Suleyman A. Muyibi

Coagulation of low turbidity surface waters with Moringa oleifera seeds

The use of Moringa oleifera seed extracts both as primary coagulant coagulant aid and its conjunctive use with alum in treating low turbidity waters was studied. The laboratory based studies used the natural polyelectrolyte to treat waters with turbidities between 23 and 90 ntu, obtained from three surface water sources in Kano, Nigeria. On the average, 50% turbidity removal was achieved when Moringa oleifera was used as primary coagulant. In combination with alum, the rates at which floes were formed were the same or often faster than with alum alone. In this study, between 40 and 80% savings in alum was observed. When used as a coagulant aid, the optimum dose was found to be 10 mg/1 while that of alum was 20 mg/1. Finally, it was observed that the time Moringa oleifera is applied (after slow mixing), is critical in determining the efficiency of coagulation. The optimum time for this was found to be 50 seconds after slow mixing.

Improvement of production of citric acid from oil palm empty fruit bunches: optimization of media by statistical experimental designs.

A sequential optimization based on statistical design and one-factor-at-a-time (OFAT) method was employed to optimize the media constituents for the improvement of citric acid production from oil palm empty fruit bunches (EFB) through solid state bioconversion using Aspergillus niger IBO-103MNB. The results obtained from the Plackett-Burman design indicated that the co-substrate (sucrose), stimulator (methanol) and minerals (Zn, Cu, Mn and Mg) were found to be the major factors for further optimization. Based on the OFAT method, the selected medium constituents and inoculum concentration were optimized by the central composite design (CCD) under the response surface methodology (RSM). The statistical analysis showed that the optimum media containing 6.4% (w/w) of sucrose, 9% (v/w) of minerals and 15.5% (v/w) of inoculum gave the maximum production of citric acid (337.94 g/kg of dry EFB). The analysis showed that sucrose (p<0.0011) and mineral solution (p<0.0061) were more significant compared to inoculum concentration (p<0.0127) for the citric acid production.

Activated carbons derived from oil palm empty-fruit bunches: application to environmental problems.

Activated carbons derived from oil palm empty fruit bunches (EFB) were investigated to find the suitability of its application for removal of phenol in aqueous solution through adsorption process. Two types of activation namely; thermal activation at 300, 500 and 800 degrees C and physical activation at 150 degrees C (boiling treatment) were used for the production of the activated carbons. A control (untreated EFB) was used to compare the adsorption capacity of the activated carbons produced from these processes. The results indicated that the activated carbon derived at the temperature of 800 degrees C showed maximum absorption capacity in the aqueous solution of phenol. Batch adsorption studies showed an equilibrium time of 6 h for the activated carbon at 800 degrees C. It was observed that the adsorption capacity was higher at lower values of pH (2-3) and higher value of initial concentration of phenol (200-300 mg/L). The equilibrium data fitted better with the Freundlich adsorption isotherm compared to the Langmuir. Kinetic studies of phenol adsorption onto activated carbons were also studied to evaluate the adsorption rate. The estimated cost for production of activated carbon from EFB was shown in lower price (USD 0.50/kg of activated carbon) compared the activated carbon from other sources and processes.

Treatment of surface water with Moringa Oleifera seed extract and alum – a comparative study using a pilot scale water treatment plant

The present study involved the use of a pilot scale water treatment plant to treat turbid surface water from a stream using processed Moringa oleifera seed and alum as primary coagulants. At low initial turbidity of 21.5 to 49.3 NTU, residual turbidities of 2.7, 1.8 and 1.4 NTU were achieved after treatment using Moringa oleifera, alum, and alum with Moringa oleifera as coagulant‐aid, respectively. For medium turbidities varying from 51.8 to 114 NTU, lowest residual turbidities of 2.9, 1.2 and 1.4 were achieved after treatment using Moringa oleifera, alum, and alum with Moringa oleifera as coagulant‐aid, respectively. For high turbidity varying from 163 to 494 NTU, minimum residuals of 1.4, 1.9 and 0.9 NTU were achieved after treatment using Moringa oleifera, alum, and alum with Moringa oleifera as coagulant‐aid, respectively. The proposed mechanism for turbidity removal by Moringa oleifera seed in this study is a combination of partial‐charge neutralization and micro‐bridging or an electrostatic patch mechanism based on the results of zeta potential measurements.

Surface water clarification using M. oleifera seeds

Turbid surface water was treated using a pilot scale water treatment plant comprising coagulation, flocculation, sedimentation and rapid gravity filtration, using Moringa oleifera seeds/alum as coagulants. Turbidity removal of M. oleifera, alum, and the mixture of both M. oleifera/alum were compared, and results obtained were 7.2, 4.2 and 3.2 NTU, respectively. The turbidity achieved using M. oleifera/alum mixture and alum were less than the required standard of 5 NTU, while M. oleifera/alum mixture recorded the least turbidity value (3.2 NTU) with removal efficiency of 99%. The natural alkalinity of the water did not vary during the treatment processes. Therefore M. oleifera/alum mixture could be considered as a suitable alternative for partial replacement of alum as coagulant in surface water treatment, which is an added advantage since M. oleifera is a natural product with less or no side effects as compared to alum as a chemical agent.

