The West Basin Municipal Water District (West Basin) is implementing ozone pretreatment of its non-nitrified secondary effluent as part of an expansion of the Edward C. Little Water Recycling Plant (ECLWRF) in El Segundo, California. This project is intended to improve water production for existing polypropylene microfiltration (MF) membranes in th...

As interest in direct potable reuse (DPR) grows, equivalency criteria for comparing water quality after indirect potable reuse (IPR) and DPR must be developed. An expert panel convened by the National Water Research Institute for a WateReuse Research Foundation project has developed public health criteria for pathogens, such as enteric viruses and ...

In potable reuse, reverse osmosis (RO) is important for system-level salinity management and as a pathogen barrier in the treatment train. Scaling is a key driver of cost for RO systems because it increases energy use and leads to more frequent cleaning and replacement of membrane elements. Phosphate-induced scaling in particular has been identifie...

A traditional two-stage RO system was coupled with a 3rd-stage, semi-batch RO process to increase overall recovery above 92%. The CCD process was integrated as a 3rd-stage as it could achieve higher recoveries due to its cyclical operation pattern, ability to achieve higher cross-flow velocities through recirculation of the concentrate stream, and ...

Reverse osmosis (RO) has played an important role in the practice of potable reuse yet there remains a substantial discrepancy between its actual performance and awarded pathogen log removal credit. The primary objective of this study was to evaluate alternative surrogates, both naturally occurring as well as seeded to RO feed water, that offer hig...

Potable reuse of municipal wastewater has emerged as a viable strategy for increasing the water resource portfolio in arid and water-stressed regions. To protect public health, organic compounds such as disinfection by-products, pharmaceuticals, personal care products, industrial chemicals, and other contaminants of emerging concern should be remo...

Padre Dam Municipal Water District is considering two technologies to achieve a high recovery with reverse osmosis for its upcoming advanced water purification facility. Pilot testing from 2016-2017 at Padre Dam?s demonstration facility has shown that 95% recovery is possible with either a closed circuit desalination process and a conventional 2-st...

The objective of this study is to lower the energy and chemical use for the Full Advanced Train, required in California for potable reuse. The study offers an innovative approach to mitigate biological and organic fouling of membrane systems and enhance process water quality leading to reduced operating and maintenance (O&M) costs. This is accompli...

The current study summarizes findings of over 9-month long optimization study evaluating different chemical dosing strategies to address common scalants, such as calcium phosphate, on reverse osmosis membrane systems used in municipal wastewater treatment for potable reuse. The type of project testing different dose strategies in this case at demon...

The abstract discusses the relationship between upstream ozone dose and reverse osmosis (RO) permeate total organic carbon (TOC) concentration at the Pure Water Monterey Advanced Water Purification Demonstration Facility. Ozone is one technology available to reduce lowpressure membrane filtration (MF) fouling; however, it also increases RO permeate...

Biological growth on reverse osmosis membranes can lead to many negative operational changes. Common practice to control biofouling is to maintain a chloramine residual in the feed water, however this can be damaging to the membrane surface overtime, ultimately leading to shortened life of the membranes. This presentation describes the use of short...

This paper will focus on brining an important issue of oxidative damage of RO membranes by the often overlooked bromamines residual that can form in waters containing high levels of bromide, such as municipal wastewater. The key issue for RO system operators and managers is understanding how the potential for the formation bromamines residual depen...

The proliferation of water reuse applications has introduced a growing need to provide education and training on operating and maintaining the treatment processes in these treatment trains. Membrane filtration and reverse osmosis are essential components of the advanced treatment trains used in water reuse. There is a growing demand for training ma...