As councils and industrial waste processors count the cost of damage to their water and wastewater plants resulting from Australasia’s record rainfalls, a new threat is emerging from the rivers of mud now threatening to clog their systems and environmental safeguards.
“The rain itself is just the start of the challenges,” says one of Australia and New Zealand’s most experienced water and wastewater authorities, Michael Bambridge. “Even as the rains eventually abate, local councils, food and industrial users will face major challenges keeping out the dirt and grit from the oceans of mud that contaminate both potable water and wastewater processes.”
“With continuing floods, muddy water will be the next big challenge as we increase our resilience to the effects of climate change,” says Bambridge, who is Managing Director of CST Wastewater Solutions, a company which has completed hundreds of municipal and industrial plants and upgrades in both Australia and New Zealand.
Bambridge says front-line defences against the influx of mud into water and wastewater processes will include better, more efficient, and durable primary screening and grit removal processes.
“These are the front door to water and wastewater treatment plants. If you leave them open, every process downstream is immediately compromised. If secondary processing is to achieve the environmental and water quality outputs the plants are designed for, first you have to ensure that it gets optimum protection from dirt and debris entering with increasingly wide ranges of surges in demand imposed upon it,” says Bambridge.
One of his company’s first responses to the emerging problems – and to the shortages of maintenance engineers in many smaller water and wastewater plants – is to begin full local manufacture of the first stage of robust low-maintenance primary processing technology, including compact rotary drum screens engineered from stainless steel to withstands the extremes of local operation.
A second major response to local conditions is the introduction of Smith and Loveless Invorsor to remove and settle grit and particles to 75 micron. Smith and Loveless’ PISTA technology is available to Australian councils and industrial users through CST Wastewater Solutions, and to NZ customers directly through Smith and Loveless.
“One of the major advantages of the PISTA® grit removal technology in local conditions, is its ability to function over a wide turndown range, a flow variation which occurs often where localities are subject to both to drought and flooding,” says Bambridge.
Turndown is the range over which a system can fully perform. It is an equation that is particularly important in this land of drought and flooding rains, he says.
“In addition to its outstanding overall performance, PISTA Invorsor® systems can even remove grit down to 75 microns, which is fine silt. This gives it high capability to remove dirt and grit solids from flooded waterways,” he says.
Smith and Loveless’ performance testing of the system showcases actual PISTA® hydraulic forced vortex systems in the US and globally.
The technology is designed to benefit utilities and industrial users in flood-prone regions, as well as industrial users.
“CST’s high performance inlet screening and S&L grit removal technology is proven in service under local conditions to help eliminate the build-up of grit in downstream aeration basins and sludge digesters, reducing damage to downstream equipment from abrasion,” says Mr Bambridge.
The combination enhances wastewater treatment plant – and potentially water treatment plant – reliability while reducing the likelihood of flooding and the associated hazardous issues involved in unclogging systems. It also helps to prevent environmental spills from blocked and flooded systems.
“Environmental spills can be a major source of waterway pollution, with often foul-smelling and harmful effluent from water and wastewater systems flowing into groundwater, local waterways, and marine environments. This blocking and overflow is an expensive, dirty, and thankless task to remedy, with ongoing OH&S risks to operations staff as well as harm to local environments. Obviously, prevention is better than cure.”
