The main goal of this review is to collect and analyze the recently published research concerning the conventional and sustainable treatment processes for olive mill wastewater (OMW). In the conventional treatment processes, it is noticed that the main objective is to meet the environmental regulations for remediated wastewater without considering the economical values of its valuable constituents such as polyphenols. These substances have many important environmental values and could be used in many vital applications. Conversely, sustainable treatment processes aim to recover the valuable constituents through different processes and then treat the residual wastewater. Both approaches’ operational and design parameters were analyzed to generalize their advantages and possible applications. A valorization-treatment approach for OMW is expected to make it a sustainable resource for ingredients of high economical value that could lead to a profitable business. In addition, inclusion of a recovery process will detoxify the residual OMW, simplify its management treatment, and allow the possible reuse of the vast amounts of processed water. In a nutshell, the proposed approach led to zero waste with a closed water cycle development.

The agglomeration behavior in adipic acid crystallization from aqueous solution was experimentally studied under different crystallization conditions. The QICPIC software, which uses image analysis technique, was implemented to evaluate the agglomeration behavior of adipic acid crystals. Primary experimental investigations indicated an important role of cooling rate on the agglomeration and crystal size distribution (CSD) of adipic acid. At slower cooling rates of 17.5 K/h and 6 K/h, larger size particles (80% agglomerates) with bimodal and wide CSD were produced while at a higher cooling rate of 30 K/h a narrower unimodal PSD and smaller size particles with the ratio of agglomerated particles of about 80% were produced. The influence of pH was found to be an important factor when studying the agglomeration behavior of adipic acid. A larger size of the product was measured in the strong acidic medium, indicating enhanced agglomeration. Changing the solvent composition and its effect on the agglomeration of adipic acid were studied. A bimodal and larger size agglomerates are obtained in a pure water solvent while adding ethanol will change the CSD to unimodal shape (no nucleation) with smaller sized agglomerates.