An Investigation of Sewage Water Treatment Plant and Its Physico-Chemical Analysis

Eco-friendly bioremediation of pollutants from contaminated sewage wastewater using special reference bacterial strain of Bacillus cereus SDN1 and their genotoxicological assessment in Allium cepa

The present study aimed to assess the Bacillus cereus SDN1 native bacterium's ability to clean up contaminated or polluted water. The isolated bacterium was identified by its morphological and biochemical characteristics, which were then confirmed at the genus level. Furthermore, the isolated B. cereus (NCBI accession No: MW828583) was identified genomically by PCR amplifying 16 s rDNA using a universal primer. The phylogenetic analysis of the rDNA sequence was analyzed to determine the taxonomic and evolutionary profile of the isolate of the previously identified Bacillus sp. Besides, B. cereus and the bacterial consortium were treated using sewage wastewater. After 15 days of treatment, the following pollutants or chemicals were reduced: total hardness particles removal varied from 63.33 % to 67.55 %, calcium removal varied from 90 % to 93.33 %, and total nitrate decreased range from 37.77 % to 22.22 %, respectively. Electrical conductivity ranged from 1809 mS/cm to 2500 mS/cm, and pH values ranged from 6.5 to 8.95. The outcome of in-situ remediation results suggested that B. cereus has a noticeable remediation efficiency to the suspended particles. A root tip test was also used to investigate the genotoxicity of treated and untreated sewage-contaminated waters on onion (Allium cepa) root cells. The highest chromosomal aberrations and mitotic inhibition were found in roots exposed to contaminated sewage water, and their results displayed chromosome abnormalities, including disorganized, sticky chain, disturbed metaphase, chromosomal displacement in anaphase, abnormal telophase, spindle disturbances, and binucleate cells observed in A. cepa exposed to untreated contaminated water. The study can thus be applied as a biomarker to detect the genotoxic impacts of sewage water pollution on biota. Furthermore, based on an identified bacterial consortium, this work offers a low-cost and eco-favorable method for treating household effluents.

Ozone reactor combined with ultrafiltration membrane: A new tertiary wastewater treatment system for reuse purpose

In the present research, a new technology using the application of ozone (O_³) together with an ultrafiltration (UF) membrane was tested for the tertiary treatment of wastewater. The primary and secondary wastewater-treatment systems were a septic tank and anaerobic filter. The experiment was divided into two stages: the first including only the application of O₃ in the reactor, and the second, inclusion of the UF membrane. During the first stage of the study, where only the ozone was applied, a time of 40 min was chosen, with removal levels for chemical oxygen demand (COD), five-day biochemical oxygen demand (BOD₅), total organic carbon (TOC), turbidity and ammonium (NH₄⁺) of 39.5%, 45.4%, 32.4%, 44.85% and 68.4% being recorded. During stage 2, the UF membrane inside the reactor was activated after 40 min of ozonation. The values for the removal of COD, BOD₅, TOC, turbidity, NH₄⁺ and total phosphorus were 89.13%, 95.41%, 82%, 93.4%, 14.75% and 79.67%, respectively. The use of O₃ + UF removed 100% of total coliforms and viruses from the secondary wastewater. In accordance with North American and European guidelines, the water resulting from the treatment process is fit for reuse. The operating costs can vary between 0.859 € m^-3 and 2.440 € m^-3 depending on the cost per kWh in each country. The experiments were conducted under batch-mode conditions, further evaluations about the real scale operation would require a previous pilot stage that would develop more tools for operations specifications and their costs. The results recorded here show that the performance of this new reactor design is effective in the tertiary treatment of wastewater, and should be available for use in the near future.