Purpose The research was focused on evaluating phytotoxicity of sewage sludge from two selected wastewater treatment plants in Czech Republic. Methods Laboratory experiments were carried out with samples of sewage sludge, which were focused on the evaluation of their phytotoxicity by using the PhytotoxkitTM testing set. Specifically, the inhibitory/stimulating effect was established on the growth of roots from the seeds of white mustard (Sinapis alba L. ). The chosen proportions of sewage sludge were 10%, 30% and 50%. The test was conducted in three repetitions. Additionally, the research also included a comparison of the effect of compost addition to the sewage sludge and its potentially increased stimulating effect on the growth of roots from the seeds of white mustard (Sinapis alba L. ). Ratios of compost were 5%, 15%, 25% and 50%. The test was conducted in three repetitions. Results Stimulating effect on the growth of white mustard (Sinapis alba L. ) was demonstrated only in samples with the sludge proportion of 10%. The results also show that the addition of compost reduced phytotoxicity of sewage sludge in all three tested ratios (5%, 15%, 25% and 50%). Conclusion It was found out that the addition of compost resulted in the decreased phytotoxicity of all tested sewage sludge samples, and hence in their suppressed inhibitory effect.

The Ravanj sewage treatment plan is in south of Delijan located in Markazi province. Rananj is located in mounted area and stoned layer coursed a dangerous condition because of no water drainage. So, water and sewerage management company decided to solve this problem by evaluation of its treatment. Refining of waste water done by Hans bioshoft package is used. This package is a safe, trouble free and environmentally friendly, has on biological filtering of odors, and can be installed on the ground in different levels. After installation the Hans bioshaft system, BOD and COD for out flow samples were measured. The results shown that the BOD and COD out flow are higher than standard BOD and COD proposed environment standard. We proposed some of recommendation for solving this problem. At the end, the results shown that the BOD and COD out flow were gone to suitable range.

This study investigated the occurrence and removal of 12 antibiotics (ciprofloxacin, enrofloxacin, levofloxacin, norfloxacin, nalidixic acid, azithromycin, clarithromycin, roxithromycin, lincomycin, novobiocin, sulfamethoxazole, trimethoprim) at four sewage treatment plants (STPs): two STPs in Kyoto, Japan and two STPs in Beijing, China. The STPs differed in design and operation conditions, utilized a variety of secondary treatment processes. The antibiotics were frequently detected in influents and effluents, and ranged from ng/L up to lower mg/L. In influent, clarithromycin (1.1–1.6 mg/L) and levofloxacin (3.6–6.8 mg/L) were detected in the highest concentration in Japanese and Chinese STPs, respectively. The overall elimination of the antibiotics were differed between STPs and ranged from negative to>90%. These data demonstrate that there are detectable levels of antibiotics are discharging from STPs, and only some of these antibiotics are being removed in a significant proportion by STPs. It was also observed that biological nutrient removal based sewage treatment processes (anaerobic– anoxic–oxic: A2O; and anoxic–oxic: AO) have relatively higher antibiotics removal efficiencies than oxidation ditch (OD) processes.

With the development of industries and agriculture, the issue of water supply and the consequent challenge of sewage is becoming increasingly important. Water recycling and the use of treated sewage is the most desirable option for water supply. Considering the operating costs of modern sewage treatment plants, the economic aspect of the issue should be considered in order to provide treatment costs in addition to the desire of wastewater consumers. In Mashhad, before 2016, all existing sewage treatment plants were stabilized by the traditional method and their treatment costs were not significant. Therefore, most of the sewage received income was spent on developing the sewage collection network. But in 2016, with the opening of two modern treatment plants in Mashhad, with a capacity of 60, 000 and 65, 000 cubic meters per day, each of which can bring the quality of effluent to standards of discharge to surface water, the issue of sewage price and the total treatment price of each cubic meter of sewage become important. Also, by imposing penalties based on quality parameters, certain subscribers such as restaurants and hoteliers can be directed to pre-treatment before evacuation to the network. In this article, based on the extracted results during one year of operation of these two treatment plants, comparisons have been made in terms of construction costs, operation, consumables, personnel and finally the output of both treatment plants which should introduce the advantages and disadvantages of both methods in terms of ease of operation and economic efficiency and in the construction of treatment plants, the type of treatment method should be selected with more awareness.

