Department of Public Works
Redevelopment active link
 Seawater Barriers
Well Redevelopment

The redevelopment of a well is the removal of fine material, organic or inorganic, from the well casing, perforations, gravel pack and surrounding aquifer. The process cleans out and opens up or enlarges the passages so that water may enter the well more freely. A well is first developed when originally constructed, but eventual clogging makes subsequent redevelopment necessary. One reason for clogging is the combination of a buildup of materials brought in by the injection water and the simultaneous or subsequent chemical changes in these particles. Another reason for clogging is bacterial growth. In these cases the well is treated chemically and the dead organisms removed along with the fine particles.

Wastewater which is brought to the surface is processed through a mobile water treatment facility. The system removes the suspended solids found within the effluent, plus adjusts the Ph and turbidity prior to discharge into nearby storm drains.

drawing of treatment facility
Click on drawing to enlarge

The air-lifted wastewater enters the primary treatment system with intermittent high-energy flows through an inlet pipe (A). Between this point and the inlet energy dissipater (C), chemical additives are injected into the inlet pipe by an air driven metering pump (B). The chemical storage tanks (D) are required with an air driven agitator (E), which mixes one of several stock chemical prior to injections.

The functions of the primary tank are energy dissipation, flash mixing, primary coagulation of flocculent particles, and sedimentation. Quantities of wastewater, silty sands, and compressed air enter the central downcomer (P). The compressed air is separated from the flow of water and is vented through the roof downcomer. At this point, the velocity of the wastewater has been reduced as it is forced to travel through the downcomer. Flash mixing of wastewater and chemical additives is completed by the violent turbulence inside the downcomer as the wastewater moves down into the outer chamber of the tank. The air manifold (F) continues to aerate the treated wastewater to form large flocculated particles. The heavier sand, silts, and flocculated particles settle to the bottom of the primary tank, as the upward velocity (1 fpm) is not adequate to carry the unwanted upward. The wastewater is collected off the top of the tank by the slotted discharge collector manifold (G). The manifold is designed to minimize "short circuiting" of wastewater through the tank, inducing near uniform discharge over the top cross section of the tank. The collected water is discharged through two outlet pipes, which further reduces the velocity of the wastewater. The wastewater from the primary tank is transferred to the rectangular fiberglass clarifier through two pipes (H). The incoming treated wastewater is uniformly distributed to the baffled flocculation chamber (J) by the inflow distribution chamber (I). Agglomeration of small light floc occurs as the wastewater moves down through the baffled flocculation chamber and into the sedimentation chamber at the bottom of the tank (K). As the wastewater moves through the sedimentation zone (L) and through the 60-degree tube settlers, all remaining flocculated settable solids are trapped on the inclined surfaces to settle to the bottom of the tank. The clear water at the top of the tube settlers is collected uniformly off the surface of the sedimentation chamber by three PVC discharge collector pipes (M). These pipes flow to the external discharge collector channel (N). The disposing of this treated wastewater through a flow meter (O) provides documentation of the quantities of water discharged through the treatment facility. Discharged water after reasonable treatment should meet the standards imposed by the Regional Water Quality Control Board as conditions to meet NPDES permit requirements.
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