Remtech recently demonstrated its emergency pre-treatment facility deployment capabilities for a major food manufacturing facility when their plant began to fail with leaking tanks and non-functional pumps and a DAF system. The temporary treatment system was designed to operate for four months while the new plant was being designed and constructed.
Six (6) 20,000 gal frac tanks were mobilized to provide unit operations for the plant. Raw wastewater was diverted to a primary 20,000 blending tank following an existing rotating screen. An equalization basin was constructed of three (3) frac tanks connected in parallel where the flow was spit equally between the three tanks providing a five hour retention time for flow and concentration equalization.
Mixing was provided in each tank by constructing a fine bubble (50 micron) diffusion system assembled outside each tank that was anchored in each tank by eight (8) 85 pound magnets. Pre-assembled air diffuser heads and feed lines were inserted through a 30" manhole with only 5 universal fittings requiring tightening inside each frac tank. Sixteen (16) diffusers in each tank provided concentration equalization and enough mixing to prevent settling of solids. An existing 5 Hp rotary lobe blower (187 cfm @ 15 psi) provided air that was balanced between the three tanks to provide uniform mixing and oxygen for biological oxidization. Air mixing pilot tests on Remtech’s four diffuser heads on 34” centers required 1.3 cfm air per head at 5 psi to produce a radius of influence of 8 ft. Available air provided three times the air required for mixing and oxidization.
Wastewater from the equalization basin flowed through a seven (7) tier 10 ft long serpentine chemical floculation/mixing system constructed out of four-inch schedule 80 PVC that provided a 15 second mixing time between acid/base/alum addition and a PID pH controller. A new 20 micron bubble pump was installed to restore the operation of the dissolved air floatation system. This pump eliminated the need for a compressor, pressure vessel, ejector, and static mixer.
The plant was constructed in phases that allowed the plant to continue to operate and was completed in 15 days.