Section Seven
BIOLOGICAL PROCESSES
28    BIODEGRADATION OF A MEDIUM-STRENGTH
MACHINING WASTEWATER USING A MEMBRANE
BIOLOGICAL REACTOR
Arthur H. Kuljian. Jr., Senior Project Manager
McNamee Industrial Services, Inc.
Ann Arbor, Michigan 48108
John R. Porter, Project Engineer
Theping Chen, Site Engineer
McNamee, Porter & Seeley, Inc.
Ann Arbor, Michigan 48108
INTRODUCTION
In 1993, a Midwestern refrigeration compressor manufacturer determined that its existing
physical-chemical wastewater treatment system would be unable to consistently comply with the
regulatory effluent limitations of its future city discharge permit renewal. Furthermore, the federal Environmental Protection Agency's proposed Metal Products and Machinery (MP&M) Pretreatment Standards coupled with the facility's ability to handle future manufacturing plant flows
had made it evident that upgrading the existing treatment system would be required. This chapter
describes the investigations and results from treatability studies undertaken by McNamee Industrial Services, Inc., in determining the optimal treatment and design criteria for a full-scale treatment system.
BACKGROUND
The compressor company's process sewer transports mainly contact cooling waters from the facility's machining operations, which are treated in a 20,000 gallon/day wastewater treatment facility prior to discharge to the local Publicly Owned Treatment Works (POTW). Major constituents
from the machining, welding and soldering, rinsing and painting, and housekeeping operations include: acid and alkali cleaning compounds, maintenance cleaners, metal preparation solutions, oil
demulsifiers, and rinse waters. A process flow diagram of the existing wastewater treatment process
is shown in Figure 1. Primarily, the parameters of concern for meeting the POTW's proposed local
limits are 5-day biochemical oxygen demand (BOD5), total Freon-extractable oil and grease
(TFOG), total petroleum hydrocarbons (TPH), and metals (lead, nickel and zinc).
In early 1994, McNamee performed bench-scale testing of four viable treatment processes to
achieve the proposed effluent limitations and to allow for the future reuse of treated wastewater.
The processes evaluated were carbon absorption, alternate chemical treatment (a polymer conditioning system), ultrafiltration, and a membrane biological reactor (MBR). The results indicated
promising performance by the MBR process at relatively high organic loading conditions, as
well as a reasonable capacity to handle variant loads. The carbon absorption, polymer conditioning and ultrafiltration systems were all able to effectively reduce oil and grease concentrations to
both the permit level and for certain water reuse applications; however, removals of refractory
organics (synthetic oils and greases) exhibited poor performance. Figure 2 depicts the relative removals of the critical parameters by each alternate. It was concluded from this study that the
MBR provided more cost-effective treatment at steady-state than the other treatment processes.
51st Purdue Industrial Waste Conference Proceedings, 1996, Ann Arbor Press, Inc., Chelsea. Michigan 48118.
Printed in U.S.A.
257