1 Water Pollution

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1 Water Pollution

  1. 1. WATER POLLUTION 1. Introduction. 1.1. Need for water. 1.2. Location of water. 1.3. Hydrologic cycle. 2. Fresh water composition. 3. Fresh water pollution. 4. Natural regeneration. 5. Parameters determining water’s characteristics. 5.1. Physical parameters. 5.2. Chemicals Parameters. 5.3. Other parameters. 6. Legislation. 6.1. European Charter on Water Resources. 6.2. Spanish Legislation. 6.3. European Legislation. 7. Wastewater treatment. 7.1. Introduction. 7.2. Preliminary treatment. 7.3. Primary treatments. 7.4. Secondary treatments. 1
  2. 2. 7.5. Tertiary treatments. 7.6. Effluent disinfection. 8. Sludge treatment. 8.1. Introduction. 8.2. Concentration. 8.3. Stabilization. 8.4. Mechanical dewatering 8.5. Heat drying. 8.6. Final disposal. 9. Examples of urban wastewater treatment 2
  3. 3. 1. Introduction. The four basic natural resources are water, air, land and energy. We need water for multiple uses and a certain quality is required. Its use leads to the generation of wastewater that can cause an impact on the environment. Water scarcity and pollution has become of most importance in recent years. In this chapter we’ll discuss both fresh water and wastewater treatment, either for reuse or disposal in the environment "without polluting it" 1.1 Need for water. The use of water could be classified in order of importance as shown in Table 1. Table 1. Water use. Needs WORLD WIDE % EUROPE % Agriculture 66 30 Industry 24 14 Urban 8 18 Others (refrigeration, energy, 2 38 recreational, etc.) Let's see some examples of the order of magnitude of water consumption: Agriculture. In Spain, water consumption in agriculture makes up 80%, although with modern techniques of drip irrigation, significant savings could be achieved. For example, to produce 1 metric ton of maize 1,000 metric tons of water are needed. 3
  4. 4. Industry. The applications of water in industry are numerous. For example, to produce 1 ton of paper requires 25 metric tons of water and a tanning factory consumes over 20 L of water per kilo of raw material Domestic uses. In Spain each habitant consumes between 200 and 300 liters. An American consumes about 340 litres per day. As we can see, needs for water at home are minimal when compared to the overall amount required by man to cover all their needs. Information about water use in Europe can be found at http://www.grid.unep.ch/product/publication/freshwater_europe/consumption.php 1.2 Location of water. Water is one of the most abundant substances in nature. It is found in: Living beings, as the main constituent. In most foods. On Earth. Water covers nearly three quarters of the earth's surface, with a total volume of about 1,360 106 km3. It is distributed as shown in Table 2: 4
  5. 5. Table 2. Water inventory. Reservoir Volume (cubic km Percent of Total x 1,000,000) Oceans 1,370 97.25 Ice Caps and Glaciers 29 2.05 Groundwater 9.5 0.68 Lakes 0.125 0.01 Soil Moisture 0.065 0.005 Atmosphere 0.013 0.001 Streams and Rivers 0.0017 0.0001 Biosphere 0.0006 0.00004 This could be a pessimistic inventory of available water, given that nearly 98% is sea water, and, almost 80% of the rest is ice. However, this is not a real picture because the water available for consumption is renewed through the water cycle. 1.3 Hydrologic cycle. Hydrologic cycle is the process by which the amount of water existing on earth remains constant and is due to the constant exchange of water that takes place between the earth's surface and atmosphere. 5
  6. 6. The hydrologic cycle is a conceptual model that describes the storage and movement of water between the biosphere, atmosphere, lithosphere, (Figure 1), and the hydrosphere. Water on this planet can be stored in any one of the following reservoirs: atmosphere, oceans, lakes, rivers, soils, glaciers, snowfields, and groundwater. Figure 1. Hydrologic cycle. 6
  7. 7. Table 3. Typical residence times of water found in various reservoirs. Reservoir Average Residence Time Glaciers 20 to 100 years Seasonal Snow Cover 2 to 6 months Soil Moisture 1 to 2 months Groundwater: Shallow 100 to 200 years Groundwater: Deep 10,000 years Lakes 50 to 100 years Rivers 2 to 6 months 2. Fresh water composition. Fresh water is not pure because of its high power as solvent. Thus, it contains dissolved gases, suspended solids and dissolved solids. These compounds are incorporated during its fall as rain and during its percolation through the soil. In addition, water also incorporates microorganisms from air and soil. Thus, groundwater presents a very high degree of mineralization, as opposed to surface water. Table 3 compares the characteristics of groundwater and surface. Table 4. Characteristics of surface and groundwater 7
  8. 8. Characteristics surface water groundwater Minerals Low High Dissolved oxygen Saturated Low Hydrogen sulphide Absent May be present Colour Present Not present Turbidity Present Not present Iron and manganese Unusual Frequent Organic Compounds Variable Variable Pollution Frequent Unusual 3. Fresh water pollution. Fresh water pollution is caused by the discharges of toxic substances coming from domestic, industrial and agricultural uses. Water pollutants are classified as: • Biodegradable Organic Substances. These are substances that oxidize in the presence of oxygen due to bacterial activity. As a result, there is a decrease in the concentration of dissolved oxygen, which causes: Adverse effects on aquatic life. Presence of bad odours. • Nutrients. These are essential chemical elements for the growth of life. In addition to carbon N, P, S, K, Ca, Fe, Mn, Co B are also needed. Nutrients become pollutants when their concentrations are so high that they allow excessive growth of aquatic plants, mainly algae. This process is called eutrophication and is mainly due to an increase in phosphorus. • Pathogens. Those organisms able to produce diseases. 8
  9. 9. Examples of pathogens associated with water are viruses, bacteria, protozoa and helminths. • Salinity. The amount of dissolved salts limits the possible uses of water. It is normally due to the presence of chloride. Water is brackish when chloride content is greater than 5,000 ppm. Chloride content in drinking water must be less than 500 ppm. • Heavy metals. Among the heavy metals are: Al, As, Be, Bi, Cd, Zn, Co, Cu, Cr, Sn, Fe, Mn, Hg, Ni, Pb, Se, Tl, Ti. Some of them are nutrients for many animals and plants, but in greater concentrations they are toxic. One characteristic of metal pollution is its persistence in the environment. In addition, heavy metals concentrate along the food chain. • Minor organic compounds. These compounds are found in a lesser concentration and come from plastics, fuels, solvents, paints, pesticides, detergents, food additives, pharmaceuticals, etc. Usually these compounds are hardly biodegradable or non-biodegradable. • Radioactive substances. Produced during the production and use of uranium. However, some of the radioactive elements found in water are of natural origin. • Thermal pollution. It is due to the use of water as coolant in many industrial processes, when a large part of the water returned to its natural source returns several degrees warmer. Increment of temperature causes the following effects: Reduce oxygen solubility in water. Increase metabolic reactions speed. • Sediments. These are mixtures of mud, sand, organic matter and various minerals, that appear as a result of erosion and domestic and industrial discharges. Harmful effects of sediments are: Reduce the capacity of lakes and reservoirs. 9
  10. 10. Affect the bottom-dweller life. Produce turbidity. 4. Natural regeneration. When a discharge of domestic wastewater to a river occurs, microorganisms use organic material to obtain energy through oxidation with the dissolved oxygen in water (catabolism), as well as to construct cell-matter (anabolism). This will cause the elimination of organic matter and a reduction of O2 concentration in water. As available food sources diminish, the death of microorganisms and destruction of cell-material is produced. At the same time, oxygen concentration increases due to its diffusion from atmosphere. At the end of this process, downstream, the situation goes back to its initial state, through a natural regeneration process. However, the capacity for this natural regeneration is limited, so that wastewater should be treated before being discharged. 5. Parameters determining water’s characteristics. 5.1 Physical parameters. • Temperature. It is measured easily and is very important in order to assess the speed of biochemical reactions of organic matter decomposition, the solubility of gases or amplification of flavors and odours. • Color. It is due to the presence of organic and inorganic materials in water. True color is due to dissolved materials and apparent color is due to suspended materials. Color is usually measured by comparison with colored patterns. • Turbidity. Water is cloudy when it contains material or colloidal suspension. Turbidity can be determined by these methods: 10
  11. 11. a) Turbidimetry: Comparing the transmission of white light through the suspension and through a standarized solution. b) Nephelometry. Comparing the intensity of light scattered in the sample and in a reference dissolution. This method is broadly used and can be carried out continuously and is related to suspended solids. Figure 2. Equipment for turbidity determination. • Solids: Total solids refer to the residue remaining after a process of evaporation at 103-105 ° C. Solids can be classified according to different criteria: a) Depending on their nature. Organic. These are substances of animal or vegetal origin containing C, H and O, and they can be combined with N, S, P, etc. Major groups are proteins, carbohydrates and fats, together with its decomposition products. Also called volatile. Inorganic. These are inert substances not subject to degradation. There are fuel and ashes remaining at 550 ºC, although some salts decompose at lower temperatures. One example is magnesium carbonate, which breaks down into 11
