Date of Defense
Date of Graduation
Chemical and Paper Engineering
The total maximum daily limit (TMDL) of phosphorous permitted to be discharged into the Kalamazoo River Watershed by point sources will need to be lowered in the future. Research was done to determine the methods available to remove phosphorous from wastewater and how they could be implemented for Otsego Paper, Inc. Several methods are used currently by municipalities including chemical, biological, and physical methods. We researched their effectiveness, and costs if implemented. The completed comparison can be used to aid in future company decisions as well as provides comprehensive information on these removal processes.
Biological phosphorus removal is commonly used for municipalities however there is limited information on how effective it will be for a paper mill. There are distinct differences in the type of wastewater that may cause efficiency to decrease. A membrane bioreactor may be more compatible with Otsego Paper, Inc however a lot of design work would be needed. We recommend seeking design and pilot testing work from the listed resources in the report.
Chemical addition is the most commonly used method of phosphorus removal. Metal salts react with ortho-phosphate to form precipitates which will then settle out. These metal salts are also coagulants and help with the settling of Total Suspended Solids (TSS). The combined effect of removing ortho-phosphate and additional TSS can reduce total phosphorus by 29%. The process creates additional sludge however the current sludge press at Otsego Paper, Inc. has more than enough capacity and can handle the sludge with no additional cost. This process is the least expensive to install and operate.
Physical methods investigated include granular filtration, surface filtration, microfiltration, and reverse osmosis. The only feasible of these methods are the granular and surface filtration. Described in the report are sand and disk filters capable of removing 90% of TSS which correlates to a 78% reduction in total phosphorus. These filters also have continuous backwashing capabilities which decrease downtime for maintenance.
Based on our calculations and information, we recommend using a combined chemical and surface filtration treatment. This option removes 87% of the total phosphorus and is cost efficient. Both of these treatments can be easily installed at Otsego Paper, Inc. and would require no addition labor. Also, further steps should be taken to test the effectiveness, such as pilot testing. Venders listed should also be contacted for further design work.
Kaiser, Megan, "Phosphorous Removal Process Comparison" (2013). Honors Theses. 2247.