Water and wastewater systems have been estimated to account for 4% of total electricity demand
in the US. The demand for water from a growing population is rapidly outstripping the supply
available from the highest quality water sources, so agencies are turning to lower quality sources
of supply. To treat these waters and at the same time meet increasingly stringent drinking water
regulations, agencies are implementing sophisticated advanced treatment technologies (ATT),
such as ozonation and UV, methods that require more and more electrical energy. The energy
consumption issue is further aggravated by the ever-increasing energy cost. While the cost of
treatment equipment has been decreasing due to advancements in technology, the cost of energy
could be escalating. For example, due to the significant decrease in membrane costs during the
last 20 years, energy consumption is now the second largest fraction of unit water cost (capital
recovery represents the largest fraction) for seawater reverse osmosis (RO) desalination. For one
of the most recently constructed plants, at Point Lisas, Trinidad, energy represents 23% of the
total water cost. This AwwaRF funded project surveys 11 participating utilities that utilize
various types of ATT. Energy consumed by UV process is found to be merely 0.001 kWh/kgal,
and ozonation process consumes 0.05-0.12 kWh/kgal of energy. This study also concludes that
energy efficiency is greatly affected by the ratio of operation capacity to design capacity. Energy
efficiency is much higher (lower energy consumption per unit of water produced) when the
system is operated at or close to the design capacity. When the system is operated at lower
production such as during winter time, energy efficiency decreases sharply. Includes 14 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 340 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 30 |
| Published : | 11/01/2007 |
