Some manufacturers have chosen to adapt existing, conventional machines, while others have designed new recycling machines. Today’s machines have achieved a certain maturity, offering productivity, versatility and reliability, as well as having become safer
Recyclers are necessarily more complex and consequently cost more to build, buy and operate. They also require skilled, responsible operators and well-trained maintenance staff to make them work efficiently, saving huge amounts of drinking water.
The type of high pressure pump being used by the recycler determines the treatment processes required to condition stormwater effluents or raw sewage for recycling. Treatment systems range from simple, single stage strainers to intricate, multi-stage processes. Conventional high-speed triplex pumps require higher treatment standards as they are less particle-tolerant than the pressure transformer pumps, which are able to handle contaminated water with particle sizes up to 500 Micron or 0.5 mm OD.
The pressure transformer pump’s ability to handle high contaminant loads is based on the slow-stroking nature of the device (35 strokes per minute) and its valve system, which is specially designed for recycled water. Consequently, its water treatment system is less elaborate and is limited to a self-cleaning, rotating strainer process.Article continues below…
Triplex pumps require higher treatment standards to reduce contaminants from the pump water. With that comes increased system complexity and increased maintenance. Generally, multiple treatment stages are used to achieve a suitable water treatment standard to avoid excessive wear and tear.
Ideally, the system should have a recycling treatment capacity equal to the high pressure pump output; for example, a 400 litre per minute pumping system should have a continuous water recycling process at least equalling the maximum pump output. One of the primary benefits of a recycler is that it eliminates the need for costly water refilling stops and turn them into productivity gains. If a recycler has to stop production to allow the water treatment process to catch up then much of the productivity gains are lost.
Another benefit of a recycler is the use of increased water flows. Because a recycler re-uses the water and does not require refills, a much higher water flow can be used in the cleaning process, thereby reducing cleaning times. This results in increased productivity, improved efficiency, reduced fuel consumption and a host of other benefits to the owner/operator. Recyclers really come into their own with pump capacities ranging from 300 to 500 litres per minute at 200 bar (2,900 psi).
However, these treatment facilities and structures require space and add weight to a unit. Prospective buyers need to check vehicle tare weights and remaining payload capacity.
Flexible tank arrangements are an important aspect to consider. Most are built in stainless steel for a long, trouble-free life. Tanks that can be configured into individual compartments will offer additional flexibility for different applications. In this way, the unit can be configured for optimising different operating modes, such as recycling, hydro excavation, straight vacuum tanker work, super sucker mode, straight jet cleaning work, street flushing and surface cleaning modes.
A highly efficient vacuum system is paramount to catch the water for recycling purposes. The vacuum pump should be lightweight (for low tare weight) and of high performance.
The high suction power, plus the high air speed in the suction hose, quickly reclaims the water and removes debris. High performance vane pumps, blowers or alloy water-ring vacuum pumps work very well, with the latter being the lighter, more reliable and the least noisy.
Cassette suction (pictured above) booms are another recent development. This design combines a suction hose storage cassette with a slewing boom. Up to nine metres of suction hose can be stored.
Equipment drive arrangements are also a vital consideration. Vehicle engine-powered drives are preferred. Auxiliary engine drives are old fashioned as they create payload limitations and add to the maintenance cost.
With high pressure water capacities ranging from 300 to 500 litres per minute, it is vital to select the correct hose reel combination to aid the operator. Modern manufacturers now offer multiple hose reels options to suit various applications. In the main, these reels come in single or dual format, are hydraulically powered, fully slewable and speed regulated. Radio Remote controls have brought a new dimension of safety to operating these machines. Up to 32 individual functions can be activated, changed or stopped.
Finally, jet nozzles and root cutting devices need to be suited for recycled water. A conventional hardened nozzle will only last for minutes on recycled water. Ceramic inserts and special sealed rotary units need to be used to obtain an acceptable service life from these devices.