US 12,351,482 B2
Method for the treatment of wastewater
Gerard Willem Smiddy, Grand Rapids, MI (US); and Frank Leslie Smiddy, Thompsonville, MI (US)
Assigned to Evoqua Water Technologies LLC, Pittsburgh, PA (US)
Filed by Evoqua Water Technologies LLC, Pittsburgh, PA (US)
Filed on Nov. 17, 2021, as Appl. No. 17/528,515.
Application 16/299,691 is a division of application No. 16/231,861, filed on Dec. 24, 2018, granted, now 11,192,803, issued on Dec. 7, 2021.
Application 14/983,831 is a division of application No. 13/947,883, filed on Jul. 22, 2013, granted, now 9,255,025, issued on Feb. 9, 2016.
Application 17/528,515 is a continuation of application No. 16/299,691, filed on Mar. 12, 2019, granted, now 11,198,625.
Application 16/231,861 is a continuation of application No. 14/983,831, filed on Dec. 30, 2015, granted, now 10,160,664, issued on Dec. 25, 2018.
Claims priority of provisional application 61/674,040, filed on Jul. 20, 2012.
Prior Publication US 2022/0073375 A1, Mar. 10, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. C02F 1/28 (2023.01); C02F 1/00 (2023.01); C02F 1/38 (2023.01); C02F 1/52 (2023.01); C02F 9/00 (2023.01); C02F 9/20 (2023.01); C02F 1/74 (2023.01); C02F 101/20 (2006.01); C02F 101/32 (2006.01); C02F 103/10 (2006.01)
CPC C02F 1/281 (2013.01) [C02F 1/004 (2013.01); C02F 1/38 (2013.01); C02F 1/52 (2013.01); C02F 9/00 (2013.01); C02F 9/20 (2023.01); C02F 2001/007 (2013.01); C02F 1/283 (2013.01); C02F 1/288 (2013.01); C02F 1/74 (2013.01); C02F 2101/203 (2013.01); C02F 2101/32 (2013.01); C02F 2103/10 (2013.01); C02F 2201/008 (2013.01); C02F 2209/00 (2013.01); C02F 2209/40 (2013.01); C02F 2303/16 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A method of backwashing a sand filter in a wastewater treatment system, the method comprising:
a) flowing wastewater through at least one sand filter in a first flow direction;
b) backwashing the at least one sand filter to form backwashed water;
c) upon initiation of step b), automatically injecting chlorine into the at least one sand filter;
d) flowing the backwashed water from the at least one sand filter to at least one hydrocyclone to separate the backwashed water into solid material and liquid;
e) flowing the solid material from the at least one hydrocyclone into a slop tank for temporary storage of the solid material;
f) flowing the liquid from the at least one hydrocyclone into a settling tank; and
g) flowing the liquid from the settling tank and into a holding tank.