Since 6 September 2023, the mandatory content of a public works design in Portugal has been set by Ordinance 255\/2023 \u2014 which replaced the 2008 one \u2014 and it has a section devoted to wastewater drainage and treatment. Phase by phase, it states what the designer must deliver, from the base design to the detailed design.<\/p>\r\n\r\n\r\n\r\n
You would expect that to be enough. It is not, for a simple reason: the ordinance says what<\/strong>, and never says how much, measured how, or from what data<\/strong>. That is the tender specification \u2014 and it belongs to whoever is buying.<\/p>\r\n\r\n\r\n\r\n We read five sets of tender specifications for designs on existing treatment plants, contracted between 2021 and 2026, from \u20ac20,000 to \u20ac234,000, by five different entities \u2014 two of them in the same group, sharing the same boilerplate word for word. Two of the five specify no technical content at all: some twenty thousand characters each, and not one requirement on flow, phasing, pre-treatment, energy or effluent destination. They refer to the legislation. And legislation, on its own, returns the minimum.<\/p>\r\n\r\n\r\n\r\n There are five things you only get if you write them down.<\/p>\r\n\r\n\r\n\r\n The ordinance is clear: the preliminary programme is \u00abo documento fornecido pelo dono da obra ao projetista\u00bb \u2014 the document supplied by the client to the designer. For a treatment plant it has its own elements (article 151): the design horizon, the current state of the area served, the existing infrastructure, the industries connected to the network and their discharges, and the receiving water body \u2014 \u00abcaudais de estiagem e caracter\u00edsticas bioqu\u00edmicas\u00bb, low-flow rates and biochemical characteristics, included.<\/p>\r\n\r\n\r\n\r\n When the client does not supply them, the designer assumes them. And assumes what is reasonable, not what is true: the factory that discharges at night, the stream that runs dry in August. The preliminary programme is not paperwork; it is the only phase of the design written by someone who knows the plant.<\/p>\r\n\r\n\r\n\r\n The question to ask:<\/strong> who writes the preliminary programme \u2014 and from which operating records?<\/p>\r\n\r\n\r\n\r\n The base design calls for \u00abcapita\u00e7\u00f5es de consumo de \u00e1gua e coeficiente de aflu\u00eancia \u00e0 rede\u00bb \u2014 per-capita water consumption and network inflow coefficient \u2014 and the \u00abcrit\u00e9rios adotados\u00bb, the criteria adopted, for infiltration and stormwater (article 152). Criteria, not measurements. The law allows calculation.<\/p>\r\n\r\n\r\n\r\n Only the tender specification can require a flow measurement campaign in dry and wet weather before anything is sized, and state whether it sits in the design price or is the client’s own cost. Of the five specifications we read, two do not use the word flow once.<\/p>\r\n\r\n\r\n\r\n The question to ask:<\/strong> does the specification require measured flows, or accept flows calculated from population?<\/p>\r\n\r\n\r\n\r\n Two of the five specifications require that \u00abo cocontratante dever\u00e1 optar, fundamentadamente, por solu\u00e7\u00f5es de engenharia que minimizem o consumo de energia potenciando a efici\u00eancia energ\u00e9tica\u00bb \u2014 that the contractor shall opt, with justification, for engineering solutions that minimise energy consumption while enhancing energy efficiency. The intent is right \u2014 and it cannot be verified. “Minimise” has no number.<\/p>\r\n\r\n\r\n\r\n The ordinance goes further than those specifications: the detailed design must carry \u00abconsumos espec\u00edficos\u00bb per unit process and the \u00abbalan\u00e7o energ\u00e9tico da instala\u00e7\u00e3o\u00bb, the plant’s energy balance (article 155), along with operating costs across the design horizon \u2014 energy, reagents, sludge, maintenance. What is left is what the specification adds: the units (kWh per cubic metre treated and per kilogram of COD removed), the reference case (the plant as it stands today) and the flow scenarios the figure is computed under. With that, two bids can be compared. Without it, adjectives are compared.<\/p>\r\n\r\n\r\n\r\n The question to ask:<\/strong> does the specification state in what units, and against what reference, the energy balance is presented?<\/p>\r\n\r\n\r\n\r\n In a refurbishment with the plant running, the ordinance requires a \u00abdescri\u00e7\u00e3o detalhada do modo de constru\u00e7\u00e3o especificando as v\u00e1rias fases de execu\u00e7\u00e3o, bem como os principais impactes no modo de explora\u00e7\u00e3o\u00bb \u2014 a detailed description of the construction method specifying the execution phases and the main impacts on operation (article 155) \u2014 and, as early as the preliminary design, \u00abtestes, ensaios e inspe\u00e7\u00f5es\u00bb, tests, trials and inspections of the existing structures and equipment (article 154).<\/p>\r\n\r\n\r\n\r\n No designer does this without entering the plant, reading the operating records and talking to the people who run it. The specification is where that access is secured \u2014 site visits, telemetry data, breakdown history \u2014 and where it is decided what gets tested before it is decided what gets replaced.<\/p>\r\n\r\n\r\n\r\n The question to ask:<\/strong> does the specification provide for access to the plant and its records, and state which tests on the existing works are included?<\/p>\r\n\r\n\r\n\r\n The ordinance defines design review as \u00aban\u00e1lise cr\u00edtica do projeto […] por outrem que n\u00e3o o projetista\u00bb \u2014 a critical analysis of the design by someone other than the designer. Among the 145 study and design contracts mentioning a treatment plant, awarded between 2021 and July 2026, nine are design reviews \u2014 and all of them from 2024, 2025 and 2026. It is few, and it is recent.<\/p>\r\n\r\n\r\n\r\n A review costs a fraction of the design and catches, before the works tender, what otherwise turns up as variations. It need not be a separate contract: it can be a clause in the specification \u2014 who reviews, at what phase, with what turnaround.<\/p>\r\n\r\n\r\n\r\n The question to ask:<\/strong> does the specification set out who reviews the design, and when?<\/p>\r\n\r\n\r\n None of these five requirements is against the designer. A serious designer meets them anyway \u2014 and prefers a specification that writes them down, because that is what separates them from those who do not. What the specification does is stop the difference between the two from being settled on price.<\/p>\r\n\r\n\r\n\r\n The ordinance sets the minimum. The specification sets what you receive.<\/p>\r\n\r\n\r\n IdroAM Water Engineering designs and reviews wastewater treatment plant projects. If you are preparing tender specifications for a design, talk to us.<\/em><\/p>\r\n","protected":false},"excerpt":{"rendered":" Ordinance 255\/2023 says what the designer delivers. It never says how much, measured how, or from what data. That is the tender specification \u2014 and it belongs to whoever is buying.<\/p>\n","protected":false},"author":7,"featured_media":1710,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[29],"tags":[],"class_list":["post-1700","post","type-post","status-publish","format-standard","has-post-thumbnail","category-technical-articles"],"yoast_head":"\n1. The preliminary programme \u2014 which is yours, not the designer’s<\/h2>\r\n\r\n\r\n\r\n
2. Measured flows, and who pays for the measuring<\/h2>\r\n\r\n\r\n\r\n
3. An energy balance with units, not with adjectives<\/h2>\r\n\r\n\r\n\r\n
4. Phasing with the plant in service \u2014 and access to it<\/h2>\r\n\r\n\r\n\r\n
5. Who reviews the design<\/h2>\r\n\r\n\r\n\r\n
\r\n\r\n\r\nThe point<\/h2>\r\n\r\n\r\n\r\n
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