Performance of a land treatment system and vetiver plant for advanced treatment of ahvazwest Municipal wastewater treatment plant effluent

Background: During the last decades efforts related to waste water treatment, has improved significantly in Different places of our country with various climate conditions. To reach this aim using systems are considered that have appropriate applications technically and economically . One of the low cost and native options is using Land-plant system for advanced waste water treatment. The aim of this study was determination of efficiency of local soil of Ahvaz and vetiver plant tothe final reduce the organic load from Municipal wastewater treatment

Materials and Methods: In order to, a pilot including three Lysimeter swere installed in Ahvaz West wastewater treatment plant. ThreeLysimeter were utilized that local soil was used in one of them, local soil with vetiver plant were used in the other one and soil artificial arrangement local soil, silica sand [0.5-1mm], sand [15-30mm] was used in third Lysimeter. The effluent was transferred from Secondary settling outlet by pump for system that slow current in three filtration rate of 0.2, 0.6, 1 ml/min and three replication in each rate was used

Results: The average removal efficiency of BOD5 and COD output from three Lysimeter local soil with vetiver plant, local soil without vetiver plant and soil artificial arrangement for filtration rate of 0.2 ml/min were;73.27%, 68.39%,58.91%, 50.34%, 37.62% and 35.9%.For filtration rate of 0.6 ml/min were;49.47%,41.97%, 43.16, 28.31%, 33/68% and 25/55%.For filtration rate of 0.6ml/min; 26.44%,31.44%, 19.95,17.81%, 12.06% and 14.79%, respectively

Conclusion: The results from this study showed that the best removing percent was assigned to local soil with vetiver plant lysimeter in 0.2 ml/min current. Based on the results of this study, it can be concluded that a land- plant system as advanced treatment had the ability to meet effluent discharge permit limits and was an economical replacement for stabilization ponds and mechanical treatment options

Comparation of mono layer filter [Sand] dual media filter [anthracite and leca] and performance in removal of organic matter and turbidity

Improvement of water quality standards and inability of mono layer filters in producing such quality caused researchers attended to multi layer filters. Due to specific characteristics of anthracite and leca can improve removal of organic materials and Surface over flow rate. The aim of this research was evaluation performance of dual media filters [anthracite/leca] in removing of organic materials and turbidity from Ahvaz Water treatment plant. In this study two pilots built for investigation of mono layer filter and dual media filter performance. The researcher used sand in structure's media of mono layer filter and composition of anthracite, sand and leca in structure's media of dual media filter, respectively. In this study single and dual layer filter pilot examined in term of organic matter and turbidity removal efficiency. Results indicated that removal of organic matter by single layer filter [sand], dual media filter [anthracite, and sand], dual media filter [leca and sand] was 7%,12%,4/2% respectively. And also Turbidity removal by single layer filter [sand], dual media filter [anthracite and sand], dual media filter [leca and sand] was also 69%, 80%, 74% respectively. Results of this study showed that upgrading of Single layer to dual layer with anthracite and leca media can't show a significant affect in TOC removal

Survey of PAC performance for removal of turbidity, COD, coliform bacteria, heterotrophic bacteria from water of karoon river

Selection of proper coagulants for turbidity removal and determination of effective methods to reduce coagulants dose and related costs in water treatment plants is of critical importance. The present study investigates the effect of returned sludge on improving the performance of poly-aluminum chloride [PAC] in turbidity, coliform bacteria, heterotrophic bacteria removal from drinking water during rapid mixing phase. In order to determine the optimal returned sludge volume injected during rapid mixing with PAC for turbidity, total coliform and hetrophic bacteria, experiments were conducted based on variables such as injected silt volume [from 0-125 ml], and varying turbidities from 58 - 112 NTU. At the end of each JAR experiments, remaining turbidity, microbial parameters of samples were measured. Coagulant efficiency in turbidity removal and microbial parameters were determined by Covariance, Duncan analyses and graphs were drawn by MS Excel. The results statistically showed significant among variables [P<0.05]. The results showed that the maximum turbidity removal efficiency of 98.92 at 30 ppm was 10 ml while the maximum turbidity removal efficiency of 98.31 at 10 ppm was 4 ml. The maximum total coliform removal efficiency of 95.68 obtained for 10 ppm in 10 cc injected sludge volume. This study shows that addition of returned sludge to flash mixing can reduce the turbidity of samples

