glossary

Glossary

Owls Hall Environmental Services

We admit that there is a fair bit of jargon used in the construction industry and we hope to smash some of that here. We’re happy to help and always offer free advice over the phone, so if you have a question about any aspect of your water treatment or drainage give us a call on 01371 850537.

Ammonia

Ammonia (NH4), in wastewater generally comes from Urine, It is toxic to plants and fish. Nitrifying bacteria in a treatment plant use Oxygen to convert Ammonia into Nitrite (NO2). Different bacteria in the treatment plant also using Oxygen convert the Nitrite to Nitrate (NO3).

Nitrate is far less harmful to the environment and therefore acceptable to release into the ground. Most treatment plants will also have a De-nitrification stage which allows time for Nitrate to be converted into Nitrogen Gas (which is perfectly safe) These treatment plants will, if sized correctly will often produce a better quality of final effluent

If you have any questions or would like us to examine the site – free of charge – call us on 01371 850537.

Backed up drain

Contents of the drain returning from the pipework, which may occur after a heavy rainfall. It could indicate a problem with your sewage treatment plant, septic tank or pumping station or with a soakaway on your land.

If you have any questions or would like us to examine the site – free of charge – call us on 01371 850537.

Blackwater

All types of residential, commercial and industrial wastewater contaminated with bacteria, viruses, parasites and various types of organic material, including faecal matter and urine; also known as “wastewater”, “foul water” or “sewage”.

BOD (Biological Oxygen Demand)

Indicator telling us how much dissolved oxygen would be needed by microorganisms to oxidise all of the organic elements in a measurement of water; usually expressed in mg/L – the lower the value, the higher the quality of water. BOD is used to assess the efficacy of wastewater treatment plants.

Borehole

A narrow shaft excavated in the ground, horizontally or vertically; can be used to assess environmental conditions of the site, and also to supply drinking water or as method of ground source heating.

Building notice

A way of applying for Building Regulations approval. With a building notice you only need an application form, sometimes a block plan (depending on the type of development you’re undertaking) and you need to pay a fee. It’s relatively quick to prepare and process, however it may not be suitable for large-scale projects.

Read more on the Government Planning Portal

CCTV cameras

Sometimes called a drain camera or sewer camera and which is specially designed to be inserted inside pipework as a way of diagnosing issues.

Cesspool/Cesspit

A sealed hole in the ground with walls strengthened by concrete or brick; a cesspool is designed to receive wastewaterand contain it without treatment. The size of the tank for a property is regulated by the Building Inspector at your Local Council. For a single dwelling 18180 litres (4000 gallons) is the minimum allowable capacity suitable for two residents only. This size should be increased by 6,800 litres for each additional user. You will need to have the cesspool emptying and this can be a frequent occurrence. Be aware that some councils will not allow cesspools, and we would always recommending looking to a sewage treatment plant as the best option for wastewater treatment.

Consent to Discharge

A document issued by the Environment Agency, giving you permission to release effluent to inland freshwaters, coastal water or estuaries or ground waters or land. Most treatment plants and septic tank systems are exempt from a consent to discharge, but contact us if you have further questions.

DEFRA

Department for Environment, Food & Rural Affairs– a Government department responsible for policy and regulations on environmental, food and rural issues.

Desludging

Process of taking out solid residue (sludge) by draining and cleaning the tank.

Discharge

Discharge or effluent is the fluid produced as a result of a septic tank or wastewater treatment plant’s filtration system.

Drainage field (see leaching field)

Also known as a soakaway or a drainage field, is an area used to disperse the untreated effluent from a septic tank or treated effluent from a treatment plant where a ditch is not available into the ground.

Drainage Mound

An overground alternative for a soakaway. It may be suitable for sites with a high water table, shallow layer of soil or soil with very fast or slow absorptive qualities. Although it may be a solution for some sites, where an installation of a septic tanks would not be possible, there are several elements that need to be taken into account:

  • Construction costs are usually greater than the cost of installing a traditional system
  • Visual impact on the landscape is unavoidable
  • The solution will require a dedicated pumping system

If you require more information, call us on 01371 850537.

Dry site

An excavation with groundwater level located below the base of the dig.

Effluent

Product of a septic tank’s or wastewater treatment plant’s filtration system

Effluent Pump (see pumping station)

A construction consisting of pumps and equipment supporting the transportation of fluids to a desired destination; pumping stations of various designs can be installed in individual houses as well as large-scale commercial developments. They may be used to deliver water, drain land endangered with flooding and to transport sewage to treatment plants.

