A new method for the analysis of combined operation of electro-osmotic dewatering and mechanical expression

Electro-osmosis is especially effective in removing liquid from sludge of colloidal particles for which conventional mechanical dewatering is not very successful. This work presents results of experimental work carried out to study and analyze the combined operation of electro-osmotic dewatering (EOD) and mechanical expression (ME) by use of the Terzaghi-Voigt combined model for considering creep deformation of the material. The EOD-ME process combines the advantage of electro-osmosis and mechanical dewatering and consequently results in reduced void ratio compared to individual operation

State of the art and recent progresses in water and wastewater treatment

Wastewater collected from municipalities and communities must ultimately be returned to receiving waters or to the land or be reused. Water is a limited resource in the earth’s closed ecosystem. With the world population growing rapidly at very alarming rate, the demand for water is expected to increase in multiple progression and therefore, investigation of alternative methods for preparation of high quality water is necessary. The increasing pressures on water supply and the problems of municipal wastewater disposal can be solved by water reuse. Currently, the concept of deriving beneficial uses from treated municipal wastewater through water reclamation is receiving an increasing attention. Increased water shortages and waterway pollution are major problems posing risks to freshwater resources, with the highest risk from the industries. Wastewater effluent contaminated with heavy metals originating from numerous human and industrial activities is one of the major threats to the environment. In this keynote talk state of the art in water and wastewater treatments will be discussed. Recent progresses in our centre, bioenvironmental research centre here in Malaysia will also be highlighted. These include a new natural, environmentally friendly, safe, and sustainable phytodisinfectant from Moringa oleifera seed for water and wastewater treatment, Electrocoagulation (EC) which is a simple, environmentally friendly and cost effective process, when integrated with membrane filtration, very attractive for developing a sustainable water reclamation system. The other approach is the reclamation of biotreated palm oil mill effluent (BPOME), applying a developed hybrid adsorption-membrane process to produce boiler-feed water for low-pressure operating industrial boilers. Also the removal of heavy metals from industrial wastewater effluent by adsorptive membrane with the dual function of adsorption and filtration process using nanomaterial of graphene oxide (GO). Modeling of electroosmotic dewatering (EOD) of various materials including sludge. Finally the application of artificial intelligence (AI) technology in water and wastewater treatments for performance analysis and prediction will be indicated as tools necessary to the future chemical engineers

Efficient method for the purification of coagulated sewage secondary effluent

Constant rate microfiltration experiments are conducted in purification of sewage secondary effluent pretreated with polyaluminum chloride (PAC). Monolithic ceramic membrane having a nominal pore size of 1.0 micro meter with 19 tubular channels is used as a filter medium. The system is capable of selecting the required mode of membrane cleaning, i.e., physical backwashing or chemically enhanced backwashing, based on the set value of the operating parameters. Flow resistance resulted from the formation of the filter cake is reduced by the physical backwashing, but in spite of this, the flow resistance increases gradually in a longer period of operation due to irreversible pore blocking. Hence chemically enhanced backwashing should be conducted occasionally. Sodium hypochlorite is used as cleaning agent and it is injected automatically when pore blocking reached to the preset level. The experimental results showed that the chemically enhanced backwashing is effective in restoring the increased portion of the flow resistance. The fully automatic system was found to be stable regardless of the variable influent quality and could be run at relatively higher flux of 3.0 m/d for a long period of time. The filtrate is free from pathogens and can be reused as reclaimed water for toilet flushing, car washing, etc. Furthermore, the results obtained under various operating conditions indicated that when process optimization is considered, there should be a trade off between the energy consumption and the amount of cleaning agent used per net filtrate volume

Extraction and screening of various hydrolases from Malaysian channel catfish (ictalurus punctatus) viscera

Malaysia is a large producer of fish industry estimated to be 1.5million tonnes every year. 35-50% of the fish weight is its viscera, which is usually disposed into the landfills or sea leading to massive environmental problems. However, various hydrolases can be extracted from this highly potential by-product source. In this study, protease, lipase, α-amylase and cellulase activities were studied. Protein concentration of the whole viscera of Ictalurus punctatuswas 0.798596 mg/mL, protease gives the highest specific activity among the hydrolases (13.57 U/mg), cellulase was (1.43 U/mg), lipase (1.425 U/mg) and the α-amylase was (0.689 U/mg)

Advances In antifouling strategies in crossflow ultrafiltration: a brief review

This study briefly reviews the recent advances in membrane and separation technology for antifouling strategies for membrane ultrafiltration. Membrane fouling is inevitable in ultrafiltration due to the eventual membrane pore blockage with foulants. Consequently, flux declines and affects the membrane integrity over time along with elevation in processing time and thereby complicating the overall membrane maintenance. To combat this issue, several studies had been undertaken such as grafting of TiO2 nanotubes (TNTs), graphene oxide nanosheets, zwitterions or polymers in the membrane and also by applying direct current. Moreover, many researchers emphasized on the integration of an enhanced pre-treatment process such as adsorption, coagulation, electrocoagulation and so on. By critically analysing and comparing the existing studies, the impact, suitability, efficiency and sustainability of the antifouling strategies will be discussed in this review. This refined approach of observing the progress in membrane technology will enable the determination of the existing gaps in the studies and will help to expand and propel the field further in separation efficiency