  12. 12. magnesium oxide and carbon dioxide at 350 ° C. Inorganic solids are also known as minerals. b) Depending on its size. Dissolved. They pass through a filter. A fiberglass filter is generally used 0,45 μm. They can be classified as: Colloidal (0,001 - 1 μm). Not filtrables. They are suspended solids. c) According to its settling. For this determination the sample is settling in a 1L Imhoff cone for 1 hour, determining the volume of the settled sediments, expressed as mL/L. Not settling. Figure 3. Equipment for suspended solids determination. • Electrical conductivity. This value depends on the concentration of dissolved salts. It is measured by a conductivity tester. 12
  13. 13. Figure 4. Equipment for electrical conductivity determination. 5.2 Chemical Parameters. • pH. It refers to the concentration of hydrogen ions in the sample. It is measured with a pH meter. pH provides information on chemical reactions that can take place and on the biological activity of the sample. Figure 5. Equipment for pH determination. 13
  14. 14. • Alkalinity and acidity. The alkalinity of water is a measure of its capacity to neutralize acids. It is specifically defined as the amount of H+ ions that must be added to a certain volume of water for that it reaches a certain pH. Thus can be referred to Alkalinity to pH 8.2 (p-alkalinity) or Alkalinity to pH 4.3 (total alkalinity or m-alkalinity) Alkalinity is determined by titration with acid (H2SO4 generally or ClH). When the pH reaches 8.2, hydroxides and carbonates are determined, as species have become H2O and HCO3-. Total alkalinity is determined titrating until HCO3 becomes CO2 and H2O. Obviously, a pH 6.5 water will not present P-alkalinity, but total alkalinity. Alkalinity is usually expressed in mg/l CaCO3 and is a measure of the capacity of water to neutralize acids. The concept of acidity is the opposite to alkalinity, thus the amount of OH- ions that must be added to a certain volume of water to reach a certain value of pH. We also distinguish between acidity pH 4.3 and pH 8.2. • Hardness. Total hardness is given by the total content of calcium and magnesium ions. For its numerical expression it is referred to calcium carbonate or calcium oxide as parts per million (ppm) of calcium carbonate, ie milligrams of calcium carbonate per litre. There are two types of hardness: Temporary. It is due to calcium and magnesium bicarbonate. It is eliminated by boiling water when carbonate precipitates. Permanent. It is the remaining after boiling the sample. Total hardness is the sum of the two former. • Oxidation/reduction potential. It is the potential required to transfer electrons to a oxidizer from a reducer. It is measured with a potentiometer. This parameter is used to control water treatment processes in which reduction- 14
  15. 15. oxidation reactions are involves, such as chlorination, nitrification- denitrification, and so on. • Organic matter. There are three parameters to determine the organic matter: BOD5 (biochemical oxygen demand). It refers to the ppm of oxygen used by the bacterial population in five days to degrade at a temperature of 20 ° C the biodegradable organic matter present. This parameter is very important because it indicates the quantity of O2 necessary to stabilize organic matter and is very useful when designing a facility or determining the effectiveness of processes. The biochemical oxidation is a slow process. In 20 days the oxidation of organic matter comes at a 95-99%. At 5 days is 60 to 70%. There are mainly two ways to conduct the determination of the BOD. Dilution method To ensure that all other conditions are equal, a very small amount of micro- organism seed is added to each sample being tested. This seed is typically generated by diluting activated sludge with de-ionized water. The BOD test is carried out by diluting the sample with de-ionized water with added nutrients, saturated with oxygen, inoculating it with a fixed aliquot of seed, measuring the dissolved oxygen and sealing the sample (to prevent further oxygen dissolving in). The sample is kept at 20 °C in the dark to prevent photosynthesis (and thereby the addition of oxygen) for five days, and the dissolved oxygen is measured again. The difference between the final DO and initial DO is the BOD. The apparent BOD for the control is subtracted from the control result to provide the corrected value. The loss of dissolved oxygen in the sample, once corrections have been made for the degree of dilution, is called the BOD5. For carbonaceous BOD (cBOD), a nitrification inhibitor is added after the dilution water has been added to the sample. The inhibitor hinders the oxidation of nitrogen. This inhibition allows for measurement of carbonaceous oxygen demand (cBOD). BOD can be calculated by: 15
  16. 16. Undiluted: Initial DO - Final DO = BOD Diluted: ((Initial DO - Final DO)- BOD of Seed) x Dilution Factor Manometric method This method is limited to the measurement of the oxygen consumption due only to carbonaceous oxidation. Ammonia oxidation is inhibited. The sample is kept in a sealed container fitted with a pressure sensor. A substance absorbing carbon dioxide (typically KOH) is added in the container above the sample level. The sample is stored in conditions identical to the dilution method. Oxygen is consumed and, as ammonia oxidation is inhibited, carbon dioxide is released. The total amount of gas, thus the pressure, decreases because carbon dioxide is absorbed. From the drop of pressure, the electronics computes and displays the consumed quantity of oxygen. The main advantage of this method compared to the dilution method is its simplicity, thus no dilution of the sample, neither seeding, nor blank sample are required. Besides a continuous and direct reading of BOD value is displaied during the incubation time. Furthermore, as the BOD measurement can be monitored continuously, a graph of its evolution can be plotted. Interpolation of several graphs on a similar water may build an experience of its usual evolution, and allow an estimation of the five days BOD after as early as the first two days of incubation. 16
  17. 17. Figure 6. Equipment for BOD determination. COD (chemical oxygen demand). COD is defined as the O2 ppm consumed in the chemical oxidation of a sample of wastewater. Unlike the BOD, COD is a measure of total organic matter. The COD can be considered as an approximate measure of Theoretical Oxygen Demand. Depending on the components of the sample, this approach will be better or worse. For example, aromatic hydrocarbons and pyridine are not entirely oxidized, some very volatile organic substances can escape through evaporation and oxidation can occur of inorganic substances such as chloride (Cl-) and sulfides (S2-). The test takes place in heating reflux conditions with a known amount of potassium dichromate (K2Cr2O7). For the oxidation to be effective it must be done in an acidic medium (adding H2SO4) and in the presence of a catalyst (Ag2SO4). The reaction that takes place is the following: Cr2O72- +14H+ + 6e- ↔2Cr3+ + 7 H2O The measurement is carried out by assessing the remaining dichromate by means of a titration with ammonium sulfate or ferrous spectrophotometric. To cancel the interference of chloride, mercuric sulphate (HgSO4) is added, as the 17
  18. 18. mercury ion combines with the chloride ion to form mercuric chloride (HgCl2), which is essentially non-ionized. This test takes just over two hours, although techniques have been developed for roughly instrumental measuring the COD within minutes. Figure 7. Equipment for COD determination. • TOC (total organic carbon). It is commonly used to determine small concentrations of organic matter. This tests are based on organic matter carbon oxidation to CO2, measuring absorption by KOH or by infrared analysis. • Nitrogen. It is present in the form of organic nitrogen, ammonia, nitrites and nitrates, which can transform from one to another through the process of nitrification. Total Kjeldahl nitrogen (TKN) expresses the sum of organic nitrogen and ammonia nitrogen . The relative concentrations of different forms of nitrogen provide information on the degree of contamination of a sample. • Phosphorus. It is present as phosphates from detergents and fertilizers. It is not a direct risk to human or other lifeforms, but threatens water quality due to eutrophication. 5.3 Other parameters. In addition to the physical and chemical parameters, there are some others that should be determined depending on the nature of the aqueous sample: 18
  19. 19. • Harmful chemicals: cyanides, sulphides, phenols, fats and oils, detergents, pesticides, etc. • Pathogenic organisms. Since they are present in very small quantities, "indicator organisms” are needed, which are present in a greater quantity and whose presence in water is related to the former ones. An example of these indicator organisms are coliform bacteria. • Parameters that describe the toxicity of a sample. There are some tests to evaluate wastewater toxicity, which allows one to estimate the presence of toxic substances. As examples of widely used tests the following can be cited: AOX. It refers to the concentration in wastewater of substances absorbed in active carbon. METOX. It refers to the concentration of heavy metals. It is calculated as the addition of the values resulting from multiplying certain heavy metals’ concentrations by a coefficient indicating their potential risks. AOX and METOX express the concentration of certain toxic substances but not the toxicity itself, however, their determination is easy to be carried out as living organisms (that must be kept under certain conditions) are not required and, moreover, these parameters are appropriate to compare the toxicity of industrial wastewater (for example, METOX is often used to compare the toxicity of wastewater from galvanic industries). Inhibitor substances tests. They express toxicity as the interaction between effluent and environment and are based in preparing various dilutions of wastewater to find which concentration affects 50% of a population of microorganisms, either by inhibiting some of its properties (EC50) or causing its death (LC50). EC and LC are different from the ED and LD as the former refers to concentrations (substance mg/L of wastewater, for example), while the latter concern doses, ie, the weights of substances in an organism. 19
