Papers by Author: F.A. Aisien

Abstract: The feasibility of treating brewery effluent using bio-catalysts (enzymes) was investigated. Carbohydrase, lipase, protease and a mixture enzyme made of carbohydrate and lipase were used. Brewery wastewater samples were collected and analyzed for 96 hrs, at intervals of 12 hrs. The physiochemical properties: biological oxygen demand BOD, chemical oxygen demand COD, total suspended solid (TSS), total dissolved solid TDS, pH, phosphorus (PO4), ammonium nitrogen (NH4-N), total hydrocarbon (THC) were determined using APHA standard method of analysis. The concentrations of the physiochemical properties of the brewery effluent decreased with increasing biodegradation time, for the various enzymes used. However, the different enzymes gave different percentage reductions of each of the physiochemical properties. The order of percentage reduction for the enzyme systems is mixed enzyme > carbohydrase > lipase > protease > control. Hence, the mixed enzyme gave the best results of 90%, 90%, 50%, 100%, 91.6% and 100% reductions for COD, BOD, TSS, NH4-N, PO4 and THC, respectively after 96 hrs. of biotreatment. However, the control gave the least percentage reductions of 6.9%, 5.3%, 16.4%, 7.1%, 5.8% and 50.0% for COD, BOD5, TSS, PO4, NH4-N, and THC respectively.

Abstract: Batch treatment of palm oil mill effluent (POME) was investigated using physical, chemical and biological methods. Physiochemical parameters such as pH, sulphate (SO42-), total dissolved solids (TDS), total suspended solid (TSS), chloride ion (Cl-), biological oxygen demand (BOD), chemical oxygen (COD) and metals (Fe2+, Zn2+, Ca2+ and Mg2+) concentrations were determined using American Public Health Association (APHA) methods. The results revealed that significant treatment was achieved at each stage. However, the biological method proved to be the best with percentage reductions of 45.6%, 97.6%, 71,0%, 50.1%, 80.4%, 93.8%, 72.0%, 85.4%, 93.2%, 77.7%, 86.2% and 85.7% for pH, SO42-, TS, TDS, TSS, Cl-, BOD, COD, Fe2+, Zn2+, Ca2+ and Mg2+ respectively. The concentrations after treatment were in conformity with the minimum acceptable standard of FEPA and WHO.

Abstract: This paper considered the toxicity assessment of some crude oil contaminated soils in Niger Delta areas. The soil samples were collected from different horizontal distances, vertical depths and contaminated soil of different ages. The heavy metals in the contaminated soils were digested and extracted using di-acid digested and DTPA extraction methods respectively. The physiochemical parameters (moisture content, pH, N, P and heavy metals (Ni, Pb and Cd) were analysed with APHA method. The heavy metals concentration was determined using atomic absorption spectrophotometer (AAS). The results show that the metals concentration decreased with the age of the contaminated soil and with increased vertical depths. However, the metals concentrations were almost constant at different horizontal distances. Similar trend was observed for the moisture content, pH, N, P and K.

Abstract: The effect of linear alkyl benzene sulfonate (LAS) detergent on the activity of cassava fermenting enzymes was investigated for 72 hrs. Enzymatic assay methods were used to determine the activity of cassava fermenting enzymes: cellulase, α-amylase, pectin methyl esterase and phosphorylase. The cassava fermenting media were made up of LAS detergent concentration of between 1g/L to 5g/L. The results show that the LAS detergent of 2g/L and 3g/L gave optimum enzyme activity. The order of enzyme activity was pectin methyl esterase > α-amylase > phosphorylase > cellulase.

Abstract: The search for alternative sources of energy from organic waste has been on in Nigeria. This report focuses on a simple design, fabrication and performance test of a prototype biogas digester. The volume of the digester was 340dm3 and that of the absorber/adsorber was 12.5dm3. The digester was fabricated using mild and stainless steels, styrofoam, polythene sheets and other materials. The digester can be moved about and agitated manually. In the performance test, 8.134L of biogas was generated within 14 days of anaerobic digestion of palm oil mill effluent (POME). The optimum pH and temperature for biogas production were 6.2 and 29oC respectively.

Abstract: The effects of detergent on the microbiological changes of cassava for fufu production were investigated for a period of 72hr. Microbiological analyses of the fermenting cassava samples using standard methods were carried out. Six microbial species: Lactobacillus plantarum, Citrobacter freundii, Corynebacterium manihot, Lactobacillus cellobioscus, Pseudomonas alcaligens, and Leuconostoc mesenteriods were identified for the control. The same organisms were identified for the low detergent concentrations (1g/L, 2g/L) except Corynebacterium manihot, Leuconostoc mesenteriods, which were completely destroyed. High detergent concentrations (4g/L, 8g/L) inhibited the growth and subsequently killed all the organisms living very few Citrobacter freundii behind. At low detergent concentrations the cassava ferment within 48hr without objectionable odour. However, at high detergent concentrations there was no fermentation even after 72hr. The control samples fermented after 72hr with undesirable odour.