Public Sewer Discharge Permit
ENFORCING THE NATIONAL SEWER DISCHARGE CONTROL REGULATIONS
Preliminary inspections and other guidelines such as the amount of flow, impacting characteristics of the wastewater, type of process, and regulations are taken into consideration to determine if a business is required to have a Public Sewer Discharge Permit.
Public Sewer Discharge Permits are issued (but not limited) to:
Food Packing Plants
Industrial Laundries
Rendering Facilities
Poultry Processors
Bottling Companies
Food Processors & Mfg
Electroplaters
Metal Finishers
Hospitals
Industrial Bakeries
Pharmaceutical Companies
Fuel Service Stations
Hotels
Restaurants
Elderly care homes
Clinics
Vehicle mechanics/panel beaters/sprayers
Carpenters/Aluminium/Glass workshops
Petroleum products storage & processing
Injection moulding facilities
Electronics Mfg plants
Wineries/breweries
Farms (Chicken/pig/cow)
Slaughter Houses
Keeping harmful susbstances out
You can help
The goal of applying for and obtaining a Public Sewer Discharge Permit is to keep harmful substances out that could:
- Interfere with biological treatment process operations;
- Jeopardize worker safety by exposure to chemical hazards;
- Reduce reusability potential of Ne Water due to contaminated effluent and issues with acceptability of biosolids when landfilling;
- Result in violations of the treatment facilities’ own Waste Discharge Requirements imposed by the Environmental Permits issued by ERA;
- Add maintenance, repair, operational and disposal costs to the treatment of wastewater;
Permits to discharge into the sewer contain a series of administrative requirements and discharge conditions that the users must comply with at all times. Permits are given for a one year period, are tailored to each user with applicable conditions and are not renewed automatically.
Below you fill find some sewage treatment considerations and requirements.
Treatment Considerations
Trade effluent generated by industrial entities generally requires some form of treatment. This can range from a simple sedimentation tank to a fully fledged biological treatment plant as illustrated below:
The objective of a sedimentation tank is to remove readily settleable solids and floating material and thus reduce the suspended solids content.
MBBR
A full retention oil/water separator is based on the principle of separation by gravity, the lighter oil and fuel rises to the top while the heavier sludge and sediment settles at the bottom. Clean wastewater then flows out which can be safely discharged into the wastewater system. Full retention interceptors have a specialised float seal which as soon as the oil or fuel reaches the opening to the float chamber, this seal closes and stops water from flowing. It will only resume flowing once the oil or fuel is cleaned out of the chamber. Such interceptors are mandatory to be installed in fuel service stations, car wash stations, and any areas where wastewater can be contaminated with traces of petroleum hydrocarbons. Contaminated waters from the cleaning of oil/water separators must be collected and disposed of by approved treatment facilities
Oil/Water Separator
Treatment of Catering wastewaters
Any catering establishment that prepares food must have a grease trap in order to retain the fats and greases released during washing of pots, pans and other tableware.
There are 3 principal types of grease traps:
Physical
Mechanical
Chemical
A Mechanical grease trap actively removes greases through a mechanically-operated skimming wheel and deposits the waste oils in an external container. These types of units require daily cleaning of the solids collection basket, monthly desludging (sludge not to be disposed to sewer) and annual maintenance.
Physical (Gravity) grease traps use the principle of physical separation by slowing the flow of water inside the trap. This allows fats and greases to become buoyant and to separate. These traps are generally housed below ground and require frequent (once-twice a month) cleaning – depending on the size and load. It is important that the waste cleaning contractor used for cleaning disposes of the oily layer appropriately (i.e. not discharged to sewer). After cleaning, it is important that the grease trap is refilled with water.
A biological grease trap uses a biological agent to degrade the fats and greases present in the wastewater. This requires frequent periodic dosing of an additive generally by the use of a peristaltic pump. Dosage shall be as per manufacturer’s instructions. These types of units require daily cleaning of the solids collection basket, monthly desludging (sludge not to be disposed to sewer), and replacement of additive depending on load and dosing frequency.
Prohibited equipment/treatment systems
The following items are prohibited from being used:
Under-sink food grinders
Macerating equipment for non-biodegradable materials such as bed pads and nappies
Water Softener (unless regeneration reject water is discharged to sea)
How to apply
The process entails filling in the application form and payment of an €11.65 fee. Alternatively, you can use our online portal to register.
Here’s a step by step procedure to help you register online
The fee is applicable only for new applications or other applications that are not renewals (amendment of permit). Secondly, for a new application, we ask the applicants for the following documentation including:
•site plans, internal drains layouts, Material Safety Data Sheets, and any operational permits/licenses the applicant holds with other authorities (such as MTA);
•In case of renewals we also ask for receipts of maintenance/cleaning of treatment facilities and also waste transfer receipts for the movement of wastes which are not authorised to be discharged to sewer;
As part of the permitting process, the entities may also be asked for an analysis of the trade effluent. Sampling guidelines are imposed by the DPU following the review of the documentation submitted and the on-site inspection/s.
At the end of the process, the DPU will issue the permit for a period of one year which is not renewed automatically. Industrial entities are advised to send their application for renewal of their permit at least one month before expiry.