  20. 20. The organisms used to carry out these tests must be selected as representative of the ecosystem, sensitive to small concentrations of toxic substances and easy to handle. Daphnia (both Daphnia magna and Daphnia pulex) which is a micro crustacean, is mainly used in wastewater toxicity tests, evaluating the wastewater concentration that causes its inhibition or death, as well as luminescent bacterium Photobacterium phosphoreum, determining its luminescence loss when immersed in wastewater for 15 minutes. Lately most tests are conducted with the latter method because of its ease of handling. Toxicity is usually expressed in EQUITOX. An effluent presents N EQUITOX when a N dilution factor sample causes the inhibition of 50% of Daphnia population. Figure 8. Equipment for toxicity determination. The values of the most important parameters determining urban waste water are detailed in Table 5. 20
  21. 21. Table 5. Parameters determining urban waste water CONCENTRATION PARAMETER (ppm) HIGH MEDIUM LOW Total solids 1200 700 350 Suspended solids 350 200 100 BOD5 300 200 100 COD 1000 500 250 Total Nitrogen 85 40 20 Ammonia 50 25 12 Phosphorus 20 10 6 Fat 150 100 50 6. Legislation. 6.1. European Charter on Water Resources. COUNCIL OF EUROPE COMMITTEE OF MINISTERS Recommendation Rec (2001)14 Of the Committee of Ministers to member states on the European Charter on Water Resources (Adopted by the Committee of Ministers on 17 October 2001, at the 769th meeting of the Ministers’ Deputies) The Committee of Ministers, Recalling its adoption of the European Water Charter on 26 May 1967; Recalling its Decision No. CM/708/151298 to entrust the Committee for the Activities of the Council of Europe in the field of Biological and Landscape 21
  22. 22. Diversity (CO-DBP) to look into the advisability of reviewing and updating the European Water Charter; Considering that water is indispensable to all forms of life; Considering the importance of water in biological systems and the need to protect aquatic and associated ecosystems, and soil in particular; Considering that water is an ecological, economic and social asset that is a prerequisite for sustainable development; Considering that the preservation of water is the joint responsibility of states and all users; Considering that the increasing demand for water may lead to the deterioration and exhaustion of water resources and conflicts between users, as well as between states; Considering that water management constitutes an ideal area for action by the authorities in partnership with the various water users; Having regard to the greater knowledge available and growing public and government awareness since the adoption by the Council of Europe of the European Water Charter on 6 May 1968; Recalling the international instruments signed in this area, notably the Helsinki Convention on the Protection and Use of Trans boundary Watercourses and International Lakes of 17 March 1992, and the London Protocol on Water and Health of 17 June 1999, chapter 18 of Agenda 21 adopted in Rio de Janeiro in June 1992, the Sofia Convention on Co-operation for the Protection and Sustainable Use of the Danube River of 29 June 1994, the New York Convention on the Law of the Non-navigational Uses of International Watercourses of 21 May 1997 and the Bern Convention on the Protection of the Rhine of 12 April 1999; 22
  23. 23. Recognizing that the Directive 2000/60/EC of the Council of the European Union of 23 October 2000 incorporates many of the principles embedded in the European Water Charter, 1. adopts the European Charter on Water Resources, which replaces the European Water Charter proclaimed in Strasbourg on 6 May 1968; 2. recommends member states to take note of the charter and apply its principles as appropriate in the framework of their national policies. European Charter on Water Resources 1. Fresh water resources must be used in keeping with the objectives of sustainable development, with due regard for the needs of present and future generations. Fresh water constitutes only 2.7% of the Earth’s overall water mass, and to a large extent it is in a frozen state in the polar caps and the snow cover of high mountains. Humanity uses more than half of the planet’s water reserves: the quantity of water available per capita is now no more than 7 000 m3, as against 17 000 m3 as recently as 1950. At the same time, the world population is growing, and water needs are increasing, not only for domestic use (currently 6% of world consumption), but also for industry (20%) and above all for agriculture (70% to 80%). Water is not only of vital importance for all forms of life, and thus for the protection of the environment; its availability in sufficient quantity and quality is also a prerequisite for the development of human societies. It is thus at the heart of the concept of sustainable development, which brings together two fundamental aspects of society: the need to protect the environment, and the need to improve people’s living conditions. In 1987 this concept was defined as development which meets the needs of present generations without compromising the possibility for future generations of meeting theirs. 1 23
  24. 24. The International Court of Justice has summed up the situation as follows: “[The] need to reconcile economic development with protection of the environment is aptly expressed in the concept of sustainable development”. 2 The objectives of sustainable development 3 include promoting economic growth and improving social conditions, meeting essential needs, notably in terms of water, and conserving and maintaining natural resources. 2. Water must be equitably and reasonably used in the public interest. To determine what is equitable and reasonable, several factors must be considered: geographic, hydrographic, hydrological, climatic and ecological aspects; the economic and social needs of the populations concerned; the effects of the utilization of the resource on other users and the need to conserve water, harness water resources and avoid wastage, as well as the cost of measures taken to this end. It is also important to consider alternatives to existing or planned uses. All relevant factors are to be considered before reaching a conclusion, with special regard being given to meeting vital human needs. 4 3. Water policy and law must protect the aquatic ecosystems and wetlands. Water is an integral part of the ecosystem. It follows that water’s natural function must be conserved, restored and enhanced. Hence the need to ensure flow management that takes into account the natural flow of solid matter and promotes interaction between the river, ground water and alluvial zones in their capacity as natural flood zones. It is also necessary to conserve, restore and improve natural habitats for wild fauna and flora in water, particularly in the sediment and on riverbanks and lake shores, as well as in adjacent areas. The natural movements of fish must be preserved. 5 4. It is up to everyone to help conserve water resources and use them prudently, in conformity with this charter. As in the case of the environment generally, responsibility for conserving water resources cannot be regarded as being incumbent on the public authorities alone. The 1968 Charter noted that as a consumer and user of water, each human being 24
  25. 25. is responsible to other users and that to use water thoughtlessly is to misuse the natural heritage. 6 5. Everyone has the right to a sufficient quantity of water for his or her basic needs. International human rights instruments recognize the fundamental right of all human beings to be free from hunger and to an adequate standard of living for 7 themselves and their families. It is quite clear that these two requirements include the right to a minimum quantity of water of satisfactory quality from the point of view of health and hygiene. 8 Social measures should be put in place to prevent the supply of water to destitute persons from being cut off. 6. Public and private partners must introduce integrated management of surface water, ground water and related water that respects the environment as a whole, takes regional planning into account and is socially equitable and economically rational. Water management means planning the sustainable development of water resources and providing for the implementation of any plans adopted. 9 These operations must cover all expanses of fresh water, notably surface water and ground water, and take quantitative and qualitative aspects into account. Their objective must be to promote a dynamic, interactive and multi sector approach to water management and utilization based on community needs and priorities. 10 Rational water utilization schemes for the development of surface and underground water supply sources and other potential sources have to be supported by concurrent water conservation and wastage minimization measures. 11 7. Integrated management must be based on an inventory of water resources and aim to ensure their protection, conservation and, if necessary, rehabilitation. In particular, any new deterioration and exhaustion of these resources must be prevented, the recycling of waste water encouraged and, where appropriate, limitations placed on certain uses. 25
  26. 26. An inventory of water resources must include an assessment of their quantity and quality, taking into account the requisite present and future uses as well as the impact of foreseeable climate change. 12 Methods for the assessment of the toxicity of hazardous substances and the noxiousness of pollutants which are or might be discharged into water must be devised. Pollution from such substances should be gradually reduced. Environmentally sound technologies, production methods and consumption patterns must be developed and applied. 13 8. Water policy and law must be based on the principles of prevention, precaution and correction at source as well as the “polluter-pays” principle. To this end, they must use regulatory instruments such as quality objectives, discharge standards, the best available technologies and economic instruments compatible with meeting the population’s basic needs. These principles have been formulated in international instruments and should be applied to water resources in the following manner. The principle of prevention means that the emission of pollutants must be prevented, controlled and reduced at source through the application, in particular, of low- and non-waste technology. The risk of accidental pollution must be minimized and contingency planning developed. 14 The precautionary principle means that even in the absence of scientific certainty, adequate measures must be taken to prevent qualitative or quantitative deterioration of water resources when such deterioration might be serious or irreversible. Under the “polluter-pays” principle, the cost of pollution prevention, control and reduction measures must be borne by the polluter. Quality objectives determine the nature and quantity of pollutants acceptable in water. They may depend on the utilization contemplated for a given aquatic environment. Discharge standards define the maximum quantity of a given pollutant that may be discharged into the aquatic environment. The best available technology is taken to mean the latest stage of development of processes, facilities or methods of operation which indicate the practical 26
