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Wastewater- How to prevent a stinky situation

When you’re developing property, most of you will start with the exciting things - where is the building going to go, what will it look like, what will be inside? You come to a point though where you need to think about the not so exciting things- like services! Your resource consent will need to show how you intend to service your site. You may have seen our recent blogs about stormwater tanks, and this article gives you a brief overview of wastewater.

What is wastewater?

Wastewater is the water you dispose of and it comprises blackwater and greywater. Blackwater is wastewater containing

human waste (e.g. from the toilet). Greywater is the water from dishwashers, kitchen, laundry and bathrooms. Dishwater and kitchen water cannot be recycled because it contains fats, detergents and cleaning agents, and can contain bacteria such as campylobacter and salmonella. Blackwater and kitchen water must be treated through an on-site or mains sewage system. It can be a public health risk if not handled properly[1]. Other greywater may be able to be used for flushing toilets and watering the garden.

Wastewater in Urban Areas

In urban areas, wastewater management is generally more straight forward; you will probably have access to a public reticulated wastewater network and can connect to that. You can check this by looking at the Council’s GIS maps - you can select the services overlay and this will show you the location of the service lines (it’s not 100% accurate but is useful for preliminary planning).

Often you will need to do some investigations on capacity, to make sure the network has capacity to service your development. You should do these investigations in the early stages of development planning, as the servicing can have big impacts on design and costs. It can also trigger additional planning infringements, requiring resource consent. The service provider (Watercare Services in Auckland) will also likely charge you to make a new connection.

Wastewater in Rural Areas

In rural areas, usually there is no public or reticulated wastewater service and you need to collect, treat and dispose of your wastewater on site. The suitability of a site for this is usually investigated on a basic level at subdivision stage - making sure the site is big enough, there is land suitable for discharge (e.g. not in floodplains, near watercourses etc) and the soils are suitable. Design of a system however occurs when you know what development you propose. This is because the type and scale of the development affects the type and volume of wastewater, which in turn effects the type of treatment and disposal required. The design of a wastewater system is undertaken by a specialist; we have a number of good contacts and can manage this for you. You also need to remember that you can require a resource consent for your wastewater discharge. This can usually be “bundled” in with your other resource consent infringements, into one application.

How do on- site systems work?

Wastewater is piped to the on-site system which consists of one or more chambers. Modern aerated and advanced wastewater treatment systems (AWTS) apply a number of treatment steps including:

  1. separate solid waste from wastewater. Solids settle on the bottom of the chamber, and light waste such as fats and grease floats to the top;

  2. effluent passes through filter to aeration chamber. Pumped in air creates turbulence and aerates effluent. The chamber may incorporate a bioreactor to give additional bacterial treatment,

  3. effluent passes through second, finer filter to clarification chamber. Fine sludge particles settle and are pumped back to the first chamber,

  4. discharge of the treated wastewater through pipes into a soakage treatment area or tank where, depending on the system’s treatment level, it can be used for watering the garden, toilet flushing and other applications.

If the treated effluent is to be discharged onto the land, you need to think about where this will be as it can restrict what you can use the land for. Properly set up, installed and maintained, on-site sewage systems treat wastewater to remove pathogens and chemical residues. Maintenance is very important, as not only can a poorly maintained system affect your health in the short term, it can also contaminate the ground over time, affect local watercourses and have other ecological impacts.

Want more information on rural development?

At Planning Plus, our staff have extensive experience in the rural environment; Hannah and Anne in particular have been working in the rural environment for over 17 years. Our team has detailed knowledge of the unique factors affecting development in rural areas- let us make the process easy for you!

Hannah Thomson is Director of Planning Plus and has over 17 years of resource management experience working in both local government and the private sector. Hannah has a wide range of experience including commercial, rural, residential and coastal development and subdivision on small to large scales and appearances at both Council and Environment Court as an expert witness for mediation and hearings. Hannah has assisted Councils with policy development and has also assisted private individuals with submissions to Council.

Disclaimer As with all our blogs, the information detailed here is general in nature and meant as a preliminary guide only. This should not be substituted for your own investigations or use of your own professional’s. Planning Plus is not liable for any errors or omissions.

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