You can use this code to use the numeric value returned by your SQL query to get the text value of the enum:
Dim TaskActivityTypeName As String = CType(taskActiveFromSqlNumeric, TaskActivityType).ToString()
and here are all the values in a listing (I used the code above to generate this list):
Unknown = -1
RecycleApplicationServer = 10
GetDataCells = 100
GetDataCellsUsingScript = 101
GetExcelData = 102
CubeView = 110
CubeViewReport = 111
ExportCubeViewToExcel = 112
QuickView = 120
Book = 200
DataManagement = 1000
DataManagementScheduledTask = 1100
LoadAndTransformSourceData = 2000
BIBlendLoadAndTransformSourceData = 2100
DirectLoadAndTransformSourceData = 2200
RetransformSourceData = 3000
ClearStageData = 4000
PreserveStageData = 4100
RestoreStageData = 4200
ClearPreservedStageData = 4300
ValidateTransformation = 5000
ValidateIntersections = 6000
LoadCube = 7000
LoadAndProcessCube = 7001
LoadCubeBatch = 7002
ProcessCube = 8000
ClearCubeData = 8400
ClearCubeDataForWorkflow = 8500
Confirm = 8600
Certify = 8700
Calculate = 9000
Translate = 10000
Consolidate = 11000
Aggregate = 11001
WorkflowViewBatch = 12000
MultiWorkflowViewBatch = 12500
WorkflowFileBatch = 13000
LoadXml = 15000
AzureEDTUScaling = 16000
AzureServerScaling = 16100
LockFxRate = 17000
UnlockFxRate = 17100
AnalyticsApi = 20000