Integrated Modeling Of Ozonation For Optimization Of Drinking Water Treatment

Access to safe drinking water is critical to survival, and its deprivation could affect the health, food security, and livelihoods of human beings. India achieved 93% coverage of access to improved water supply in rural areas in 2015 towards fulfilling its commitment under the Millennium Development Goal1. However, with reference to safely managed drinking water (improved water supply located on-premises, available when needed and free of contamination) as per Sustainable Development Goal, India still has major targets to achieve, and is geared up to accomplish the same by the end of 2024. With the shift from the Millennium Development Goals (MDGs) to the Sustainable Development Goals (SDGs) less than half of the total rural households in the country have access to safely managed drinking water (improved water supply located on-premises, available when needed and free of contamination).

All over the world the presence of arsenic in water sources for human consumption has been raising great concern in terms of public health since many epidemiologic studies confirm the potential carcinogenic effect of arsenic. Because arsenic removal is the most frequent option for safe drinking water, the development of more efficient and sustainable technologies is extremely important. Membrane separation processes are suitable for water treatment because they can provide an absolute barrier for bacteria and viruses, besides removing turbidity and colour. Their application is a promising technology in arsenic removal since it does not require the addition of chemical reagents nor the preliminary oxidation of arsenite required in conventional treatment options. However, since membrane technologies such as reverse osmosis can be a very expensive and unsustainable treatment option for small water supply systems, it becomes crucial that alternative methods are developed. This work presents a few conclusions based on a laboratorial study performed to evaluate the efficiency of arsenic removal using ultrafiltration, microfiltration and solar oxidation processes under different experimental conditions for relevant parameters. The results showed removal efficiencies higher than 90%. Key-words: safe drinking water, arsenic removal, membranes, public health.

Surging population, energy demands, and climate change will push us, ever more urgently, to find new approaches to meet growing water demands. Most often, this will involve harvesting lower quality or impaired water supplies (e.g., seawater or brackish groundwater) as a source for drinking water. Recently desalination using membrane-based processes (e.g., reverse osmosis [RO], electrodialysis [ED], and nanofiltration [NF]) has shown promise for providing additional sources of fresh water across the United States. However, the current membrane separation processes are commonly energy intensive and produce large volumes of concentrated brine which poses unique challenges. Particularly in land-locked urban center brine disposal often relyes on surface water discharge or deep-well injection which pose economic and practical difficulties for wide-spread adoption of such technologies. Thus, there is an urgent need for energy-efficient desalination technologies that reduce the amount of concentrate produced, or identify cost-effective solutions for concentrate management.

In efforts to make package plants more compact, affordable and easier to operate and maintain, it has been noted that the design and performance of some of these plants containing conventional treatment processes is sometimes compromised if technical expertise in this regard is lacking. Generally, there are several risks associated with poorly designed treatment systems, including loss of production, poor safety and compromised equipment and process unit efficiency with associated higher operating and maintenance costs. These risks have more severe consequences in the case of desalination (including water reclamation and water re-use) package plants. The objective of this project is to develop a set of guidelines to assist municipalities, water treatment practitioners, designers and package plant manufacturers in the specification and design of appropriate unit processes and operating parameters to fit the influent water quality, operating environment and other special treatment requirements.