Being off grid – Sustainable water and energy management at the Bulungula Lodge

Submitted by: Maximilian Grau, Monday, December 9, 2013

<p>PV installation on rooftop of main building (Image source: Maximilian Grau)</p>

PV installation on rooftop of main building (Image source: Maximilian Grau)

Located in a deep rural area in the Eastern Cape, 30 km south of Coffee Bay, the Bulungula Lodge is one of the first lodges in the world to be Fair Trade accredited. The Bulungula Lodge was founded in 2004 by Dave Martin, who had to face a great challenge when construction of the lodge first commenced. Much of the surrounding region is without public electricity or water supply and the roads that feed the area were only accessible with a 4x4 vehicle. Part practicality and part philosophy Martin created an off-grid tourist lodge applying sustainability principles, with sustainable water, sanitation and energy management interventions, “sustainability was both a practical motivation and a philosophical one, personally and for guests” says Martin.

Battery pack with inverter for fridge, freezer and washing machine system (Image source: Maximilian Grau)

Energy management

The Lodge is powered entirely by solar PV. Two systems are installed, one for fridges, freezers and washing machines and another to supply the lodge infrastructure which include three laptops, about 50 lights, one satellite phone, for charging cell phones, two wireless routers, one small water pump, one music system and a charging station for guests.

The fridge, freezer and washing machine PV system is a 1.3kWp system with 18kW battery storage, consisting of deep-cycle lead-acid batteries (12x 2V batteries in series) and a 1.6kW converter. This PV system replaced old equipment, which was powered by gas. “The investment costs of R 70,000 for the PV system are paid back within two years due to the savings on gas” says Martin.

The second system to supply the lodge infrastructure is a 1.2kW system with 18kW batteries (same type and configuration) and a 900W inverter. The investment costs were about the same as for the other system. The battery storage for both systems are sufficient to bridge four very cloudy or rainy days without running lower than 60% capacity. In order to save on the electricity generated after a period of cloudy weather, lodge guests are reminded not to charge their laptops and other non-essential items. A sign is posted above the charging stations.

Water management

During the first years of operation only rainwater and water from a small spring nearby was available for daily consumption such as drinking, cooking, washing and showering. The rainwater was collected in storage tanks with a total capacity of 30,000L and was used for drinking and cooking. The spring water was used for washing and showering. Despite the large storage capacity of the rainwater storage tanks and the nearby spring, the lodge nearly ran dry after long dry winter seasons since the lodge opened. Three years ago Martin took a risk to improve the water supply by drilling a borehole without knowing if the water quality would be of good quality, as “a borehole, which was drilled about 1km inland had unusable, salty water” he explained. But the investment of R 30,000 (for drilling only) was worthwhile as the borehole water was of good quality, which was tested by the CSIR, and does not require any further treatment.

The borehole water is pumped about 200m with a solar and wind powered pump (flow rates ranging from 1,000 – 2,000L per day) into storage tanks (around 7,000L storage capacity) located behind the lodge on a small hill approximately 7m higher than the lodge itself. The height difference creates enough hydrostatic pressure in the distribution system to feed all taps and showers. The borehole water is used for drinking, cooking and showering. The rainwater is now used for washing, and the spring is no longer used.

A unique installation at the lodge is the “rocket shower” generating hot water for showering at the point-of-use. Paraffin with a bit of toilet paper is used in these showers to heat the water in a narrow steel pipe. Around 100ml paraffin is prepared in small containers for each shower, which is sufficient for a ten minute shower. One solar thermal system has also been installed to demonstrate its applicability, “but the operation is problematic as guests want to take a hot shower at any time” says Martin, “and this can’t be granted in peak season with a solar thermal system on overcast days and in the evening”. The water consumption can also be better controlled with the rocket shower as the water cools down as soon as all paraffin is used up. Guests are thus less likely to spend a long time under a hot shower using too much water.

Rocket shower installation, with opening on the bottom where paraffin and toilet paper is inserted (left); paraffin containers to use for one shower (right). (Source: Maximilian Grau)

The investment costs for the water infrastructure are as follows: pump and energy supply are about R 18,000 (without borehole), tanks and piping sum up to R 10,000 and the rainwater infrastructure was around R 20,000. The running costs are minimal, only manual labour to clean clogged pipes and general maintenance is required. The paraffin costs R 1,200 for about 100L.

Wastewater and sanitation management

Wastewater from the kitchen and at the showers and hand washbasins are treated in different ways. The kitchen wastewater requires several treatment steps. A fat trap is installed as pre treatment to remove greases and solids, and a constructed surface flow wetland serves as secondary treatment. The plants in the wetland are placed on a grid above the liquid level letting only the roots into the wastewater streams. “This reduces the chance of clogging and the roots act as an additional filter” said Martin. The last step is a soak away with banana plants to take up most nutrients and treat the wastewater sufficiently. The set up is located behind the kitchen with an approximate footprint of 30m2.

But what makes the lodge operation exceptional is the sanitation infrastructure. Guests won’t find flushing systems for the toilet or urinals. Instead, Martin chose a dry sanitation technology, which does not require any water for the ablution facility. It consists of Urine Diversion (UD) toilets and waterless urinals. The UD toilets separate urine from the faeces by a divider in the pedestal allowing the faeces to decompose. The urine is guided into a soak away with banana plants at the back of the toilet block. Initially the user had to put a cup of soil into the faeces chamber after each use to support the drying process. But recently the operation has been changed and a cup of organic material (saw dust) is being put into the chamber by cleaning staff three times a day, “given the better drying and decomposition properties” said Martin. Ash is applied once per day at 6am as cover material. The faeces are collected in special containers under the pedestals and emptied regularly. To improve ventilation 5m long, black painted pipes with fly screens on top are installed on the outside of the ablution block. The pipes are connected to the faeces chamber with right angles through the wall to avoid having to go through the thatch roof which would cause leaks. Recently a compost bin was constructed nearby the ablution facility, to compost the faeces on-site.  Before, the faeces were buried in a remote place in the forests. The benefits of this dry sanitation system include minimal operation costs and no water use.

UD toilet pedestals have a divider in the toilet separating the urine from the faeces (left). The recently constructed compost bin (right). (Source: Maximilian Grau and Dave Martin)

The surrounding community

Guests will not only find this different off-grid approach appealing but also the management structure of the lodge. The community is responsible for the operation as the community “owns 40% of the lodge and is an integral part of daily life here” explains Martin.

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Maximilian Grau