  27. 27. suitability of a particular measure for limiting discharges, emissions and waste. 15 Legal instruments in the strict sense of the term include the impact study procedure, which consists in requiring that, prior to implementation of a plan or project, its environmental impact be studied, and that rules imposing an obligation to obtain authorization for any activity that has a serious impact on the environment as well as monitoring of authorized discharges be laid down. 16 Economic instruments may include such measures as taxation of pollutants, tax relief on “clean” substances, quality seals certifying a product’s conformity with the environmental protection requirement, the obligation to take out insurance against environmental damage, negotiable authorization of pollutant emissions and subsidies or loans. The latter must, however, be compatible with the “polluter-pays” principle. All these instruments require a legal framework specifying the standards and objectives to be complied with or attained. In order to implement environmental protection measures, it is necessary to identify and strengthen or develop, as required, the appropriate institutional, legal and financial mechanisms. 17 9. Underground water resources must be the subject of special protection, and their use for human consumption must take priority. Ground water is usually connected with surface water and may be affected when watercourses are modified. Its quality is usually such that it should be set aside as far as possible for human consumption. Special measures must therefore be adopted to protect ground water from pollution, whether as a consequence of direct or indirect pollutants. 18 Ground water is particularly vulnerable to diffuse pollution from manuring and deposits of pollutants that seep into it through the soil. Preventive protection measures are needed, especially since the elimination of pollutants that have seeped into the ground water may take years or even decades. 10. Water resources must be regularly monitored and their general state periodically assessed. 27
  28. 28. Programs must be devised and implemented to monitor the state of water. They must provide for regular analyses to identify the causes of and parties responsible for pollution. 19 . Such programs must also make it possible to check whether the quality objectives have been attained as regards, in particular, the health of the population concerned and the state of the ecosystems, and whether safety measures to prevent accidents prejudicial to the quality or quantity of water resources are functioning properly. 11. The terms of water concessions must be compatible with this charter. Concessions must be granted for a limited duration and must be subject to periodic review. It is only fair that, as a counterpart to their rights and entitlements to water, natural and legal persons and institutions, whether in the public sector or the private sector, should contribute to the protection of the water environment and the conservation of water resources. 20 To ensure better supervision of compliance with this obligation, it is essential for such rights to be accorded for a limited duration only. Such limitation makes it possible to modify the terms of the agreement granting the right to exploit the water resources so as to take new data into account. At the same time, it encourages beneficiaries to be more careful about honoring their obligations. 12. Large-scale consumption of water in agricultural or industrial processes must be carefully assessed and monitored with a view to ensuring better protection of the environment and avoiding unsustainable utilization. The rapid increase in water needs makes it necessary to monitor constantly and adjust, as appropriate, the allocation of water resources for different uses. Reference should be made in this connection to the principles of sustainable development and the equitable and reasonable use of water resources, cited above. The holistic management of freshwater as a finite and vulnerable resource, and the integration of sector water plans and programs into national economic and social policy are of paramount importance. 21 28
  29. 29. 13. At each state level, central, regional and local authorities must adopt and implement water management plans in a spirit of solidarity and co-operation. These plans should be based on the catchment basin. Integrated water resources management, including land-related aspects, should be carried out at the level of the catchment basin or sub-basin. 22 This territorial fragmentation of responsibilities should not, however, be an impediment to an integrated water management policy at the level required. 23 A balance must be struck between a spirit of solidarity and co-operation and the need to base action on the dimensions of ecosystems, which usually coincide with those of catchment basins. 14. Decisions on water must take into account the particular conditions at regional or local level and be implemented by the relevant authorities closest to the areas concerned in keeping with water management plans. Whereas the utilization of water resources must be planned within the framework defined in the previous paragraph, the implementation of directives issued and decisions taken must be a matter for the local or regional authorities, which are closer to the users. This means that more account can be taken not only of the physical and ecological peculiarities of the various areas, but also of the human aspects and economic and social conditions that characterize them. 15. States must co-operate, preferably within permanent institutions, to agree on an equitable and reasonable method of managing international watercourses and other shared water resources in conformity with international law and the principles of this Charter. States that share a catchment basin must conclude bilateral or multilateral agreements specifying the geographic limits of their co-operation on the management of shared water resources. They must take into consideration requests concerning water transfers between catchment basins, and they must work to establish permanent institutions to ensure better co-operation on the management of shared water resources. These institutions can: - collect, compile and evaluate data in order to identify pollution sources; 29
  30. 30. - elaborate joint water monitoring programs; - draw up inventories and exchange information on pollution sources; - set emissions limits for waste water; - devise joint water quality objectives and criteria; - serve as a consultation forum for the smooth functioning and maintenance of facilities, installations and other structures associated with shared water resources; - develop action programs to reduce pollution loads; - establish warning and alarm procedures. 24 16. The public must have access to information on the state of water resources. The information collected on quantitative and qualitative aspects of water resources, notably on suitability for drinking, must be accessible to the public and published without delay in a form that is readily understandable. Provision must be made for special warning measures to protect public health. 17. The public must be informed in a timely and appropriate manner of water management plans and projects for the utilization of water resources. It has the right to take an active part in planning and decision-making procedures concerning water. Access to information and participation by natural and legal persons and their 25 associations, organizations or groups in the decision-making process concerning water resources are essential, in particular in order to enhance the quality and the implementation of the decisions, to foster public awareness of issues, to give the public the opportunity to express its concerns and to enable public authorities to take due account of such concerns. 26 The authorities must make available to the public as soon as possible information on water resources that is requested of them, including, if the request is made, copies of documents in which such information is actually 30
  31. 31. recorded, without the public needing to advance a particular interest. A request for information on water resources cannot be refused unless it concerns documents in the course of being prepared or if it is contrary to the rights of other persons protected by national legislation. Reasons for refusal must be interpreted restrictively and must be communicated to those concerned. 27 The public must also be able to participate in preparing plans and programs on water resources management at an appropriate stage. The relevant authority may identify the persons invited to participate. Sufficient time-frames must be fixed to allow for effective participation, and the public must be given the opportunity to comment, directly or through representative consultative bodies. The result of public participation shall be taken into account as far as possible. 28 18. The persons and bodies concerned must be able to appeal against any decision relating to water resources. Any natural or legal person wishing to contest any decision, act or omission and in particular any refusal to provide information or allow participation in connection with the management or utilization of water resources must be able to lodge an administrative or judicial appeal. 29 19. Without prejudice to the right to water to meet basic needs, the supply of water shall be subject to payment in order to cover financial costs associated with the production and utilization of water resources. Water has not only an ecological but also an economic value. In addition to water as such, infrastructure for its extraction, conveyance, distribution and purification generates costs which may vary from one place or community to another, but which cannot be ignored. Water, costing nothing, might be used wastefully, which is particularly dangerous in situations in which water resources are becoming relatively scarce. On the other hand, water is also a commodity with a social value, one that is necessary for meeting the basic needs of every human being. To finance the supply and purification of water, it is essential to implement the “polluter-pays” principle. To this end, appropriate charges must bez set 31
