Ezerie Henry Ezechi

Treatment of Wastewater Using an Integrated Submerged Attached Growth System

The performance of a single sludge integrated attached growth system comprising of an aerobic and anoxic tanks in biological nutrient removal was evaluated in treating synthetic wastewater simulating medium strength domestic wastewater. An aero-packer and bio-balls were installed in the aeration and anoxic tank occupying about 40% and 25% of both tanks respectively. The efficiency of the integrated attached growth system was evaluated on the removal of chemical oxygen demand (COD), ammonia removal (NH3), nitrate removal (NO3), total suspended solids removal (TSS) and biochemical oxygen demand removal (BOD5). Effluent results show that the integrated attached growth system had a removal efficiency of 97.8% (COD), 97.5% (NH3), 87.5% (NO3), 97% (TSS) and 97.1% (BOD). These results support the viability of an integrated system in mitigating the enormous challenges of a conventional wastewater treatment.

Removal of methylene blue from dye effluent using ageratum conyzoide leaf powder (ACLP)

Methylene blue (MB), a common environmental pollutant discharged from dye effluents were removed from synthetic effluents in this study using ageratum conyzoide leaf powder. Effects of operating parameters such as pH, initial Methylene blue concentration, adsorbent weight and contact time were examined on methylene blue removal whereas stirring speed was constant at 100 rpm. Results show that low pH (3-4) had more Methylene blue removal than high pH. Methylene blue removal decreased when initial concentration was increased but increased when adsorbent weight was increased. Removal of Methylene blue by Ageratum conyzoide leaf powder was rapid and significantly above 80% in all initial concentrations examined. At optimum conditions of pH 3, 20 minutes contact time and adsorbent weight of 60 mg for Methylene blue initial concentration of 20 mg/L, 40 mg/L and 60 mg/L, Methylene blue removal of 84.7%, 83.9% and 81.2% were obtained respectively. Results suggest that Ageratum conyzoide leaf powder could be poten...

Modelling of Adams-Bohart and Yoon-Nelson on the Removal of Oil from Water Using Microwave Incinerated Rice Husk Ash (MIRHA)

- This study investigated the possible use of Microwave Incinerated Rice Husk Ash (MIRHA) as adsorbent for the treatment of wastewater generated from oil and gas industry using the column adsorption method. Adams-Bohart and Yoon-Nelson models were used to analyze experimental data. MIRHA was found to be porous, have high surface area and consist of 87-97% silica. Results show that both Adams-Bohart and Yoon-Nelson models can be used to describe experimental data.

Preparation of Ti/IrO2 Anode with Low Iridium Content by Thermal Decomposition Process: Electrochemical removal of organic pollutants in water

Abstract In this study IrO2 (Iridium oxide) was coated onto a titanium plate anode from a dilute (50 mg/10 ml) IrCl3×H2O salt solution. Coating was done at high temperature (550∘C) using thermal decomposition. Surface morphology and characteristics of coated surface of Ti/IrO2 anode were examined by FESEM and XRD. The coated anode was applied for electrochemical removal of organic pollutants from synthetic water samples in 100 mL compartment of batch electrochemical cell. About 50% COD removal was obtained at anode prepared with low Ir content solution while 72% COD removal was obtained with anode prepared at high Ir content. Maximum COD removal was obtained at 10 mA/cm2 current density.

Polycyclic aromatic hydrocarbons removal from produced water by electrochemical process optimization

Abstract Produced water is actually the wastewater separated from petroleum crude oil. Electrochemical-oxidation experiments was conducted for degradation of 16 priority polycyclic aromatic hydrocarbons (PAHs) using DSA type Ti/IrO2 anode. Laboratory scale batch reactor was used for degradation studies. To get the maximum PAHs removal electrochemical process optimized on three independent variable current density, pH and electrolysis time. The response surface modelling (RSM) based on a Box-Behnken design was applied to get appropriate experimental design. X1, X2 and X3 are the coded factors of independent variables such as the current density, pH and electrolysis time, respectively. Maximum removal was 95.29% at optimized conditions such as current density of 9 mA/cm2, pH 3 and electrolysis time 3.7 h. Quadratic model was suggested best fit model. The results of the Analysis of Variances (ANOVA) for PAHs demonstrated that the model was highly significant.

Evaluation of Leachate Characteristics from Different Leachate Ponds in a Semi-Aerobic Landfill

In this study, the performance of a semi-aerobic landfill was monitored through the analysis of leachate composition collected from different leachate ponds; collection pump (CP), equalization pond (EQ) and aerated pond (AP). The landfill site is located in the tropical environment of the central region of Malaysia. Twenty parameters were analyzed and the average values of the parameters for leachate at the CP, EQ and AP, which include; pH (8.24, 8.00 and 8.73), total kjeldahl nitrogen (3987.25, 8744.6, 1927.31 TKN-N), ammonia-N (3726, 3800, 1560 mg/L NH3-N), nitrate (26.7, 33.3, 25 mg/L NO3-N), total phosphorus (0.85, 0.78, 0.92 mg/L PO43-), BOD5 (305, 311.3, 201 mg/L), COD (16100, 14587, 12780 mg/L), BOD5/COD (0.019, 0.021, 0.016), turbidity (405, 735, 940 NTU), colour (3991, 4122, 3412 Pt Co), TSS (109.3, 58, 50.7 mg/L), EC (32.8, 21.9, 37.0 mS/cm) and TDS (21.98, 14.7, 24.8 mg/L) were recorded appropriately. The results realized from the analysis of the three ponds, were compared with previously published data and also the standards specified by the Malaysia Environmental Quality Act 1974. The obtained results indicate that the leachate from the aerated pond could remove some of the pollutants and was more stabilized when compared with the leachate from the pump and equalization ponds. It is also found that the aeration process in aerated pond could enhance the reduction of pollutants in the leachate. The measured leachates would require appropriate treatment methods in order to reduce the pollutants to meet the discharge standard before releasing them into water courses.

