Microbial and Physicochemical Qualities of Septic Tank Wastewater: An Evaluation.

Emmanuel Esosa Imarhiagbe,Hector Henry Oyem,Ifeanyi Mirian Oyem

doi:10.37284/eajhs.4.1.469

Emmanuel Esosa Imarhiagbe, Hector Henry Oyem + Show 1 more

Open Access

https://doi.org/10.37284/eajhs.4.1.469

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Abstract

The physicochemical and microbial qualities of septic tank effluent samples from households within the study area were evaluated. Three replicate samples from Locations A, B, and C representing Agbor, Benin City, and Sapele regions of Delta and Edo States, Nigeria were collected from both the inlet tank (raw sewage) and the outlet chamber (semi-treated sewage) for physicochemical and microbiological analyses using standard methods. Results of the physicochemical analyses showed that pH values ranged from 6.5 – 7.7 across locations and in both the raw and semi-treated samples. Electrical conductivity (EC), Total suspended solid (TSS) and BOD was significantly higher (p>0.05) in the raw sewage (RS) than in the semi-treated (SS), while DO was higher (p>0.05) in the SS in all three locations sampled. Microbial analysis shows that total heterotrophic bacteria (THB) was highest in the RS in two locations. Microbial isolates from wastewater samples included Staphylococcus aureus, Proteus mirabilis, Escherichia coli, Pseudomonas aeruginosa, and Aspergillus niger. DO was low at an average of 3.20 and 3.73 mg/L in both chambers of the septic tank. Average BOD5 of 59.4 and 42.8 mg/L and COD average of 206.8 and 153.2 mg/L were reported for the RS and SS chambers. 0.3 was the value of the ratio of BOD5/COD for the RS and SS in the study. This infers that biodegradation was slow and inefficient in the septic tank system, and that modification of the design is recommended to increase retention time in the RS chamber

Highlights

Sewage, which is liquid waste, is the wastewater of a community
Average BOD5 of 59.4 and 42.8 mg/L and Chemical Oxygen Demand (COD) average of 206.8 and 153.2 mg/L were reported for the raw sewage (RS) and semi-treated sewage (SS) chambers. 0.3 was the value of the ratio of BOD5/COD for the RS and SS in the study. This infers that biodegradation was slow and inefficient in the septic tank system, and that modification of the design is recommended to increase retention time in the RS chamber
The pH of the SS was higher in locations B (7.2 ± 0.2) and C (6.7 ± 0.2) than they were in the RS samples in the same location

Summary

Introduction

Sewage, which is liquid waste, is the wastewater of a community. It is a combination of water-borne wastes from homes, businesses, health institutions, and industries (Angeli et al, 2018). For reasons of public health and conservation, man has been forced to develop methods of wastewater storage and treatment which results in the mineralization of the organic components of wastewater prior to its discharge into the natural environment. This is usually achieved by an adequate public or community sewerage system. Individual household sewage disposal system often referred to as septic tank system is the most commonly used domestic wastewater disposal method in Nigeria (Fidelia, 2004)

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