  32. 32. (proportional or progressive rates, rates for low-income categories or supply of a minimum quantity of water on preferential terms), depending on the use. Charges will depend on the expected evolution of water resources, the investment required and social considerations. The “user-pays” principle, pursuant to which the price of water available for given uses – and thus of adequate quality – must be borne by the user, must be taken into account, subject to basic needs being met. 6.2. Spanish Legislation. The Water Act, approved on 2 August of 1985 (Act 29/1.985), is the first to comprehensively address the problem of water pollution in Spain. The development of some titles of this law is carried out in the RD 1/2001, 20 July which approves the regulation of public water domain. These laws establish requirement to apply for official authorization for the discharge of water and waste products that are likely to pollute the waters. The authorisation granted by the administration lays down the conditions governing the discharge: • Limits of the discharge. Not exceeding the values given in Table 1 of Annex to the IV title. These values are reflected in Table 6. Tables 2 and 3, require a higher quality of discharge, and can be applied if necessary at any time by the Administration depending on the point of discharge. • Necessary wastewater treatment plants. • Facilities operation control. • Discharge fee according to section 105 of the Water Act. • Construction dates. • Emergency actions and measures. 32
  33. 33. Table 6. Discharge limits to reach. PARÁMETER (ppm) TABLE 1 TABLE 2 TABLE 3 pH 5,5-9,5 5,5-9,5 5,5-9,5 Suspended solids 300 150 80 Settling solids 2 1 0,5 Coarse solids Ausentes Ausentes Ausentes BOD5 300 60 40 COD 500 200 160 Color Inapreciable Inapreciable Inapreciable Al 2 1 1 As 1,0 0,5 0,5 Ba 20 20 20 B 10 5 2 Cd 0,5 0,2 0,1 Cr (III) 4 3 2 Cr (VI) 0,5 0,2 0,2 Fe 10 3 2 Mn 10 3 2 Ni 10 3 2 Hg 0,1 0,05 0,05 Pb 0,5 0,2 0,2 Se 0,5 0,03 0,03 Sn 10 10 10 Cu 10 0,5 0,2 Zn 20 10 3 33
  34. 34. Article 105 of the Water Act stipulates that the discharge authorized in accordance with the Articles 92 and following, are taxed with a fee to the protection and improvement of the receiving environment of each river basin. The fee is the result of multiplying the pollutant burden discharge C (expressed in units of pollution) by the value assigned to each unit p. Discharge fee C=Cp The unit of pollution is a standard measure pattern, that refers to the pollution load through the discharge rate of domestic water for 1,000 inhabitants and in a one-year period. The burden discharge C is obtained as follows:. C=K·V Where V is the volume discharged in one year period m3/y and K is a coefficient depending on the discharge characteristics 34
  35. 35. Table 7. K value ratio. DISCHARGE k ACCORDING TO TREATMENT CHARACTERISTICS TABLE 1 TABLE 2 TABLE 3 1) Domestic a) No industrial activity 1,0 0,20 0,10 b) Medium industrial activity 1,2 0,24 0,12 c) Important industrial activity 1,5 0,30 0,15 2) Industrial sector a) Tye 1 2,0 0,40 0,20 b) Type 2 3,0 0,60 0,30 c) Type 3 4,0 0,80 0,40 Recently, many regional governments have developed laws on discharge regulation, since their full attributions on environmental issues. Thus, the Valencian region has a law for discharge, treatment and reuse of wastewater since 1992 (Law 2 / 1992), introducing the concept of Sanitation Tax. The Sanitation Tax for industrial use is calculated annually as follows: Tax = (service fee + consumption fee) x corrective coefficient 35
  36. 36. The service fee depends on the size of the meter while the consumption fee’s value resulting of multiplying the volume of water consumed by the water price of €/m3, which is approved each year in the budget law. The corrective coefficient fee is equal to the multiplication of 3 indexes, which are: • volume factor, which is a function of the annual balance of water used in industry. • peak factor, which is a function of the peak flows and pollution loads. • corrective factor, depending on the value of certain wastewater characteristic parameters. 6.3. European Legislation. European legislation can be found at: http://eur-lex.europa.eu/RECH_menu.do?ihmlang=en The Council of Environment Ministers of the EEC adopted Directive 91/271/EC, on 21 May 1991, on urban waste water treatment. It establishes the following: • Definitions. p.e. (population equivalent)" means the organic biodegradable load having a five-day biochemical oxygen demand (BOD5) of 60 g of oxygen per day. • Regulations on sewage treatment, treatment in sensitive areas and less sensitive areas, etc.. • Deadline for compliance with these regulations. • Effect of wastewater from a member state over another. 36
  37. 37. • Regulations on industrial waste and sludge. Text of the Directive 91/271/EC COUNCIL DIRECTIVE of 21 May 1991 concerning urban waste water treatment (91/271/EEC) THE COUNCIL OF THE EUROPEAN COMMUNITIES, Having regard to the Treaty establishing the European Economic Community, and in particular 130s thereof, Having regard to the proposal from the Commission [1], Having regard to the opinion of the European Parliament [2], Having regard to the opinion of the Economic and Social Committee [3], Whereas the Council Resolution of 28 June 1988 on the protection of the North Sea and of other waters in the Community [4] invited the Commission to submit proposals for measures required at Community level for the treatment of urban waste water; Whereas pollution due to insufficient treatment of waste water in one Member State often influences other Member States' waters; whereas in accordance with Article 130r, action at Community level is necessary; Whereas to prevent the environment from being adversely affected by the disposal of insufficiently-treated urban waste water, there is a general need for secondary treatment of urban waste water; 37
  38. 38. Whereas it is necessary in sensitive areas to require more stringent treatment; whereas in some less sensitive areas a primary treatment could be considered appropriate; Whereas industrial waste water entering collecting systems as well as the discharge of waste water and disposal of sludge from urban waste water treatment plants should be subject to general rules or regulations and/or specific authorizations; Whereas discharges from certain industrial sectors of biodegradable industrial waste water not entering urban waste water treatment plants before discharge to receiving waters should be subject to appropriate requirements; Whereas the recycling of sludge arising from waste water treatment should be encouraged; whereas the disposal of sludge to surface waters should be phased out; Whereas it is necessary to monitor treatment plants, receiving waters and the disposal of sludge to ensure that the environment is protected from the adverse effects of the discharge of waste waters; Whereas it is important to ensure that information on the disposal of waste water and sludge is made available to the public in the form of periodic reports; Whereas Member States should establish and present to the Commission national programmes for the implementation of this Directive; Whereas a Committee should be established to assist the Commission on matters relating to the implementation of this Directive and to its adaptation to technical progress, HAS ADOPTED THIS DIRECTIVE: Article 1 This Directive concerns the collection, treatment and discharge of urban waste water and the treatment and discharge of waste water from certain industrial sectors. The objective of the Directive is to protect the environment from the adverse effects of the abovementioned waste water discharges. 38
  39. 39. Article 2 For the purpose of this Directive: 1. "urban waste water" means domestic waste water or the mixture of domestic waste water with industrial waste water and/or run-off rain water; 2. "domestic waste water" means waste water from residential settlements and services which originates predominantly from the human metabolism and from household activities; 3. "industrial waste water" means any waste water which is discharged from premises used for carrying on any trade or industry, other than domestic waste water and run-off rain water; 4. "agglomeration" means an area where the population and/or economic activities are sufficiently concentrated for urban waste water to be collected and conducted to an urban waste water treatment plant or to a final discharge point; 5. "collecting system" means a system of conduits which collects and conducts urban waste water; 6. "1 p.e. (population equivalent)" means the organic biodegradable load having a five-day biochemical oxygen demand (BOD5) of 60 g of oxygen per day; 7. "primary treatment" means treatment of urban waste water by a physical and/or chemical process involving settlement of suspended solids, or other processes in which the BOD5 of the incoming waste water is reduced by at least 20 % before discharge and the total suspended solids of the incoming waste water are reduced by at least 50 %; 8. "secondary treatment" means treatment of urban waste water by a process generally involving biological treatment with a secondary settlement or other process in which the requirements established in Table 1 of Annex I are respected; 9. "appropriate treatment" means treatment of urban waste water by any process and/or disposal system which after discharge allows the receiving waters to meet the relevant quality objectives and the relevant provisions of this and other Community Directives; 39
