CASE STUDIES
drain TRADER
70 not out! The original Chopper
Pump is here to stay
In 1950, Landia’s Christian Oelgaard invented the Chopper Pump. Seventy years on, how is it that this piece of equipment has not only stayed the course, but now seems more relevant than ever? The design principle remains unchanged since day one; a unique external cutting (knife) system at the inlet that stops the Landia Chopper Pump from becoming blocked. Originally created to chop strawin liquid animal manure that often causes stoppages and problems, the Landia Chopper Pump has since been installedworldwide – typically in those hard-to-handle applications where solids bring less sturdier pumps to a halt. One of those very successful overseas installations has been for the aeration andwastewater system at a major poultry processor in Saudi Arabia.With the addition of a venturi nozzle, the Landia Chopper Pump becomes the AirJet aerator - serving an effluent treatment plant utilising MBR technology that treatswastewater from the poultry and rendering plants (c. 6,000m3/day).Made with cast iron casings, plus stainless-steel impellers and shafts, the AirJets keepwastewater aerated and mixed in two 800m3 balance tanks prior to Dissolved Air Flotation (DAF). In the two 130m3 DAF sludge tanks, AirJets keep the tanks’contents fresh and homogenised prior to further treatment by a tricanter centrifuge. AirJets are also utilised for two 150m3 biological sludge tanks, aerating and mixing to provide homogenous composition to sludge dewatering equipment. Furthermore, AirJets are also installed in anoxic tanks for mixing purposes, aswell as in the sewage treatment plant. The upgrade for this processor in Saudi has been managed by MSA Environmental, a leading independent environmental consultancy based inWiltshire that operates within the food, drink and dairy sectors.
‘Robust and reliable’
Jerad O’Pray, Director at MSA Environmental, commented:“Not for the first time, the Landia Chopper Pump (here in the formof its AirJet model) has delivered very good performance, aswell being extremely robust and reliable. To suit the size of the large balance tanks (2 x 800m3) at the poultry processor,we specified 18.5 kW AirJets as part of our design, whilst 7.5kW motorswere best suited elsewhere throughout the plant”. He added:“With our detailed engineering and process design experiencewe always look to provide our clients with the best possible solutions for the long-term. Landia equipment is a proven piece of kit thatwe have no hesitation in specifying. Importantly,we always get good back-up from Landia too. They are always keen to hear that their Chopper Pumps areworkingwell and that the customer is happy”. He continued:“We have also used these units on overseas projects in
32 drain TRADER | August 2020 |
www.draintraderltd.com
hot climates to handle aeration, anoxic tanks and sewage. There have been no problems, despite ambient temperatures that are consistently above 40 deg C. The AirJets also help reduce odour issues by keeping the tanks fresh during the near 24/7 operation”. Much closer to home in Cornwall, Landia AirJetswere also introduced during the upgrade of Dairy Crest’swastewater treatment process in Davidstow, home to the much-loved cheddar. Initially, four stainless steel AirJetswere installed in balance tanks that required thorough mixing.
‘Long lasting equipment with low maintenance’
SimonMerchant,Manager for theWastewater Treatment Plant (WwTP) said: “We first rented a submersible Landia AirJet to put it through its paces and help minimise odour potential in our balancing tank. It proved itself for being robust, reliable and effective.We needed top quality, long lasting equipment with lowmaintenance. Some major modifications to our balance tankwere undertaken, which included the addition of externally-mounted Landia AirJet units. These have been operational for four months, and the early signs are very positive with improved dissolved oxygen levels, reduced H2S levels – and much lower noise levels. In addition, they have proved to be very
Landia’s ChristianOelgaard invented the Chopper Pump in 1950
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