Suchergebnisse

ABSTRACTPond structures as cost‐effective source‐control drainage techniques can be applied in order to reduce the downstream risk of flooding. In the UK, there are no widely accepted performance data on pond structures, yet there is a need for detailed design and operation guidelines, coupled with data on urban biodiversity enhancement, maintenance, reliability, economics and social acceptance. The purpose of this study was to investigate (a) cost‐effectiveness and self‐sustainability of stormwater pond systems, and (b) compatibility with the primary needs of water removal and storage to wildlife and amenity enhancement. A case study was used, based upon a combined attenuation wetland and dry pond construction for roof‐water runoff.

Textile industries are responsible for one of the major environmental pollution problems in the world, because they release undesirable dye effluents. Textile wastewater contains dyes mixed with various contaminants at a variety of ranges. Therefore, environmental legislation commonly obligates textile factories to treat these effluents before discharge into the receiving watercourses. The treatment efficiency of any pilot-scale study can be examined by feeding the system either with real textile effluents or with artificial wastewater having characteristics, which match typical textile factory discharges. This paper presents a critical review of the currently available literature regarding typical and real characteristics of the textile effluents, and also constituents including chemicals used for preparing simulated textile wastewater containing dye, as well as the treatments applied for treating the prepared effluents. This review collects the scattered information relating to artificial textile wastewater constituents and organises it to help researchers who are required to prepare synthetic wastewater. These ingredients are also evaluated based on the typical characteristics of textile wastewater, and special constituents to simulate these characteristics are recommended. The processes carried out during textile manufacturing and the chemicals corresponding to each process are also discussed.

ABSTRACTThe aim of this project was to assess the influence of a full silt trap on the quality of stormwater which was discharged into an urban watercourse. The average SS concentrations of the outflow were 2.0 and 34.1 mg/l during dry‐weather and wet‐weather conditions, respectively, and SS concentrations of up to 141.6 mg/l were recorded during storms. Treated stormwater SS concentrations were often high, compared with secondary sewage‐treatment standards of ≤30 mg/l. Pollutants accumulated in the silt trap.

AbstractThis paper describes an investigation into the treatment efficiency and capital cost of vertical‐flow constructed‐wetland filters containing different plant communities and granular media with different adsorption capacities. The media included gravel, sand, granular‐activated carbon, charcoal and filtralite (light expanded clay). Lead and copper sulphate were added to a polluted urban beck inflow water to simulate pretreated minewater or highway runoff. The interactions between growth media, microbial and plant composition and the reduction of lead, copper and BOD were investigated. For filters containing traditional media, a breakthrough of copper was recorded during the first nine weeks. After maturation of the biofilm, the wetlands performed well.

Die aus den Jahren 1968-1977 vorliegenden Meldungen der Pflanzenschutzämter weisen darauf hin, daß erste Beobachtungen von Rhynchosporium secalis auf Wintergerste in der Bundesrepublik Deutschland selten im März, häufiger aber im April und Mai gemacht werden. Relativ hohe Temperaturen im März scheinen vermehrtes Auftreten zu "verfrühen". Dagegen wurde kein Zusammenhang zwischen dem Termin solchen ersten stärkeren Auftretens und der Anzahl der Regentage bzw. der Regenmenge gefunden. ; Reports of the government plant protection bureaux in the Federal Republic of Germany on the occurrence of Rhynchosporium secalis on cereals have been analyzed. On winter barley the disease may first appear in March if monthly mean March temperatures are high. More usually, early records of occurrence are made in April, even May. No relation between the amount of rainfall and the number of rainy days and the first appearance of the disease has been found.

AbstractThis paper presents a case study which describes water‐availability problems and corresponding public‐health implications for a rural area in Nigeria. A water‐availability assessment was carried out in eight villages which are controlled by the Jalingo Local Government of Taraba State. Questionnaires were used to obtain data from sixty households (approximately 650 participants) concerning issues of water‐supply sources, water quantity, water quality and community participation in water‐resources projects. It was found that (i) community well water is the major source of water, (ii) 35% of the inhabitants depend on well water during the wet season, and (iii) 69% depend on it during the dry season. About 80% of the households have access to less than 30 litres of water per person per day and, because of low water availability, there is a prevalence of water‐related diseases.

