diff -r eaadfa988db4 -r 7fcb9d12e181 server/src/main/java/org/iri_research/renkan/controller/RenkanController.java
--- a/server/src/main/java/org/iri_research/renkan/controller/RenkanController.java	Sat Jun 14 13:44:22 2014 +0200
+++ b/server/src/main/java/org/iri_research/renkan/controller/RenkanController.java	Wed Jun 25 15:37:02 2014 +0200
@@ -180,6 +180,7 @@
             nodeIds.put(nodeId, atId);
             nodeNode.put("@id", atId);
             nodeNode.remove("id");
+            nodeNode.remove("project_id");
         }
         
         Iterator<JsonNode> edges = jsonNode.get("edges").elements();
@@ -188,6 +189,7 @@
             edgeNode.put("from", nodeIds.get(edgeNode.get("from").asText()));
             edgeNode.put("to", nodeIds.get(edgeNode.get("to").asText()));
             edgeNode.remove("id");
+            edgeNode.remove("project_id");
         }
 
         String res =  mapper.writerWithDefaultPrettyPrinter().writeValueAsString(jsonNode);