Agenda - 10-08-1991 - Laserfiche WebLink

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number of potentially severe disadvantages to pum systems. Mechanical pumps and electrical controls cause all pump systems to i be much more maintenance intensive than gravty flow septic systems. Proper maintenance of a system becomes even more critical with the low pressure system, which requires periodic inspection of the nitrification lines for stoppages and excess line pressure in addition to pump inspection. The location of nitrification fields in areas remote from the occupied building can be disadvantageous if it allows surfacing of waste water in the nitrification field or other similar system failure to go unnoticed and uncorrected. Such situations require a commitment to periodically inspect nitrification fields as necessary to forestall system failure. in law pressure systems in particular, unchecked operational problems in the' nitrification fields can render the field permanently unusable. Failures in pump conventional and low pressure systems generally result in untreated effluent running into surface waters or entering ground water. Class III system - Individual Spray Irrigation Systems and Sand Filter Discharging Systems - Spray irrigation systems and sand filter systems have a number of elements in common with each other and with Class II pump systems. Spray systems generally consist of, in order, a septic tank, a sand filter, a chlorinator or other type of disinfection unit, a pump tank and pump, and a spray distribution system. Sand filter discharge systems generally dispense with the pump tank and substitute an effluent discharge line for the spray system. The sand filter in both the spray irrigation and the sand filter discharge systems is typically a buried, four sided concrete structure with a top and bottom. This structure is filled with sand and gravel filter media. Septic tank effluent is discharged to the surface of the sand. The effluent trickles through the sand, is collected in a pipe at bottom of the filter and flows through the pipe out of the bottom of the structure. The sand filter provides a second level of treatment (after the septic tank) to remove or filter out solids and provide exposure of waste solids to microbiological decomposition processes. In the sand filter discharging system, the sand filter effluent flows by gravity to the effluent discharge line where it is chlorinated or otherwise disinfected before being discharged to surface waters. Recent innovations in sand filter technology have produced the recirculating sand filter which can be used with the spray or the discharging system in lieu of the common sand filter. The recirculating system uses a pump to recycle waste water through the sand filter several times before it is discharged or pumped onto the spray field. 6