Whiskey is a big part of the Scotland culture as bagpipes, haggis, and the kilt along with a few drinks invoke poetry, but there is an environmental problem with it. According to "industrial wastewater treatment, recycling, and reuse" "Distilleries are considered as on of the most highly polluting industries worldwide. The wastewater generated from a distillery unit is dark brown in color and contains very high biological oxygen demand (BOD), chemical oxygen demand (COD), and high BOD/COD ratio. The amount of organic substances such as nitrogen, potassium, phosphates, calcium, and sulfates is also very high."
Obviously, it's not just Scotland's distilleries that are the problem, most developed countries have distilleries for producing a wide range of spirits, and whiskey is often the flavor of choice for their residents. But this wastewater causes problems for the environment and in countries where public health is less developed, this wastewater can be fed back into the public drinking water system without much treatment. In the past, much of this water was used to water the same crops that are used to produce the spirit because its high nitrogen, phosphorous content, however, the dark brown coloring, odor, and purification caused concerns.
One method of treating this water is through the use of membranes and membrane separation techniques. Membranes, which loosely involves sending the contaminated water through a series of elements such as sand or gravel, either using gravity or high pressure and are an essential but relatively new part of the water filtration process, but they're just one part of the physical treatment of wastewater which also includes: sedimentation, screening, aeration, filtration (Membrane Technologies), and flotation.
Distilleries also use a large amount of gas while they produce their alcohol and as energy prices increase this is going to cause price increases. To offset this increase, a new distillery in Speyside has invested 17 million pounds on building a bioenergy plant which generates energy by burning the byproducts of the distillation process such as spent grains and produces enough energy to power 10,000 homes (8 - 10 megawatts). Unfortunately, this isn't enough and the distillery only gets about half its energy from the plant, with hopes to increase this to 80% in the future.
But despite this, many of the distilleries are in remote locations where access to piped gas and oil isn't possible or is just too expensive, so bioenergy is a more economical and environmentally friendly way of using spent grains that otherwise would have become animal feed.
Commercial alcohol production is an environmentally unfriendly process but through the development of better filtration and more renewable energy, it my become better.