In-Vitro Antibacterial Activity of Processed Moringa Oleifera Seed Extract: Kill-Time Study

Earlier research conducted on moringa oleifera seed extract not only reveals its excellent coagulant property; it also being proven to possesses antibacterial activity against microorganism. An antibacterial agent 4 (α-Lrhamnosyloxy) benzyl isothiocyanate, a plant synthesized derivatives of benzyl isothiocyanates has been identified as the active antibacterial agent present in the seed. In this study, the mode of antibacterial action was determined using the kill-time study on e.coil and pseudosomonas aeruginosa bacterial strains. The minimum inhibitory concentration (MIC) assay was done using macrodilution broth. MIC values were varied from 0.0125mg/ml to 0.1mg/ml. Kill-time assay was carried out based on standard procedure. The growth of the microbes was monitored for every 30 minutes by viability counting on agar plate. Log reduction of viable cells counts ranged from 0 to 3.6 log10 for e.coli and 1log10 to 4log10 for p.aeruginosa. The results of the kill-time study revealed that the extract was bactericidal against e.coli and p.aeruginosa within 30 minutes of contact resulting in about 90% elimination of the strains. Most of the microbes were killed at high MIC value of 0.1 mg/ml, which might suggest that the seed extract exhibits concentration-dependent killing.

Solid State Bioconversion of Oil Palm Empty Fruit Bunches for Production of Citric Acid by Wild Strains of Aspergillus Niger

This study investigated the potential of Aspergillus niger strains for the production of citric acid from oil palm empty fruit bunches (EFB) through solid state bioconversion (SSB). Twenty six wild strains of Aspergillus niger isolated from lemon, orange, and sewage treatment plant sludge were evaluated. Factors considered in the study were citric acid production, sugar consumption, and protein content as growth indicator. Two strains of Aspergillus niger (IBO-103MNB) and (IBO-114MNB) were found to have good potential with citric acid production of 128.43 ± 6.3 and 140.50 ± 1 g kg-1 of dry EFB with bioconversion time of 4 and 8 d, respectively. The productivity of citric acid by these strains was found to be 32 and 17.5 g kg–1d–1, respectively.

Development of biological process with pure bacterial cultures for effective bioconversion of sewage treatment plant sludge

Forty-six bacterial strains were isolated from nine different sources in four treatment plants namely Indah Water Konsortium (IWK) sewage treatment plant (STP), International Islamic University Malaysia (IIUM) wastewater treatment plant-1,-2 and -3 to evaluate the bioconversion process in terms of efficient biodegradation and bioseparation. The bacterial strains isolated were found to be 52.2% (24 isolates) and 47.8% (22 isolates) in the IWK and IIUM treatment plants, respectively. The results showed that higher microbial population (9–10 × 104 cfu/mL) was observed in the secondary clarifier of IWK treatment plant. Among the isolates, 23 isolates were gram-positive bacillus (GPB) and gram-positive cocci (GPC), 19 isolates were gram-negative bacillus (GNB) and gram-negative cocci (GNC), and the rest were undetermined. Gram-negative cocci (GNC) were not found in the isolates from IWK. A total of 15 bacterial strains were selected for effective and efficient sludge bioconversion. All the strains were tested against sludge (1% total suspended solids, TSS) to evaluate the biosolids production (TSS% content), chemical oxygen demand (COD) removal and filtration rate (filterability test). The strain S-1 (IWK1001) showed lower TSS content (0.8% TSS), maximum COD removal (84%) and increased filterability (1.1 min/10 mL of filtrate) of treated sludge followed by the strains S-11, S-14, S-2, S-15, S-13, S-7, S-8, S-4, S-3, S-6, S-12, S-16, S-17 and S-9. The pH values in the fermentation broth were affected by the bacterial cultures and recorded as well. Effective bioconversion was observed during the first three days of sludge treatment.

Biological treatment of sewage treatment plant sludge by pure bacterial culture with optimum process conditions in a stirred tank bioreactor

Biological treatment of sewage treatment plant (STP) sludge by potential pure bacterial culture (Bacillus sp.) with optimum process conditions for effective biodegradation and bioseparation was carried out in the laboratory. The effective and efficient bioconversion was evaluated with the treatment of pure bacterial culture and existing microbes (uninnoculated) in sludge. The optimum process conditions i.e., temperature, 40°C; pH, 6; inoculum, 5% (v/v); aeration, 1 vvm; agitation speed, 50 rpm obtained from the previous studies with chemical oxygen demand COD at 30 mgL− 1 were applied for the biological treatment of sludge. The results indicated that pure bacterial culture (Bacillus sp.) showed higher degradation and separation of treated sludge compared to treatment with the existing mixed microbes in a stirred tank bioreactor. The treated STP sludge by potential pure bacterial culture and existing microbes gave 30% and 11%; 91.2% and 59.1; 88.5% and 52.3%; 98.4% and 51.3%; 96.1% and 75.2%; 99.4% and 72.8% reduction of total suspended solids (TSS, biosolids), COD, soluble protein, turbidity, total dissolved solids (TDS) and specific resistance to filtration (SRF), respectively within 7 days of treatment. The pH was observed at 6.5 and 4 during the treatment of sludge by pure culture and existing microbes, respectively.

Optimization of water treatment parameters using processed Moringa oleifera as a natural coagulant for low turbidity water

Moringa oleifera is a natural coagulant which can be used for water treatment in tropical developing countries. This study presents the results of production of natural coagulant from processed Moringa oleifera with simple technique (oil extraction, salt extraction, and microfiltration with 0.2 μm). The optimization study on physical factors was carried out for coagulation-flocculation process. Low initial turbidity water samples (synthetic and river water) were used with turbidity less than 50 Nephelometric Turbidity Units (NTU). The response surface methodology (RSM) was used, and the analysis of variance (ANOVA) was performed to validate the developed regression model. The residual turbidity obtained was 4.514 NTU for synthetic water and 1.598 NTU for river water by applying the optimum conditions of 40 rpm (low speed), mixing time of 41 minutes, and Moringa oleifera dosage of 0.75 mg/L.