WET News

Sewerage solutions for difficult situations • When gravity sewers are unsuitable, vacuum sewerage technology can provide the answers – and with multiple added benefits EXPERT VIEW T raditional gravity sewers are oen able to handle the majority of require- ments regarding transportation of wastewater from buildings to sewage treatment works, yet oc- casionally certain situations arise where – for any of a variety of reasons – they are unable to 10 WET NEWS APRIL 2018 | wwtonline.co.uk Aqseptence, not only detects any imperfect valve operation and immediately identifies in which vacuum chamber the valve in question is located; it also reacts proactively and automatically, for instance by completely deactivating and closing the valve, in order to prevent a temporary excess of wastewater from deleteriously influencing the whole system. The chamber management system can also be pro- grammed to automatically open and close valves at cer- tain pre-defined and pre-pro- grammed times – a very useful measure in situations such as may exist whenever a property is vacant for several weeks or months, and there has there- fore been no wastewater gener- ated for a longer period. The management system thereby counteracts any danger that might otherwise possibly exist of a reduced vacuum level at the valve in question limiting its performance. Information about the sta- tus and current operation of every single vacuum valve in a network can be obtained by suitably authorised personnel at all times, and in "real time" – as well as remotely – simply by logging in to the process control soware of the man- agement system, either with a PC plus the internet, or using a mobile phone. By this means may a valve, or valves, also be remotely con- trolled by authorised person- nel, provided a suitable modem has previously been installed and connected to the corresponding operating so- ware in the control cabinet. With such a management system is safety and security of network operation very signifi- cantly enhanced, so providing for even better vacuum sewerage. GEORGE MACMAHON INTERNATIONAL SALES MANAGER AQSEPTENCE-ROEDIGER Vacuum chamber with valves Vacuum sewerage network including vacuum station and wastewater tank SPONSORED BY possible cost savings that result are self-evident. In addition, any possibly required repairs later on are able to be effected quickly and efficiently, as the entire network is more easily accessible than is the case with many parts of a gravity sewer network. Such vacuum sewer net- works require special valves – supplied by Aqseptence, under both the "AIRVAC" and "ROE- DIGER" brand names – which are usually located in the below-ground vacuum collec- tion chambers, close to the buildings where wastewater is coming from. These are auto- matically activated, as soon as a certain pre-defined quantity of wastewater has been col- lected within the associated sump, also located within the vacuum collection chamber. The vacuum within the system then sucks this wastewater into the network, and trans- ports it very quickly into a holding tank, where it is collected, to be later pumped to a sewage treatment plant, pump station or existing sewer. Aqseptence not only supplies the above-mentioned valves and associated controllers, but also the required vacuum chambers, as well as the vacuum pumps (which generate the required vacuum). Also supplied are the holding tank (which doubles as a vacuum tank), the water dis- charge pumps, and the neces- sary process control items, including the control cabinet, required for operation of the entire system. A recent very significant development, leading to fur- ther improved automation effi- ciency and security, has been in the field of "chamber man- agement from a distance", viz. constantly remotely monitor- ing, as well as remotely influ- encing and controlling, system operation, to always ensure for best operation. This chamber management system, devel- oped and supplied by provide the best possible solu- tion, whether from a technical or cost perspective. This can, for instance, be the case when ground water tables are high, or where there is danger of flooding. Here, leaks – as well as manholes – in gravity sewer networks can lead to overfilling and result- ing problems. Vacuum sewer- age will eliminate this risk, as such a network – made up of fully sealed plastic piping – will not allow any ingress of water. By the same token, wastewa- ter cannot leak out into the ground – even if there were a hole or imperfect sealing some- where, the vacuum within the pipework will always entirely prevent any such leakage. Vacuum sewage networks, being well and tightly sealed in all places, will of course also never emit odours or smell unpleasantly. Another significant advan- tage is that vacuum sewerage technology can even enable wastewater to be transported, if necessary, upwards, viz. ver- tically. An example is a requirement for sewerage pip- ing to cross a river – without pumping, this is hardly possi- ble with a gravity sewer. A vac- uum sewer pipe can, however, easily be laid, either under or over the river (should there be a bridge there, along, or under which, it can run). The strong vacuum force within the pipework provides the additional benefit of always ensuring that wastewa- ter flows at a high speed – this in turn leads automatically to a self-cleaning effect, so keeping the pipework free of obstruc- tions at all times. Of course, vacuum sewers consist of plastic pipes that are of much smaller diameter than are gravity sewers, pipe diame- ters of just 110mm or 160mm being very typical. These are therefore not only much easier and quicker to lay down; they can also be laid at much, much shallower depths, with just 1.0 or 1.2 metres depth being possible. The very significant

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