Environmental Health & Safety Compliance Blog

Renewing Wastewater Discharge Permits – Calculating Water Use

Posted by Rebecca McDaniel on Jun 17, 2010 10:57:00 AM

By Sandy Perry, Director of Water Management and Wastewater Services

If you have a wastewater treatment system then you probably (hopefully) have a discharge permit, for which you must have submitted an application to one regulatory agency or another. I’ve found that the section of the application that seems to be the most difficult and takes the most time is where you must list the quantities of wastewater generated from each potential source. This is primarily because few facilities have flow meters on all water use sources.

Ideally, you want to be able to account for the entire volume of water used in a twelve month period. Identifying and quantifying all water uses and the outputs of this water to match the incoming water is typically a challenge. Why? Because it is difficult at best to estimate the amounts evaporated, the boiler blow down quantity, lab sink contributions, or discharges from scrubbers, production operations where some of the water may be consumed in the product or wastes collected for offsite disposal, non-contact cooling (which is clean water and should not go to sewer discharge), RODI reject water, etc.

The best plan is to gather together key people from Facilities, Production, Research, and EH&S to assist in identifying all of the inputs. Piping diagrams are great, but I’ve found that few are kept up to date with piping changes made over the years. Use a white board to begin creating a water mass balance flow diagram and label each box with each water use activity and all of the outputs from each water use source. So for instance, if you have incoming water to your steam boilers, there should be at least two arrows from that box labeled as outputs – evaporation and boiler blow down.

Comparing the total water consumed to the either estimated or metered outputs, you may find that it doesn’t add up. Then you need to review your estimates – what are you missing? What have you double counted? Are your flow meters calibrated? How reliable are they? You may determine the need for additional meters and daily or weekly water use logs. Most regulatory agencies think this is a pretty important aspect of your permit so it’s a good idea to work towards a no more than 1-5% differential between incoming and outgoing water sources. Good luck!

Tags: Wastewater Treatment

Information gap…MWRA versus MassDEP…beware wastewater dischargers

Posted by Rebecca McDaniel on Mar 18, 2010 2:50:00 PM

By Sandy Perry, Director of Water Management and Wastewater Services

How do companies in Massachusetts know which regulations apply to their wastewater sewer discharge? It's interesting how much separation there is between a local authority, such as the Massachusetts Water Resource Authority, and the state authority, the MassDEP. Unfortunately the lack of outreach by either entity typically results in something being missed with respect to compliance.

In fact, no matter which sewer authority a facility in Massachusetts discharges to, wastewater treatment system plans and descriptions must be submitted to the MassDEP along with a staffing plan. Also, facilities are required to have an Operations & Maintenance Manual specific to their system. And depending on the volume discharged, you may need a MassDEP permit as well.

On the other hand, the MWRA (and most local authorities) are most concerned about the characteristics of the wastewater being discharged. They care only that it meets compliance with the sewer use ordinance, local limits, and/or specific permit limits. That is because they have a biological treatment system to protect and their own discharge limits to meet. In most instances you will be required to apply for a discharge permit. However, some of the smaller communities and sewer authorities may not require a permit if your discharge volume is low or you have no chemicals of concern in use.

So my best advice is to do your due diligence before starting up or relocating. Companies need to look into their regulatory obligations prior to moving and understand just what is required. And those already in operation, to be on the safe side, check to make sure that you have made the proper submittals to the MassDEP and/or local sewer authority. (A final word of caution - don't assume that the contractor that installed your treatment system took care of this for you.)

Tags: Wastewater Treatment, Wastewater