Developments in wastewater treatment methods

Abstract

Wastewaters are waterborne solids and liquids discharged into sewers that represent the wastes of community life. Wastewater includes dissolved and suspended organic solids, which are “putrescible” or biologically decomposable. Two general categories of wastewaters, not entirely separable, are recognized: domestic and industrial. Wastewater treatment is a process in which the solids in wastewater are partially removed and partially changed by decomposition from highly complex, putrescible, organic solids to mineral or relatively stable organic solids. Primary and secondary treatment removes the majority of BOD and suspended solids found in wastewaters. However, in an increasing number of cases this level of treatment has proved to be insufficient to protect the receiving waters or to provide reusable water for industrial and/or domestic recycling. Thus, additional treatment steps have been added to wastewater treatment plants to provide for further organic and solids removals or to provide for removal of nutrients and/or toxic materials. There have been several new developments in the water treatment field in the last years. Alternatives have presented themselves for classical and conventional water treatment systems. Advanced wastewater treatments have become an area of global focus as individuals, communities, industries and nations strive for ways to keep essential resources available and suitable for use. Advanced wastewater treatment technology, coupled with wastewater reduction and water recycling initiatives, offer hope of slowing, and perhaps halting, the inevitable loss of usable water. Membrane technologies are well suited to the recycling and reuse of waste water. Membranes can selectively separate components over a wide range of particle sizes and molecular weights. Membrane technology has become a dignified separation technology over the past decennia. The main force of membrane technology is the fact that it works without the addition of chemicals, with relatively low energy use and easy and well-arranged process conduction. This paper covers all advanced methods of wastewater treatments and reuse.