Modelling and simulation of energy-saving potential of Sequential Batch Reactor (SBR) in the abatement of ammoniacal-nitrogen and organics

The ammonical nitrogen removal in discharged effluents from a typical sewerage treatment plant has not been consistent with the stringent discharge standards. There is the need to optimize the energy consumption as well as improve the ammonical nitrogen removal in the treatment plant. This study reports the investigation of the behaviour of process dynamicity of ammoniacalnitrogen (NH3-N) removal in a Sequencing Batch Reactor (SBR) through Activated Sludge Model No.1 (ASM1) and standard SBR design computation for optimal aeration time, while meeting the treatment requirements. Thestudy further evaluates the performance of NH3-N removal based on the data obtained from an existing SBR system. The time profile of process dynamics and the minimum required aeration time with maximum nitrogen removal was studied while taking into account the system’s energy consumption. Moreover, the simulation results by MATLAB Software suggested that the process dynamicity of the carbon and NH3-N concentration is 7 hour batch time with one fill and 1.5 hours aeration time. For computation of SBR standard design, the reduction from current 1.5 hours to 1.35 hours of aeration for 80% to 93% of NH3-N removal brought about the total energy saving of up to 10 percent

Cake compressibility analysis of BPOME from a hybrid adsorption microfiltration process

This study investigates the utility of a hybrid adsorption-membrane process for cake compressibility evaluation of biotreated palm oil mill effluent. A low-cost empty fruit bunch (EFB) based powdered activated carbon (PAC) was employed for the upstream adsorption process with operation conditions of 60 g/L PAC dose, 68 min mixing time, and 200 rpm mixing speed to reduce the feed-water strength and alleviate probable fouling of the membranes. Two polyethersulfone microfiltration (MF) membranes of 0.1 and 0.2 lm pore sizes were investigated under constant transmembrane pressures (TMP) of 40, 80, and 120 kPa. The compressibility factors (z), which was obtained from the slopes of power plots (function of specific cake resistance (a) and pressure gradient) were evaluated. The z values of 0.32 and 0.52, respectively obtained, for the 0.1 and 0.2 lm MF membranes provided compressible and stable z values as observed from their power plots. Besides, these membranes were found suitable for the measurement of z since the results are in consonance with the established principle of cake compressibility. Moreover, the upstream adsorption mitigated the clogging of the membranes which ultimately led to moderate resistances and cake compressibility. These are indications that with the secondary cake filtration, a sustainable flux can be achieved during BPOME filtration. The membranes exhibited close to 100% restoration after cleaning

Removal of organics from treated palm oil mill effluent (POME) using powdered activated carbon (PAC)

In 2011, Malaysia produced more than 16 million tonne of crude palm oil (CPO) with almost 93 million tonne of fresh fruit bunches (FFB) processed. This large amount of FFB processed required very huge amount of water for crude oil extraction which later produced millions tonne of wastewater as palm oil mill effluent (POME). Millions of tons of treated POME are discharged into the water bodies in Malaysia as ‘clean’ waste after anaerobic-aerobic treatment. However, treated POME potentially can become alternative water resource for reclamation and reuse on-site either for plant cleaning or as feed water process. The removal of organics like chemical oxygen demand (COD) and total suspended solids (TSS) in treated POME were studied using commercial powdered activated carbon (PAC) as adsorbent. It shows that the COD and TSS removal were increase as the PAC dosage increases before both reach equilibrium at dosage 2 g. The COD adsorption was best suit with the Freundlich isotherm model and the isotherm model for TSS was suit the Langmuir isotherm with R2 values 0.9742 and 0.9782 respectively

Electrostatic biosorption of COD, Mn and H2S on EFB-based activated carbon produced through steam pyrolysis: an analysis based on surface chemistry, equilibria and kinetics

