3,000 manholes to be sealed to stop illegal dumping inside Malta’s sewers

Illegal waste like cow’s carcasses and pigs’ heads gets dumped inside Malta’s sewers: 3,000 manholes around the island will have to be sealed shut to stop the abusive practice

Pig manure can become a very costly problem for Malta
Pig manure can become a very costly problem for Malta

A cow’s carcass, pigs’ heads, ‘fatbergs’ of congealed oil discharge, dozens of Sea Bass bred in unlicensed aquaculture operations... all of these have been illegally dumped inside Maltese sewers. 

But the damage such illegal waste is causing to the island’s sewage treatment plants, is about to force through a drastic plan: sealing off 3,000 manholes around the island.

It will be the only way to prevent the industrial and agricultural waste from entering the sewers, something that inevitably leads to the shutdown of the sewage treatment plants.

And it has already been carried out in Gozo, where manholes used for illegal disposal of animal waste were sealed shut, to prevent the €16 million treatment plant there from being brought to a halt. 

Sewage treatment plants are now producing second-class, or ‘new’ water: an ultra-filtrated water from domestic sewage that gets used for agricultural irrigation.

New water has given Maltese farmers a stable supply of low salinity water – unlike groundwater reserves – and has even improved crops by giving them better shelf life. Some farmers have reported getting two crops a year because new water does not have any negative impact on the fertility of the soil. 

“Unfortunately, the illegal waste being dumped in the sewers instantly brings to a stop the treatment plants. Once the system detects all those nitrates in the sewage, the plant shuts down. And this means that domestic sewage has to be bypassed and dumped out at sea until the plant is put back into operation,” a government source said.

The problem occurred again last week when the Ta’ Barkat plant in Xgħajra had to be shut down because of farm animal excrement that was dumped illegally into the public sewer.

The treatment plants take in over 60,000 cubic metres of raw sewage every day in Malta and Gozo. But these plants, so essential for the delivery of new water to Maltese agriculture, are threatened by solid waste and animal carcasses dumped by animal breeders or industrial operators refusing to pay the full cost for the proper disposal of their waste. 

Malta’s problem with illegal dumping from farm waste, or slurry, inside the sewers started 10 years ago, when EU rules on nitrates introduced strict limits on the spreading of manure in fields, which naturally leads to increased nitrates in soil. 

While a number of farms, mainly those harbouring cattle, have developed the ability to store the manure during periods when it cannot be applied to fields, other sectors have been less effective. Spreading untreated manure on agricultural land is still common practice in Gozo, for example – a practice that raises the risk of food-borne infection being spread on crops. 

READ MORE Hogs’ manure causing multi-million headache

One government study in 2016 identified pig slurry as being simply disposed of in the sewerage system. But instead of using designated sewage spots regulated by the Water Services Corporation, “due to the cost of transport and for convenience sake, farmers use other, generally, inappropriate discharge points along the sewerage network. The waste is generally not processed through a solids separator prior to disposal and this can result in blockages of the sewage collection network, also affecting the wastewater treatment plant operation.” 

As a result, the treatment operation gets compromised, leading to the shutdown of the treatment facilities. The only saving grace is that the plant is able to return to normal operation within 24 hours, but that necessitates the discharge of raw sewage at sea.

Otherwise, it would take two to three weeks for the plant to recover until it reaches normal treatment parameters, if it is not shut down.

“Sealing the manholes will put a stop to the illegality going on right now,” the source said. “There is still more to be done, which is enforcing a legal way of disposing of this waste – but unless drastic action is taken, illegal dumping will keep threatening sewage treatment plants.”

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