Sharif Digital Repository

In this study biological denitrification method by moving bed biofilm reactor is investigated. The main advantage of MBBR reactor is due to their capacity for high removal rates and low operational problems such as clogging. Two MBBRs in series with 3 liter volume each, were designed in experimental set up and used in this research. Nitrification reactor worked under aerobic conditions and denitrification reactor operated under anaerobic conditions. Methanol was used as carbon source in the reactors throughout the study. Fifty percent of each reactor volume was occupied with KMT1 packing. To finding the optimum nitrate loading rate, the concentration of ammonium and nitrate were changed from... 

Different strategies for the treatment and disposal of petroleum and biological sludge found in the treatment and reuse unit of Arak Petroleum Refinery have been studied in the present study. To this end, the resources found in the literature corresponding to the different fields of sludge treatment were studied and a summary of them which was required by this research was mentioned in the thesis. Considering the problems bound to the wastewater treatment unit of this refinery plant and the previous studies, two completely separate strategies were devised. The first one concerns petroleum and biological sludge being produced continuously. The method of aerobic fixation of petroleum sludge by... 

Given that the most polluting industries in the country there. A suitable treatment system for degradation of these compounds is necessary unless unexpected effect on environment will occur.Moving Bed Biofilm Reactor (MBBR) was developed to adopt the best features of the activated sludge process as well as those of the biofilter processes. MBBR has biomass growth on carriers that move freely in the water volume of the reactor. High surface area of carriers make a good condition for biomass attached growth. This system has had good operation in the urban and some industrial wastewaters.In this study, four reactor volume of approximately 16 litr and 6, respectively, in the aerobic, anoxic... 

In recent years,because of increasing problems that result from water shortage ,using of wastewater treated by high quality and entering them to water cycle is considered more than past.Large amount of waste waterare produced through cooling towers in industries per a day .Therefore ,cooling tower’s blow down is a most important source for reclamation and reuse of water .The purpose of this project was investigation ofefficiency of submerged aerated filter for treating low organic simulated blowdown water as a feed . The experimental unit consisted of 8/5 L filled with 70 percent of propylene media . After obtaining steady –state condition ,The SAF reactor was tested under... 

Phenolic compounds are hazardous pollutants that are released into environment through wastewater discharges from variety of industries. Although good biodegradability has been reported at low concentrations, but at higher concentrations phenols are known to be antibacterial. In this study the Membrane Biological Reactor (MBR) with submerged hallow fiber membrane was operated at 25±2 ºC and pH=7.5±0.5 to treat a synthetic wastewater containing high phenol concentration (up to 5.9 g/l). Removal efficiency of phenol and COD were evaluated at four various “Hydraulic Retention Times” (HRT) of 24, 12, 8 and 4 hours. To test the tolerance of the bioreactor to phenol concentration various loading... 

Discharging treated or raw waste water in to surface water may cause lots of serious problems, including growth of algae, as a result of the presence of nutrients in waste water.algae decrease the concentration of dissolve oxygen in water.phosphorus removal from waste water is of absolute necessity. according to the standards set by the environmental organization, discharge the untreated waster water in to the surface water is not allowed. on the other hand, given manager facilities of deprived area,effort is channeled to reach the desired result through designing the simplest treatment systems. anaerobic-aerobic systems have remarkably been used for many years in the treatment of urban and... 

Antibiotic medications are widely used in medicine and veterinary medicine. Since these drugs are extremely dangerous to the environment and specially to drinking water for humans and other organisms, the need to treat these wastewater is becoming increasingly important. One of the most commonly used antibiotics is oxytetracycline which is used for a wide range of infectious diseases Husbandry wastewater is one of the wastewaters that contains high diversity and large amounts of antibiotics. In this study, the performance of a Moving bed biofilm reactor (MBBR) was investigated for removal of oxytetracycline from synthetic wastewater with similar characteristics to Husbandry wastewater. A... 

Greywater accounts for about 70% of household consumption and can be returned to the consumption cycle if a sustainable system is built in residential areas and the treated water can be used for irrigation, flash tank filling, and even aquifer fillings. The purpose of this study was to establish a sustainable method in small treatment plants that could sufficiently recover the water used in households. In this study, chemical ways of wastewater treatment, as well as membrane filtrations, were investigated to reduce greywater pollution. The results show that the coagulants alone can remove 80% of COD. Membranes can also reduce COD by up to 83%. In addition, the best removal efficiency using... 

Nowadays with the increasing population of the world and constraint or even water shortages, necessity of reuse the effluent of the treatment plants is further increased whearas the grey wastewater (wastewater related to bathroom, dishwasher and laundry). They are part of the household wastewater.quantity ranging from 65% to 75% sewage produced in the house is grey water. In many developed countries of the world the grey wastewater treatment and its use in non-potable wastewater like irrigation, car washing and toilet siphoning are commonplace. This wastewater is lower in COD and BOD than conventional wastewater but it still needs to be refined. There are varios methods including biological... 

In this study, the biological nitrogen removal process from a wastewater with high COD and TKN concentration was investigated in a hybrid reactor. In order to remove nitrogen completely with pre-denitrification process, both moving bed biofilm system and fixed bed biofilm system with pumice stone, were used in a single reactor (volume is 16 l). Moving bed biofilm and fixed bed biofilm systems were considered in sequence, as aerobic and anoxic parts of the reactor. 35% of the aerobic volume was occupied with plastic carriers and 70% of the anoxic volume was occupied with pumice stone with an average diameter of 30mm. Experiments were done in 7 runs, for total hydraulic retention times of 30,... 

