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The aim of the study was to understand the removal characteristics of engineered nanoparticles (ENP) from sludge treatment processes in wastewater treatment plants (WWTP). Removal of ENP (TiO2, ZnO) was tested on primary and secondary sludge, using differential sedimentation experiments to quantify the attachment of ENP to sludge particulates. To better understand the attachment characteristics, aquatic conditions such as mixed liquid suspended solid concentration, and Ionic strength of the wastewater, were varied to replicate different field conditions of WWTPs. Results showed different degrees of multilayer attachment to sludge surfaces based on the experimental conditions. To verify the effect of ENP surface characters with the sludge attachment, SiO2, ZnO, and TiO2 were tested, showing SiO2 with the highest amount of attachment regardless of its surface charge. With the variation of sludge concentration, up to four degrees of magnitude in sorption was observed. Salt concentrations also showed high impacts on the sorption, where the sorption is decreased by half when doubling the salt concentration. The findings of the current research may aid in understanding the fate of engineered nanoparticles in wastewater treatment plants.

Polymeric materials are widely used in contact with water at home (e.g., shower hose, plumbing, etc.). Organic matter eluted from polymeric materials may release carbon sources for microorganisms and cause biofilm formation in our household water systems. Therefore, further understanding of the organic matter derived from polymeric materials in water distribution systems is needed. In this study, BioMig was used to investigate the elution of carbonaceous matter, through migration potential (MP) experiments, and the possibility of microbial growth, through biomass formation potential (BFP). Additional analysis was also conducted on the eluted organic matter to better understand the relationship between the MP and BFP. Four different piping materials were used in the experiments each composed of polyethylene (PE), chlorinated polyvinyl chloride (CPVC), ethylene propylene diene monomer (EPDM) rubber and natural latex. Results showed that the total amount of elution decreased with selected materials with flexible EPDM, and natural latex having higher elution than PE and CPVC. The assimilable organic carbon (AOC) decreased with time for PE, and CPVC, where EPDM, and natural latex increased. The BFP agreed with the MP, where polymer materials with higher AOC amounts also showed higher biomass formation. [ABSTRACT FROM AUTHOR]