For plumbing engineers, the good news is that there are a record number of restaurants and food processors in the United States today. The bad news is that these operations are generating and discharging enormous amounts of fats, oils and grease (FOG), as well as coarse solids, into already overloaded sewage collection lines and treatment plants. But, there really is good news. More and more engineers are designing and installing new kitchen flow before it reaches the collection line. This efficient equipment is also part of a developing trend toward municipal-mandated pretreatment programs for commercial users in sanitary districts.
Long-term trends, such as the progressive tightening of the Clean Water Act regulations and diminishment of funding for replacing/maintaining municipal collection systems, are putting a serious financial squeeze on the nation's sewer districts. As cities encounter increasing difficulty dealing with the cost of servicing food-processing facilities, there has been a correlated increase of mandatory pretreatment programs to coerce restaurants, hospitals, prisons, casinos, schools and other grease discharging sites to do a better job or pay for service costs incurred. Thus, a properly engineered drainage system which incorporates efficient pretreatment gets a free ride. But, to reach this point, it takes the talent and education of a plumbing engineer to evaluate contributing factors.