Anaerobic treatment as a wastewater treatment process with low
consumption of energy and low sludge production
Energy consumption reduction is, currently, one of the main goals in the wastewater treatment system of the Murcia Region. Pollutant removal efficiencies are really high (99 % is the average efficiency in BOD5) in the most of WWTPs and now we are looking for treatment systems more eco-efficient. In regions with a warm temperature, anaerobic treatment can become a good system to remove a lot of organic matter of the wastewater with a very low consumption of energy, due to characteristics of anaerobic processes and, moreover, the production of sludge is low. Unfortunately the efficiencies you can get are depending on temperature. Regarding temperatures of Murcia Region, COD removal efficiencies of 50 % are being got in winter and 75 % at least in summer. Moreover the sludge production is really low compared with traditional systems. Of course, we´ll need a second step, usually with conventional treatment processes to get very good efficiencies, but the costs will be much lower because we have removed a lot of pollution before.
We decide to set this technology after several tests on pilot plants in different WWTPs in the region. Then, taking advantage of a LIFE project (RAMSES), a large -scale anaerobic reactor was built in the WWTP of Blanca, using an empty tank we had there and we are working with this system for more than three years. After this treatment we have an extended aeration system to get the highest efficiencies.
The water treated is used in agricultural activity
Several pilot plants have been tested before the decision to implement this technology. Also, the contribution of LIFE funds have been very appreciated, as well as the contribution of ACCIONA, the operator of Blanca Waste Water Treatment Plant (WWTP)
Evidence of success
According to the results, we are getting good efficiencies of COD removal. Also, the sludge reduction is very high. Another advantage of the system is related to the stability of the wastewater treatment process and the extinction of filamentous bacteria, which is a strong enemy of the plant operators. The improvement of energy consumption wasn´t as high as expected, due to specific characteristics of influent wastewater, as we´ll explain afterwards.
Dealing this technology in real conditions. The main problem was the water features, because a high concentration of sulfate in It, making the sulfate-rreductor bacteria compete with methanogenic bacteria and one of the advantages of the process, production of methane in the biogas, is inhibited.
Potential for learning or transfer
This process could be installed in regions with warm temperatures all the year and could be an excellent energy saving process. Even the system could be more interesting in places with high pollution loads in the wastewater, mainly due to industrial discharges.
Through the information of the scientific articles or information of LIFE RAMSES project or ESAMUR presentations, this technology could be spread to other interested regions.
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