Improving efficiency of the Carioba treatment plant in Americana, São Paulo (SP), Brazil
Within the scope of the research project “Decentralized water supply and sewage disposal in conjunction with the generation of energy and material for the region of Piracicaba by taking hygiene aspects into consideration” funded by the German Federal Ministry of Education and Research (BMBF), a cooperation agreement was signed in April 2005 together with the Departamento de Água e Esgoto (DAE) and the Americana mayor’s office. One of the aims of the agreement was the evaluation of the Carioba sewage plant, one of the first sewage plants in the region, which was commissioned in the mid-eighties of the last century.
We opted for a step-by-step approach to assess the sewage plant. Apart from analysis of the operating log, measurements were carried out alongside the sewage plant. In addition we evaluated a trial for which DAE Americana had commissioned a Brazilian engineering office. They proposed the almost complete re-construction of the sewage plant; the original plant was only to be run with 10 % of accruing sewage water. This would incur extremely high costs. The proposal of the Fraunhofer IGB to integrate the existing sewage plant into a new concept thus achieving a considerable cost reduction was therefore accepted with great pleasure.
New concept and pilot plant
For better monitoring of the operating results of the sewage plant our project partner MAXX GmbH developed two automatic samplers as prototypes for tropical use (Fig. 1). The training of the operational staff by way of seminars lasting several days was a further component of the measures taken. Finally, a pilot plant for advanced wastewater treatment was installed at DAE Americana (Fig. 2). The pilot plant is operated as a sequencing-batch-reactor (SBR) with the original wastewater from the feed for the Carioba sewage plant with the aim of determining the required design documents. To do so it was equipped with on-line measuring technology for the relevant wastewater parameters.
Good degradation of sewage in the pilot plant
The investigations showed that the existing poor degree of degradation by the Carioba sewage plant was not caused by the negative effect of the industrial effluents as had been assumed by the operators, but rather by the overload of some parts of the treatment plant and by additional operating problems. The pilot plant is able to breakdown the effluents: the removal of nitrogen and phosphorus is sufficient and the degree of efficiency with a view to BOD5 is above 95 %. Figure 3 shows the operating results of the pilot plant based on the parameters COD, NH4-N, NO3-N and dissolved oxygen (DO).
The work carried out and the approaches used were submitted to the Consórcio das Bacias dos Rios Piracicaba, Capivari e Jundiaí by our partner DAE Americana for this year’s Prêmio Açao pela Água competition and awarded a prize as one of the five finalists.
Within the next few years the sewage plant will be extended according to the proposals of the Fraunhofer IGB – it will then be one of Brazil’s first (sewage) plants with advanced wastewater treatment.
The project “Decentralized water supply and sewage disposal in conjunction with the generation of energy and material for the region of Piracicaba by taking hygiene aspects into consideration” was funded by the German Federal Ministry of Education and Research (BMBF).
MAXX Mess- und Probenahmetechnik GmbH, Rangendingen
Departamento de Água e Esgoto (DAE) Americana, São Paulo (SP), Brazil