Packaged system for the purpose of discussion here should be considered as any waste treatment unit which is in the most part prefabricated or in which many components are factory-built or prefabricated and which can be set up site with more labor being devoted to assembly of components than actual construction on site. Furthermore, these types of units typically have standardization of components which are used in several types and sizes of application; these aforementioned components are also used in multiples for larger unit installations. Their construction is often of lightweight synthetic material such as fiberglass reinforced epoxy, other polymeric materials, or steel and alloys rather than the concrete much smaller amounts of waste, more unique influent character, and/or in more isolated locations than do larger conventional treatment plants. Packaged plants which are in stationary, on-land locations are usually constructed, assembled, and installed above ground level.

            While most problems encountered in the case of packaged treatment units are not unique in the wastewater treatment field, there are several problems that become acute in the field of these packaged systems. These problems occur because of the limitation in type of pollutant waste that being treated. The polluting components of the waste treated in packaged units are often present in much higher concentrations than in typical large municipal waste treatment systems and often there is a nutritional imbalance as far as microflora are concerned the character of the waste is more limited in nature. For example, individual components in a waste derived from a small collection area may reach very high levels which cause problems, while in typical regional municipal systems these troublesome components are diluted and further blended with other types of pollutants.

            Excessive accumulation of ammonia nitrogen can be an aesthetic problem as well as a functional problem. The ammonia odor is displeasing particularly in a workplace or residential area. The pH of an operating system climbs into a highly alkaline range when ammonia level rise, resulting in reduced activity by certain bacteria and reduced efficiency of operation and removal of biochemical oxygen demand (BOD) from the wastewater. 

            Several types of packaged and/or turnkey system have been used with varying success in treatment of wastes other than sanitary sewage. Herbicide and pesticide residues, machine oils, petrochemicals, disinfectants, precursors for manufacturing processes, dyes, and chemical feedstocks all contribute to possible problems sure to be encountered in treatment of industrial wastes. The problems of toxic shock and proper acclimation of microorganisms in the system become apparent when certain industrial wastes are treated. These wastewater influents often contain unusually high concentrations of synthetic, organic, and/or hydrocarbonaceous wastes.

            Institutional, restaurant and hotel wastewater can contain a high concentration of animal and vegetable fats and greases. This grease can accumulate in tanks and lines causing hydraulic problems. Resultant resistance and decrease in flow can cause mechanical failure, displeasing odors, and excessive power use.

            Settleability often becomes a problem in biological waste treatment units and the remedy for this problem in the past has often been the addition of polyelectrolytes which cause various particles to attract because of electrostatic charge, to form larger particles and in turn, to settle more easily within the system. The disadvantage of using such agent is that they add to treatment costs appreciably and that they can on occasion increase sludge volume.

            Often area that may present special problems are : waste that foam, high cellulose waste, pH ranges outside of the neutral range, waste with high and undesirable color and operating waters with high or varying sodium chloride and other salt concentrations.

            Packaged units often experience startup problems which require an “aging” of the microflora in order to acclimate and select the optimal bacteria for the digestion of that particular type of organic waste. This condition lengthens the time it takes before a system is effectively on line with efficient treatment.

Special Programs Encountered with Industrial Wastewater.

            Industrial wastewater often have unique characteristics which yield unique problems to the waste treatment engineer. Wastes that are in themselves toxic, or contain toxic levels of heavy metals, acids, bases, oxidants, etc. are the rule rather than exception. Charges in the intensity of color or odors of industrial wastes may be required. This is often very difficult to effect. 

            Even wasted that are not in themselves toxic often contain imbalances in the carbon : nitrogen : phosphorus ratio that prevent them from being effective treated. Correcting wastes to the proper ratio of pH or nutrient is often most expensive. Nevertheless, bioaugmentation may be a logical approach to the effective treatment of industrial wastewater or to the bioremediation of spills of industrial wastes. Given a sufficient length of hydraulic retention time and proper conditions for bio-oxidation of the waste, bioaugmentation can be used as another tool to add to the efficiency, and reliability of industrial wastewater treatment.