Nataša Uranjek, B.Sc. – Drinking Water Preparation and Wastewater Treatment Technologies
My name is Nataša, my surname is Uranjek, and I am employed in the utility company to the company Velenje as head of the department for technologies and control. Of course, as a chemist, I am interested in many things, and in my free time, I am also very interested I like to go to the guest house, to Uhribe, to ride my bike, also in winter I ski and, of course, I also like to wander and swim in the sea. In the field of my work, of course, it is related to both chemistry and everything to others, what is in the surrounding area and my own, I will say free time, I also dedicate myself to the Slovenian Society for Water Protection as a member executive committee, where we take care or, as an organization, strive to preserve Slovenian waters. I decided to study chemical engineering because I was young very interested in what is happening around us and what is happening around us and what is happening around us and what is happening around us. I was interested in chemistry, I was interested in medicine, I was interested in it pharmacy, but in the end I somehow decided on chemistry because I it seemed that everything was connected and because in medicine I sometimes I felt too much with people, if something hurt, I thought it was I'm not really into this field. I didn't even know that it would be different later on during my studies my field is precisely wastewater treatment and drinking water.
I will say that somehow life brought it, but it never happened to me it was a pity, because this is a very, very interesting field and it hasn't happened yet happened to spend a day at work and not know what to do. In our work, we deal with everything that happens in the field of cleaning waste water, preparation of drinking water, monitoring of these systems and so on of course, we also have district heating in our company, including a medium that water is used, we take care of that too. In our work, it also appears that we advise our colleagues from of smaller utility companies that need some help at the same time also in the establishment and in the planning and design of new cleaning plants devices, new drinking water supply systems, I am also active here as a responsible engineer in this field. Everything that humans wash ends up in municipal waste water or rather, we pour it into our drains and drop it into our larger nurseries. This means that wastewater is actually a great cocktail of everything comes in, so we don't even know exactly what we have, because there's a lot the things we pour into the drains then also react with each other and some new compounds are formed, for which we do not even know what effect they have on us, what impact do they have on the environment or rather over the years, you these influences if further prove more. All these chemicals that we humans use in our daily lives life, both in cosmetics and in washing, all this then of course finds in this waste water that we collect.
We collect it in sewage systems, take it to the treatment plant, there we try to clean this water as much as possible, but not all of it we have to remove and therefore some of these chemicals and everything that is in the water, flows into our waterways. Treatment plants for municipal waste water are based on biological cleaning processes. So, the bottom line is that we are actually removing the bases that bacteria can use it as a nutrient, as food and in the cleaning process carbon is mainly removed from these waters, municipal wastewater nitrogen and phosphorus compounds.
For these purposes, we have established monitoring, which means planned we classify waste water, in these classifications we define individual parameters, such as I have already listed, that is, the organic distribution, which we determine in in the form of chemical oxygen demand and biochemical oxygen demand, and then all forms of nitrogen such as nitrate, nitrite, total nitrogen, orthophosphates, total phosphorus and, of course, also dissolved amounts of oxygen in this water, which is released into waterways, as well as pH and so on electrical conductivity. These monitorings are essentially foreseen or planned. We also have online analyzers, with which you can do everything time, we continuously measure the concentrations of these parameters, which are described them.
This is mainly because it is also necessary for the management itself wastewater treatment technologies. If it happens that some parameter exceeds the nominal value, of course that means immediate action is required. This means that technology and our other colleagues from the field of the mechanical field and the electrical field, we obtain, review the records, let's review what was happening with each parameter and, of course, regarding to the best of our knowledge, let's evaluate what could be the reason that this happened deviations. If we find out what the cause is, of course we try to eliminate it as quickly as possible. We do not know exactly what is causing the discrepancy in operation cause, and of course we also connect with our colleagues who they work on the sewage system and we send them to the field, yes they check if it is possible that something is known, that something is happening on the island itself sewage system, that maybe some contaminant has released something into our system, which does not belong. Wastewater, as I mentioned earlier, contains a great cocktail of all of them chemicals that we put into our percentages.
