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

Equilibrium modeling, kinetic and thermodynamic studies on the adsorption of basic dye by low-cost adsorbent

In this study, the removal of methylene blue (MB) dye from aqueous solutions using low-cost material as adsorbent by a batch system was investigated. Experiments were carried out as a function of contact time, initial concentration (50-300 mg/L), pH (2-12) and temperature (303-323K). The equilibrium adsorption of MB dye on petai (Parkia speciosa) seed adsorbent was analyzed by Langmuir and Freundlich models. The results indicate that the Freundlich model provides the best correlation of the experimental data. The adsorption capacities of the petai seed adsorbent for removal of MB dye was determined with the Langmuir equation and found to be 91.74, 94.34 and 100.03 mg/g at 303, 313, and 323 K, respectively. The kinetic data was found to follow closely the pseudo-second-order model. Various thermodynamic parameters such as enthalpy (ΔH°), entropy (ΔS°) and free energy (ΔG°) were evaluated. The positive value of the enthalpy change (17.89 kJ/mol) indicates that the adsorption is endothermic process. The results indicate that petai seed adsorbent is suitable as adsorbent material for adsorption of MB dye from aqueous solutions

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

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

Anaerobic Fluidized Bed Reactor (AFBR) for the treatment of high solid content agro-industrial wastewater

Palm oil mill effluent (POME) is a high strength agro-industrial wastewater that contains significant amount of organic suspended solids. These solids reduce plant efficiency and account for additional maintenance of fixed bed digesters. An anaerobic fluidized bed reactor was studied to evaluate the performance of the system to treat solids from the POME. The hydraulic retention time (HRT) was reduced step wise from 24 hr to 4 hr, which resulted in volumetric loading rates of 4.0 kg COD/m3.d to 13.8 kg COD/m3.d, respectively. The maximum TSS removal rates varied in the range of 68% - 89%. The AFBR showed promising performance without exhibiting any problem pertaining to the solids in the wastewater. The AFBR exhibited low sludge production with sludge volume indices (SVI) of between 11 L/mg and 35 L/mg. The low SVI indicates fast settleability and self-compressibility of the digested solid particles in POME. The study showed the superiority of AFBR over the other treatment processes in treating industrial wastewater that contains significant portion of solids

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

An integrated technique using solar and evaporation ponds for effective brine disposal management

Desalination is a process that involves the removal of salts and non-ionic minerals from seawater to produce freshwater that is fit for human consumption. This process produces brine, which is typically redisposed into the sea. The relatively high salt concentration in the disposed brine increases the salinity of water and soil, which adversely affects the environment. However, brine is found to be rich in economically valuable minerals. In order to effectively manage the disposed brine, this study proposes an integrated technique using solar and evaporation ponds to filter valuable minerals from concentrated brine. The results of this study demonstrate that the proposed technique can be effectively employed for this purpose. Furthermore, this helps reduce desalination costs and complies with the notion of renewable energy production and eco-friendliness