Sam Judd: How to clean up the water

Water, the solutions are in our hands.

There is little doubt that clean water is up there with the most important challenges facing the environment and our economy.

Last article, I put it to the people to come up with solutions for water pollution. The huge response surprised and encouraged me - it seems that our number-eight wire innovative skills extend well into remedies for water - so I thought, why not share some of them?

Below is just a handful of examples of what we can do in different sectors to reduce impacts on water quality.

Going down the garden to eat worms

I was always fascinated with earthworms, but until studying horticulture, never realised how important they are.

Worms are an essential ingredient for healthy soil, as they rapidly break down organic matter into digestible organic nutrients.

When you have plenty of these little blind soldiers working away, they help to retain nutrients - the escape of which causes significant water quality issues - on the land, as well as water.

A great example is MyNOKE. These guys have created something that has major benefits for cropping, pasture and waste management all in one product.

Dirty dairy the dearth of safe summer dips?

There is little doubt that the expansion of dairy farming is one of the major causes for our water quality decline in rural areas.

Much of this has been caused by a concerted drive towards diary farms achieving bigger and bigger production levels by increasing the number of cows rather than aim to increase production per cow, which, as economist Peter Fraser points out is one way forward for the dairy economy to coexist with clean water.

The drive in production has been coupled with a dramatic increase in fertiliser use, much of which is chemically derived (rather than organic) and therefore escapes the land, polluting water.

Stock numbers are of course causing problems too, but trying to reduce this causes inevitable conflict with farmers. Reducing their fertiliser costs however, is an obvious win-win. If it can be made very clear that farmers will save money by changing practices then perhaps, we can save the waterways.

One example that came through was Precision Agriculture, where economic analysis found that through carefully planning, measuring, managing and reviewing fertiliser use, that they could reduce the average cost of $507/hectare/year, to between $50/ha/year and $114/ha/year ($83/ha/year average) over the previous four whilst still increasing pasture growth.

Another approach that was mentioned to me was instead of testing for just nitrogen, phosphorus and potassium, is to look at all 17 of the essential soil nutrients. This often requires independent soil testing, rather than having tests carried out by the same people who sell farmers the fertiliser (and use testing methods that can often be unsuitable for the soil). One farmer, after having an independent test, dramatically reduced his fertiliser bill straight away and saw profit margins increase immediately.

Gone de loo!

The immediate retort from lobby groups that represent dairy is that other people cause problems too and that water coming from cities is dirtier than that which escapes their areas. Whilst I believe this would be more valid if humans numbered 70 million in New Zealand (which is the equivalent amount of untreated sewage being excreted into our waterways by our 4.6 million dairy cows), having seen the abysmal state of some of our urban waterways it is clear that action needs to be taken: people swim where they live making them more likely to get sick if that water is polluted.

Many houses are using out-dated septic tank systems, which result in swimming and shellfish taking bans after heavy rains because of the e-coli that pours out from sub standard sewage treatment.

Perhaps if people realised the true value of their poo, we could change this. In China, crop-growing peasants living in a shack, would install their toilet next to the road and adorn it with decorations so as to invite travellers to use their facility rather than their neighbour's, because they know the value of it.

Septic tanks can be replaced - or even converted - into biogas digesters. These systems, which have been around for thousands of years in Asia, harvest biogas that can be used to replace fossil fuels, treat the water (in combination with reconstructed wetlands) and produce sustainable organic fertiliser. Everything about this is great I reckon and I will commit to exploring this solution in practice.

What else do you know is out there? If anyone else has got successful examples please share below or send me an email.