Inland Waterways Systems
Inland waterway toilet systems must include a holding tank as currently all our canals and shortly, all our rivers and broads will require boats to retain their own waste which has to be discharged at suitable disposal sites.
Gravity discharge (dump through) toilets are the simplest and most foolproof of all holding tank toilet systems. Mounted on a suitably strengthened holding tank they are invariably supplied from the vessel's on board fresh water tank and, when flushed, allow waste to pass directly into the tank below. Dump through toilets should always contain a small amount of water in the bowl thereby preventing odours from escaping, however a tank with an inadequate breather or a tank which is not emptied regularly will encourage foul odours to lurk under the bowl and escape when the toilet is flushed./p>
Centrifugal and macerator toilets are similar in shape and size to household loos although, instead of having a cistern containing a large amount of water they have a pump inside the bowl together with all the necessary electronics which churns all the waste and discharges it into a remote holding tank. These toilets are normally supplied with flushing water from the fresh water system and water usage can vary from around 1.2 litres of water per flush to 3 litres of water per flush. Most of these toilets are very quiet in operation although care has to be taken that non suitable product is not placed in the bowl or blockages will occur and then it is rubber glove time!/p>
Vacuum toilets are considered to be the most efficient and cost effective of boat toilets, especially when used in conjunction with both an on board water supply and a holding tank. Using a minimal amount of flushing water they swiftly dispose of waste from the bowl, through the vacuum tank and pump and deposit the resulting slurry into a holding tank. On average a holding tank coupled to a centrifugal or macerator toilet will require emptying three times to every one of a tank connected to a vacuum toilet. Therefore the extra cost of the vacuum system can soon be recovered by the saving on pumpouts. Power consumption is very low at around 6 amps, even more so when you consider that a vacuum pump should only run for around 30 to 45 seconds./p>
Compressed Air toilets are the most "bomb proof" of boat toilets as their robust construction and large bowl discharge, coupled with a very powerful compressed system will deal with almost anything which is thrown at them. They do, however use more water than other boat toilets but are favoured by the many passenger boat operators plying our inland waterways.