\nTreatment and Energy Recovery for Municipal Waste Water Using Forward Osmosis Process\u00a0\n<\/p>\n

\nTable of Contents\n<\/p>\n

\nBackground and motivation<\/a>
\n<\/h2>\n
\nMunicipal Wastewater Treatment<\/u>\n<\/p>\n
\nEvery day, millions of cubic meter of wastewater from homes, institutions, commercial and industries is flushed into the sewer system. Municipal wastewater contain sanitary sewage and sometimes it even contain stormwater. Municipal wastewater is one of the largest source of pollution in water in Canada (Government of Canada).\n<\/p>\n
\n $\"\"$
\n<\/img><\/p>\n
\nFigure:1<\/strong> Water treatment level 1983 \u2013 2009.\n<\/p>\n
\n(Adopted from Municipal wastewater treatment- Canada)\n<\/p>\n
\nThe operating condition and methodology depends on the level of effluents. Pretreatment, Primary treatment, secondary treatment, tertiary treatment and haulage are the main treatment process followed by the wastewater treatment plants. The percentage of Canadians on municipal sewers with secondary treatment has improved from 40% in 1983 to 69% in 2009, which is approximately 18% done by primary treatment and 13 % by household septic tanks (Government of Canada). Pretreatment removes solid particles while primary treatment reduces the amount of organic solids and inorganic solids.\n<\/p>\n
\nCompared to these process the secondary treatment and advanced treatment methods require more energy as they have to remove phosphorous, nitrogen and organic matter up to certain extent. Biological treatment is a part of secondary treatment in which dissolved oxygen is added to\u00a0 remove organic impurities by removing impurities and disinfecting them. Usually, secondary process are designed in such a way that it remove 20-35% 0f nitrogen and 80-95% of BOD_{5 <\/sub>from wastewater.\n<\/p>\n}
\nTertiary and advanced treatment methods remove the remaining suspended solids and pathogenic microorganisms.\n<\/p>\n
\nForward osmosis <\/u>\n<\/p>\n
\nVarious methods are being studied for the treatment of wastewater; out of which osmotic membrane technology is being researched to produce\u00a0 energy and desalinate water. The phenomenon of forward osmosis occur when water begin to move from feed solution to draw solution to reach osmotic equilibrium. Here the\u00a0 municipal wastewater is termed as feed solution and seawater as draw solution. Feed solution has low osmotic pressure while the draw solution has high pressure. FO do not require any hydraulic pressure as an input energy, instead it work on osmotic pressure of the solution which create osmotic gradient. The membrane separates the two solution and behaves as a physical barrier for suspended solids and many salts. The figure below shows a the flow of the forward osmosis process. $\"\"$
\n<\/img><\/p>\n
\nFigure 2<\/strong>: Flow of forward osmosis process\n<\/p>\n
\nForward Osmosis Theory <\/u>\n<\/p>\n
\nAssume that the following equation completely rejects the feed and draw solute and water transport through a FO membrane is generally described as:\n<\/p>\n
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 J_{W = <\/sub>A(\uf050_{D,b <\/sub>\u00a0– \uf050_{F,b<\/sub>)\n<\/p>\n}}}
\nWhere,\n<\/p>\n
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 J_{w <\/sub>\u00a0is the water flux\n<\/p>\n}
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A is the pure water permeability of the membrane\n<\/p>\n
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \uf050_{D,b <\/sub>\u00a0is the bulk osmotic pressure of draw solution and,\n<\/p>\n}
