Die vorliegende Ausgabe beschäftigt sich mit dem Thema vergleichende Untersuchungen zur Wasseraufbereitung mit getauchten Membranen. Es werden drei Verfahren zur Aufbereitung von Oberflächenwasser zu Trinkwasser unter technischen, ökonomischen und ökologischen Gesichtspunkten verglichen. Das Verfahren der Ultrafiltration mit getauchten Membranen wurde dazu für drei Monate in einem kleintechnischen Pilotversuch an der Aare, Schweiz, getestet und hinsichtlich der Filtrationsleistung unter Variation typischer technischer Parameter bewertet. Für das konventionelle Verfahren mit Mehrschichtfiltration und die Ultrafiltration mit Rohrmodulen wurden die Ergebnisse vorangegangener Untersuchungen ausgewertet. Die anschließende Planung der Großanlagen bildet die Grundlage für den Vergleich. Keines der betrachteten Verfahren kann sowohl im technischen, ökonomischen als auch ökologischen Vergleich eindeutig seine Vorteilhaftigkeit herausstellen. Während die Ultrafiltration mit getauchten Membranen technisch die besten Noten erhält, ist die Wirtschaftlichkeit des konventionellen Verfahrens mit Mehrschichtfiltration mit dem höchsten Kapitalwert am günstigsten bewertet. Im Ergebnis der ökologischen Betrachtung wird das Verfahren der Ultrafiltration mit getauchten Membranen als umweltfreundlichste Variante identifiziert.

Since 1986 and especially during the early 90s, environmental protection has become a constitutional principle in Vietnam as regulated by Articles 17 and 29 of the 1992 Constitution. The first Law on Environmental Protection, passed by the National Assembly on December 27, 1993 created a foundation for environmental legislation becoming an important field in Vietnam’s legal system. In the following, Vietnam enacted its very first Law on Water Resources (No. 08/1998/QH10) in January 1999 aiming to provide a foundational framework for managing the water sector in Vietnam. In recent years, the legislative framework on water resources management has further developed. Important water-related regulations on the guidance and implementation of the Law on Water Resources have been issued and often amended to meet the requirements of the country’s development, and its international integration. To date, Vietnam’s legislation on the water sector consists of a complex system of legal documents issued by different state agencies. Though legislation of water sector management in Vietnam has greatly improved during the last decade, it has obviously not yet come to full fruition. Hence, the paper intends to provide an overview of achievements as well as problems and conflicting issues within Vietnam’s current water sector management legislation. / Kể từ năm 1986, đặc biệt là những năm đầu của thập kỷ 90, bảo vệ môi trường đã trở thành nguyên tắc hiến định (được quy định tại Điều 17 và 29 Hiến pháp 1992). Luật Bảo vệ môi trường đầu tiên được Quốc hội thông qua ngày 27 tháng 12 năm 1993 đã đặt nền móng cho việc hình thành hệ thống pháp luật về môi trường ở Việt Nam. Tiếp theo đó, ngày 20 tháng 05 năm 1998, Quốc hội nước Cộng hòa xã hội Việt Nam khóa X, kỳ họp thứ 3 đã thông qua văn bản luật đầu tiên về tài nguyên nước - Luật Tài nguyên nước số 08/1998/QH10 hình thành một nền tảng pháp lý cho hệ thống pháp luật bảo vệ nguồn tài nguyên nước ở Việt Nam. Trong những năm gần đây, hầu hết các văn bản dưới luật quan trọng và cần thiết cho việc hướng dẫn thi hành Luật Tài nguyên nước đã được ban hành và không ngừng được sửa đổi, bổ sung nhằm đáp ứng nhu cầu phát triển và hội nhập quốc tế của đất nước trong nhiều lĩnh vực khác nhau. Tuy nhiên, khung pháp lý hiện hành về tài nguyên nước ở Việt Nam bao gồm một hệ thống các văn bản quy phạm pháp luật khá phức tạp, nhiều tầng nấc, được ban hành bởi nhiều cơ quan có thẩm quyền khác nhau. Mặc dù hệ thống pháp luật về tài nguyên nước đã được liên tục sửa đổi, bổ sung và hoàn thiện trong suốt một thập kỷ qua, nhưng rõ ràng vẫn chưa thực sự đi vào cuộc sống. Bài viết dưới đây đề cập chủ yến đến một số các thành tựu cũng như những vấn đề mâu thuẫn hiện tại của pháp luật bảo vệ nguồn tài nguyên nước ở Việt Nam.

