Microbial Activity in Granular Activated Carbon Filters in 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.

This paper aims at analyzing the drinking water issue in the Mediterranean region, highlighting the principal problems and the appropriate technologies applicable in the different countries. The countries of this area are characterized by a huge variety from social, cultural, economic and environmental point of view. In particular, water distribution is inhomogeneous between the North, East, and South; even the type of water sources and the related quantity and quality problems differ country by country. Potable water comes from brackish and seawater, surface water, groundwater and water reservoirs with each source face different issues. The main problem of brackish and seawater for example is the high salinity and the contamination by disinfection byproducts, in addition to the microbiological and chemical contamination due to human activities that characterize also other surface water sources. Groundwater is also affected by human activity and it is not exempted from salinity because of the water intrusion. Moreover, water reservoirs are often contaminated by seasonal algal blooms. Technologies applied for drinking water treatment vary country by country. The paper presents the main treatment processes associated with the main water pollutants, according to the Mediterranean region. Case studies of drinking water treatment plants are also analyzed, presenting alternative technologies appropriate for specific contexts, among others. The characteristics of each specific context should be carefully analyzed in order to develop the most appropriate technologies; high-end technologies for drinking water treatment may not be applied equally to all countries or communities of the Mediterranean region.

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.

Adsorption method of purify water relies mainly on the adsorbent to adsorb the impurities in the water, this paper introduces the latest research progress both at home and abroad, such as activated carbon, chitosan, zeolites, clay minerals plant-based, industrial waste . These adsorbent type will play a more and more important role in water treatment in the future.

New regulations pursuant to The Drinking Water Safety Act, administered by the Office of Drinking Water, resulted in changes to the approval, licensing, monitoring, record-keeping and reporting requirements for drinking water systems in Manitoba. It is recognized that many small drinking water systems may not have the same level of access to technical services and resources as larger public water systems. This manual of best practices (a comprehensive, integrated and co-operative approach to continuous improvement of all facets of operations for delivering superior standards of performance) is to assist small drinking water systems with regulatory, management and operational challenges.