Recent practices on wastewater reuse in Turkey.

Reuse of wastewater for irrigational purposes in agriculture has been a widely applied practice all around the world compared to such applications in industries. In most of the developing countries, high costs of wastewater treatment stimulate the direct reuse of raw or partly treated effluent in irrigation despite the socio-cultural objections in some countries regarding religious rituals towards consuming wastewater. In Turkey, reuse applications in agriculture have been in use by indirect application by means of withdrawing water from the downstream end of treatment plants. Such practices affected the deterioration of surface water resources due to the lack of water quality monitoring and control. However, more conscious and planned reuse activities in agriculture have recently started by the operation of urban wastewater treatment plants. Turkey does not face any severe water scarcity problems for the time being, but as the water resources show the signs of water quality deterioration it seems to be one of the priority issues in the near future. The industrial reuse activities are only at the research stage especially in industries consuming high amounts of water. In-plant control implementation is the preferred effort of minimizing water consumption in such industries. The current reuse activities are outlined in the article forming an example from a developing country.     

Reuse of wastewater effluent for irrigation in severely arid regions

Al‐Hassa oasis, with an estimated population of 750000, is one of the main agricultural areas in Saudi Arabia. The estimated present agricultural water consumption in the oasis is almost 419 × 10⁶ m³ per year and the water is mainly supplied from the aquifer systems in the oasis. The climate is severely arid and the groundwater resources are limited. A deficiency in irrigation water supplies would occur in the oasis, especially during the summer season, without the reuse of wastewater effluent. Alternative schemes were developed on the basis of climatic, irrigation method, crop, health and economic considerations for the potential reuse of wastewater effluent for irrigation purposes. The schemes suggested different alternatives for reuse of the untreated effluent or with various types of additional treatments needed to render the water free of health hazards and suitable for agricultural use. An expected average wastewqter effluent of about 32.2 × 10⁶ m³/year will be available for irrigation purposes. This will result in minimizing the mining of groundwater and in conserving the water resources in Al‐Hassa oasis.     

Analysis of treated wastewater reuse potential for irrigation in Sicily

In Mediterranean countries, water shortage is becoming a problem of high concern affecting the local economy, mostly based on agriculture. The problem is not only the scarcity of water in terms of average per capita, but the high cost to make water available at the right place, at the right time with the required quality. In these cases, an integrated approach for water resources management including wastewater is required. The management should also include treated wastewater (TWW) reclamation and reuse, especially for agricultural irrigation. In Italy, TWW reuse is regulated by a quite restrictive approach (Ministry Decree, M.D. 185/03), especially for some chemical compounds and microbiological parameters. The aim of the paper is the evaluation of TWW reuse potential in Sicily. A Geographic Information System (GIS) was built at regional level to quantify and locate the available TWW volumes. In particular, the characteristics of wastewater treatment plants (WWTPs) were integrated, through the GIS, with data on irrigation district areas. Moreover, in order to evaluate the Italian approach for reuse practice in agriculture, the water quality of different TWW effluents was analysed on the basis of both the Italian standards and the WHO guidelines.     

Helminth ova control in wastewater and sludge for advanced and conventional sanitation.

Worldwide, the most important reuse of wastewater, in volume, is agricultural irrigation. Therefore, there is a need to properly treat wastewater for such purpose, considering the removal of pathogens while leaving suitable amounts of nutrients and other compounds to increase productivity. Helminth ova are one of the main targeted pathogens in the new guidelines for water reuse in agriculture and aquaculture issued in 2006 by the World Health Organization. However, relatively little research has been done recently on how to remove and inactivate helminth ova from wastewater and sludge and recommendations given several decades ago are still used, but when put into practice, particularly in developing countries, produce unsatisfactory results. One problem is that these criteria were developed using inaccurate analytical techniques and the other is the large number and variety of helminth ova species found in wastewater and sludge from the developing world. In fact, the few technological options to remove and inactivate helminth ova come from research performed using wastewater and sludge with low helminth ova content, and refer almost only to Ascaris (one type of helminth). This paper summarises recent research work and results from practical experience concerning helminth ova control for advanced and conventional sanitation.     

Aspects of municipal wastewater reclamation and reuse for future water resource shortages in Taiwan.

