Design improvements to the batch demulsification and sorption equipment for pesticide rinsate disposal

Research currently being conducted at Virginia Tech has produced a viable pesticide wastewater clean-up procedure using biologically based materials. The system consists of two steps. First, pesticide laden wastewater is mixed with a lignocellulosic sorbent such as peat moss in a demulsification and sorption step. Second, the wastewater filtered rinsate is then passed through a packed column containing the same sorbent in a column sorption and filtration step. Although the system yielded adequate results and performed the tasks commensurate with its design, the original batch demulsification and sorption phase of the process had several operational problems. Namely, the system was large and not very portable, the recirculation system was not very reliable, and the entire step one process was laborious and time consuming to execute. These problems and limitations prompted the redesign of the step one process into a new, more efficient system. The new system consists of a steel frame similar to the old system. However, the new frame is smaller, lighter, more portable, and one person can easily operate and maneuver the new system. In addition, the new system provides a safer work environment for the operator. The frame surrounds the barrel and liner like a cage so that if the hand winch or the cable fails when lifting the liner out of the barrel, the operator is protected. The recirculation system has been automated such that it 1s self priming, and turns off when all the rinsate contained between the inner liner and outer barrel has been pumped dry. The come-a-long has been replaced with a hand wench that makes loading and unloading of the inner liner easier. Finally, the same pump that is used to recirculate the rinsate is used to transfer the rinsate onto the column for the second sorption and filtration step. There is now no need for additional pumps. After the system was designed and developed, it was tested on two pesticides, atrazine and metolachlor, to determine if the new system yielded results comparable to the old system. The atrazine concentration in the rinsate was reduced from an initial 721 mg/kg (ppm) in step one to 2 mg/kg in the step two column sorption and filtration phase. This represents an atrazine reduction of 99.72% over the entire two step process. The metolachlor concentration in the rinsate was reduced from an initial 704 mg/kg in step one to 30 mg/kg in the step two column sorption and filtration phase. This represents a metolachlor reduction of 95.74% over the entire two step process. The percent reduction of pesticide from the rinsate in the new system is comparable to the 99% reductions obtained using the old system.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Agricultural Engineering

Department dc:contributor.department

Agricultural Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1994

Author dc:creator

• Phillips, Patrick

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-06112009-063429

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/43157