The effect of a Sewage Treatment Plant modernization on changes in the microbiological and physicochemical quality of water in the receiver (original) (raw)
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Microbiological and Epizootological Characterization of Materials from Wastewater Treatment Plant
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Journal of Environmental Science and Technology, 2012
The marine environment plays a major socioeconomic role in the Agadir region (south-west Morocco). This area, which hosts important fishery resources, is currently not spared from the pollutants produced in the course of agricultural, domestic, industrial and tourist development. The aim of this study is to assess the impact of the Taghazout bay tourist resort on the bacteriological and physicochemical quality of the coastal waters of Taghazout. The seawater samples were collected between March 2016 and March 2018 at three sampling sites (S1, S2 and S3) in order to monitor the concentrations of fecal coliforms (FC), fecal streptococci (FS) and total germs (TG). The results of physicochemical parameters show seasonal fluctuations influenced by climatic factors. The spatio-temporal monitoring of the bacteriological parameters shows that the average total germ count is 127.05 CFU/100 ml, 39.61 CFU/100 ml for fecal coliforms and 15.21 CFU/100 ml for fecal streptococci. The values of FC80, FC95 and FS90 do not exceed the guide values of the Moroccan standards. This classifies the Taghazout beach in category A (good quality of bathing water). The monitoring analysis recorded by the Pearson correlation test between the environmental parameters and the level of fecal bacteria showed that there was a significant positive correlation between the FC concentrations and rainfall; the FS concentrations showed significant positive correlations with all the environmental parameters while the TG concentrations indicate no correlation with them. The fecal contamination parameters should be routinely monitored for improving the environmental conditions of coastal cities. This must be the case for the Taghazout coastline where a regular monitoring program must be established to evaluate the impact of the new tourist resort "Taghazout bay" on the environmental quality of this ecosystem.
Water Science and Technology, 2012
This study involved collaboration between three centres with expertise in viruses, bacteria and protozoa. The focus of the research was the study of the dissemination and removal of pathogens and faecal indicators in two sewage treatment plants (STP1 and STP2) using tertiary treatments. Samples were collected over a period of five months through the sewage treatment processes. Analysis of the samples revealed that the plants were not efficient at removing the faecal indicators and pathogens tested during the study. From entry point (raw sewage) to effluent level (tertiary treatment effluent water), the experimental results showed that the reduction ratios of human adenoviruses were 1.2 log10 in STP1 and 1.9 log10 in STP2. Whereas for Giardia spp. and Cryptosporidium spp. the reduction ratios were 2.3 log10 for both pathogens in STP1, and 3.0 and 1.7 log10 in STP2, respectively. Furthermore, the presence of faecal indicators and pathogens at different sampling points was evaluated re...
International Journal of Hygiene and Environmental Health, 2008
Six sewage treatment plants (STP) were investigated over a 12-month period in order to measure the microbiological load of untreated municipal wastewater and to evaluate the removal efficiencies of different treatment systems. The STP investigated can be classified into three categories: bigger plants with tertiary treatment, smaller plants with enhanced secondary treatment, and very small compact facilities. The plants studied had a considerable quantitative impact on the hydrology of the catchment area; consequently, it was anticipated that the microbiological load of the effluent would also be significant. Eighty samples were taken from the influent and effluent of the STP, regardless of weather conditions, and several bacterial and two parasitological parameters were analysed. The average microbiological reduction of each STP was dependent on its capacity and treatment procedures and varied between 1.9 and 3.5 log 10 . Small compact facilities had a significantly lower removal efficiency (2.071 log 10 ) and discharged treated wastewater with a poorer microbiological quality compared to larger plants with tertiary treatment or with enhanced secondary treatment (X2.8 log 10 ). Final sand filtration and extensive intermediate settling considerably improved the overall microbiological removal efficiency. During the study period, the microbiological water quality of the receiving water course was not significantly impaired by the discharge of any of the investigated plants; however, the compact facilities showed critical treatment deficiencies. In particular, the reduction of Giardia cysts was insufficient (o1.5 log 10 ) compared to that of the bigger plants (43.0 log 10 ). In order to quantify the overall impact of microbiological loads on the receiving watercourse in this catchment area, it is also necessary to assess the pollution from combined sewer overflow basins and diffuse pollution. This will be considered in subsequent studies.
Evaluation of microbiological and physicochemical indicators for wastewater treatment
Environmental Toxicology, 2004
Background: Access to clean and safe drinking water is still a problem in developing countries and more pronounced in rural areas. Due to erratic supply of potable, rural dwellers often seek for an alternative source of water to meet their basic water needs. The objective of this study is to monitor the microbiological and physicochemical water quality parameters of Nzhelele River which is a major alternative source of drinking water to villages along its course in Limpopo province of South Africa. Methods: Membrane filtration method was employed in evaluating the levels of E. coli and Enterococci in the river water from January-June, 2014. Specialized multimeter was used to measure the pH, electrical conductivity and turbidity of the river water. Ion Chromatograph was used to measure major anions such as fluoride, chloride, nitrate and sulphate in the water. Results: High levels of E. coli (1 x 10 2-8 x 10 4 cfu/100 mL) and enterococci (1 x 10 2-5.7 x 10 3 cfu/100 mL) were found in the river water and exceeded their permissible limits of 0 cfu/100 mL for drinking water. Turbidity values ranged from 1.12-739.9 NTU. The pH, electrical conductivity, chloride, fluoride, nitrate and sulphate levels were below their permissible limits for drinking water. Conclusion: The river water is contaminated with faecal organisms and is unfit for drinking purposes. However, the levels of the major anions accessed were within the permissible limits of drinking water.
