Recycled domestic wastewater creates savings

Water is becoming increasingly scarce across most of the EU, with water restrictions becoming more and more common. The problem is, unfortunately, unlikely to decrease in the foreseeable future due to predicted warmer climates, which may exacerbate the water shortage.

One step towards a sustainable solution would be the development and implementation of household systems capable of recycling shower and bath water (so-called grey water). Significant challenges exist, however, in the form of high installation costs and the lack of suitability of the system for installation in domestic settings.

The AQUACONSERVER project overcame these challenges by designing a low-cost water and energy recycling system that can be effectively installed in around 90 % of households.

Researchers investigated a range of membranes for their ability to remove pathogens and other contaminants from grey water. An investigation into pore size revealed that a tighter pore dimension filter was always needed in the system to adequately reduce the microbial load.

An important component of the system was a water quality sensing device, containing turbidity, temperature, conductivity and chemical sensors. A useful heat exchanger also formed part of the system and played a role in harvesting heat energy from wastewater for reuse in water heating. The project also witnessed the manufacture of a full-scale 'shower tray' prototype.

The project resulted in a low-cost bathroom water recycling system that could be retrofitted and was capable of reusing water from showering and bathing. This enabled savings of up to 50 % of personal washing water usage and more than 50 % of personal associated heating energy usage. In addition, the system was capable of using grey water to flush toilets, thereby saving up to 35 % of household water usage.

AQUACONSERVER is superior in terms of water saving and water quality to conventional grey water recycling systems and can compete very effectively in both the grey water systems and shower systems markets. The potential European market for the system is around 2 million units per year, with an average growth rate of 5 %.

It is likely the system will be sold in combination with a new shower or shower cubicle, which will increase overall revenues for AQUACONSERVER members. At the same time, the system has the potential to cut the water bills of European households by over EUR 27.8 million and household energy bills by up to EUR 18 million.