I think it's so many different types of chemicals that I don't really we can determine all of them with these analyzes of ours, which we carry out at monitoring. The problem is that basically all these substances that come into it are waste water, you can't just determine it with one method. Every substance that we want to analyze, there is one for every substance special analysis and if we do not know exactly what we are actually looking for in these waste water, it's something that actually doesn't even lead to it we can tell because we're not looking in the right way, if you put it that way.
In the monitoring we are currently carrying out on these wastewaters, it is the problem is also that all the pollutants that come with the waste water, that they are the remains of medicines, chemicals that we use in our everyday life in life, in cleaning, in cosmetics. All these chemicals are so complex and, these monitorings that are now prescribed for waste water, are not part of regular investigations. These substances, which, of course, are also potentially dangerous substances for the environment and also for man and for all other animals, but they are determined more than not in in the context of research projects, where in this way we can also find out what is actually in this waste water. Not only these substances, that is to say, as far as nutrients are concerned, which are key for river eutrophication, but also other chemicals, including residues medicines, residues or parts of cosmetics, where they work very hard degradable chemicals, this is usually not measured.
However, we have also participated in such research where The Jožef Štefan Institute carried out mortification in waste water of drug residues, also the remains of some drugs that people use. Or some people use it for their own life, for improvement, or else they think they are improving their lives. That is to say, these substances must be completely specific and with special methods conduct research. The problem is that these compounds are present in such low amounts concentrations, that they are very difficult even when you know, when you are looking for them, difficult to determine. And these samples, which the Institute receives, must of course first be correct to ask And it is also a key part of the very analysis of these chemicals, that the sample prepare correctly. It is not as easy as it might sound, as we sometimes think on television, these various series, CSI Miami and something like that, where they collect the sample, put it in a miracle device and then it determines everything.
In the real world, it doesn't work like that, you really have to search in a targeted way the compounds we want to determine. The knowledge that I acquired through I will say formal education, but also through work, of course also has an impact on mine life, to choose my food, to choose cosmetics, to choose cleaned up. As we hear now in these last years many times, I try to I eat locally produced food, seasonally produced food. I know that then there are as few pesticides as possible, as few others as possible artificial fertilizers and non- residual substances, which, I will say, pollute in such a way food and, as a result, my organism and, of course, my children's as well. And also with cosmetics, that only what is used is used the most necessary.
For more than 20 years, I have not used any fabric softeners when washing, because they are practically unnecessary. Apart from the fact that they smell, I don't think there is any other special function, maybe with what kind of towel, maybe a little softer, but if we give it, that the towel, perhaps only for a short time in the dryer, is the same effect. I avoid everything that is not necessary. Because if we don't use it, then we won't pollute with it either environment, we will not leave any negative consequences for our children, for their life, for our life. So I kind of strive to only use what's real i need Even with cosmetics, when I use them, I look at what is stated on declaration, I usually buy things I know.
I don't experiment much. But if I decide to buy something new, then I try to buy something as natural as possible, I check what is inside, if there are any inside substances I don't want her to use. Because we also need to know that, not only do we consume things, but also through them substances penetrate our skin into our body.
And they also wash into the water when we spread it. And it all ends up in our waste water. As a result, even later, because the water is constantly circulating, because we have na the earth only has one environment, then this dirt comes back to us. In municipal wastewater treatment, the key is still that we remove substances, i.e.
what I mentioned earlier, nutrients, se true carbon, nitrogen and phosphorus substances. For now, this is the essence of the treatment, this biological treatment of waste water. If we want or if we want to remove everything from the waste water what we actually put into waste with this modern way of life water, these processes must of course be upgraded. It is necessary to upgrade the procedures with more, shall I say, more expensive ones, with modern technologies, which, of course, is not so easy. Everything needs to be updated, all these cleaning devices, and all this again related to money. In some areas even these simple or, shall I say, basic ones pollutants are not removed from the waste water, what else would it be upgraded.
