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Rationing of Water Use. Expert Assessment of Wastewater Treatment Systems
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6. RATIONING OF WATER USE. EXPERT ASSESSMENT OF WASTEWATER TREATMENT SYSTEMS
An important aspect of minimizing of the adverse impact on water bodies is the decrease in volume of water collection from the natural sources for different purposes.
Since water use and wastewater disposal are two interrelated functions (water disposal is equal to water use minus irretrievable water use and irretrievable losses), the decrease in water use will lead to decrease in water disposal, which in its turn, will lead to the reduction of the load on treatment facilities and thus to the increase in their efficiency and, as a result of it, the increase in water quality.
Under the current economic conditions the issue of decrease in water use and wastewater discharges must be solved based on non capital-intensive measures, such as rationing of water use.
The decrease in water use and disposal may be achieved through the combination of the following two measures: setting quotas on water use and disposal per unit of product at manufacturing enterprises and measuring and recording of the fresh water consumed and wastewater discharged.
This conception is based on the fact that without one of the above two factors it is impossible to make an objective judgment about the efficiency of water use by an enterprise and to provide a basis for quotas of water use. That is why, in the process of development of conceptual approaches to the improvement of water quality management, rationing and measuring must be viewed as two complementary components that determine the efficiency of use and protection of water resources.
Rationing of water use and disposal means setting of a planned limit for the use of water and disposal of wastewater. In terms of rationing, the factual use of water by a manufacturing enterprise consists of 2 parts – normal and excess - and can be described by the following equation:
= +
Hence, there are two possible methodological approaches to the setting of the quotas: either to estimate the ‘normal’ part or ‘excess’ part of water consumption. Since these are two independent methods, the first one is recommended for the establishment of the quotas, the second – for the establishment of an expert system of water rationing.
In the former Soviet Union, the quotas of water use and disposals were set according to the first method. This process was not regulated by water legislation. The quotas were laid down in the industrial methodological documents and were mostly of two types: individual (for manufacturing enterprises) and aggregative (for entire industries).
The individual quotas of water use and disposal determined the amount of water used (disposed) per production unit and with consideration of all water uses (technological, supporting and auxiliary, domestic and drinking uses) and the quality of water used (disposed). The individual quotas were set:
- to estimate the water needs of a manufacturing enterprises;
- to ration water supply and wastewater discharge for manufacturing enterprises;
- to design water-supply and sewage systems of manufacturing enterprises;
- to control water use and discharge at manufacturing enterprises.
Aggregative quotas of water use (disposal) determined the quantity of water used (disposed) per production unit according to the established aggregative list of products as weighted-mean values of individual quotas and production volumes. The aggregative norms were used to make forecasts and feasibility studies, to design water supply and sewage systems of manufacturing enterprises, and to work out schemes of integrated use and protection of water resources of river basins. The aggregative quotas were used by ministries and departments managing different branches of national economy.
In the Republic of Belarus, rationing of water use was initiated by the adoption of the Water Code of the Republic of Belarus (1998).
According to Article 15 of the Water Code, technological (branch) quotas of water consumption (water use and disposal) are established to assess and ensure the efficiency of water use and protection. These quotas are defined in terms of quantity and quality of water needed for production and the corresponding quantity of wastewater with maximum allowable concentrations of pollutants in it per unit of a major product and raw materials.
It is a rather broad formula, which needs to be further specified. In addition to the above articles of the Water Code and the law “On environmental protection” it is necessary to develop regulations governing the rationing of water use in the Republic of Belarus and to adopt the appropriate Resolution of the Council of Ministers of the Republic of Belarus.
It is advisable to introduce quotas of water use stage wise starting form the most water consuming productions. At the initial stage this measure will make it possible to control the efficiency of water use by water consuming enterprises and to achieve its tangible decrease as well as significant saving of electricity spend on pumping of the excess water.
For all enterprises of different industries, quotas of water use must be set on common methodological grounds. To this end, it is necessary to bring the existing methodology, developed in the former Soviet Union, in compliance with the Water Code and bylaws regulating water use in the Republic of Belarus with consideration of recommendations based on the new approach to the setting of the quotas.
