Organizations use a combination of three types of control systems to ensure their operations run smoothly. An inflow flow division filter system has an adjustable landfill placed at the inlet of each filter cell. The affluent landfill is the main component of the system, and a feed pipe or channel common to all filter cells carries water to the individual landfills. The inlet dumps are adjustable so that each one can be placed at the same height to obtain a uniform division of the flow.
Auxiliary equipment often includes an affluent control valve and a hydraulic effluent control point to maintain a minimum water level in a filter cell. The affluent control valve is used to stop the incoming flow if it is necessary to remove the cell from service, for example, during a backwash case. The hydraulic control point for the effluent can consist of a downstream landfill or an inverted circuit in the effluent pipe. Constant level control is similar to effluent flow control, since the detection system compares current conditions with the desired set points and works together with the control valve to align the two conditions.
In a constant level control system, the level sensing device determines the actual water level and compares it with the set point. The comparison method depends on the sensing device, the control valve actuator, and the communication controller. Decreasing velocity filtration is one of the oldest and easiest methods of filter control. Used with multiple filter cells, this type of system controls the rate of treatment through a cell in the effluent or the discharge of the filter.
Organizational control systems allow executives to track an organization's performance, identify areas of concern, and then take steps to address those concerns. The operational control process (also called business control) allows strategic plans to be converted into operational plans. Strategic control includes agencies that formulate and enforce policies, such as law enforcement; tactical control includes direct services, such as financial assistance and credit and insurance companies; and operational control includes oversight bodies, revenue collection, and resource allocation. Selecting the size of the valve is critical for operation, and it should be made so that a small change in its position does not dramatically change the flow through it.
Improving clan control was the goal of sensitivity training groups (or T-groups) that were used in many organizations in the 1960s. Clan control is often used to a large extent in environments where creativity is vital, such as many high-tech companies. When operating a filtration system, it is important to consider how a filter's operational control system affects or is affected by control processes throughout the plant.