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \uf050 _{F,b<\/sub> is the bulk osmotic pressure of the feed solution.\n<\/p>\n}
\nThe bulk osmotic pressure is given by Van\u2019t Hoff\u00a0 equation for both the solution:\n<\/p>\n
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \uf050 = R_{g <\/sub>T \uf053 i M\n<\/p>\n}
\n\u00a0 Where,\n<\/p>\n
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 R_{g<\/sub> is a gas constant\n<\/p>\n}
\nT is the temperature in Kelvin\n<\/p>\n
\nI is the Van\u2019t Hoff factor for specific ion\n<\/p>\n
\nM is the molarity of the specific ion.\n<\/p>\n
\nConcentration polarization<\/u>\n<\/p>\n
\nAs water passes through the membrane, the surface of the membrane is blocked by the solute facing the feed solution which cause the pressure on the surface of the feed solution to be larger compared to the osmotic pressure of the bulk feed solution. This phenomenon is termed as concentrative external concentration polarization for a dense symmetric membrane ( McCutcheon and Elimelech 2007). It is given by\n<\/p>\n
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 J_{w<\/sub> = A( \uf050_{D,b <\/sub>\u2013 \uf050_{F,b <\/sub>exp (J_{w,e<\/sub>\/ K_{f<\/sub>))\n<\/p>\n}}}}}
\nThe exponential term is the concentrative ECP modulus and is the function of J_{w,e <\/sub>.\n<\/p>\n}
\nJ_{w,e <\/sub>\u00a0is water flux and K_{f<\/sub> is the mass transfer coefficient on the feed side of the membrane.\n<\/p>\n}}
\nOn the draw solution side of the membrane dilutive ECP takes place. The water that passed through the membrane weakens the effective draw solution osmotic pressure at the membrane surface. The equation for the combination of both the phenomena is given as under:\n<\/p>\n
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 J_{w <\/sub>= A(\uf050_{D,b<\/sub> exp (-J_{w,e<\/sub>\/ K_{D<\/sub>) \u2013 \uf050_{F,b<\/sub> exp (J_{w,e<\/sub>\/ K_{F<\/sub>))\n<\/p>\n}}}}}}}
\nWhere,\n<\/p>\n
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 K_{D<\/sub> is the mass transfer coefficient on the draw solution side of the membrane.\n<\/p>\n}
\n\u00a0The negative sign\u00a0 at the dilutive ECP modulus indicates the reduction of the osmotic pressure on the draw solution side. The above equation is for dense symmetric membrane while FO system works effective using asymmetric membrane i.e., porous support layer and dense layer. However, in FO the concentration inside the membrane has larger effect on water flux.\n<\/p>\n
\nInternal concentration polarization (ICP) is caused when the salts get accommodated in the porous support layer. The draw solution is in contact with the porous layer. The salt which is on porous layer should allow\u00a0 to generate the osmotic driving force. Once it is generated the water will pass through the membrane and as a result it will decrease the concentration of the draw solution. The dilutive effect in the membrane is referred to as dilutive ICP and is given as:\n<\/p>\n
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 J_{w <\/sub>= A(\uf050_{D,b<\/sub> exp (-J_{w,e<\/sub> K_{D<\/sub>) \u2013 \uf050_{F,b<\/sub> exp (J_{w,e<\/sub>\/ K_{F<\/sub>))\n<\/p>\n}}}}}}}
\nWhere,\n<\/p>\n
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 exp (-J_{w,e<\/sub> K_{D<\/sub>) is the dilutive ICP modulus and,\n<\/p>\n}}
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 k is the resistance to the diffusion by the solute\n<\/p>\n
\nSolute Transport<\/u>\n<\/p>\n
