When director Peter Jackson went searching for Hobbiton for his Lord of the Rings trilogy, wastewater treatment was probably the farthest thing from his mind. He discovered Tolkien’s picturesque world in the rolling hills of a sheep farm in an isolated corner of New Zealand. When the movie set became a tourist attraction with a new pub, a recirculating textile filter was cast in the role of lead wastewater system.
The Tourist Attraction
Since 2002, Jackson’s set has doubled as a tourist attraction welcoming more than 300,000 visitors. Recently, in conjunction with the premier of The Hobbit, tour operators added a functioning pub to the site so that fans could share a pint of their favorite Hobbit beverage, much as the characters do in the films. The addition of the Green Dragon pub required wastewater infrastructure to handle the discharges from its kitchens and restrooms. However, this rural area lacked centralized sewers.
Subsurface drip irrigation in the sheep paddock. Photo courtesy of Innoflow Technologies
An alternative wastewater system that could accommodate the increasing number of tourists expected to visit after the release of Jackson’s latest film was needed. A New Zealand distributor was contacted by Alistair Osmond, the project engineer, to provide a treatment system (installed in November of 2012) to fit the special needs of Hobbiton’s off-grid, sewer-less environment.
Remote locations such as the film set are ideal for elaborate movie scenes. However, everyday needs, such as wastewater treatment, often become a challenge. Free-standing, decentralized systems are ideal for isolated locations that lack, but still require, suitable plumbing.
The Treatment System
The system consists of two specialized filter pods, but it was designed with expansion in mind. A proposed visitor center to accommodate bus tours and a plan for a wedding facility could expand the system to three filter pods.
The treatment system uses an engineered textile media to treat wastewater that is capable of meeting stringent regulatory requirements. Influent is intermittently recirculated over the textile media, which houses the cleansing aerobic bacteria, similar to the operation of a recirculating sand filter. A buffer tank precedes the recirculation tank, so the system provides consistent, reliable treatment, even under peak flow conditions.
The wastewater treatment system. Photo courtesy of Innoflow Technologies
Alternating duplex pumps (50 gallons per minute, 1 horsepower, 220 volts, 50 hertz, single phase) recirculate the effluent through the filters at an approximate 3:1 recirculation to discharge ratio. The pumps use a super stainless, 4-inch submersible motor. The treatment system company has been using the same submersible motors for more than 25 years. They have a corrosion-resistant, stainless steel shell, with stainless steel internal components and nitrile rubber seals.
The internal features of this motor include hermetically-sealed windings, a Kingsburg-type thrust bearing, pressure equalizing diaphragm and built-in lightning arrestors. The 2-wire starting switch aids and prevents extremely fast cycling.
The effluent pumps were inspired by the required longevity of well pumps and were designed to transport screened effluent with low suspended solids. The pumps are capable of 24-hour run-dry with no deterioration in pump life or performance. A patented 1/8-inch (3-millimeter) bypass orifice ensures flow recirculation for motor cooling and to prevent air bind.
The pump’s liquid end is specifically designed for wastewater applications. Diffusers and discs are made of an abrasion-resistant polyphenylene oxide/polystyrene blend. The pump is field repairable.
The Hobbit’s New Zealand movie set now has a new pub. Photo courtesy of Orenco Systems®, Inc.
All electrical components of the treatment system are monitored by a remote telemetry system. Pumping from each tank—buffer, recirculation or discharge—is controlled by pre-set timers at the panel. Flow is monitored and surges are modulated by a three-float assembly that triggers a time override/high-level alarm or a redundant off/low-level alarm. Other features of the panel are:
- Surge arrestor
- Enclosure heater
- Current sensor for the filter fan
- Current transducer and 20-amp circuit breaker for each pump
- Audible/visible alarm
- Ground fault circuit
Following the filter pods, treated effluent is discharged by alternating pumps (30 gallons per minute, ½ horsepower, 220 volts, 50 hertz, single stage) with a floating impeller design. Effluent flows through a water meter and to a pressurized drip system. The clear, odorless effluent is ideal for reuse applications. For example, at Hobbiton, the effluent is used to help irrigate one of the sheep pastures.
Many types of systems are capable of secondary treatment, but the Hobbiton system and its components were chosen for highly cost-effective operation over the life of the system, using little energy and requiring minimal maintenance.