Monitoring of wastewater within the sewage network of university

Abstract

Rapid increase in population and industrialization has not only improved the lifestyle but adversely affected the quality and availability of water leading to ample amount of wastewater generation. The major contribution towards wastewater production is from sewage. Regular monitoring and treatment of sewage water is necessary to conserve and enhance the quality of water. This is the first study carried out on monitoring of sewage water within the sewage system of university (National University of Science and Technology, NUST). A total of 16 samples from different manholes were collected for physicochemical, microbial, and heavy metals analysis and were compared with final effluent taken from integrated constructed wetland (ICWSs) to assess its removal efficiency. The mean concentrations of influent and effluent were compared with national environmental quality standards (NEQS) for municipal discharge and international agricultural reuse standards (IARS), respectively. Among all physicochemical parameters, the influent values for chemical oxygen demand (COD) exceeded the limit of NEQS for discharge into sewage treatment plant (STP) and inland water, whereas for total suspended solids (TSS) it exceeded for discharge into STP. However, the effluent concentrations for all the parameters were found within the permissible limit set by IARS. The removal efficiency for different parameters was found to be phosphate- phosphorus (PO4 3 -P) 52, COD 53, TSS 54, total dissolved solids (TDS) 35, and total kjeldahl nitrogen (TKN) 36 %. Colony morphology was carried out to determine the most dominant bacterial strains based on shape, texture, and color. Gram staining was done to confirm the presence of bacterial species. Most of the bacterial strains grown on EMB agar exhibited green metallic sheen color, rod shapes and shiny texture, whereas on SS agar the maximum percentage of strains exhibited- circular shape, yellowish pink color, and shiny texture. Heavy metal concentrations were compared with WHO guidelines among which, lead (Pb) and chromium (Cr) exceeded the limit. Interpolation results showed that zone-2 was the most contaminated in comparison to zone 1 and 3. Statistical analysis showed that correlation of physicochemical parameters and heavy metals was found significant (p < 0.05). ICWSs are the most efficient, environmentally friendly, and cost-effective treatment option for sewage water treatment.