Technologies and Costs for Removal of Arsenic From Drinking Water
Technologies and Costs for Removal of Arsenic From Drinking Water
Technologies and Costs for Removal of Arsenic From Drinking Water
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4.0 RESIDUALS HANDLING AND DISPOSAL ALTERNATIVES4.1 INTRODUCTIONThe implementation <strong>of</strong> any <strong>of</strong> the treatment technologies presented in Chapter 3 will result inthe generation <strong>of</strong> solid <strong>and</strong>/or liquid waste streams containing elevated levels <strong>of</strong> arsenic. It is thepurpose <strong>of</strong> this chapter to present the characteristics <strong>of</strong> the residuals generated by each <strong>of</strong> the treatmenttechnologies <strong>and</strong> to discuss appropriate h<strong>and</strong>ling <strong>and</strong> disposal options.4.1.1 Factors Affecting Residuals H<strong>and</strong>ling <strong>and</strong> Disposal <strong>Costs</strong>There are a number <strong>of</strong> factors which can influence residuals h<strong>and</strong>ling <strong>and</strong> disposal costs. Thisdiscussion is concerned with those factors affecting capital cost, as well as factors affectingoperations <strong>and</strong> maintenance (O&M) costs. Capital costs include equipment, construction, installation,contractor overhead <strong>and</strong> pr<strong>of</strong>it, administrative <strong>and</strong> legal fees, l<strong>and</strong>, <strong>and</strong> other miscellaneous costs.The primary factor affecting capital cost is the quantity <strong>of</strong> residuals produced, which is dependent onthe design capacity <strong>of</strong> the water treatment plant <strong>and</strong> the treatment process utilized (e.g.,coagulation/filtration vs. lime s<strong>of</strong>tening).The amount <strong>of</strong> waste generated by a treatment process plays a significant role in determiningthe h<strong>and</strong>ling <strong>and</strong> disposal method that will be utilized. For example, many h<strong>and</strong>ling methods whichare suitable <strong>for</strong> smaller systems are impractical <strong>for</strong> larger systems because <strong>of</strong> significant l<strong>and</strong>requirements associated with particular methods. As a result, larger systems that process residualson-site (as opposed to direct or indirect discharge) typically use mechanical methods to avoid largeoutlays <strong>for</strong> l<strong>and</strong> purchase, preparation, <strong>and</strong> maintenance.Operations <strong>and</strong> maintenance costs include labor, transportation, process materials <strong>and</strong>chemicals, <strong>and</strong> maintenance. Many h<strong>and</strong>ling <strong>and</strong> disposal methods require extensive oversight whichcan be a burden on small water systems. Generally, labor intensive technologies are more suitable<strong>for</strong> large water systems. Transportation also can play a significant role in determining appropriateh<strong>and</strong>ling <strong>and</strong> disposal options. If <strong>of</strong>f-site disposal requires extensive transportation, alternativedisposal methods should be evaluated. Complex h<strong>and</strong>ling <strong>and</strong> disposal methods usually requiregreater maintenance than less complex methods.4-1
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