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Water is omnipresent on earth, however, the volume of freshwater amounts to one thirtieth of the water of the salty oceans. This article describes the hydrologic parameters involved in storage and transport of freshwater. Water quality management standards, including EPA specified pollutants are identified. Treatment and techniques to control pollution include in‐plant waste control, minimization separations, adsorption, removal of heavy metals and toxic organics are given.

The formation of soluble microbial products was evaluated in batch reactors using radiolabeled 14C-phenol and 14C-glucose. Soluble microbial products, SMP, resulted from intermediates or end products of substrate degradation and endogenous cell decomposition. On an organic carbon basis, the SMP produced after A8 hours averaged 1A.7 (±3.7) percent of the initial phenol and 3.1 (±0.4) percent of the initial glucose. The SMP were categorized as substrate utilization products, having a biodegradable and non-biodegradable fraction, and biomass associated products, which were only non-biodegradable. A model was developed based on kinetic relationships between several macroscopic compartments, which consisted of the initial substrate, cell mass, and the three SMP categories. Based on the experimental data, zero and first order kinetics were sufficient to describe the disappearance of the initial substrates and the net SMP, i.e., total SMP produced less SMP biodegraded to yield CO2 and/or new biomass. Both phenol and glucose adhered to the same kinetic model, but the rate constants were considerably different.

The molecular weight, MW, distribution of soluble microbial products, SMP, was examined. Phenol, an inhibitory substrate, and glucose, a non-inhibitory substrate, were degraded using acclimated cultures of bacteria. Three distinct regions were found to exist, Region I: Original substrate present, Region II: Biodegradable SMP present, and Region III: Endogenous respiration. Phenol degradation resulted in more SMP than glucose, about 25 percent versus 3 percent as residual SMP at the end of Region I, and 3 percent versus 1 percent at the end of Region II, respectively. In Region III, the production of SMP due to endogenous decay, SMPE, was proportional to the rate of cell degradation. The rate coefficient for SMPE production for cells grown on phenol was higher than for glucose, 0.005 mg SMPE per mg cell carbon per day for phenol versus 0.002 mg per mg per day for glucose. Although differences existed in the magnitude of SMP produced, the MW distributions for phenol and glucose were similar in each region. While in Region I most of the SMP consisted of the lowest MW (<1 K daltons) compounds, 90 percent for phenol and 75 percent for glucose, at the end of Region II only 41 percent of the SMP for phenol and 56 percent for glucose were in the <1 K fraction. Finally, for endogenous decay products, 48 and 50 percent of the SMPE were in the highest MW fraction >100 K.