Because we need to know that these modern, or rather, these repulsive chemicals that man produces, it is not so easy to decompose. It is necessary to use various procedures, just as there are advanced collaborations. Oxidation processes, including activated carbon, are mainly different technologies that are not needed or would not be needed if these we would not put chemicals in the waste water. That is to say,
it is necessary to think more in this direction, as well as with waste, so that we do not create it or that we do not put chemicals in it wastewater, but not how we will clean it. Of course, they can be cleaned and also strive to... in the field of waste water treatment, to the fact that it would already be at the source, that is to say where these complex organic substances are produced, as, for example, in pharmacy, where medicines are produced, to dispose of those waste water cleaned in such a way suitable, for suitable technology and that with what and of this goes into waste water, municipal waste water. Some municipal waste water is just what people in their work, we produce in our lives.
It is also important to know that we don't have to do it to the fullest to avoid, because we consume people, we consume medicines, we consume various things others, I will say, even substances that we don't want and then they find out about it of our metabolism, we also excrete it through the body, I am characterized by excreta, and this gets into the waste water, so in any case it will need to be cleaned to upgrade devices with effects, with more efficient technologies for removing these new, modern pollutants. These modern pollutants, as well as microplastics, are found in wastewater belongs to these substances, it has not been determined for a long time, or this analysis they perform in a more project- based manner. As I already mentioned, the key is that we try to prevent this, that it even gets into the waste water, even microplastics, you might wonder when you hear the name microplastics, it seems that it's just, I don't know, it's appears in the oceans as leftover plastic, the kind we use, but that's not true. Microplastics also include synthetic clothing fibers. Of course, we have been using these synthetic clothes for many years and with each wash, part of these trains, but with the waste water that dropped from the washing machine, it also finds its way into the waste water that reaches the cleaning devices.
This microplastic is also found in cosmetics, including dental to fall. That is to say, we humans have come to use this plastic almost per barrel, and this is mainly due to its low price. We may end up paying a very high price for this low price of plastic. In the past, natural materials were used for these purposes, for example, in body peelings, they could be used instead of microplastics strain, or we can prepare it ourselves. Coir could also sometimes be used, it was used coconut particles for that abrasion we want to achieve with some cosmetics. Teeth are sometimes rubbed in toothpaste with activated charcoal.
So that's a little bit possible. But maybe a little more expensive. But maybe he wants more of our attention, so that he is not all that he is so much quickly and so much for the price, so much good for us. And that the consequences will only come later over the years. If people use a lot of different ones in their lives of chemicals, even as cleaning agents, then it can also happen, or rather it does sometimes it happens that someone has a lot of these chemicals at home, which of course they do all written expiration dates. And when ever the cleaning of these rooms of ours, our closets, which are carried out already too crowded with all this, then also what can end up in the toilet Kindergarten.
And one liter of such a powerful cleaner can have big consequences on the body smaller sewage treatment plants, for example household sewage treatment plants. Such a smaller one is for one house or for a couple of houses. If such a liter goes into the sewage system. If such a liter goes into the sewage system. which then ends with a larger cleaning device, let's say that it is intended for a whole city of 50,000 people, then it doesn't have that much of an impact.
But everyone has it, so such events must be prevented. In other words, chemicals do not belong in the toilet, cleaning agents do not belong in the toilet, residues bars, varnishes, all this does not belong in the toilet nursery. All this must be cast on ecological islands. We have actions that are called comedies, which also pay for the release of soft. they choose these remnants of paints, medicines, chemicals, and it is necessary to respect.
