Waste management: what is the choice: land disposal or biofuel

Many cities in developing Asian countries are facing serious problems in managing their municipal solid wastes as annual waste generation increases in proportion to the rise in population and urbanization. Asian countries with greater rural settings produce more organic waste such as kitchen wastes and less of recyclable items such as paper, metals and plastics. The method of disposing wastes using landfill poses a serious environmental threat which requires innovation and more research has to be carried out to solve this issue. New challenges faced by local authorities are related mainly to finding the best option for managing the problems and costs of collection and disposal of solid wastes in a growing city. With the global scenario of escalating cost of fuel prices, municipal solid waste is seen as a potential resource for our renewable energy project. There is growing interest in the utilization of solid waste as biofuel to produce electricity. Various technologies in converting the waste material into biofuel are made available, which may change the landscape of today’s waste management, from landfill disposal to resource recovery.Biofuel economy has steered our thoughts towards the conversion of such unwanted materials into valuable energy feedstock, which the world is now seriously moving towards. With the emergence of new technologies for conversion of wastes into biofuel, be it biomass or biogas, the options are now very clear. The Biofuel option can be the best strategy as long as our policies are targeted toards achieving sustainable development as the ultimate goal

Ultrasonication effects on ultrafiltration membrane cleaning and fouling mitigation

Mitigation of fouling on hollow fiber ultrafiltration membrane using ultrasonication has been carried out. The effects of different contact times, at constant frequency and power of 28 kHz and 60 Watt, respectively on membrane cleaning with and without chemical agents were studied. Results showed that the best optimal membrane cleaning achieved were sonicating in 15 minutes without any chemical agents, with 57% recoveries.It should be noted that the presence of the chemical agent increased the effectiveness of ultrasonic cleaning compared to using water. The best combination method recovered the initial flux to at 67% using 1M of NaOH and 10 min sonication. This is likely the consequence of expanded cavitations movement occurring in the more surface-dynamic result

Organic dye adsorption on activated carbon derived from solid waste

Activated carbon was prepared through a chemical activation of bamboo waste precursor (BMAC) using phosphoric acid as the activating agent at 500°C for 2 h. Batch adsorption studies were carried out for the adsorption of C.I. Reactive Black 5 (RB5) onto the BMAC. The effect of various experimental parameters such as initial dye concentration (50–500 mg/L), contact time (0–32 h), pH (2–12), and temperature (30–50°C) were investigated. Equilibrium data were found to be very well represented by the Freundlich isotherm and a pseudo-second-order model was found to explain the kinetics of RB5 adsorption more effectively. The mechanism of the adsorption process was determined by the intraparticle diffusion model. Thermodynamic parameters such as standard enthalpy (ΔH°), standard entropy (ΔS°), standard free energy (ΔG°), and activation energy were determined. The results indicated that BMAC is a suitable adsorbent material for adsorption of reactive dye from aqueous solutions

Numerical studies of fluid flow across a cosmo ball by using CFD

Cosmo ball is a media used in wastewater treatment to increase the surface area of contact and provide longer contact time for biological activities. It is usually placed as a media or as packing in the aeration tank, BioFil tank or even in the activated sludge tank. It induces the growth of bacteria on its surface, which will serve as a contact area for the wastewater and the microbial. The objective of this simulation is to analyze the flow pattern around the Cosmo ball which is been packed in the wastewater treatment tank. By conducting this analysis, the overall insights on the interaction of the fluid flow with the Cosmo ball surface can be visualize. The velocity of the fluid flow across the ball is at a speed of 2 cm sec-1. The velocity was obtained from the conventional wastewater treatment plant. During the simulation process, the model will undergo each section of program in ANSYS™ Computational Fluid Dynamics (CFD) such as Design Modeler, Meshing, Pre-Processing, Solver and Post-Processing. The flow distribution across the Cosmo ball was analyzed by varying the angle of attack of the flow. The rationale for this simulation arrangement is that the ball could take any orientation in the bulk media and the fluid flow across it would be at random angle. The result shows that the flow around the Cosmo ball was dispersing sideways thus inducing mixing in the wastewater system. Retention of flow has been observed to occur in the Cosmo ball. The retention of flow provides better microbial interaction with the wastewater

Hazardous effect of raw sewage disposal from indigenous housing settlement on natural water bodies

One of the problems that are causing a threat to public health is a sanitation system of indigenous houses built on water. The traditional way of life of indigenous society living in housing settlements over rivers or the sea is becoming a source of environmental pollution. These houses did not actually have a proper sanitation system for disposing wastes from toilets. The sanitation systems for these houses unfortunately dispose wastes directly into natural water bodies. The centralization of the waste disposal may cause problem to the public due to technical and financial different faced by the authorities. This research requires gathering relevant data source based on direct observation and indirect observations. Also this project will utilize on qualitative data collection tools, but is rooted in a qualitative epistemological position that recognizes the importance of locating the research within a particular social, cultural, and house settlement. This paper surveys the literature on problems that arise from raw sewerage disposed into natural water bodies before any sanitation is proposal to solve the problem. Also the potential solutions to the problem were discussed too

Review on biofilm processes for wastewater treatment

This review paper discusses the application of biofilm as an alternative technology for the treatment of wastewater under various loading and operation conditions. In the past few years the biofilm technology has become more common and widely used in the world to meet the requirement for clean water sources of the world’s growing population. Besides, the conventional wastewater treatment plants like activated sludge process present some shortcomings such as not very flexible method (if there is sudden change in the character of sewage and the effluent of bad quality is obtained), so better system is urgently needed to provide additional capacity with the least possible cost and to meet the standard effluent by the local authorities. The increased incoming flow of wastewater to the treatment plants and organic loading always demand for additional treatment capacity. Fundamental research into biofilm is presented in this paper in sections that discuss the use of biofilm whereby a comparison between suspended and fixed film, old and new biofilm are made. Besides, bed types namely moving bed, fixed bed and floating bed, un-submerged fixed film systems of trickling filters and rotating biological contactors are explained. Nutrients removal of nitrogen and phosphorus and nano technology application in biofilm are also explained. Results from investigations of different applications carried out at the laboratory and pilot scales are also discussed

Runoff quality index for area under maize cultivation

Land development activities contribute to water quality impairment. The resulting runoff from rainfall from different land use areas carries a wide range of pollutants that find their ways to the surface and ground waters. The use of models plays an important role in the assessment of diffuse pollution sources and their delivery to the receiving water bodies. The current Water Quality Index (WQI) used by the Department of Environmental (DOE) Malaysia has limitations when applied to agricultural areas. The important parameters do not include those pollutants particular to agricultural areas. This research project was carried out on sandy clay loam soil grown with maize (Zea Mays). The experimental plot was isolated from the surrounding areas with perimeter bunds to protect from runoff from adjacent areas. Thirty seven rainfall events in three seasons were monitored to evaluate the parameters that contributed most to the Non-point Source (NPS) pollution. A Runoff Quality Index (RQI) was proposed to assess runoff quality. The quality parameters include Total Kjeldhal Nitrogen (TKN) and Total Phosphorous (TP). It must be mentioned that the results of this experimental study is limited specifically to an agricultural area that was cultivated in maize only