\nIn ideal case of forward osmosis membrane completely block the way of salts; but with current FO reverse salt diffusion is going to happen. Due to this, it is increases the risk to the economy of industrial FO system. If NaCl transfer across the membrane it will be against the strict water quality standards.\u00a0 Furthermore, the bidirectional transfer of the solutes must be considered. For an example, the transfer of solutes like pathogens and other organic compound from wastewater treatment\u00a0 to treated salt water may not meet the water quality standards. An equation to predict the amount of reverse salt diffusion is given by (Philip and Yong 2010):\n<\/p>\n
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 J_{w <\/sub>\/ J_{s<\/sub> = A\/B nR_{g<\/sub>T\n<\/p>\n}}}
\nWhere,\n<\/p>\n
\nJ_{s <\/sub>\u00a0is the total draw solute flux\n<\/p>\n}
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 B is the draw solute permeability coefficient\n<\/p>\n
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 N is the number of dissolved species\n<\/p>\n
\nFouling concerns<\/u>\n<\/p>\n
\nMembrane fouling is a general problem in FO. It occur mainly due to two reasons (1) organisms use the membrane to attach themselves to (2) due to hydrodynamic force of an osmosis system foultants are drawn into membrane. It decreases the speed of flow rate across the membrane. There are several ways to reduce the effect of fouling like backflushing, increasing the cross-section area, pretreatment and chemical cleaning.\n<\/p>\n
\nRecent Developments and advantages<\/u>\n<\/p>\n
\nTreating complex water like municipal wastewater using forward osmosis membrane has increased over 12 years (Cath 2006; Achilli 2009; Buckwalter 2013 and Ansari 2017). Many of the significant discoveries related to the wastewater treatment using FO membrane and algae separation as described below.\n<\/p>\n
\n(1)\u00a0\u00a0 No need for pre-treatment\n<\/p>\n
\n(2)\u00a0\u00a0 Low energy required due to lack of hydraulic pressure needed.\n<\/p>\n
\n(3)\u00a0\u00a0 As the pore radius is between 0.25-0.37 nm, there is high rejection of salt, pathogens and TDS.\n<\/p>\n
\n(4)\u00a0\u00a0 The process holds excellent working records in terms of durability and water quality.\n<\/p>\n
\n(5)\u00a0\u00a0 The process is easy to apply and very flexible.\n<\/p>\n
\n(6)\u00a0\u00a0 Membrane replacement rates are less\n<\/p>\n
\nDisadvantages<\/u>\n<\/p>\n
\n(1)\u00a0\u00a0 Low water fluxes and reverse salt diffusion\n<\/p>\n
\n(2)\u00a0\u00a0 Incomplete rejection of organic contaminants\n<\/p>\n
\n(3)\u00a0\u00a0 Low water flux\n<\/p>\n
\nBioenergy from algae<\/u>\n<\/p>\n
\nMicroalgae have a simple cellular structure. They are the plants which do not have roots, stems and leaves containing chlorophyll. Algae carry out photosynthesis by using solar system to split water and fix carbon dioxide which gives oxygen and storable chemical energy as output. Microalgae have the potential to decrease the water footprint of biofuel production. $\"\"$
\n<\/img><\/p>\n
\nFigure 3<\/strong>: Comparison of microalgae\u2019s footprint to other crops\n<\/p>\n
\n(adapted from Yang, 2011)\n<\/p>\n
\nAccording to new findings algae biofuel could compete with conventional energy production if wastewater is utilized as water resource. Anaerobic digestion is a biological process used to convert biodegradable materials into methane and carbon dioxide. Compared to normal electricity production costs, anaerobic digestion of microalgae using wastewater produce energy at high cost.\n<\/p>\n
\nDuring the process, the organic material is broken down into insoluble organic polymers. Acidogenic bacteria break the sugars and amino acids into carbon dioxide, ammonia, hydrogen and organic acids. Acidogenic bacteria further breaks organic acids into ammonia and carbon dioxide. Lastly, methanogens convert the remaining products into carbon dioxide and methane that can be used for bioenergy production.\n<\/p>\n