Craft villages played a significant role in the development of Vietnam’s rural economy for a long time. The range of products and production methods, including the processing of materials and chemicals, are now adapted to modern market requirements but environmental and labour protection issues are not adequately considered in the management of the craft villages. The reasons are various: poor education of responsible operators, deficient technical equipment or missing regulatory framework and implementation of existing regulations. The INHAND project (Integrated Water Management Concept for Craft Villages) started in 2011 and is studying the food processing village of Dai Lam located on the banks of the Cau River in the Bac Ninh province (about 40 km NE of the capital Hanoi). The household-scale business focus mainly on rice and cassava processing with 200 out of 1000 households producing alcohol from cassava and rice, 10 households producing tofu, and 30 households recycling aluminium. In addition, most households also raise pigs. The wastewater is released mostly untreated into the receiving stream. Within the framework of the INHAND project, four German und two Vietnamese partners will conduct a basic analysis inventory in the village with identification of suitable measure for an integrated, environmentally sound concept for the removal and reuse of all output streams. The second major task of the 3.5 years research project is the conceptualisation, development and implementation of pilot-scale treatment facilities in the village and the scientific monitoring of their planning and operation. / Đã từ lâu, làng nghề đóng vai trò quan trọng trong quá trình phát triển kinh tế nông nghiệp tại Việt Nam. Các sản phẩm và phương thức sản xuất, bao gồm cả giai đoạn xử lý vật liệu và hóa chất, đã từng bước được cải tiến cho phù hợp với yêu cầu của thị trường hiện đại. Tuy nhiên, những yếu tố về môi trường và an toàn lao động vẫn chưa được quan tâm đúng mức tại các làng nghề do nhiều nguyên nhân như: trình độ của nhà sản xuất, vận hành còn hạn hẹp, thiếu trang thiết bị kỹ thuật, các quy chuẩn còn thiếu hoặc chưa được thi hành triệt để. Dự án INHAND (đề án xử lý nước tổng thể cho làng nghề) được khởi động từ năm 2011 và hiện đang tiến hành nghiên cứu làng nghề chế biến thực phẩm Đại Lâm ,nằm bên bờ song Cầu, thuộc tỉnh Bắc Ninh, cách Hà Nội 40 km. Mô hình kinh tế hộ gia đình tại làng chủ yếu tập trung vào chế biến gạo và sắn: 200 trong số 1000 hộ gia đình nấu rượu gạo và sắn, 10 hộ sản xuất đậu phụ, 30 hộ tái chế nhôm. Ngoài ra, gần như tất cả các hộ đều có nuôi lợn. Nước thải của làng được dẫn trực tiếp ra các khối nước mở, gần như không qua xử lý. Trong khuôn khổ dự án INHAND, bốn đối tác Đức và hai đối tác Việt Nam sẽ tiến hành phân tích hiện trạng môi trường của làng để tìm ra những biện pháp thích hợp nhằm xử lý và tái sử dụng các dòng thải. Nhiệm vụ thứ hai trong thời gian 3,5 năm của dự án là lập ra đề án, phát triển và triển khai các trạm xử lý ở quy mô thử nghiệm, đồng thời quan trắc khoa học các quá trình thiết kế và vận hành.

