Urban Wastewater Treatment by Adsorption of Organic Matters on Modified Bentonite by(Iron-Aluminum)

In this research, the natural bentonite clay (from Maghnia, western Algeria) was purified (Na+- montmorillonite, CEC = 91 meq/100 g), noted (puri.bent) and modified with mixed hydroxy-Fe-Al (FeAl-PILC). The purified bentonite clay and FeAl-PILC were heated at 383 K for 2 hr and characte-rized by the chemical analyses data, XRD, and N2 adsorption to 77 K techniques. Puri.bent and FeAl-PILC were applied to fix the organic matter (OM) present in urban wastewater from the city of Sidi Bel-Abbes (western Algeria). The adsorption of organic matter was followed by spectro-photometry at 470 nm, and the adsorption data were a good fit with Freundlich isotherm for pu-ri.bent but for FeA-lPILC, were well fit by Elovitch isotherm model. The maximum adsorption ca-pacity (qm) was 571.6 mg/g for puri.bent and 1120.69 mg/g for FeAl-PLC. The degree of OM removal was 67% for puri.bent and 97% for FeAl-PILC. FeAl-PILC can be considered as a promising adsorbent for the removal of OM from wastewater.

Greywater reuse as a key enabler for improving urban wastewater management

Sustainable water management is essential to guaranteeing access to safe water and addressing the challenges posed by climate change,urbanization,and population growth.In a typical household,greywater,which includes everything but toilet waste,constitutes 50e80%of daily wastewater generation and is characterized by low organic strength and high volume.This can be an issue for large urban wastewater treatment plants designed for high-strength operations.Segregation of greywater at the source for decentralized wastewater treatment is therefore necessary for its proper management using separate treatment strategies.Greywater reuse may thus lead to increased resilience and adaptability of local water systems,reduction in transport costs,and achievement of fit-for-purpose reuse.After covering greywater characteristics,we present an overview of existing and upcoming technologies for greywater treatment.Biological treatment technologies,such as nature-based technologies,biofilm technologies,and membrane bioreactors(MBR),conjugate with physicochemical treatment methods,such as membrane filtration,sorption and ion exchange technologies,and ultraviolet(UV)disinfection,may be able to produce treated water within the allowable parameters for reuse.We also provide a novel way to tackle challenges like the demographic variance of greywater quality,lack of a legal framework for greywater management,monitoring and control systems,and the consumer perspective on greywater reuse.Finally,benefits,such as the potential water and energy savings and sustainable future of greywater reuse in an urban context,are discussed.

An integrated model for structure optimization and technology screening of urban wastewater systems

The conventional approach to wastewater system design and planning considers each component separately and does not provide the optimum performance of the entire system. However, the growing concern for environmental protection, economic efficiency, and sus- tainability of urban wastewater systems requires an integrated modeling of subsystems and a synthetic evaluation of multiple objectives. In this study, a multi- objective optimization model of an integrated urban wastewater system was developed. The model encom- passes subsystems, such as a sewer system, stormwater management, municipal wastewater treatment, and a wastewater reclamation system. The non-dominated sort- ing genetic algorithm （NSGA-II） was used to generate a range of system design possibilities to optimize conflicting environmental and economic objectives. Information from a knowledge base, which included rules for generating treatment trains as well as the performance characteristics of commonly used water pollution control measures, was utilized. The trade-off relationships between the objec- tives, total water pollution loads to the environment, and life cycle costs （which consist of investment as well as operation and maintenance costs）, can be illustrated using Pareto charts. The developed model can be used to assist decision makers in the preliminary planning of system structure. A benchmark city was constructed to illustrate the methods of multi-objective controls, highlight cost- effective water pollution control measures, and identify the main pressures on urban water environment.

Examination of the Level of Heavy Metals in Wastewater of Bandar Abbas Wastewater Treatment Plant

One of the main environmental pollutants is heavy metals. Due to extensive usage in industry, these metals enter biological cycle rapidly and contaminated water and soil resources rapidly. In this work, lead, copper, zinc and chromium of Bandar Abbas wastewater are examined. For this research, nine stations were set for measurement in urban level in Bandar Abbas and sampling of aforesaid metals was performed in fall and winter 2006 in these stations. After extraction and preparation operations using APDC-MIBK, samples were measured using flame atomic absorption system. According to results, concentrate of studied metals was lower than allowable standard value set by Iran environmental protection organization for agricultural purposes and sewage to ground level waters. In addition, efficiency of Bandar Abbas wastewater treatment plant to remove these metals is 40% - 70% from which highest removal is for zinc as much as 71.1% and lowest level is for copper as much as 40.5%. However, copper level was higher than allowable level for agricultural purposes in spring and summer (0.21 mg/L and 0.23 mg/L, respectively) and lower in fall and winter (0.103 mg/L and 0.098 mg/L, respectively). Furthermore, changes in concentration of metals in these stations in various seasons were measured and analyzed using one-way variance analysis and simultaneous effects of time and place on measured variables were analyzed using two-way variance analysis.

Wastewater reclamation and reuse in China:Opportunities and challenges

The growing water stress both in terms of water scarcity and quality deterioration promotes the development of reclaimed water as a new water resource use. This paper reviewed wastewater reuse practices in China, and the opportunities and challenges of expanding reclaimed water use were analyzed. Rapid urbanization with the increasing of water demand and wastewater discharge provides an opportunity for wastewater reuse. The vast amount of wastewater discharge and low reclaimed water production mean that wastewater reuse still has a great potential in China. Many environmental and economic benefits and successful reclamation technologies also provide opportunities for wastewater reuse. In addition, the overall strategy in China is also encouraging for wastewater reuse. In the beginning stage of wastewater reclamation and reuse, there are many significant challenges to expand wastewater reuse in China including slow pace in adopting urban wastewater reuse programs, the establishment of integrated water resources management framework and guidelines for wastewater reuse programs, incoherent water quality requirements, the limited commercial development of reclaimed water and the strengthening of public awareness and cooperation among stakeholders.