The production of clean drinking water

 

Issues:

Drinking water

Drinking water

The production of clean drinking water is becoming increasingly complicated. On the one hand, there are the increasingly demanding consumers: on the other, the service providers are required to guarantee supplies of high quality water free of colour, odour, and aftertaste. The regulator, in the middle of the two, ensures compliance with legislation with respect to the elimination of micropollutants such as pesticides and organic matter found at high levels of concentration in water resources.

Hence, the need to deploy more and more sophisticated technology without losing cost effectiveness. In this respect, the use of activated carbon is an undeniable asset; used as a highly reliable re-agent with a large spectrum of efficiency against numerous molecules.

Solutions:

Playing with water, source of life

Playing with water, source of life

Surface water purification can at times require the application of two types of activated carbons: granular and powder. The use of both types of carbons within a single process ensures greater purification performance. PACs even out peaks in pollution and extend the lifetime of GACs. This can reduce the frequency of reactivation of the GAC and contribute to lower operational costs.

The type of carbons used is determined on a case-by-case basis and takes into account both the quality of the untreated water and the available site area.

Due to its unique expertise in this field, PICA is well placed to meet its client's expectations.

There are three major uses of carbon in the drinking water treatment process :

1. PACs in pre-treatment phase:

As the treatment process involves an agitation stage equal to at least 15 minutes and a clarification stage, PACs can be introduced into the corresponding tank. The volumes are varied over time according to the flow and characteristics of the incoming water. Often PACs are added after an ozonation stage to accelerate the biodegradability of the organic matter.

It will therefore even out peaks in pollution and extend the lifetime of the GAC.

Targeted compounds:

  • pesticides
  • hydrocarbons
  • detergents
  • tastes and odours
  • micropollutants
  • organic materials

Annet sur Marne's drinking water plant uses PICA's activated carbon

Annet sur Marne's drinking water plant uses PICA's activated carbon

Case study: water treatment plant in Annet sur Marne (France, 94):

Since April 2000, a unit has been in service for the introduction of PICA PACs. Injected in the form of barbotine (a water + carbon mixture) during the pre-treatment phase, it adsorbs pesticide molecules which are deposited at the bottom of the decanters. This procedure is particularly useful during flooding when the waters of the Marne collect residual debris.

2. GAC in a classic mono- or bi-layer filter:

An integral part of the treatment plan, activated carbons fulfill the dual function of mechanical retention of suspended materials and adsorption of dissolved pollutants.
 
 
 
 

3. GAC in a biological filter:

Activated carbons in a biological filter set up host bacteria which allow for the metabolisation of biodegradable organic materials. The biological stability of the water is guaranteed, without the risk of forming harmful chlorinated by-products and other compounds which give poor taste characteristics. Moreover, carbon lifetime is extended since materials biodegraded in this way do not saturate the carbon porosity.

Targeted compounds:

  • Suspended materials
  • TOC (Total Organic Carbon)
  • pesticides
  • tastes, odours, colour
  • humic acids
  • chlorinated compounds
  • oxidization bi-products
  • trihalomethanes

Targeted compounds:

  • bDOC (biodegradable Dissolved Organic Carbon)
  • ammonia nitrogen
  • iron

The dedicated line of PICA products and services:

PICAHYDRO