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i <br /> Removing Total Organic Carbon from Wastewater a <br /> rejecting compounds of lower molecular Hydrogen <br /> weight, including some forms of TOC and total Peroxide <br /> dissolved solids(TDS),than are NF membranes. <br /> Filtration must be conducted in advance of RO <br /> and NF membranes to protect membrane Treated <br /> integrity. MF and OF membranes are routinely Wastewater a <br /> used for this purpose (Snyder et al, 2007; affluent <br /> Drewes et al, 2008). Figure 3 presents the <br /> typical configuration of a membrane filtration LIV <br /> process. REACTOR <br /> MEMBRANE Figure 4. Typical Advanced Oxidation Process ` <br /> MODULES Using UV/Peroxide <br /> carbon dioxide and water. The energy that ) <br /> Pretreatment would be required to mineralize the TOC to <br /> chemicals . below 3.0 or 1.0 mg/L would be cost <br /> Treated 1--o prohibitive; as a result, advanced oxidation h <br /> wEffluente7 alone is not recommended for reducing TOC 3 <br /> s <br /> Pump Post- concentrations. However, advanced oxidation <br /> FILTERS Treatment can be effective at cleaving CECs into daughter <br /> (3-10 um) chemicars <br /> products,thereby reducing concentrations of <br /> M mbrene specific organic contaminants (Spietel et al, <br /> Concentrate <br /> 1999; Snyder et al 2007). <br /> Membrane Bypass Stream <br /> Figure 3. Typical Membrane Process Comparison of TOC Removal Technologies <br /> The advantages and disadvantages of the <br /> alternative TOC removal technologies are <br /> summarized on Table 1 with other comparative <br /> Advanced Oxidation Processes criteria. <br /> Advanced oxidation processes (AOPs) break s` <br /> down the chemical bonds in organic molecules Chatham, Mass. Case Study and Cost <br /> that make them difficult to be degraded Considerations <br /> biologically. Once these bonds have been i <br /> broken, the organic compound is further Communities throughout Massachusetts are <br /> metabolized by the biological or adsorption exploring alternatives for complying with the <br /> processes. AOPs are often a polishing step to new TOC limitations for groundwater discharge. <br /> destroy particularly recalcitrant organic The Cape Cod and Island communities are z <br /> compounds present in low initial uniquely affected by the new regulations <br /> concentrations, because the Massachusetts Ocean Management i <br /> (Sanctuaries)Act typically does not allow ocean <br /> There are several different AOPs. One common outfalls in this part of the state.All-treated <br /> approach is the use of ultraviolet(UV) light with waters are recharged to the U.S. EPA-designated <br /> a secondary oxidant. Figure 4 presents a basic Sole Source Aquifers of the Cape and Islands, <br /> advanced oxidation process utilizing UV light <br /> and hydrogen peroxide addition. In this The town of Chatham is on the "elbow" of <br /> approach, organic molecules in the treated Cape Cod and is surrounded on three sides by <br /> wastewater are oxidized by hydroxyl radicals, marine estuaries. Over the past 12 years,the <br /> which are formed when UV light comes into town has developed a Comprehensive <br /> contact with a strong oxidant such as peroxide Wastewater Management Plan (CWMP)to <br /> or ozone. Hydroxyl radicals are very strong evaluate.alternatives for enhanced nitrogen <br /> oxidants which attack the chemical bonds of removal (ENR) at its wastewater treatment <br /> the organic molecules.Advanced oxidation facility(WWTF)to address new stringent <br /> typically cleaves organic molecules into smaller nitrogen limits(Stearns &Wheler LLC,2009). <br /> molecules, or daughter products.To reduce As part of this process,the town has evaluated <br /> TOC concentrations, advanced oxidation would alternatives to meet the new TOC regulations. <br /> need to mineralize organic compounds to <br /> 30 The NEWEA Journal Winter 2010 <br />