جستجوی مقالات مرتبط با کلیدواژه « حذف بیولوژیکی » در نشریات گروه « محیط زیست »

One of the consequences of industrial activities is the entry of toxic compounds such as cyanide into the environment, the neglect of which threatens the health of humans and other living organisms. The present study was performed to investigate the biological removal of cyanide from wastewater and to identify resistant microorganisms.

Artificial sewage Potassium by concentrations of 5, 20, 50, 100, 150 and 200 mg/l was studied in batch reactors with a capacity of 2 liters. Secondary sludge of Wastewater Treatment Plant with mixed media was used as the medium in reactor. Volatile suspended solid, total suspended solid, CN, NH3, NO3 factors were measured based on the standard method book. Rotifers, ciliates and algae were also identified using microscopy version IIS.

The results showed that biological treatment can remove cyanide up to concentration of 150 ppm and higher initial MLVSS played a main role in increasing removal of cyanide from sewage. Finally, Pseudomonas cyanide, coliforms (except fecal coliforms), bacillus, fungi and also Carchesium (one of ciliates), Philodina (one of rotifers) and Oscillatoria (one of algae) identified as resistant strains to cyanide and Aspidisca, Proals and Ulothrix detected as the most sensitive rotifers, ciliates and algae, respectively.

Results indicated that biological treatment of activated sludge for cyanide removal from sewage is an efficient way specially when substrate include only resistant microorganisms and can be consider as viable alternative for cyanide removal instead of chemical removal methods.

Proper management of sewage is one of the most important environmental issues, organic matter and nutrients, including phosphorus compounds, are the potential pollutants of the receiving waters. Release of phosphorus from municipal wastewater treatment plant effluent to the environment is one of the main reasons for the phenomenon of the Eutrophication. Therefore, the aim of this study was to determine the amount of nutrients and organic matter in wastewater of Yasouj city and efficient removal of nutrients such as total phosphorus by modified Bardenpho system.
This is a cross-sectional study. The sampling method as Composite Sampling and study population was samples of treatment system input (after screening system) and output of treatment system (after sedimentation). In order to identify of affecting factors on phosphorus removal use of modified Bardenpho pilot. The amount of nitrate, total phosphate, COD and BOD5 removal for 9 months was evaluated. The collected data were analyzed by using SPSS software (version 16).
Findings: According to the results, the average of input COD in system (674.55±228.54), input phosphorous (21.26±4.8), input nitrate (25.91±19.63), input BOD (378/33±106/66) mg per liter and the input pH (7.22±0.35). There is a significant Relationship between the input COD and percentage of phosphorus removal (P.value=0/004), but there is not significant relationship between the pH input and phosphorus removal percentage (P.value=0.339). Most phosphorus removal was observed in Solids Retention Time (SRT) of 15 days (69.72%). Internal recycle of 200 percent (68/96%) showed the highest percentage of phosphorous removal.
Discussion and According to obtained information, the optimum conditions for phosphorus removal showed SRT =15, HRT =0/5-1 in anaerobic tank, the internal recycle percentage of 200%, recycled activated sludge (75%) and keep the DO =2-3. Therefore, for removal of phosphorus addition of physical and chemical methods can use of modified biological processes. In this systems, by replacing of an anaerobic stage at the beginning of the process, improve phosphorus removal. This method can be a good alternative to treatment plants with activated sludge system.