Die vorliegende Ausgabe beschäftigt sich mit der systematischen Untersuchung potenzieller Einflussfaktoren auf die Lebenszykluskosten (LCC) von Abwasserpumpwerken. Betrachtungsobjekt ist eine Doppel-Tauchmotorpumpstation für den Einsatz in einer Trennkanalisation als Überpumpwerk für kommunales Schmutzwasser. Der zeitliche Betrachtungshorizont erstreckt sich über den gesamten Produktlebenszyklus. Primäres Ziel der Untersuchung ist die Identifizierung und Quantifizierung des Einflusses einzelner Systemparameter auf die Lebenszykluskosten. Aufgrund der Komplexität des betrachteten Systems kommt eine iterative Vorgehensweise zur Anwendung. Im ersten Iterationsschritt erfolgt eine separate Betrachtung des Systems aus technologischer, ökonomischer und ökologischer Sicht. Dabei werden aktuelle wissenschaftlich-theoretische Ansätze und Methoden auf ihre Anwendbarkeit auf die spezielle Problematik des Betrachtungsobjekts überprüft. Gemeinsam mit den Ergebnissen einer sich anschließenden System- und Umfeldanalyse stellen diese die Grundlage der separat entwickelten technischen, ökonomischen und ökologischen Einzelmodelle dar. In einer kritischen Würdigung werden diese drei Einzelmodelle auf Fehler, Schwächen und Stärken untersucht, um im zweiten Iterationsschritt in verbesserter Form zu einem integrierten technisch-ökonomisch-ökologischen Modell zusammengeführt zu werden. Mit Hilfe dieses Modells werden dann die zur Erreichung des Untersuchungsziels notwendigen, quantitativen Analysen (Sensitivitätsanalyse, Szenarioanalyse, Break-Even-Analyse, Payout-Analyse) des Betrachtungsobjekts durchgeführt. Die Analyseergebnisse werden ausgewertet und konkrete Handlungsempfehlungen abgeleitet, Forschungsbedarf wird aufgezeigt. Eine abschließende kritische Würdigung des Gesamtmodells soll zur weiteren Ver-besserungen der Modellierung in zukünftigen Untersuchungen anregen. Neben den quantitativen Analyseergebnissen ist das Gesamtmodell das wichtigste Ergebnis der Untersuchung, welches mit seiner softwaretechnischen Implementierung (Visual Basic 6.3 ? /MS Excel 2002?) ein Werkzeug liefert, das Entscheidungsträger sowohl auf strategischer als auch auf operativer Ebene unterstützen kann.

The handbook presented in this paper summarises the results of the research initiative “International Water Research Alliance Saxony” (IWAS). The subproject “IWAS Vietnam” (Phase I, October 2008 – December 2010) focuses on the model region “South-East Asia” with emphasis on Vietnam. The project started as a joint research initiative between German and Vietnamese organisations and included contributions from academic, private and public sector in both countries. The handbook was compiled by the Technische Universität Dresden (project coordination), the Institute for Technical and Scientific Hydrology and Dresden Drainage and Sewerage Company, with substantial contributions from Vietnamese partners. / Sổ tay hướng dẫn trong bài viết này tóm lược các kết quả của sáng kiến nghiên cứu từ “Liên minh Nghiên cứu ngành nước quốc tế bang Saxony” (IWAS). Dự án nhánh “IWAS Việt Nam” (giai đoạn 1, 10/2008 - 12/2010) tập trung vào khu vực Đông Nam Á với trọng tâm là Việt Nam. Dự án khởi động như một sáng kiến liên kết nghiên cứu giữa các tổ chức của CHLB Đức và Việt Nam với sự đóng góp từ các đơn vị tư nhân, nhà nước và trường đại học của cả hai quốc gia. Quyển sổ tay này được biên soạn bởi Đại học Kỹ thuật Dresden (cơ quan điều phối dự án), Viện Công nghệ và Khoa học Thủy văn, và Công ty Thoát nước Dresden, cùng với sự đóng góp quan trọng của các đối tác Việt Nam.

