| water treatment (WWT) uses many different | | | | decimation of the microorganism population, and |
| processes to achieve the ultimate goal of discharging | | | | ultimately in non-compliance. |
| wastewater that meets all applicable regulations. | | | | It takes experience and expertise to operate an |
| Recently some significant improvements in WWT | | | | activated sludge facility in the event of upset |
| have been cropping up in the Food and Beverage | | | | conditions. Another issue with most traditional |
| industry since the composition of this industry's | | | | activated sludge processes is the large footprint and |
| wastewater streams can be very complex, and | | | | the associated high initial capital costs. |
| highly variable, making the treatment of wastewater | | | | As a result of these issues with the activated sludge |
| quite challenging, especially in the Secondary WWT | | | | process, newer technologies have been developed |
| phase. | | | | over the past few years. The Membrane Bioreactor |
| The demands made on the food and beverage | | | | (MBR) and the Sequencing Batch Reactor (SBR) |
| industry are numerous and range from health and | | | | processes are two such technologies. |
| financial issues to environmental concerns. | | | | The use of MBR and SBR has become widespread in |
| Two additional factors are adding to this challenge. | | | | the Food and Beverage industry, due to the typical |
| First, environmental discharge regulations continue to | | | | wastewater composition, a general tightening of |
| tighten, making it difficult for some facilities to | | | | discharge regulations, and water shortages. MBR and |
| consistently operate without NPDES violations. | | | | SBR treated wastewater is much better suited for |
| Second, climate change, drought conditions and the | | | | reuse or recycle than activated sludge treated |
| trend towards water conservation are forcing some | | | | effluent. |
| WWT facilities to recycle a portion of their water for | | | | Membrane Bioreactors |
| in-plant use. The end-use of this recycled water may | | | | The MBR process combines activated sludge |
| dictate an even higher quality standard than what is | | | | treatment with a membrane for liquid-solid separation. |
| required for discharge. | | | | While MBR can achieve almost complete separation |
| Wastewater treatment can be divided into five | | | | of suspended solids and dramatic reduction in |
| processes: pre-treatment, primary, secondary, and | | | | contaminants, it is prone to membrane fouling. |
| tertiary treatment then finally disinfection. | | | | Fortunately, the recent advent of PTFE membranes |
| Secondary WWT is arguably the most important of | | | | and improved system designs have minimized the |
| the processes used in the treatment of waste in the | | | | need for membrane maintenance to prevent fouling. |
| Food & Beverage industry, due to the high and | | | | Sequencing Batch Reactor |
| varying levels of soluble and suspended organic | | | | A SBR process typically consists of at least two |
| matter in the wastewater. Unfortunately, it is also | | | | identically equipped reactors with a common inlet, |
| arguably the most complex of the WWT processes, | | | | valved to direct flow to one reactor or the other. As |
| and can therefore create many challenges from an | | | | the name implies, the reactors work as batch |
| operations perspective. | | | | operations and by nature are easier to operate than |
| The Activated Sludge Process | | | | continuous flow systems since every batch can be |
| The first major development in Secondary WWT | | | | treated and controlled separately. In addition, SBR |
| was the introduction of the activated sludge process | | | | systems often have a smaller footprint and capital |
| in England in 1913. The activated sludge process | | | | cost and are easier to operate than other types of |
| combines sewage, a concentrated mass of microbes, | | | | systems. On the downside, SBR may be limited to |
| and high levels of dissolved oxygen to promote the | | | | smaller wastewater flows. |
| consumption of organic content. | | | | An in-depth discussion of sewage treatment |
| The activated sludge process is still very widely used, | | | | equipment and package wastewater equipment for |
| and has evolved into many different variations, | | | | the Food and Beverage Industry as well as other |
| depending upon specific waste treatment | | | | industrial applications including performance tables and |
| requirements. | | | | drawings can be downloaded in the free 10 page |
| The activated sludge process can be quite daunting | | | | Layne Christensen white paper titled "The Evolution |
| to operate properly. Loss of control by WWT plant | | | | of Secondary Wastewater Treatment in the Food |
| operators, can result in loss of the activated sludge, | | | | and Beverage Industry" (A $97 Value). |