Characteristics and Treatment
Of
Ready-Mix Concrete Waste for Free Discharge
JAMES W. MORROW, Graduate Student
NATHAN C. BURBANK, JR., Professor
School of Public Health
University of Hawaii
Honolulu, Hawaii 96822
EDGAR H. CURTIS, Manager
Plant Engineering Department
H. C. & D., Ltd.
Honolulu, Hawaii 96810
INTRODUCTION
Of the many conveniences in the building industry throughout the world is the
availability of ready-mixed concrete. With a simple phone call one can arrange for delivery
at a specified time of virtually any quantity of ready-mixed concrete of specified quality
(strength, slump, air or water content).
In the United States there are approximately 1900 ready mix concrete manufacturers.
These vary in size from small 4 delivery truck operations to fleet sizes of 50 trucks. Most of
these operations are located near centers of population where concrete construction activity
is centered.
The industry is well aware of its responsibility in quality control, delivery schedules,
and its civic responsibility. Through the National Ready-Mix Concrete Association,
committees are at work on every facet of its Public Relations.
In Hawaii we are fortunate to have one of the largest representatives of the industry in
H.C.and D. Ltd. Ready-Mix Concrete Operations. H.C. and D. Ltd. is a subsidiary of the
Ameron Corporation. The plant, located on approximately 21 acres in the Kalihi Industrial
complex of Honolulu, manufactures and delivers ready mix concrete to one of the most
active construction areas in the United States.
H. C. and D. Ltd. is an integrated operation. Aggregate is quarried, curshed to size,
screened, and brought to the plant. Sand is dredged on a neighbor island, barged to
Honolulu and stored at the plant. Cement is delivered in bulk carrier from a local
manufacturer. Water is secured from the plant's well. Additives are shipped in by ship and
stockpiled for future demand. In the course of a year the plant uses 450,000 tons of
aggregate, 345,000 tons of sand and cinders, and 20.4 million gallons of water, and 500,000
barrels of cement. It produces an annual volume of 565,000 cubic yards of ready-mix
concrete at a maximum rate of 800 cubic yards per hour which is delivered in its fleet of
thirty-five 8 and 12 cubic yard delivery trucks. In addition, the concrete products division
produces many associated concrete products such as structural and architectural blocks
and prestressed concrete members.
This company by virtue of its central city location on Middle Street has as a matter of
management philosophy always been acutely conscious of its civic image and its community
responsibilities. Well before the advent of water quality requirements for receiving waters,
the company had reviewed its operations with a view to minimizing waste discharges.
Further, well before the concept of zero discharge was publicized, the possibilities of
recycling excess water and materials had been investigated.
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