Changes in the Microbial Composition of Municipal Wastewater Treated in Biological Processes
Journal of Ecological Engineering, 2016
Municipal wastewater is characterized by diverse microbial content, largely dependent on their sources as well as many other factors like condition and health of their producer, but also environmental factors. The number and share of individual bacterial population in wastewater is changing during the process of their treatment in wastewater treatment plants. The microbial content of treated wastewater is significantly affected by the type of technology used for wastewater treatment. The paper presents the results of the species composition of bacteria present in the wastewater at various stages of treatment for the two different technologies. Samples of wastewater from hydroponic wastewater treatment plant and from the plant whose technology is based on biofilters were analysed. A key mechanism for wastewater treatment in both cases is biological treatment, using microbial activity that decomposes pollutants in the wastewater, which significantly contributes to changes in the species composition of bacteria comparing to microbiological composition of sewage flowing into the treatment plant. Analyses of microbial composition showed that in the objects consisting of preliminary tank and biofilter, composition of bacteria species is changing, but many species isolated from raw sewage is also found in treated wastewater. In the plant with hydroponic lagoon after wastewater treatment throughout the process system, bacteria present in raw sewage or in wastewater after biological treatment were not identified in the outlet.
Bacteriological, Physical And Chemical Properties Of The Pagla Sewage Treatment Plant’s Water
Dhaka University Journal of Biological Sciences, 2012
Samples from Pagla sewage treatment plant at different treatment stages showed more or less similar temperature (26.9 -27.5 0 C). The pH ranged from 7.2 -7.9. Influent water and primary sedimentation tank water were brownish in colour while sludge water was light black. The lagoon water and treated water were greenish. The ammonium-nitrogen (NH + 4-N) and nitrate-nitrogen (NO -3-N) ranged from 5.24 -61.94 mg/l and 2.55 -11.02 mg/l, respectively. Phosphorus of the water was 1.34 -4.50 mg/l. The suspended solids (SS) ranged from 25.48 -374.69 mg/l. In the present study the amount of SS in the treated water were found to be quite satisfactory. The total bacterial population in Pagla sewage treatments plant was in between 2.9 × 10 4 and 2.5 × 10 6 cfu/ml. The qualitative bacterial spectrum showed a potential consortium of bacteria associated with the treatment plant. Both Gram positive and Gram negative bacteria were present. Gram positive bacteria were represented by the different species of the genus Bacillus, Aureobacterium and Kurthia. Among them Bacillus was the dominant genus. The different species of Bacillus were Bacillus sphaericus, B. fastidiosus, B. circulans and B. pasteurii. Gram negative bacteria were Zoogloea, Yersinia, Citrobacter and Pseudomonas. A good number of microorganisms were found to be associated with the bio-oxidation of the organic compounds of the influent. The Zoogloea along with other free flowing aerobic heterotrophic bacteria like Bacillus, Pseudomonas could play the major role in the sewage treatment.
Determination of overall microbial activity in sewage treatment plants using FDA hydrolysis assay
DESALINATION AND WATER TREATMENT, 2017
In the present study, the fluorescein diacetate (FDA) activities using hydrolysis assay as well as removal efficiencies in terms of physico-chemical and biological parameters has been investigated for some of the sewage treatment plants in Mumbai, India. Effect of various process parameters such as pH, temperature and time on FDA hydrolysis of aerated lagoon treated samples has been studied. The pH, temperature and time which executed maximum FDA hydrolysis were 7.8, 50°C and 1.25 h, respectively. For Bhandup sewage treatment plant (STP), the FDA activity of 0.01 µmole/mL/h in raw sewage was further increased to 0.11 µmole/mL/h and 0.10 µmole/mL/h during the treatment for lagoon 1 and 2 respectively. The FDA activity after aerated de-gritting chamber was found to be 0.07 µmole/mL/h which was enhanced to 0.10 µmole/mL/h and 0.08 µmole/mL/h for lagoon 1 and lagoon 2, respectively, in Versova STP. The enhanced microbial activities in aerated lagoons have clearly indicated the extent and efficiency of biodegradation-which was evidenced by the enhanced FDA activity. Therefore, in order to sense the pulse of any biological operation in a given sewage treatment plant, FDA hydrolysis assay can be used as a quick technique to assess the change in overall microbial activity.
Microbiological parameters as an additional tool to improve wastewater treatment plant monitoring
Ecological …, 2011
The operation of an activated sludge wastewater treatment plant (WWTP) was assessed by determining the removal efficiency of treatment processes. For that purpose, different physicochemical and microbiological parameters, including total, active and culturable bacteria, were measured along a year. Values of both physicochemical and microbiological parameters were significantly reduced by biological treatment but no relation between these groups of parameters was obtained. Besides, results suggest that microbiological parameters were more sensitive than physicochemical ones to changes in WWTP conditions (i.e. influent quality). Additionally, high percentages of noncultured (>88%) and noncultured remaining active (until 50%) cells were detected before and after treatment. Therefore, ISO standards adopted to enumerate indicator bacteria by Spanish legislation, and based on culturability, underestimate the bacterial population present in wastewater. We have compared two culture-independent methods for bacterial enumeration, microscopy and flow cytometry (FCM) and results indicate that FCM provides a rapid and automated quantification in WWTP. We conclude that microbiological parameters are essential to monitor the correct WWTP operation and we propose quantification of active bacteria as indicator of wastewater microbiological quality.