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Wet wipes are causing big problems for the sewage treatment system

A tangle of wet wipes removed  from the downpipe of a block of  apartments.
A tangle of wet wipes removed from the downpipe of a block of apartments. / SUR
  • Every month in Malaga province 400 tonnes of rubbish have to be removed from the pipes because it causes blockages and sewage overflows

Cotton buds, tampons, condoms, bits of food, used oil, nappies... people throw a wide variety of things down the lavatory, but what is causing the biggest headaches for the people who look after our sewage pipes are wet wipes; originally designed to be used for babies in recent years they have commonly been used by the whole family.

There have been numerous campaigns to raise awareness of this problem, but they have had little result because many still use the lavatory as a rubbish bin without realising, or maybe not caring, that these products do not disappear by magic when the chain is pulled.

Quite the contrary, in fact: they accumulate into an enormous mass which obstructs the downpipes of blocks of apartments and, once in the outside pipes, the manholes, collectors and pumping and treatment systems as well. They cause the equipment to break down on a regular basis, and when that happens waste ends up flowing into rivers, streams or directly into the sea through the spillways. The problem is especially serious on rainy days because in most towns the rainwater and waste use the same pipes and these end up overflowing.

The problem of cotton buds and other personal hygiene products is nothing new. In fact, the sanitation companies have learned to live with them by introducing new equipment. However, what the system can't cope with, and what causes the most frequent problems, is the daily avalanche of wet wipes. It can't deal with them because they are made with textile fibres which form a skein, and this is impossible to undo; as well as blocking the pipes they also break the equipment. Wet wipes are now used in many homes, and

families are misled by manufacturers who claim they are biodegradable. Some even say on the label that they can be disposed of down the lavatory with no problem.

Slow decomposition

Technically, yes, they do decompose when they come into contact with the water but it takes about two weeks for them to do so, while ordinary toilet paper degrades in a matter of hours. This was demonstrated recently in a laboratory test carried out by the Emasa municipal water company in Malaga: it subjected wet wipes, moist toilet paper and conventional toilet paper to constant movement and compared how long it took them to decompose.

Bearing in mind that it takes up to 48 hours from the time the cistern is flushed to the arrival of the waste at the treatment plant, it is obvious that this is not long enough for the material to degrade. As a result, in the pumping and treatment stations in Malaga province an average of 400 tonnes of rubbish has to be removed every month; of this more than 90 per cent contains wet wipes.

In addition to this, some wet wipes disposed of down the toilet never reach the plant; they accumulate in the pipes and when it rains the waste becomes tangled up in the drains, collectors and spillways. Everyone knows what happens then: unpleasant smells and pools of sewage coming from the drains and flowing into the rivers, streams or directly into the sea, because the equipment just can't cope.

“It doesn't matter how much we invest in technology to try to filter wet wipes, or how many awareness campaigns are carried out, while they continue to be sold as if they were biodegradable and people keep throwing them down the toilet there is nothing we can do about it,” says Emasa's director of Maintenance and Treatment, Concepción Fernández Cotrina, resignedly.

She says wet wipes have become the most serious problem for the system, even the ones which are degradable, because when they decompose their particles are scattered about and they create microplastics which end up in the sea with no type of filter.

“We're not trying to stop them being sold, we just want the people who use them to throw them into the rubbish bin, not down the lavatory,” says Concepción, as she shows us how in just 24 hours a container which can hold eight cubic metres has been filled with wet wipes removed from the Guadalhorce treatment plant.

“This is a normal day. When it rains, it is much worse. One container after another,” says an employee, briefly removing the mask he has to wear because of the stench from the mass of wipes mixed with waste water that have to be removed manually from the machinery.

This is a global problem, and companies from 25 countries have now set up the International Group of Water Service Operators to establish a set of conditions with which products must comply if they are to be labelled 'disposable down the lavatory'. However, the magnitude of the problem is multiplied in places like Malaga, where it rarely rains and, when it does, it is torrential, so that the wet wipes which for months have remained sedimented in the pipes are pushed to the pumping stations (which in turn push the waste water to the treatment plants), causing problems in pumps and filters.

“When there is a blockage the machine stops operating, the water level rises and the drains overflow into the streets, streams or onto the beach,” explains Jorge Gil, head of the collector drains department at the Acosol water company, which is part of the Mancomunidad de Municipios of the western Costa del Sol.

Apart from the environmental impact, he emphasises the “appalling” cost of preventive maintenance work, investment in new equipment and constant repairs, especially because on days when the flow increases no equipment could deal with it.

Extra cost

It is not easy to put a figure on this extra pressure on human and technical resources, not to mention the environmental damage caused, but the AEAS Spanish Water Supply and Sewage Association calculates that when people throw rubbish down the toilet it increases the treatment costs by between ten and 18 per cent, which is about 200 million euros a year. Although this cost is initially met by the companies, it is eventually paid for by consumers through their water bills.

Sources at Axaragua, the company which handles sewage treatment in the main coastal towns in the Axarquía region, estimate that cleaning the pumps and pipes, removing and treating the rubbish, maintaining and improving equipment and repairing breakdowns puts the cost of dealing with the wet wipes at more than 400,000 euros a year.

“People don't realise the problems that are caused when they don't dispose of wet wipes properly, because when they put them down the lavatory it causes blockages in the whole network, starting with the domestic pipes and then continuing in the public ones,” says Antolín de Benito, of Axaragua.

As Jorge Gil also stresses, “the fact that when you throw a wet wipe down the lavatory it disappears, does not mean that the person who flushes bears no responsibility for the damage they have caused.”

tonnes of rubbish a month are removed from the pumping and treatment plants in the province, and more than 90 per cent are wet wipes. In addition to this figure, others have to be removed from apartment blocks by specialist companies, and some end up in the pipes and come out through the spillways when the pipes cannot cope with the increased flow resulting from rainfall or breakdowns.

is the extra cost of maintenance and repairs which are necessary due to the presence of wet wipes in the network, according to the Spanish Association of Water Supplies and Sanitation (AEAS). Nationally, the figure is around 200 million euros.