Biosorption of chemical oxygen demand (COD), manganese (Mn) and hydrogen sulphide (H2S) onto an empty fruit bunch (EFB)–based powdered activated carbon (PAC) from a multicomponent system—biotreated palm oil mill effluent (BPOME)—were studied in a batch adsorption process. The experimental results were fitted to four isotherm models, and four kinetic models. Amongst the isotherm models (Langmuir, Freundlich, Temkin and DubininRadushkevich) employed, Langmuir model showed the best conformity to the equilibrium data with R2 values of 1.00 for COD and 0.9999 for both Mn and H2S. The Dubinin–Radushkevich model followed the conformity trend with R2 values of 0.9984, 0.9948 and 0.9824 for COD, H2S, and Mn, respectively. Also, amongst the kinetic models (Pseudo-first order, Lagergren’s pseudo-second order, Elovich and Weber– Morris intra-particle diffusion) employed, only the pseudosecond order model could best describe the adsorption behaviours of all the three contaminants withR 2 values of 1.00 in all cases. The mechanistic uptake pathway was further examined by means of the Fourier transform infrared in studying the surface chemistry of the PAC. It was observed that the presence of functional groups like the aldehydes andketones, carbonyl, mono-alkyl, amines, amongst others led to physicochemical interactions between PAC surface and the contaminants. Overall, the equilibrium, kinetics and surface chemistry analyses pointed towards the adsorption processes been largely driven by electrostatic sorption. Additionally, the EFB-based PAC was capable of reducing COD, Mn and H2S from POME, hence, could be utilized in developing a unit operation for integration into the current POME treatment. Graphical Abstract Percent uptake versus adsorption time plot for COD, Mn and H2S removal from biotreated POME

Study of the effects of process parameters on electroforced sedimentation in solid–liquid separation using response surface methodology

Electroforced sedimentation (EFS) is a wellknown technique for enhancing the solid content of the final sludge cake. However, the parameters affecting the performance of EFS and quality of the resulting sludge cake, as well as the removed water, are not sufficiently studied. In this research, a mixture of zinc oxide (representing sludge) and polyacrylamide (dewatering aid) were used as experimental materials. The process parameters of electroforced sedimentation were optimized using a design of experiment software (Design Expert Version 7.0.0) with a face-centered central composite design (FCCCD) under response surface methodology. An optimization study was carried out for the output response (sedimentation velocity) based on three process factors and an empirical model was developed. The optimized values for current density, total solid volume per unit cross-sectional area and polyacrylamide dose for the highest sedimentation velocity (0.0199 cm/min) were 6.0 A/m2 , 7.74 mm and 1.53 % (based on the weight of zinc oxide), respectively. The overall model was significant with Prob [F value of 0.0117 and R2 value of 0.8911 while the most significant parameter was observed to be the current density with a Prob [F value of 0.0004. Validation experiments were conducted to confirm and measure the accuracy of the models for the three set of parameters including optimum parameters. The error was within the limit of prediction accuracy, and the sedimentation velocity was enhanced by the addition of 1.53 % PAM as dewatering aid. Thus, it was concluded that EFS can be applied successfully for materials having permanent charge

Comparative and optimization studies of adsorptive strengths of activated carbons produced from steam- and CO2-activation for BPOME treatment

This study basically compared the adsorptive efficacies of powdered activated carbons (PACs) produced from palm empty fruit bunches (EFB) in the treatment of a non-simulated biotreated palm oil mill effluent (BPOME). Each of the PACs was produced from two different methods namely steam- and CO2-activation routes. This test was performed with the main aim of obtaining an appropriate activated carbon suitable for the treatment of BPOME. The steam activated PAC was found to possess higher adsorptive strength as compared with that of CO2 activation with the operating conditions of 150 rpm agitation for 60 min with varying dosage of PAC from 0.5 – 5.0 g. The steam activated PAC performed better than the CO2 activated PAC with a record uptake of up to 81%, 92% and 89% for Chemical Oxygen Demand (COD), Manganese (Mn) and Hydrogen Sulfide (H2S) respectively as compared with the uptake of 67%, 90% and 87% from the CO2-activated PAC. Furthermore, a 2-level full factorial design of experiment was utilized to assess the effects of three factors on adsorption. The highest removal efficiencies for COD, Mn and H2S were found to be 83.1%, 93.6% and 89.8% at adsorbent dosage 5 g, agitation speed 200 rpm and contact time 60 min

