Statistical analysis of wastewater treatment plant data

Abstract In this paper, we propose to apply the linear mixed effects model (LMEM) for first time in discipline evaluate wastewater treatment plant (WWTP) data. Because most widely used statistical analyses cannot handle data dependency, as well fixed and random factors, a new approach was essential. We LMEM method analyze three groups of 19 pharmaceuticals personal care products (PPCPs) from California municipal WWTP. studied relationships between five treatments, seasons, PPCPs. The main contributions paper are investigate three-way two-way factor interactions that autoregressive lag 1, AR (1), is suitable variance-covariance structure dependency. While seasons did not affect mean concentration levels treatments ( $$p=0.2540$$ p = 0.2540 ), differed by $$p<0.0001$$ < 0.0001 ) $$p=0.0027$$ 0.0027 ).