In developing countries, there is often a lack of a comprehensive data set that supports the development of coherent policies on resource recovery from wastewater treatment. This paper aims to contribute to the elaboration of resource recovery projects by providing accurate and updated data from wastewater treatment plants such as those located in the region of the Macrometropolis of Sao Paulo. The authors discuss possibilities of improvement of resource recovery for this illustrative example. Comprehensive analyses were performed based on data from 143 municipal wastewater treatment plants to understand the situation regarding resource recovery implementation in this region. The results show that just 26% of the plants perform at least one resource recovery practice. The predominant resource recovery practice is internal water reuse, and recovery is concentrated more in large plants than in medium and small ones. The sludge is disposed in landfills except for three plants, which perform sludge recycling for compost. Some plant managers reported interest in recovering energy from biogas, in expanding water reuse and in recovering sludge for fertilizer production or for building materials. Several aspects that have been regarded as relevant to the implementation of resource recovery processes in previous literature are discussed, such as the size of the plant, related legislation as well as treatment technologies and configurations. Finally, the authors propose a generic framework with several steps that can help to achieve resource recovery implementation. Therefore, the results can provide support for planning of resource recovery projects for large cities in developing countries. [Abstract copyright: Copyright © 2020 Elsevier Inc. All rights reserved.]

Climate variability is heavily impacting human health all around the globe, in particular, on residents of developing countries. Impacts on surface water and groundwater resources and water-related illnesses are increasing, especially under changing climate scenarios such as diversity in rainfall patterns, increasing temperature, flash floods, severe droughts, heatwaves and heavy precipitation. Emerging water-related diseases such as dengue fever and chikungunya are reappearing and impacting on the life of the deprived; as such, the provision of safe water and health care is in great demand in developing countries to combat the spread of infectious diseases. Government, academia and private water bodies are conducting water quality surveys and providing health care facilities, but there is still a need to improve the present strategies concerning water treatment and management, as well as governance. In this review paper, climate change pattern and risks associated with water-related diseases in developing countries, with particular focus on Pakistan, and novel methods for controlling both waterborne and water-related diseases are discussed. This study is important for public health care, particularly in developing countries, for policy makers, and researchers working in the area of climate change, water quality and risk assessment.

AbstractThis paper is primarily aimed at encouraging further use of neural networks by the water‐ and wastewater treatment industry. The study demonstrates the principle of using a network method of simulating the performance of a biological activated‐carbon filter based on a biological water‐quality assessment and measurements of pH and dissolved oxygen during the bio‐regeneration mode with untreated river water. Protozoa, worms, rotifers, bacteria, fungi and algae were used as biological parameters. The neural network model could reasonably estimate the chemical oxygen demand reduction in an exhausted filter. The neural network model gave much better results than a second‐order polynomial regression model; however, a much larger database is required than is currently available.

AbstractPhosphorus removal by constructed wetlands is a key strategy in diffuse pollution control. Phosphorus retention by experimental unplanted vertical‐flow constructed wetlands depends on substrate, influent quality and hydraulic residence time (HRT). The maximal phosphorus adsorption capacities of shale, gravel, ironstone and hornblende were 619.7, 89.05, 324.9 and 153.1 mg/kg, respectively, when the grain size ranged between 0.5 and 1.0 mm. Phosphorus adsorption capacities of shale, ironstone and hornblende were best explained by Langmuir adsorption isotherms. In comparison, Freundlich adsorption isotherms fitted gravel well. In separate column experiments with eutrophic Jin River water, shale showed better soluble reactive phosphorus (SRP) and total phosphorus (TP) retention performances than gravel, ironstone and hornblende. When the HRT was 2.2 days, the mean SRP removal rates were 96.7, 21.1, 33.6 and 33.0% for shale, gravel, ironstone and hornblende, respectively. Findings indicate that both SRP and TP removal rates increased when the HRT was prolonged.

Currently, it is important to develop strategic frameworks to support the selection of sustainable resource recovery solutions. This study applies a new framework for planning, implementation, and assessment of resource recovery strategies for a full-scale wastewater treatment plant (WWTP) in São Paulo megacity. The framework comprises several steps based on case study-specific data and information from current literature. Data were collected from various sources: a survey with a wastewater treatment utility, national and regional databases, and review of local regulations and international literature. Treatment configuration, wastewater and by-products composition, potential demand (for water, energy, and phosphorus), stakeholder identification, and local legislation were thoroughly discussed regarding decision-making on resource recovery. Scenario analysis was used to explore suitable nutrient and energy recovery measures based on indicators. Biogas recovery and sewage sludge composting showed more favorable conditions due to similar experiences in the area and robust legislation. The proposed framework is a simplified tool, and its application can support managers to get information on resource recovery and how to plan such initiatives in easier ways to facilitate wiser decision-making, and better operation and management. The results on framework use and refinement can guide potential applications in other contexts and stimulate public policy formulation and further research.