The Service and Support building provides a centralized facility for several plant support functions. This building houses offices for plant administration, laboratory services, a central operations control center, training facilities, conference rooms, plant maintenance functions, and locker rooms for plant staff. The location of all of these activities within one building promotes frequent contact between plant personnel and enhances communication, and interdepartmental coordination.
Administration - The Service and Support building includes approximately 2,800 square feet of general office space for plant administrative functions. Specific functions served by this facility include a reception area open to the public; general office functions including word processing, file maintenance, and reproduction; drafting equipment and construction drawing record maintenance; plant process analysis and discharge permit compliance; industrial pretreatment program; plant safety program; cost accounting; budgeting; planning; and administration of service and ongoing construction contracts. The facilities include several personal computers with data and file exchange capability via a local area network.
|Summary of Area Control Centers|
|Headworks building, trickling filters/pumps, odor control system, chemical building|
|Blower building, secondary sludge pumping, solids contact tanks|
|ACC 4||Solids handling building, DAFTs, tunnels, disinfection system, chlorine contact|
|ACC 5||NTFs, NTF pump station, alkalinity system|
Operations Center - The plant operations control center (OCC) serves as a central monitoring point for all plant operations. It contains a central control room with wall-mounted graphic display of major process equipment status and alarm annunciators. In addition, two personal computers provide access to a supervisory control and data acquisition (SCADA) system and a display of all current plant alarms. All alarms automatically annunciate and print out on the video display of the second monitor. Alarms can be broadcast throughout the plant or to specific process areas via the plant intercom system.
The SCADA system receives status indication and process variables from five separate local area control centers (ACCs) located in the different process buildings throughout the plant site. Operations staff may access any data or equipment status by calling up a graphic display of the appropriate process system on the video monitor.
The OCC serves as a muster room for operations staff to meet and exchange information between shift changes. In addition to the central control room, the OCC includes offices for the operations superintendent and two shift supervisors. A boot wash room located adjacent to the plant staff entrance to the building provides space to wash and store boots, raincoats, and other field gear. A storage room adjacent to the OCC provides a convenient place to keep sampling devices, manual valve keys, portable instruments, safety equipment, and other operations equipment.
The plant control system is primarily manual. Individual system components may have automatically controlled functions within the component but are started or stopped by the operator. The plant has been divided into five separate areas for control and equipment status monitoring. Power and equipment control and status is provided at these local Area Control Centers (ACC). The ACCs contain Motor Control Centers (MCC), Programmable Logic Controllers (PLC), and annunciators for alarms and other manual controls for equipment within the area it serves. Control of equipment can be performed to various degrees at the ACCs, but the OCC is only a central monitoring point. Operating status of the individual pieces of equipment in a sub-area are transmitted to the ACC and then from the ACC to the OCC. Locations of the various Area Control Centers are listed in Table 5-3.
Each piece of equipment can also be controlled from its actual location using Local Control Panels (LCP). The LCPs may have additional control not available at the ACC. Alarms are always annunciated or indicated by status lights at the LCPs, ACCs and the OCC. In some cases, a general trouble alarm covering a variety of alarm conditions will annunciate at the ACC and OCC locations. Operations staff must then consult the LCP specific to the alarmed equipment to ascertain the specific cause of the general alarm.
Laboratory - The laboratory provides analytical support for a variety of functions including plant self-monitoring for the monthly DMR report; process data for operations control; periodic special studies to assist the CDH, DRCOG, and other regulatory and planning agencies in developing environmental data; monitoring of agricultural sites used for beneficial utilization of plant biosolids (digested sludge). The laboratory is equipped with several standard analytical instruments including gas chromatography, mass spectroscopy, atomic absorption, auto-analyzer for nutrients, automated BOD, and has facilities to support wet chemistry, solids analysis, bacteriology, and bioassay functions.
