Microplastics in Water and Wastewater is a new title from IWA Publishing.
Find below a blog post from the editors, Hrissi Karapanagioti and Ioannis Kalavrouziotis, all about the book and the need for a global plastic strategy.
Purchase the book or find out more here.
This book contains 13 chapters dealing with the presence of microplastics in the human water cycle and how they reach marine ecosystems even after wastewater undergoes treatment, the effects expected from such transport and the need for a global plastic strategy. The authors include 31 academics and activists on the topic of microplastic pollution. Numbers and facts from the literature as well as their own experience are presented in an informative way to help the reader understand key points of the mess related to this problem.
Water is a unique resource that circulates around various environmental compartments. Poor wastewater management leads to liquid pollution whilst, conversely, sustainable wastewater management can prevent liquid pollution. It seems that marine pollution from plastics and microplastics have received increased attention during the last decade. Rivers and wastewater have been identified as major sources of land-based marine plastic pollution. Identifying sources and understanding them better can help us decide on ways to prevent pollution. Thus, the main body of this book aims to describe the transport and fate of microplastics in freshwater and wastewater. At the same time, as most people do, the three book chapters before the last one explore the possible impact on humans and on the environment. Finally, since the most powerful tool for battling pollution is appropriate regulation, the final chapter was added expanding on the existing regulations and effective initiatives.
Water uses in homes include drinking, washing dishes, washing clothes, personal hygiene, house cleaning, cooking and toilet flushing. These activities turn drinking water into wastewater, including the addition of dissolved and particulate organic matter, suspended solids, microbes, dissolved salts that increase conductivity, nutrients, surfactants and micropollutants such as caffeine, antibiotics, cosmetics, pesticides and disinfectants, etc. Wastewater is collected from each house and, by gravity, it flows towards the nearby wastewater treatment plant (WWTP) using water pipes. Municipal WWTPs are expected to lower the concentration of suspended solids and dissolved organic matter in the water. In some cases, nutrient and microbe removal is required by national or local regulations. Examples of the most common treatment processes include screening, coagulation, flocculation, sedimentation, disinfection, aeration and biological treatment. After treatment is finalized, the effluent is sent via pipeline to the receiver which is usually a water body such as a river, a creek, a lake or the sea. Systems that are designed to manage storm and high precipitation events are potential entry routes for microplastics into rivers. This is because the runoff from roads and urban areas is often transferred directly to rivers to prevent flooding within populated areas, often bypassing treatment systems. Wastewater discharge pipes, WWTPs overflow systems and rivers act as the primary conduits through which plastics will travel from land to sea.
WWTPs do decrease the microplastics concentration in water. In most cases, removal efficiency is more than 98%, but still million of microplastic particles are released to the environment each day from one single WWTP. The incorporation of filtration processes into functionally compliant plants will, at best, only provide marginal improvements in removal efficiencies and, at worst, create unintended operational disruptions. At the same time, thousands of tons of microplastics are released each year to European soils through sludge application. Land runoff can return a significant portion of microplastics to aquatic systems. Also, worldwide only about 15–20% of wastewater is treated and sewage sludge is still disposed at sea. This way, extremely high quantities of microplastics directly reach the aquatic environment.
The above data should help us focus on the most effective measures. Besides increasing the percentage of wastewater treatment in the world and effectively managing sewage sludge, prevention of the use and release of microplastics in water and treatment at the source seem the best solutions.