Understanding the Cost Factors of Wastewater Treatment & Disposal

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COLLECTION COSTS To estimate the cost of collection, data on the costs for gravity pipes, pressure pipes, grinder pumps, and pumping stations of various sizes were analyzed. It was assumed that 5% of the properties would require grinder pumps and that one pump station would be necessary for every 100 properties. For more details, see Figure 5 in the Barnstable County Cost Report, which illustrates the relationship between density (distance between properties) and the cost of a collection system, shows that cost vary directly with density of development. COSTS PER POUND OF NITROGEN REMOVED AND SENSITIVITY ANALYSIS Based on a set of underlying assumptions (e.g., land costs, wastewater flows, transport distances, and disposal location, among others), costs were estimated for 14 hypothetical scenarios of different-sized systems. Capital costs for collection, transport, treatment, and disposal and O&M costs were calculated as was the equivalent annual cost (amortized capital cost plus O&M). Based on the efficacy of nitrogen removal of the different kinds of systems, an equivalent annual cost per pound of nitrogen removed was calculated. As shown in Table UCF-2, individual denitrifying systems have the lowest capital costs, primarily because they do not require a collection system. Centralized systems and large satellite systems have the lowest O&M costs. Combining both capital and O&M costs into an equivalent annual cost per property, centralized systems are the least expensive, especially when nitrogen-removal capability is factored into the calculation. A sensitivity analysis was then undertaken in which the underlying assumptions were changed for each of the 14 scenarios. As noted above, a very significant cost driver for wastewater infrastructure other than onsite systems is the cost of collection. Therefore the sensitivity analysis held collection costs constant across all scenarios. 6 UNDERSTANDING COST FACTORS | REGIONAL WASTEWATER MANAGEMENT PLAN
TABLE UCF-2: Cost per Pound of Nitrogen Removed Using Different Kinds of Wastewater Treatment TYPE OF TREATMENT Individual Systems CAPITAL COST ESTIMATED COST PER PROPERTY SERVED ANNUAL O&M EQUIVALENT ANNUAL COST EQUIVALENT ANNUAL COST* PER POUND OF NITROGEN REMOVED DOLLARS ($) PER POUND OF NITROGEN PERCENT (%) PREMIUM OVER 3.0 MILLION GALLONS- PER-DAY (MGD) CENTRALIZED SYSTEM Title 5 $13,000 $110 $1,150 Not applicable Not applicable Nitrogen-removing: Current Practice Nitrogen-removing: Enhanced Current Practice Nitrogen-removing: For TMDL Compliance Cluster Systems $24,000 $1,250 $3,180 $820 187% $26,000 $2,000 $4,090 $580 102% $28,000 $3,200 $5,450 $770 169% Current Practice $48,300 $1,050 $4,920 $820 186% For TMDL Compliance $52,000 $2,800 $6,940 $710 149% Satellite Systems 50,000 gpd $55,100 $1,670 $6,080 $680 138% 100,000 gpd $51,300 $1,360 $5,480 $590 109% 200,000 gpd $47,700 $1,030 $4,860 $510 79% 300,000 gpd $46,300 $860 $4,570 $470 64% Centralized Systems 1.5 mgd $42,900 $500 $3,940 $305 7% 3.0 mgd $40,900 $400 $3,680 $285 —— *NOTES: Equivalent annual costs are based on 5%, 20-year financing. Watershed-wide costs must consider the number of properties served and the average cost per property. SOURCE: Barnstable County Wastewater Cost Task Force, “Comparison of Costs for Wastewater Management Systems Applicable to Cape Cod,” April 2010. REGIONAL WASTEWATER MANAGEMENT PLAN | UNDERSTANDING COST FACTORS 7
Page 1: CAPE COD Regional Wastewater Manage
Page 5 and 6: Introduction In most areas of the U
Page 7 and 8: Cost Comparison of On-Site, Cluster
Page 9: COMPARATIVE COSTS OF CLUSTER, SATEL
Page 13 and 14: Guidance on Selecting Different-siz
Page 15 and 16: Non-cost factors should also be con
Page 17 and 18: CONDITIONS LEAST FAVORABLE Centrali

Understanding the Cost Factors of Wastewater Treatment & Disposal

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