How to Brew Beer without Water

THROUGHOUT many parts of the world we encounter areas or entire regions where water is scarce and water quality highly suspect. In these situations beer quality is often compromised and production schedule disrupted. The use of properly treated effluent presents the brewer with a safer option and greater security of supply.

There is little doubt that today technology exists to cost effectively and sustainably remove all pollutants from brewery effluent streams, and produce a water quality that is chemically safe for human consumption as well as a chemistry entirely compliant with even the most stringent of compliance schedules.

The biggest argument for reusing treated effluent is that its chemical quality far exceeds that encountered in most borehole abstraction schemes and in fact is closer to that of water used in hospitals for kidney dialysis. After all, many large cities in the developing world, with populations in the several millions, do not have even basic sewage treatment and disposal systems or landfill facilities. A large portion of this waste load ends up in the groundwater very prone to being heavily polluted, chemically and pathogenically. The thesis of this article is that we should reuse effluent with no domestic sewage.

There are many up sides to the practice of water recycling in breweries besides improving security of supply, reducing water ratios and the resultant reduction in its environmental footprint. Part of the treatment train – anaerobic digestion – reduces about 85% of the organic content of the effluent by converting it first to volatile fatty acids and then to methane. This not only affords the opportunity to replace around 10% of the fossil fuel use in the boilers, but also reduces the need to consume electricity in downstream municipal or collective treatment plants. A 1 Mhl/yr brewery can produce as much as 0.46 MW of power from the anaerobic digestion of its effluent, and in addition save a further 0.11 MW of power utilisation at downstream municipal sewage treatment plant, giving a net advantage of 0.57 MW.

Treatment also removes nuisance nutrients such as nitrogen and phosphate and prevents them from entering the receiving environment.

Aggressive recycling programme

Many breweries today are audaciously setting their sights on ever diminishing water ratios, some as low as 2.2 hl:hl. Such targets are not achievable without aggressive recycling of treated effluent. A 20-year-old brewery with old equipment but a reasonable water management programme may achieve a water ratio of 4.2 hl:hl. Recycling 65% of the brewery’s effluent leads to an approximate 50% reduction in the volume of water that needs to be brought on site and has the prospects of reducing the water ratio to 2.2 hl:hl.

A further advantage of this recycling programme is that it leads to reductions in specific water usage at certain user points. The softness of the recycled water or low TDS of the RO water at around 15 mg/l tolerates more concentration cycles in the boiler feed, condensers and cooling towers before requiring blow down.

This reduction in water usage takes on extreme significance in breweries that are embedded in water-scarce communities. A typical 1.5 Mhl/yr brewery at a water ratio of 7 hl:hl  will consume the equivalent water of 35,700 people and can be conceived as an irresponsible guzzler. Put another way, that same brewery will consume in one day what a developing world family will consume in 14 years. In these circumstances, it is difficult for the brewery management to claim good environmental performance without demonstrable evidence of water recovery.

Experience in several breweries suggests that, as a rule of thumb, recycling should be limited to 60-65 per cent of the eMujer