Proposal to reduce potable water consumption in a metallurgical industry in the metropolitan region of curitiba city – case study

The research is based on the need to reduce the consumption of potable water. Due to the current water scenario allied to the company ’ s socio-environmental situation. The metallurgical industry is part of the third group with the highest consumption of potable water, the study described in this article can be used in other segments besides residences, public and private works. Currently, the water usage scenario of Curitiba and the metropolitan region is classi ﬁ ed as ‘ quantitative critical ’ , which can cause companies to accelerate the process of water collection through alternative sources. Through surveying potential sources for water collection, 3 sources of capture and 1 point for press water were classi ﬁ ed. For validation of these potentials, chemical-physical tests were performed on the water samples. Subsequently, the reservoir sizing calculations were performed based on the ABNT NBR 15527 standard. Thus, the initial value idea of reducing the potable water consumption of up to 84% even in the month with the lowest volume of rain.


INTRODUCTION
The population growth brings an increase in water consumption and decreases the quality of the sources. So, it contributes even more to an urban supply deficit (Teixeira et al. 2016). The United Nations (UN) considers potable water as a finite and fragile resource that is always pressured due to population growth, agricultural and industrial activities. It signals a water deficit in the coming years. If there is no drastic reduction until 2030, we may have a deficit of 40% in the potable water.
So, it is estimated that demand for the supply of potable water in industry between 2000 and 2050 will grow about 400% (UNO 2015). It is notable that the lack of water directly impacts the homes and industry. Otherwise, Conama resolution n. 357/2005357/ (Brazil 2005 provides in case scarcity supply to industries can be suspended, prioritizing residential supply. The lack of water is a known problem in some Brazilian regions. Long to attenuate the high consumption, the rain capture has been one of the alternatives encouraged by the governments of some countries (Lee et al. 2016). Some specific initiatives and several studies are done and published annually, but the theme focused on the industry is still somewhat widespread (Thomé et al. 2019).
The capture of rainwater can contribute greatly to the increase in the availability of water for consumption of the population. Also, the collection of rainwater is not something new, it is millenary and has been improving more and more (Campisano et al. 2017). Among these, the research leads to the reuse and importance of rainwater. Beyond that, the studies were initiated by analyzing the distribution of potable water consumption in Brazil, with the main focus on the region of Curitiba metropolitan region. Justifying the research in the databases of ANA (National Water Agency) and Sanepar were so important.

OBJECTIVE
The objective of this paper is to reduce (reduce by at least 30%) the consumption of potable water used for non-potable purposes through the capture, storage, distribution and application of water from alternative sources in non-potable production processes. Thus, to increase the availability of drinking water in the public potable network more directly, benefiting local residents and indirectly the city's population as a whole. Also promoting a reduction in the risk of stoppage in industrial activity due to the lack of this resource.

BIBLIOGRAPHIC REVIEW
In this chapter, all the content that allowed the understanding of the history of water abstraction and the science involved in the water cycle was addressed. This served as the basis for the construction of the research, a passage covering different levels, between definitions of water and its importance, abstraction history of rainwater, calculation method for reservoirs, legislation and other related topics.

Water
The planet Earth is mostly composed of water that is found in different types of states being, liquid, solid, and gaseous. Water is a fundamental resource for life on Earth also it is a resource found in nature in abundance. It has always been exploited without any concerns about its scarcity. As far as it is present in all living beings it is indispensable for life on our planet, it is, therefore, a vital resource for all living beings. Such as the human being who can have up to 60% of his weight composed of water, in plants reaches up to 90% of his weight, and in certain aquatic beings this number reaches up to 98% (Bassoi & Menegon 2014). Approximately 75% of the surface on planet Earth is composed of water, so is it possible to talk about water scarcity? However, we cannot say that water will end up on our planet because water being a chemical element has mass and is attracted by the force of gravity existing on our planet. The water on our planet is constantly moving. The amount is invariable for thousands of years, due to the hydrological cycle (Bassoi & Menegon 2014).
The 'Chuá de Educação Sanitária e Ambiental' (BRAZIL) program of the Minas Gerais Sanitation Company classifies freshwater and saltwater. Fresh water represents 2.5% of the planet's total water, with 70% of this water in glaciers and the rest in rivers, lakes, and underground sheets, and saltwater represents 97.5% of our planet's water volume being present in the oceans, which cover about 75% of the Earth's surface. The population growth brings an increase in the demand for potable water, and with this comes the need to seek sustainable practices to optimize water resources (COPASA 2012).

