Removal of Cadmium, Lead, Zinc, Copper and Iron from Their Aqueous Solution by Kaolinite Clay

Abstract: Dynamic membrane system behaviour must be adequately addressed to avoid process unfeasibility. The lack of proper analysis will mean relying on erroneous permeate flux values in the system design, which will lead to quick and/or steady high fouling rates. In this paper, the authors present additional data supporting the boundary flux theory as a helpful tool for membrane engineers to carefully avoid process failures. By fitting the dynamic permeate flux data to the boundary flux model, it was possible to calculate the β fouling index for the three selected membranes (one nanofiltration (NF) and two reverse osmosis (RO) ones). The dynamic flux given by the low-pressure RO membrane did not follow sub-boundary operating conditions, since a sharp flux loss was measured throughout the whole operating cycle, pinpointing that supra-boundary flux conditions were governing the system. This was supported by the calculated value of the β fouling parameter, which resulted to be in the order of ten times higher for this membrane. However, the values of β→0 for the SC-RO and DK-NF ones, supported by the very low value of the sub-boundary fouling parameter α (0.002 and 0.007 L·h −1·m−2 ·bar−2 , respectively), ensure nearly boundary operating conditions for these membranes.

Abstract Developing country causes growth of industries sectors. Despite that industrial sectors releases massive amount of waste water into the environment. At the same time, the increasing number of vehicles in Malaysia promotes the development of automobile workshop that produces huge amount of wastewater as well. Wastewater contains high level of suspended total solids and leave untreated. For instance oil, grease, dyestuff, chromium, phosphate in washing products and colouring, as well as heavy metals such as lead, cadmium, barium and others potential metals. All these hazardous wastes directly pollute the environment especially the groundwater and harm the ecosystem. In order to minimize and reduce the impact to the environment, the wastewater needed to be treated using technology such as permeable reactive barrier (PRB). Activated carbon is one of the PRB utilised. It is a compromised material for treatment of wastewater where there are varieties of sources to produce activated carbon. Malaysia as an active agricultural country, massive amount of agriculture wastes can be turned into activated carbon. They are two methods used to produce activated carbon, namely furnace heat processing and microwave processing. The usage of furnace and microwave instruments can produce different quality of activated carbon due to different mechanism involves. Furnace heat processing transferred the heat from external to the internal but microwave processing is vice versa. In this article, a brief overview of activated carbon usage for wastewater treatment is highlighted.

Abstract Industrialization and excessive use of pesticides for boosting agricultural production have adversely affected the ecosystem, polluting natural water reserves. Remediation of contaminated water has been an area of concern with numerous techniques being applied to improve the quality of naturally available water to the level suitable for human consumption. Most of these methods, however, generate by-products that are sometimes toxic. Heterogenous photocatalysis using metal oxide nanostructures for water purification is an attractive option because no harmful by-products are created. A discussion on possible methods to engineer metal oxides for visible light photocatalysis is included to highlight the use of solar energy for water purification. Multifunctional photocatalytic membranes are considered advantageous over freely suspended nanoparticles due to the ease of its removal from the purified water. An overview of water remediation techniques is presented, highlighting innovations through nanotechnology for possible addressing of problems associated with current techniques.

ABSTRACT: This research represents a practical attempt applied to calibrate and verify a hydraulic model for the Blue Nile River. The calibration procedures are performed using the observed data for a previous period and comparing them with the calibration results while verification requirements are achieved with the application of the observed data for another future period and comparing them with the verification results. The study objective covered a relationship of the river terrain with the distance between the assumed points of the dam failures along the river length. The computed model values and the observed data should conform to the theoretical analysis and the overall verification performance of the model by comparing it with another set of data. The model was calibrated using data from gauging stations (Khartoum, Wad Medani, downstream Sennar, and downstream Roseires) during the period from the 1st of May to 31 of October 1988 and the verification was done using the data of the same gauging stations for years 2003 and 2010 for the same period. The required available data from these stations were collected, processed and used in the model calibration. The geometry input files for the HEC-RAS models were created using a combination of ArcGIS and HEC-GeoRAS. The results revealed high correlation (R2 ˃ 0.9) between the observed and calibrated water levels in all gauging stations during 1988 and also high correlation between the observed and verification water levels was obtained in years 2003 and 2010. Verification results with the equation and degree of correlation can be used to predict future data of any expected data for the same stations.

Abstract: The use of water disinfection as a public health measure reduces the spread of diseases. Various disinfection technologies can be used to meet the pathogen inactivation demand in water. This work is an overview of the main disinfection technologies of wastewater and drinking water that reports for the conventional processes the action mechanism, the possible formation of by-products, the operative conditions, the advantages and disadvantages. For advanced and natural processes the action mechanisms are reported. Advanced technologies are interesting but are still in the research state, while conventional technologies are the most used. There is a tendency, especially in Italy, to use chlorine-based disinfectant, despite in some forms could lead to production of disinfection by-products.

Biofouling is a critical issue in membrane water and wastewater treatment as it greatly compromises the efficiency of the treatment processes. It is difficult to control, and significant economic resources have been dedicated to the development of effective biofouling monitoring and control strategies. This paper highlights the underlying causes of membrane biofouling and provides a review on recent developments of potential monitoring and control methods in water and wastewater treatment with the aim of identifying the remaining issues and challenges in this area.