That is to say, the kindergarten toilet is not a dustbin. WC kindergarten is intended for our needs, our life needs, it is not but this dump, it's not a landfill, it's not a bin. And therefore it is necessary to treat all the means that we use, from cosmetic colors, chemicals, cleaners, as prescribed. That is to say, they are removed in a suitable way, but they do not merge in any way to WC Kindergarten. He mentions what happens if we pour a large amount of one chemicals in percent and that comes to the biological cleaner, the least that can be done what can happen is that it currently exceeds, say, exchange value at the outflow due to which the load is too high. What's worse is that such chemicals can kill this activated sludge he says, biomass, our bacteria, our workers who treat waste water, we kill them with this and of course this means that the cleaning device lasts longer it will no longer function, not just for an hour or a day.
The fact that you are relocating the operation of such a treatment plant means yes you have to grow a large enough number of bacteria and other such microlonisms, which are removed during cleaning, which can also last months. In terms of how vulnerable sewage treatment plants are, or how much they can how we influence it depends very much on its size or on its capacities. Smaller devices are much more sensitive to any such event.
Precisely because of what I meant, the water does not leave the ground to come directly to the biological process itself and can destroy the whole system. As the devices got bigger, not all people made them at the same time mistakes to, say, pour these chemicals down the drains. Therefore, such a thing is dismissed and does not have such a great impact on itself operation of the treatment plant.
Newer cleaning processes will also ensure that the water will certain substances, certain resistant chemicals can be cleaned. As for microplastics, there have always been some devices they use membrane technology, i.e. membrane technologies, wastewater treatment, where at least these particles are called particles microplastics, retained in sewage sludge. Research has shown that even with ordinary biological cleaning plants devices, the majority of microplastics, more than 90%, are retained in this active mud. And the key is then where this active mud goes, even in this active one mud, we deposit it, or in what way we remove it from the system. The activated sludge that is produced is essentially a product of growth microorganisms, microorganisms that feed on our waste, z our sewage and there will always be this mud.
And if we somehow get a lot of microplastic into the waste water, it will a lot of other things too. The trend is also, as I mentioned earlier, that, for example, filters for microplastics are installed in newer washing machines. In other words, we prevent microplastics from entering at all into waste water and in this way we will not have problems with by removing it.
As I already mentioned, these membrane purification devices, at least this part dissolved or undissolved substances are retained, and dissolved substances are retained they always run off into waterways. Now the eco- remediation process, as far as I know it, is practically, biological cleaning is also a kind of eco- remediation. These are essentially procedures with microorganisms, it is not some technology, it is not the use of certain chemicals. Biological processes are mostly used for municipal waste water.
So I really don't know what else I could upgrade here. We can upgrade the cleaning processes themselves with more successful ones, for that matter removal of drug residues and other persistent chemical, compounds. When using mud, i.e. this product of ours, there is no need for cleaning of water, but of course these technological procedures can be used. In the future,
the main aim will be to make sludge from sewage treatment plants larger than 50 thousand population units prescribed, or rather, a mono- burner of this mud will be mandatory. Namely with the aim that all these semi- active substances, all these dangerous substances, are removed, and phosphorus is recycled, which is stored or stored in these microorganisms and we lack it in the environment. Phosphorus is one such compound that can be recycled and which it embeds in every living being and of course it is also important for growing plants and for our food, with this element, so that European the union somehow prescribes that by 2030 it would be mandatory, that is Mandatory sludge incinerator with the aim of recycling phosphorus and pa removing all dangerous substances found in the mud.
Sludge is already used as fertilizer, it can be used as fertilizer, of course under certain conditions, but these conditions are enough now loose, because only the concentration of some heavy metals is measured, and nitrogen and phosphorus, but not the rest, the drug residue is not measured, the residue of microplastics is not measured, we say all this so that it can also pass into plants and, as a result, we also consume it with food in us animals and even in some compounds there is a magnification, se he says that this is imposed and of course the effect increases. A mud slinger. It basically means that the device that will be made or designed exclusively for slag, that is, sludge from sewage treatment plants and nothing else.
This is a specific dedicated device with the purpose of recycling phosphorus. Of course, in all these devices it is strictly observed that it is prevented any or to minimize all emissions. Both in the air and in the water, which is key if we want to preserve as much as possible healthy nature.
