Successful Long Term Biosolids Planning: Culmination of a Decade Long Biosolids Master Plan

摘要

The Elledge Wastewater Treatment Plant (WWTP) Centralized Biosolids Drying Facility is theculmination of the decade long implementation of a comprehensive biosolids managementmaster plan conducted by the City of Winston-Salem in the early 1990’s. The master planprovided the roadmap for the biosolids treatment and disposal systems for two wastewatertreatment plants, Elledge WWTP and Muddy Creek WWTP, which at the time were dedicated toa liquid land application program. The master plan recommended a phased approach toimplementation in which they would first migrate to a Class B cake application program throughdewatering improvements at the two plants and then ultimately a Class A program. This allowedthe cost of the overall transition to be phased over time as well as for technological advances inClass A systems to develop and for the regulatory framework for biosolids disposal in NorthCarolina to establish itself. The Elledge WWTP Centralized Biosolids Facility is the largestthermal drying system in the Carolinas at 36 dry metric tonnes per day (dmtpd) (40 dtpd) andwas designed as a fully automated centralized biosolids dewatering and drying facility for thetwo Winston-Salem plants (Figure 1). Implementation of the final phase of the master planincluded innovative design approaches including centralization of all biosolids treatment andhandling at one facility and the use of three-dimensional (3D) design techniques. The thermaldrying system also incorporated sustainable concepts including the use of digester gas to supplynearly 50% of all fuel usage and heat recovery for heating of the existing digesters and buildingheat. The centralized biosolids treatment facility is in service and has met the long termobjectives for Winston-Salem originally conceived during the comprehensive biosolids masterplan.