History and Objectives: Exited sewage following mechanical methods contains pathogenic agents. Therefore, swage clearance with chlorine and other compounds is necessary. It has been reported that in fixation ponds with regard to a long-time standing, there is a high rate of clearance and there is no need of additional clearance and this reduces the costs. Therefore, this study was carried out to determine the clearance rate of fecal Coliforms in fixation ponds of Shoosh sewage refinery in Tehran in 1999. Materials and Methods: The semi-experimental strategy of this study was carried out on integrated stabilization pond in all of the seasons using two feeding sewage methods The system is a combination of anaerobic and facultative ponds and then two high-performance and complementary with a total time of 20 days. Sampling was done every two weeks from inlet and outlet sewage and number of fecal Coliforms was counted and data were analyzed statistically. Results: It was found out that clearance rate of fecal Coliforms was greater in spring than other seasons (99.97%) and was rather great in winter (greater than 99.5%). This indicates the high performance of the system for clearance of pathogenic agents from sewage. Conclusion and Recommendations: It is concluded that combinational tixation ponds have an appropriate performance for clearance of pathogenic agents. Feeding through upward current can increase the performance, as does the facultative pond. It is recommended to carry out more studies in this field.    

Emerging economies have often poor hygiene practices in traditional milk and dairy production all over the world. Therefore, pathogenic bacteria in milk pose major public health concerns especially for those communities who still consume raw milk. Escherichia coli and Coliforms are often used as indicator microorganisms, so their presence in food implies poor hygiene and sanitary practices. The main purpose of this article is to review information on milk quality and coliform bacteria contamination associated with the production and distribution of raw milk in some of the low and middle income economies around the world. Data reported on coliform counts in milk samples from some countries categorized as low and middle income economies in Africa, South America, Asia, and Europe. Local marketing of raw milk has been increased in the low and middle income countries because of low purchasing power of most native consumers. This population is at risk of illnesses from food-borne pathogens as a result of poor milk handling along the informal milk value chains. The regulatory bodies from these low and middle income countries are usually underfunded; therefore the safety standards of the milk chain cannot be sufficiently provided, endangering public health. On the other hand, there are huge losses of milk due to microbial spoilage in the low and middle income countries. So, it is necessary for the low and middle income countries to invest in infrastructures and establishments such as potable water supply to the dairy actors, increase the electricity connectivity from national grid and off-grid, improve the transport infrastructure, and financial support of the standards regulatory institutions. Paying attention to the mentioned actions can help to improve milk safety and quality and thereby reduce the risk of the food-borne illnesses.

Background: One of the most challenging and critical processes in wastewater treatment is sludge treatment. This study aimed to investigate the effects of low frequency ultrasound and high level of energy on inactivation rate of total coliform of sludge and ascertain the optimal operating parameters of the ultrasound waves.Methods: In this research, the density of ultrasound (W/mL) and time (minutes) were investigated. The effect of these parameters on the inactivation of total coliform in sludge was also investigated.Results: The results revealed that the optimum operating time and ultrasound density were 30 minutes and 2.5 W/mL, respectively. Also, the frequency of 20 kHz of total coliform removal rate in these conditions was 99.44% .Conclusion: Ultrasound waves as well as micro and nano bubbles could remove total coliform and decontaminate the sludge, thereby incrementing the rate of treatment.

The continuous filter is a kind of sand filter, which will operate without any interruptions for backwashing and also it accepts high-suspended solid levels in feed stream. Fouled sand is continuously removed from the filter bed, washed and recycled back without interruption with filtration process. Various samples of water with certain amounts of turbidity enter through a feed pipe and being distributed to the filter. A central column runs from top to bottom of the filter. The water is led through an outer tube in the column by a set of radial, distributor arms. The polluted water flows up ward through the sand bed. The water emerges; clean, in the top section of the tank, and eventually spills over a weir, and then inters into a discharge pipe. In this research, the continuous sand filter was studied to determine its disinfection efficiency in addition to turbidity removal. The results showed that the filtered water had a high quality and the turbidity reduction was 95.5 %. Inspecting the work of the filter had revealed that the removal rates of Coliforms and microbial colonies were 99.67 % and 98.99 % respectively. On the other hand, by the use of direct filtration, turbidity reduction was over 97 %. In direct filtration, drinking water with less than 1 NTU turbidity was provided. This continuous sand filter has the advantage of stable operation and more energy saving as compared to the conventional ones.

Coliform group has been extensively used as an indicator of drinking water quality and historically led to the public health protection concept. Multiple tube fermentation technique has been currently used for assessment of the microbial quality of drinking water. This method, however, has limitations. Enzymatic assay constitute an alternative approach for detecting indicator bacteria, namely total Coliforms and E.coli in various aquatic environments. This study compared the performance of LMX® broth as an enzymatic assay with the standard methods multiple tube fermentation technique and presence–absence test, for the detection of indicator Coliforms in drinking water samples. In addition, the potential effect of water quality on the microbial detection method was assayed through measurement of some physicochemical parameters. From the 50 drinking water samples tested, 8 (16%) and 7 (14%) contained total Coliforms and E.coli as indicated by all three techniques. Although on average the LMX recovered more total Coliforms and E.Coli numbers comparing to multiple tube fermentation, but there was no significant difference. A significant difference existed between the level of residual chlorine for positive and negative samples. In conclusion, enzymatic assay showed a rapid and less labor method, allowing the simultaneous detection of total Coliforms and E.coli. The method is particularly useful in the early warning of fecal pollution of drinking water.