When we talk about waste water, we cannot ignore the fact that it is all connected to the fact that we have one water creature on our planet, that is water it circles around us and does not go anywhere and does not come from anywhere. Water also has the characteristic of being a kind of super blunt. Many things dissolve in water and through this also pass from the waste water into the watercourses, the watercourses feed below the watercourse, we pump from the watercourse our drinking water.
So far, most of the drinking water in Slovenia is in good condition, it is good qualities, except for some problems they may have in the east of Slovenia, where it is a lot of agriculture, they live there or have problems with nitrates and also with pesticides. In our area, where we live in the city of Velenje, the water is of good quality. Due to the fact that our area is karst, we have karst water bodies sources, means that this drinking water also has contact with surface water and in this water is microbiologically objectionable after storage.
For these reasons, we are in the past, that is now seven years back on The communal company Velenje, and of course the municipalities of Velenje, Šoštan, Smartly, Paki, we have invested in devices for the preparation of drinking water, where ultrafiltration technology is used. Ultrafiltration technology is water- friendly because that's what it's all about for filtering water. We do not use chemical compounds for preparation, but only water filtered through such tiny holes that essentially everything remains on them, which is undissolved and more. Larger dissolved molecules that can potentially be harmful to health, and of course all viruses and bacteria stay on these membranes. And the water that we then get still has dissolved in it carbonates and other minerals that give water taste and that give water quality, but the water is not microbiologically burdened and that is why we do not have it must use, for example, chlorine for disinfection. Of course, not all of these procedures are convenient.
That's why we get users home every month, I'll say, greetings from of the utility company, i.e. a deposit slip, where essentially no payment is made water as such, but the activities that are necessary for it to water that we prepare and distribute from all users so that in each momentarily they open the tap and drinking water flows out of the water without thought about, but whether it is or not, it requires some resources, energy and in the end money also for all these activities and that's what users pay. This is basically the price of water here. The price of water is, of course, an individual concept, it also depends on how much we have at our disposal. We have a relatively large amount of drinking water available in Slovenia, so we we sometimes think that it is playable, that the price is too high. But if we lived somewhere in Africa or somewhere else, I don't know, even Wednesday of the ocean, where water is prepared by reverse osmosis so that they have something to drink pit, but then you would probably think about it a little differently.
Maybe this price would not be too high for us, because if we look at that one cubic meter of drinking water that flows from the tap in our apartment every moment, that is ten, one cubic meter is one thousand liters of water. It costs about the same as one bottle of water that we buy in the store, liter of water, then we can ask ourselves, is it really that expensive? I don't think so, it's still too cheap. If we are also talking about drinking water, as I already mentioned, it is that we drink we prepare the water to such a quality that it is suitable for drinking, that it is health appropriate and compliant with the drinking water regulations, therefore also in addition to all the preparation, we also need control, and this control is carried out in Slovenia, I would say, on two levels. One level is the management one, that is, internal control, where there are communal ones companies tasked with constantly monitoring the quality of drinking water of water. Namely across all barriers.
Internal control is based on the HACAP system and this requires that the water quality is checked all the way from the catchment to the tap, to the tap user, i.e. what we humans consume. As part of this, of course, monitoring is established where they are carried out measurements of individual parameters that are important depending on which the level of water preparation is In other words, we analyze several parameters in the catchments, from heavy metals, organic matter, microbiological, then pesticides, ammonium nitrogen, nitrates, all these parameters are controlled at the catchment.
Then, during the water preparation process, this, I will say, reduces, or we adapt to what we do and what we want to get out of it water is removed and we also check whether it was successfully implemented. That is to say, this internal control is intended to ensure that we always we check the compliance of this drinking water, compliance with the regulations, health care, and all these parameters, which are preparations, to Ours Of course, we bring such water to the tap for users. Then there is another institution above us, and this is the state one monitoring, which, however, is carried out completely independently of public service providers drinking water services. There, the state places, depending on the number of inhabitants per a certain area of the water management system and also according to these parameters, which are crucial for the state to have data on how they are cared for its citizens and from microbiological quality to chemical quality as well of quality, that is, this monitoring is carried out completely by the state independently of the operator of the water supply system and is also carried out several times annually.