Copper Removal with Biologcal Treatment Aided with Modified Adsorbents

The performance of a biological system was evaluated for copper removal with and without the addition of an adsorbent to the aeration compartment. Three different reactors were employed in this study. The first reactor consist of biomass alone and was used as a control reactor (CR). The second reactor consist of biomass and microwave incinerated rice husk ash (MIRHA) whereas the third reactor consist of biomass and hybrid adsorbent (HA), which is a mixture of MIRHA and groundwater treatment plant sludge (GWTPS). The reactors were operated at solid retention time (SRT) of 30 days and hydraulic retention time (HRT) of 19.8 hours. The experiment was conducted in 8 different phases consisting of various copper concentrations coming from the influent source. The first and second phase were acclimation period during which copper was not added to the influent wastewater. From the third to the eight phase, copper was fed to the reactors at different concentrations. Reactor performance was monitored every two days. Results show that copper toxicity was significant for the control reactor from phase from phase 5 to phase 8 with effluent concentration between 0.34 – 2.62 mg/L. Copper removal was significant for both MIRHA and HA reactor. Effluent copper concentration in the MIRHA reactor was 2.04 mg/L and 1.09 mg/L for HA reactor at phase 8 (copper concentration 15 mg/L). Addition of the adsorbents (MIRHA and HA) enhanced the biomass tolerance towards copper toxicity at high concentration and improved copper removal efficiency. This study, therefore demonstrates that low cost non-conventional adsorbents could be utilized as support materials to enhance biomass tolerance towards heavy metal toxicity.

Determination of optimum range for hexavalent chromium Cr(VI) removal using ageratum conyzoide leaf powder (ACLP)

The optimum range of process parameters for hexavalent chromium Cr(VI) removal were determined in a batch study using Ageratum conyzoide leaf powder (ACLP) as adsorbent. The process parameters were varied in the range 2-10 for Initial solution pH, 135-400 mg/L for initial concentration, 30-180 minutes for contact time and 0.1-0.6 g for adsorbent weight. Solution pH was adjusted using 0.1 M H2S04 and NaOH respectively. Results show that initial solution pH was vital for Cr(VI) removal. At low initial solution pH (pH 2), Cr(VI) removal was high but decreased when the solution was increased from pH 4 to 10. Cr(VI) removal decreased when initial solution concentration was increased and increased when contact time and adsorbent weight was increased. At initial solution concentration of 135 mg/L, residual Cr (VI) concentration was about 53.7 mg/L (61 % removal efficiency) at optimum range of pH 2, adsorbent weight 0.3 g and contact time 120 minutes. Ageratum conyzoide leaf powder (ACLP) could be a potential ads...

Removal of Oil from Water by Column Adsorption Method Using Microwave Incinerated Rice Husk Ash (MIRHA)

This paper addressed the potential use of microwave incinerated rice husk ash (MIRHA) as an adsorbent for the treatment of oily wastewater generated from an oil and gas industry. Presence of total petroleum hydrocarbon (TPH) in oil and gas wastewaters hinders the potential reuse of such wastewaters. The adsorbent MIRHA was produced by burning rice husk at two temperatures of 500 and 800 °C, designated as MIRHA500 and MIRHA800, respectively. The adsorbent was found to be highly porous, light weight with a very high external surface area and consist of 87–97 % silica. Adsorption of oil onto MIRHA500 and MIRHA800 was investigated in this study. Effect of contact time, adsorbent dose and concentration of MIRHA on adsorption process was determined by means of column adsorption study. X-Ray diffraction (XRD) and scanning electron microscopy (SEM) were used to determine the physical properties of MIRHA. MIRHA800 was found to be more effective with a removal ratio of 0.94 as compared with MIRHA500 (0.74) and higher throughput volume to exhaustion and breakthrough at increasing bed depth due to its larger surface area. Theoretically, contact time, adsorbent dose and concentration of MIRHA affect the adsorption process.

Volatile Fatty Acids Production through Degradation of Biomass by Anaerobic Digestion (Mesophilic and Thermophilic)

Volatile fatty acids (VFAs) are fatty acids with a carbon chain of six carbons or fewer and usually referred to as short-chain fatty acids (SCFA). Degradation of biomass through anaerobic digestion will produce volatile fatty acid (VFAs) through anaerobic digestion process. The volatile fatty acids obtained can be recovered and used to produce methyl or ethyl esters which, could be advantageously used as additive for biodiesel [1]. Anaerobic digestion is a biological process that can degrade waste organic material by concerted action of a wide range of microorganisms in the absence of oxygen. The objective of this study is to degrade the biomass through anaerobic digestion for the production of volatile fatty acids by two different temperatures condition which are mesophilic and thermophilic; 35°C and 55°C respectively. The production of volatile fatty acids was optimized by varying the cycle period of the digestion process with the concentration of Mixed Liquor Suspended Solid (MLSS) maintained at 8000 mg/L for each cycle. The degradation of biomass was carried out using anaerobic sludge digester which 2L of biomass was digested from day 1 until day 24 (cycle period). The tests of MLSS and Mixed Liquor Volatile Suspended Solid (MLVSS) was conducted by Standard Method 2540-D while test for VFAs was conducted through Standard Method 8196. The highest production of volatile fatty acids was obtained in day 5 of cycle period where the concentration is 441 mg/L as acetic acid (HOAC).