Chemical Extraction of Phosphorus from Dairy Manure and Utilization of Recovered Manure Solids

Repeated land application of dairy manure can increase soil phosphorus above crop requirements because of manure’s low nitrogen (N) to phosphorus (P) ratio (N:P < 4:1). This soil P build-up can lead to off-site P transport and impairment of surface water quality. We evaluated a treatment process to extract P from manures, called Quick Wash, integrated with a double-stage solids separation system to recover coarse and fine manure solids. The Quick Wash process uses a combination of acid, base, and organic polymers to extract and recover P from manures, improving the N:P ratio of recovered manure solids (RMS). Results showed that coarse RMS could have use as bedding materials for dairy cows, and the fine acidified RMS with N:P > 10:1 can be used as a low-P organic soil amendment. A soil incubation test showed that acidified RMS stimulated N mineralization and nitrification having higher nitrate levels than untreated dairy slurry when incorporated into soil. Our results suggest that the inclusion of Quick Wash in a dairy manure management system can improve manure’s value, lowering costs of bedding material and manure hauling, and recover P for use as fertilizer while reducing the environmental impact of land spreading manure P.

A New Generation of Submersible Electrical Motor Protectors with a Dynamic Labyrinth for Operation in Aggressive Environment with High Concentration of Free Gas and Solids

In this work, the authors study the problems associated with the operation of oil wells using electric centrifugal pumps. The authors acknowledge the negative factors that lead to an increase in solids concentration in the upper part of the submersible electric motor protectors, higher possibility of end seal failures and shortening of service life of serial products. The replacement of a gravitational labyrinth by a dynamic one in the upper part of the motor seal protector is one of the ways to improve the reliability of the protector in the operational environment with high concentration of gas and solids. The proposed seal protector design makes it possible to considerably increase the estimated efficiency of solids separation (by 300 times), improve reliability, as stable running is ensured even after the failure of end seals, and reduce the mounting length by 25–40 %, resulting in cost saving and improved maintainability as fewer parts are used. This conceptually new operation principle facilitates the creation of a new generation of highly reliable seal protectors, capable of working effectively in challenging well conditions. Thus, the new design should supersede all serial motor seal protectors in conventional wells and add a market segment in complicated wells.