Treatment of potato farm wastewater with coagulation

Citation

Bosak, V.K., VanderZaag, A.C., Crolla, A., Kinsley, C., Miller, S.S., Chabot, D., Gordon, R.J. (2017). Treatment of potato farm wastewater with coagulation. Applied Engineering in Agriculture, [online] 33(1), 95-101. http://dx.doi.org/10.13031/aea.11609

Plain language summary

Wastewater from on-farm potato storage facilities contains suspended particles that require treatment for removal. Sedimentation is a treatment used but it does not sufficiently remove these particles. This study investigates using coagulation as a potential method for reducing these suspended particles. Four different coagulants were used in this study: alum, FeCl3, and the other two being polymer coagulants. Cost is the most important factor with coagulation for farmers but convenience and effects on wastewater must also be considered. Lower costs were found with an Alum coagulant but higher volumes were also required (less convenient). As well, the pH was changed to become more acidic for both alum and FeCl3 coagulants. Thus, more chemical additions are required to return the water to neutral pHs. Polymer coagulants were found to be more convenient requiring less volume and not altering water pH.

Abstract

The processing wastewater from an on-farm potato storage facility contains substantial concentrations of colloidal particles that are hard to remove through sedimentation alone. This study evaluated coagulation as a potential approach for reducing total suspended solid levels. Wastewater was coagulated with two proprietary Nalco polymers, as well as aluminum sulfate (alum) and ferric chloride (FeCl3). One of the Nalco polymers required the smallest volume to achieve 50%, 75%, or 90% total suspended solids removal. However, alum was consistently the least expensive product, despite the larger volume required. Although cost is an important factor for farmers, the convenience of using a smaller volume and the effects of coagulation on pH are also important factors to consider. Both polymers had minimal effect on pH, whereas alum and FeCl3 resulted in a pH below 6 at high concentrations. In consequence, alum and FeCl3 require additional chemicals to maintain a biologically neutral pH, thus also requiring extra work and expense. Future research should focus on on-farm coagulant trials to verify laboratory results and optimize protocols for on-farm use.

Publication date

2017-01-01

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