Purification of water for human consumption includes various processes of water transformation depending on the contaminants found in the water to be treated. In surface waters from rivers, lakes and springs, it is usually necessary to reduce high levels of solids in suspension, turbidity, color and possibly some metal content such as manganese and iron. Some contaminants are able to be found in groundwater are arsenic, iron and manganese along with other dissolved solid contents.
On the other hand, you can obtain drinking water through desalination of sea water or brackish water with high salt content.
Ecopreneur works actively in developing this market. A wide range of screening equipment is offered for collecting continental or sea waters, including de-griting, clarification, filtration and disinfection systems, to provide different kinds of fully-equipped desalination plants.
Arsenic content has been restricted by drinking water regulations from the World Health Organization. Nowadays, the permissible limit of total arsenic in drinking water in Chile and several other countries in the region is 10 parts per billion (ppb). Advanced technologies are required to reach these levels.
There are different processes for arsenic treatment in drinking water. The most used are:
Oxidation, coagulation, filtration
Adsorption in specific means
There are various specific media for adsorption of water contaminants. Selection of the media should be made with consideration of pH, water composition, flows involved, and the amount of contaminants to be adsorbed. The adsorption media should usually be replaced after the media adsorption sites have been used.
Various membrane technologies are used in water treatment to filter very small solid particles and in water demineralization to separate salt molecules and other dissolved elements to obtain ultra-pure water.
Micro- and Ultrafiltration
The principle of micro- and ultrafiltration is physical separation. It is the pore size of the membrane which will determine when dissolved solids, turbidity and microorganisms are eliminated. Depending on the construction of a rejection layer on the membrane, substances larger than the membrane’s pores will be completely retained, and the smaller ones will be partially retained.
Normally, micro- and ultrafiltration systems are used as pretreatment for reverse osmosis (RO) and nanofiltration (NF) systems or as filtration systems for uses such as drinking water production, tertiary treatment of effluents, biological secondary treatment systems MBR (membrane bioreactor), and others.
Reverse Osmosis (RO) and Nanofiltration (NF)
In a reverse osmosis system, water is forced through a membrane that has a very low permeability to salt and other chemical contaminants. This system makes it possible to separate all contaminants from water, including monovalent ions and molecules, obtaining pure water.
Nanofiltration is a process which uses membranes that have permeability to most monovalent ions. In this way it has the same features as RO membranes permitting the monovalent ions going to the permeate water flow. The operating pressure of NF is lower than that of RO for water that has the same features.
In general terms, there are two kinds of reverse osmosis and nanofiltration membranes. For sea water (SW), membranes are used either for reverse osmosis (SWRO) or nanofiltration (SWNF). For brackish water (BW), BWRO or BWNF membranes are used.
RO and NF systems can be integrated locally or come assembled from factory. They have a wide range of uses and sizes, from a few liters/day to hundreds of liters/second. Information about water type, application and size will permit the selection of a system that will best suits the needs of each project.
Iron and manganese are elements which are often found in groundwater, causing water coloring and formation of precipitates.
There are several processes for iron and manganese removal. The most efficient and most applied applications include the following:
Oxidation - Sand Filtration
Oxidation - Filtration in Greensand
Adsorption in other specific means
Surface water often has a variable amount of suspended solids content depending on the source and seasons of the year. This variation of suspended material content can cause high turbidity levels in the water.
Methods for solids removal are varied, and they will depend on the type of solids contained in the water. The most-used methods for roughing turbidity include the following processes:
Lamella ® Clarifying Plates
Usually the last stage in the production of drinking water is disinfection to meet demanding standards related to the content of bacteria.
The most commonly used disinfectants are chlorine and ultraviolet radiation.
Hypochlorite Dispenser Systems
To optimize the solutions required by customers, Ecopreneur has designed compact purification plants. More than 20 compact treatment modules have been installed in numerous mining camps and industrial facilities.
Total capacity and technology are defined by available water quality. Pressure filters and reverse osmosis systems, among others, are integrated into transportable modules.