  40. 40. 10. "Sludge" means residual sludge, whether treated or untreated, from urban waste water treatment plants; 11. "eutrophication" means the enrichment of water by nutrients, especially compounds of nitrogen and/or phosphorus, causing an accelerated growth of algae and higher forms of plant life to produce an undesirable disturbance to the balance of organisms present in the water and to the quality of the water concerned; 12. "estuary" means the transitional area at the mouth of a river between fresh- water and coastal waters. Member States shall establish the outer (seaward) limits of estuaries for the purposes of this Directive as part of the programme for implementation in accordance with the provisions of Article 17 (1) and (2); 13. "coastal waters" means the waters outside the low-water line or the outer limit of an estuary. Article 3 1. Member States shall ensure that all agglomerations are provided with collecting systems for urban waste water, - at the latest by 31 December 2000 for those with a population equivalent (p.e.) of more than 15000, and - at the latest by 31 December 2005 for those with a p.e. of between 2000 and 15000. For urban waste water discharging into receiving waters which are considered "sensitive areas" as defined under Article 5, Member States shall ensure that collection systems are provided at the latest by 31 December 1998 for agglomerations of more than 10000 p.e. Where the establishment of a collecting system is not justified either because it would produce no environmental benefit or because it would involve excessive cost, individual systems or other appropriate systems which achieve the same level of environmental protection shall be used. 40
  41. 41. 2. Collecting systems described in paragraph 1 shall satisfy the requirements of Annex I (A). These requirements may be amended in accordance with the procedure laid down in Article 18. Article 4 1. Member States shall ensure that urban waste water entering collecting systems shall before discharge be subject to secondary treatment or an equivalent treatment as follows: - at the latest by 31 December 2000 for all discharges from agglomerations of more than 15000 p.e., - at the latest by 31 December 2005 for all discharges from agglomerations of between 10000 and 15000 p.e., - at the latest by 31 December 2005 for discharges to fresh-water and estuaries from agglomerations of between 2000 and 10000 p.e. 2. Urban waste water discharges to waters situated in high mountain regions (over 1500 m above sea level) where it is difficult to apply an effective biological treatment due to low temperatures may be subjected to treatment less stringent than that prescribed in paragraph 1, provided that detailed studies indicate that such discharges do not adversely affect the environment. 3. Discharges from urban waste water treatment plants described in paragraphs 1 and 2 shall satisfy the relevant requirements of Annex I.B. These requirements may be amended in accordance with the procedure laid down in Article 18. 4. The load expressed in p.e. shall be calculated on the basis of the maximum average weekly load entering the treatment plant during the year, excluding unusual situations such as those due to heavy rain. Article 5 1. For the purposes of paragraph 2, Member States shall by 31 December 1993 identify sensitive areas according to the criteria laid down in Annex II. 41
  42. 42. 2. Member States shall ensure that urban waste water entering collecting systems shall before discharge into sensitive areas be subject to more stringent treatment than that described in Article 4, by 31 December 1998 at the latest for all discharges from agglomerations of more than 10000p.e. 3. Discharges from urban waste water treatment plants described in paragraph 2 shall satisfy the relevant requirements of Annex I B. These requirements may be amended in accordance with the procedure laid down in Article 18. 4. Alternatively, requirements for individual plants set out in paragraphs 2 and 3 above need not apply in sensitive areas where it can be shown that the minimum percentage of reduction of the overall load entering all urban waste water treatment plants in that area is at least 75 % for total phosphorus and at least 75 % for total nitrogen. 5. Discharges from urban waste water treatment plants which are situated in the relevant catchment areas of sensitive areas and which contribute to the pollution of these areas shall be subject to paragraphs 2, 3 and 4. In cases where the above catchment areas are situated wholly or partly in another Member State Article 9 shall apply. 6. Member States shall ensure that the identification of sensitive areas is reviewed at intervals of no more than four years. 7. Member States shall ensure that areas identified as sensitive following review under paragraph 6 shall within seven years meet the above requirements. 8. A Member State does not have to identify sensitive areas for the purpose of this Directive if it implements the treatment established under paragraphs 2, 3 and 4 over all its territory. Article 6 1. For the purposes of paragraph 2, Member States may by 31 December 1993 identify less sensitive areas according to the criteria laid down in Annex II. 42
  43. 43. 2. Urban waste water discharges from agglomerations of between 10000 and 150000 p.e. to coastal waters and those from agglomerations of between 2000 and 10000 p.e. to estuaries situated in areas described in paragraph 1 may be subjected to treatment less stringent than that prescribed in Article 4 providing that: - such discharges receive at least primary treatment as defined in Article 2 (7) in conformity with the control procedures laid down in Annex I D, - comprehensive studies indicate that such discharges will not adversely affect the environment. Member States shall provide the Commission with all relevant information concerning the abovementioned studies. 3. If the Commission considers that the conditions set out in paragraph 2 are not met, it shall submit to the Council an appropriate proposal. 4. Member States shall ensure that the identification of less sensitive areas is reviewed at intervals of not more than four years. 5. Member States shall ensure that areas no longer identified as less sensitive shall within seven years meet the requirements of Articles 4 and 5 as appropriate. Article 7 Member States shall ensure that, by 31 December 2005, urban waste water entering collecting systems shall before discharge be subject to appropriate treatment as defined in Article 2 (9) in the following cases: - for discharges to fresh-water and estuaries from agglomerations of less than 2000 p.e., - for discharges to coastal waters from agglomerations of less than 10000 p.e. Article 8 1. Member States may, in exceptional cases due to technical problems and for geographically defined population groups, submit a special request to the Commission for a longer period for complying with Article 4. 43
  44. 44. 2. This request, for which grounds msut be duly put forward, shall set out the technical difficulties experienced and must propose an action programme with an appropriate timetable to be undertaken to implement the objective of this Directive. This timetable shall be included in the programme for implementation referred to in Article 17. 3. Only technical reasons can be accepted and the longer period referred to in paragraph 1 may not extend beyond 31 December 2005. 4. The Commission shall examine this request and take appropriate measures in accordance with the procedure laid down in Article 18. 5. In exceptional circumstances, when it can be demonstrated that more advanced treatment will not produce any environmental benefits, discharges into less sensitive areas of waste waters from agglomerations of more than 150000 p.e. may be subject to the treatment provided for in Article 6 for waste water from agglomerations of between 10000 and 150000 p.e. In such circumstances, Member States shall submit beforehand the relevant documentation to the Commission. The Commission will examine the case and take appropriate measures in accordance with the procedure laid down in Article 18. Article 9 Where waters within the area of jurisdiction of a Member State are adversely affected by discharges of urban waste water from another Member State, the Member State whose waters are affected may notify the other Member State and the Commission of the relevant facts. The Member States concerned shall organize, where appropriate with the Commission, the concertation necessary to identify the discharges in question and the measures to be taken at source to protect the waters that are affected in order to ensure conformity with the provisions of this Directive. Article 10 44
  45. 45. Member States shall ensure that the urban waste water treatment plants built to comply with the requirements of Articles 4, 5, 6 and 7 are designed, constructed, operated and maintained to ensure sufficient performance under all normal local climatic conditions. When designing the plants, seasonal variations of the load shall be taken into account. Article 11 1. Member States shall ensure that, before 31 December 1993, the discharge of industrial waste water into collecting systems and urban waste water treatment plants is subject to prior regulations and/or specific authorizations by the competent authority or appropriate body. 2. Regulations and/or specific authorization shall satisfy the requirements of Annex I C. These requirements may be amended in accordance with the procedure laid down in Article 18. 3. Regulations and specific authorization shall be reviewed and if necessary adapted at regular intervals. Article 12 1. Treated waste water shall be reused whenever appropriate. Disposal routes shall minimize the adverse effects on the environment. 2. Competent authorities or appropriate bodies shall ensure that the disposal of waste water from urban waste water treatment plants is subject to prior regulations and/or specific authorization. 3. Prior regulations and/or specific authorization of discharges from urban waste water treatment plants made pursuant to paragraph 2 within agglomerations of 2000 to 10000 p.e. in the case of discharges to fresh waters and estuaries, and of 10000p.e. or more in respect of all discharges, shall contain conditions to satisfy the relevant requirements of Annex I B. These requirements may be amended in accordance with the procedure laid down in Article 18. 45
