Treatment of Pharmaceuticals, Personal Care Products and Other Microconstituents – What Technologies are Working?

Over the last five years, the authors have been involved with treatability testing, process modeling and design of state-of-the-art treatment systems for removal of pharmaceutical actives and other microconstituents. The majority of the work was done on pharmaceutical and Chemical wastewater. Municipal wastewater work will also be discussed. This paper presents a Summary of work performed from the laboratory bench scale testing to pilot testing to design and full scale operations data. Cost and economics will be presented for the following technologies:Biological TreatmentAdvanced Oxidation Processes (AOP) using Ozone and UV/Hydrogen PeroxideUltrasoundUltrafiltration and Reverse OsmosisCarbon AdsorptionIndustries and municipalities are faced with many technology choices today for organics and nutrient removal. Microconstituents including active pharmaceutical ingredients (APIs) are becoming a concern and are being evaluated by EPA for future regulations. EPA has already issued Draft Water Quality Criteria for nonylphenol. Some industries, such as pharmaceutical, have been proactive and are already implementing treatment to control microconstituents entering the environment. Municipalities are studying the removal of microconstituents through treatment processes including what is contained in biosolids for land application and composting. There are numerous activated sludge process configurations being used today including: conventional activated sludge (both plug flow and completely mixed), fixed film and membrane systems, and sequencing batch reactors (SBRs) to name a few.Dynamic modeling of wastewater treatment plants (WWTPs) also a trend that offers valuable insights into plant operations, trouble-shooting, optimizing plant process operations, and training plant staff. The application of the currently published activated sludge models (i.e., BIOWIN and GPSX) to the modeling of plants treating domestic wastewater has been well documented. Conversely, the application of these models to the simulation of facilities treating industrial wastewaters has been less common. The simulation of industrial activated sludge plants poses special challenges due to the unique and highly variable nature of the wastewater and the extreme operating conditions often encountered. This paper will discuss the special challenges associated with modeling industrial and municipal WWTPs, highlight the model enhancements often required to handle microconstituents including APIs, provide examples of pilot-testing, scale-up, design, lessons learned, modeling and outline future modeling trends including:Tracking the dynamic fate of specific trace organic compounds (including metabolite formation and removal;Modeling the effect of inhibitory levels of substances on biological competence, contaminant fate and biomass settling characteristics; andOn–line modeling with potential to include warnings of imminent upsets and knowledge-based solutions.Modeling tools such as BIOWIN, GPSX, Water 9 and TOXCHEM are utilized more in the design and troubleshooting of wastewater treatment systems. The use of these models and the selection of the best treatment technologies require a good understanding of the basic principles of biological treatment for organics and nutrients removal. These models are now being applied to understand the fate and removal mechanism of microconstituents through POTWs and industrial wastewater plants.Removal of COD and BOD is still used to design industrial treatment plants, however, effluent limitation guidelines and permits also require design for removal of specific organic constituents such as benzene, toluene, phenol and other industrial categorical parameters. The modeling tools contain the basic process design equations and variables such as: biodegradation kinetic and rates, oxygen utilization coefficients, sludge yield, temperature and dissolved oxygen corrections, etc. which has not changed over the years. The available modeling tools also allow the user to perform time-variable simulations and sensitivity analysis to design parameters to help decision-makers select the best technology solution. The models now include the various biological treatment processes including: activated sludge (plug flow and completely mixed); SBRs, MBR; MBBRs; and others. The modeling tools now being used for microconstituents and some case studies of how this is done will be presented.