Room 185: Freshwater Research Room

This aquatic research room has two 1.2 m diameter tanks and nineteen 0.6 m diameter tanks located within the holding area.

Room: The walls are epoxy coated concrete block and the floor is a specially hardened concrete to prevent water penetration. There is a grate covered trench located along the center of the room. The drain line for the tanks is located within this trench, as is a drain to the sanitary sewer. Air temperature in this room is monitored, but is not under the Argus™ system’s control.

Tanks: There are two 1.2 m tanks, equipped with dual internal stand pipes located in this room. The outer standpipe sits higher than the water level in the tank. Holes have been drilled through the bottom of this pipe to effect a self cleaning action for the bottom of the tank. Water is drawn through these holes and up over the inner standpipe. The inner pipe must still be briefly removed either every day or every few days depending upon internal load of fish, to clear waste build-up.
The nineteen 0.6 m tanks have cone shaped bottoms. A perforated PVC screen is placed over this cone to prevent fish from going down the drain. The tanks are designed to self clean. Waste drops through the PVC and is drawn down into the drain line. The cone shape acts to keep waste from settling in the tank. These tanks are also equipped with an external standpipe. The standpipe for these tanks must also be removed briefly either every day or every few days depending upon internal load of fish, to clear waste build-up. Aeration: Low pressure air for tank aeration is supplied through black ABS pipe that circles the room. Air is supplied from three 1 hp Gast regenerative air blowers located in room 174.

Power: Each room has eight 115 V electrical circuits. These are located around the perimeter of the room. Each has a duplex ground fault receptacle. A circuit breaker panel is located on the north wall inside the anteroom.

Lights: Lighting in this room is provided by weatherproof incandescent fixtures. This room has a fully programmable photoperiod (i.e., the photoperiod can be programmed to emulate that found at any latitude in the world or any artificial photoperiod that the researcher requires). At “dawn” the incandescent bulbs slowly ramp up in intensity, and at “dusk” they slowly dim. The time required to ramp to full intensity and the final intensity of the lights is programmable. The Photoperiod Alarm is set to activate if the lights do not turn on or off as the program requires. The lights can be turned on manually from the Argus™ panel located in the hall. An alarm situation will occur if the lights are left on manual for too long.

Anteroom

Room: The water treatment system is located in the anteroom and consists of a 2 m x 2 m x 1.5 m deep sump with a gravel bed filter, two pumps, a gravel filter with manual backwash valve, a sand filter with automatic backwash valve, a pair of two bulb UV sterilizers and one plate heat exchanger. Water supplied to each of the 1.2 m tanks in this room first passes over a biofilter to convert ammonia to nitrate. The anteroom is also supplied with a sink with hot and cold domestic water, and cupboards above and below the sink for limited storage of chemicals and equipment. A fire extinguisher is located beside the door. Windows in the doors provide visual access to both rooms, the animal holding room door has a small door over the window.

Water Temperature Control: Water temperature is controlled and monitored by the Argus™ system and consists of one plate heat exchanger supplied with hot or cold glycol. Water temperature is monitored going in and out of the exchanger by thermistors located in the pipes. These thermistors are set to activate an alarm (Water Temperature Deviation Alarm) if the water temperature deviates from the target temperature by a preset margin. The computer control system regulates the position of two two-position three-way actuated valves to provide either hot or cold glycol. An actuated modulating valve regulates the amount of glycol supplied to the heat exchanger to maintain the target water temperature. The range of water temperatures in this room is approximately 4°C - 25°C. There is a small amount of flexibility in the system, which is governed by the flow rate of water through the exchanger and the surface area of the plates found in the exchanger itself. The Aqualab has spare plates to increase the capacity of the exchanger if the need arises. Water temperature in this room is set for 10°C.

Water Replacement: Water is added to the room’s recirculation system on a regular basis. The volume added is controlled by the Argus™ system which in turn controls the> make-up water solenoid valve. The make-up water system is composed of a paddlewheel flow sensor and a solenoid valve on a 1" PVC supply line . Water is fed directly from Aqualab’s pre-filtration system into the room’s sump pit. 50,000 L of water are added in pulses of one minute duration, 325 times a day. The number of pulses per day is determined by the volume of water that passes the paddlewheel flow sensor in one minute. Water Recirculation: Water is recirculated around the room from the sump pit to the tanks and back again. Waste water enters the sump pit by first passing through a rotating screen filter. This filter removes the large particulate material (excess feed and faeces)from the water stream and directs it to the waste water sump pit in room 174. The water is then drawn through a gravel bed filter by the recirculation pumps, located in the pump pit. Water is then pumped through the UV sterilizers and the plate heat exchangers. After the water is filtered, sterilized and the temperature modified, it travels to the tanks in the animal holding room. Water overflows stand pipes located either within the tank or beside it and returns via drain lines to the sump pit. The drain lines are found in the trench. Each 1.2 m tank or each set of four 0.6 m tanks has a set of blade valves to direct flow either into the trench (for cleaning and disinfection) or back to the sump (for recirculation). Recirculation water flow is monitored by a paddle wheel flow sensor which is set to activate an alarm when flow drops below a preset level (Low Flow Alarm). The preset level is dependent upon the minimum required water flow.

Biofiltration: The biofiltration in this room is accomplished in the gravel bed located in the sump pit. New biofilters need time to grow bacterial cultures. Nitrosomonas sp. grows first, converting ammonia to nitrite. There is a lag time before Nitrobacter sp. starts to grow. It is during the time that Nitrobacter sp. is becoming established that elevated levels of nitrite could become dangerous to fish. Nitrobacter sp. converts nitrite to nitrate a much less toxic form of organic nitrogen. Biofilters should not be allowed to dry out. This is particularly important in marine systems, dry-out will result in sterilization of the biofilter.

Pump Pit: A float switch is located near the bottom of the pump pit to indicate water accumulation in this pit. This switch will activate an alarm as soon as it is triggered (Flooded Pump Pit Alarm). This alarm’s purpose is to protect the pumps from immersion in the event of a leak into the pump pit.

System Water Volume: The water level in the sump pit is monitored by an air pressure level sensor. When the water level drops below a preset point the make-up water solenoid valve opens. Water is added until the sump is once again full. If the water level drops below 70 cm in depth an alarm is activated (Low Water Level Alarm) and the make-up water solenoid opens. If the water level drops past 30 cm, the pumps will be turned off by the control system, to protect them from burnout. This will activate another alarm (Low Flow Alarm). When the water level rises above 30 cm the control system will reactivate the pumps, thereby restoring flow. When the water level rises above 70 cm the Low Water Level Alarm will be deactivated.