An emerging issue is the release of nanomaterials from consumer products into the environment. Initial studies have shown nanoparticles to be toxic to multiple species, including bacteria, fish, and humans. Nanoparticles are becoming more prevalent in common consumer goods; therefore, understanding the interactions between nanomaterials and microbial communities in engineered systems (e.g. septic tank) can indicate the consequences of released nanomaterials on wastewater treatment processes (WWTPs). This study investigates the effects of three copper particles on the function and operation of a model septic tank at environmentally relevant concentrations. These particles were chosen to determine effects between the nanoparticle-Cu, the bulk size (microparticle Cu), and the ionic form (Cu(OH)2). In addition, the copper particles were chosen because of relevance to real world applications; Cu particles are found in numerous household products that may enter septic tanks.
With about 20% of American households using septic systems, maintaining the function of these onsite wastewater treatment systems is critical for sanitation. Septic system analysis included the evaluation of water quality parameters (total organic carbon, biological oxygen demand, pH, alkalinity, total cell concentration, and total suspended solids). Additional microbial community characterization techniques were also used to detect changes in and relationships between the septic tank function and microbial community phenotype/genotype. Initial analyses indicate that Cu causes significant changes in the septic tank performance regarding pH, biological oxygen demand, and community genotype; this may indicate that the particles cause a disruption in septic tank function, leading to improper waste treatment and groundwater contamination.
