R. K. Industries - Manufacturer of gear and vacuum pumps in India. Pumps are typically either vacuum or centrifugal. Vacuum pumps, the most common system used by septage haulers, have the following advantages: Iiquid does not flow through the pump, which reduces wear; the pump is less likely to freeze; and the tank contents can be discharged under pressure. Vacuum pumps should be equipped with a water trap to prevent dispersion of aerosols. Because liq-uid moves through the pump, centrifugal pumps are more likely to clog and wear more readily from grit and debris.

Centrifugal pumps are typically open-impeller or recessed-impeller for handling solids. Both types of centrifugal pumps have a maximum suction lift of about 27 ft (8 m). Some truck-mounted tanks are equipped with high-level automatic shutoff controls to prevent overfilling. Pump capacities are typically at least 400 gal/min (1,500 Umin). Hoses should be of high-vacuum black rubber or synthetic material, with a minimum diameter of 3 in. (8 cm). Hoses should also be capable of being drained and capped to minimize spillage. Haulers typically carry at least 100 ft (30 m) of hose. Discharge valves on the hauler trucks should be drip tight, and a discharge nipple should accommodate a quick-disconnect coupling. Other equipment includes a device for breaking up the scum layer (e.g., a long-handled fork), shovel, soil probe for locating the septic tank, and other tools to either measure accumulations or perform other tasks in the field. A squeegee and suction wand attachments should be carried ‘“The Pumper,” a monthly publication aimed at the liquid waste hauler industry, produces an annual directory of equipment suppliers that is free with a subscription to “The Pumper.” to help clean up any spills. Lime should also be available to apply to areas where septage has been spilled.

Mobile septage dewatering systems, originally developed in Europe, are now available in the United States. Withthese systems, septage is pulled from the septic tank into one compartment on the truck; filtrate is returned to the septic tank. Polymer or lime is added to the septage during transfer to a dewatering tank, where solids are concentrated. A sludge solids content of 15 to 20 percent is reportedly achievable for polymer and lime systems, respectively Mobile dewatering systems offer: Lower transportation costs due to fewer trips to the disposal site, greater truck capacity, lower volumes of material requiring further treatment and disposal. These advantages are best suited to areas with many septic tanks and long travel distances to the discharge site. Disadvantages include more complex operational requirements and high equipment investment costs.

After the septic tank has been located and the access hatches exposed, the inlet and outlet baffles or tees are examined for such problems as damage, loose connections, and plugging. Broken pipes or baffles should be replaced or repaired. If the liquid level in the tank is higher than the outlet pipe, this may indicate clogging in the outlet pipe or in the drainfield. Next, the scum mat is manually broken up to facilitate pumping.