Effect of Boron on Aerobic Biological
Waste Treatment
SHANKHA K. BANERJI,   Assistant Professor
BRIAN D.  BRACKEN, Graduate Student
B. M. GARG, Graduate Student
Department of Civil Engineering
University of Delaware
Newark, Delaware
INTRODUCTION
In June 1965, the detergent manufacturers of this country voluntarily switched
from a biologically resistant to a biologically degradable surface active agent in
the packaged household and industrial detergents (1). This change has materially
reduced the hazards of water pollution attributed to detergents in the form of
foaming of waterways and sewage plants, poor oxygen transfer, toxicity to aquatic
life, tastes imparted to the water, etc. This was probably a unique instance of
industry's willingness to voluntarily spend millions of dollars to develop new technology and materials in response to the public sentiment concerning water pollution, without any federal or legal intervention as in other countries. However, it
appears that detergents may be blamed once more for a water pollution situation
created by the increased use of borates, perborates and other boron salts which
may be as high as eight to 17 per cent of the total weight of the packaged deter-
fents (2,3). These boron salts used in the detergent act as, cleansing agent,
uilder compounds, sanitizers, and corrosion inhibitors (4). The result of this increased use of boron salts in detergents is the increase of boron level in the wastewaters and receiving waters (5).
Beside its use in detergent manufacture, boric acid and boron salts are extensively used in industry for weather-proofing wood, fire-proofing fabrics, manufacture of glass and porcelain, production of leather and carpets, cosmetics,
photography, artificial gems, and many other purposes (6). Boron hydrides (bo-
ranes) are used as rocket fuel and may be encountered in other situations where
high energy fuels are desired. Wastes produced from some of these industries
would also contribute to the increase of the boron level in the waste receiving
water bodies.
The increased levels of boron salt in wastewaters may have several effects on
the environment. Firstly, high boron levels may be harmful to the operation of
the biological waste treatment systems (Activated sludge process, trickling filtration, anaerobic sludge digestion and waste stabilization ponds). Secondly, such
wastes discharged into receiving water bodies may be harmful to the aquatic life-
fish, water plants, algae and microorganisms. Lastly, the water in the receiving
stream if used for irrigation and water supply might be hazardous to plants and
human beings.
LITERATURE REVIEW
Boron is usually a nonessential element for most microorganisms (7, 8) although
- 956 -