The Water Resources Agency (WRA), Ministry of Economic Affairs (MOEA) has predicted that the annual water demand in Taiwan will reach approximately 20 billion m3 by 2021. However, the present water supply is only 18 billion m3 per year. This means that an additional 2 billion m3 have to be developed in the next 17 years. The reuse of treated wastewater effluent from municipal wastewater treatment plants could be one target for the development of new water resources. The responsible government departments already have plans to construct public sewerage systems in order to improve the quality of life of the populace and protect the environment. The treated wastewater effluent from such municipal wastewater treatment plants could be a very stable and readily available secondary type of water resource, different from the traditional types of water resources. The major areas where reclaimed municipal wastewater can be used to replace traditional fresh water resources include agricultural and landscape irrigation, street cleaning, toilet flushing, secondary industrial reuse and environmental uses. However, necessary wastewater reclamation and reuse systems have not yet been established. The requirements for their establishment include water reuse guidelines and criteria, the elimination of health risks ensuring safe use, the determination of the wastewater treatment level appropriate for the reuse category, as well as the development and application of management systems reuse. An integrated system for water reuse would be of great benefit to us all by providing more efficient ways to utilise the water resources.     

Helminth ova removal from wastewater for agriculture and aquaculture reuse.

In the new version of the World Health Organization (WHO), water reuse guidelines helminth ova are considered one of the main target pollutants to be removed from wastewater reuse for agriculture and aquaculture purposes. In spite of this, along with the fact that helminth ova have been considered the main health risk to wastewater reuse for agriculture for at least 20 years, relatively little research has been done to control helminth ova in the wastewater treatment field. This paper addresses (1) characteristics of helminth ova and differences with microorganisms; (2) the most frequent helminth ova genus found in wastewater; (3) helminth ova content in developed and developing countries wastewater; (4) reasons why conventional disinfection methods cannot be applied; (5) main removal mechanisms; and (6) processes that in practice have effectively removed or inactivated helminth ova.     

Viability of increasing the tariff of freshwater for irrigation as a tool to stimulate wastewater reuse in the MENA region.

Despite water scarcity and high agricultural water demand in the Middle East and North Africa region, substantial proportions of treated wastewater are discharged into the environment and seas without proper utilization. All countries of the region, low pricing of reclaimed wastewater is a common tool to make reuse attractive. However, low pricing of reclaimed wastewater is ineffectual due to farmers' access to freshwater for irrigation at low tariff. Therefore, increasing the prices of freshwater in such a way that does not jeopardize feasibility of agriculture would promote irrigation with reclaimed wastewater even at increased prices. On one hand, it increases the gap between the price of freshwater and that of reclaimed wastewater, making the later more attractive. On the other hand, it would be used as a financial resource for funding the investment costs of the infrastructure needed for conveyance and distribution of reclaimed wastewater. This paper studies the viability of increasing the prices of freshwater and reclaimed wastewater. The results show that irrigation with reclaimed wastewater even for restricted irrigation can be as profitable as, and sometimes better than, freshwater irrigation. Some of the permitted crops such as fruit trees can be more profitable than vegetables. Thus, it appears that the level of knowledge farmers and others on the benefits of reclaimed wastewater is still limited.     

Water reuse for urban landscape irrigation: aspersion and health related regulations.

The Mediterranean seaside resort of Le Grau du Roi includes 40 hectares of landscaped areas spray irrigated with river water supplied through a separate network. Wastewater collected from several municipalities is treated in an activated sludge wastewater treatment plant (WWTP) and polished in waste stabilization ponds (WSPs). Planned substitution of treated wastewater for river water is hindered by spray irrigation prohibition within a 100 m distance from houses and recreational areas. WWTP and WSP effluents were monitored for pathogens with a particular attention to Legionella in Spring and Summer 2006. Helminth eggs, salmonellae and enteroviruses were never detected neither in WWTP effluent nor in the ponds. Legionella spp content was slightly higher or of the order of magnitude of river water contents. Regarding Legionella pneumophila contents, WSP effluent did not significantly differ from the river water. E.coli and enterococci contents in WSP effluents complied with the "excellent quality" criteria of the European Directive for coastal bathing waters. Therefore, substituting WSP effluents to river water is unlikely to alter health risks related to spray irrigation and, in this case, the buffer zone required by the French water reuse guidelines appears being short of support.     

利用小型污水处理设施和中水解决城镇水资源问题

水资源短缺和水环境污染已经成为城市和小城镇可持续发展的制约因素，中水回用则是解决这两个问题的重要举措。在调查分析了石家庄市水资源、污水处理和中水回用情况的基础上，回顾了污水处理和中水回用的发展历程，分析了中水回用的不同方法，以石家庄为例进行中水回用的经济效益分析。分析表明大力推行小型污水处理设施并进行中水回用是城市和小城镇水资源可持续发展的重要举措。     

Effluent standards for developing countries: combining the technology- and water quality-based approach.