Importance of water
Potable water is essential for maintaining life on planet Earth. It is intrinsically linked to the health and even the dignity of the human being. Water is responsible for the climate variation and maintenance of rivers, lakes, and oceans. It provides the conditions for the development of plants and animals, thus reinforcing its concept of the essential resource for life, is also a good source of energy for hydroelectric plants, essential for agriculture and in the industry has multiple applications (Ribeiro et al. 2017). Even if the world's water does not run out it turns, and the intense use and contamination of it are gradually raising the costs to make it potable. Thus, becoming an increasingly less accessible resource for the vast majority of the inhabitants of the land. Even today potable water is a resource difficult to access for some regions of our planet. According to the report of the United Nations Organization (ONU 2021) objective 6 of the 2030 development agenda advocates universal and equitable access to clean water and sanitation by 2030. Despite this objective, it's clear that the challenge the UN cites is that 3 out of 10 people do not have access to clean water, and more than 2 million live in countries with a very critical water level and about 4 million people experience a severe shortage of potable water for at least one month of the year. According to the data collected by the national water agency (ANA 2017), Brazil has about 12% of the world's surface freshwater reserves. Table below shows the size of Brazil's water reserve in comparison to other countries. (Table 1).
Although Brazil has an approximate reserve of 12% of the planet's freshwater, the natural distribution of this resource is not balanced, according to the report of the national water agency (ANA 2017) the Amazon region concentrates approximately 68% of the amount of water available and the other 32% are in unequal shape throughout the country. Below in the graph, you can see this distribution ( Figure 2).
A factor of great relevance is related to the quality of groundwater and surface water in Brazil. In general, the agricultural, livestock and industrial activity added to deforestation has contributed to poor water quality. In large centers and/or strong growth, the lack of water is already noticeable for several reasons such as organic and chemical waste, illegal diversion of water (theft), application of drinking water for non-potable purposes, as well as leaks and other problems arising from pollution and distribution network (Telles 2013).
In rural areas, water contamination by chemical factors resulting from the vast use of pesticides is very common. The drought factor for example also makes intervention necessary so that the supply system does not collapse, this intervention is known as the 'caster system' and with it, it is possible to minimize the total lack of water in each period. In rural areas, the water is contaminated by chemical factors which results from the vast use of pesticides. The drought factor, for example, also makes an intervention necessary. So, the supply system does not collapse, this intervention is known as the 'caster system' and with it, it is possible to minimize the total lack of water in each period. The use of water for human supply has different proportions. Highlighting the fact that industrialized countries use more for personal hygiene and toilet flushing (Telles 2013). In Brazil the personal hygiene and toilet flushing are also presented, but with very different proportions.  The water cycle on our planet is also known as the hydrological cycle, water is in constant movement, this is a global phenomenon of closed circulation composed of several processes by which water starts its journey going from one stage to another, such as it is always in transition, it goes through different states, (solid, liquid and gas) (Miranda et al. 2011). Both urbanization and industrialization added to deforestation strongly contribute to the change in land cover that later affects the hydrological cycle. Soil heterogeneity plus climate change also directly impact river discharges at a global level, several hydrological phenomena need to be further studied in order to discover the present and future impact caused by these variations (Gayathri et al. 2015).