  46. 46. 4. Regulations and/or authorization shall be reviewed and if necessary adapted at regular intervals. Article 13 1. Member States shall ensure that by 31 December 2000 biodegradable industrial waste water from plants belonging to the industrial sectors listed in Annex III which does not enter urban waste water treatment plants before discharge to receiving waters shall before discharge respect conditions established in prior regulations and/or specific authorization by the competent authority or appropriate body, in respect of all discharges from plants representing 4000 p.e. or more. 2. By 31 December 1993 the competent authority or appropriate body in each Member State shall set requirements appropriate to the nature of the industry concerned for the discharge of such waste water. 3. The Commission shall carry out a comparison of the Member States' requirements by 31 December 1994. It shall publish the results in a report and if necessary make an appropriate proposal. Article 14 1. Sludge arising from waste water treatment shall be re-used whenever appropriate. Disposal routes shall minimize the adverse effects on the environment. 2. Competent authorities or appropriate bodies shall ensure that before 31 December 1998 the disposal of sludge from urban waste water treatment plants is subject to general rules or registration or authorization. 3. Member States shall ensure that by 31 December 1998 the disposal of sludge to surface waters by dumping from ships, by discharge from pipelines or by other means is phased out. 4. Until the elimination of the forms of disposal mentioned in paragraph 3, Member States shall ensure that the total amount of toxic, persistent or bioaccumulable materials in sludge disposed of to surface waters is licensed for disposal and progressively reduced. 46
  47. 47. Article 15 1. Competent authorities or appropriate bodies shall monitor: - discharges from urban waste water treatment plants to verify compliance with the requirements of Annex I.B in accordance with the control procedures laid down in Annex I.D, - amounts and composition of sludge disposed of to surface waters. 2. Competent authorities or appropriate bodies shall monitor waters subject to discharges from urban waste water treatment plants and direct discharges as described in Article 13 in cases where it can be expected that the receiving environment will be significantly affected. 3. In the case of a discharge subject to the provisions of Article 6 and in the case of disposal of sludge to surface waters, Member States shall monitor and carry out any other relevant studies to verify that the discharge or disposal does not adversely affect the environment. 4. Information collected by competent authorities or appropriate bodies in complying with paragraphs 1, 2 and 3 shall be retained in the Member State and made available to the Commission within six months of receipt of a request. 5. Guidelines on the monitoring referred to in paragraphs 1, 2 and 3 may be formulated in accordance with the procedure laid down in Article 18. Article 16 Without prejudice to the implementation of the provisions of Council Directive 90/313/EEC of 7 June 1990 on the freedom of access to information on the environment [5], Member States shall ensure that every two years the relevant authorities or bodies publish situation reports on the disposal of urban waste water and sludge in their areas. These reports shall be transmitted to the Commission by the Member States as soon as they are published. Article 17 47
  48. 48. 1. Member States shall by 31 December 1993 establish a programme for the implementation of this Directive. 2. Member States shall by 30 June 1994 provide the Commission with information on the programme. 3. Member States shall, if necessary, provide the Commission by 30 June every two years with an update of the information described in paragraph 2. 4. The methods and formats to be adopted for reporting on the national programmes shall be determined in accordance with the procedure laid down in Article 18. Any amendments to these methods and formats shall be adopted in accordance with the same procedure. 5. The Commission shall every two years review and assess the information received pursuant to paragraphs 2 and 3 above and publish a report thereon. Article 18 1. The Commission shall be assisted by a Committee composed of the representatives of the Member States and chaired by the representative of the Commission. 2. The representative of the Commission shall submit to the committee a draft of the measures to be taken. The committee shall deliver its opinion on the draft within a time limit which the chairman may lay down according to the urgency of the matter. The opinion shall be delivered by the majority laid down in Article 148 (2) of the Treaty in the case of decisions which the Council is required to adopt on a proposal from the Commission. The votes of the representatives of the Member States within the committee shall be weighted in the manner set out in that Article. The chairman shall not vote. 3. (a) The Commission shall adopt the measures envisaged if they are in accordance with the opinion of the committee. (b) If the measures envisaged are not in accordance with the opinion of the committee, or if no opinion is delivered, the Commission shall, without delay, submit to 48
  49. 49. the Council a proposal relating to the measures to be taken. The Council shall act by a qualified majority. If, on the expiry of a period of three months from the date of referral to the Council, the Council has not acted, the proposed measures shall be adopted by the Commission, save where the Council has decided against the said measures by a simple majority. Article 19 1. Member States shall bring into force the laws, regulations and administrative provisions necessary to comply with this Directive no later than 30 June 1993. They shall forthwith inform the Commission thereof. 2. When Member States adopt the measures referred to in paragraph 1, they shall contain a reference to this Directive or shall be accompanied by such a reference on the occasion of their official publication. The methods of making such a reference shall be laid down by the Member States. 3. Member States shall communicate to the Commission the texts of the main provisions of national law which they adopt in the field governed by this Directive. Article 20 This Directive is addressed to the Member States. Done at Brussels, 21 May 1991. For the Council. The President. R. STEICHEN Annex I REQUIREMENTS FOR URBAN WASTE WATER A. Collecting systems (1) 49
  50. 50. Collecting systems shall take into account waste water treatment requirements. The design, construction and maintenance of collecting systems shall be undertaken in accordance with the best technical knowledge not entailing excessive costs, notably regarding: • volume and characteristics of urban waste water, • prevention of leaks, • limitation of pollution of receiving waters due to storm water overflows. B. Discharge from urban waste water treatment plants to receiving waters (1) 1. Waste water treatment plants shall be designed or modified so that representative samples of the incoming waste water and of treated effluent can be obtained before discharge to receiving waters. 2. Discharges from urban waste water treatment plants subject to treatment in accordance with Articles 4 and 5 shall meet the requirements shown in Table 1. 3. Discharges from urban waste water treatment plants to those sensitive areas which are subject to eutrophication as identified in Annex II.A (a) shall in addition meet the requirements shown in Table 2 of this Annex. 4. More stringent requirements than those shown in Table 1 and/or Table 2 shall be applied where required to ensure that the receiving waters satisfy any other relevant Directives. 5. The points of discharge of urban waste water shall be chosen, as far as possible, so as to minimize the effects on receiving waters. C. Industrial waste water Industrial waste water entering collecting systems and urban waste water treatment plants shall be subject to such pre-treatment as is required in order to: 50
  51. 51. • protect the health of staff working in collecting systems and treatment plants, • ensure that collecting systems, waste water treatment plants and associated equipment are not damaged, • ensure that the operation of the waste water treatment plant and the treatment of sludge are not impeded, • ensure that discharges from the treatment plants do not adversely affect the environment, or prevent receiving water from complying with other Community Directives, • ensure that sludge can be disposed of safety in an environmentally acceptable manner. D. Reference methods for monitoring and evaluation of results 1. Member States shall ensure that a monitoring method is applied which corresponds at least with the level of requirements described below. Alternative methods to those mentioned in paragraphs 2, 3 and 4 may be used provided that it can be demonstrated that equivalent results are obtained. Member States shall provide the Commission with all relevant information concerning the applied method. If the Commission considers that the conditions set out in paragraphs 2, 3 and 4 are not met, it will submit an appropriate proposal to the Council. 2. Flow-proportional or time-based 24-hour samples shall be collected at the same well-defined point in the outlet and if necessary in the inlet of the treatment plant in order to monitor compliance with the requirements for discharged waste water laid down in this Directive. Good international laboratory practices aiming at minimizing the degradation of samples between collection and analysis shall be applied. 3. The minimum annual number of samples shall be determined according to the size of the treatment plant and be collected at regular intervals during the year: - 2 000 to 9 999 p. e.: 12 samples during the first year. four samples in 51
