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process that is used for the removal of dissolved constituents from wastewater remaining after
<br /> advanced treatment with tertiary filtration or microfiltration(Metcalf and Eddy,2003). RO Table 49: Microfiltration and Reverse Osmosis Cost Estimates by Ratepayer Group Allocation for
<br /> treatment relies on applied pressure to force water through a semi-permeable membrane while 21 MGD Treatment Capacity
<br /> restraining the passage of particulate and high molecular weight constituents. Membranes Annual
<br /> exclude ions,but require high pressures to produce the deionized water(Metcalf and Eddy, Annualized Operation and Total
<br /> 2003. Passage of water through the membrane produces a relatively ion free effluent stream and Capital Capital Maintenance Annual Project Life-
<br /> ) g g p y Ratepayer Group Costly,) Cost Costo) Cost Cycle Cost
<br /> a concentrated brine stream. MF occurs prior to RO in order to remove larger organic and
<br /> inorganic particles that foul the RO membrane and thus increase membrane resistance to water Current Residential $29,600,000 $2,600,000 $2,900,000 $5,500,000 $110,000,000
<br /> flow and reduce membrane service life. RO is a very energy intensive process that produces a Current Non- $19,700,000 $1,700,000 $1,900,000 $3,600,000 $72,000,000
<br /> toxic brine concentrate that poses its own waste disposal issues. In regard to pollutants of Residential
<br /> concern contained in WQCF effluent,RO would reduce concentrations of TDS,metals, Future Residential $51,200,000 $4,500,000 $5,000,000 $9,500,000 $190,000,000
<br /> ammonia,and organic compounds,and would lower EC. An estimated,future maximum Future Non-Residential $34,200,000 $3,000,000 $3,300,00 $6,300,000 $126,000,000
<br /> MF/RO capacity of 21 MGD considered in the current analysis is based on the volume of Totals $134,700,000 $11,800,000 $13,100,000 $24,900,000 $498,000,000
<br /> effluent that would require MF/RO treatment when the WQCF reaches its proposed build-out (1)Estimated March 2007 costs at ENRCCI 7856 based on 2004 costs provided in Camillo,2005(ENRCCI 7296).
<br /> capacity of 27 MGD(ADWF)in order to maintain TDS mass loadings in WQCF effluent at the (2)Project costs include engineering,administrative,legal,and contingency costs.
<br /> currently permitted 9.87 MGD(ADWF)level. MF/RO treatment of 21 MGD of WQCF effluent
<br /> would produce approximately 4.2 MGD of brine that would require disposal. This analysis
<br /> assumes that the blending of effluent streams of different qualities is permitted,and therefore Benefits
<br /> only a portion of WQCF tertiary effluent would need to undergo MF/RO prior to blending with MF/RO of a portion of WQCF tertiary treated effluent would provide sufficient removal of
<br /> non-MF/RO tertiary effluent subsequent to discharge to the San Joaquin River. pollutants of concern from blended MF/RO and non-MF/RO WQCF effluent discharged to the
<br /> San Joaquin River so as to maintain existing water quality and mass loading in the river at pre-
<br /> Costs project levels(i.e.,maintain water quality and mass loading at the currently permitted 9.87 MGD
<br /> The MF/RO costs provided in Table 49 are planning levels estimates that allow a cost (ADWF)level). However,it should be noted that MF/RO treatment would not significantly
<br /> comparison between the two treatment alternatives presented in this report. MF/RO cost lower downstream water quality concentrations in the receiving water.
<br /> estimates assumed 80 percent recovery for the treatment process with effluent making two passes
<br /> through membranes. The estimates include the on-site cost of controlled thermal evaporation or Potential Impacts
<br /> crystallization of brine,but do not include the off-site disposal of crystallized residuals. Advanced wastewater treatment employing MF/RO generates a significant level of concern due
<br /> Depending on the nature of the brine and residuals produced by MF/RO treatment of WQCF to energy demand and"cross media impacts"—this term refers to the interrelated impacts caused
<br /> effluent,the need for additional treatment to remove heavy metals and other toxic contaminants by removal of a pollutant from one medium and its transfer to one or more other media. In the
<br /> from the brine and/or limited disposal options of residuals could significantly increase the case of MF/RO,the process removes a pollutant at a certain concentration from wastewater and
<br /> ultimate cost of MF/RO above those costs provided herein. It should be emphasized that the cost partitions it at a significantly higher concentration in brine and/or residuals. Pollutants,such as
<br /> of crystallized brine residual disposal is not considered in this analysis and could result in metals,are not destroyed,but transferred from one medium to another. Organic pollutants can
<br /> significant additional costs and environmental compliance complexities if the crystallized waste be destroyed or converted to other toxic or non-toxic forms and can also be transferred from one
<br /> is not suitable for land disposal by traditional means. Table 49 presents various costs associated medium to another. It should be noted that in transferring from one medium to another,the
<br /> with the construction and operation of MF/RO facilities having a treatment capacity of 21 MGD. bioavailability of the pollutant may be changed significantly. MF/RO treatment results in the
<br /> In addition to total project costs,the costs of this alternative are divided among current and transfer of pollutants from wastewater into biosolids,air,and/or concentrated waste streams.
<br /> fixture ratepayers,and further subdivided among residential and non-residential customers. Depending on regulatory limits,additional treatment of the biosolids,air,or waste streams may
<br /> be required(Carollo,2005). In addition to these cross media pollutant transfer impacts,
<br /> operation of MF/RO processes can generate additional pollutants and greatly elevate local power
<br /> demand as described by the potential MF/RO environmental impacts provided in Table 50.
<br /> Finally,temporary,construction-related impacts associated with the building of MF/RO
<br /> treatment facilities are anticipated for this alternative control measure. However,these
<br /> temporary,construction-related impacts would be mitigated to the greatest extent practicable.
<br /> City of Manteca Antidegradation Analysis 103 June 2007 City of Manteca Antidegradation Analysis 104 June 2007
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