Finding an Off-Grid Wastewater Solution

The Gondwana Rainforests of Australia, including Main Range National Park, are designated as a World Heritage site by UNESCO, the United Nations Educational, Scientific, and Cultural Organization. Traversing the park, Spicers Scenic Rim Trail has been developed as an ecotourism experience, allowing visitors to spend 2-7 days exploring the trail with an expert guide, then staying each night in a luxury eco-camp featuring hot showers and chef-prepared meals.

The system at each site is equipped to meet strict treatment limits on dispersed effluent.

The trail first opened in 2009, with an extension opening in 2020 as part of the Queensland Ecotourism Trails program. Included in the extension were the Spicers Amphitheatre and Spicers Timber Getters overnight camps. Both were designed to be off-grid, with power generated by the sun and water supplied by the rain. As for how to handle the wastewater and its higher than usual waste concentration due to low-flow water fixtures at each camp, an expert consultant provided a short list of options that included an AdvanTex® Wastewater Treatment System. These systems have been manufactured by Orenco Systems® and installed all over the world, including in locations that are environmentally sensitive and require high levels of treatment quality and efficiency.

Treated effluent from the AdvanTex® AX-MaxTM system is clean enough to be reused as subsurface irrigation. Left to right, the storage tanks at this off-grid camp contain treated AdvanTex effluent, rainwater for fighting bushfires, and rainwater that will be treated and used as potable water.

ENVIRA Holdings, the consulting engineer and local Orenco distributor, provided further information on the treatment process and recommended a customized AdvanTex® AX-Max™ system with enhanced nitrogen reduction capabilities as the most appropriate solution for each camp. After carefully considering various alternatives — and meeting extensively with government regulators, environmentalists, and ENVIRA staff — the development team chose the AdvanTex option. ENVIRA had demonstrated an in-depth knowledge of onsite wastewater treatment and best-practice environmental management, both extremely important factors on this ecologically sensitive project. In addition, the AdvanTex system offered many advantages, including low power consumption, strong nitrogen-reduction capability, effective treatment of seasonal flows, process reliability, operational efficiency, simple maintenance requirements, and portability.

The AX-Max is a multi-chambered unit that produces high-quality effluent with particular emphasis on nitrogen reduction. The system includes the textile media, treatment chambers, pH-augmentation input feeds, pumps, disinfection, and control systems — all in a prepackaged unit that’s easy to transport and install, minimizing impact to the site.

All AdvanTex treatment systems use a fixed-film, attached-growth treatment process and are an excellent solution for a variety of applications. In an AdvanTex system, small doses of blended wastewater filtrate are uniformly distributed onto the textile media throughout the day using timer-operated pumps. This maximizes contact time and ensures an unsaturated and highly aerobic environment, resulting in optimal treatment performance.

Low-horsepower, high-head turbine pumps operate intermittently, with sophisticated controls that automatically adjust recirculation ratios and pump run-times based on daily flows. These pumps are lightweight, extremely robust, and field repairable.

Custom designed to work together at the campsite, these AX-Max units feature an 8300-L (2200-gallon) tank that's divided in half to accommodate both primary and pre-anoxic chambers.

Given that both camps were being constructed in remote areas of the mountainous trail, the greatest installation challenge was transporting the treatment units to each site. The only vehicle capable of delivering the units up and down steep inclines and through tight turns on narrow tracks was a 6 m (19.7 ft) ex-military vehicle. Fortunately, the versatility and superior engineering of the design could be split into two units per site, each unit measuring just 4.3 m (14 ft) long, making the trip up the mountain possible.

Known for their ease of maintenance, the installed units are monitored remotely by ENVIRA staff via an Orenco TCOM™ telemetry panel. ENVIRA coordinates a response to any control panel alarms and also provides quarterly on-site servicing of the entire system, while a site caretaker performs daily inspections and tasks.

Protected environments like the Gondwana Rainforests demand special attention, including the proper management of wastewater. At these two camps on the Scenic Rim Trail, this treatment technology is performing reliably and providing enhanced nutrient reduction, even with high organic loads. The rainwater that’s collected and used in sinks, showers, and toilets is being safely reclaimed and reintroduced with minimal impact or risk to the local environment and its rare and endangered wildlife. WW

About the Authors: Bill Hensley is the international projects manager for Orenco, where he provides design, installation, and operational training and support for the company’s wastewater collection and treatment solutions.

Matt McKennariey is a co-director and founder of ENVIRA Holdings Pty Ltd, a specialist company that provides environmentally sustainable solutions for the treatment, recycling, and disposal of wastewater. With a background in environmental science and project management, he has focused his career toward sustainable water resource management, and has 15 years’ experience in the decentralized wastewater treatment industry.