According to individual systems, as I already mentioned, depending on how many people from some water supply system supplies, so much more there are a few. That is to say, we serve more people than we take care of, because it is important that if something goes wrong, there will be more people cured. In Slovenia, according to the data of this state monitoring, which is, of course accessible to everyone on the back page, people can see what's going on is analyzed and what the results are, the key is that these bigger water systems usually have better or more controlled water. As I say, smaller waterworks, even those smaller than 50, are the most vulnerable, similar to falling water. There,
however, the control is a little less, for these smaller settlements, where there are even fewer like 50 users, usually one person takes care of it and then there there may also be some deviations and also from this monitoring of the state, it can be seen that the most non- conforming samples are on these smaller ones waterworks. From time to time they are read aloud. People who have wells in their yard since their grandmothers and children and since we somehow have a trend of wanting to go back to nature, they have too feeling that it would be much better and healthier for them to drink water from this well as if they were drinking water from a water system which they don't know what we are adding them all to. At that time, those people who are somehow still aware that it might exist the possibility that this water is not good or not adequate, they bring ozorce, where they want us to find out whether this water is potable or not.
That's usually how their questions are. Of course, we first talk to everyone and ask them what they are like the purpose of using this water, whether they intend to have this water for drinking or simply, no I know, to irrigate the garden, to water the plants. We usually do in this water, the first indicator is already in the essence microbiological input. That's the question. We also tell customers to bring water when the conditions are right the worst. This means after some rain, when there is a chance for them to be washed off the surface microorganisms or even some fertilizer residues into this water and then it is relevant that we determine what this water is like. It usually happens that this water is not adequate to contain it micro- organisms that are not allowed or that can harm health man.
According to their questions, our children have already drunk this water, and ours grandmothers, we drink it, but it doesn't matter to us, but we would like to know the fair, what is she like. Then we can tell what can happen. Someone who lives and who uses this water, according to time, can also be his the organism develops resistance to these present microorganisms and does not responds. That is to say, he is somehow immune to these microorganisms, which are still from a small one, let's say, he enjoys. But it can happen that this person gets sick or that a new person is born into the family trok, which is of course much more sensitive to such microbiological ones the presence of microorganisms that are in this water, such as, for example, common coliform bacteria, scherichia coli, enterococci, which in water they come as a result of fecal contamination.
And such a person or a child or a person who gets cancer and is his immune system weakened, he can experience very serious consequences. I will say that the easiest thing is that he gets some diarrhea, some hydric a disease that heals with time, but these are the microorganisms that are can be present in water, can also be very insidious. If we have enterococci around and enterococci present in the water, this indicates that that it is in the water, that the water is in contact, in direct contact with faeces. Escherichia coli is a very, very dangerous bacteria. This bacterium can also cause organ failure, it can cause kidney failure, even death. So these things are not to be trifled with.
And even if your children were blunt, maybe it wasn't so much at the time populated this landscape where you now live. There were not so many, I will say, these events that are happening now, these of extreme downpours that wash away everything that is on earth, v to the earth, under the earth, to these supports, these aquifers. Every water we use for drinking is good to know what it is and that it is microbiologically sound. Because the consequences of this can be severe. Years ago,
you may remember that there was also an affair in Europe where a large number of people fell ill with an infection with E. coli, that is, widespread E. coli.
They were also in the hospital and I think they also died. The cause was basically the use of impure water for watering the kummer, if possible just sexual. And therefore we will henceforth know that even so water from the well, if it we use it to water the garden, it is not harmless. And also, if we use it for such, such purposes, the wallet that we harvest over the roofs, it is right to at least occasionally check hers quality, or that we do not use it directly for spraying leafy lettuce, for example, or by parts of plants that they directly we use Such water can be used for watering trees, possibly also point- wise for watering tomatoes, such vegetables that we do not eat. That is, which are not directly exposed to this water. That is to say, it is not so harmless that we consume water that is not examined, for which we do not know what kind of hair it has.