  52. 52. subsequent years, if it can be shown that the water during the first year complies with the provisions of the Directive; if one sample of the four fails, 12 samples must be taken in the year that follows. - 10 000 to 49 999 p. e.: 12 samples. - 50 000 p. e. or over: 24 samples. 4. The treated waste water shall be assumed to conform to the relevant parameters if, for each relevant parameter considered individually, samples of the water show that it complies with the relevant parametric value in the following way: (a) for the parameters specified in Table 1 and Article 2 (7), a maximum number of samples which are allowed to fail the requirements, expressed in concentrations and/or percentage reductions in Table 1 and Article 2 (7), is specified in Table 3; (b) for the parameters of Table 1 expressed in concentrations, the failing samples taken under normal operating conditions must not deviate from the parametric values by more than 100 %. For the parametric values in concentration relating to total suspended solids deviations of up to 150 % may be accepted; (c) for those parameters specified in Table 2 the annual mean of the samples for each parameter shall conform to the relevant parametric values. 5. Extreme values for the water quality in question shall not be taken into consideration when they are the result of unusual situations such as those due to heavy rain. (1) Given that it is not possible in practice to construct collecting systems and treatment plants in a way such that all waste water can be treated during situations such as unusually heavy rainfall, Member States shall decide on measures to limit pollution from storm water overflows. Such measures could be based on dilution rates or capacity in relation to dry weather flow, or could specify a certain acceptable number of overflows per year. Table 1: Requirements for discharges from urban waste water treatment plants subject to Articles 4 and 5 of the Directive. The values for concentration or for the percentage of reduction shall apply. 52
  53. 53. Parameters Concentration Minimum Reference method of percentage of measurement reduction (1) Biochemical 25 mg/l O2 70-90 Homogenized, unfiltered, oxygen demand undecanted sample. (BOD5 at 20 40 under Determination of °C) without dissolved oxygen before nitrification (2) Article 4 (2) and after five-day incubation at 20 °C ± 1 °C, in complete darkness. Addition of a nitrification inhibitor Chemical 125 mg/l O2 75 Homogenized, unfiltered, oxygen demand undecanted sample (COD) Potassium dichromate Total 35 mg/l 90 (3) - Filtering of a suspended representative sample solids 35 under 90 under through a 0,45 ìm filter membrane. Drying at 105 Article 4 (2) Article 4 (2) °C and weighing (more than 10 000 (more than 10 - Centrifuging of a p.e.) 000 p.e.) representative sample (for at least five mins with 60 under 70 under mean acceleration of 2 800 to 3 200 g), drying at Article 4 (2) Article 4 (2) 105 °C and weighing (2 000-10 000 p.e.) (2 000-10 000 p.e.) (1) Reduction in relation to the load of the influent. (2) The parameter can be replaced by another parameter: total organic carbon (TOC) or total oxygen demand (TOD) if a relationship can be established between BOD5 and the substitute parameter. 53
  54. 54. (3) This requirement is optional. Analyses concerning discharges from lagooning shall be carried out on filtered samples; however, the concentration of total suspended solids in unfiltered water samples shall not exceed 150 mg/l. Table 2: Requirements for discharges from urban waste water treatment plants to sensitive areas which are subject to eutrophication as identified in Annex II.A (a). One or both parameters may be applied depending on the local situation. The values for concentration or for the percentage of reduction shall apply. Parameters Concentration Minimum Reference method of percentage measurement of reduction (1) Total phosphorus 2 mg/l P 80 Molecular (10 000 - 100 000 p. e.) absorption spectrophotometry 1 mg/l P (more than 100 000 p. e.) Total nitrogen (2) 15 mg/l N 70-80 Molecular absorption (10 000 - 100 000 p. e.) spectrophotometry 10 mg/l N (more than 100 000 p. e.) (3) (1) Reduction in relation to the load of the influent. (2) Total nitrogen means: the sum of total Kjeldahl-nitrogen (organic N + NH3), nitrate (NO3)-nitrogen and nitrite (NO2)-nitrogen. 54
  55. 55. (3) Alternatively, the daily average must not exceed 20 mg/l N. This requirement refers to a water temperature of 12° C or more during the operation of the biological reactor of the waste water treatment plant. As a substitute for the condition concerning the temperature, it is possible to apply a limited time of operation, which takes into account the regional climatic conditions. This alternative applies if it can be shown that paragraph 1 of Annex I.D is fulfilled. Table 3 : Series of samples taken in any year Maximum permitted number of samples which fail to conform 4-7 1 8-16 2 17-28 3 29-40 4 41-53 5 54-67 6 68-81 7 82-95 8 96-110 9 111-125 10 126-140 11 141-155 12 156-171 13 172-187 14 188-203 15 204-219 16 220-235 17 236-251 18 252-268 19 269-284 20 285-300 21 301-317 22 318-334 23 335-350 24 351-365 25 Annex II.CRITERIA FOR IDENTIFICATION OF SENSITIVE AND LESS SENSITIVE AREAS 55
  56. 56. A. Sensitive areas A water body must be identified as a sensitive area if it falls into one of the following groups: (a) natural freshwater lakes, other freshwater bodies, estuaries and coastal waters which are found to be eutrophic or which in the near future may become eutrophic if protective action is not taken. The following elements might be taken into account when considering which nutrient should be reduced by further treatment: (i) lakes and streams reaching lakes/reservoirs/closed bays which are found to have a poor water exchange, whereby accumulation may take place. In these areas, the removal of phosphorus should be included unless it can be demonstrated that the removal will have no effect on the level of eutrophication. Where discharges from large agglomerations are made, the removal of nitrogen may also be considered; (ii) estuaries, bays and other coastal waters which are found to have a poor water exchange, or which receive large quantities of nutrients. Discharges from small agglomerations are usually of minor importance in those areas, but for large agglomerations, the removal of phosphorus and/or nitrogen should be included unless it can be demonstrated that the removal will have no effect on the level of eutrophication; (b) surface freshwaters intended for the abstraction of drinking water which could contain more than the concentration of nitrate laid down under the relevant provisions of Council Directive 75/440/EEC of 16 June 1975 concerning the quality required of surface water intended for the abstraction of drinking water in the Member States (1) if action is not taken; (c) areas where further treatment than that prescribed in Article 4 of this Directive is necessary to fulfill Council Directives. (1) OJ No L 194, 25. 7. 1975, p. 26 as amended by Directive 79/869/EEC (OJ No L 271, 29. 10. 1979, p. 44). 56
  57. 57. B. Less sensitive areas A marine water body or area can be identified as a less sensitive area if the discharge of waste water does not adversely affect the environment as a result of morphology, hydrology or specific hydraulic conditions which exist in that area. When identifying less sensitive areas, Member States shall take into account the risk that the discharged load may be transferred to adjacent areas where it can cause detrimental environmental effects. Member States shall recognize the presence of sensitive areas outside their national jurisdiction. The following elements shall be taken into consideration when identifying less sensitive areas: open bays, estuaries and other coastal waters with a good water exchange and not subject to eutrophication or oxygen depletion or which are considered unlikely to become eutrophic or to develop oxygen depletion due to the discharge of urban waste water. Annex III INDUSTRIAL SECTORS 1. Milk-processing 2. Manufacture of fruit and vegetable products 3. Manufacture and bottling of soft drinks 4. Potato-processing 5. Meat industry 6. Breweries 7. Production of alcohol and alcoholic beverages 8. Manufacture of animal feed from plant products 9. Manufacture of gelatine and of glue from hides, skin and bones 10. Malt-houses 11. Fish-processing industry 57
  58. 58. 7. Wastewater treatment. Wastewater treatment plant (WWTP) can receive: • Domestic Wastewater from residential areas or commercial facilities. • Industrial wastewater. • Uncontrolled contributions to a public sewer. • Rainwater, resulting from surface runoff. A WWTP is designed to treat a certain flow. In case of a flow peak exceeding the WWTP capacity, excess flow can’t be treated as influent and so it should be bypassed. Once at the WWTP, wastewater must be pumped to overcome the head loss of the different stages. Centrifugal pumps are commonly used (Figure 9 a) as well as Archimedes screws. (Figure 9 b) Figure 9 a. Centrifugal pump. Quart Benager WWTP (Valencia). 58
  59. 59. Figure 9 b. Archimedes screws. Quart Benager WWTP (Valencia) Sewage treatments depends on: • Wastewater pollution degree (as characterization parameters seen above). • The quality of treated wastewater (effluent) to achieve. Wastewater treatments are the following: • Preliminary treatment. • Primary treatment. • Secondary treatments. • Tertiary treatment. 59
  60. 60. Figure 10. General view of Quart Benager WWPT (Valencia). 7.1. Preliminary treatment. Preliminary treatments remove solids, coarse materials, grit, sand, fats, etc, with a dual objective: • Reduction of wastewater pollution. • Protection of the following treatment stages. Processes found in a preliminary treatment. Their function is to protect the plant, removing large objects that could cause clogging and materials that can cause abrasion. The elimination of these substances is achieved by making water pass through gates or sieves. Coarse screens are classified as either bar racks or bar screens depending on the spacing between the bars. Both consist of vertical arrangement or equally spaced parallel bars designed to trap debris. 60
  61. 61. • Bar racks. They are made of steel, usually inclined about 60-80 º on the horizontal. This treatment effectiveness depends on the spacing between the bars, and it ranges approximately from 50 mm to 100 mm. Cleaning can be manual or automatic. Manual cleaning is done with a rake, while automatic cleaning can be done for example with a swivel arm. •. Bar screens. They are made of stainless steel. Spacing ranges between 6 mm to 50 mm. •. Fine screens and sieves . They are made of stainless steel and can be classified as rotary, vibrating, band, discs, stationary, etc. Opening ranges between 1 mm to 5 mm. Figure 11. Automatic screening equipment B. Grit removal systems. Wastewater grit materials ate generally non putrescible, have a settling velocity greater than that of organic materials, and consist of discrete particles. Such materials include sand, cinders, etc. A grit removal system consists of a wide canal, so that water velocity decreases allowing the deposition of sand. In the case of sewage it is difficult to prevent the settled 61

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