Introduction

INTRODUCTION

Wastewater treatment is a vital link in the recycling of water resources. The demands on performance and
effluent quality of wastewater treatment facilities have increased substantially in order to comply with higher
standards to protect human health, to clean up rivers and lakes, and to provide needed resources for drinking
water and industrial uses. In addition to the removal of oxygen consuming compounds of carbon and nitrogen,
it has become increasingly important to remove inorganic nutrients such as nitrates and phosphorous.

Most biological wastewater treatment plants use either a fixed film process or an activated sludge process,
each of which have distinctive characteristics. The fixed film process is simpler, and provides more stable
treatment with lower power costs, while activated sludge is more flexible and will meet higher quality effluent
standards.

The Bio-Wheel™ biological treatment system has been developed to combine the compactness and flexibility
of the activated sludge process with the stability and simplicity of the fixed film process. The Bio-Wheel™
system integrates the two processes in a single tank by using a simple mechanical drive system. The rotation
of the Bio-Wheel™ provides alternating air and water cycles for the fixed film process, and aeration and
mixing for the activated sludge process.

With the Bio-Wheel™ system, advanced water treatment with high quality effluent is possible by
biodegradation of the organic compounds, nitrification, and denitrification and uptake of excess P without using
chemicals. The combination of the two processes provides high stability, with low capital and operating costs.