The fact that it is a microblock is important to everyone, why is it so important? Because that's what we get an acute infection. The moment we ingest such a microorganism, we can become infected and we get sick. Other, for example, other dangerous substances that may also be present in drinking water, as well as residues, fertilizers, pesticides, usually have longer period, they need a longer time to get to know each other in terms of health. Of course they are,
undeniably, they should not be used, but this one the microbial factor is the one that is key or that is acute and that in a whole village, a whole settlement, a huge number of people can get sick at a moment's notice. So you really have to be careful here. And if you have any wells, have those waters tested. Also this use of various water sources, I will say streams, as in ours in the environment, we observe that a lot of people stop by the side of the road, while driving in front of the thermal power plant, where there used to be a healing water source, give this taken as a reserve. This healthy water source is not always healthy.
The treated analysis found that the water does not comply with the correct compitni leads, even at one event it was that something was detected oil or residues of some dyes. But when we informed the municipality and when the municipality informed its own users, there were most comments on websites or on To Facebook, that utilities say this because they want to make money. Yes, if that. We, regardless of sending money orders once a month, have somehow also knowledge and we also know what the problem can be with such people water sources, so sometimes we go to find something ourselves, but we get it after some analysis, we see that the water may not be adequate, but we warn you people that he is not good. But what worries me the most is when I sometimes listen to people who got sick, got sick after serious illnesses and then somehow they want to return to nature and they look for all possibilities, they also find some sources, some sources and then they go there and fill their cisterns with this water.
If this water is not checked, then more can be done, sometimes more harm than good. If microorganisms are present in such water, it will a person pours water into a container and then keeps it at room temperature at home, they multiply more. If this water is filtered through devices that are not inspected, which are not maintained in accordance with all instructions and where filters are not changed, then the consumption of such devices can also do more harm than good. In this area too,
we have already had the experience of a man bringing water and water from the tap through the filter device and what did we end up with? The water from the filtered device was full of microorganisms. Because that filter was not changed in accordance with the manufacturer's instructions. Because this filter, if we use it for too long, if we don't change it, then it arises as a kind of breeding ground. We start growing microorganisms on this active corner, because actively ogle is not active all the time, it has a limited period. In the beginning it is active, because that is where these pores are active, where they bind organic matter, but once these pores are filled.
Then it is no longer active and it becomes like we have some balls, tiny balls, where the microorganisms settle. And this person, who was sick anyway, then basically drank even worse water than if you used tap water. Just like using tap water. So so... On this container, do you have a similar certificate for grinding? I don't have a certificate for grinding for drinking water, but a lot of them do I'm drinking.
And the first thing in the morning I do is to… to turn on the tap at home. I always pour a little water first so that it flows out of the pipe, because it is stood there overnight. Then my first meal or whatever I put in my body is water from taps at least two, three children. And I think that's good for me. And I also recommend to everyone else to do this first thing in the morning when they wake up wake up.
We analyze heavy metals and mercury on our cleaning device silver mud and also effluent from the sewage treatment plant. The effluent from the treatment plant has less value or reach concentrations of mercury below the minimum values, even below the limit determinations. In the past, we also detected something in our dehydrated mud of mercury, it is still being measured, the concentrations are still far away sublimits allowed, but I will say, at the time when it is on ours area, I think that was there in 2011 when it became active emptying of septic tanks, at that time we detected a slight increase in our stool mercury concentration value.