For cost and reliability efficiency, optimal design and operation of pressurized water distribution networks is highly important. However, optimizing such networks is still a challenge since it requires an appropriate determination of: (1) dimension of pipe / pump / tank - decision variables (2) cost / network reliability - objective functions and (3) limits or restrictions within which the network must operate - a given set of constraints. The costs mentioned here consist in general of capital, construction, and operation costs. The reliability of a network mainly refers to the intrinsic capability of providing water with adequate volume and a certain pressure to consumers under normal and extreme conditions. These contradicting objective functions are functions of network configuration regarding component sizes and network layout. Because considerable uncertainties finally render the overall task to a highly complex problem, most recent approaches mainly focus only on finding a trade-off between minimizing cost and maximizing network reliability. To overcome these limitations, a novel model system that simultaneously considers network configuration, its operation and the relevant uncertainties is proposed in this study. For solving this multi-objective design problem, a simulation-based optimization approach has been developed and applied. The approach couples a hydraulic model (Epanet) with the covariance matrix adaptation evolution strategy (CMA-ES) and can be operated in two different modes. These modes are (1) simulation–based Single-objective optimization and (2) simulation-based multi-objective optimization. Single-objective optimization yields the single best solution with respect to cost or network reliability, whereas multi-objective optimization produces a set of non-dominated solutions called Pareto optimal solutions which are trade-offs between cost and reliability. In addition, to prevent a seriously under-designed network, demand uncertainties was also taken into account through a so called “robustness probability” of the network. This consideration may become useful for a more reliable water distribution network. In order to verify the performance of the proposed approach, it was systematically tested on a number of different benchmark water distribution networks ranging from simple to complex. These benchmark networks are either gravity-fed or pumped networks which need to be optimally designed to supply urban or irrigation water demand under specific constraints. The results show that the new approach is able: • to solve optimization problems of pressurized water distribution network design and operation regarding cost and network reliability; • to directly determine the pumping discharge and head, thus allowing to select pumps more adequately; • to simulate time series of tank water level; • to eliminate redundant pipes and pumps to generate an optimal network layout; • to respond well to complex networks other than only to simple networks; • to perform with multiple demand loading; • to produce reliable Pareto optimal solutions regarding multi-objective optimization. In conclusion, the new technique can be successfully applied for optimization problems in pressurized water distribution network design and operation. The new approach has been demonstrated to be a powerful tool for optimal network design not only for irrigation but also for an urban water supply.

Driven by many factors, the water supply services (streamflow and groundwater) of many rivers in the dryland area of China have declined significantly. This aggravates the inherent severe water shortages and results in increased severity in the water use conflicts that are threatening sustainable development in the region. Innovative strategies towards more water-efficient land management are vital for enhancing water quantity to ensure water supply security. A key step in the successful development and implementation of such measures is to understand the response of hydrological processes and related services to changes in land management and climate. To this end, it was decided to investigate these processes and responses in the upper reaches of the Jing River (Jinghe), an important meso-scale watershed in the middle reaches of the Yellow River on the Loess Plateau (NW China). It has been shown that vegetation restoration efforts (planting trees and grass) are effective in controlling soil erosion on the Loess Plateau. Shifts in land cover/use lead to modifications of soil physical properties. Yet, it remains unclear if the hydraulic properties have also been improved by vegetation restoration. A better understanding of how vegetation restoration alters soil structure and related soil hydraulic properties, such as water conductivity and soil water storage capacity, is necessary. Three adjacent sites, with comparable soil texture, soil type, and topography but contrasting land cover (Black locust forest, grassland, and cropland), were investigated in a small catchment in the upstream Jinghe watershed (near Jingchuan, Gansu province). Seasonal variations of soil hydraulic properties in topsoil and subsoil were examined. Results revealed that the type of land use had a significant impact on field-saturated, near-saturated hydraulic conductivity, and soil water characteristics. Specifically, conversion from cropland to grass or forests promotes infiltration capacity as a result of increased saturated hydraulic conductivity, air capacity, and macroporosity. Moreover, conversion from cropland to forest tends to promote the formation of mesopores that increase soil water storage capacity. Tillage in cropland temporarily created well-structured topsoil, but also compacted subsoil, as indicated by low subsoil saturated hydraulic conductivity, air capacity, and plant available water capacity. An impact of land cover conversion on unsaturated hydraulic conductivities was not identified, indicating that changes in land cover do not affect functional meso- and microporosity. Changes in soil hydraulic properties and associated hydrological processes and services due to soil conservation efforts need to be considered, should soil conservation measures be implemented in water-limited