Despite popular belief, there are many places in Canada where access to clean water is difficult for some people. Whether you're thinking of certain First Nations communities, mining camps, logging camps, or any other remote population cluster, access to drinking water is sometimes difficult.
Alors, avant d’entamer un projet d’acquisition d’un système de traitement d’eau pour fournir l’eau potable à ce type de communautés, il faut prendre en compte bien des aspects. Autrement dit, il est important de pouvoir répondre à plusieurs questions. A priori, vous devriez être en mesure de savoir combien d’eau la communauté nécessite, il faut aussi connaitre les contaminants qui doivent être retirés et savoir si les changements saisonniers peuvent affecter l’eau d’alimentation. Enfin, n’oubliez surtout pas de vous informer et vous conformer aux normes gouvernementales auxquelles vous seriez soumis.
Water Per Capita
Generally, the amount of water needed for any given camp is calculated based on the number of people in the camp and the changes that may occur in the following decades. Very often, local governments have regulations at the provincial level to determine requirements based on the number of people on the site.
For example, in Quebec, the Guide de conception des installations de production d'eau potable provides that when a new water service is installed, the total needs must be estimated by taking into account projections over 30 years. Furthermore, Statistics Canada revealed in 2019 that the average daily water consumption per capita was 411 litres. This consumption includes industrial, commercial, residential and any other type of water use provided by public services. For your information, the residential sector used 215 litres of the 411 litres used daily in 2019.
Knowing this data will help you estimate how much water you need to meet your drinking water needs. Once you have completed your estimates, the next step is to focus on the contaminants that need to be removed and the amount of them.
Contaminants
Since it is impossible to predict with certainty which contaminants you will find without laboratory testing, we will use a more general approach to help you identify some of the differences between where contaminants come from, their impact and possible changes to your water supply.
The source of your water
Although it may seem trivial, the way you draw your water has a huge impact on the contaminants that can be found in it.
L'eau de surface
Surface water qualifies as any water drawn from a surface reservoir. This could be a lake, river, reservoir or any other type of surface water accumulation. Some of the key characteristics of surface water are that it is often in direct contact with sources of organic contamination. These sources can be of a floral, animal or human nature. As a matter of fact, the presence of any human activity can be the source of contamination of a reservoir since the runoff of rainwater allows the transport of contaminants. In addition to human activities, the presence of animals is not without impact. Animals leave organic traces wherever they go. Again, whether we think of rainwater runoff carrying organic matter from animal activity, or an animal carcass disintegrating in the water, wildlife activity around surface waters has a significant impact on its contamination.
In addition to this mix, seasonal changes can also present a challenge when the feed water comes from the surface. For example, spring snowmelt will impact reservoir water levels, while winter snowpack will reduce soil erosion and contaminants on the soil. In other words, the water may be less contaminated in the winter than in the spring during snowmelt.
Due to the types of contaminants found in surface water and the changes caused by the seasons, it will always look dirtier than groundwater. It will also contain larger contaminants. Knowing this, when a surface water supply is chosen, it is common to require primary filtration in order to protect subsequent equipment and to make it cost effective. Since we will not be discussing the subject of primary filtration in detail in this article, we suggest that you consult this article presenting the differences between 5 technologies that can perform primary filtration: cartridge filters, media filters, AMF, disc filters and screen filters.
Article : Types of filters : Cartridge VS Media Vs ...
Groundwater
In the event that groundwater is chosen as the preferred source of water, geological studies must be conducted to determine if the project is feasible, as not all soils can provide sufficient water output for your needs. Secondly, although groundwater may appear to be more suitable for drinking because it contains virtually no suspended solids, the total dissolved solids (TDS) in groundwater are often much more concentrated and dangerous.
Lorsque l’eau s’écoule dans les sols pour aller s’accumuler dans un réservoir souterrain, elle cause l’érosion des minéraux avec lesquels elle rentre en contact. En fonction des types de sols et minéraux se retrouvant à l’endroit étudier, on peut retrouver des concentrations d'arsenic, ammoniac de sel, de métaux lourds ou de bien d’autres types de contaminants.
Drinking Water Standards
In general, in order to produce water that is classified as drinking water, certain guidelines must be followed that specify the maximum levels of contaminants that can be found in water. For more details on contaminants and their acceptable concentrations, consult the document below which was developed by Health Canada.
A simple generalization is that watercolour, minerals and biological contaminants must be removed. However, once these contaminants are removed, you must ask yourself: what to do with the contaminants? Effluent concentration standards must also be met. For more information on effluent discharge standards and legislation, here is a link to the Wastewater Regulation Overview.
Water Treatment Technologies
It is important to remember that there is no miracle solution and that the technology chosen should be based on your needs and your situation. With this in mind, here are a few examples of common technologies for the production of drinking water.
Often, for the extraction of organic compounds and colour, coagulation/flocculation will be found in very large systems. For smaller systems, nanofiltration cartridge filters and reverse osmosis are commonly used. Ion exchangers with special media can also be found. For mineral extraction, again, reverse osmosis or ion exchangers with the appropriate media for minerals can be used.
Biological contaminants such as viruses, bacteria or protozoa are a bit more complex to extract. Depending on the amount of biological contaminants, a disinfection system such as UV irradiation chlorination or ozonation may be sufficient. On the other hand, if there is a large quantity of biological contaminants, after the deactivation of these contaminants with the help of one of the technologies mentioned above, it is highly recommended to add a fine filtration in order to extract the "dead" residues, without which, it can have a cellular reactivation and, thus, recontamination.
What to Keep in Mind
Autrement dit, les technologies permettant la production d’eau potable sont très variées. La sélection du type de technologie et la complexité d’un de ces systèmes dépendent de la qualité de l’eau d’alimentation de celui-ci. Donc, ce qui importe avant la sélection d’une technologie de traitement d’eau est de bien connaître et comprendre sa situation.
Remember that before anything else, you need to make sure that the project is feasible. To do this, make sure you consider all the pieces of the project. Here's a quick rundown of the aspects that need to be considered:
First and foremost, you need to start by identifying your water
needs. Don't forget to consider the needs according to the laws or recommendations
on this subject.- Next, identify a water source and confirm that this source has the capacity to provide the flow you need in accordance with your future projections. Without this capacity, you will need to identify a new water source.
- Once you have identified a suitable water source, perform the necessary tests to determine what contaminants need to be removed and in what quantities. Again, be sure to follow the regulations you are subject to.
- Now that the contaminants to be extracted are known, identify the wastewater discharge regulations that are imposed on you. This step can have an impact on the technology to be used since some technologies allow the complete extraction of certain contaminants while others allow the recovery of certain contaminants such as heavy metals.
- Once all these steps are completed, all you have to do is choose the technology you want. At this stage, we advise you to call on experts to advise you and direct you to the most advantageous solution for your situation.
As you have understood, the production of drinking water is highly regulated and so is the discharge of wastewater. These regulations are not in vain, they exist to protect human health and the environment, whether from the point of view of consumption or indirect impacts related to discharges.
Now that you better understand the importance of
knowing and understanding your situation before considering a technology, you
will be able to better choose your optimal solution. The only thing missing is
information on the different aspects that can affect the operating and capital
costs when purchasing a water treatment system!
Guess what, we've already prepared it for you!A