Brief history of the use of rainwater
Currently, the issue of rainwater use has been widespread, but the use of this water is a very old technique, as it is an essential asset for life and human development, it must always be seen as a priority in society precisely because it directly impacts the social environment, economic and cultural. History portrays that man seeks to increase the availability of this fundamental resource for life since antiquity (Dornelles 2012).
The use of rainwater is a technique developed so that people have a greater amount of water available in a way that is more accessible to everyone. Water encompasses not only the sphere of essential resources for life, but also the social, economic and cultural sphere, given its importance. History reports that for many years man has been looking for ways to ensure that water is always available in abundance, especially in areas with less availability of this resource, such as in arid and semi-arid regions (Tomaz 2011).
It is not known for sure how old the first initiatives focused on rainwater storage are, but according to Dornelles (2012) there are records of structures developed with the same purpose dating back to 3,000 BC. It reinforces the concept that this is an old technique, Tomaz (2011) mentions that in 830 BC a Moab stone was found in the region of Moab, near Israel, which already contained the King's determination that each house would need to have a cistern to store rainwater. The stone with the deed is shown in the figure below ( Figure 3).

THE COMPANY UNDERSTUDY
The company is among the 3 world leaders in the production of automotive and industrial bearings and has 100 years of experience, the company is present and innovating in the industrial, automotive, and aerospace markets. Manufacturer of high precision equipment that does business all over the world in bearings and other products also with ecological awareness that decrease energy consumption and reduce friction. Based on innovation and commitment, the company has been building its development history, designing products with high quality and technology. It currently has about 25,000 employees, Water Supply Vol 00 No 0, 4 Uncorrected Proof located in more than 70 factories, 7 R&D centers, and more than 100 commercial offices worldwide. In addition to providing services, the Group designs, develops and manufactures bearings, linear guides, bearings, and automotive spare parts.

Company location
The company is located in the metropolitan region of Curitiba, specifically in the industrial region of Fazenda Rio Grande. The land area is approximately 50,000 m² and it is within this perimeter that opportunities for water collection points have been identified. In general, we have an approximate area of 44% of the non-permeable area and 56% permeable area. In the figure below, it is possible to better visualize these areas. (Figure 3).
In the figure above, it is possible to visualize the non-permeable area (without marking) and the permeable area highlighted in orange.

Water scenery in Curitiba and the metropolitan region
Based on the water consumption scenario of the country we can estimate that 85% is concentrated in the first 3 items of Table 3. With the industry among the 3 main extractors of drinking water. Exploring more closely the points of consumption and directing the research to the Curitiba metropolitan region. More specifically to the municipality of Fazenda Rio Grande, where the company in question is located. The interactive map of the national water agency (ANA) demonstrates through the qualitative and quantitative balance sheet that Curitiba and the metropolitan region are classified as 'Quali-quantitative Criticality'. This qualification is given due to the high demand (withdrawal) and a large amount of organic cargo thrown to the rivers. In Figure 4 below we can note the selection of the municipality of Fazenda Rio Grande in red.
In Figure 5 above, in detail the exact location of the municipality of Fazenda Rio Grande in the red area, this red area symbolizes the region that is classified as qualitative and quantitative criticality. In this way, it can be seen that the region's scenario requires alternatives to mitigate scarcity since the municipality continues to grow and soon the demand for water will also grow with this development.

Volume of water used by the company
The company currently makes all water withdrawals from the public supply network, and it does not have an artesian well, and does not take advantage of rainwater. All effluent is sent to a certified company that treats liquids within current effluent treatment standards. Currently, consumption varies between 506 and 512 m 3 months as shown in Figure 6 below performed with the average of the last 4 years 2016 to 2020.
According to the Figure 6, even in the holiday period, the volume does not have much oscillation of consumption because the teams take over and it is a favorable period for maintenance and cleaning of the factory. Currently, the company depends on 100% of the water supply coming from Sanepar. The analysis of the current flow of water distribution showed that the potable water network can be easily isolated for the use of rainwater for low-cost non-potable purposes. This since the water extensions are distributed across sectors and are also properly identified. The current stream can be seen below. (Figure 7).

