Water Sci Technol 1 September ; 80 5 : — A complete 2 3 factorial design was performed for the variables time, pH and current. The electrochemical production of free chlorine species followed by subsequent photolysis and production of radical species can convert a simple electrochemical process into an advanced oxidation process AOP. By , the milk industry was in sixth place with an annual production of just over 26 billion litres Anualpec Dairy effluent treatments include the application of physicochemical and biological methods, with the specific objective of reducing the volume of the sludge produced Demirel et al. Physicochemical processes are effective in the removal of emulsified compounds; however, the addition of reagents increases the costs and the removal of COD is low.
|Published (Last):||1 July 2012|
|PDF File Size:||17.99 Mb|
|ePub File Size:||4.28 Mb|
|Price:||Free* [*Free Regsitration Required]|
Integrated modeling of water quantity and quality in the Araguari River basin, Brazil. Corresponding author: Marcio Ricardo Salla mrsalla feciv. The Araguari River basin has a huge water resource potential. However, population and industrial growth have generated numerous private and collective conflicts of interest in the multiple uses of water, resulting in the need for integrated management of water quantity and quality at the basin scale.
The water balance performed by the SIMGES module for the period of October to September provided a good representation of the reality of this basin. The parameters studied were dissolved oxygen, biochemical oxygen demand, organic nitrogen, ammonia, nitrate and total phosphorus.
The coefficients of biochemical reactions, sedimentation rates and sediment dissolved oxygen release for this period were calibrated and validated in the quality modeling using the GESCAL module. A sensitivity analysis indicated that the coefficients of carbonaceous matter decomposition, nitrification, water temperature, and sediment oxygen demand interfered more significantly in the variables of state. To prevent eutrophication in the Nova Ponte reservoir and in the other cascade reservoirs, the local River Basin Committee should adopt restrictive actions against the use of agricultural fertilizers.
In developing countries, such as Brazil, which lack financial resources for basic sanitation and proper wastewater treatment, the problem of dissolved oxygen consumption in waterways after wastewater has been discharged into them is still significant, justifying the use of the assimilative capacity of waterways to complement the treatment process.
Sustainable development and rational water use require the existence of a proper relationship between water quantity and quality. In this context, joint mathematical modeling allows for the diagnosis and prediction of impacts resulting from multiple water uses and the discharge of pollutant loads.
Numerous researchers have designed a variety of models and Decision Support Systems DSS that are useful for water resource planning and management at the basin scale. It is well known that the main focus of computational tools is quantitative water resource management and planning, considering the increasing demands and need to implement optimal rules for the operation of water resources.
However, environmental concerns regarding water quality at the basin scale, driven by the continuous discharge of domestic and industrial wastewater, have led to the design of increasingly complete water quality models De Paula, Several other models have been designed with increasing complexity and number of modeled variables. Those models can be used to simulate different water quality problems.
This brief review reveals the marked existence of river and reservoir water quality models that are not linked with any DSS in the quantitative management and planning of water resources. According to Paredes-Arquiola et al. Due to this situation, many researchers around the world, e.
According to the State Environmental Foundation, the state of Minas Gerais has the highest water resource potential in Brazil and accounts for the generation of Nevertheless, there is a lack of scientific research on the integrated management of water quantity and quality at the basin scale. Many water resource management proposals have been put forward by local river basin committees.
However, these proposals are not underpinned by integrated studies of water quantity and quality in lentic and lotic environments, but instead focused only on the implementation of quantitative and qualitative telemetric information systems, on user registration and updating, on the creation of criteria for granting water rights, on charging for the use of water and on payment to the surrounding municipalities, watercourse guidelines, conflict prognosis between demands and capacities, and the creation of environmental protection units.
The calibration and validation of the biochemical reaction coefficients, sedimentation rates and sediment oxygen demand will serve as a basis for future studies on quantitative or qualitative interventions in this basin.
The coefficients that are part of the natural self-purification process of a watercourse, be it lentic or lotic, have distinct influences on the final water quality in the water system. Thus, using the factor model, this study performed a sensitivity analysis of the four main coefficients of biochemical reactions involved in the modeling the re-aeration coefficient K a , decomposition coefficient of CBOD K a , coefficient of decomposition of organic nitrogen KN oa , and coefficient of ammonia nitrification KN ai , of the water temperature Temp and the sediment oxygen demand S OD.
There are few computational tools or models that simulate water quality linked to quantity at a basin scale. Andreu et al. Thus, hypothetically considering a basin with multiple and transient uses, water quality can be simulated for any simulated outfall, recharge and environmental flow scenario. In this water balance was considered the flow in rivers and reservoirs at the basin scale, based on the spatial and quantitative definition of outfalls point wise outfall for irrigation, industries and human consumption.
