Short communication Removal of metal ions using dead-end filtration

Experimental results on a study on removal of metal ions using lecithin-enhanced dead-end filtration with 0.1 micron nylon membrane has been reported in this paper. The effects of metal-ion concentration on the pH, conductivity and zeta potential of lecithin dispersions were determined. The zeta potential of lecithin was determined to be -79 mV whilst the critical micelle concentration was 9 g·ℓ-1. Significantly, the study showed that lecithin has the ability to adsorb metal ions. This study gives an alternate technology for metal ion removal from aqueous solutions. Water SA Vol.31 (3) 2005: pp.413-41

Multiple regression prediction of biochemical oxygen demand of wastewater from cocoa processing

Biochemical Oxygen Demand (BOD5) is an important parameter for verifying the quality of discharged water fr-om wastewater treatment plants. The 5 day duration required in determining BOD5 levels causes delay in decision making for process control of wastewater treatment facility, which normally requires only several hours of reside-nce time. Therefore, a multiple regression model was developed to predict BOD5 levels in wastewater produced from cocoa processing. The concentrations of Total Suspended Solids (TSS), Chemical Oxygen Demand (COD), Oil and Grease (OG) in the wastewaters were determined quickly within ~ 2 hours, and the data was used to form-ulate a multiple regression equation to predict the levels of BOD5 and associated statistics within a very short time. Thirty (30) data sets of TSS, COD and OG wastewater parameters were used as independent variables to develop the regression equation with BOD5 as dependent variable. Additional twenty five (25) data set from the same cocoa processing wastewater were used to verify and calibrate the model, which showed very good agreeme-nt between the model prediction and measured BOD5 values. The multiple regression equation could be used to give quick estimate of the BOD5 levels of the wastewater from cocoa processing and thereby facilitate the waste-water treatment process for the factory.Keywords: Biological oxygen demand, Chemical oxygen demand, Total suspended solids, Wastewater, Cocoa Processin

Principal component analysis of groundwater quality data underlying Geochemical processes of Dahomeyan formation and Togo series in the Ho Municipality (Ghana)

The physico-chemical quality data of groundwater extracted from 36 boreholes in Ho Municipality indicated that 11 sources recorded pH values outside WHO guideline range, while 5 recorded turbidity levels above WHO guideline limits. Sodium levels ranged from 1.80 to 544 mg/L with a mean of 111 ± 132 mg/l; chloride level ranged from 2.98 to 898 mg/L with a mean of 124 ± 183 mg/L, and cation and anion dominance was in the ord-er Na+ > Mg2+ > Ca2+ > K+ and HCO3- > Cl- > SO42- respectively. The quality data was subjected to Principal Component Analysis, and two components (PC1 and PC2) were extracted. The PC1 represented nearly 88.17 % of the variance and had high absolute loadings for electrical conductivity, calcium, alkalinity and chloride, indi-cating interactions of minerals from the Dahomeyan formation and Togo series with the groundwater in the area. The PC2 accounted for 6.62 % of total variance, showing high loadings for colour, turbidity, HCO3 and total iron. The major geochemical processes taking place might be the presence and dissolution of carbonates and dolomites, evaporated minerals and chemical reactions involving reverse ion-exchange in the aquife

Assessment of quality of drinking water in Amasaman, Accra (Ghana)

The physico-chemical and microbial quality attributes of untreated water samples from hand dug wells and treated water delivered by tankers (mobile services) were assessed to determine the susceptibility of Amasaman community to water borne diseases. The physico-chemical parameters of all the water sources for domestic use were within the World Health Organization (WHO) drinking water guidelines and Ghana Standards (GS), with the exception of turbidity and colour which showed higher values for the well waters. With respect to the micro-bial quality, the waters from the hand-dug wells and tanker services showed presence of both total and faecal coliforms, at levels higher than WHO and GS values of zero counts per 100 mL for drinking water. The poor microbial quality (presence of coliform bacteria) of all the water samples suggested susceptibility and exposure of the community to waterborne diseases on continuously drinking the available water