TREATMENT OF HIGH STRENGTH
WASTEWATER CONTAINING ORGANIC SOLVENTS
Kurt R. Marston, Chief Engineer
Franklin E. Woodard, President
Woodard and Curran, Inc.
Gorham, Maine 04038
INTRODUCTION
The Millipore Corporation manufactures and markets precision separations systems for the pharmaceutical, microelectronics, health care and other industries. Some of the membranes used in their
products are manufactured at Millipore's Bedford, MA facility. The company corporate offices and
research and development facilities are also located in Bedford. The manufacturing activities result
in the production of over 100,000 gallons per day of wastewater containing traces of glycerin, alcohol,
acetone and other organic chemicals. This wastewater is discharged to the municipal sewer which is
connected to the Metropolitan District Commission (MDC) sewer system serving the Metropolitan
Boston area.
Shortly after the implementation of their Industrial Pretreatment Regulations, the MDC notified
the Millipore Corporation of their intention to place limitations on the discharge of solvents from
the Bedford plant. Based upon the limits proposed by MDC, Millipore would be required to reduce
the mass emission of six chemicals by approximately 50% of current levels. At the same time Millipore
was projecting increases in production and the addition of new product lines at Bedford which would
increase the required reductions.
The Millipore Corporation investigated alternatives for complying with MDC discharge requirements including in-plant modifications to eliminate or reduce waste streams, solvent recovery and/or
reuse, waste stream segregation and treatment methods. Investigation of treatment methods included
pilot testing of activated sludge. Based upon a number of factors, including removal efficiency, implementation time, flexibility and cost, a program of segregation of high strength waste streams for
pretreatment using the activated sludge process was implemented.
The purpose of this paper is to discuss the design and operation of the activated sludge system
at the Millipore Corporation plant in Bedford, MA.
PILOT PLANT
In November and December, 1980 a laboratory bench scale study was performed to determine
the feasibility of pretreating high strength wastewater using the activated sludge process and to determine the biokinetic coefficients for design of the full scale treatment system.
The pilot plant consisted of five continuous-flow, bench reactors (similar to the sketch in Figure
1) fed from a common reservoir. The reactors were started up using activated sludge from a municipal
treatment plant and a dextrose-based feed. Once the reactors were brought to a steady state on the
dextrose solution (approximately 30-days from start), Millipore wastewater was added to the dextrose
mix. Its percentage was gradually increased until the reactors were receiving 100% Millipore waste
(approximately 60 days from start) plus nitrogen and phosphorus supplements. The wastewater used
for the pilot test was synthesized using chemicals supplied by Millipore and mixed in proportions
and concentrations predicted to occur from waste stream segregation and projected production
changes. The composition of the experimental wastewater is presented in Table I. The total oxygen
demand of the experimental wastewater was calculated to be 9642 mg/1. The BOD, measured using
an acclimated seed was 3200 mg/1.
735