It is a challenge for developing countries to realize socio-economical development without impairing water resources in an unacceptable way. A possible means for controlling water pollution is through defining, applying and enforcing effluent standards for wastewater discharges. However, in many developing countries the definition of effluent standards is still poor. They are either too stringent because they are based on standards from developed countries, or too relaxed and therefore they do not guarantee the safe intended uses of water. In order to define an approach for setting effluent standards that suits the needs and means of developing counties, water quality management practices in the USA, the EU, the New Independent States (NIS) and the Philippines were analyzed and compared. Four criteria (protection of the environment, technical viability, economic feasibility and institutional capacity requirements) were used to assess the suitability of these practices for developing countries. It is concluded that a combined approach that is based on best available technology not entailing excessive costs and environmental quality standards is the best way to define effluent standards that restrict water pollution against affordable costs.     

Agricultural Water Use in Turkey

Abstract

Agriculture is the largest user of water in Turkey with 75 percent of the total consumption. Turkey has developed 50 percent of total irrigable land so far. Water is a limiting factor for agriculture throughout much of Turkey. The amount and distribution of precipitation is quite uneven. Turkey, like many countries today, faces challenges in efficiently developing and managing its agricultural water resources while trying to protect water quality and the environment. However, Turkey has some difficulties and problems on water use for agriculture. Current institutional framework and legal regulation, monitoring and evaluation activities are investigated, and agricultural water use and irrigation development are studied. Problems with the lack of data on environmental effects of irrigation and water pricing are underlined. Evaluation of the current situation ends in the conclusion that Turkey needs a comprehensive monitoring and evaluation system both at basin and scheme level, and rehabilitation of irrigation systems for efficient water use in agriculture.     

Sustainability of Natural and Mechanized Aerated Ponds for Domestic and Municipal Wastewater Treatment in Palestine

Abstract

More than half of the current wastewater treatment facilities constructed in Palestine are waste stabilization ponds (WSP) and have several problems in their operation. This article evaluates three selected case studies on the various pond systems including WSP, algae- and duckweed-based ponds (ABP and DBP, respectively) and one mechanically aerated lagoon (AL) system. The effects of various design and operating parameters on the pond system' performance, with special emphasis on nitrogen removal, are discussed. The effluent quality of WSP and AL complies only with BOD limits, but not with microbiological limits prescribed for agricultural purposes, as determined by national standards. ABP and DBP achieved nitrogen removal only under high surface area demand (5-7 m2capita-1). Suitable plans for modifying existing aerated lagoons or for upgrading natural lagoons are suggested in order to comply with microbiological standards for effluent use in restricted irrigation. Finally, the suggested sustainability criteria for the evaluated pond systems may help the decision makers, as well as their designers and donor countries, to better select and design low-cost treatment options for sustainable wastewater management in developing countries.     

Simple wastewater treatment (UASB reactor, shallow polishing ponds, coarse rock filter) allowing compliance with different reuse criteria.

UASB reactors followed by polishing ponds comprise simple and economic wastewater treatment systems, capable of reaching very high removal efficiencies of pathogenic organisms, leading to the potential use of the effluent for unrestricted irrigation. However, for other types of reuse (urban and industrial), ponds are limited in the sense of producing effluents with high suspended solids (algae) concentrations. The work investigates a system with coarse rock filters for polishing the pond effluent. The overall performance of the system is analyzed, together with the potential for different types of reuse. The excellent results obtained (mean effluent concentrations: BOD: 27 mg/L; SS: 26 mg/L; E. coli: 450 MPN/100 mL) indicate the possibility of unrestricted use of the effluent for agriculture and restricted urban and industrial uses, according to WHO and USEPA.     

Grey water characterization and treatment for reuse in an arid environment

Grey water from a university facilities building in Cairo, Egypt was analysed for basic wastewater parameters. Mean concentrations were calculated based on grab samples over a 16-month period. Values for chemical oxygen demand (COD) and nutrients exceeded values reported in a number of other studies of grey water, while coliform counts were also high. A submerged membrane bioreactor (SMBR) system using a hollow fibre ultrafiltration membrane was used to treat the grey water with the aim of producing effluent that meets reuse guidelines for agriculture. A test run for 50 days at constant transmembrane pressure resulted in very good removal for key parameters including COD, total suspended solids (TSS), colour, turbidity, ammonia nitrogen, anionic surfactants, and coliform bacteria. High standard deviations were observed for COD and coliform concentrations for both monthly grab samples and influent values from the 50-day SMBR experiment. SMBR effluent meets international and local guidelines for at least restricted irrigation, particularly as pertains to COD, TSS, and faecal coliforms which were reduced to mean treated values of 50 mg/L, 0 mg/L (i.e., not detected), and <50 cfu/100 mL, respectively.     