Introduction: The water which is prepared for specific uses and has lost its quality is called wastewater. Wastewater of hospitals and health centers contains different pathogens that reveals the necessity of attention to this pollution sources. Therefore, this study was designed to evaluate the antibiotic resistance pattern of bacteria isolated from hospital wastewater treatment plant.Methods: In this descriptive study (in 2015), the samples of wastewater were collected from the hospital aeration ponds in different seasons. Samples were transferred to the laboratory under standard conditions. The bacteria count were performed by multiple tube test and were reported according to MPN (Most Probable Number) method. Microbial identification tests were performed according to conventional methods. The investigation of antibiotic resistance was performed using Kirby– Bauer standard technique according to method of Clinical and Laboratory Standard Institute 2014 (CLSI). Data were analyzed by SPSS software.Results: In this study, a total of 20 samples were collected in different seasons. Despite more cases of isolated Coliforms, the count of enterococci was higher than that of the Coliforms. The highest resistance to ceftazidim (100%) and trimethoprim (85%) was observed in Enterococcus and Coliforms, respectively.The highestsusceptibility to meropenem, imipenem, gentamycin, and ceftazidim (100%) was observed in Pseudomonas. Also, in the spring and autumn, the antibiotic resistance was higher than in the other seasons.Conclusion: It is necessary to pay attention to the sources of contamination in order to prevent increasing the burden of contamination of highly resistant bacteria. In addition, it is necessary to conduct a national survey to determine phenotypic and genotypic resistance patterns of bacteria in Iran.

Background and Objective: Hospitals, as one of the most important social places, play a basic role in providing, conserving and improving of the individual and community health. Hospital wastewater contain different pathogenic microorganisms, hazardous chemicals, radioactive substances, and organic and inorganic materials. In this research, removal of coliform bacteria from hospital wastewater by electrocoagulation technology has been evaluated. Methods: Wastewater samples were collected from Yahianejad hospital wastewater treatment plant belong to Babol Universty of Medical Sciences as a grab sampling before the chlorination unit. Electrocoagulation experiments were carried out in the electrical voltage (10, 20, 30V), contact time (30, 60, 90 minutes), and using two types of galvanized iron and aluminum electrodes. Before and after electrocoagulation starting, the samples were taken middle of the reactor and the experiments were conducted multi-tube fermentation method (15 tubes with dilution). Results: The results showed that the maximum removal of Coliforms in galvanized iron and aluminum is 99. 7% and 95. 8% respectively. As well as, with increasing the voltage and contact time, the removal rate of colifirms in the galvanized iron electrode increases. Totally, the galvanized iron electrode has better removal efficiency of Coliforms than aluminum electrode in contact time more than 60 min. Conclusion: The results of this study showed that the electrocoagulation process is an effective method for the removal of Coliforms from hospital wastewater at pilot scale and can be used as complementary disinfection method.

Background and Objectives: Antibiotics are among the most effective drugs used to treat humans. These materials enter in different ways into sewage and known as important biological contaminants in aquatic and agricultural environment. The availability of conditions for antibiotic resistance gene transfer to sewage bacteria, converted human environmental wastes to an important source of antibiotic resistant bacteria. Considering the spread of antibiotic resistant strains in treatment centers of Qom province, the aim of this study is to investigate the frequency and antibiotic resistance pattern in coliform bacteria isolated from wastewater treatment system of Qom city in different seasons.Methods: This study was carried out on 120 samples of municipal wastewater treatment plant (incoming and outgoing) in Qom. After sampling, transport of samples to the laboratory, isolation and phenotypic identification of bacteria, and Determination of antibiotic resistance pattern, were performed according to CLSI standards. The frequency of bacteria was determined using most probable number (MPN) method.Results: In this study, of 384 strains of bacteria (isolated in spring, summer, and winter), Escherichia coli (50%), Citrobacter (30%), Enterobacter (11%), Klebsiella (1%) and non-coliform bacteria (Proteus sp.) 8%, were identified. The most antibiotic resistance was observed in Citrobacter and Enterobacter bacteria (isolated in summer) to penicillin G with a frequency of 94%.Conclusion: Due to the high frequency of antibiotic resistance in Citrobacter and Enterobacter strains in the sewage treatment plant in Qom province, especially in the summer, this ecosystem can be reported as an important source of spread of antibiotic-resistant strains.

Purpose In waters and wastes, direct pathogen detection is difficult and time consuming. Therefore, Coliforms are used as indicators to measure the presence of pathogens. Composts originated from extrements, sewage sludges and plant wastes those contact with manures may have potential health hazard to human. Therefore, the detection of Coliforms both during composting and in the obtained composts is used to investigate the presence of pathogens for determination of the potential health risk.Methods In this study, the effect of six different aeration rates on elimination of total and faecal coliform bacteria was investigated during in-vessel aerobic composting of vegetable–fruit wastes. Total coliform and faecal coliform numbers in the samples were measured by the most probable number method.Results Coliforms significantly increased before the thermophilic stage except the faecal Coliforms in the reactor which operated with the lowest aeration. The Coliforms suddenly decreased after thermophilic stage in all reactors. Total Coliforms reduced within the range of 78.2–99.9 % while faecal Coliforms reduced within the range of 72.5–99.9 % after the thermophilic stage. At the end of the composting period (day 18), total Coliforms and faecal Coliforms reduced within the range of 99.9–100 %.Conclusions Although all the aeration rates used in the present study were effective for the elimination of Coliforms, the lowest faecal coliform number was seen in the reactor that had the lowest aeration rate. At the end of the study, the faecal coliform numbers in all reactors confirmed some limits for the application activities of composts.