Performance of Internally Clarified
Activated-Sludge Process Treating
Combined Petrochemical-Municipal Waste
G. W. KUMKE, Environmental Engineer
R. A. CONWAY, Group Leader
Research and Development Department
J. P. CREAGH, Waste Treatment Works Manager
Union Carbide Corporation
Chemicals and Plastics
South Charleston, West Virginia
INTRODUCTION
A unique opportunity for long-term evaluation of the performance of an internally clarified activated-sludge unit has been provided at the joint municipal-
industrial wastewater treatment plant in South Charleston, W. Va. Since May
1963, this plant has provided separate primary treatment to a 12 mgd flow from
the South Charleston Plant of Union Carbide Corporation and a two mgd flow from
the City of South Charleston. The initial phase of a step-wise program developed
to control pollution in the receiving Kanawha River required that 28, 000 lbs
BOD 5 be removed daily from the clarified waste in secondary treatment facilities.
During this first phase of the treatment program, considerable operating flexibility existed in achieving this goal under a range of feed conditions.
The key parameters which could be controlled in order to obtain maximum
performance from the 1, 100, 000-gal Aero-Accelator units were feed flow rate,
ratio of domestic to industrial feed, biological solids level, and aeration rate.
These parameters were controlled according to the strength and temperature of
the incoming waste. The purpose of this paper is to analyze the system performance achieved under the various loading conditions. Trie instrumental methods
used to follow performance also should have applicability for others in similar
situations. Improvements made to the facility to achieve additional oxygen
transfer are also to be presented.
The approach of joint treatment of the municipal and industrial wastes was
used for both financial and technical gains. Financing could be achieved through
municipal bonds; minimum rates were possible due to the backing of Union Carbide Corp. The domestic waste provided a continual seed source to the biological units. It also served to cool and buffer the industrial waste, as well as to
dilute any shock loadings. More efficient nutrient utilization was achievable in
combined treatment as the bio-oxidation of the industrial organics served to
scavenge the excess nitrogen and phosphorus from the domestic waste. Joint
treatment also served to reduce costs to the City of South Charleston as the incremental capital and operating costs as part of the large treatment plant were less
than those associated with a separate small plant. The joint Operation also allowed the experience gained in chemical processing operations to be brought to
bear on the treatment of the domestic wastewater.
This initial facility was completed in 1963 at a cost of $5, 800, 000. The
share of Union Carbide Corporation was $4, 900, 000; the cost to the Citv of South
Charleston was $900, 000.    The City of South Charleston financed and built the
-  567  -