Maintenance - The 8,600 square foot maintenance center provides equipment and facilities for both routine and emergency repairs of virtually all the equipment at the plant. Maintenance center facilities include office space on the second floor overlooking the shop floor. A three-bay service area with overhead bridge crane provides space for multiple repair operations to proceed simultaneously in an orderly and logical sequence. An automatic storage and retrieval (ASAR) system provides compact and secure storage and control of small parts inventory. A walk-in paint booth accommodates virtually all of the mechanical equipment on the plant site, allowing high quality coatings for corrosion protection to be applied. A welding fabrication area is equipped with local jib crane and articulated fume hoods to facilitate equipment repair and fabrication activities. Service air to drive air-powered tools is provided from a central air compressor system located in the dewatering building adjacent to the maintenance shop.
The maintenance shop has an H-4 occupancy classification which requires segregation from the rest of the Service and Support Building in the event of a fire. All doors and windows between the maintenance area and the rest of the building are therefore equipped with automatic fire doors or louvers which shut when a fusible link in each device is actuated by smoke or heat.
Locker and Shower Facilities - To promote health and hygiene, plant staff are encouraged to wash frequently and shower at the end of each shift. Locker rooms provide two lockers for each person so that clean street clothes and uniforms may be segregated from work boots, and soiled plant uniforms. All lockers are ventilated by forced draft to maintain fresh, dry conditions. All floors in the area are ceramic tile and all exposed walls are glazed masonry block to minimize daily cleaning and maintenance.
Heating and Ventilation - Heating and cooling for the Service and Support Facilities is provided by a central hydronic system located in mechanical equipment room 720 on the second floor of the building. Hot water supplied by boilers BLR 9050 and BLR 9051 is circulated by four heating water pumps in a continuous constant rate circulation loop through heating coils inside the four air handling units (AHUs) which supply various portions of the building. The amount of heat transferred to the supply air is controlled by a bypass damper located in front of each heating coil. The intake air stream is split by directing part of the air flow around the heating coil with the bypass damper. The heated fraction of air passing over the coil is then blended with the bypass air to achieve the desired supply air temperature. The constant rate flow of hot water through the heating coil prevents the coil from freezing during extreme cold weather. The cooling system is analogous to the heating system with an evaporative chiller providing cold water to cooling coils in the three AHU units which supply air to the office, laboratory, and locker room areas of the building.
The Service and Support Building is segregated into four discrete air supply zones served by separate air handling units (AHUs). Two AHUs serve office space located in the administration, operations control, and maintenance areas of the building. These units are connected to return air ducts to recirculate air through the system and minimize building heating and cooling energy demand. The other two supply air units provide 100 percent fresh outside air to the laboratory and maintenance shop areas. Chemical and exhaust fumes and other air contaminants generated in these locations make use of the return air undesirable. By means of heating and cooling coils inside the AHUs, supply air temperature to the whole building is maintained at year round set point of approximately 65 degrees F.
In addition to the heating and cooling coils located inside the AHUs, most of rooms in the building are equipped with an additional hot water heating coil located in a reheat box in the supply air duct above the ceiling. Hot water from the boilers is circulated through these reheat boxes at a variable rate controlled by a throttling valve. The control valve adjusts the amount of hot water flowing through the reheat coil to raise the supply air temperature to match the temperature set on a thermostat located in the heated space. The individual room thermostats allow the temperature in each room to be independently adjusted to accommodate the needs of individual occupants.
Conference and Training - This area includes a room dedicated to ongoing staff training. It is used to house reference materials, O&M manuals, and audio/visual equipment both to record training sessions and play back prerecorded or commercially produced training video tapes. A combination conference and lunch room provides sufficient space to allow group meetings with virtually all of the plant staff in attendance at the same time. This space is also used for public education purposes during plant tours and similar functions. The conference room may be separated from the lunch room by means of a folding partition wall. A kitchen has also been provided for staff use.
Warehouse Facilities-The existing maintenance facilities located in the service and support building provide space for offices, equipment breakdown and assembly areas, paint booth, welding area, tool storage, and small parts storage. In addition to these facilities, warehouse space is needed for large parts, spare equipment subassemblies, chemicals, piping and valves, spare motors, other electrical equipment, and other materials used for routine maintenance of the plant.
These large parts and materials are currently kept in temporary storage in the former cryogenic system compressor building and several other temporary locations throughout the plant. This building has three existing overhead garage doors and sufficient space to house several vehicles and mobile equipment which currently are left outside.