One of the most important parts of bacteria growth is specific concentration of nutrients added. Although the trace amount of heavy metals are required for bacteria growth, after a threshold concentration they may cause damage or kill the bacteria. Scientifically speaking, all these trace nutrients should be consider as a profitable source of energy for bacteria growth. There are several studies throughout pondering whether the advantages of using heavy metals, such as Zn, outweigh the drawbacks. It has been proven that heavy metals, especially, zinc salt, can improve microbial growth up to a specific threshold concentration. In this study, two upward submerged aerated reactors, which had 12... 

Discharge of Raw wastewater or effluent of Treatment plants into the natural bodies of water, in the case of high nutrients may cause serious problems such as algae bloom which results in a reduction in concentration of dissolved oxygen. Among the nutrients, phosphorous is known as a limiting factor in growth and intensification (intensifier) of eutrophication. Therefore, elimination of phosphorus from wastewater prior to the discharge point is highly important. Phosphorus can be removed chemically as well as biologically. Chemical methods are known, efficient and reliable but Problems like operational and maintenance costs and chemical sludge production cause tendency to use biological... 

Atrazine is widely used in the agriculture as an herbicide. Due to its high mobility, Atrazine leaks into the groundwater, surface waters, and drinking water wells. Many physical and chemical methods have been suggested for removing Atrazine from aquatic environments. However, these methods are very costly, have many performance problems, produce a lot of toxic intermediates which are very harmful and dangerous, and cannot completely mineralize Atrazine. In this study, biodegradation of Atrazine by microbial consortium was evaluated in the aquatic environment. In order to assess the Atrazine removal from the aquatic environment, Fixed-Bed biofilm reactor and Moving Bed Biofilm Reactor were... 

Discharging wastewater effluents to water bodies has many detrimental impacts on water quality. Thus, to prevent issues such as eutrophication and oxygen depletion, nitrogen removal is often required in wastewater treatment plants. Biological nitrification and denitrification, in comparison to physical and chemical methods, is more cost-effective and environmentally friendly, and this makes it one of the most commonly used approaches for nitrogen removal. In this work, nitrification and denitrification process and the effect of sulphate on this process is studied in a moving bed biofilm reactor (MBBR). The method used is modified LUDZACK-ETTINGER (MLE) which has an initial denitrification... 

Heavy metals such as lead, chromium, nickel are considered as environmental pollutants. These substances are highly toxic and dangerous to humans and other organisms at low concentrations and many problems are caused by them. Chromium belongs to the group of heavy and toxic metals. Form 6-valent chromium for humans is considered a definite carcinogen and also creates other problems. One common method of chromium removal is chemical precipitation which caused a large volume of waste. Other methods such as ion exchange, solvent extraction, reverse osmosis and biological methods are used to remove chromium. Adsorption is another effective method with very few disadvantages compared to other... 

Today, with expanding industries, wastewater treatment of them is a global problem. Heavy metal is one of the most common and most dangerous contaminants in waste water that over time, with the strict standards of output, find more effective ways of eliminating them has always been a challenge. New methods, especially in the field of adsorption have achieved promising results in many cases.
Polymers composites are one of the adsorbent for the removal of these contaminants have been considered. In this project Aniline and composites to remove arsenic and chromium were studied. In polymers synthesis factors like type of additives and oxidizing materials strongly effected on morphology of... 

In this research the performance of the Moving Bed Biofilm Rector (MBBR) in different amounts of dissolved oxygen (DO) was investigated. Reactor with a useful volume of 15 liters was used in this study. In order to obtain optimum oxygen concentration, stayed at 6, 10 and 15 hours, and at different levels of dissolved oxygen in the range 0.5 -6 mg/lit, the amount of organic material was removed respectively. Also, in two different aeration intensity of 3.5 and 5.5 liters per minute at different values of e% (percentage of filling of media) the mass transfer coefficient values were obtained. When the aeration intensity increases from 3.5 to 5.5 liters per minute, and the percentage of 40%... 

Activated Carbon as a highly efficient and low price absorbent has manifold functions in separation and absorption processes in liquid or gas phases. These applications in liquid phase include bleaching in sugar syrup, water and wastewater treatment and in gas phase utilizing them in gas masks and solvent recycling process. Wide variety of base materials could be used to produce activated carbon. For instance rare cellulose materials -wood, coconut shell, Pyrenees and agricultural wastes-, carbon materials-coal, petroleum coke, tar- and polymer materials- tires and plastics wastes- could be mentioned. In this thesis, feasibility of producing activated carbon based on using walnut, almond... 

Soil nailing is a method of in situ reinforcement utilizing passive inclusions. It can be used to retain excavations and stabilize slopes by creating in situ, reinforced, soil retaining structures. This method has been used widely in recent years. Construction of a soil nail wall is performed in vertical steps, with construction starting at the top of the excavation and proceeding down. Once an excavated step is reinforced with soil nails, a permanent or temporary facing is then applied to retain the soil. Stepped soil nail wall is formed by setting a platform in the middle part of a typical soil nail wall.In this Thesis, behavior of a soil nail wall and a stepped soil nail wall are studied... 

Nitrogen compounds are becoming increasingly important in wastewater management. Due to several adverse effects which nitrogenous materials can have on the environment, there is a significant need for nitrogen removal. In this study, the biological nitrogen removal process from a wastewater with low COD was investigated in a submerged fixed bed reactor, constructed two anoxic and aerobic sections under Modified Ludzack-Ettinger process. Volume of each section was 10 liters. About 60% of each section was occupied with pumice stone.Experiments were conducted in 9 runs, for hydraulic retention times of 8, 6 and 4 hours, influent ammonia concentrations of 180, 90 and 30 mg/lit and recyle ratios...