Simulations were performed by means of a network flow optimization algorithm, which controls the surface flow within the basin while aiming to minimize the deficits and maximize the liquid levels in reservoirs to meet irrigation, human consumption and hydropower demands.
In order to simulate water quality linked to quantitative management in lentic and lotic environments previously defined in the SIMGES module, Paredes-Arquiola et al. Although GESCAL allows modeling eutrophication, temperature, toxics and conventional contaminants, in our case, due to the lack of data and planning purpose of the study, the contaminants modeled were DO, CBOD, organic nitrogen, ammonia, nitrate and total phosphorus.
In the modeling process adopted in this study, the relationship between nitrogen cycle and carbonaceous organic matter and the effect on dissolved oxygen, and total phosphorus as an arbitrary parameter was considered, according to the scheme illustrated in Fig.
Figure 1. Relationship among the modeled quality parameters. Study area: Araguari river basin. The Araguari River basin Fig. This basin covers an area of approximately 22, km 2 , with altitudes ranging from m to 1, m and rainfall exceeding mm year The weather condition is warm, with the dry season between May and September and a wet season between October and April Rosa et al.
It has a resident population of approximately 1. According to the IGAM, surface and groundwater demands allocated in for human consumption, irrigation, industry, and livestock watering were Figure 2.
This basin has six hydroelectric power stations HP , the four largest ones located on the Araguari River with cascade reservoirs Fig. However, in the period they had not yet entered into production that, for modeling purpose, make us to consider this region as a simple river segment. In the s, the joint effect of economic valuation of soybeans and the scientific discovery of suitability of the crop to the soil of the Araguari River, transformed the region through the practice of a modern agriculture, associated with the intensive use of phosphate fertilizers and agrochemicals.
Also, the presence of phosphate rocks in the region contributes to the existence of that nutrient from their natural deposits EPE, ; Rosolen et al. Figure 2 shows that the basin may be divided into 18 sub basins, whose main economic activities are agriculture, aquaculture, farming, mining, power generation, manufacturing, agribusiness and tourism. The initial procedure in the quantity modeling was to outline the topology of the model using AQUATOOL, which basically corresponds to the situational diagram of the Araguari River basin, including the unscaled elements of the model, as illustrated in Figure 3.
To improve visualization, the elements that represent the smaller tributaries and the diffuse distribution along the Quebra-Anzol, Araguari and Uberabinha rivers were removed from Figure 3. Figure 3. Model topology applied to the Araguari River basin. In the quantity and quality modeling processes, the three main watercourses of this basin Araguari, Quebra-Anzol and Uberabinha rivers were divided into 20 segments, each of which was identified by a numbered node upstream and another numbered node downstream Fig.
According to Figure 3 , all the tributaries and point wise discharges of domestic wastewater with and without the wastewater treatment plant WWTP are identified as inputs. The quantity data of the upper Araguari River and upper Quebra-Anzol River were used directly as input data in the simulation.
However, the diffuse and point wise inputs from the other tributaries were obtained from the specific outfall in m 3 s -1 km -2 Eq.
Existing data for the upper Uberabinha River were used directly as input data in the simulation of the model. The absence of water flow data from the mouth of this sub basin and from the two small hydroelectric plants precluded the use of the specific discharge method to estimate the diffuse and point wise flow rates. Thereby a specific rainfall-runoff model is needed for the water balance in this sub basin. This is a distributed model widely accepted worldwide due to the reduced number of parameters and their relationship with the physical characteristics of the basin Tucci, ; Rezende, This is a semi-distributed model that is part of a range of models which use the most important surface runoff processes by means of a simple structure and with a reduced number of parameters.
To this end, the results of the time series of surface flow obtained from the HBV model were compared with the existing time series of surface flow in the upper Uberabinha River. Each assessment of the objective function implies the execution of the HBV model. This algorithm has been used successfully to solve nonlinear problems in various applications of hydrological models at the basin scale Paredes-Arquiola et al.
In our study, the model was applied to the sub basin corresponding to the single water flow monitoring station existing in the upper Uberabinha River Fig. Due to the similarity of climate, geology, land use and occupation throughout the Uberabinha River sub basin, the initially calibrated parameters for this sub basin were used as input data to estimate the surface flow into the other rural sub basins.
As it can be seen in Fig. Point wise demand with and without consumption. The data on granted and georeferenced surface water demands for human consumption, irrigation, industry, and livestock watering were obtained from the IGAM, based on data.
The water balance was determined using the SIMGES module after completion of the topographic map, along with inputs of quantity data required for each element of the model, which include the point wise surface consumption demands, point wise requirements for hydroelectric purposes without consumption, point wise entries of tributaries, point wise effluents with and without WWTP, and the diffuse inputs from the main rivers Quebra-Anzol, Araguari and Uberabinha.