\nBioenergy produced from wastewater has two benefits. (1) Sufficient concentration of nitrogen, phosphorous, carbon, etc. are present in the abundant amount in wastewater.\n<\/p>\n
\n(2) There is no need to construct a new infrastructure to transport wastewater to centralized wastewater treatment plant.\n<\/p>\n
\nThe only drawback of this process is to use algae to supply oxygen and remove nutrients is the removal. According to a study 20-40% of the total algae production cost is due to separation of algae from its aqueous environment ( Grima 2003; Pragya, Sahoo 2013). Harvesting microalgae by FO might be less expensive than other methods, only if the leakage through membrane is controlled and seawater is readily available (Buckwalter 2013).\n<\/p>\n
\nMethod<\/a>
\n<\/h3>\n
\nThis section describes the source of data, the necessary assumptions and the economic theory to study the feasibility of the process economically.\n<\/p>\n
\nForward osmosis system<\/u>\n<\/p>\n
\nForward osmosis process have following components: a housing structure, feed pumps, storage tanks, flush pumps, FO membrane, valves, piping structure, hangers, FO instrumentation and control system. The FO system was designed based on the advanced treatment system using the reverse osmosis for the wastewater treatment (AWP 2013). The working of the system is shown below by flow diagram.\n<\/p>\n
\nWastewater is termed as feed solution and the seawater is termed as a draw solution. Both the solution enter the FO system and are stored in a tank so that the flow is gravitational flow. To prevent both the solutions sulfuric acid and antiscalant is added to them. Feed pumps are used to pump both solutions across the forward osmosis membranes. We get diluted seawater or a concentrated algae when both the solution exit the membrane. Once a month, the flush pumps are used to remove fouling from the membrane. The figure below shows the flow diagram of forward osmosis system.\n<\/p>\n
\n $\"\"$ \n<\/p>\n
\nFigure 4: <\/strong>Flow diagram of forward osmosis process.\n<\/p>\n
\n(Adapted from thesis by Patrick Buckwalter, 2017)\n<\/p>\n
\nAssumptions, parameters and cost<\/strong>\n<\/p>\n
\nSystem operation parameters<\/u>\n<\/p>\n\n\n\n\n
\n
\nSystem parameter<\/em>\n<\/p>\n<\/td>\n
\n
\nValue<\/em>\n<\/p>\n<\/td>\n
\n
\nUnits<\/em>\n<\/p>\n<\/td>\n
\n
\nReference<\/em>\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nSystem size\n<\/p>\n<\/td>\n
\n
\n1\n<\/p>\n<\/td>\n
\n
\nMGD\n<\/p>\n<\/td>\n
\n<\/td>\n<\/tr>\n
\n
\nPlant life\n<\/p>\n<\/td>\n
\n
\n20\n<\/p>\n<\/td>\n
\n
\nyears\n<\/p>\n<\/td>\n
\n<\/td>\n<\/tr>\n<\/table>\n
\nForward osmosis operating inputs<\/u>\n<\/p>\n\n\n\n\n\n\n\n\n\n
\n
\nSystem parameter<\/em>\n<\/p>\n<\/td>\n
\n
\nValue<\/em>\n<\/p>\n<\/td>\n
\n
\nUnits<\/em>\n<\/p>\n<\/td>\n
\n
\nReference<\/em>\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nFO membrane replacement\n<\/p>\n<\/td>\n
\n
\n5\n<\/p>\n<\/td>\n
\n
\nyears\n<\/p>\n<\/td>\n
\n
\nLinares, 2016\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nMembrane water Flux\n<\/p>\n<\/td>\n
\n
\n5\n<\/p>\n<\/td>\n
\n
\nL m^{-2 <\/sup>hr^{-1<\/sup>\n<\/p>\n<\/td>\n}}
\n
\nWang, 2016\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nUsable membrane module area\n<\/p>\n<\/td>\n
\n
\n9\n<\/p>\n<\/td>\n
\n
\nm^{2<\/sup>\n<\/p>\n<\/td>\n}
\n
\nKim, 2015\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nConcentration factor\n<\/p>\n<\/td>\n
\n
\n5\n<\/p>\n<\/td>\n
