With increasingly stringent permits and older wastewater systems, often the industrial dischargers are asked to meet new pretreatment goals and pay higher surcharges for increased final effluent requirements. So what can be done to both help the POTW while also lowering costs for the industrial discharger?
The most basic onsite pre-treatment requires monitoring flows and controlling pH. In facilities with high Fats, Oils, & Grease (FOG) or solids, there is usually some type of removal system. This FOG and solids system can be as simple as a grease trap or complex like a dissolved air flotation (DAF) unit.
For soluble organics such as sugars, starches, and proteins, the industrial customer can evaluate the economic efficiency of adding limited biological pretreatment. This is not a full scale secondary wastewater system but rather a high loading rate biological unit. Keys for success include compact foot print, low capital costs, and limited ongoing operation costs. Some common pretreatment biological units include:
- Anaerobic digester
- MBBR aerobic systems
- High rate fixed film systems
- Compact SBR type units
Process to select among options
- Look at current surcharges and determine if more pretreatment is practical
- Questions include how much pretreatment and what are the challenges of including pretreatment
- Evaluate multiple options - many can be low cost without significant ongoing costs associated with operations
- Always ask existing pre-treaters and pre-treatment coordinators about what they see working with similar wastewater