Carollo EngineersLittle Rock Water Reclamation AuthorityGeorgia Institute of TechnologyCarollo Engineers
Toshio Shimada;Walter B. Collins;Spyros G. Pavlostathis;Rodolfo E. Kilian
The solids handling facility at the Fourche Creek Wastewater Treatment Facility (FCWTF) receives primary sludge (PS) and waste activated sludge (WAS) that is generated on site and transferred from the Adams Field Wastewater Treatment Facility (AFWTF). The facility also receives an industrial waste stream generated by a rice processing facility. The impact that receiving this industrial waste stream has on the anaerobic digester capacity and the liquid treatment process performance was evaluated through biodegradability test assays and process and operation data analyses. During the evaluated period, the FCWTF primary anaerobic digesters produced biosolids that meet the Class В quality criteria and the average digester loading rate was below the typical design criteria for conventional mesophilic digesters. The biodegradability tests results showed that the industrial waste was degraded very rapidly (less than 10 days) compared to the municipal sludge (27 days). In addition, the test results showed a lower degradability in the tests without industrial waste (53.5 to 60.5 percent) compared to those with industrial waste (60.6 to 67.6 percent). These tests indicated that the industrial waste can be fed at high doses without inhibiting the anaerobic digestion process. However, industrial waste needs to be thickened prior to feeding it to the anaerobic digesters to maximize the volatile solids reduction (VSR) and methane capture in the digesters.