I think that actually falls within the environmental side of the...

I think that actually falls within the environmental side of the business (i.e., hazardous liquids treatment) rather than water treatment which is chemicals manufacturing - but agree, the new treatment plant is an exciting prospect. They've made some interesting acquisitions in respect of water treatment chemicals - have a look at Aquadex Services and BTX Group in particular. I think both of these companies (now DGL) would have some reasonable IP.

You can get better insight into DGL's current operations by looking into the acquired companies. Here are some interesting ones in addition to the above:

Flexichem - silicone products and toll manufacture
Bondlast - Adhesives and sealants - building and infrastructure. Think restricted to NZL and manufacture their own products with a bit of import.
Aquadec and Hardman Chemicals - Can't find much but related to water treatment.
Chempac NZ (they also acquired Chem Pack, an Australian company, but can't find much info)
Austech Chemicals - Non-oil automotive chemicals, coolants, high performance cleaning, etc.
Triox - Pesticides including home and garden. Water products. They have their own brands as well as toll.
Total Coolant Management Solutions - Water based engine coolants, coolants for wind turbines, cleaning products, etc. Apparently have patented technology.
DLF Global Logistics - Basically freight forwarding. They have offices in Australia and Thailand. They are advertising a high level operations role for this on Seek from memory.
Chempac NZ - Mixing and packing.