Good afternoon, everyone, and thank you for joining us. We had a strong start to the year. The revenue, EBITDA, order intake, and backlog all delivered a growth compared to last year. The revenue growth of 42% is coming from the Cambi Group segment at the back of a strong opening backlog and also the awards during the quarter. EBITDA margin is in line with or at the same level as last year. It's reflecting the changes in revenue mix compared to last year, where we had fewer ongoing high-margin upgrade projects this year. We also had higher payroll costs and also DBO investments made to expand in sales marketing and then growing our pipeline. The order intake growth and backlog growth, underlying growth in these two were just shy of 19% and 66% respectively, using the constant currency and adjusting for the strengthening of the Norwegian krone.
If you look at the order intakes in the quarter, overall, we delivered a book-to-bill of 1.4. We signed four main contracts in the quarter. Our first contract in South Africa for the delivery of a B2 system. It's an industrial customer, and for the customer, this is a full-scale pilot plant, and if successful, may lead to higher scope and larger systems to be delivered. It's a fast-track delivery where we expect to ship it this quarter. We also signed a contract for an upgrade of a plant that's been in operation since 2008 for the delivery of a new digester. The third project was a contract for a B2 plant to Southern Water for their Goddards Green plant. The main drivers in this project were to handle the odour issues at the plant and also to ensure a stable cake.
In the U.S., we signed our first contract in the state of Missouri for the delivery of a B6 plant, and it's the eighth state with a Cambi-reference plant in addition to Washington, D.C., and following on to the momentum we had last year. We signed two new projects and the first one in North Carolina. It's following the path that we expect in the U.S. with a growing pipeline and Cambi being the only THP provider with a reference plant in the market. Looking at the backlog, as you can see, the lion's share is in the Cambi Group segment. The Cambi Invest backlog is coming from the upstream contracts in Gunnebo.
The distribution that you can see here, we have expected turnover from backlog of NOK 229 million for the rest of this year, is based on assumptions on project execution, the percentage of completion on our ongoing projects, as well as the expected volume from the upstream contracts in Gunnebo. It's applying the closing FX at the end of the first quarter, and the uncertainty in the distribution is mainly linked to these two assumptions. If I move to the segments and segment performance and then take a look at the Cambi Group first. We did see a strong revenue growth in the equipment sub-segment. As I mentioned, it was at the back of the opening backlog and as well as the new awards during the quarter. In the services sub-segment, as mentioned, the drop in upgrade projects, we saw a decline of 33%.
The rest of the revenue sources in the services delivered in line with last year, being the spare parts sales to support during annual shutdowns and the consultancy. For the EBITDA, we ended as expected, adjusted for the non-recurring cost related to the listing on Euronext Growth of NOK 1.8 million. As already talked about, the book-to-bill was strong within this segment. It was 1.6, with an underlying growth of 45% compared to last year. Within Cambi Invest, we expected a lower turnover than last year. Last year, it was a mild winter in Norway. This year we did not only have a mild winter, but also periods with very cold weather that's affected the production costs and thereby also affecting the EBITDA margin that we delivered in the segment. Overall, we exceeded expectations in the first quarter within Cambi Invest.
When it comes to order intake, there were no major awards in the market in the quarter, as opposed to last year where there were several contracts awarded in the market. On the balance sheet, we have a very solid financial position following the private placement in the first quarter. The other elements in the balance sheet is related to mostly ongoing projects, and customer payments are on track. In the balance sheet, as you can see here, we have financed the U.S. projects as we have talked about before, and the working capital facility on the WSSC and the Raleigh project. That's the main changes in under liabilities in the quarter. If you look at the recent development and also outlook, I'm very pleased to see the momentum that we have, and we're continuing from last year.
We see a growing interest for our solutions, not only in the equipment sub-segment, but also in the DBO projects. We see customers focusing more and more on other KPIs than the traditional financial drivers behind a project. We talked about the environmental impact and the carbon footprint analysis included in more tenders than before, but also the recent development in, for example, France and Spain, where the focus around hygienization has increased following the COVID-19 pandemic. That's led to more leads in our pipeline, which is promising. The tender activity is high in the first quarter. The number of price submissions, both in price indications, budget quotes, and formal quotes, were up 50% compared to last year. In the marketing efforts that we have, the focus that we have in sales and marketing, as we talked about, this being the main bottleneck for Cambi to grow.
We see a higher stakeholder engagement, more participants in our webinars, both potential customers and also consultants and other stakeholders, and also the engagement following these webinars. We have so far, in the second quarter, signed two new contracts, both in Poland. We have signed an LOI with Charlotte Water in North Carolina in USA. For the outlook, we have remained at the same level as previously communicated, with a turnover range between NOK 480 million and NOK 510 million. At the EBITDA range, we maintain that as well, but we expect to be in the lower end of the range when closing the year. That was the end of my presentation. If you have any questions, please don't hesitate to either give me a call or send questions to the investor email, and we'll answer those questions as soon as we can.