Uncorrected Proof
It is notable that potable water is used in all processes of the company including the 4 main points of consumption that do not require the use of potable water. Before moving to the liquid center this water receives treatment and additives specific to the process.

METHOD
The work methodology covered 3 main points: The research of scientific articles related to the subject, the verification of the company's processes and the quantification of the volumes of water consumed for non-drinking purposes and the testing with qualitative and quantitative analysis of the water collected through alternative sources. The flowchart below explains the research, which was taken in 14 months to complete and the practical part of simulation and sample testing took another 12 months. Basically, the work cycle can be seen below. (Figure 8).
The research was carried out using data provided by the National Water Agency (ANA) and the Sanitation Company of Paraná (Sanepar). It intends to understand more about water consumption, availability and the need to develop new forms of water collection in this region, which could be seen through dynamic maps. The research based on the platforms: Capes, Scopus, Web of Science direct, SciELO, Engineering village provided several examples of rainwater collection and use.

Rainfall volume of the region
The Fazenda Rio Grande region's rainfall volume is 1,406.2 mm per year. Average calculated in the period from 1977 to 2006 the data originate from the Mandirituba rainfall station (ANA code 02549062) Graph presents this historical volume. (Figure 9).
The rainfall data of the region are of great relevance because only with this information that can be calculated is the volume of the cistern and allows us to better understand the scenario of the region where the company is located.

Location of collection points
For a better understanding of the points and organization of the work and field research, the points initially identified as a potential source were located on the company photo, these are identified with numerals from 1 to 4 presented below. (Figure 7).

Uncorrected Proof
The 4 collection points previously identified in chapter 3 were; (1) drainage channels, (2) ditch water, (3) climate control water, (4) shutter (convergence point of all rainwater). These points were verified by the environmental department team, where there was a consensus for their validation as potential sources of capture.

Quantification of volumes per proposed point
Through consensus on the collection points among those involved in the project, definitions were started on the method and period of monitoring of each identified potential source. At this point in the research, it was necessary to effectively show the potential volumes of water, and as it was, at that time, a survey based on estimates, its volume was quantified using various techniques and equipment such as; reservoir sizing simulations according to ABNT NBR 15.527, water tank installations with graduation, and/or hydrometer installations.

Drainage channel
Since its conception, the drainage channel had the sole purpose of directing water to the park behind the company, avoiding flooding of the neighboring company in case of torrential rain, it became a rainwater catchment point. For the validation of this point, a DJI Air 2S model drone was used, together with the DroneDeploy ® application to obtain a specific manual flight plan for carrying out topography, as it is a new model of drone, the software does not support fully autonomous flight. The topography reveals the position of the current channel favors the capture of water and also allows us to apply a 100 m 3 reservoir for water storage that will be directed by gravity without the need to install pumps to pressurize water from the channel to the cistern. In detail, the green dot in the figure below shows the location of this reservoir. (Figure 5)

Industrial air conditioner water
After a year of monitoring the volume of water generated by the condensation process, it demonstrated a great variation due to the various conditions of temperature and humidity. Also, the factory activity itself demands more or less heat exchange contributing or not to the increase in the volume of condensate. For this stage, a 3 m 3 water tank was installed and a hydrometer was installed at the outlet where the average daily volume measured was 1.5 m 3 . The condensed water has a high quality for use in non-potable purposes. So, that is required little or no treatment before its use, in this case, the analyses proved the security of the application of this water directly in the liquid plant 'water and oil' and the surplus goes to the shutter.

Drainage moat
The water from the drainage pit is pumped into the rainwater net, this by having a good quality water feature for non-potable purposes. So, it is going to be directed to the shutter to be pumped into the rainwater reservoir. For better measurement a hydrometer was also installed in the outlet pipe, thus allowing better monitoring of its flow. The average volume measured was 3.07 m 3 day.