Quotas must be adjusted with a special expert system developed regardless of diverse production technologies and based on statistical analysis of the retrospective data of enterprises on their water use and disposal, production of their main products or raw materials.
Another important aspect of minimizing the adverse impact on water bodies is the increase of the efficiency of treatment facilities.
As it was already mentioned above, the strategic goal of the sate and society is the sustainable development. Working towards this goal, it is necessary to develop and justify a holistic system of approaches to environmental safety, including operational safety of treatment facilities as one of the major sources diminishing the water quality in the Dnipro River. At present there are no legally imposed general environmental restrictions based on the principles and requirement of environmental safety and sustainable development in the environmental legislation of Belarus.
The practice of imposing restrictions on the use of water resources is in accord with the general principle of balancing the environmental and economic needs.
The schemes of treatment must be chosen depending on the allowable load on a water body, the available material, financial, and technical resources and the criteria of hygienic, fish and environmental damage resulting from the deviation of water quality from the norm. At the same time the environmental legislation must provide for a fundamentally different method of assessing the degree of wastewater treatment – standards must be established on the basis of the achieved level of treatment technology. This is very important since one of the current objectives of the Republic of Belarus is to develop and implement programs of technical re-equipment and reconstruction of manufacturing enterprises and their continuous modernization on the basis of new technologies.
To define the allowable load on a water body, it is necessary to analyze the quality of its water, to identify and classify all the pollution sources and to assess the impact of each of them on the quality of water. The results of identification and ranking of the pollution sources according to pollution types are used to prioritize water protection measures.
Thus, the two principles of a basin scheme of wastewater treatment are prioritization and comprehensive approach, which consists in both the coverage of all wastewater types and the system of water conservation and water protection measures for wastewater sources.
Increasing the efficiency of local treatment facilities at manufacturing enterprises is currently an issue in the Republic of Belarus, however there are no tools for measuring this efficiency. The only efficiency criterion is the ability of treatment facilities to ensure MAC in the wastewater discharged into municipal sewage systems, or, which is much more rarely, into water bodies used for the purposes of fishing or drinking water supply. This is a valid criterion even in those cases, when it is technologically unfeasible to achieve the required MAC.
Following are the measures to be taken to deal with this issue:
1. To take a complete inventory of all treatment facilities
This is possible to achieve by means of questionnaires and there is sufficient experience in doing this. However whole process of inventory taking of manufacturing enterprises must be set on legal grounds. To this end it is necessary to work out and get approved the registration certificate issued to an enterprise that must be annually renewed and submitted to a basin management agency.
2. To rank enterprises according to the types of pollution, to make long-term plans of reconstruction of treatment facilities within the Dnipro basin, to set the priorities (because of the limited funding)
Basin management agencies, which are the most interested party in the efficient use of the capital invested in construction and reconstruction of treatment facilities and in the improvement of water quality, will rank wastewater treatment facilities according to the types of pollution and will set the priorities in their funding.
We suggest using schemes of wastewater treatment in certain industries worked out within the program of “Use and Protection of Natural Environment” as a tool assisting in identification of the priority areas. As a result of completion of this project, wastewater sources were classified according to the types of waste with regard of the type of an enterprise, pollutant concentrations and costs. The schemes of wastewater treatment were developed depending on the conditions of discharge of treated waste. In the process of their development the experience in designing of the systems of treatment of municipal and industrial wastewater was considered. The proposed schemes maintain modern technological and environmental standards of such systems. It is also significant that the available literature provides the description of either methods of treatment or treatment facilities. The proposed schemes describe the entire process of treatment at an enterprise of selected industry.
3. To establish methodological grounds
Due to the lack of the appropriate standard setting documents it is necessary to develop and get approved a methodology or methodological guidelines for the application of the developed schemes in the analysis of local treatment facilities. If necessary, similar schemes must be produced for the other industries.
4. To provide environmental education and training to the experts and personnel operating treatment facilities
Much attention must be paid to the level of technical knowledge of the specialists conducting expert examination of the construction projects of wastewater treatment facilities as well as the level of technical skills of the personnel attending treatment facilities. The proposed schemes enable specialist to quickly assess the expediency and economic effect of the proposed solutions. That is why it is proposed to use these schemes in a publication of a training and reference manual.
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