Ahmed Kettab

On modeling chronic detachment of periphyton in artificial rough, open channel flow

Abstract Periphyton communities, which are native to river beds, serve as a functional indicator of river health but remain one of the least-studied communities despite the significant increase in the examination of aquatic microbial communities in recent years. In this study, we tested the relevance of three formulations of the chronic detachment term in a simple model for the biomass dynamics of periphyton. Numerical simulations of the periphyton biomass dynamics were performed by using three different descriptors for the flow conditions: the discharge Q, the friction velocity u ∗, and the roughness Reynolds number k+  = u ∗ k s/ν (where ν is water kinetic viscosity and k s is the Nikuradse equivalent sand roughness). Comparisons of numerical simulation results with experimental data from literature revealed chronic detachment to be better simulated by taking the roughness Reynolds number as the external variable of detachment. These results support the idea that transport phenomena that occur in the ne...

Study of the prospects for agricultural utilization of sludge produced from WWTPS in North Central Algeria

The objective of this study is to investigate the sewage sludge of six wastewater treatment plants (WWTPs) in North Central Algeria for agricultural reuse. After a brief description of the region (climate, distribution of soils, and crop types), a quantitative and qualitative examination of the sludge produced was conducted in addition to a comparative study of urban compost and cattle manure. The selected agronomic parameters were dryness, percentage of organic matter (OM), as well as the contents of nitrogen, phosphorus, potassium, and calcium. An average OM of soils of 1.3% and a minimum value of 0.2% made it clear that the urgency of providing this type of amendment was warranted. The sewage sludge in this study was characterized by carbon to nitrogen ratios lower than those of manure and compost due to its stabilization process at the WWTPs on one hand, and the presence of recalcitrant lignin compound mineralization in compost and manure, on the other hand. The spreading of sludge in the region covered a very small surface area, not exceeding 0.50% of the overall agricultural area. The quantities of fertilizers produced by sludge were significant and often exceeded agricultural requirements. Yet, due to the insufficient amounts of OM provided by sewage sludge, there was a need to rely on alternate sources such as manure and/or urban compost.

Water for all with quality and quantity: it is the concern of all!

In a situation of increasing scarcity of water supply and problems related to climate change, many international organizations such as the UN, UNESCO, Plan Blue, the World Water Council, Agenda 21 and UNEP are deeply concerned about establishing sustainable management policies and governance rules on water resources to ensure sustainability of this vital resource. An optimal economy can be achieved only by ensuring a rational use of water essential for meeting the demand of water for industrial, agricultural and domestic uses of an increasing population. It is now widely recognized that the implementation of a sustainable development requires putting into the equation all of the social, economic and environmental concerns considering water as a fundamental and limited element. Climate change brings extra water stress since the issues raised concerning floods, droughts, rising sea levels, etc. in addition to all debates on climate change are in fact deep concerns about water and its natural cycle. Water, a natural resource, which is becoming scarcer, is part of any nation’s heritage as well as the world’s common concern. Its protection, valorization and the development of the resources to be used in the context of natural balances are therefore of general interest both nationally and internationally. We must consider water as a social and economic resource to which access is the right of every individual. Water is essential to humans in particular and to life in general. It has always played an important role in the history of humanity and the development of civilization. It is the source of life, but also may become a source of conflict in many parts of the world. In the twenty-first century, water has become a major issue, and only the nations that have managed to preserve their moisture capital will be able to survive. Countries around the Mediterranean Sea are under semi-arid conditions and are expected to be increasingly faced with water shortages as a result of increasing agriculture, industry and populations, which are growing steadily. In this context, water has a special socio-economic, environmental and geopolitical value. In fact, technical and economic solutions require solidarity between regions and states. Sustainable management of water must also, first of all, take into account some security questions for which agreements and conventions are fundamental requirements. A sustainable approach to the solution of water problems superimposes some innovative and global solutions that can be achieved only by interdisciplinary teams jointly working in networks. The growing importance of water scarcity worldwide requires strengthened cooperation and unification of thought for a sustainable, efficient and equitable management of scarce water resources, whether locally or internationally. The effectiveness of this sustainable management and at the same time the focus on the given value to water quality for health as well as issues of access to clean water for a sustainable environment show the magnitude of the task. During three days of an intensive scientific and technical programme, the WATMED6 conference was rich, diverse and multiand interdisciplinary, led by high-level speakers in multiple sessions. It was an opportunity for discussion and exchange of views between academic communities, researchers, industrialists, politicians, managers, elected officials and policy-makers on current and future subjects concerning to the following topics: Desalination and Water Treatment www.deswater.com

Characterization of byproducts from wastewater treatment of Medea (Algeria) with a view to agricultural reuse

AbstractIt is imperative for Algeria by virtue of its arid to semiarid climate to rationalizing the use of conventional water resources. That is why the agricultural reuse of byproducts is an alternative treatment expected to preserve the water resources, the environment and the promotion of the agricultural sector. The present work aims to search for the possibility of reusing treated wastewater and sludge resulting from the treatment plant of the city of Medea in agriculture, through the analysis of physical, chemical and bacteriological on the samples, and the continuous monitoring of the evolution of several elements. The results showed that the treated water, despite its high salinity, can be reused for irrigation of some salt-tolerant species and on well-drained soil and leached. The sewage sludge, by the relatively low amount of organic matter it contains, is considered a fertilizer, more than organic amendment.