Study of graphene oxide-polymer nanocomposite (GPN) adsorptive membrane for lead removal from wastewater

The utilisation of polymeric membrane has been reported in numerous investigations on wastewater management of heavy metals. In this work, graphene oxide-polymer nanocomposite (GPN) adsorptive membranes were fabricated via non-solvent induced phase inversion (NIPS) method for lead removal. The modification of polyethersulfone (PES) membrane was conducted by incorporating graphene oxide (GO) in the matrix polymer solution. The characterisation of the GPN membranes were investigated through porosity, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Optimisation of batch adsorption experiments on the GPN membrane fabricated with 0.5 wt.% of GO with the addition of 0.5 wt.% of polyvinylpyrrolidone (PVP) exhibited the highest lead removal that is about 97.81% under 60 minutes exposure and acidic condition (pH 5). Langmuir isotherm model was found to be the best-fitting for the lead adsorption process. The findings indicated that the monolayer adsorption mechanism occurred on the surface of the GPN membrane

A two-step optimization and statistical analysis of COD reduction from biotreated POME using empty fruit bunch-based activated carbon produced from pyrolysis

In this investigation, the potential of powdered activated carbon (PAC) derived from empty fruit bunch (EFB) precursor through pyrolysis method for chemical oxygen demand (COD) adsorption from biotreated palm oil mill effluent (POME) was extensively studied. The PAC was prepared and characterized using scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy and Brunauer–Emmett–Teller. The SEM microphotographs showed opened micropores existing in the PAC structure with a surface area of 886.2 m 2 /g. The FTIR spectra revealed the three major peaks exhibited by the surface of the activated carbon at exactly wavenumbers of 1737.61, 1365.10 and 1216.91 cm -1 . This suggests the presence of some functional groups which can potentially enhance positive interactions between the adsorbent and the adsorbate.Design-Expert � software (version 7.0.0) was employed for the statistical experimental design of a twostep optimization: factorial and response surface methodology. Maximum COD reduction of 84 % (227 ppm residual) was achieved from an initial concentration of 1387 ppm. This study being the first optimization process with the utility of EFB-based PAC in the treatment of the high-strength multicomponent biotreated POME; hence, the results could serve as requisite data for upscaling and/or future investigations in the utility of the precursor as a viable adsorbent

Treatment of biotreated palm oil mill effluent using powdered activated carbon produced from palm empty fruit bunch

Powdered Activated Carbon (PAC) was produced from empty fruit bunch (EFB) precursors by CO2 activation at 800¬0C, N2 (2.5 L/min) for 30 mins and CO2 (0.1L/min) for 15 mins. Batch adsorption was conducted using Biotreated palm oil mill effluent (BPOME) under various conditions such as agitation (100 – 200 rpm), dosage (5 – 10g) and contact time (30 – 60 mins). The maximum Chemical Oxygen Demand (COD) removal was 56.6% at the operating conditions of 10 grams, 200rpm and 30 mins contact time. Improved production conditions of PAC from EFB is expected to improve the adsorption capacity, however its availability and renewable sources indicates its prospect as a cost-effective adsorbent for industrial applications. In general, it is shown that EFB-PAC could be employed as an effective and less expensive adsorbent for the reduction of COD in BPOME. This study further supports waste to wealth and zero waste discharge policy

Morphological synthesis and environmental application of ZSM-5 zeolite crystals from combined low-water and fluoride syntheses routes

ZSM-5 crystals have been morphologically prepared through the combination of Fluoride and Low-Water Synthesis Routes. This was done in order to bring about larger zeolite crystals with high Si/Al ratio and surface area suitable for environmental applications. The zeolite was analyzed to have crystal size between 200 – 218μm with a micropore volume of 0.79cm3/g. It was also found to possess a Si/Al ratio (SAR) of 194.4 with good adsorption and catalytic prowess when analyzed by SEM and XRD. The prepared zeolite was employed in the petroleum refinery wastewater treatment to evaluate its organic and inorganic removal efficacies as evident from the Chemical Oxygen Demand (COD) and Iron (Fe) contents adsorption where it exhibited 99% and 98% efficiency removal respectively