Chemical treatment of palm oil mill effluent (POME) from aerated pond

The production of palm oil results in the generation of huge quantities of polluting wastewater commonly known as Palm Oil Mill Effluent (POME). POME is a thick brownish liquid that contains high amount of total solids, oil and grease, chemical oxidation demand (COD), biochemical oxygen demand (BOD), and if not properly treated, can disrupt the natural ecosystem and pose a serious threat to human health. However, with the stringent regulations on discharge of waste into the environment, there is need to retrofit the existing biological system by adding tertiary treatment in form of coagulation to remove contaminants in order to meet the current discharge regulations. This paper compares the use of coagulants ferric chloride and aluminium sulphate to reduce turbidity that is associated with the effluent. Series of batch coagulation and flocculation processes with ferric chloride and aluminum sulphate under different conditions, i.e. dosage and pH were conducted in order to determine their optimum conditions. Polyacrylamide was used as coagulant aid and its optimum dose was also determined. The result of the coagulation process showed that ferric chloride gave a better reduction of turbidity at dosage of 100mg/L, pH of 8 and with polyacrylamide (coagulant aid) dose of 100mg/L than alum

Constant pressure expression of power law non-Newtonian fluid/solid mixture

Expression of non-Newtonian fluid/solid mixture is often encountered in the fields of polymer and food industries. However, a reliable method for the design of the expression process has not been established. In this study, we conducted expression experiments of power law non-Newtonian fluid/solid mixture under constant pressure condition. The basic consolidation equation was derived by combining the fundamental equation for power law non-Newtonian flow through the cake with the equation of continuity and solved numerically using the Runge-Kutta method. The progress of the expression is represented by an average consolidation ratio Uc. The agreement between calculated and experimental Uc was satisfactory when the creep deformation of the material was taken into consideration. It was also elucidated that the consolidation time required for attaining a certain degree of primary consolidation depends on the (N+1)/N-th power of the total volume of the solid material omega_0, where N is the flow behavior index of the squeezed liquid. On the other hand, the creep constants B, the ratio of creep deformation to the total deformation, and eta, a measure of the rate of creep deformation, both were found to be omega_0-independent parameters, supporting the validity of the assumption made in the theoretical derivation

Novel method for gelatin extraction of various local fish using High Pressure Processing (HPP)

Gelatin from fish skin is known to be an alternative source for mammalian gelatin. However, it has weaker properties compared to bovine and porcine gelatin, which limits its use in the industry. The conventional method for fish gelatin extraction requires long production time and could cause serious water pollution and chemical treatments are often being used to enhance the yield of fish gelatin and its properties but it may affect the amino acid content of the gelatin. In this regard, High-Pressure Processing (HPP) is a novel method suggested for fish gelatin extraction. The HPP method is classified as green technology as it requires low electricity throughout the process. This study will discuss the impact of HPP the technique gelatin extracted from fish skin. Skins from four types of fish, namely red tilapia (Oreochromis niloticus), black tilapia (Oreochromis mossambicus), grouper (Epinephelus areolatus) and threadfin bream (Nemipterus tambuloides), were used. High pressure was applied at either pre-treatment in citric acid solution or during thermal extraction; and the pressure was maintained at 250 MPa with pressure holding time of 10 minutes and 18 hours of water extraction. Gelatin extract from traditional acid-base method was prepared as a standard for comparison. The study found that there was an increment in the yield of gelatin and the concentration of gelatin extract, and the pre-treatment time was also reduced

Tertiary treatment of biologically treated palm oil mill effluent (POME) using UF membrane system: effect of MWCO and transmembrane pressure

This study evaluate the performance of ultrafiltration UF membrane system in the treatment of biologically treated palm oil mill effluent (POME) by varying the effects of transmembrane pressure and using different molecular weight cut-off (MWCO). Flat sheet polyethersulfone (PES) ultrafiltration membrane of molecular weight cut-off (MWCO) 1 kDa and 5 kDa were used in this study. Biologically treated POME was subjected to physical pretreatment processes, consisting of coagulation and adsorption to remove total suspended solids. Transmembrane pressure was varied between 0.5 bar to 1.5 bar and the performance of these membrane systems were assessed in terms of reduction of chemical oxygen demand (COD), color and turbidity in POME. Pretreatment processes which consist of coagulation and adsorption showed remarkable results in reducing COD, color and turbidity up to 92.8 %, 99.3 % and 99.9 % respectively. At transmembrane pressure 0.5 bar, more reduction in COD, colour and turbidity were observed. The smallest MWCO of the membrane at transmembrane pressure 0.5 bar gave a better reduction of pollutants from the pretreated POME. The increasing transmembrane pressure leads to a corresponding increase in permeate flux which starts to level off at higher transmembrane pressures. The application of membrane separation technology to treat biologically treated POME has improved the quality of the final effluent discharged. The UF membrane plays very important role in reducing pollutants present in biologically treated POME