Sample collection and analysis
The collection and analysis of water are the main points of the work, since the quality of this water will enable its use not only in bathrooms and cleaning, but also in the production process. The treatment of water is also very relevant because, even when groomed, employees have a long period of exposure during their working hours.

Water collection
The collection of water was carried out using 2 bottles as directed by the laboratory. An extra 100 ml sample was collected in a sterile flask. The laboratory's recommendation is that the samples be collected and kept cool during transport, and the analysis should be done within 24 hours after collection. Below it is possible to observe the samples packed in a thermal bag, and around them ice sheets in gel. (Figure 10).
The samples were taken a few hours after collection and they were led to the analysis. The time to return the result is around 7 days as the DBO test already requires 5 days, in short, DBO corresponds to the necessary amount of oxygen so that, under aerobic conditions, there is oxidation of the biodegradable organic matter.

Water analysis results
Due to the convergence point of rainwater water from the drainage pit, the water from non-permeable areas, asphalt sidewalks, and roof the analyses and monitoring of water quality were removed from this point. At the collection time, which occurred after discarding 1 time of the volume retained in the shutter approximately 100 m 3 after the beginning of rain. Thus, it was possible to evaluate the water quality more assertively without having to isolate the sources of dosage later to treat the waters. Differently, if the result of the analysis demonstrated a need for more intensive water treatment, the results of the analysis can be seen in the table below. (Table 2). Observations: 1. The results presented in this report are limited to the sample received by LabQi -Environmental Analysis Laboratory. 2. The methods used in the assay are based on the methodology presented by APHA -Standard Methods for the Examination of Water and Wastewater, 22nd edition, 2012.

ND¼Not Detected
The results presented in the test show that the use of this water is safe as long as it is properly stored and treated following the Brazilian normative NBR 15527/2019. Through the research carried out throughout the work it was possible to determine the volumes of water consumption for non-potable purposes. This volume raised is described in Table 3 below.
With the data in the table above, it is evident that 84% of the monthly water consumed is used for non-drinking purposes. During this stage, the biggest challenge seemed to be the installation of water meters and it is clear that monthly monitoring requires a reasonable time given the distance between the measuring points.

Sizing of the water tank
About the reservoir sizing, the brazilian normative NBR15527 -2007 (ABNT 2007) was used as the basis for the sizing. This standard deals with the requirements of the use of urban cover waters for non-potable purposes and also presents six methods of sizing water reservoirs. When evaluating the results of the methods tested, the Neto Azevedo method (Equation (1)) was chosen for having returned a result closer to the reality of the company. The simulation method was also used and validated the results since the collection potential was higher than the company's demand. So, unfortunately, the methods presented in brazilian normative NBR15527 did not converge with each other, so they were not equivalent. As it does not have a clear formula to calculate the period of few spots of rain considered the rainy months below 100 mm, in the case 4 months (April, May, June, and August). So, these months are considered as a month of drought and/or little rain. Thus, the volume of rain is obtained by the following equation (Equation (1)):  Uncorrected Proof Pis the numerical value of the average annual precipitation (mm); Ais the numerical value of the collection area in projection (m2); Tis the value of the number of months of little rain or drought (month or months); Vis the numerical value of the usable water volume and the water volume of the reservoir (L). 0.042 -Standard loss coefficient used by the Azevedo Neto method.
The data for the application of the Azevedo Neto method and simulation are listed below in Table 4. The rain data is provided by the Brazilian Pluviometric Atlas (Pinto 2011).
To calculate the dimension of the reservoir, the rainfall data from the period 1977 to 2006 were used. Below the table lists the average volume per month within this period and the volume is presented in mm. (Table 5).
Soon applying the equation with the data in Tables 4 and 5 we have (Equation (2)); To perform the simulation method were used in the data in Tables 4 and 5, and the results can be seen in Table 6 below:  When we evaluate the numbers presented in this method, it is possible to identify that there is no need to supply water from the public supply network. Even in the lower rain month, in the case of June, the reservoir will be connected to the public network. This is because of some contamination or atypical period of drought it will need to receive water from the public network. After all, the pipe of the toilets, external cleaning taps, and alpine tower will be connected directly to this reservoir, no longer to the potable water tank.