From then on, we kind of attributed it to these cesspools, which have been a decade, some not even realizing it was there accumulated this mercury. Also maybe from health centers, I think it's also this one, it's been since then there was some emptying of the septic tank from the medical center, some leftovers, some old, I will say, piles of mud, and that's when we detected someone slight increase, but now, for the last years, I will, for the last ten years, but these concentrations of mercury are, I would say, at the same level, practically at the same level and in our field, we have no problem with that. If it happens that after the ozoring, after getting the ozorons in the beginning treatment plant, or before the treatment plant, and behind the treatment plant when it should if the water were purified, we find that even concentration is possible some tried higher for the device than before, maybe this is also the reason, that the correct retention time at the treatment plant was not taken into account, se he says that we did not take the water that flowed into the treatment plant and waited some time for this water to be purified and then actually took it the same sample of this water, which was at the source, but we may have captured it precisely that more load, which we did not cover during the inflow. That is to say, we always have to, when we take ozarce, whenever we ozarce inflow and outflow, take into account this retention time of waste water on the same sewage treatment plant, because if we look, it can happen that we after the night people are mostly asleep, not active, and this water reaches anyway the water treatment plant itself and if we use this water in the morning as an inflow to the treatment plant and at the same time we take water from the east, we can get, that it is due to the retention time, which can be at the treatment plants even 8 o'clock and no. And what's more, in fact, completely different water flowed from the device than what it is touched the device itself. So here you have to always be very careful when taking it, even if if these are average observations, even 24- hour ones, retention must be taken into account time.
In the case of houses that are outside the agglomerations, that is to say, this is the environment where it is population density is lower, it is still not mandatory sewerage networks and also, which are usually at the end of the style device, houses can still exist with an existing septic tank. Those who are renovating or building anew, it is already for them prescribed that they must have a sewage treatment plant. It was characteristic of the sinners themselves that more than 40% were not able to purify water.
Anaerobic decomposition takes place there, all suspended substances settle out this is how we get rid of waste water, some of it is anaerobic processes, and this water is definitely better, or has a better quality, if we take it out of the closet, as if we took it directly from the house, from of the toilet into the environment. However, this is not enough by today's standards, or rather it is nice if it is better cleaning quality. In this way, we can also upgrade or supplement existing walls with, for example, with plant treatment plants or with treatment beds that they flush this water, to a really good quality. And such water, which then goes into the environment, is certainly much better, like only from the septum. However, in these areas, where the population density is less dense, such as the cleaning system uses a plant- based treatment plant. And that's great.
But we must know that we need a certain area for this. For one person, for one population unit, we need at least two square meters meter of surface, in order to successfully purify such waste water on plant treatment plants. Provided, of course, that this device is properly built, that it has the right ones inclinations that it also has the removal of mechanical particles before it, because such mechanical particles, if they enter a plant treatment plant, can they block its active part, that is, this opposition.
The water inside can clog prematurely and, of course, then the device it cannot work. Because there are basically two systems in the plant treatment plant, which treat waste water. One is these plants that are planted, and the other is that they are all bacterial the community that lives on the roots of these plants and on these supports or gravel or sand, which is like a supporting layer for these plants. That is to say, we have two systems and if we screw it up, then the device itself it cannot work. That is to say, the key is this pre- cleaning, so that at least these mechanical particles remove and then that we have a large enough device that can successfully works. And one more thing about these things is that you also have to be aware that if we install such a device in areas where it is usually lower temperature, we also need a larger surface area.
Because when the temperature drops, the activity of microorganisms also drops and the cleaning efficiency drops. Unfortunately, not everyone can afford such a plant- based cleaning device, because where we have houses next to each other, it is said to have even rows the houses where they are, we don't have room for a plant breeding device, at that time it is necessary to reach for these, I will say, prefabricated, small ones communal heating devices, which are intended for houses and used in order to have enough workers in activated sludge, air intake through of compressors, that is, the introduction of acid, for the action of these microorganisms we supply with oxygen and in this way speed up the operation and also we need smaller areas for equivalent wastewater treatment. However, we can always upgrade all these devices with this gift box, at least one part of, let's say, this biological purification device or plant greeting devices can still be applied to such greetings devices with activated sludge. Thank you for your attention and friendship.