An inventory analysis of rural pollution loads in China.

Rural pollution has attracted increasing attention over the past decade for its important consequences on surface and groundwater quality. This is particularly so in China due to the wide and effective control of industrial and municipal wastewater discharges over the past decade. Based on the discussion of rural activities in China, this paper develops a new method of inventory analysis through the definition of elementary unit (EU). This inventory analysis approach is then applied to estimate the total rural pollution loads of COD, TN and TP, as well as their spatial distributions in China. Further analysis is also conducted to investigate the correlations between rural pollution loads and agricultural production outputs, as well as population. It is found that China's agriculture is developing largely at the cost of environment quality, and a high population, as well as the increasing demand for agricultural products, is one of the dominant driving forces. The constructed EKC, which describes the relationship between rural pollution loads and agricultural income, also reveals that current agricultural development in China is mostly far from de-locked from the environmental problem.     

Urban and agricultural competition for water,and water reuse

Competition for water can be resolved by construction of more facilities for storing water in wet years for use in dry years, by weather modification, watershed management, urban and agricultural water conservation, reuse of sewage effluent and other wastewater, desalination of saline water, water banking and transfer of water rights or other changes in water use. Reuse of wastewater requires treatment so that the water meets the quality requirements for the intended reuse. Groundwater recharge and recovery can play an important role in the treatment and storage of wastewater for reuse—agricultural, urban, and industrial, as well as potable. Often, water shortages are only shortages of cheap and abundant water, and competition problems can be resolved by good planning and management if the public is willing to pay the price and to accept changes in water use.     

A Framework for Wastewater Reuse in Jordan: Utilizing a Modified Wastewater Reuse Index

Pressing water scarcity in Jordan rapidly increases the demands of marginal water resources for the agricultural sector. Water management studies reveal that no single source could fully solve the nation??s water shortage and many integrated actions are needed to ensure water availability, suitability and sustainability. Yet, among these options treated wastewater has the largest potential to augment water supply in the near future, thereby narrowing the gap between available freshwater and total demand. Indeed, treated wastewater could be a valuable source for irrigation in the agricultural sector and an increasing percentage of irrigated areas, especially in the Jordan Valley, are currently using treated wastewater. With a fast growing population and expansion of the irrigated areas to meet food demand, the pressure on water resources in Jordan remains of imminent importance. Hence, an urgent call to analyze the current and potential role of treated wastewater seems justified. Under the umbrella of the project on the Sustainable Management of Available Water Resources with Innovative Technologies (SMART) funded by the German Federal Ministry for Education and Research in Germany, an investigation has been carried out in the Jordan Valley to estimate the current wastewater reuse quantities and the potential to increase its utility for agricultural production. In general, the reuse as percentage of total treatment is applied for national and international comparisons. Yet, this index is of limited use for policy decisions as it does not reflect potentialities of wastewater use. Therefore, this study introduces a wastewater reuse index (WRI) that reflects the actual proportion of wastewater reused from the total generated wastewater. We found that the WRI in Jordan steadily increased from 30% in 2004 to 38 in 2007. Efficient use of treated wastewater requires the application of new technologies in Jordan like dwellings connected to the sewer system, decentralization of treatment plants to rural and urban settlements and prevention of high evaporation rates from stabilization ponds.     

Possibilities for reuse of treated domestic wastewater in the Netherlands

The implementation of wastewater reuse is becoming an increasingly important means of supplementing water supply needs and/or reducing costs. The present paper provides examples of possible uses of treated domestic effluent for the three sectors, i.e. public water supply, industrial and agricultural uses with the aim to address the feasibility of these applications. It is concluded that, although The Netherlands as a whole is considered to be a low water stressed country, regional fresh water scarcity and costs can result in the need for applications of domestic wastewater reuse.     

Hydrosocial territories in the context of diverse and changing ruralities: the case of Cochabamba’s drinking water provision over time

ABSTRACT

The article describes the history of drinking water provision of the city of Cochabamba, Bolivia, as an instructive case for analyzing the dynamic reconfiguration of hydrosocial territories and rural–urban relations over time. Cochabamba’s growing drinking water demand obliged the city to expand its access to water sources, involving diverse rural areas and groups of rural inhabitants. Using the concept of hydrosocial territories, the history of Cochabamba’s water solutions is explored, showing the need to analyze rural actors in a differentiated way in order to understand their (changing) role in the configuration of the hydrosocial territories.