Proposal of the new flow of distribution
To define the new water distribution flow, it was necessary to first evaluate the volume of capture in power and also to analyze the chemical-physical characteristics of the collected samples. With the results in hands, it was and according to the guidelines of the Curitiba Law (Law10,785 of September 18, 2003), the municipal law of Fazenda Rio Grande (Law No. 1.365/ 2020 DE 27 January 2020), it was possible to define the new flow according to Figure 11 below that contains in detail the identifications of 'A' to 'E' for a better understanding of the functioning, below figure. (Figure 12).
Based on quantitative and qualitative data raised, the new distribution flow provides the transformation of the current reservoir of drinking water with a capacity of 600 m 3 (detail 'E') into a reservoir for water storage non-potable. And, the water coming from the conditioner is stored in a reservoir with a capacity of 3 m 3 (detail 'B'). Which drainage pit and rain were damned on the shutter (detail 'C') also recounting the reservoir of the drainage chute with a capacity of 100 m 3 (detail 'D'). The treatment will be carried out with particulate and chlorine filters according to the Brazilian normative NBR 15527/2007. The current hydraulic internal distribution network greatly favors this transformation. The points of water potable scans are very close and located only in one region of the shed, which means it is very easy to dismember from the new network of water non-potable. Towards water drinking machine thinking of a doubled capacity compared to the consumption of the month, is pre-visa the acquisition of a new reservoir with a capacity of 200 m 3 (detail 'A') exclusive to water drinking water, this reservoir may complement the non drinkable water in face of some scenario of long periods of drought. Even in that period, the system will still have the capture of the water from the conditioner and the drainage gap that rotates around 4.5 m 3 per day.

CONCLUSIONS
The main objective of the work was achieved because the results of the analysis carried out during the research have enabled the design of a new flow for the collection and distribution of non-drinking water. Thus reducing the consumption of drinking water by up to 84%, a much higher volume to the proposed by the group, which is 30%, even with a potential to replace 100% of the water demand, the 16% are intended for human consumption where it requires a broad normative study and a specific treatment for potabilization. So, this work does not lead to this volume destined for human consumption remaining as a recommendation for future work. Currently, we are still using water from the ditch and the climate control system for general cleaning, and these two sources alone provide around 133 m 3 , equivalent to 26% of the current volume consumed by the company, and only 4% below the volume The reduction requirement proposed by the group, however, as it is a manual supply and with an adapted distribution, it is not possible to make an integral and systemic use of this volume. Through the interactive maps of the national water agency (ANA) it was possible to conclude that the condition of Curitiba and the metropolitan region requires new sources of water collection to avoid greater rationing. Which now takes place on some weekends throughout the year. The conditions of the current hydrographic basins do not keep up with this growth in the region, both residential and industrial, therefore, based on this evidence, the work went from just a vision of the group in the environmental issue to a vital need for the company's operation in the midst of this scenario of water scarcity.
Even knowing that there are some challenges for these captures, including the technical part, as we do not have control over the climate, we can have a large volume of precipitation in a small period of time where the accumulation of 100 m 3 provided by the shutter may not be fully utilized depending on the pumping capacity, to minimize this loss of volume. So, Uncorrected Proof the dammed water in the reservoir of the drainage channels was added to the water from the ditch and climate control, and it will contribute to the composition of the non-potable volume.
The convergence of facts and data studied, together with the environmental visions of large business groups, validates the global concern of public and private entities related to the conservation, preservation and conscientious use of this vital resource for human survival on Earth.

DATA AVAILABILITY STATEMENT
All relevant data are included in the paper or its Supplementary Information.