\n
\nn\/a\n<\/p>\n<\/td>\n
\n
\nWang, 2016\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nFeed\/ Draw flow rate\n<\/p>\n
\nratio\n<\/p>\n<\/td>\n
\n
\n1:1\n<\/p>\n<\/td>\n
\n
\nn\/a\n<\/p>\n<\/td>\n
\n
\nHancock and Cath, 2009\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nMembrane cleaning rate\n<\/p>\n<\/td>\n
\n
\n2\n<\/p>\n<\/td>\n
\n
\n#\/month\n<\/p>\n<\/td>\n
\n
\nWang, 2016\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nEnergy consumption\n<\/p>\n<\/td>\n
\n
\n0.23\n<\/p>\n<\/td>\n
\n
\nkWh\/m^{3<\/sup>\n<\/p>\n<\/td>\n}
\n
\nJackson, 2014\n<\/p>\n<\/td>\n<\/tr>\n<\/table>\n
\nCapital Cost assumption<\/u>\n<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
\n
\nSystem parameter<\/em>\n<\/p>\n<\/td>\n
\n
\nValue<\/em>\n<\/p>\n<\/td>\n
\n
\nUnits<\/em>\n<\/p>\n<\/td>\n
\n
\nReference<\/em>\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nMembrane cost\n<\/p>\n<\/td>\n
\n
\n$56\n<\/p>\n<\/td>\n
\n
\nm^{-2<\/sup>\n<\/p>\n<\/td>\n}
\n<\/td>\n<\/tr>\n
\n
\nForward Osmosis Facility structure\n<\/p>\n<\/td>\n
\n
\n$2,653,680\n<\/p>\n<\/td>\n
\n
\n21.2 MGD\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nFO feed pump\n<\/p>\n<\/td>\n
\n
\n$1,153,144\n<\/p>\n<\/td>\n
\n
\n21.2 MGD\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nFO Flush pump\n<\/p>\n<\/td>\n
\n
\n$96,847\n<\/p>\n<\/td>\n
\n
\n21.2 MGD\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nTank\n<\/p>\n<\/td>\n
\n
\n$191,517\n<\/p>\n<\/td>\n
\n
\n21.2 MGD\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nHangers and supports\n<\/p>\n<\/td>\n
\n
\n$127,910\n<\/p>\n<\/td>\n
\n
\n21.2 MGD\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nValves\n<\/p>\n<\/td>\n
\n
\n$634,422\n<\/p>\n<\/td>\n
\n
\n21.2 MGD\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nPiping\n<\/p>\n<\/td>\n
\n
\n$132,652\n<\/p>\n<\/td>\n
\n
\n21.2 MGD\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nInstrumentation and controls (I & C)\n<\/p>\n<\/td>\n
\n
\n8\n<\/p>\n<\/td>\n
\n
\n%\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nPermitting\n<\/p>\n<\/td>\n
\n
\n$25,000\n<\/p>\n<\/td>\n
\n
\n4 MGD\n<\/p>\n<\/td>\n
\n
\nLundquist, 2010\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nMobilization\/ demobilization\n<\/p>\n<\/td>\n
\n
\n$452,500\n<\/p>\n<\/td>\n
\n
\n4 MGD\n<\/p>\n<\/td>\n
\n
\nLundquist, 2010\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nConstruction Insurance\n<\/p>\n<\/td>\n
\n
\n$181,500\n<\/p>\n<\/td>\n
\n
\n4 MGD\n<\/p>\n<\/td>\n
\n
\nLundquist, 2010\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nEngineering, Legal & Administration\n<\/p>\n<\/td>\n
\n
\n$317,500\n<\/p>\n<\/td>\n
\n
\n4 MGD\n<\/p>\n<\/td>\n
\n
\nLundquist, 2010\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nConstruction Management\n<\/p>\n<\/td>\n
\n
\n$545,000\n<\/p>\n<\/td>\n
\n
\n4 MGD\n<\/p>\n<\/td>\n
\n
\nLundquist, 2010\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nContingency\n<\/p>\n<\/td>\n
\n
\n$452,500\n<\/p>\n<\/td>\n
\n
\n4 MGD\n<\/p>\n<\/td>\n
\n
\nLundquist, 2010\n<\/p>\n<\/td>\n<\/tr>\n<\/table>\n
\nAnnual Operation Cost Assumptions\n<\/p>\n\n\n\n\n\n\n\n\n\n\n
\n
\nSystem parameter<\/em>\n<\/p>\n<\/td>\n
\n
\nValue<\/em>\n<\/p>\n<\/td>\n
\n
\nUnits<\/em>\n<\/p>\n<\/td>\n
\n
\nReference<\/em>\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nFO Feed Pump\n<\/p>\n<\/td>\n
\n
\n$333,301\n<\/p>\n<\/td>\n
\n
\n21.2 MGD\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nFO Flush pump\n<\/p>\n<\/td>\n
\n
\n$178\n<\/p>\n<\/td>\n
\n
\n21.2 MGD\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nAntiscalant Feed pump\n<\/p>\n<\/td>\n