The ability of low cost flocculating material, Plantago psyllium mucilage (Psy), for removal of suspended (SS) solid from sewage and tannery has been successfully investigated. Jar test method has been used for flocculation studies. The effects of polymer dose, pH and contact time on per cent removal of solid wastes are reported. Increase in solid wastes removal was observed with increasing polymer dose upto a certain level, beyond which further increase in dosage shows a decreasing trend in solid removal. The maximum solid removal (94.69 %) was seen only after 1 hour and the suitable pH range was acidic to neutral in case of sewage treatment whereas the time required for maximum solid removal (87.03 %) was1 hour and suitable pH range was neutral to alkaline in case of tannery effluent treatment. X-ray analysis of pure P.psyllium mucilage and flocs got after treatment shows the interaction between the suspended solid with the mucilage.

Purpose: The aim of this study was to compare higher-order aberrations between personalized treatment (PT) versus personalized treatment advanced (PTA) photorefractive keratectomy (PRK) for myopia and myopic astigmatism.Methods: In this clinical trial, 80 eyes of 40 patients who met inclusion criteria were enrolled. They underwent PRK using PT or PTA algorithm randomly. Higher-order aberrations were measured and compared between the study groups pre-operatively and at months 3 and 6 postoperatively.Results: The two study groups were comparable in terms of preoperative higher-order aberrations.Compared to the preoperative values, higher-order aberrations were significantly increased in the PT group (p<0.001), but decreased in the PTA group (p<0.001). Spherical aberration exhibited a significant increase postoperatively in the PT group (p<0.001) but remained unchanged in the PTA group (P=0.57).Conclusion: PRK using PT algorithm resulted in an increase higher-order aberrations. PTA algorithm provided better results in terms of postoperative higher-order aberrations and could treat pre-existing higher-order aberrations.

Aerobic biological treatment systems are very suitable for removing contaminants of organic matter in the sewage. Accordingly, the continuity of the inlet flow to the treatment plant, in design and exploitation of these processes, is necessary to consider. One of the differences between industrial and low population areas wastewater, such as military garrisons, and the Municipal sewage, is their volumetric fluctuations. These fluctuations may have a negative effect on the activated sludge process,thus the efficiency of using balancing pool in activated sludge systems has been analyzed in this research. Wastewater treatment process is based on biologically activated sludge method and extensive aeration. In this method, the raw wastewater is directed to the pumping station gravitationally. Results illustrated that, the inlet flow rate to the treatment plant, has high fluctuations from 0 to 40 (m3/hour) at different hours of the day due to the low population. Based on the samplings, it has been determined that the efficiency of activated sludge process in removing the parameters of BOD5, COD, TSS and ammonia during one week is averagely 61, 61, 68 and 24%, respectively. According to the sewage standards, this treated sewage is not suitable for injection into water wells or surface water or for reuse in agriculture. Whilst, using the balancing pond and controlling the inlet flow to the aeration pond at a rate of 12 cubic meters per hour, the removal efficiency of BOD5, COD, TSS and ammonia escalates averagely 90, 90, 89. 19 and 81. 59%, respectively during a week.

Background and objective: Enterococci are the second agent of UTI, the third agent of bacteremia and the second agent of hospital infections. In recent years, vancomycin has been considered as one of the most effective treatments for enterococcal infections. The rapid rise in the vancomycin-resistant entrococci (VRE) has also become a danger for public health. The use of wastewater for irrigation, in some cases, will increase the danger of rapid dissemination of the antibiotic resistant genes by enterococci. The aim of the present study was to determine different strains of enterococci in sewage treatment plants in Tehran, Iran, and their susceptibility to antibiotics.Material and methods: Samples collected four times from urban sewage treatment plant in Tehran between June 2005 and July 2006. Filtered samples were initially grown on mEnterococci medium containing 4mg/ml vancomycin. The isolates were identified by biochemical tests such as arabinose, argenine, growth at 45°C and NaCl 6.5%. All strains were then tested for their resistance against vancomycin, ampicillin, chloramphenicol, ciprofloxacin, erythromycin, tetracycline, streptomycin, amikacin and gentamycin and MIC were determined by microdilution broth test for vancomycm.Results: Of the 131 isolates resistance to 4 mg/ml vancomycin, 98 (75%) were identified as Enterococcus gallinarum, 24 (18%) as E. faecium and 9 (7%) as E. casseliflavus. There was a significant increase in the rate of resistance to all antibiotics (except chloramphenicol) among enterococci isolated during 2006 compared to 2005. Most of the samples were resistant to more than one antibiotic.Conclusion: The results showed that E.faecium and E. gallinarum were the most common species in the Tehran sewage treatment plant. E. casseliflavus showed the least prevalence. The results indicated that there was a significant increase in the rate of resistance to all antibiotics (except chloramphenicol) among enterococci isolated during 2006 compared to 2005. Our results may also suggest that the highly resistant glycopeptide E. gallinarum and E. casseliflavus in our study have captured plasmid containing resistant genes under natural conditions.