Adsorbent Material Used In Water Treatment-A Review

In the presence of free oxygen, aerobic bacteria use the organic matter found in wastewater as “food”. The BOD test is an estimate of the “food” available in the sample. The more “food” present in the waste, the more Dissolved Oxygen (DO) will be required. The BOD test measures the strength of the wastewater by measuring the amount of oxygen used by the bacteria as they stabilize the organic matter under controlled conditions of time and temperature.

Introduction: Activated carbon filtration (AC) is effective in reducing certain organic chemicals and chlorine in water. It can also reduce the quantity of lead in water although most lead-reducing systems use another filter medium in addition to carbon. Water is passed through granular or block carbon material to reduce toxic compounds as well as harmless taste- and odor-producing chemicals. This fact sheet discusses the principles and processes of typical activated carbon filtration systems.

• Describe how water treatment plants comply with their minimum federal and state monitoring requirements. • List the three ways in which management ensures that the staff complies with monitoring requirements. • Discuss reporting requirements when complying with federal and state regulations.

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.

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.