\n
\n$1,119\n<\/p>\n<\/td>\n
\n
\n21.2 MGD\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nSulfuric acid feed pump\n<\/p>\n<\/td>\n
\n
\n$1,119\n<\/p>\n<\/td>\n
\n
\n21.2 MGD\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nAntiscalant\n<\/p>\n<\/td>\n
\n
\n$132,359\n<\/p>\n<\/td>\n
\n
\n21.2 MGD\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nSulfuric Acid\n<\/p>\n<\/td>\n
\n
\n$298,191\n<\/p>\n<\/td>\n
\n
\n21.2 MGD\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nMaintenance cost\n<\/p>\n<\/td>\n
\n
\n$851,458\n<\/p>\n<\/td>\n
\n
\n21.2 MGD\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nLabor cost\n<\/p>\n<\/td>\n
\n
\n$1,418,271\n<\/p>\n<\/td>\n
\n
\n21.2 MGD\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n<\/table>\n
\nEconomic rate assumption\n<\/p>\n\n\n\n\n\n
\n
\nSystem parameter<\/em>\n<\/p>\n<\/td>\n
\n
\nValue<\/em>\n<\/p>\n<\/td>\n
\n
\nUnits<\/em>\n<\/p>\n<\/td>\n
\n
\nReference<\/em>\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nElectricity cost\n<\/p>\n<\/td>\n
\n
\n$0.12\n<\/p>\n<\/td>\n
\n
\nkWh\n<\/p>\n<\/td>\n
\n
\nAWP 2013\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nInflation rate\n<\/p>\n<\/td>\n
\n
\n3\n<\/p>\n<\/td>\n
\n
\n%\n<\/p>\n<\/td>\n
\n
\nHickenbottom, 2015\n<\/p>\n<\/td>\n<\/tr>\n
\n
\nDiscount rate\n<\/p>\n<\/td>\n
\n
\n6\n<\/p>\n<\/td>\n
\n
\n%\n<\/p>\n<\/td>\n
\n
\nGomez 2011\n<\/p>\n<\/td>\n<\/tr>\n<\/table>\n
\nAll the above tables are taken from the thesis presented by Patrick Buckwalter.\n<\/p>\n
\nCost analysis of FO system<\/u>\n<\/p>\n
\nThe main assumption in the design is that it is similar to the design of reverse osmosis process. The components which are necessary in RO for hydraulic pressure are omitted. System design, operational costs and membrane componentry are proposed based on advanced water purification facility study report (AWPFSR) using reverse osmosis process (AWP 2013).\n<\/p>\n
\nFO membrane cost is taken as $1500 per 27 m^{2<\/sup> (Linares 2016).\n<\/p>\n}
\n\u00a0 Cost of the membrane (FO_{cost<\/sub>) = A_{FO <\/sub>\uf02a C_{m<\/sub>\n<\/p>\n}}}
\n_{\u00a0 <\/sub>Where, A_{FO <\/sub>is the area of membrane\n<\/p>\n}}
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 C_{m<\/sub> is the cost of membrane per square meter.\n<\/p>\n}
\nMembrane area can be given as:\n<\/p>\n
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A_{FO<\/sub> = Q_{FS <\/sub>\/ J_{w<\/sub>\n<\/p>\n}}}
\nWhere, Q_{FS <\/sub>\u00a0is the membrane permeation rate of feed solution\n<\/p>\n}
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 J_{w<\/sub> is the water flux through the membrane.\n<\/p>\n}
\nCosts associated with the pumping and pretreatment were taken double the cost of reverse osmosis process as the FO system require two flow streams across the membrane.\n<\/p>\n
\nCost of construction, engineering, permitting, legal, Construction management\u00a0 was taken from a report by Lundquist, 2010.\n<\/p>\n
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Results and discussion<\/strong>\n<\/p>\n
\nInitial capital cost of the FO system was about $3.2 million dollars per million gallons of capacity. It is broken down into various compartments. Membrane cost is the largest cost contributor with $2,000,000 for 32,000 m^{2<\/sup> of membrane. Indirect costs include engineering, construction, legal and administration. \n<\/p>\n}
\nFigure 5: Capital cost components for forward osmosis system (Buckwalter, 2017)\n<\/p>\n
