CAPACCIO provided wastewater engineering and consulting services to a leading premium chocolate manufacturer. The client was operating a single stage pH neutralization system to neutralize industrial wastewater generated through washing and cleaning operations conducted during the manufacturing of chocolate at its New Hampshire facility. The existing system was designed as part of an acid cleaning operation and was only intended to be used a few times a year. The system consisted of a 500-gallon polyethylene-cone-bottom tank, top mounted agitator, pH probe and controller, caustic metering pump, verification probe, and transfer pumps. Neutralized wastewater is transferred from this system to two underground grease traps located outside of the building.
The wash water generated at the facility was low in pH and flows increased at the facility over the years since the existing neutralization system was installed. Due to the increased flows, facility personnel observed that the pH, as monitored at the discharge location, had approached the lower limit set by the publicly owned treatment works (POTW). In addition, the existing system did not provide redundancy or “fail safes” should a probe or meter malfunction. On several occasions, the pH of the wastewater discharged from the neutralization system was well above the POTW limit, however personnel observed low pH readings at the discharge monitoring point.
To better understand the characteristics of the existing waste streams, CAPACCIO conducted internal sampling at various locations throughout the wastewater system. The sampling provided information regarding the effect that the build-up of solids in the grease traps had on the wastewater discharged to the POTW. CAPACCIO evaluated the sample’s wastewater characteristics and the effects that time and solids build-up may have on the pH of the wastewater. CAPACCIO also developed a sampling matrix identifying sampling locations, sample collection techniques (i.e., grab or composite), and laboratory analyses conducted for each sample; and developed a wastewater sampling plan. CAPACCIO tabulated analytical results and prepared a summary memorandum describing the sampling conducted and discussion of the analytical results.
CAPACCIO also provided the client with opportunities to optimize, modify, or upgrade the existing system in order to increase the system reliability and the client’s ability to meet the POTW pH limits. Another client challenge was to identify locations where the processes that generate industrial wastewater in “Building A” were discharging. This made it difficult to estimate expected flows and pH levels of the wastewater to be treated in the existing neutralization system. It also precluded the client from evaluating how wastewater discharges that do not pass through the system will impact neutralized wastewater downstream.
To properly evaluate wastewater flows through “Building A”, the client needed to identify wet process operations and then determine the discharge location of each operation. This could be done through Discharge Pipe Mapping, which CAPACCIO’s Certified AutoCAD drafting expert provided. CAPACCIO conducted site visits to review current wet process operations generating wastewater. Piping was traced from the processes to their ultimate discharge locations. To establish discharge points, CAPACCIO conducted dye testing where piping cannot be readily accessed or viewed. Based upon data obtained during the site visits, CAPACCIO’s CAD department prepared a process flow diagram indicating wet process operations and discharge locations and when possible, estimated daily or batch flow quantities from each wet process. Along with the process flow diagram, CAPACCIO also updated the building plan with piping runs and discharge locations, and a summary report outlining all findings. Mapping on the existing facility plan allowed the information to be recorded and used for both wastewater and expansion purposes if processes were to be expanded or moved throughout the facility.