Question: How can the precipitation process be assisted?
About the article "Chemical reaction", section "Precipitation".

Candidate passages:
Precipitation is the formation of a solid in a solution or inside another solid during a chemical reaction.
It usually takes place when the concentration of dissolved ions exceeds the solubility limit and forms an insoluble salt.
This process can be assisted by adding a precipitating agent or by removal of the solvent.
Rapid precipitation results in an amorphous or microcrystalline residue and slow process can yield single crystals.
The latter can also be obtained by recrystallization from microcrystalline salts.
Quantitative precipitation estimation or QPE is a method of approximating the amount of precipitation that has fallen at a location or across a region.
Maps of the estimated amount of precipitation to have fallen over a certain area and time span are compiled using several different data sources including manual and automatic field observations and radar and satellite data.
This process is undertaken every day across the United States at Weather Forecast Offices (WFOs) run by the National Weather Service (NWS).
A number of different algorithms can be used to estimate precipitation amounts from data collected by radar.
Research in the fields of QPE and quantitative precipitation forecasting (QPF) is ongoing. 
In the mountains, much precipitation falls as snow.
Total snowfall peaks around March.
Most precipitation in the area is orographic precipitation.
Near the tops of the mountains, total annual precipitation can exceed per year, while in the valleys it can be as low as . 
Like all other soluble aerosols, increasing normal-sized sea salts suppresses the precipitation process in warm clouds by increasing cloud droplet number concentration and reducing the cloud droplet size.
Also, they invigorate precipitation in mix-phase clouds because once the suppressed smaller cloud droplets are lifted above freezing level, more latent heat content would be released due to the freezing of cloud drops.
Besides that, adding giant sea salt aerosols to polluted clouds can accelerate the precipitation process because giant CCNs could be nucleated into large particles which collect other smaller cloud drops and grow into rain droplets. 
Microbiologically induced calcium carbonate precipitation (MICP) is a bio-geochemical process that induces calcium carbonate precipitation within the soil matrix.
Biomineralization in the form of calcium carbonate precipitation can be traced back to the Precambrian period.
Calcium carbonate can be precipitated in three polymorphic forms, which in the order of their usual stabilities are calcite, aragonite and vaterite.
The main groups of microorganisms that can induce the carbonate precipitation are photosynthetic microorganisms such as cynobacteria and microalgae; sulfate-reducing bacteria; and some species of microorganisms involved in nitrogen cycle.
Several mechanisms have been identified by which bacteria can induce the calcium carbonate precipitation, including urea hydrolysis, denitrification, sulphate production, and iron reduction.
Two different pathways, or autotrophic and heterotrophic pathways, through which calcium carbonate is produced have been identified.
There are three autotrophic pathways exist.
However, all three pathways result in depletion of carbon dioxide and favouring calcium carbonate precipitation.
In heterotrophic pathway, two metabolic cycles can be involved: the nitrogen cycle and the sulfur cycle.
Several applications of this process have been proposed, such as remediation of cracks and corrosion prevention in concrete, biogrout, sequestration of radionuclides and heavy metals.