consistent feed to the dewatering equipment improving overall performance and drier sludge. New dewatering equipment replaced the aging belt filter press increasing capacity to match other treatment process components proposed for Phase 2 (separate project). A second headworks screen was added in Phase 1 to provide redundancy and quality biosolids.

HLA services included funding administration, design plans and specifications, bidding services, construction observation and administration, and project close-out. 

Sources of Project Funding:

Total Project Cost: 


HLA Engineering and Land Surveying

2803 River Road
Yakima, WA 98902

(509) 966-7000
Contact Us