Dimensionality Reduction Analysis of the Integrated Solar and Hydraulic Jump Enhanced Waste Stabilization Pond Model Parameters

The study investigated the structure of the integrated solar and hydraulic jump enhanced waste stabilization pond (ISHJEWSP) variables. Also, to determine the cluster of the most important variables that account for the performance of the ISHJEWSP using principal component analysis (PCA). Three sets of experimental ponds were constructed with varying locations of point of initiation of hydraulic jump. Wastewater samples collected from the inlet and outlet for varying inlet velocities were examined for physicochemical and bacteriological characteristics for a period of nine months. The Pearson’s R-matrix and KMO statistic were used in evaluating the structure of the variables. Consequently, the variables of temperature, pH, algae concentration, solar radiation, and locations of the point of initiation of hydraulic jump were subjected to PCA. Two components had eigenvalues above the Jolliffe’s criterion and in combination explained 90.66% of the total variance. The inflexion of the scree plot justified the retained components. The analysis after rotation revealed that the parameters of pH, temperature, solar radiation, and algal concentration loaded highly to component 1. This underscores the precedence of ambient climatic conditions, alongside the state of the wastewater in general, to the inlet velocity and location of point of initiation of hydraulic jump.

Modelling solar enhanced waste stabilization pond

Solar enhanced waste stabilization pond (SEWSP) was modeled in this research. In the analysis, SEWSPs of varying sizes, made of metallic tanks with inlet and outlet valves and solar reflectors, were constructed to increase the incident solar intensity. Wastewater samples collected from the inlet and outlet of the SEWSPs were examined for physico-chemical and biological characteristics for a period of twelve (12) months. The parameters examined were temperature, pH, detention time, total suspended solids, dissolved oxygen, biochemical oxygen demand (BOD5), chemical oxygen demand (COD), algae count, faecal coliforms and E. coli. The efficiencies of the SEWSPs with respect to these parameters fluctuated with depth, location of reflectors and variation in width. The SEWSP with a width of 0.2 m whose reflector was installed at the outlet position gave the highest treatment efficiency. The conventional model was modified to account for solar irradiation. The faecal bacteria removal was significantly higher in the enhanced pond than in the conventional pond at 0.10 level of significance. The verification of the conventional model gave a good correlation of r = 0.882 between the measured and calculated Ne/No with a low standard error of s = 0.010, while the irradiated pond gave a correlation and standard error of r = 0.959 and s = 0.012 respectively. The research revealed that with the incorporation of solar radiation in WSPs, a length/ width/depth ratio of 1:0.2:0.2 can be used in the design of SEWSPs for maximum treatment efficiency.

Acinetobacter baumannii detected on modified charcoal–cefoperazone–deoxycholate agar in a waste stabilization pond

Campylobacter is a recommended reference pathogen for the verification and validation of water recycling schemes in Australia and globally. In a larger study investigating the efficacy of pathogen removal in waste stabilization ponds (WSP), we cultivated bacteria from wastewater samples on modified charcoal–cefoperazone–deoxycholate agar (mCCDA) targeting the growth of Campylobacter. A high number of colonies characteristic of Campylobacter grew on this selective medium, but this did not correlate with qPCR data. Using primers targeting the 16S rRNA gene, and additional confirmatory tests to detect VS1, ompA, blaOXA-51-like, blaOXA-23-like genes, we tested 80 random colonies from 10 WSP samples. All 80 were identified as Acinetobacter baumannii. Wastewater grab samples taken three times over 6 months throughout the WSP system showed removal of A. baumannii in the WSP at rates similar to that of Escherichia coli. Our study suggests that mCCDA agar is not a suitable medium for isolating Campylobacter from environmental samples and that A. baumannii can be used as an indicator for removal of pathogens in WSPs.