24    TREATMENT OF PREWASH DENIM LAUNDRY
WASTEWATERS: CASE HISTORIES
Kevin S. Young, Vice-President
James H. Grant, Project Manager
J. R. Wauford & Company, Consulting Engineers, Inc.
Jackson, Tennessee  38305
INTRODUCTION
Since the mid-1980s the prewashed denim segment of the textile laundering industry has had a
significant impact on water quality in Tennessee and other states. Lack of understanding by laundry
operators of the characteristics and variability of prewashed denim laundry wastewater, coupled with
the large volume of discharge from prewashed denim laundries, has led to several instances of severe
upset at municipal wastewater treatment plants. Reported upsets range from inhibition of disinfection
capabilities due to high chlorine demand to killing biological treatment processes. These problems
have created an attitude among some water quality regulators that prewashed denim laundry wastewaters cannot be successfully managed. This attitude has been exacerbated by the unsuccessful
attempts of certain chemical suppliers, equipment manufacturers, and consulting engineers, to provide wastewater management programs to the prewashed denim industry without a thorough understanding of prewashed denim wastewater characteristics.
Methodologies for treatment of prewashed denim laundry wastespace waters utilizing existing
proven technologies have been previously reported.1,2 The purpose of this paper is to present design
parameters, operational results and actual costs in the form of case histories for two successful
prewashed denim laundry wastewater management programs.
H.I.S. COMPANY INC/TOWN OF BRUCETON, TENNESSEE
Shortly after beginning construction of a two cell facultative lagoon system to treat municipal
wastewater in 1988, the Town of Bruceton, Tennessee was informed of the intention of H.I.S.
Company, Inc. to construct a prewashed denim laundry at its sewing facility in Bruceton. In order to
accommodate the 100 jobs the proposed laundry offered, a study was undertaken to determine if
design modifications to the lagoon facility under construction were feasible to allow acceptance of the
prewashed denim laundry wastewater. The study indicated that pretreatment by H.I.S. Company,
Inc. consisting of pH adjustment, fine screening and sedimentation for suspended solids removal, and
combined treatment of the laundry and municipal wastewater streams for biochemical oxygen
demand (BOD5) and color removal were feasible and offered the most cost effective wastewater
management alternative. The lagoon facility under construction could be modified to a two cell,
partially mixed, aerated lagoon followed by a single cell facultative lagoon.
Bruceton received a Tennessee Industrial Infrastructure Program grant from the Tennessee Department of Economic and Community Development for the modifications to the lagoon facilities under
construction to accommodate the prewashed denim laundry wastewater. The "as-constructed" process
train for pretreatment and combined treatment is depicted in Figure 1.
Pretreatment System
The H.I.S. Company, Inc. pretreatment system is designed for a flow of 450 gpm and consists of
two 60-inch diameter, 60 mesh shaker screens manufactured by Kason Corporation, an automatically
controlled pH adjustment system for feeding 50% liquid caustic (NaOH), and an inclined plate settler
manufactured by EIMCO Process Equipment Company, having a plate area of 1170 ft2. The inclined
plate settler is designed to produce an effluent total suspended solids (TSS) concentration of less than
600 mg/L at a rise rate of 0.38 gpm/ft2 without polymer addition.
46th Purdue Industrial Waste Conference Proceedings, 1992 Lewis Publishers, Inc., Chelsea, Michigan 48118.
Printed in U.S.A.
235