To: Members & Affiliates
From: National Office Date: April 24, 1998 Re: RA 98-8 1996 Sewage Sludge Survey of AMSA Member Agencies
In 1996, AMSA, in cooperation with the Metropolitan Water Reclamation District of Greater Chicago, distributed a sewage sludge (biosolids) survey form to obtain information on biosolids processing characteristics, and the nutrient, metal, and pathogen content of final biosolids products produced by member agency treatment plants. Responses were received from 124 of 152 member agencies in 1996.
There has not been a national survey of biosolids quality in the U.S. since the implementation of 40 CFR Part 503 Sewage Sludge Regulations in 1993. Metal concentrations in the final biosolids products from the AMSA 1996 survey were compared with those of four previous surveys (USEPA 40 City Survey 1979, Mumma 1984, AMSA 1987, and USEPA 1988).
The data received from AMSA member agencies on biosolids characteristics, nutrients (nitrogen, phosphorus, potassium), metals, and pathogens in the final biosolids products from 212 treatment plants were compiled, and summary statistics were prepared on the composition of the final product biosolids types identified in the survey. Final product biosolids types were: liquid, cake, air dried, heat dried, compost, alkaline stabilized, and incinerator ash. The data represented that which they reported to their state, and/or USEPA regional office for regulatory compliance under the Part 503 Sewage Sludge Regulations. An appendix contains the detailed information received from AMSA member agencies.
The survey results point to lower metal concentrations in biosolids and prove the effectiveness of the national pretreatment program and that AMSA members nationwide produce much higher quality biosolids than prescribed by the Part 503 Sewage Sludge Regulations. The mean total solids content of final biosolids products was the lowest in liquid biosolids and the highest in incinerator ash. Incinerator ash also had the highest mean levels of arsenic, cadmium, chromium, copper, molybdenum, nickel and zinc. Of the pathogen comments received on 175 final biosolids products, 40 were reported as meeting Class A requirements and 135 met Class B requirements. As compared with past biosolids surveys from 1979 to 1988, the 1996 AMSA survey shows that there has been a decrease of most metals in final products, with substantial decreases reported for cadmium, copper, lead, mercury, nickel and zinc.
AMSA would like to recognize the hard work of the Research & Development Department of the Metropolitan Water Reclamation District of Greater Chicago, especially Dr. Cecil Lu-Hing, Prakasam Tata, Thomas A. Granato, Richard Sustich, Richard Johnson, and Richard I. Pietz. Copies of this survey report have been distributed to key EPA Office of Water officials.
ATTACHMENT: AMSA Sewage Sludge Survey (Please contact AMSA's National Office at 202/833-AMSA for a copy of this publication)