Various input data on storage reservoirs and hydroelectric plants are also essential in modeling, such as the dead volume of each reservoir hm 3 , volume set aside in each reservoir at the beginning of the simulation hm 3 , maximum storage capacity in each reservoir hm 3 , base depth m , minimum turbine depth m , energy coefficient GW hm 3 m -1 , maximum turbine requirement m 3 s -1 , evapo-transpiration for each month, and bathymetric data of the reservoirs.
Another text file was created containing data on the water quality of tributaries and point wise discharges of WWTP treated and untreated domestic wastewater.
Likewise, the per capita gross pollutant loads of organic nitrogen, ammonia, nitrate, and inorganic and organic phosphorus were estimated, to be 8.
These estimates are based on the numerous experimental results reported by several authors, such as Tchobanoglous et al. The simulated water quality parameters are: dissolved oxygen, biochemical oxygen demand BOD 5 , organic nitrogen, ammonia, nitrate and total phosphorus. Due to the absence of eutrophication in the reservoirs for the time series under study, the modeling of water quality assumed thoroughly mixed reservoirs, for which the simulations were performed adopting only the upper region of the epilimnion.
Although we thought that the behavior of the water quality in the reservoirs are enough defined with the model, overall, based on the available data, new information regarding temperature profiles and dynamics of nutrients could improve the model of the reservoir. Generally, the model is related to phosphorous and the internal sediment source of phosphorous. In this case, the developed CSTR model could be incremented to two layer model and could include the effect of the sediment, improving the knowledge of the system and the robustness of the model.
This plot shows the longitudinal distance between all the elements of the model, the longitudinal distance of the 20 river segments, and the location of the water quality monitoring stations used in the calibration model and its validation process.
To calibrate the model in each segment of the river, existing water quality data was used in the node downstream from the segment Figs. The Covar method empirical equations that depend on the mean flow velocity and the net depth showed a good fit between observed and simulated dissolved oxygen data only in the headwater segments of the rivers involved. Table 1 identifies the 20 segments, the longitudinal length of each segment, and the hydraulic relationships used in the headwater segments.
Figure 4. Single line diagram of the model. Table 1. Identification of the 20 segments, longitudinal length L of each segment, and hydraulic relationships used in the headwater segments. Calibration, validation and sensitivity analysis. In this study, the coefficients of biochemical reactions, sedimentation rates and sediment oxygen release in the 20 segments identified in Figures 3 and 4 were calibrated through a process of trial and error.
A sensitivity analysis was performed of all the segments defined in Figures 3 and 4 in view of the changes in the input values of the four main previously calibrated coefficients of reactions re-aeration coefficient K a , coefficient of carbonaceous organic matter decomposition K d , decomposition coefficient of organic nitrogen KN oa , and coefficient of ammonia nitrification of KN ai , sediment oxygen demand S OD and water temperature Temp.
Unlike what was done in the calibration process, in which each segment was calibrated separately, using the data observed in the node downstream from the segment as the base for calibration, the sensitivity analysis joined two or more sequential segments in some cases in which the simulated and calibrated values of the node downstream from the last sequential segment were used as the standard in the analyses.
The analyses of sequential segments were organized as follows: Araguari segments 1 , 2 , , and correspond, respectively, to the nodes 2, 3, 7, 9 and 12; Quebra-Anzol segments 1 and correspond, respectively, to the nodes 18 and 3; finally, Uberabinha segments 1 , and 4 correspond, respectively, to the nodes 19, 21 and According to Loucks et al.
Figure 5a illustrates the variation of simulated flow during the period of calibration and validation of the main sections in the basin. The flow at the mouth of Uberabinha River varies from Figure 5. Downstream to the Nova Ponte reservoir, the box-plot graph Fig. Figure 6.
Blog Neo Ambiente
We'd like to understand how you use our websites in order to improve them. Register your interest. The nonparametric test of Kruskal—Wallis and relative risk were used to evaluate surface water quality allowed to an identification of the most degraded water bodies in Piracicaba River and Paraopeba River basins, two important hydrographic basins in Brazil. Total manganese, dissolved iron, and fecal contamination indicator were considered the most relevant parameters for the characterization of water quality in the basins. The analysis of violations and the relative risk confirmed that both basins are subject to impacts resulting from economic activities. On comparing the relative risks, the Paraopeba River basin showed a higher risk of violation for 5-day biological oxygen demand BOD 5 , total manganese, total phosphorus, total suspended solids, and turbidity, while the Piracicaba River basin showed a higher risk of violation for fecal contamination indicator.
The information in this preliminary pricing supplement is not complete and may be changed. This preliminary pricing supplement is not an offer to sell nor does it seek an offer to buy these securities in any jurisdiction where the offer or sale is not permitted. Subject to completion dated October 23, Investing in the notes involves a number of risks.