Investigation of intermittent chlorination system in biological excess sludge reduction by sequencing batch reactors

The excessive biological sludge production is one of the disadvantages of aerobic wastewater treatment processes such as sequencing batch reactors. To solve the problem of excess sludge production, oxidizing some of the sludge by chlorine, thus reducing the biomass coefficient as well as the sewage sludge disposal may be a suitable idea. In this study, two sequencing batch reactors, each with 20 L volume and controlled by on-line system were used. After providing the steady state conditions in the reactors, sampling and testing of parameters were done during 8 months. The results showed that during the solid retention time of 10 days the kinetic coefficient of Y and Kd were 0.58 mg biomass/mg COD and 0.058/day, respectively. At the next stage, different concentrations of chlorine were used in the reactors intermittently. Results showed that 15 mg chlorine/gMLSS in the reactor was able to reduce the yield coefficient from 0.58 to 0.3 mg biomass/mg COD. In other words, the biological excess sludge was reduced about 48%. But the soluble chemical oxygen demand increased slightly in the effluent and the removal percentage decreased from 95% in the blank reactor to 55% in the test reactor

[ study on biodegradability enhancement of landfill leachate by fenton oxidation]

Leachate is one of the landfill products and also a wastewater bearing the most advers effects on the environment. Biological methods are usually employed for treatment of young leachate [1-2 years] wich is of high concentration of organic compounds with low molecular weight. However these methods are not approprate for mature leachate [5-10years] due to having high rate of compounds with molecular weight and the presence of materials resistant to biodegradation and toxic compounds. Advanced oxidation process such as Fenton reagent used in treatment or biodegrability improvement of strong wastewater. In the present study the degrability improvement of mature leachate through oxidation fenton process in bench scale and in batch reactor has been investigated. The samples have been taken from Ahwaz landfill and factors such as initial COD and BOD, pH, BOD5/COD were studies as degradability, the amount of Hydrogen Peroxide, Fe[II], optimal reaction time and optimal pH. The highest amount of COD removal was observed in PH=3-3.5 and 90 minutes of reaction time. H2O2=29700mg/land Fe2+=16500 mg/l in [Fe2+]/[H2O2]=1/14.8 molarity ratio were obtained as optimal amounts BOD5/COD was equal to 0.38. This study indicates that Fenton oxidation enhances the biodegradability of leachate

efficiency of anaerobic digesters on Microbial quality of sludge in Isfahan and Shahinshahr waterwaste treatment plant

Anaerobic digestion is among the oldest processes used for stabilization of solid and biosolids. In this survey 12 samples were taken from the digested anaerobic sludge of Isfahan and ShahinShahr WWTP and total solids, volatile solids, total coliform, fecal coliform, Salmonella and viable parasite ova tests were done. Results were compared with the 503 sections of the 40 CFR regulation of the US EPA .The result showed that the average reduction rate was 30% for volatile solids, 4.5x107 MPN/g. dry solids [DS] for total coliform, 5.6x106MPN/g.DS for fecal coliform, 24MPN/4g.DS for Salmonella, and 27 number/4g.DS for viable parasite ova of digested anaerobic sludge in Isfahan. In Shahinshahr WWTP, the average of reduction was 39% in volatile solids, 2.13x 107MPN /g.DS in total coliform, 1.16x106 MPN /g.DS in fecal coliform ,11 MPN/4g.DS in Salmonella and 16 number/4g.DS for viable parasite ova of digested anaerobic sludge . Therefore the digested sludge in Isfahan did not meet the requirements of pathogen reduction in class A and B as well as the reduction requirements for vector attraction, while the digested sludge in ShahinShahr met the requirements of pathogen reduction in class B and vector attraction. So, agricultural use of digested sludge should be made by limiting the kind of crops as well as controlling the harvesting time. The results from the two anaerobic digesters of Isfahan and Shahin Shahr showed that there was a significance correlation between the reduction of volatile solids with total coliform, fecal coliform and Salmonella [P<0.05, r>0.9], while there was no significance correlation between the reduction of volatile solids and viable parasite ova