regions for sustaining adequate water supply. To differentiate between the impacts of land management and climate change on streamflow, the variation of annual streamflow, precipitation, potential evapotranspiration, and climatic water balance in a small catchment of the upstream Jinghe watershed (near Pingliang, Gansu province) was examined during the period of 1955 – 2004. During this time the relative contributions of changes in land management and climate to the reduction of streamflow were estimated. A statistically significant decreasing trend of -1.14 mm y-1 in annual streamflow was detected. Furthermore, an abrupt streamflow reduction due to afforestation and construction of terraces and check-dams was identified around 1980. Remarkably, 74% of the total reduction in mean annual streamflow can be attributed to the soil conservation measures. Among various conservation measures, streamflow could be considerably reduced by afforestation and terracing (including damland creation), due to their low contribution to water yield. In contrast, slope farmland and grassland can maintain a certain level of water supply services due to higher runoff coefficients. According to a meta-analysis of the published studies on the Loess Plateau, the impact of changes in land management on annual streamflow appears to diminish with increasing catchment size while the impact of climate change appears uniform across space. This means that there is a dependency between the catchment size and the response of hydrological processes to environmental change. At least at the local scale, it appears that well-considered land management may help to ensure the water supply services. Due to limited surface water availability, groundwater is an essential water source for supporting ecosystem and socio-economic development in the dryland region. However, the groundwater process is susceptible and vulnerable to changes in climate and landscape (i.e., land cover and form) that in turn can result in profound adverse consequences on water supply services in water-limited regions. In addition, an improved understanding of the response of groundwater related processes to natural and artificial disturbances is likely to ensure more secure and more sustainable governance and management of such regions, as well as better options for adapting to climate change. Yet, this topic has seldom been researched, especially in areas that have already experienced large-scale alteration in landscape and are located in dryland regions, such as the Loess Plateau. Therefore, an investigation of the baseflow variation along the landscape change was conducted. The average annual baseflow has significantly decreased at catchment scale during the period of 1962 – 2002 without any obvious significant change in climate. At decadal scale, the reduction accounts for approximately 9% in the 1970s, 48% in the 1980s, and 92% in the 1990s, while the baseflow index declines averaging 5%, 16% and 67%, respectively. All of the monthly baseflow levels dropped at varying rates except in January, among which July was the most severe in terms of both magnitude (-4.17) and slope (-0.09 mm y-1). In perspective of landscape change, landform change (terrace and check-dam) tends to reduce baseflow by reallocation of surface fluxes and retention for crop growth causing limited deep drainage in other areas. Land cover change (i.e., afforestation) reduced the baseflow to a larger extent by enhanced evapotranspiration and thus hampered deep drainage as suggested by the soil moisture measurement underneath. The study indicates that knowledge about baseflow formation on catchment scale needs further improvement. Integrated soil conservation and water management for optimizing landscape structure and function in order to balance soil (erosion) and water (supply) related hydrological ecosystem services is vital. The governing processes to the changes of water-supply-services-related hydrological process (e.g., streamflow) are assumed to be different across space. To this end, the factors controlling streamflow were investigated on both a small and large scale. Streamflow in small catchments was found to be mainly controlled by precipitation and land cover type. On a larger scale, evaporative demand was found to be another additional major driving force. Hydrological modeling is a frequently used tool for the assessment of impacts of land use and climate change on water balance and water fluxes. However, application of the Soil and Water Assessment Tool (SWAT) model in the upstream Jinghe watershed was unsuccessful due to difficulties in calibration. The inability of the SWAT model to take the influence of terraces on steep slopes into consideration and the method how to calculate lateral flow were the main reasons for unsatisfactory calibration, at least for the current version of SWAT used in this study. Alternatively, Budyko’s frameworks were applied to predict the annual and long-term streamflow. However, the effect of changes in land management (e.g., afforestation) on streamflow could not be assessed due to a lack of vegetation factors. Therefore, an empirical analysis tool was derived based on an existing relationship for estimation. This method was found to be the most effective in reproducing the annual and long-term streamflow. The incorporation of temporal changes in land cover and form in the approach enables the estimation of the possible impact of soil conservation measures (e.g., afforestation or terracing). The importance of adaptive land management strategies for mitigating water shortage and securing the water supply services on the Loess Plateau was highlighted. A cross-sectoral view of the multiple services offered by managed ecosystems at different spatial scales under changing environments needs to be integrated to improve adaptive land management policy. In a water limited environment, such as the Loess Plateau, multiple ecosystem services including hydrological services need to be balanced with minimum trade-offs. This can only be achieved when management is based on a holistic understanding of the interdependencies among various ecosystem services and how they might change under alternative land management.