Storm Water

PRNZ 519

Storm Water Treatment

Stormwater treatment is evolving as a significant and effective means to protect the natural environment. As councils treat the stormwater from new roading works and residential/commercial subdivisions, so industry must play its part and improve stormwater from its own sites.

Even the best run industrial plant will have some impact on the local environment. This might be from the tracking of contaminants on vehicle wheels to oil loss from vehicles on the site. To continually reduce point and non-point source pollution stormwater treatment is increasingly a requirement for industry.

This is usually a treatment train that includes:

  • Source control – the exclusion of process contaminants from stormwater
  • Stormwater segregation – keeping stormwater out of dirty areas
  • Stormwater treatment devices around the site or at the final discharge point – interceptors, sandfilters, swales, wetlands…

2015 10 12 14.27.06A ‘train’ of treatment devices might give the most practical solution. For example filtration followed by a wetland or planted filter. With water being regarded as a scarce and expensive commodity for industrial applications, the collection and reuse of stormwater for production or general usage is now being widely used. This may include significant filtration or purification processes.

There is often a tension between sending large volumes of stormwater to the sewer and the sewer capacity to receive this. IWS specialises in reducing contaminated stormwater and controlled release to the sewer – with the associated council negotiations and consents. 

How effective is stormwater treatment? IWS has been involved in the design and installation of many stormwater treatment solutions. The AC Technical Publication 10 – Stormwater Management Devices - Design Guideline Manual 2004 (TP 10) – which is in the process if being updated by the Auckland Council in 2016 – drew on some broad international data to gauge the systems’ performance.

IWS can design and install stormwater treatment systems, ranging from:

  • Stormwater collection and reuse
  • Small planted swale or strip filter solutions
  • Rain gardens
  • Small and large engineered sandfilter systems.
  • Cartridge filter-type systems for certain applications.
  • Or a treatment train that includes more than one of these solutions.

Trade Waste

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Trade Waste Treatment

On-site trade waste treatment may be required to achieve compliance and/or reduce disposal costs, whether discharging on-site or to trade wastes systems. Where trade waste discharge consent compliance is not being achieved; IWS can assist with a range of solutions to the problem. These include:

  • pH correction
  • Oil and grease and solvent removal
  • Heavy metals removal
  • Solids and colour removal
  • Segregation of waste streams
  • Existing wastewater treatment plant improvement
  • Containment of process wastewater
  • Vehicle and equipment wash bays

These systems will range from small, "low tech" manual systems, through to complex automated systems, depending on the characteristics and scale of the industry and its wastewater. IWS has considerable experience with anything from a conceptual design to a "turnkey" solution.

Trade Waste Treatment System Design & Build IWS designs and manufactures a range of pollution prevention and trade waste treatment package solutions that can be adapted to your site or mobile application.

IWS has access to Wastewater Treatment Plant components from other manufacturers in NZ and abroad. These package solutions are tailored to suit your particular situation and budget.


Physical - Chemical Treatment (PCT) Modules

IWS has developed a range of modular industrial wastewater PCT plants for those non-compliant wastes. These include: emulsion oils, inks, paints, heavy metals bearing wastewaters. None of these wastes can enter the public sewer without treatment. These all generate a small volume of sludge which is dewatered passively, as part of the module.

The plants can be suited to the site - manual control through to automatic control.