Environment Agency

Governmentnon-departmental agency sponsored by DEFRA.

Exemption from Consent to discharge

According to the official website, “small discharge of domestic sewage effluent from septic tanks and package treatment plants” are exempt from having to apply for the consent.

Exit pipe

An element of the system that transports the sewage away from the building and to the treatment system.

Flow rates

Indicator of much of a fluid can pass through a system in a given unit of time

Glass Reinfored Plastic (GRP) also known as Fibreglass

Strong and cost effective building material known for its strength and durability, and which can be moulded into various shapes. Commonly used in aeronautics, cars, pipes, cladding, tanks – for water treatment plants and rainwater collection.

Gravity system

System relying on gravity to transport the fluid through the pipework. May not be suitable for sites where pipework needs to go up a slope or around an obstacle.

Grease separator

A device designed to separate grease and fat from wastewater flow; usually allowing easy access to the collected solids, enabling its safe disposal.

Greywater

Dirty water from showers, baths, laundry, etc. It can be recycled for re-use or safe disposal.

Groundwater

Water beneath Earth’s surface; the term describes liquid water as well as soil moisture, frozen soil (or permafrost), immobile water in bedrock with low absorbency rate, geothermal and oil formation water. Groundwater levels are renewed by water permeating from the surface, so its level may vary between seasons, and it naturally flows to the surface as well, in a form of springs, lakes, etc. It can also be accessed by man-made excavations, like wells.

Influent

Material flowing into a designated area.

Invert level

A measurement from ground level to the bottom of the inlet pipe of the effluent system

Jet washing

Cleaningof drainage pipes with high pressure water. Effective at removing blockages.

Klargester

Company created in 1955, manufacturer of package pollution control products, including wastewater treatment systems, reed beds, oil separators, grease traps, pumping stations and stormwater collection solutions. We supply and install a variety of Klargester products.

Leaching Field

Also known as a soakaway or a drainage field, is an area used to disperse the untreated effluent from a septic tank or treated effluent from a treatment plant where a ditch is not available into the ground.

Mains sewer

A network of pipes, through which your mains water supplier takes your sewage for you and treats it at the sewage works.

Package Treatment Plant (see sewage treatment plant)

A more sophisticated way of treating wastewater. It treats raw sewage into a treated effluent, which is of sufficient quality to be discharged into a watercourse. This is a solution recommended by most local authorities, and is ideal for properties without suitable room or conditions for a drainage field/soakaway.

Percolation test / Porosity test

An examination to determine how quickly the soil in your area can absorb water.Visit our How To section for details on how to carry out this test yourself.

Polyethylene

(C2H4)n, one of the most frequently used plastics; can be moulded to obtain a desired shape, its durability, strength and high resistance to chemicals makes it a greatmaterial for storage tanks. Our Solido sewage treatment plants and F-Linerainwater harvesting tanks are constructed from 8mm polyethylene.

Planning Permission

A document issued by your local planning authority, granting you consent to build on land or change its use. It may also be required when you intend to change the use of building already erected on the land. Planning permission is not usually neededwhen you install a water treatment system or replace an old one.

PremierTech Aqua

World leader in manufacturing tanks for stormwater and sewage treatment, PremierTech Aqua recently acquired German company, Rewatec and their range of polyethylenetanks and wastewater treatment systems. With a head office in Peterlee, County Durham, and over 90years of experience in the market they are one of our most reliable partners in delivering high quality water solutions. You can find out more about them on their website.

Pumped System

A system fully operated by the pump; as it does not rely on gravity for circulation, it can give the designer more flexibility, however it may be necessary if the system has to be built at the bottom of a hill or go around an obstacle.

Pumping Station

A construction consisting of pumps and equipment supporting the transportation of fluids to a desired destination; pumping stations of various designs can be installed in individual houses as well as large-scale commercial developments. They may be used to deliver water, drain land endangered with flooding and to transport sewage to treatment plants.

Rainwater Harvesting

Process of accumulating rainwater with a view of using it on the premises. Rainwater can be used to water plants in the garden – and avoid any hose pipe bans, for washing cars and doing laundry. Read more about the benefits of rainwater harvesting by clicking here. Traditionally water was collected in water butts, however it typically stores up to 200l of water, which is not enough to fulfill the needs of a modern household. There are systems available that can be connected directly to the house and store as much water as you need in an underground tank.

