A work I had before

I was working in Food and Veterinary Service as a laboratory technician at Water laboratory. For many years I was doing the same job and it always was challenging. Workers in the lab have always to be aware what they do, what glassware to use and what method to use for particular analyse. Work in the lab is a team work. People have always to support good relations to have productive results. I was the youngest worker in my team. I have educated and intelligent people around me. Every day I learned something new not only for work but also for my life. I realy liked my previous job.

A The work I had before (or My Previous Job)

I was working in the Food and Veterinary Service as a laboratory technician at a water laboratory. For many years I was doing the same job but it always was challenging. Workers in the lab have always have to be aware of what they are doing, what glassware to use and what method to use for a particular analysis. Work in the lab is team work. People have always to support good relations between each other to get on well together in order to have productive results at work. I was the youngest in my team. I have had educated and intelligent people around me. Every day I learned something new not only for work but also for life*. I realy liked my previous job.

* This is fine. You could also say:

 ...not only about work, but also about life.

A work I had before

I was working in the Food and Veterinary Service as a laboratory technician at the Water laboratory. While working there For many years I was doing the same job and it was always was challenging. Workers in the lab have always have to be aware of what they do, what glassware to use and what method to use for a particular analyse analysis. Work in the lab is a team work. People have always have to support good relations to have get productive results. I was the youngest worker in my team. I have had well educated and intelligent people around me. Every day I learned something new, not only for work related, but also for my life on the personal level. I realy really liked my previous job.

Good work!