AWWA ACE94281

This paper reviews methods of filtration implemented to date at small New Hampshire water systems which draw from surface sources and provides a profile of costs incurred in addressing this issue. Slow sand filtration and package conventional filtration are the methods chosen at a majority of small New Hampshire systems to date. A review of construction and operation and maintenance costs lends perspective in making future technical choices at other water systems. The examination of filtration plants currently operating at small water systems plus analysis of costs for both existing and proposed plants has illustrated costs which could be incurred at other small water systems under similar operating conditions. Filtration methods implemented at small New Hampshire water systems meet the performance standards of the Surface Water Treatment Rule with a level of complexity appropriate to the site-specific conditions. Costs for each filtration method examined cover a wide range and appear to vary significantly with plant size and site-specific conditions. The costs examined here indicate that slow sand filtration or pressure ceramic filtration generally offer lower construction and operating costs than package conventional filtration in plants of 1.0 mgd capacity and less.