RESIDUALS MANAGEMENT EXPERIENCE EE&T is considered a national leader in water treatment plant residuals management. Our specialized expertise encompasses all aspects of residuals management including master planning, pilot testing, facility design, beneficial use, disposal, process evaluation, and research. We have completed residuals projects for over 60 water treatment plants ranging in size from 1 to 500 mgd. Master Planning With our expertise, we have developed long range and cost effective residuals management plans for major water utilities across the country, including Philadelphia Water Department (500 mgd), Denver Water Department (275 mgd), Charlotte-Mecklenberg Utility Department (140 mgd), Erie County Water Authority (140 mgd), City of Phoenix (500 mgd), and the West Virginia-American Water Company (75 mgd).    All these studies focused on: Residuals quantification Backwash water treatment and recycle Thickening and dewatering Disposal and beneficial use Pilot testing of residuals treatment technologies often provides useful design and performance data as well as an opportunity for the utility's staff to observe the equipment in operation on their own residuals. EE&T has conducted pilot tests for all types of equipment including centrifuges, belt filter presses, diaphragm filter presses, and gravity belt thickeners. We have in-house capabilities to test sand drying beds, gravity thickening, and dissolved air flotation thickening. Our own laboratory can support residuals pilot tests with such analyses as solids concentration, polymer screening, grain size analysis, shear strength, and specific gravity. Residuals Thickening Residuals thickening is an important aspect for effective nonmechanical and mechanical dewatering. Thickening not only reduces the volume of residuals to be processed, it also enhances the performance of the dewatering equipment. EE&T has experience with evaluating and designing various residuals thickening technologies including: decant tanks, continuous flow gravity thickeners, gravity belt thickeners, centrifuge thickeners, and plate settlers. With numerous installations as a reference point, EE&T can evaluate the performance and economics of various residuals thickening technologies quickly and efficiently. Residuals Pumping EE&T has extensive experience with evaluating and designing reliable pumping systems for WTP residuals. These residuals are thixotrophic in nature and often difficult to pump when thickened and polymer conditioned. Our design group has designed all types of residuals pumps including progressive cavity, rotary lobe, centrifugal, vortex, and plunger. Many of these installations include variable speed capabilities for controlling residuals feed rates to thickeners and dewatering equipment. Our pump stations are designed from an operator's perspective, allowing adequate space for maintenance. Residuals Dewatering Facilities Our residuals treatment design experience includes conventional and high solids centrifuges, belt filter presses, sand drying beds, and gravity thickeners. Some of our designs include cost effective equipment arrangements with screw conveyors and inclined belt conveyors. The residuals dewatering and alum recovery facility for the City of Durham, NC, designed by EE&T, was awarded the National Grand Conceptor Award for Excellence in Engineering in 1994 by the American Consulting Engineer's Council. This facility is the first full-scale alum recovery facility to serve a large water treatment plant (22 mgd). Backwash Water Treatment and Recycle EE&T has been at the forefront in developing treatment strategies for particle count and cysts removal from filter backwash water. Classification and treatment technologies designed by EE&T for backwash water include plate settlers, tube settlers, and conventional gravity clarifiers. All these facilities were further enhanced with equalization basins, variable speed pumping, and polymer treatment. Most designs incorporated flexibility to allow recycle of the backwash water or discharge under a NPDES permit. We have also been at the forefront in testing and developing design criteria for the use of dissolved air flotation for backwash water treatment. Beneficial Use and Disposal We work closely with utilities in developing effective beneficial use/disposal plans for process residuals. Often, this is done before investigating effective treatment strategies. We have been successful in obtaining beneficial use permits for several water utilities which have resulted in significant operational cost savings. EE&T's specific beneficial expertise includes land application, turf farming, top soil blending, co-use with biosolids, and brick manufacturing. Residuals Research EE&T is extremely active in national residuals committees. Our personnel have served on the AWWA Research Foundation Residuals Management Committee for the past 12 years, including several chair positions. In total, EE&T has published and presented over 50 expert papers on residuals management. AWWA Research Foundation documents specifically focusing on water residuals prepared by EE&T and staff include: Handbook of Practice: Water Treatment Plant Waste Management Water Plant Sludge Landfilling Slib, Schlam, Sludge Nonmechanical Dewatering of Water Plant Residuals Impacts of Recycle Streams on Finished Water Characterization of GAC Wastes Treatment Methods for Giardia and Cryptosporidium from Spent Filter Backwash Water Marketing Water Treatment Plant Residuals