icalidad

The residual water the depurated and the mud that arrives at Emarsa are subject to diary and weekly tests in the Pinedo's Waterworks laboratory. The objective is check what the different phases of the depuration process work in a correct way and what the mood and the purified water have the quality enough to arrive at the crop fields as much as the compost and irrigation water at the sea and the "Albufera" with guarantees.

It's 8.00 o'clock and the collection of dirty water samples that get through the collectors, the one that leaves the primary decanter and the clarifier (already purified), as well as mud coming from the Primary Treatment (liquid state) of the Ventilation Barrel, Biological Treatment, and the named "Torta" (dehydrated mud that is sent to the crop fields to be used as fertilizer) begins.

But this collection of samples isn't the only that is made during the day. For 24 hours and hourly, water of the different phases is mixed to obtain what it is known as "an integrated sample", that is the one that is tested to get a representative result, because the pollution load is different throughout the day.

In a litre of "integrated mixture", it is observed for sixty minutes the way in which the dissolved particles and the particles in suspension that are in the water fall due to the gravity into the bottom of the cone. This test is made to see the amount of mud that is eliminated in the Movement (Primary Treatment).

The PH, the conductivity, the suspended solids , the DBO5, are the studied parameters in the mixture of the water among other. The PH must be neutral so that the Biological Treatment is not altered. The Conductivity measures the dissolved salts in the water and if it is or not of urban origin. The higher percentage of salts more pollution there is. The industrial water has a high load of salts. The DBO5 or Biological Oxygen Demand, indicates the necessary oxygen for the oxidation of the biodegradable organic material which is carried out by the micro- organisms present in the sample. These micro-organisms consume the oxygen since they are alive beings and are fed on the organic material.

Also the DQO or Biological Oxygen Demand is tested. It indicates the necessary oxygen to rust the organic material in a chemical way. The chemical oxidation is more complete than the bacterial degradation (DBO5). It is not able to differentiate between biodegradable substances and non-biodegradable organics. In the say way the chlorides (chlorine) and the sediments, like sand, are controlled.

The mud of the four Biological Reactors and the "Torta" are tested every day. These tests are focused on measuring the speed of mud sedimentation and they are obtained in an approximated time of 30 minutes. In other tests the mud concentration is studied within the reactor, important aspect to keep a balance between the residual water and the mud, as well as the quantity of oxygen that there is in the ventilation barrel, so that the bacillus are in a suitable environment and can degrade the organic material in a suitable way. Furthermore, it is observed by the microscope the nature of the bacillus that live within the reactor.

With "Torta" or remainder dry test, it is possible to know the quantity of organic material that there is left in the mud, since an excess is detrimental for the crops that are fertilized with the mud. The nutrients (nourishment for the plants) and the volatile character of the "Torta" are observed as well.

Nitrogen, phosphorous, nitrates are nutrients and vitamins that are contained in the depurated water that exits of Emarsa. It is indispensable to know the accurate quantities of these substances that there are left in the water after the depuration process.

A high quantity of this substances in the water, which is sent to the crops fields for the irrigation, results really beneficial for the plants but not for the "Albufera" and vice-versa. It is very important to take the samples the same day the test is going to do so that the results are worthy.

The fats prevent the reception of the oxygen for the germs. For this reason, it is important to eliminate the greater quantity of them. In most of the occasions, the facts can't be reduced in their totality. The fats are tested in all the phases of the depuration process to determine how many fats are dissolved in the entry water, which is got by the collectors, and how many fats have been eliminated.

The digesters play a fundamental role to assure what the mud, which is going to be used like compost of the crops, is free of pathogen agents. Because of this, the mud is tested weekly to check that the digestion has been correct. Also, it is controlled the sulphuric gas, since, it is highly corrosive.

The Waterworks receives external liquids that arrive at the plant in cisterns. In order to avoid these effluents can modify the purification process, since they could contain dangerous substances because of their unknown nature, the samples are taken as much the entrance water as of mud that happens through the digesters. In these tests an special attention are paid to the load of the heavy metal like lead, cadmium, zinc, chromium and nickel, among others. The toxicity and the DQO are the main parameters that are measured in this case. All the results are written down diary in a parts which the monthly average is obtained with. Also, the monthly volumes of entrance and of exit are calculated.