\nAnnual operational cost for the system is about $600,000 per one million gallons of the capacity per year. Osmosis replacement cost is largest contributor to annual operations cost. Compared to other technologies like microfiltration, activated carbon; FO\u00a0 provides an estimated cost of construction, operation and maintenance.\n<\/p>\n
\n $\"\"$ \n<\/p>\n
\nFigure 6: Operational cost break down of forward osmosis system (Buckwalter, 2017)\n<\/p>\n
\nConclusion\n<\/p>\n
\nForward osmosis process is not only an advanced wastewater treatment technology but it can simultaneously harvest algae for biofuel and reduce the volume of the wastewater. The FO facility was found to have a lifecycle cost of approximately $10 million\/MGD of feed solution.\n<\/p>\n
\nAll in all, forward osmosis concept using feed and draw solution can be considered as a future wastewater treatment concept.\n<\/p>\n
\nFuture Work<\/strong><\/a>\n<\/p>\n
\nFollowing is the future work to be carried out for this system:\n<\/p>\n
\n(1)\u00a0\u00a0 To remove the total nitrogen demand for large wastewater treatment plants, the solute rejection of ammonium should be rejected and for that membrane improvement becomes necessary.\n<\/p>\n
\n(2)\u00a0\u00a0 Mechanical pre-treatment for the FO process should be investigated\u00a0 for its operational and economic advantages and disadvantages.<\/p>\n
\nReferences<\/strong>\n<\/p>\n
\n
\nAchili, Andrea and Amy Childress. 2009<\/strong>. \u2018The forward osmosis membrane bioreactor: a low fouling alternative to MBR processes\u2019 Desalination.\n<\/li>\n
\nAnsari, Ashley J, William E Price, Jorg E Drewes, and Long D Nghiem. 2017<\/strong>\n<\/li>\n
\n\u2018Forward osmosis as a platform for resource recovery from municipal wastewater\u2019 Journal of membrane science.\n<\/li>\n
\nAdvanced<\/strong>\u00a0 <\/strong>Water Purification Facility Study Report <\/strong>(AWP), San Diego Water Purification Demonstration Project. 2013. \u2018 Indirect Potable Reuse\/ Reservoir Augmentation Demonstration Project Advanced Water Purification Facility.\u2019\n<\/li>\n
\nBuckwalter, Patrick; Shrewin Gormly, and Jonathan D Trent. 2013<\/strong>. \u2018 Dewatering microalgae by forward osmosis\u2019, Desalination.\u2019\n<\/li>\n
\nBuckwalter, Patrick. 2017<\/strong>. \u2018Forward osmosis for Wastewater Treatment and energy recovery.\u2019\n<\/li>\n
\nCath, Tzahi y, Amy E Childress, and Menachem Elimelech. 2006<\/strong>.\u2019 Forward osmosis: Principles, applications, and recent developments\u2019, Journal of membrane science.\n<\/li>\n
\nCornelissen, ER, CJ Ruiken, Jian-Jun Qin, H Oo, and LP Wessels. 2008<\/strong>. \u2018 Membrane fouling and process performance of forward osmosis membranes on activated sludge\u2019, Journal of membrane science.\n<\/li>\n
\nDemirbas, Ayhan, and M Fatih Demirbas. 2011.<\/strong> \u2018Importance of algae oil as a source of biodiesel\u2019, Energy conservation and management.\n<\/li>\n
\nGomez, J. 2011<\/strong> \u2018 Assessment of osmatic Mechanisms Pairing Desalination Concentrate and Wastewater treatment\u2019, Texas Water Development Board.\n<\/li>\n
\nGrima, E Molina, A Robles Medina, and Yusuf Chisti. 2003<\/strong>. \u2018 Recovery of microalgal biomass and metabolites: process option and economics\u2019, Biotechnology Advances.\n<\/li>\n
\nHancock and Cath. 2009<\/strong>. Solute coupled diffusion in osmotically driven membrane processes\u2019, Environmental science and technology.\n<\/li>\n
\nHickenbottom and Tzahi Y Cath. 2015.<\/strong> \u2018Assessing the current state of commercially available membranes and spacers for energy production with PRO: An experimental investigation\u2019, development and assessment of a novel osmotic heat engine for energy generation from low-grade heat.\n<\/li>\n