Reed Beds

An artificially created, sustainable habitat, developed for additional filtration of treated effluent. Its efficiency depends on the water purifying characteristics of a specially chosen plants (like common reed), microorganisms as well as the soil and gravel and/or sand. Deemed beneficial for wildlife, reed beds are relatively easy to install and maintain.

Sample Chamber

Where a sample point is not accessible at the property a sample chamber is used to retain a volume of the treated effluent prior to entering the watercourse.

Sample Point

This is the location identified on the Environment Agency’s Consent to Discharge where a sample can be taken of the treated effluent prior to entering the watercourse.

Septic Tank

A way of treating sewage on a small scale. Unfortunately, septic tanks treat the wastewater only partially and further (secondary or tertiary) filtration is needed – all septic tanks require a soakaway. Please note that it is illegal to discharge directly into a watercourse from a septic tank.

Sewage Treatment Plant

A more sophisticated way of treating wastewater. It treats raw sewage into a treated effluent, which is of sufficient quality to be discharged into a watercourse.This is a solution recommended by most local authorities, and is ideal for properties without suitable room or conditions for a drainage field/soakaway.

Sludge

A residue of soft substance created as a product of sewage treatment process; it separates from the liquid and needs to be removed from the system on a regular basis (the process is known as desludging), in order to keep the septic tank or a wastewater treatment plant running smoothly.

Soakaway (see leaching field)

Also known as a soakaway or a drainage field, is an area used to disperse the untreated effluent from a septic tank or treated effluent from a treatment plant where a ditch is not available into the ground.

Stormwater

Rainwater, as well as melted snow and ice. Stormwater could be water from the roof that enters the foul drain system through your roof down pipes or from yard gullies. Please note that storm water should not enter an effluent system, since this dilutes the bacteria and may create an illegal discharge to the water course. Where connection to mains drainage is being considered this is also a requirement of the Water Companies that the stormwater is excluded from the foul system.

How to establish if the foul system receives storm water

Choose a day when it’s not raining and make sure there’s no water running inside the house or any other buildings. Run a hose pipe into the down pipe or yard gully to see if this water is passing through the inspection chamber prior to the septic tank.

It may also be helpful to check the inspection chamber prior to the septic tank when there is a heavy rain with no water running in the house or buildings and this may show if any water is entering the system or if any pipes are cracked where water may be seeping into the foul pipe system.

If you discover storm water is entering into the foul system make a plan of your property and identify the areas that need redirecting. We can help, call us on 01371 850537 for a free site inspection.

If you have difficulty in establishing the layout of the drains, our engineers can use drain dye to help establish the path (an outside working water tap would need to be provided free of charge). They also carry a Cat and Genny system with a sonde. The sonde is shaped like a mole and it can be passed through the drains sending a signal to the receiver above ground providing approximate depth and location.

Tankering

Liquid waste transportation, shipping the sludge or biomass pumped out of your septic tank or water treatment system to be safety disposed of at a dedicated site.

Total Nitrogen

Contaminated water contains nitrogen present as organic nitrogen and ammonia. Then, in time, even organic nitrogen is transformed into ammonia and when the conditions are right, it is oxidised into nitrite, and then into nitrate. Subsequently, when nitrite and ammonia nitrogen are at their lowest levels, and nitrate is at its highest, the sewer is fully nitrified, which means it has a very low level (or none)of organic nitrogen. So, Total Nitrogen (TN) is the total number of nitrate-nitrogen (NO3-N), nitrite-nitrogen (NO2-N), ammonia-nitrogen (NH3-N) and organically bonded nitrogen.

TSS (total suspended solids)

A measurement determining the quality of water. A sample of water is filtered through a pre-weight filter and the deposit is then dried, and the filters are weighed again. The difference in values between the reading give the total suspended solids in a sample, usually expressed in milligrams per litre or mg/L.

Watercourse

Term used by the Environment Agency to describe a ditch, stream, river, canal, lake, lock or pond.

Wet Site

A location where groundwater lies above the base of excavation at any time. Some sites may, at the time of the work being carried out, be dry sites; however, changes in the water table may turn it in to a wet site.We install all of our sewage treatment systems and septic tanks as wet site installations to ensure that water changes won’t effect the running of your system.

WPL

WPL are a specialist supplier of process sewage and wastewater treatment solutions. They are based in Hampshire, but have international reach. Their long standing manufacturing expertise make them one of our trusted suppliers.