\nJackson, M., 2014<\/strong>. Evaluation of an osmotic dilution process for tertiary wastewater treatment. Master Thesis, Humboldt State University.\n<\/li>\n
\nKim, Jung Eun, Sherub Phuntsho, Fezeh Lotfi, and Ho Kyong Shon. 2015.<\/strong> \u2018Investigation of pilot-scale 8040 FO membrane module under different operating conditions for brackish water desalination\u2019, Desalination and Water Treatment.<\/em>\n<\/li>\n
\nLinares, Rodrigo Valladares, Zhenyu Li, Muhannad Abu-Ghdaib, Chun-Hai Wei, Gary Amy, and Johannes S Vrouwenvelder. 2013.<\/strong> \u2018Water harvesting from municipal wastewater via osmotic gradient: an evaluation of process performance\u2019, Journal of membrane science.<\/em>\n<\/li>\n
\nLundquist, Tryg J, Ian C Woertz, NWT Quinn, and John R Benemann. 2010.<\/strong> \u2018A realistic technology and engineering assessment of algae biofuel production\u2019, Energy Biosciences Institute<\/li>\n
\nMcCutcheon, Jeffrey R, Robert L McGinnis, and Menachem Elimelech. 2005.<\/strong> \u2018A novel ammonia-carbon dioxide forward (direct) osmosis desalination process\u2019, Desalination.\n<\/li>\n
\nPhillip, William A, Jui Shan Yong, and Menachem Elimelech. 2010.<\/strong> \u2018Reverse draw solute permeation in forward osmosis: modeling and experiments\u2019, Environmental science & technology.\n<\/li>\n
\nPragya, Namita, Krishan K Pandey, and PK Sahoo. 2013<\/strong>. \u2018A review on harvesting, oil extraction and biofuels production technologies from microalgae\u2019, Renewable and Sustainable Energy Reviews.\n<\/li>\n
\nWang, Zhiwei, Junjian Zheng, Jixu Tang, Xinhua Wang, and Zhichao Wu. 2016.<\/strong> \u2018A pilot-\n<\/li>\n
\nscale forward osmosis membrane system for concentrating low-strength\n<\/li>\n
\nmunicipal wastewater: performance and implications\u2019, Scientific reports <\/em>\n<\/li>\n
\nYang, Jia, Ming Xu, Xuezhi Zhang, Qiang Hu, Milton Sommerfeld, and Yongsheng <\/strong>\n<\/li>\n
\nChen. 2011<\/strong>. \u2018Life-cycle analysis on biodiesel production from microalgae: water\n<\/li>\n
\nfootprint and nutrients balance\u2019, Bioresource technology.\n<\/li>\n<\/ul>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
Treatment and Energy Recovery for Municipal Waste Water Using Forward Osmosis Process\u00a0 Table of Contents Abstract TREATMENT AND ENERGY RECOVERY FOR MUNICIPAL WASTE WATER\u00a0\u00a0\u00a0 USING FORWARD OSMOSIS PROCESS Background and motivation Method Future Work References Footnotes Tables Figures Abstract Treatment of wastewater has become necessary and treatment using membrane is flourishing widely. Forward osmosis process is one such process. The main aim of this study […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[121],"tags":[77222],"class_list":["post-254059","post","type-post","status-publish","format-standard","hentry","category-environmental-sciences","tag-treatment-and-energy-recovery-for-municipal-waste-water-using-forward-osmosis-process"],"_links":{"self":[{"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/posts\/254059"}],"collection":[{"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/comments?post=254059"}],"version-history":[{"count":0,"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/posts\/254059\/revisions"}],"wp:attachment":[{"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/media?parent=254059"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/categories?post=254059"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/glowriters.com\/wp-json\/wp\/v2\/tags?post=254059"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}